@article {1653,
	title = {Gold nanomaterials as key suppliers in biological and chemical sensing, catalysis, and medicine},
	journal = {Biochimica et Biophysica Acta (BBA)-General Subjects},
	year = {2020},
	author = {Falahati, M. and Attar, F. and Sharifi, M. and Saboury, A.A. and Salihi, A. and Aziz, F.M. and Kostova, I. and Burda, C. and Priecel, P. and Lopez-Sanchez, J.A. and Laurent, S. and Hooshmand, N. and El-Sayed, M.A.}
}
@article {1658,
	title = {Observation of Photoinduced Proton Transfer between the Titania Surface and Dye Molecule},
	journal = {The Journal of Physical Chemistry C},
	year = {2020},
	author = {Nishikiori, H. and Kondo, H. and Kageshima, Y. and Hooshmand, N. and Panikkanvalappil, S. R. and Valverde-Ch{\'a}vez, D.A. and Silva, C. and El-Sayed, M.A. and Teshima,K.}
}
@article {1659,
	title = {Plasmonic and chiroplasmonic nanobiosensors based on gold nanoparticles},
	journal = {Talanta},
	year = {2020},
	author = {Sharifi, M. and Hosseinali, S.H. and Alizadeh, R.H. and Hasan, A. and Attar, F. and Salihi, A. and Shekha, M.S. and Amen, K.M. and Aziz, F.M. and Saboury, A.A. and Akhtari, K. and Taghizadeh, A. and Hooshmand, N. and El-Sayed, M. A. and Falahati, M.}
}
@article {1654,
	title = {Collective multipole oscillations direct the plasmonic coupling at the nanojunction interfaces},
	journal = {Proceedings of the National Academy of Sciences},
	year = {2019},
	author = {Hooshmand, N. and El-Sayed, M.A.}
}
@article {1643,
	title = {Monitoring the dynamics of hemeoxygenase-1 activation in head and neck cancer cells in real-time using plasmonically enhanced Raman spectroscopy},
	journal = {Chemical Science},
	year = {2019},
	author = {Panikkanvalappil, S. R. and Garlapati, C. and Hooshmand, N. and Aneja, R. and El-Sayed, M. A.}
}
@article {1651,
	title = {Plasmonic gold nanoparticles: Optical manipulation, imaging, drug delivery and therapy},
	journal = {Journal of Controlled Release},
	year = {2019},
	author = {Sharifi, M. and Attar, F. and Saboury, A.A. and Akhtari, K. and Hooshmand, N. and Hasan, A. and El-Sayed, M.A. and Falahati, M.}
}
@article {1639,
	title = {Gold Nanorod-Photothermal Therapy Alters Cell Junctions and Actin Network in Inhibiting Cancer Cell Collective Migration},
	journal = {ACS nano},
	year = {2018},
	author = {Y. Wu and Ali, M. R. K. and B. Dong and T. Han and K. Chen and J. Chen and Y. Tang and N. Fang and F. Wang and El-Sayed, M. A.}
}
@article {1634,
	title = {Single-Crystal Electrospun Plasmonic Perovskite Nanofibers},
	journal = {The Journal of Physical Chemistry C},
	year = {2018},
	author = {A.M. Abdellah and A. Hafez and Panikkanvalappil, S. R. and El-Sayed, M. A. and Allam, N. K.}
}
@article {1596,
	title = {High-sensitivity molecular sensing using plasmonic nanocube chains in classical and quantum coupling regimes},
	journal = {Nano Today},
	year = {2017},
	keywords = {display},
	author = {Hooshmand, Nasrin and et al.}
}
@article {1605,
	title = {Meniscus-assisted solution printing of large-grained perovskite films for high-efficiency solar cells},
	journal = {Nature Communications},
	year = {2017},
	keywords = {display},
	author = {He, M and et al.}
}
@article {1616,
	title = {Carrier dynamics and the role of surface defects: Designing a photocatalyst for gas-phase CO2 reduction},
	journal = {Proceedings of the National Academy of Sciences},
	year = {2016},
	author = {Hoch, L. B. and et al.}
}
@article {1624,
	title = {Effects of the substrate refractive index, the exciting light propagation direction, and the relative cube orientation on the plasmonic coupling behavior of two silver nanocubes at different separations},
	journal = {Journal of Physical Chemistry C},
	year = {2016},
	author = {Hooshmand, N. and et al.}
}
@article {1590,
	title = {Elucidation of Ultraviolet RadiationInduced Cell Responses and Intracellular Biomolecular Dynamics in Mammalian Cells Using Surface-Enhanced Raman Spectroscopy},
	journal = {Chemical Science },
	year = {2016},
	author = {Panikkanvalappil, S. R. and Hira, S. M. and El-Sayed, M. A.}
}
@article {1584,
	title = {Hyperoxia Induces Intracellular Acidification in Neonatal Mouse Lung Fibroblasts: Real-Time Investigation Using Plasmonically Enhanced Raman Spectroscopy},
	journal = {Journal of the American Chemical Society},
	volume = {138},
	year = {2016},
	pages = {3779{\textendash}3788},
	author = {Panikkanvalappil, Sajanlal R. and James, Masheika and Hira, Steven M and Mobley, James and Jilling, Tamas and Ambalavanan, Namasivayam and El-Sayed, Mostafa A.}
}
@article {1592,
	title = { Photoexcited Surface Frustrated Lewis Pairs for Heterogeneous Photocatalytic Co2 Reduction},
	journal = { Am. Chem. Soc. },
	year = {2016},
	author = {Ghuman, K. K. and Hoch, L. B. and Szymanski, P. and Loh, J. Y. and Kherani, N. P. and El-Sayed, M. A. and Ozin, G. A. and Singh, C. V.}
}
@article {1585,
	title = {The Sensitivity of the Distance Dependent Plasmonic Coupling between Two Nanocubes to their Orientation: Edge-to-Edge versus Face-to-Face},
	journal = {The Journal of Physical Chemistry C},
	volume = {120},
	year = {2016},
	pages = {4564{\textendash}4570},
	author = {Hooshmand, Nasrin and Bordley, Justin A and El-Sayed, Mostafa A.}
}
@article {1572,
	title = {The Coupling between Gold or Silver Nanocubes in Their Homo-Dimers: A New Coupling Mechanism at Short Separation Distances},
	journal = {Nano Letters},
	volume = {15},
	year = {2015},
	pages = {3391-3397},
	doi = {10.1021/acs.nanolett.5b00734},
	url = {http://dx.doi.org/10.1021/acs.nanolett.5b00734},
	author = {Bordley, Justin A and Hooshmand, Nasrin and El-Sayed, Mostafa A.}
}
@article {1577,
	title = {Plasmonic Spectroscopy: The Electromagnetic Field Strength and its Distribution Determine the Sensitivity Factor of Face-to-Face Ag Nanocube Dimers in Solution and on a Substrate},
	journal = {The Journal of Physical Chemistry C},
	volume = {119},
	year = {2015},
	pages = {15579-15587},
	doi = {10.1021/acs.jpcc.5b05395},
	url = {http://dx.doi.org/10.1021/acs.jpcc.5b05395},
	author = {Hooshmand, Nasrin and Bordley, Justin A and El-Sayed, Mostafa A.}
}
@article {1367,
	title = {Are hot spots between two plasmonic nanocubes of silver or gold formed between adjacent corners or adjacent facets? A DDA examination},
	journal = {The Journal of Physical Chemistry Letters},
	year = {2014},
	isbn = {1948-7185},
	author = {Hooshmand, Nasrin and El-Sayed, Mostafa A. and Bordley, Justin A}
}
@article {1368,
	title = {P-Glycoprotein-Dependent Trafficking of Nanoparticle-Drug Conjugates},
	journal = {Small},
	volume = {10},
	number = {9},
	year = {2014},
	pages = {1719-1723},
	isbn = {1613-6829},
	author = {Dreaden, Erik C. and Raji, Idris O and Austin, Lauren and Fathi, Shaghayegh and Mwakwari, Sandra C and Humphries, William H and Kang, Bin and Oyelere, Adegboyega K and El-Sayed, Mostafa A}
}
@article {1366,
	title = {The Spectroscopy of Homo and Heterodimers of Silver and Gold Nanocubes as a Function of Separation: a DDA Simulation},
	journal = {The Journal of Physical Chemistry A},
	year = {2014},
	isbn = {1089-5639},
	author = {Hooshmand, Nasrin and O{\textquoteright}Neil, Daniel and Asiri, Abdullah M and El-Sayed, Mostafa A.}
}
@article {1396,
	title = {Plasmonic enhancement of photodynamic cancer therapy},
	journal = {Journal of Photochemistry and Photobiology a-Chemistry},
	volume = {269},
	year = {2013},
	note = {Hayden, Steven C. Austin, Lauren A. Near, Rachel D. Ozturk, Ramazan El-Sayed, Mostafa A.},
	month = {Oct},
	pages = {34-41},
	isbn = {1010-6030},
	doi = {10.1016/j.jphotochem.2013.06.004},
	author = {Hayden, S. C. and Austin, Lauren and Near, R. D. and Ozturk, R. and El-Sayed, M. A.}
}
@article {1380,
	title = {Rapid and Efficient Prediction of Optical Extinction Coefficients for Gold Nanospheres and Gold Nanorods},
	journal = {Journal of Physical Chemistry C},
	volume = {117},
	number = {45},
	year = {2013},
	note = {Near, Rachel D. Hayden, Steven C. Hunter, Ronald E., Jr. Thackston, Daniel El-Sayed, Mostafa A.},
	month = {Nov},
	pages = {23950-23955},
	isbn = {1932-7447},
	doi = {10.1021/jp4082596},
	author = {Near, R. D. and Hayden, S. C. and Hunter, R. E. and Thackston, D. and El-Sayed, M. A.}
}
@article {1381,
	title = {Thin to Thick, Short to Long: Spectral Properties of Gold Nanorods by Theoretical Modeling},
	journal = {Journal of Physical Chemistry C},
	volume = {117},
	number = {36},
	year = {2013},
	note = {Near, Rachel D. Hayden, Steven C. El-Sayed, Mostafa A.},
	month = {Sep},
	pages = {18653-18656},
	isbn = {1932-7447},
	doi = {10.1021/jp4078344},
	author = {Near, R. D. and Hayden, S. C. and El-Sayed, M. A.}
}
@proceedings {1377,
	title = {Toxicities and antitumor efficacy of tumor-targeted AuNRs in mouse model},
	volume = {73},
	number = {8},
	year = {2013},
	publisher = {AMER ASSOC CANCER RESEARCH 615 CHESTNUT ST, 17TH FLOOR, PHILADELPHIA, PA 19106-4404 USA},
	isbn = {0008-5472},
	author = {Peng, Xianghong and Mackey, Megan and Austin, Lauren and Oyelere, Adegboyega and Chen, Georgia and Huang, Xiaohua and El-Sayed, Mostafa A. and Shin, Dong M}
}
@article {1331,
	title = {Aggregation and Interaction of Cationic Nanoparticles on Bacterial Surfaces},
	journal = {Journal of the American Chemical Society},
	volume = {134},
	number = {16},
	year = {2012},
	note = {Times Cited: 1Hayden, Steven C. Zhao, Gengxiang Saha, Krishnendu Phillips, Ronnie L. Li, Xiaoning Miranda, Oscar R. Rotello, Vincent M. El-Sayed, Mostafa A. Schmidt-Krey, Ingeborg Bunz, Uwe H. F.},
	month = {Apr},
	pages = {6920-6923},
	abstract = {Cationic monolayer-protected gold nanoparticles (AuNPs) with sizes of 6 or 2 nm interact with the cell membranes of Escherichia coli (Gram-) and Bacillus subtilis (Gram+), resulting in the formation of strikingly distinct AuNP surface aggregation patterns or lysis depending upon the size of the AuNPs. The aggregation phenomena were investigated by transmission electron microscopy and UV-vis spectroscopy. Upon proteolytic treatment of the bacteria, the distinct aggregation patterns disappeared.},
	isbn = {0002-7863},
	doi = {10.1021/ja301167y},
	author = {Hayden, S. C. and Zhao, G. X. and Saha, K. and Phillips, R. L. and Li, X. N. and Miranda, O. R. and Rotello, V. M. and El-Sayed, M. A. and Schmidt-Krey, I. and Bunz, U. H. F.}
}
@article {1329,
	title = {Antiandrogen Gold Nanoparticles Dual-Target and Overcome Treatment Resistance in Hormone-Insensitive Prostate Cancer Cells},
	journal = {Bioconjugate Chemistry},
	volume = {23},
	number = {8},
	year = {2012},
	note = {Times Cited: 0Dreaden, Erik C. Gryder, Berkley E. Austin, Lauren A. Defo, Brice A. Tene Hayden, Steven C. Pi, Min Quarles, L. Darryl Oyelere, Adegboyega K. El-Sayed, Mostafa A.},
	month = {Aug},
	pages = {1507-1512},
	abstract = {prostate cancer is the most commonly diagnosed cancer among men in the developed countries.(1) One in six males in the U.S.(2) and one in nine males in the U.K.(3) will develop the disease at some point during their lifetime. Despite advances in prostate cancer screening, more than a quarter of a million men die from the disease every year(1) due primarily to treatment-resistance and metastasis. Colloidal nanotechnologies can provide tremendous enhancements to existing targeting/treatment strategies for prostate cancer to which malignant cells are less sensitive. Here, we show that antiandrogen gold nanoparticles-multivalent analogues of antiandrogens currently used in clinical therapy for prostate cancer-selectively engage two distinct receptors, androgen receptor (AR), a target for the treatment of prostate cancer, as well as a novel G-protein coupled receptor, GPRC6A, that is also upregulated in prostate cancer. These nanoparticles selectively accumulated in hormone-insensitive and chemotherapy resistant prostate cancer cells, bound androgen receptor with multivalent affinity, and exhibited greatly enhanced drug potency versus monovalent antiandrogens currently in clinical use Further, antiandrogen gold nanoparticles selectively stimulated GPRC6A with multivalent affinity, demonstrating that the delivery of nanoscale antiandrogens can also be facilitated by the transmembrane receptor in order to realize increasingly selective, increasingly potent therapy for treatment-resistant prostate cancers.},
	isbn = {1043-1802},
	doi = {10.1021/bc300158k},
	author = {Dreaden, E. C. and Gryder, B. E. and Austin, Lauren and Defo, B. A. T. and Hayden, S. C. and Pi, M. and Quarles, L. D. and Oyelere, A. K. and El-Sayed, M. A.}
}
@article {1341,
	title = {Extinction vs Absorption: Which Is the Indicator of Plasmonic Field Strength for Silver Nanocubes?},
	journal = {Journal of Physical Chemistry C},
	volume = {116},
	number = {43},
	year = {2012},
	note = {Times Cited: 0Near, Rachel Hayden, Steven El-Sayed, Mostafa},
	month = {Nov},
	pages = {23019-23026},
	abstract = {This investigation demonstrates the contributions of absorption and scattering to the extinction spectrum of silver nanocubes with multipole resonances and the complexity of the resulting plasmon field strengths for these varying modes. The three-dimensional plasmonic field distribution and orientation around a silver nanosphere (AgNS; 40 nm) and a silver nanocube (AgNC; 40, 60, 86 nm) were calculated in the visible via the discrete dipole approximation. The three-dimensional nature of these particles allows for significant contribution from the quadrupole mode in some cases. The AgNS displays one plasmon band, its dipole mode, and has little contribution from scattering. The maximum plasmon field occurs at the extinction maximum, as expected. The 40 nm AgNC exhibits multiple plasmon bands, and the highest maximum field strength is attained from excitation of the quadrupole mode, not the dipole mode. As the size of the AgNC increases, the contribution from scattering increases. When the contribution from scattering is greater than the contribution from absorption in a AgNC, the field strength within a plasmon mode trends with the absorption and not with the extinction or cattering. This should be considered in applications of AgNCs, as excitation of the largest peak in the experimental extinction spectrum will not always result in the strongest plasmon field strength.},
	isbn = {1932-7447},
	doi = {10.1021/jp309272b},
	author = {Near, R. and Hayden, S. and El-Sayed, M.}
}
@article {1326,
	title = {The golden age: gold nanoparticles for biomedicine},
	journal = {Chemical Society Reviews},
	volume = {41},
	number = {7},
	year = {2012},
	note = {Times Cited: 54Dreaden, Erik C. Alkilany, Alaaldin M. Huang, Xiaohua Murphy, Catherine J. El-Sayed, Mostafa A.},
	pages = {2740-2779},
	abstract = {Gold nanoparticles have been used in biomedical applications since their first colloidal syntheses more than three centuries ago. However, over the past two decades, their beautiful colors and unique electronic properties have also attracted tremendous attention due to their historical applications in art and ancient medicine and current applications in enhanced optoelectronics and photovoltaics. In spite of their modest alchemical beginnings, gold nanoparticles exhibit physical properties that are truly different from both small molecules and bulk materials, as well as from other nanoscale particles. Their unique combination of properties is just beginning to be fully realized in range of medical diagnostic and therapeutic applications. This critical review will provide insights into the design, synthesis, functionalization, and applications of these artificial molecules in biomedicine and discuss their tailored interactions with biological systems to achieve improved patient health. Further, we provide a survey of the rapidly expanding body of literature on this topic and argue that gold nanotechnology-enabled biomedicine is not simply an act of {\textquoteright}gilding the (nanomedicinal) lily{\textquoteright}, but that a new {\textquoteright}Golden Age{\textquoteright} of biomedical nanotechnology is truly upon us. Moving forward, the most challenging nanoscience ahead of us will be to find new chemical and physical methods of functionalizing gold nanoparticles with compounds that can promote efficient binding, clearance, and biocompatibility and to assess their safety to other biological systems and their long-term term effects on human health and reproduction (472 references).},
	isbn = {0306-0012},
	doi = {10.1039/c1cs15237h},
	author = {Dreaden, E. C. and Alkilany, A. M. and Huang, X. H. and Murphy, C. J. and El-Sayed, M. A.}
}
@article {1415,
	title = {The one dimensional photofragment translational spectroscopic technique: intramolecular clocking of energy redistribution for molecules falling apart1},
	journal = {Time-of-Flight Mass Spectrometry and its Applications},
	year = {2012},
	pages = {265},
	isbn = {0444596186},
	author = {Hwangl, Hyun Jin and Grifliths, Jennifer and El-Sayed, M. A.}
}
@article {1334,
	title = {The unusual fluorescence intensity enhancement of poly(p-phenyleneethynylene) polymer separated from the silver nanocube surface by H-bonded LbL shells},
	journal = {Journal of Materials Chemistry},
	volume = {22},
	number = {33},
	year = {2012},
	note = {Times Cited: 0Lisunova, Milana Mahmoud, Mahmoud Holland, Neal Combs, Zachary A. El-Sayed, Mostafa A. Tsukruk, Vladimir V.},
	pages = {16745-16753},
	abstract = {The fluorescence intensity of poly(p-phenyleneethynylene) (PPE) polymer separated from the surface of plasmonic silver nanocubes (47 nm AgNCs) is measured by varying the number of layers of polyvinyl pyrrolidone (PVPON) and polymethyl acrylic acid (PMAA), n. The shell thickness is sensitive to the solvent due to the formation of a solvent-sensitive hydrogen bonding network. The fluorescent behavior of the PPE on the core-shell PPE-(PVPON-PMAA) n-AgNCs structures fabricated here was evaluated as a function of n as well as the nature of the surrounding solvent. Surprisingly, the fluorescence intensity of the outer PPE shell is found to increase dramatically (by more than an order of magnitude) as its separation from the nanoparticle surface increases and then decreases at a distance that depends upon the swelling behavior of the polymer shells. The distance for the highest fluorescence enhancement was found to be 20.0 nm and 24.0 nm, in water and ethanol respectively. The observed change in the fluorescence intensity of the PPE polymer with increasing its separation from the plasmonic surface is proposed to result from the interplay between a short range quenching mechanism and a relatively long-range plasmonic fluorescence enhancing mechanism. DDA calculations gave support to the significant contribution of the latter mechanism.},
	isbn = {0959-9428},
	doi = {10.1039/c2jm32450d},
	author = {Lisunova, M. and Mahmoud, M. and Holland, N. and Combs, Z. A. and El-Sayed, M. A. and Tsukruk, V. V.}
}
@article {1081,
	title = {Electrochemical Fabrication of Strontium-Doped TiO(2) Nanotube Array Electrodes and Investigation of Their Photoelectrochemical Properties},
	journal = {Journal of Physical Chemistry C},
	volume = {115},
	number = {27},
	year = {2011},
	note = {Hamedani, Hoda A. Allam, Nageh K. Garmestani, Hamid El-Sayed, Mostafa A.},
	month = {Jul},
	pages = {13480-13486},
	abstract = {In recent years, considerable efforts have been made to improve the performance of photoactive nanostructured materials for water-splitting applications. Herein, we report on the fabrication and photoelectrochemical properties of highly ordered Sr-doped TiO(2) nanotube arrays synthesized via a one-step electrochemical anodization technique. Nanotube arrays of Sr-doped TiO(2) were synthesized via anodization of titanium foil in aqueous electrolytes containing NH(4)F and various concentrations of Sr(OH)(2) at different electrolyte pHs. The morphology and quality of the fabricated materials were found to be significantly affected by the pH of the electrolyte as well as the solubility limit of Sr(OH)(2) in the test electrolyte. The photoelectrochemical measurements revealed that Sr doping can significantly improve the photoconversion efficiency of the material. Using Sr-doped TiO(2) nanotube arrays, an electrode photoconversion efficiency of 0.69\% was obtained, which is more than 3 times higher than that of the undoped nanotube arrays (0.2\%) fabricated and tested under the same conditions.},
	isbn = {1932-7447},
	doi = {10.1021/jp201194b},
	author = {Hamedani, H. A. and Allam, N. K. and Garmestani, H. and El-Sayed, Mostafa A}
}
@article {1083,
	title = {Plasmonic Enhancement of Nonradiative Charge Carrier Relaxation and Proposed Effects from Enhanced Radiative Electronic Processes in Semiconductor-Gold Core-Shell Nanorod Arrays},
	journal = {Journal of Physical Chemistry C},
	volume = {115},
	number = {13},
	year = {2011},
	note = {Dreaden, Erik C. Neretina, Svetlana Qian, Wei El-Sayed, Mostafa A. Hughes, Robert A. Preston, John S. Mascher, Peter},
	month = {Apr},
	pages = {5578-5583},
	abstract = {Plasmonic field enhancement of nonradiative exciton relaxation rates in vertically aligned arrays of high aspect ratio CdTe-Au core-shell nanorods was investigated by transient absorption spectroscopy, computational electromagnetics, and kinetic modeling. Increasing shell thickness in the high aspect ratio nanorods was found to result in dramatic differences in polarization-dependent nonradiative exciton relaxation rates, which we attribute to differing mechanisms of plasmonic field enhancement associated with predominant ground- or excited-state absorption processes. These results are compared with previous investigations of low aspect ratio CdTe-Au core-shell nanorods, and overall conclusions regarding plasmonic enhancement of nonradiative relaxation rates in this system are presented. We propose that when the resonantly coupled dipolar plasmon field of the shell is polarized parallel to the ground-state absorption transition moment of the core, Auger recombination dominates carrier relaxation and slower second-order decay kinetics are observed. When contributions of the resonantly coupled plasmon field are nondipolar or orthogonal to the ground-state absorption transition moment of the core, excited-state absorption processes are believed to dominate and increasingly rapid first-order relaxation kinetics are observed. We find that these processes can vary greatly, depending on shell thickness and the orientation of the array, but are insensitive to aspect ratio. These investigations have significant implications in the design of photovoltaic and optoelectronic devices incorporating anisotropic plasmonic elements.},
	isbn = {1932-7447},
	doi = {10.1021/jp112129k},
	author = {Dreaden, Erik and Neretina, Svetlana and Qian, Wei and El-Sayed, Mostafa A and Hughes, Robert A and Preston, John S and Mascher, Peter}
}
@article {1079,
	title = {Plasmonic Spheroidal Metal Nanoshells Showing Larger Tunability and Stronger Near Fields Than Their Spherical Counterparts: An Effect of Enhanced Plasmon Coupling},
	journal = {Journal of Physical Chemistry Letters},
	volume = {2},
	number = {5},
	year = {2011},
	note = {Hooshmand, Nasrin Jain, Prashant K. El-Sayed, Mostafa A.},
	month = {Mar},
	pages = {374-378},
	abstract = {Two of the most tunable nanostructure geometries for nanoplas monics include the metal nanoshell structure and the spheroidal geometry. We systematically investigate the effect of combining both geometries within the same nanostructure. Localized surface plasmon resonances (LSPRs) of spheroidal gold nanoshells are simulated as a function of their aspect ratio. The long-axis LSPR mode of a spheroidal nanoshell red shifts with decreasing shell thickness, similar to a spherical nanoshell. A higher aspect ratio spheroidal nanoshell shows a larger fractional LSPR red shift for the same thickness normalized by core dimensions. This is because coupling between the inner and outer surface plasmons of the nanoshell is stronger for the elongated spheroidal geometry as compared to that for the spherical case, increasing in strength with increasing aspect ratio. It is the result of this enhanced plasmon coupling that spheroidal nanoshells of aspect ratio 4 are over two times more tunable than spherical nanoshells. Also, the plasmonic field enhancement is an order of magnitude larger for the spheroidal nanoshells of aspect ratio 4 as compared to spherical nanoshells. These effects observed in the spheroidal nanoshell are analogous to those in a dimer of spheroidal nanopatides.},
	isbn = {1948-7185},
	doi = {10.1021/jz200034j},
	author = {Hooshmand, N. and Jain, Prashant K and El-Sayed, Mostafa A}
}
@article {1080,
	title = {Self-Standing Crystalline TiO(2) Nanotubes/CNTs Heterojunction Membrane: Synthesis and Characterization},
	journal = {Acs Applied Materials \& Interfaces},
	volume = {3},
	number = {4},
	year = {2011},
	note = {Hesabi, Zohreh R. Allam, Nageh K. Dahmen, Klaus Garmestani, Hamid El-Sayed, Mostafa A.},
	month = {Apr},
	pages = {952-955},
	abstract = {In the present study, we report for the first time synthesis of TiO(2) nanotubes/CNTs heterojunction membrane. Chemical vapor deposition (CVD) of CNTs at 650 degrees C in a mixture of H(2)/He atmosphere led to in situ detachment of the anodically fabricated TiO(2) nanotube layers from the Ti substrate underneath. Morphological and structural evolution of TiO(2) nanotubes after CNTs deposition were investigated by field- emission scanning electron microscopy (FESEM), glancing angle X-ray diffraction (GAXRD), and X-ray photoelectron spectroscopy (XPS) analyses.},
	isbn = {1944-8244},
	doi = {10.1021/am200124p},
	author = {Hesabi, Z. R. and Allam, N. K. and Dahmen, K. and Garmestani, H. and El-Sayed, Mostafa A}
}
@article {1074,
	title = {Tailoring Plasmonic and Electrostatic Field Effects To Maximize Solar Energy Conversion by Bacteriorhodopsin, the Other Natural Photosynthetic System},
	journal = {Nano Letters},
	volume = {11},
	number = {9},
	year = {2011},
	note = {Yen, Chun-Wan Hayden, Steven C. Dreaden, Erik C. Szymanski, Paul El-Sayed, Mostafa A.},
	month = {Sep},
	pages = {3821-3826},
	abstract = {We have explored the plasmonic field enhancement of current production from bacteriorhodopsin (bR) by maximizing the blue light effect, where the influx of blue photons absorbed by the long-lived M intermediate drastically shortens the time scale of the bR photocycle, leading to current enhancement. To this end, we used three approaches in our solution-based cell: proton selective Nafion membrane. (2) We maximized the plasmonic surface (1) We improved the charge carrier separation in solution through the use of a field effects by selecting the capping polymer with minimum surface field screening and best nanopartide stability. (3) We selected the plasmonic nanoparticle with the strongest plasmonic field whose surface plasmon resonance has the largest spectral overlap with the blue light absorbing M-intermediate. Theoretical models are used to explain experimental results, which show a 40 nm cuboidal nanoparticle capped with 55k PVP polymer to give the best photocurrent enhancement. Enhanced by this particle, bR in our Nafion membrane solution cell gave a photocurrent of 0.21 mu A/cm(3), which is 5000 times larger than the published results for thin film bR electrochemical cells even with an applied bias. Additional possible enhancements are proposed.},
	isbn = {1530-6984},
	doi = {10.1021/nl2018959},
	author = {Yen, C. W. and Hayden, S. C. and Dreaden, Erik and Szymanski, P. and El-Sayed, Mostafa A}
}
@inbook {809,
	title = {Applications of gold nanorods for cancer imaging and photothermal therapy},
	booktitle = {Methods in Molecular Biology},
	volume = {624},
	year = {2010},
	pages = {343-357},
	publisher = {Springer},
	organization = {Springer},
	chapter = {23},
	abstract = {This chapter describes the application of gold nanorods in biomedical imaging and photothermal therapy.  The photothermal properties of gold nanorods are summarized and the synthesis as well as antibody conjugation of gold nanorods is outlined.  Biomedical applications of gold nanorods include cancer imaging using their enhanced scattering properties and photothermal therapy using their enhanced nonradioactive photothermal property.},
	keywords = {cancer, gold nanorods, imaging, photothermal therapy},
	isbn = {1064-3745},
	doi = {10.1007/978-1-60761-609-2_23},
	url = {http://dx.doi.org/10.1007/978-1-60761-609-2_23},
	author = {Huang, Xiaohua and El Sayed, I.H. and El-Sayed, Mostafa A and Grobmyer, SR}
}
@article {1097,
	title = {Comparative study of photothermolysis of cancer cells with nuclear-targeted or cytoplasm-targeted gold nanospheres: continuous wave or pulsed lasers},
	journal = {Journal of Biomedical Optics},
	volume = {15},
	number = {5},
	year = {2010},
	note = {Huang, Xiaohua Kang, Bin Qian, Wei Mackey, Megan A. Chen, Po C. Oyelere, Adegboyega K. El-Sayed, Ivan H. El-Sayed, Mostafa A.},
	month = {Sep-Oct},
	abstract = {We conduct a comparative study on the efficiency and cell death pathways of continuous wave (cw) and nanosecond pulsed laser photothermal cancer therapy using gold nanospheres delivered to either the cytoplasm or nucleus of cancer cells. Cytoplasm localization is achieved using arginine-glycine-aspartate peptide modified gold nanospheres, which target integrin receptors on the cell surface and are subsequently internalized by the cells. Nuclear delivery is achieved by conjugating the gold nanospheres with nuclear localization sequence peptides originating from the simian virus. Photothermal experiments show that cell death can be induced with a single pulse of a nanosecond laser more efficiently than with a cw laser. When the cw laser is applied, gold nanospheres localized in the cytoplasm are more effective in inducing cell destruction than gold nanospheres localized at the nucleus. The opposite effect is observed when the nanosecond pulsed laser is used, suggesting that plasmonic field enhancement of the nonlinear absorption processes occurs at high localization of gold nanospheres at the nucleus. Cell death pathways are further investigated via a standard apoptosis kit to show that the cell death mechanisms depend on the type of laser used. While the cw laser induces cell death via apoptosis, the nanosecond pulsed laser leads to cell necrosis. These studies add mechanistic insight to gold nanoparticle-based photothermal therapy of cancer. (c) 2010 Society of Photo-Optical Instrumentation Engineers. [DOI: 10.1117/1.3486538]},
	isbn = {1083-3668},
	doi = {10.1117/1.3486538},
	author = {Huang, Xiaohua and Kang, Bin and Qian, Wei and Mackey, M. A. and Chen, P. C. and Oyelere, A. K. and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {810,
	title = {Dark-field light scattering imaging of living cancer cell component from birth through division using bioconjugated gold nanoprobes},
	journal = {Journal of Biomedical Optics},
	volume = {15},
	year = {2010},
	pages = {046025},
	abstract = {Novel methods and technologies that could extend and complement the capabilities of the prevailing fluorescence microscope in following the cell cycle under different perturbations are highly desirable in the area of biological and biomedical imaging. We report a newly designed instrument for long-term light scattering live cell imaging based on integrating a homebuilt environmental cell incubation minichamber and an angled dark-field illumination system into a conventional inverted light microscope. Peptide-conjugated gold nanoparticles that are selectively delivered to either the cytoplasmic or nuclear region of the cell are used as light scattering contrast agents. The new system enables us to carry out continuous and intermittence-free dark-field live cell imaging over several tens of hours. A variety of applications of this imaging system are demonstrated, such as monitoring the nuclear uptake of peptide-conjugated gold nanoparticles, tracking the full cycle of cancer cells from birth to division, following the chromosome dynamics during cell mitosis, and observing the intracellular distribution of gold nanoparticles after cell division. We also discuss the overall effect of nuclear targeting gold nanoparticles on the cell viability of parent and daughter cells.},
	doi = {10.1117/1.3477179},
	url = {http://dx.doi.org/10.1117/1.3477179},
	author = {Qian, Wei and Huang, Xiaohua and Kang, Bin and El-Sayed, Mostafa A}
}
@inbook {816,
	title = {Fluorescent Quenching Gold Nanoparticles: Potential Biomedical Applications},
	booktitle = {Metal Enhanced Fluorescence},
	year = {2010},
	month = {06/2010},
	pages = {573-599},
	publisher = {Wiley Online Library},
	organization = {Wiley Online Library},
	chapter = {20},
	keywords = {biomedical applications, fluorescent quenching, gold nanoparticles, Raman spectroscopy, surface plasmon resonance},
	doi = {10.1002/9780470642795.ch20},
	url = {http://dx.doi.org/10.1002/9780470642795.ch20},
	author = {Huang, Xiaohua and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {808,
	title = {A Reexamination of Active and Passive Tumor Targeting by Using Rod-Shaped Gold Nanocrystals and Covalently Conjugated Peptide Ligands},
	journal = {ACS Nano},
	volume = {4},
	year = {2010},
	note = {doi: 10.1021/nn102055s},
	month = {2010},
	pages = {5887 - 5896},
	publisher = {American Chemical Society},
	abstract = {The targeted delivery of nanoparticles to solid tumors is one of the most important and challenging problems in cancer nanomedicine, but the detailed delivery mechanisms and design principles are still not well understood. Here we report quantitative tumor uptake studies for a class of elongated gold nanocrystals (called nanorods) that are covalently conjugated to tumor-targeting peptides. A major advantage in using gold as a ?tracer? is that the accumulated gold in tumors and other organs can be quantitatively determined by elemental mass spectrometry (gold is not a natural element found in animals). Thus, colloidal gold nanorods are stabilized with a layer of polyethylene glycols (PEGs) and are conjugated to three different ligands: (i) a single-chain variable fragment (ScFv) peptide that recognizes the epidermal growth factor receptor (EGFR); (ii) an amino terminal fragment (ATF) peptide that recognizes the urokinase plasminogen activator receptor (uPAR); and (iii) a cyclic RGD peptide that recognizes the av?3 integrin receptor. Quantitative pharmacokinetic and biodistribution data show that these targeting ligands only marginally improve the total gold accumulation in xenograft tumor models in comparison with nontargeted controls, but their use could greatly alter the intracellular and extracellular nanoparticle distributions. When the gold nanorods are administered via intravenous injection, we also find that active molecular targeting of the tumor microenvironments (e.g., fibroblasts, macrophages, and vasculatures) does not significantly influence the tumor nanoparticle uptake. These results suggest that for photothermal cancer therapy, the preferred route of gold nanorod administration is intratumoral injection instead of intravenous injection.The targeted delivery of nanoparticles to solid tumors is one of the most important and challenging problems in cancer nanomedicine, but the detailed delivery mechanisms and design principles are still not well understood. Here we report quantitative tumor uptake studies for a class of elongated gold nanocrystals (called nanorods) that are covalently conjugated to tumor-targeting peptides. A major advantage in using gold as a ?tracer? is that the accumulated gold in tumors and other organs can be quantitatively determined by elemental mass spectrometry (gold is not a natural element found in animals). Thus, colloidal gold nanorods are stabilized with a layer of polyethylene glycols (PEGs) and are conjugated to three different ligands: (i) a single-chain variable fragment (ScFv) peptide that recognizes the epidermal growth factor receptor (EGFR); (ii) an amino terminal fragment (ATF) peptide that recognizes the urokinase plasminogen activator receptor (uPAR); and (iii) a cyclic RGD peptide that recognizes the av?3 integrin receptor. Quantitative pharmacokinetic and biodistribution data show that these targeting ligands only marginally improve the total gold accumulation in xenograft tumor models in comparison with nontargeted controls, but their use could greatly alter the intracellular and extracellular nanoparticle distributions. When the gold nanorods are administered via intravenous injection, we also find that active molecular targeting of the tumor microenvironments (e.g., fibroblasts, macrophages, and vasculatures) does not significantly influence the tumor nanoparticle uptake. These results suggest that for photothermal cancer therapy, the preferred route of gold nanorod administration is intratumoral injection instead of intravenous injection.},
	isbn = {1936-0851},
	url = {http://dx.doi.org/10.1021/nn102055s},
	author = {Huang, Xiaohua and Peng, Xianghong and Wang, Yiqing and Wang, Yuxiang and Shin, Dong M and El-Sayed, Mostafa A and Nie, Shuming}
}
@article {1098,
	title = {TiO(2) Nanotube/CdS Hybrid Electrodes: Extraordinary Enhancement in the Inactivation of Escherichia coli},
	journal = {Journal of the American Chemical Society},
	volume = {132},
	number = {41},
	year = {2010},
	note = {Hayden, Steven C. Allam, Nageh K. El-Sayed, Mostafa A.},
	month = {Oct},
	pages = {14406-14408},
	abstract = {Titanium dioxide nanotubes offer distinct advantages over films of the same material in the production of hydroxyl radicals and subsequent inactivation of Escherichia coli in wastewater. However, their visible light absorption capabilities are limited. Semiconducting nanocrystals of cadmium sulfide have been used to increase the sensitivity of TiO(2) nanotubes to visible light. A small applied potential, using CdS-coated TiO(2) nanotube arrays, allowed for total inactivation of E. call in hitherto record short time.},
	isbn = {0002-7863},
	doi = {10.1021/ja107034z},
	author = {Hayden, S. C. and Allam, N. K. and El-Sayed, Mostafa A}
}
@article {1114,
	title = {The Dependence of the Plasmon Field Induced Nonradiative Electronic Relaxation Mechanisms on the Gold Shell Thickness in Vertically Aligned CdTe-Au Core-Shell Nanorods},
	journal = {Nano Letters},
	volume = {9},
	number = {11},
	year = {2009},
	note = {Neretina, Svetlana Dreaden, Erik C. Qian, Wei El-Sayed, Mostafa A. Hughes, Robert A. Preston, John S. Mascher, Peter},
	month = {Nov},
	pages = {3772-3779},
	abstract = {The dependence of the plasmon field enhancement of the nonradiative relaxation rate of the band gap electrons in vertically aligned CdTe-Au core-shell nanorods on the plasmonic gold nanoshell thickness is examined. Increasing the thickness of the gold nanoshell from 15 to 26 nm is found to change the decay curve from being nonexponential and anisotropic to one that is fully exponential and isotropic (i.e., independent of the nanorod orientation with respect to the exciting light polarization direction). Analysis of the kinetics of the possible electronic relaxation enhancement mechanisms is carried out, and DDA simulated properties of the induced plasmonic field of the thin and thick gold nanoshells are determined. On the basis of the conclusions of these treatments and the experimental results, it is concluded that by increasing the nanoshell thickness the relaxation processes evolve from multiple enhancement mechanisms, dominated by highly anisotropic Auger processes, to mechanism(s) involving first-order excited electron ejection process(es). The former is shown to give rise to nonexponential anisotropic decays in the dipolar plasmon field of the thin nanoshell, while the latter exhibits an exponential isotropic decay in the unpolarized plasmonic field of the thick nanoshell.},
	isbn = {1530-6984},
	doi = {10.1021/nl901960w},
	author = {Neretina, Svetlana and Dreaden, Erik and Qian, Wei and El-Sayed, Mostafa A and Hughes, Robert A and Preston, John S and Mascher, Peter}
}
@article {1113,
	title = {Exciton Lifetime Tuning by Changing the Plasmon Field Orientation with Respect to the Exciton Transition Moment Direction: CdTe-Au Core-Shell Nanorods},
	journal = {Nano Letters},
	volume = {9},
	number = {3},
	year = {2009},
	note = {Neretina, Svetlana Qian, Wei Dreaden, Erik C. El-Sayed, Mostafa A. Hughes, Robert A. Preston, John S. Mascher, Peter},
	month = {Mar},
	pages = {1242-1248},
	abstract = {We studied the anisotropy of the influence of plasmonic fields, arising from the optical excitation of a gold nanoshell plasmon absorption at 770 nm, on the lifetime of the bandgap state of the CdTe core in vertically aligned CdTe-Au core-shell nanorods. The previously observed decrease in the lifetime was studied as a function of the tilt angle between the long axis of the nanorod and the electric field polarization direction of the plasmon inducing exciting light. It is observed that the strongest enhancement to the exciton relaxation rate occurs when the two axes are parallel to one another. These results are discussed in terms of the coupling between the exciton transition moment of the CdTe rod and the electric field polarization direction of the gold nanoshell plasmon at 770 nm, which was determined from theoretical modeling based on the discrete dipole approximation.},
	isbn = {1530-6984},
	doi = {10.1021/nl900183m},
	author = {Neretina, Svetlana and Qian, Wei and Dreaden, Erik and El-Sayed, Mostafa A and Hughes, Robert A and Preston, John S and Mascher, Peter}
}
@article {1119,
	title = {Gold Nanoparticles Surface Plasmon Field Effects on the Proton Pump Process of the Bacteriorhodopsin Photosynthesis},
	journal = {Journal of the American Chemical Society},
	volume = {131},
	number = {7},
	year = {2009},
	note = {Biesso, Arianna Qian, Wei Huang, Xiaohua El-Sayed, Mostafa A.},
	month = {Feb},
	pages = {2442-+},
	abstract = {The rate of the proton pump of bacteriorhodopsin photosynthetic system is examined in the presence of a gold nanorod plasmon field. It is found that while the rate of the proton dissociation from the protonated Schiff base is not affected, the rate of its reprotonation increases. These results are qualitatively discussed in terms of several possible mechanisms.},
	isbn = {0002-7863},
	doi = {10.1021/ja8088873},
	author = {Biesso, A. and Qian, Wei and Huang, Xiaohua and El-Sayed, Mostafa A}
}
@article {1117,
	title = {Gold Nanorods: From Synthesis and Properties to Biological and Biomedical Applications},
	journal = {Advanced Materials},
	volume = {21},
	number = {48},
	year = {2009},
	note = {Huang, Xiaohuo Neretina, Svetiana El-Sayed, Mostafa A.},
	month = {Dec},
	pages = {4880-4910},
	abstract = {Noble metal nanoparticles; are capable of confining resonant photons in such a manner as to induce coherent surface plasmon oscillation of their conduction band electrons, a phenomenon leading to two important properties. Firstly, the confinement of the photon to the nanoparticle{\textquoteright}s dimensions leads to a large increase in its electromagnetic field and consequently great enhancement of all the nanoparticle{\textquoteright}s radiative properties, such as absorption and scattering. Moreover, by confining the photon{\textquoteright}s wavelength to the nanoparticle{\textquoteright}s small dimensions, there exists enhanced imaging resolving powers, which extend well below the diffraction limit, a property of considerable importance in potential device applications. Secondly, the strongly absorbed light by the nanoparticles is followed by a rapid dephasing of the coherent electron motion in tandem with an equally rapid energy transfer to the lattice, a process integral to the technologically relevant photothermal properties of plasmonic nanoparticles. Of all the possible nanoparticle shapes, gold nanorods are especially intriguing as they offer strong plasmonic fields while exhibiting excellent tunability and biocompatibility. We begin this review of gold nanorods by summarizing their radiative and nonradiative properties. Their various synthetic methods are then outlined with an emphasis on the seed-mediated chemical growth. In particular, we describe nanorod spontaneous self-assembly, chemically driven assembly, and polymer-based alignment. The final section details current studies aimed at applications in the biological and biomedical fields.},
	isbn = {0935-9648},
	doi = {10.1002/adma.200802789},
	author = {Huang, Xiaohua and Neretina, Svetlana and El-Sayed, Mostafa A}
}
@article {1128,
	title = {Gigahertz optical modulation resulting from coherent lattice oscillations induced by femtosecond laser pumping of 2D photonic crystals of gold-capped polystyrene microspheres},
	journal = {Advanced Materials},
	volume = {20},
	number = {4},
	year = {2008},
	note = {Huang, Wenyu Qian, Wei El-Sayed, Mostafa A.},
	month = {Feb},
	pages = {733-+},
	abstract = {A gigahertz all-optical modulation technique, based on a mechanism in which the modulation of the transmitted light is caused by the coherent oscillation of the phonon modes of gold caps on periodic polystyrene sphere monolayer arrays, is demonstrated. The modulation frequency can be tuned by changing the size of the polystyrene spheres.},
	isbn = {0935-9648},
	doi = {10.1002/adma.200701543},
	author = {Huang, Wenyu and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1131,
	title = {Gold nanorod assisted near-infrared plasmonic photothermal therapy (PPTT) of squamous cell carcinoma in mice},
	journal = {Cancer Letters},
	volume = {269},
	number = {1},
	year = {2008},
	note = {Dickerson, Erin B. Dreaden, Erik C. Huang, Xiaohua El-Sayed, Ivan H. Chu, Hunghao Pushpanketh, Sujatha McDonald, John F. El-Sayed, Mostafa A.},
	month = {Sep},
	pages = {57-66},
	abstract = {Plasmonic photothermal therapy (PPTT) is a minimally-invasive oncological treatment strategy in which photon energy is selectively administered and converted into heat sufficient to induce cellular hyperthermia. The present work demonstrates the feasibility of in vivo PPTT treatment of deep-tissue malignancies using easily-prepared plasmonic gold nanorods and a small, portable, inexpensive near-infrared (NIR) laser. Dramatic size decreases in squamous cell carcinoma xenografts were observed for direct (P < 0.0001) and intravenous (P < 0.0008) administration of pegylated gold nanorods in nu/nu mice. Inhibition of average tumor growth for both delivery methods was observed over a 13-day period, with resorption of >57\% of the directly-injected tumors and 25\% of the intravenously-treated tumors. Published by Elsevier Ltd.},
	isbn = {0304-3835},
	doi = {10.1016/j.canlet.2008.04.026},
	author = {Dickerson, E. B. and Dreaden, Erik and Huang, Xiaohua and El Sayed, I.H. and Chu, H. H. and Pushpanketh, S. and McDonald, J. F. and El-Sayed, Mostafa A}
}
@article {1124,
	title = {Noble Metals on the Nanoscale: Optical and Photothermal Properties and Some Applications in Imaging, Sensing, Biology, and Medicine},
	journal = {Accounts of Chemical Research},
	volume = {41},
	number = {12},
	year = {2008},
	note = {Jain, Prashant K. Huang, Xiaohua El-Sayed, Ivan H. El-Sayed, Mostafa A.},
	month = {Dec},
	pages = {1578-1586},
	abstract = {Noble metal nanostructures attract much interest because of their unique properties, including large optical field enhancements resulting in the strong scattering and absorption of light. The enhancement in the optical and photothermal properties of noble metal nanoparticles arises from resonant oscillation of their free electrons in the presence of light, also known as localized surface plasmon resonance (LSPR). The plasmon resonance can either radiate light (Mie scattering), a process that finds great utility in optical and imaging fields, or be rapidly converted to heat (absorption); the latter mechanism of dissipation has opened up applications in several new areas. The ability to integrate metal nanoparticles into biological Systems has had greatest impact in biology and biomedicine. In this Account we discuss the plasmonic properties of gold and silver nanostructures and present examples of how they are being utilized for biodiagnostics, biophysical studies, and medical therapy. For instance, taking advantage of the strong LSPR scattering of gold nanoparticles conjugated with specific targeting molecules allows the mollecule-specific imaging and diagnosis of diseases such as cancer. We emphasize in particular how the unique tunability of the plasmon resonance properties of metal nanopartides through variation of their size, shape, composition, and medium allows chemists to design nanostructures geared for specific bio-applications. We discuss some interesting nanostructure geometries, including nanorods, nanoshells, and nanopartide pairs, that exhibit dramatically enhanced and tunable plasmon resonances, making them highly suitable for bio-applications. Tuning the nanostructure shape (e.g., nanoprisms, nanorods, or nanoshells) is another means of enhancing the sensitivity of the LSPR to the nanopartide environment and, thereby, designing effective biosensing agents. Metal nanopartide pairs or assemblies display distance-dependent plasmon resonances as a result of field coupling. A universal scaling model, relating the plasmon resonance frequency to the interpartide distance in terms of the particle size, becomes potentially useful for measuring nanoscale distances (and their changes) in biological systems. The strong plasmon absorption and photothermal conversion of gold nanoparticles has been exploited in cancer therapy through the selective localized photothermal heating of cancer cells. For nanorods or nanoshells, the LSPR can be tuned to the near-infrared region, making it possible to perform in vivo imaging and therapy. The examples of the applicators of noble metal nanostructures provided herein can be readily generalized to other areas of biology and medicine because plasmonic nanomaterials exhibit great range, versatility, and systematic tunability of their optical attributes.},
	isbn = {0001-4842},
	doi = {10.1021/ar7002804},
	author = {Jain, Prashant K and Huang, Xiaohua and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {1129,
	title = {Photothermally excited coherent lattice phonon oscillations in plasmonic nanoparticles},
	journal = {European Physical Journal-Special Topics},
	volume = {153},
	year = {2008},
	note = {Huang, W. El-Sayed, M. A.14th International Conference on Photoacoustic and Photothermal Phenomena/1st US-Egypt Workshop on Photoacoustic and Photothermal PhenomenaJan 07-11, 2007Cairo, EGYPT},
	month = {Jan},
	pages = {325-333},
	abstract = {The photothermal property of (Ag and Au) plasmonic nanoparticles has brought about many important discoveries and applications in nanoscience and nanotechnology. In this review, we briefly summarize a photothermal effect, the coherent phonon oscillation, of plasmonic nanoparticles irradiated with ultrafast laser pulses of low power density. The coherent phonon oscillation is created in the nanoparticle by the ultrafast impulsive photothermal heating. The effects of size, shape, thickness, and interparticle interaction on the period of coherent phonon oscillations are discussed. The detection of the coherent lattice oscillation of metallic nanoparticles provides a powerful tool to characterize the mechanical and structural properties of nanostructures.},
	isbn = {1951-6355},
	doi = {10.1140/epjst/e2008-00456-x},
	author = {Huang, Wenyu and El-Sayed, Mostafa A}
}
@article {811,
	title = {Plasmon Field Effects on the Nonradiative Relaxation of Hot Electrons in an Electronically Quantized System: CdTe-Au Core-Shell Nanowires},
	journal = {Nano Letters},
	volume = {8},
	year = {2008},
	note = {doi: 10.1021/nl801303g},
	month = {2008},
	pages = {2410 - 2418},
	publisher = {American Chemical Society},
	abstract = {The intense electromagnetic fields of plasmonic nanoparticles, resulting from the excitation of their localized surface plasmon oscillations, are known to enhance radiative processes. Their effect on the nonradiative electronic processes, however, is not as well-documented. Here, we report on the enhancement of the nonradiative electronic relaxation rates in CdTe nanowires upon the addition of a thin gold nanoshell, especially at excitation energies overlapping with those of the surface plasmon oscillations. Some possible mechanisms by which localized surface plasmon fields can enhance nonradiative relaxation processes of any quantized electronic excitations are proposed.The intense electromagnetic fields of plasmonic nanoparticles, resulting from the excitation of their localized surface plasmon oscillations, are known to enhance radiative processes. Their effect on the nonradiative electronic processes, however, is not as well-documented. Here, we report on the enhancement of the nonradiative electronic relaxation rates in CdTe nanowires upon the addition of a thin gold nanoshell, especially at excitation energies overlapping with those of the surface plasmon oscillations. Some possible mechanisms by which localized surface plasmon fields can enhance nonradiative relaxation processes of any quantized electronic excitations are proposed.},
	isbn = {1530-6984},
	doi = {10.1021/nl801303g},
	url = {http://dx.doi.org/10.1021/nl801303g},
	author = {Neretina, Svetlana and Qian, Wei and Dreaden, Erik and El-Sayed, Mostafa A and Hughes, Robert A and Preston, John S and Mascher, Peter}
}
@article {1127,
	title = {Plasmonic photothermal therapy (PPTT) using gold nanoparticles},
	journal = {Lasers in Medical Science},
	volume = {23},
	number = {3},
	year = {2008},
	note = {Huang, Xiaohua Jain, Prashant K. El-Sayed, Ivan H. El-Sayed, Mostafa A.},
	month = {Jul},
	pages = {217-228},
	abstract = {The use of lasers, over the past few decades, has emerged to be highly promising for cancer therapy modalities, most commonly the photothermal therapy method, which employs light absorbing dyes for achieving the photothermal damage of tumors, and the photodynamic therapy, which employs chemical photosensitizers that generate singlet oxygen that is capable of tumor destruction. However, recent advances in the field of nanoscience have seen the emergence of noble metal nanostructures with unique photophysical properties, well suited for applications in cancer phototherapy. Noble metal nanoparticles, on account of the phenomenon of surface plasmon resonance, possess strongly enhanced visible and near-infrared light absorption, several orders of magnitude more intense compared to conventional laser phototherapy agents. The use of plasmonic nanoparticles as highly enhanced photoabsorbing agents has thus introduced a much more selective and efficient cancer therapy strategy, viz. plasmonic photothermal therapy (PPTT). The synthetic tunability of the optothermal properties and the bio-targeting abilities of the plasmonic gold nanostructures make the PPTT method furthermore promising. In this review, we discuss the development of the PPTT method with special emphasis on the recent in vitro and in vivo success using gold nanospheres coupled with visible lasers and gold nanorods and silica-gold nanoshells coupled with near-infrared lasers.},
	keywords = {display},
	isbn = {0268-8921},
	doi = {10.1007/s10103-007-0470-x},
	author = {Huang, Xiaohua and Jain, Prashant K and El Sayed, I.H. and El-Sayed, Mostafa A.}
}
@article {1130,
	title = {Pulsed laser photothermal annealing and ablation of plasmonic nanoparticles},
	journal = {European Physical Journal-Special Topics},
	volume = {153},
	year = {2008},
	note = {Huang, W. El-Sayed, M. A.14th International Conference on Photoacoustic and Photothermal Phenomena/1st US-Egypt Workshop on Photoacoustic and Photothermal PhenomenaJan 07-11, 2007Cairo, EGYPT},
	month = {Jan},
	pages = {223-230},
	abstract = {In this review, we briefly summarize the photothermal properties of plasmonic nanoparticles. Several photothermal effects of plasmonic nanoparticles irradiated with ultrafast laser pulses of various powers are introduced. Plasmonic nanoparticles have been synthesized by pulsed laser ablation of bulk materials. Melting and ablation of nanoparticles have also been used to modify the shape and the size distribution of plasmonic nanoparticle samples. Under certain circumstances, another interesting observation using high power femtosecond laser irradiation of plasmonic nanoparticles is also included in this review, namely the flying, by propulsion of the plasmonic nanoparticles.},
	isbn = {1951-6355},
	doi = {10.1140/epjst/e2008-00432-6},
	author = {Huang, Wenyu and El-Sayed, Mostafa A}
}
@article {1132,
	title = {Time-resolved investigation of the acoustic vibration of a single gold nanoprism pair},
	journal = {Journal of Physical Chemistry C},
	volume = {112},
	number = {30},
	year = {2008},
	note = {Burgin, J. Langot, P. Del Fatti, N. Vallee, F. Huang, W. El-Sayed, M. A.},
	month = {Jul},
	pages = {11231-11235},
	abstract = {The acoustic vibration of single gold nanoprism pairs on a glass substrate has been investigated in the time-domain combining a spatial modulation spectroscopy microscope with a high-sensitivity femtosecond pump-probe setup. Three modes were observed and ascribed to two in-plane and one out-of-plane vibration of the nanoprisms forming the pair, in agreement with a theoretical analysis. The periods of the two former modes with similar nature show weak (about 10\%) and well correlated pair to pair fluctuations that can be unambiguously ascribed to variation of the prism geometry. In contrast, strong fluctuations, by almost a factor of 6, of the mode damping are evidenced with no correlation with their period. This indicates large variations of the prism-substrate coupling, providing a unique way for its local investigation.},
	isbn = {1932-7447},
	doi = {10.1021/jp802365s},
	author = {Burgin, J. and Langot, P. and Del Fatti, N. and Vallee, F. and Huang, Wenyu and El-Sayed, Mostafa A}
}
@article {1141,
	title = {Cancer cells assemble and align gold nanorods conjugated to antibodies to produce highly enhanced, sharp, and polarized surface Raman spectra: A potential cancer diagnostic marker},
	journal = {Nano Letters},
	volume = {7},
	number = {6},
	year = {2007},
	note = {Huang, Xiaohua El-Sayed, Ivan H. Qian, Wei El-Sayed, Mostafa A.},
	month = {Jun},
	pages = {1591-1597},
	abstract = {Human oral cancer cells are found to assemble and align gold nanorods conjugated to anti-epidermal growth factor receptor (anti-EGFR) antibodies. Immnoconjugated gold nanorods and nanospheres were shown previously to exhibit strong Rayleigh (Mie) scattering useful for imaging. In the present letter, molecules near the nanorods on the cancer cells are found to give a Raman spectrum that is greatly enhanced (due to the high surface plasmon field of the nanorod assembly in which their extended surface plasmon fields overlap), sharp (due to a homogeneous environment), and polarized (due to anisotropic alignments). These observed properties can be used as diagnostic signatures for cancer cells.},
	isbn = {1530-6984},
	doi = {10.1021/nl070472c},
	author = {Huang, Xiaohua and El Sayed, I.H. and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1143,
	title = {The effect of plasmon field on the coherent lattice phonon oscillation in electron-beam fabricated gold nanoparticle pairs},
	journal = {Nano Letters},
	volume = {7},
	number = {10},
	year = {2007},
	note = {Huang, Wenyu Qian, Wei Jain, Prashant K. El-Sayed, Mostafa A.},
	month = {Oct},
	pages = {3227-3234},
	abstract = {By using electron beam lithography, we fabricated pairs of gold nanoparticles with varying interparticle separation. Double-beam femtosecond transient absorption spectroscopy was used to determine the coherent lattice oscillation frequency as a function of the interparticle separation in the presence of the plasmon field excited by the monitoring probe light. We found that the fractional shift in the coherent lattice phonon oscillation frequency follows an exponential decay with respect to the interparticle gap scaled by the disc diameter with the same decay constant as that previously observed for the fractional shift in the surface plasmon electronic oscillation resonance frequency. This strongly suggests that it is the near-field coupling between the particles that shifts both the coherent electronic oscillation (plasmon) frequency and the coherent lattice oscillation (phonon) frequency. The similar trend in the effect of interparticle coupling on the plasmon frequency and the phonon frequency is essentially a reflection of the universal scaling behavior of the distance decay of the interparticle plasmonic near-field. It is shown that the observed decrease in the lattice oscillation frequency with decrease in the interparticle distance is the result of a reduction in the effective free electron density within each nanoparticle pair partner as a result of the polarizing perturbation of the plasmonic field of the other nanoparticle in the pair.},
	isbn = {1530-6984},
	doi = {10.1021/nl071813p},
	author = {Huang, Wenyu and Qian, Wei and Jain, Prashant K and El-Sayed, Mostafa A}
}
@article {1145,
	title = {Effect of plasmonic gold nanoparticles on benign and malignant cellular autofluorescence: A novel probe for fluorescence based detection of cancer},
	journal = {Technology in Cancer Research \& Treatment},
	volume = {6},
	number = {5},
	year = {2007},
	note = {El-Sayed, Ivan Huang, Xiaohua Macheret, Fima Humstoe, Joseph Oren Kramer, Randall El-Sayed, Mostafa},
	month = {Oct},
	pages = {403-412},
	abstract = {Due to the strong surface fields of noble metal nanoparticles, absorption and scattering of electromagnetic radiation is greatly enhanced. Noble metallic nanoparticles represent potential novel optical probes for simultaneous molecular imaging and photothermal cancer therapy using the enhanced scattering and absorption of light. Further, gold nanoparticles can affect molecular fluorescence via chemical, electronic, or photonic interactions. Live cells generate fluorescence due to intracellular and extracellular molecules. Differences in the biochemical composition between healthy and malignant cells can be exploited in vivo to help identify cancer spectroscopically. The interaction of gold nanoparticles with cellular autofluorescence has not yet been characterized. We hypothesized that gold nanoparticles delivered to live cells in vitro would alter cellular autofluorescence and may be useful as a novel class of contrast agent for fluorescence based detection of cancer. The fluorescence of two fluorophores that are responsible for tissue autofluorescence, NADH and collagen, and of two oral squamous carcinoma cell lines and one immortalized benign epithelial cell line were measured in vitro. Gold nanoparticles of different shapes, both spheres and rods, quenched the fluorescence of the soluble NADH and collagen. Reduction of NADH fluorescence was due to oxidation of NADH to NAD+ catalyzed by gold nanoparticles (results we previously published). Reduction of collagen fluorescence appears due to photonic absorption of light. Furthermore, a mean quenching of 12/8\% (p < 0.00050) of the tissue autofluorescence of cell suspensions was achieved in this model when nanospheres were incubated with the live cells. Gold nanospheres significantly decrease cellular autofluorescence of live cells under physiological conditions when excited at 280nm. This is the first report to our knowledge to suggest the potential of developing targeted gold nanoparticles optical probes as contrast agents for fluorescence based diagnoses of cancer.},
	isbn = {1533-0346},
	author = {El Sayed, I.H. and Huang, Xiaohua and Macheret, F. and Humstoe, J. O. and Kramer, R. and El-Sayed, Mostafa A}
}
@article {1144,
	title = {Effect of the lattice crystallinity on the electron-phonon relaxation rates in gold nanoparticles},
	journal = {Journal of Physical Chemistry C},
	volume = {111},
	number = {29},
	year = {2007},
	note = {Huang, Wenyu Qian, Wei El-Sayed, Mostafa A. Ding, Yong Wang, Zhong Lin},
	month = {Jul},
	pages = {10751-10757},
	abstract = {In order to study the importance of surface phonons on the electron-phonon relaxation in plasmonic nanoparticles, the effect of size, shape, and materials have recently been studied. Gold and silver nanoparticles have shown no dependence on size and shape while copper nanoparticles have shown some size dependence. This suggests that the bulk phonons, which are sensitive to the bulk-phase structure, are solely responsible for the relaxation of the hot electron in gold and silver plasmonic nanoparticles. The importance of bulk phonons should depend on the degree of crystallinity. In the present study, we have found that the electron-phonon relaxation rate decreases greatly when polycrystalline prismatic gold nanoparticles are annealed and transformed into nearly single-crystalline nanospheres. The results are explained by the presence of high-density grain boundaries with dense, high-frequency molecular type vibrations which are effective in removing the energy of the excited electrons in the polycrystalline prismatic nanoparticles.},
	isbn = {1932-7447},
	doi = {10.1021/jp0738917},
	author = {Huang, Wenyu and Qian, Wei and El-Sayed, Mostafa A and Ding, Y. and Wang, Z.L.}
}
@article {1140,
	title = {Gold nanoparticles: interesting optical properties and recent applications in cancer diagnostic and therapy},
	journal = {Nanomedicine},
	volume = {2},
	number = {5},
	year = {2007},
	note = {Huang, Xiaohua Jain, Prashant K. El-Sayed, Ivan H. El-Sayed, Mostafa A.},
	month = {Oct},
	pages = {681-693},
	abstract = {Recent years have seen tremendous progress in the design and study of nanomaterials geared towards biological and biomedical applications, most notable among these being the noble metal nanoparticles. In this review, we outline the surface-plasmon resonance-enhanced optical properties of colloidal gold nanoparticles directed towards recent biomedical applications with an emphasis on cancer diagnostics and therapeutics. Methods of molecular-specific diagnostics/detection of cancer, including strongly enhanced surface plasmon resonance light-scattering, surface-enhanced emission of gold nanorods and surf ace-enhanced Raman scattering, are described. We also discuss the plasmonic photothermal therapy of cancer achieved by using the strongly enhanced surface-plasmon resonance absorption of gold nanospheres and nanorods.},
	isbn = {1743-5889},
	doi = {10.2217/17435889.2.5.681},
	author = {Huang, Xiaohua and Jain, Prashant K and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {1294,
	title = {Multicolorimetric plasmonic gold nanoparticles for 8 optical detection of oral squamous carcinoma},
	journal = {Oral Oncology},
	volume = {43},
	year = {2007},
	note = {El-Sayed, I. Huang, X. El-Sayed, M.1st World Congress of the International-Academy-of-Oral-OncologyMay 17-20, 2007Amsterdam, NETHERLANDSInt Acad Oral OncolS},
	month = {05/2007},
	pages = {121-121},
	issn = {1368-8375},
	author = {El Sayed, I.H. and Huang, X. and El-Sayed, Mostafa A}
}
@article {1135,
	title = {Peptide-conjugated gold nanorods for nuclear targeting},
	journal = {Bioconjugate Chemistry},
	volume = {18},
	number = {5},
	year = {2007},
	note = {Oyelere, Adegboyega K. Chen, Po C. Huang, Xiaohua El-Sayed, Ivan H. El-Sayed, Mostafa A.},
	month = {Sep-Oct},
	pages = {1490-1497},
	abstract = {Resonant electron oscillations on the surface of noble metal nanoparticles (Au, Ag, Cu) create the surface plasmon resonance (SPR) that greatly enhances the absorption and Rayleigh (Mie) scattering of light by these particles. By adjusting the size and shape of the particles from spheres to rods, the SPR absorption and scattering can be tuned from the visible to the near-infrared region (NIR) where biologic tissues are relatively transparent. Further, gold nanorods greatly enhance surface Raman scattering of adsorbed molecules. These unique properties make gold nanorods especially attractive as optical sensors for biological and medical applications. In the present work, gold nanorods are covalently conjugated with a nuclear localization signal peptide through a thioalkyl-triazole linker and incubated with an immortalized benign epithelial cell line and an oral cancer cell line. Dark field light SPR scattering images demonstrate that nanorods are located in both the cytoplasm and nucleus of both cell lines. Single cell micro-Raman spectra reveal enhanced Raman bands of the peptide as well as molecules in the cytoplasm and the nucleus. Further, the Raman spectra reveal a difference between benign and cancer cell lines. This work represents an important step toward both imaging and Raman-based intracellular biosensing with covalently linked ligand-nanorod probes.},
	isbn = {1043-1802},
	doi = {10.1021/bc070132i},
	author = {Oyelere, A. K. and Chen, P. C. and Huang, Xiaohua and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {1142,
	title = {The potential use of the enhanced nonlinear properties of gold nanospheres in photothermal cancer therapy},
	journal = {Lasers in Surgery and Medicine},
	volume = {39},
	number = {9},
	year = {2007},
	note = {Huang, Xiaohua Qian, Wei El-Sayed, Ivan H. El-Sayed, Mostafa A.},
	month = {Oct},
	pages = {747-753},
	abstract = {Background and Objective: Laser photothermal therapy (PTT) is practiced at the moment using short laser pulses. The use of plasmonic nanoparticles as contrast agents can decrease the laser energy by using the optical property of the nanoparticles and improve the tumor selectivity by the molecular probes on the particle surface. In this study, we aim at selective and efficient PTT by exploiting the nonlinear optical properties of aggregated spherical gold nanoparticles conjugated to anti-epidermal growth factor receptor (anti-EGFR) antibodies using short NIR laser pulses. Study Design/Materials and Methods: Spherical gold nanoparticles are synthesized and conjugated to anti-EGFR antibodies to specifically target HSC oral cancer cells. The nanoparticles are characterized by micro-absorption spectra and dark field light scattering imaging. Photothermal destructions of control and nanoparticle treated cancer cells are carried out with a ferntosecond Ti:Sapphire laser at 800 nm with a pulse duration of 100 femtoseconds and repetition rate of 1 kHz. Results: The laser power threshold for the photothermal destruction of cells after the nanoparticle treatment is found to be 20 times lower than that required to destroy the cells in the normal PTT, that is, without nanoparticles. The number of destroyed cells is quadratically dependent on the laser power. The number of dead cells shows a nonlinear dependence on the concentration of gold nanoparticles that are specifically targeted to cancer cells. Conclusions: The energy threshold and selectivity of PTT can greatly benefit from the use of the plasmonic enhanced nonlinear optical processes of spherical gold nanoparticles conjugated to anti-EGFR antibodies. The quadratic dependence of the photothermal efficiency on the pulsed NIR laser power indicates a second harmonic generation or a two photon absorption process. The observed nonlinear dependence on the gold nanoparticle concentration suggests that aggregated nanospheres are responsible for the observed enhanced photothermal destruction of the cells.},
	isbn = {0196-8092},
	doi = {10.1002/lsm.20577},
	author = {Huang, Xiaohua and Qian, Wei and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {815,
	title = {Review of some interesting surface plasmon resonance-enhanced properties of noble metal nanoparticles and their applications to biosystems},
	journal = {Plasmonics},
	volume = {2},
	year = {2007},
	pages = {107-118},
	publisher = {Springer},
	abstract = {Noble metal, especially gold (Au) and silver (Ag) nanoparticles exhibit unique and tunable optical properties on account of their surface plasmon resonance (SPR). In this review, we discuss the SPR-enhanced optical properties of noble metal nanoparticles, with an emphasis on the recent advances in the utility of these plasmonic properties in molecular-specific imaging and sensing, photo-diagnostics, and selective photothermal therapy. The strongly enhanced SPR scattering from Au nanoparticles makes them useful as bright optical tags for molecular-specific biological imaging and detection using simple dark-field optical microscopy. On the other hand, the SPR absorption of the nanoparticles has allowed their use in the selective laser photothermal therapy of cancer. We also discuss the sensitivity of the nanoparticle SPR frequency to the local medium dielectric constant, which has been successfully exploited for the optical sensing of chemical and biological analytes. Plasmon coupling between metal nanoparticle pairs is also discussed, which forms the basis for nanoparticle assembly-based biodiagnostics and the plasmon ruler for dynamic measurement of nanoscale distances in biological systems.},
	isbn = {1557-1955},
	doi = {10.1007/s11468-007-9031-1},
	url = {http://dx.doi.org/10.1007/s11468-007-9031-1},
	author = {Jain, Prashant K and Huang, Xiaohua and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {1137,
	title = {On the universal scaling behavior of the distance decay of plasmon coupling in metal nanoparticle pairs: A plasmon ruler equation},
	journal = {Nano Letters},
	volume = {7},
	number = {7},
	year = {2007},
	note = {Jain, Prashant K. Huang, Wenyu El-Sayed, Mostafa A.},
	month = {Jul},
	pages = {2080-2088},
	abstract = {Localized surface plasmon resonances (LSPR) in lithographically fabricated gold (Au) nanodisc pairs are investigated using microabsorption spectroscopy and electrodynamic simulations. In agreement with previous work, we find that the fractional plasmon wavelength shift for polarization along the interparticle axis decays nearly exponentially with the interparticle gap. In addition, we find that the decay length is roughly about 0.2 in units of the particle size for different nanoparticle size, shape, metal type, or medium dielectric constant. The near-exponential distance decay and the interesting "universal" scaling behavior of interparticle plasmon coupling can be qualitatively explained on the basis of a dipolar-coupling model as being due to the interplay of two factors: the direct dependence of the single-particle polarizability on the cubic power of the particle dimension and the decay of the plasmonic near-field as the cubic power of the inverse distance. Using this universal scaling behavior, we are able to derive a "plasmon ruler equation" that estimates the interparticle separation between Au nanospheres in a biological system from the observed fractional shift of the plasmon band. We find good agreement of the interparticle separations estimated using this equation with the experimental observations of Reinhard et al.},
	isbn = {1530-6984},
	doi = {10.1021/nl071008a},
	author = {Jain, Prashant K and Huang, Wenyu and El-Sayed, Mostafa A}
}
@article {1153,
	title = {Cancer cell imaging and photothermal therapy in the near-infrared region by using gold nanorods},
	journal = {Journal of the American Chemical Society},
	volume = {128},
	number = {6},
	year = {2006},
	note = {Huang, XH El-Sayed, IH Qian, W El-Sayed, MA},
	month = {Feb},
	pages = {2115-2120},
	abstract = {Due to strong electric fields at the surface, the absorption and scattering of electromagnetic radiation by noble metal nanoparticles are strongly enhanced. These unique properties provide the potential of designing novel optically active reagents for simultaneous molecular imaging and photothermal cancer therapy. It is desirable to use agents that are active in the near-infrared (NIR) region of the radiation spectrum to minimize the light extinction by intrinsic chromophores in native tissue. Gold nanorods with suitable aspect ratios (length divided by width) can absorb and scatter strongly in the NIR region (650-900 nm). In the present work, we provide an in vitro demonstration of gold nanorods as novel contrast agents for both molecular imaging and photothermal cancer therapy. Nanorods are synthesized and conjugated to anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibodies and incubated in cell cultures with a nonmalignant epithelial cell line (HaCat) and two malignant oral epithelial cell lines (HOC 313 clone 8 and HSC 3). The anti-EGFR anti body-conjugated nanorods bind specifically to the surface of the malignant-type cells with a much higher affinity due to the overexpressed EGFR on the cytoplasmic membrane of the malignant cells. As a result of the strongly scattered red light from gold nanorods in dark field, observed using a laboratory microscope, the malignant cells are clearly visualized and diagnosed from the nonmalignant cells. It is found that, after exposure to continuous red laser at 800 nm, malignant cells require about half the laser energy to be photothermally destroyed than the nonmalignant cells. Thus, both efficient cancer cell diagnostics and selective photothermal therapy are realized at the same time.},
	keywords = {display},
	isbn = {0002-7863},
	doi = {10.1021/ja057254a},
	author = {Huang, Xiaohua and El Sayed, I.H. and Qian, Wei and El-Sayed, Mostafa A.}
}
@article {1152,
	title = {Determination of the minimum temperature required for selective photothermal destruction of cancer cells with the use of immunotargeted gold nanoparticles},
	journal = {Photochemistry and Photobiology},
	volume = {82},
	number = {2},
	year = {2006},
	note = {Huang, XH Jain, PK El-Sayed, IH El-Sayed, MA},
	month = {Mar-Apr},
	pages = {412-417},
	abstract = {Laser photothermal therapy of cancer with the use of gold nanoparticles immunotargeted to molecular markers on the cell surface has been shown to be an effective modality to selectively kill cancer cells at much lower laser powers than those needed for healthy cells. To elucidate the minimum light dosimetry required to induce cell death, photothermal destruction of two cancerous cell lines and a noncancerous cell line treated with antiepidermal growth factor receptor (anti-EGFR) anti body-conjugated gold nanoparticles is studied, and a numerical heat transport model is used to estimate the local temperature rise within the cells as a result of the laser heating of the gold nanoparticles. It is found that cell samples with higher nanoparticle loading require a lower incident laser power to achieve a certain temperature rise. Numerically estimated temperatures of 70-80 degrees C achieved by heating the gold particles agree well with the measured threshold temperature for destruction of the cell lines by oven heating and those measured in an earlier nanoshell method. Specific binding of anti-EGFR antibody to cancerous cells overexpressing EGFR selectively increases the gold nanoparticle loading within cancerous cells, thus allowing the cancerous cells to be destroyed at lower laser power thresholds than needed for the noncancerous cells. In addition, photothermal therapy using gold nanoparticles requires lower laser power thresholds than therapies using conventional dyes due to the much higher absorption coefficient of the gold nanoparticles.},
	isbn = {0031-8655},
	doi = {10.1562/2005-12-14-ra-754},
	author = {Huang, Xiaohua and Jain, Prashant K and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {1154,
	title = {Gold nanoparticles propulsion from surface fueled by absorption of femtosecond laser pulse at their surface plasmon resonance},
	journal = {Journal of the American Chemical Society},
	volume = {128},
	number = {41},
	year = {2006},
	note = {Huang, Wenyu Qian, Wei El-Sayed, Mostafa A.},
	month = {Oct},
	pages = {13330-13331},
	isbn = {0002-7863},
	doi = {10.1021/ja064328p},
	author = {Huang, Wenyu and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1158,
	title = {Selective laser photo-thermal therapy of epithelial carcinoma using anti-EGFR antibody conjugated gold nanoparticles},
	journal = {Cancer Letters},
	volume = {239},
	number = {1},
	year = {2006},
	note = {El-Sayed, Ivan H. Huang, Xiaohua El-Sayed, Mostafa A.},
	month = {Jul},
	pages = {129-135},
	abstract = {Efficient conversion of strongly absorbed light by plasmonic gold nanoparticles to heat energy and their easy bioconjugation suggest their use as selective photothermal agents in molecular cancer cell targeting. Two oral squamous carcinoma cell lines (HSC 313 and HOC 3 Clone 8) and one benign epithelial cell line (HaCaT) were incubated with anti-epithelial growth factor receptor (EGFR) antibody conjugated gold nanoparticles and then exposed to continuous visible argon ion laser at 514 nm. It is found that the malignant cells require less than half the laser energy to be killed than the benign cells after incubation with anti-EGFR antibody conjugated Au nanoparticles. No photothermal destruction is observed for all types of cells in the absence of nanoparticles at four times energy required to kill the malignant cells with anti-EGFR/Au conjugates bonded. An nanoparticles thus offer a novel class of selective photothermal agents using a CW laser at low powers. The potential of using this selective technique in molecularly targeted photothermal therapy in vivo is discussed (c) 2005 Elsevier Ireland Ltd. All rights reserved.},
	isbn = {0304-3835},
	doi = {10.1016/j.canlet.2005.07.035},
	author = {El Sayed, I.H. and Huang, Xiaohua and El-Sayed, Mostafa A}
}
@article {1155,
	title = {Using silica films and powders modified with benzophenone to photoreduce silver nanoparticles},
	journal = {Journal of Photochemistry and Photobiology a-Chemistry},
	volume = {181},
	number = {2-3},
	year = {2006},
	note = {Eustis, Susie Krylova, Galina Smirnova, Natalie Eremenko, Anna Tabor, Christopher Huang, Wenyu El-Sayed, Mostafa A.},
	month = {Jul},
	pages = {385-393},
	abstract = {Porous silica (SiO2 films and powders), modified with benzophenone (BP), facilitates the formation of stable sliver nanoparticles by taking advantage of the solid supported photosensitizer. The silica serves as a carrier for the BP into an aqueous solution and its subsequent removal. Benzophenone, bound to a silica film, was able to reduce silver ions to generate nanoparticles in solution, while silica powder with bound BP generates silver nanoparticles that are attracted to the silica. Silver nanoparticles are also fabricated in porous silica films by incorporating silver ions into the films before casting and then irradiating the film in a solution containing BP. From pH studies, it is concluded that the ketyl-radicals and anion-radicals of BP and IPA both take part in the reduction of silver ions. These synthetic studies provide a new photochemical reduction method by immobilizing the reactant on a silica surface allowing generation of silver nanoparticles in solution attached to powders or inside a film for catalytic applications or increased conductivity of silica films. (c) 2006 Elsevier B.V. All rights reserved.},
	isbn = {1010-6030},
	doi = {10.1016/j.jphotochem.2005.12.024},
	author = {Eustis, Susie and Krylova, G. and Smirnova, N. and Eremenko, A. and Tabor, C. E. and Huang, Wenyu and El-Sayed, Mostafa A}
}
@article {1171,
	title = {Gold nanoparticle formation from photochemical reduction of Au3+ by continuous excitation in colloidal solutions. A proposed molecular mechanism},
	journal = {Journal of Physical Chemistry B},
	volume = {109},
	number = {11},
	year = {2005},
	note = {Eustis, S Hsu, HY El-Sayed, MA},
	month = {Mar},
	pages = {4811-4815},
	abstract = {A photochemical reduction of Au3+ with continuous 250-400 nm excitation is studied in ethylene Zalycol, and poly (vinylpyrrolidone) (PVP) is used as a capping material. After the absorption of Au3+ disappears, excitation is stopped. The surface plasmon absorption of gold as well as the thermal reappearance of the Au3+ absorption are found to increase as a function of time. The rates of these changes are studied as a function of the mole fraction of ethylene glycol in water. Experimental results show that a small amount of ethylene glycol increases the formation of gold nanoparticles and decreases the reformation of the Au3+ absorption after irradiation. Increasing the glycol concentration first increases the rate of formation of gold nanoparticles to a maximum at a mole fraction 0.40. As the glycol concentration is further increased, the rate of formation of the gold nanoparticles and the rate of re-formation of Au3+ decrease. A mechanism is proposed that involves the reduction of the excited Au3+ to Au2+ by ethylene glycol. This is followed by the disproportionation of Au2+ to Au3+ and Au1+. Both the reduction of Au1+ by ethylene glycol and its disproportionation lead to the formation of Au-0, which upon nucleation and growth form An nanoparticles.},
	isbn = {1520-6106},
	doi = {10.1021/jp0441588},
	author = {Eustis, Susie and Hsu, H. Y. and El-Sayed, Mostafa A}
}
@article {1169,
	title = {Gold nanoparticles: Catalyst for the oxidation of NADH to NAD(+)},
	journal = {Journal of Photochemistry and Photobiology B-Biology},
	volume = {81},
	number = {2},
	year = {2005},
	note = {Huang, XH El-Sayed, IH Yi, XB El-Sayed, MA},
	month = {Nov},
	pages = {76-83},
	abstract = {Nicotinamide adenine dinucleotide is an important coenzyme involved in the production of ATP, the fuel of energy, in every cell. It alternates between the oxidized form NAD(+) and the reduced form dihydronicotinamide adenine dinucleotide (NADH) and serves as a hydrogen and electron carrier in the cellular respiratory processes. In the present work, the catalytic effect of gold nanoparticles on the oxidization of NADH to NAD(+) was investigated. The addition of gold nanoparticles was found to quench the NADH fluorescence intensities but had no effect on the fluorescence lifetime. This suggested that the fluorescence quenching was not due to coupling with the excited state, but due to changing the ground state of NADH. The intensity of the 340 nm absorption band of NADH was found to decrease while that of the 260 nm band of NAD+ was found to increase as the concentration of gold nanoparticles increased. This conversion reaction was further supported by nuclear magnetic resonance and mass spectroscopy. The effect of the addition of NADH was found to slightly red shift and increase the intensity of the surface plasmon absorption band of gold nanoparticles at 520 nm. This gives a strong support that the conversion of NADH to NAD(+) is occurring on the surface of the gold nanoparticles, i.e. NADH is surface catalyzed by the gold nanoparticles. The catalytic property of this important reaction might have important future applications in biological and medical fields. (c) 2005 Elsevier B.V. All rights reserved.},
	isbn = {1011-1344},
	doi = {10.1016/j.jphotobiol.2005.05.010},
	author = {Huang, Xiaohua and El Sayed, I.H. and Yi, X. B. and El-Sayed, Mostafa A}
}
@article {821,
	title = {The Optically Detected Coherent Lattice Oscillations in Silver and Gold Monolayer Periodic Nanoprism Arrays:  The Effect of Interparticle Coupling},
	journal = {The Journal of Physical Chemistry B},
	volume = {109},
	year = {2005},
	note = {doi: 10.1021/jp0526647},
	month = {2005},
	pages = {18881 - 18888},
	publisher = {American Chemical Society},
	abstract = {Using femtosecond transient spectroscopy, we studied the optically detected laser-induced coherent phonon oscillation of monolayers of periodic arrays of prismatic-shaped silver and gold nanoparticles, assembled by using the technique of nanosphere lithography. In this method, the same size of polystyrene sphere and the same vacuum conditions are used. Under these circumstances, the gold nanoprisms formed are found to have sharper tips than the corresponding silver nanoprisms. For both gold and silver nanoparticles, the surface plasmon absorption maximum is found to depend linearly on size. The coherent lattice oscillation periods are also found to depend linearly on size. However, although the observed dependence for the silver nanoparticle is found to follow the calculated dependence of a single particle on size (based on a one-dimensional standing wave model), the gold nanoparticle deviates from this model, and the deviation is found to increase with the size of the nanoparticles. This deviation can be explained by considering interparticle coupling. A simple interparticle lattice oscillating dipolar coupling model of the dimer is found to qualitatively account for both the sign and the size dependence of the deviation. The absence of this deviation in the silver nanoparticle arrays is blamed on the weak interparticle coupling due to their rounded tips and the possibility of oxidation of their surfaces.Using femtosecond transient spectroscopy, we studied the optically detected laser-induced coherent phonon oscillation of monolayers of periodic arrays of prismatic-shaped silver and gold nanoparticles, assembled by using the technique of nanosphere lithography. In this method, the same size of polystyrene sphere and the same vacuum conditions are used. Under these circumstances, the gold nanoprisms formed are found to have sharper tips than the corresponding silver nanoprisms. For both gold and silver nanoparticles, the surface plasmon absorption maximum is found to depend linearly on size. The coherent lattice oscillation periods are also found to depend linearly on size. However, although the observed dependence for the silver nanoparticle is found to follow the calculated dependence of a single particle on size (based on a one-dimensional standing wave model), the gold nanoparticle deviates from this model, and the deviation is found to increase with the size of the nanoparticles. This deviation can be explained by considering interparticle coupling. A simple interparticle lattice oscillating dipolar coupling model of the dimer is found to qualitatively account for both the sign and the size dependence of the deviation. The absence of this deviation in the silver nanoparticle arrays is blamed on the weak interparticle coupling due to their rounded tips and the possibility of oxidation of their surfaces.},
	isbn = {1520-6106},
	doi = {10.1021/jp0526647},
	url = {http://dx.doi.org/10.1021/jp0526647},
	author = {Huang, Wenyu and Qian, Wei and El-Sayed, Mostafa A}
}
@proceedings {817,
	title = {Optically detected coherent picosecond lattice oscillations in two dimensional arrays of gold nanocrystals of different sizes and shapes induced by femtosecond laser pulses},
	volume = {5927},
	year = {2005},
	pages = {592701},
	abstract = {The nanosphere lithography (NSL) technique is used to make periodic gold array of prismatic nanoparticles. We use the femtosecond time resolved double beam transient optical detection to determine the coherent lattice oscillation in gold nanoparticles. Coherent lattice oscillation is compared on gold nanoparticles of different sizes and shapes. The effect of changing shape on the oscillation period was studied. Different environmental effects on the coherent lattice oscillation are eliminated by measuring the oscillation of the prismatic shape before and after we anneal it to spherical shape of the same number of atoms. A large change in the oscillation period is observed which agrees with the calculated period using different equations for the corresponding shapes.},
	doi = {10.1117/12.620501},
	url = {http://dx.doi.org/10.1117/12.620501},
	author = {Huang, Wenyu and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1170,
	title = {Photothermal reshaping of prismatic Au nanoparticles in periodic monolayer arrays by femtosecond laser pulses},
	journal = {Journal of Applied Physics},
	volume = {98},
	number = {11},
	year = {2005},
	note = {Huang, WY Qian, W El-Sayed, MA},
	month = {Dec},
	abstract = {Prismatic gold nanoparticles in the periodic monolayer arrays prepared with nanosphere lithography technique can be reshaped with femtosecond laser pulses at different powers and wavelengths. As the power density of 400 nm femtosecond laser increases, the prismatic particle tips begin to round and the overall particle shape changes from a prism to a sphere with a tripodal intermediate. The formation of the tip-rounded nanoprisms is probably due to the dewetting properties of gold on quartz surface and the low melting temperature at the tips. The formation of the tripodal nanoparticles is attributed to the inhomogeneous heating and lattice rearrangement of the as-deposited nanoparticles to a metastable state, which is more stable than the prismatic shape but less stable than the spherical shape. With 800 nm femtosecond laser irradiation, only tip-rounded nanoprisms are observed and no spherical nanoparticles are formed at the laser powers used. This is most likely due to the blueshift of the plasmon absorption band for the transformed particles, so that they cannot absorb the required energy to overcome the barrier to make the spherical shape. With 700 nm femtosecond laser irradiation, the tip-rounded and the tripodal nanoparticles are formed and few spherical particles are observed at the higher laser power density. From the results of this work, it is shown that by changing the wavelength and power density of the femtosecond laser, one can control the final shape of the particles formed from the original prismatic nanoparticles.},
	isbn = {0021-8979},
	doi = {10.1063/1.2132515},
	author = {Huang, Wenyu and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1173,
	title = {Surface plasmon resonance scattering and absorption of anti-EGFR antibody conjugated gold nanoparticles in cancer diagnostics: Applications in oral cancer},
	journal = {Nano Letters},
	volume = {5},
	number = {5},
	year = {2005},
	note = {El-Sayed, IH Huang, XH El-Sayed, MA},
	month = {May},
	pages = {829-834},
	abstract = {Gold nanoparticles with unique optical properties may be useful as biosensors in living whole cells. Using a simple and inexpensive technique, we recorded surface plasmon resonance (SPR) scattering images and SPR absorption spectra from both colloidal gold nanoparticles and from gold nanoparticles conjugated to monoclonal anti-epidermal growth factor receptor (anti-EGFR) antibodies after incubation in cell cultures with a nonmalignant epithelial cell line (HaCaT) and two malignant oral epithelial cell lines (HOC 313 clone 8 and HSC 3). Colloidal gold nanoparticles are found in dispersed and aggregated forms within the cell cytoplasm and provide anatomic labeling information, but their uptake is nonspecific for malignant cells. The anti-EGFR antibody conjugated nanoparticles specifically and homogeneously bind to the surface of the cancer type cells with 600\% greater affinity than to the noncancerous cells. This specific and homogeneous binding is found to give a relatively sharper SPR absorption band with a red shifted maximum compared to that observed when added to the noncancerous cells. These results suggest that SPR scattering imaging or SPR absorption spectroscopy generated from antibody conjugated gold nanoparticles can be useful in molecular biosensor techniques for the diagnosis and investigation of oral epithelial living cancer cells in vivo and in vitro.},
	keywords = {display},
	isbn = {1530-6984},
	doi = {10.1021/nl050074e},
	author = {El Sayed, I.H. and Huang, Xiaohua and El-Sayed, Mostafa A.}
}
@article {1179,
	title = {Coherent vibrational oscillation in gold prismatic monolayer periodic nanoparticle arrays},
	journal = {Nano Letters},
	volume = {4},
	number = {9},
	year = {2004},
	note = {Huang, WY Qian, W El-Sayed, MA},
	month = {Sep},
	pages = {1741-1747},
	abstract = {We studied the ultrafast laser-induced coherent phonon oscillation in prismatic shaped gold nanoparticles assembled in monolayer periodic arrays by using the nanosphere lithographic technique. The amplitude and phase of the oscillation observed by ultrafast pump-probe transient spectroscopy is monitored as the wavelength of the dipolar surface plasmon absorption decreases. At a certain wavelength, the oscillation could not be observed. As the monitoring wavelength decreases further, the sign of the amplitude changes. From the wavelength at which the oscillation is not detected, the dependence of the absorption maxima on the size of the nanoparticles, the changes in the nanoparticle size are estimated during its oscillation. This large change in the size of the prismatic nanoparticle compared to the small change reported previously for the nanosphere oscillations is discussed.},
	isbn = {1530-6984},
	doi = {10.1021/nl048875p},
	author = {Huang, Wenyu and Qian, Wei and El-Sayed, Mostafa A}
}
@article {1180,
	title = {Eu3+ binding to europium-regenerated bacteriorhodopsin upon delipidation and monomerization},
	journal = {Febs Letters},
	volume = {562},
	number = {1-3},
	year = {2004},
	note = {Heyes, CD Reynolds, KB El-Sayed, MA},
	month = {Mar},
	pages = {207-210},
	abstract = {We have studied the effect of monomerization of the purple membrane lattice, as well as removal of 75\% of the lipids, on the binding properties of Eu3+ ions. We found that delipidation and monomerization do not cause the cations to lose their binding ability to the protein. This suggests that the three most strongly bound Eu3+ cations do not bind to the lipids, but directly bind to the protein. Furthermore, we found that delipidation actually causes a slight increase in the binding affinity. This is likely a result of reduced aggregation of europium-regenerated bacteriorhodopsin (bR) upon lipid removal causing more exposure of the binding sites to the Eu3+ cations. These results, taken with those from our previous publication [Heyes and El-Sayed, Biophys. J. 85 (2003) 426-434], might suggest that the cations remain bound upon delipidation of bR, but have no effect on the function. This is discussed with respect to the role of cations in the function of native bR. (C) 2004 Published by Elsevier B.V. on behalf of the Federation of European Biochemical Societies.},
	isbn = {0014-5793},
	doi = {10.1016/s0014-5793(04)00182-6},
	author = {Heyes, C D and Reynolds, K. B. and El-Sayed, Mostafa A}
}
@article {1183,
	title = {Model system for growing and quantifying Streptococcus pneumoniae biofilms in situ and in real time},
	journal = {Applied and Environmental Microbiology},
	volume = {70},
	number = {8},
	year = {2004},
	note = {Donlan, RM Piede, JA Heyes, CD Sanii, L Murga, R Edmonds, P El-Sayed, I El-Sayed, MA},
	month = {Aug},
	pages = {4980-4988},
	abstract = {Streptococcus pneumoniae forms biofilms, but little is known about its extracellular polymeric substances (EPS) or the kinetics of biofilm formation. A system was developed to enable the simultaneous measurement of cells and the EPS of biofilm-associated S. pneumoniae in situ over time. A biofilm reactor containing germanium coupons was interfaced to an attenuated total reflectance (ATR) germanium cell of a Fourier transform infrared (FTIR) laser spectrometer. Biofilm-associated cells were recovered from the coupons and quantified by total and viable cell count methods. ATR-FTIR spectroscopy of biofilms formed on the germanium internal reflection element (IRE) of the ATR cell provided a continuous spectrum of biofilm protein and polysaccharide (a measure of the EPS). Staining of the biofilms on the IRE surface with specific fluorescent probes provided confirmatory evidence for the biofilm structure and the presence of biofilm polysaccharides. Biofilm protein and polysaccharides were detected within hours after inoculation and continued to increase for the next 141 h. The polysaccharide band increased at a substantially higher rate than did the protein band, demonstrating increasing coverage of the IRE surface with biofilm polysaccharides. The biofilm total cell counts on germanium coupons stabilized after 21 h, at approximately 10(5) cells per cm(2), while viable counts decreased as the biofilm aged. This system is unique in its ability to detect and quantify biofilm-associated cells and EPS of S. pneumoniae over time by using multiple, corroborative techniques. This approach could prove useful for the study of biofilm processes of this or other microorganisms of clinical or industrial relevance.},
	isbn = {0099-2240},
	doi = {10.1128/aem.70.8.4980-4988.2004},
	author = {Donlan, R. M. and Piede, J. A. and Heyes, C D and Sanii, L. S. and Murga, R. and Edmonds, P. and El Sayed, I.H. and El-Sayed, Mostafa A}
}
@article {1187,
	title = {Medium effect on the electron cooling dynamics in gold nanorods and truncated tetrahedra},
	journal = {Advanced Materials},
	volume = {15},
	number = {5},
	year = {2003},
	note = {Link, S Hathcock, DJ Nikoobakht, B El-Sayed, MA},
	month = {Mar},
	pages = {393-+},
	abstract = {A study on the electron relaxation dynamics and thermal cooling of colloidal gold nanoparticles (see Figure) in air and water finds that the local energy exchange with the surrounding medium occurs on the picosecond time scale, comparable with the electron-phonon relaxation, while a slow heat dissipation by water ensures that the particles remain heated for hundreds of picoseconds.},
	isbn = {0935-9648},
	doi = {10.1002/adma.200390088},
	author = {Link, Stephan and Hathcock, D. J. and Nikoobakht, Babak and El-Sayed, Mostafa A}
}
@article {1184,
	title = {Propene hydrogenation over truncated octahedral Pt nanoparticles supported on alumina},
	journal = {Journal of Catalysis},
	volume = {214},
	number = {1},
	year = {2003},
	note = {Yoo, JW Hathcock, DJ El-Sayed, MA},
	month = {Feb},
	pages = {1-7},
	abstract = {Colloidal Pt nanoparticles synthesized by a 1 : 5 concentration ratio of K2PtCl4 to polyacrylate were loaded on nanoporous alumina using the impregnation method at room temperature. The deposited Pt particles, present on the external surfaces of the support, were characterized by transmission electron microscopy, which indicated predominantly truncated octahedral (TO) shapes with a mean diameter of 10 nm. Their catalytic performance in the hydrogenation of propene at 30-80 degreesC was studied as a test reaction. The initial rate, reaction order, rate constant, activation energy, and turnover frequency were determined. The activation energy was found to be 8.4 +/- 0.2 kcal/mol, which is slightly lower than results reported for other platinum systems (10-14 kcal/mol). The TO platinum nanoparticles have atom-high surface steps, ledges, and kinks, and these atomic-scale fine structures are expected to decrease the activation energy. The reactivity of the surface atoms in this nanoparticle is so high that above 50 degreesC side reactions leading to complete surface poisoning take place within a few minutes. The effect of the polymer concentration of the polyacrylate-capped TO Pt/Al2O3 on the hydrogenation catalytic activity was also investigated. (C) 2003 Elsevier Science (USA). All rights reserved.},
	isbn = {0021-9517},
	doi = {10.1016/s0021-9517(02)00136-7},
	author = {Yoo, J. W. and Hathcock, D. J. and El-Sayed, Mostafa A}
}
@article {841,
	title = {Proton transfer reactions in native and deionized bacteriorhodopsin upon delipidation and monomerization},
	journal = {Biophysical journal},
	volume = {85},
	year = {2003},
	pages = {426-434},
	publisher = {Elsevier},
	abstract = {We have investigated the role of the native lipids on bacteriorhodopsin (bR) proton transfer and their connection with the cation-binding role. We observe that both the efficiency of M formation and the kinetics of M rise and decay depend on the lipids and lattice but, as the lipids are removed, the cation binding is a much less important factor for the proton pumping function. Upon 75\% delipidation using 3-[(cholamidopropyl)dimethylammonio]-propanesulfonate (CHAPS), the M formation and decay kinetics are much slower than the native, and the efficiency of M formation is \~{}30\%{\textendash}40\% that of the native. Upon monomerization of bR by Trition X-100, the efficiency of M recovers close to that of the native (depending on pH), M formation is \~{}10 times faster, and M decay kinetics are comparable to native at pH 7. The same results on the M intermediate are observed if deionized blue bR (deI bbR) is treated with these detergents (with or without pH buffers present), even though deionized blue bR containing all the lipids has no photocycle. This suggests that the cation(s) has a role in native bR that is different than in delipidated or monomerized bR, even so far as to suggest that the cation(s) becomes unimportant to the function as the lipids are removed.},
	isbn = {0006-3495},
	doi = {10.1016/S0006-3495(03)74487-7},
	url = {http://dx.doi.org/10.1016/S0006-3495(03)74487-7},
	author = {Heyes, C D and El-Sayed, Mostafa A}
}
@article {1188,
	title = {Thermal properties of bacteriorhodopsin},
	journal = {Journal of Physical Chemistry B},
	volume = {107},
	number = {44},
	year = {2003},
	note = {Heyes, CD El-Sayed, MA},
	month = {Nov},
	pages = {12045-12053},
	abstract = {In this Feature Article we review the effects of various parameters on the structure and thermal stability of one of the most widely studied membrane proteins, bacteriorhodopsin. This protein has recently been crystallized and its high-resolution structure elucidated to 1.55 Angstrom. This information has proved invaluable in understanding its proton-pumping mechanism. However, the question of why bacteriorhodopsin is so stable over a wide range of conditions, and which factors contribute to this stability, is still largely unanswered. Spectroscopic and calorimetric experiments provide information on the thermodynamics, kinetics and structural changes upon unfolding and refolding the protein under various environmental perturbations. FT-IR spectroscopy has been particularly useful in determining the changes in secondary structure upon heating through its thermal transitions after changing pH and cations, removing and adding lipids and detergents, retinal reduction and removal, and site-directed mutagenesis. These experiments are reviewed, and the information that they have afforded have been brought together to try to understand how nature has controlled the conditions of bR to make it one of the most stable proteins known.},
	isbn = {1520-6106},
	doi = {10.1021/jp035327b},
	author = {Heyes, C D and El-Sayed, Mostafa A}
}
@article {1190,
	title = {Characterization of pt nanoparticles encapsulated in Al2O3 and their catalytic efficiency in propene hydrogenation},
	journal = {Journal of Physical Chemistry A},
	volume = {106},
	number = {10},
	year = {2002},
	note = {Yoo, JW Hathcock, D El-Sayed, MA},
	month = {Mar},
	pages = {2049-2054},
	abstract = {Pt nanoparticles supported in nanoporous Al2O3 catalyst are prepared by reduction of K2PtCl4 solution using 112 in the presence of Al2O3 and poly(acrylic acid) as capping; material. After thorough washing with water to remove Pt nanoparticles located on the external surface of the Al2O3 and drying at 70 degreesC for 12 h, they were used in propene hydrogenation to evaluate catalytic activity as measured by the value of the activation energy in the temperature range between 30 and 90 degreesC. The Pt nanoparticles are characterized by using transmission electron microscopy (TEM). The particles in Pt/Al2O3 are found to be encapsulated and uniformly dispersed inside the Al2O3; however, the size and shapes are not clearly seen. After extraction of the Pt nanoparticles from the Al2O3 channels by using an ethanol-diluted HF solution, various shapes such as truncated octahedral, cubic, tetrahedral, and spherical with a size around 5 nm are observed. The encapsulated particles have various shapes but are smaller in size than those prepared in K2PtCl4 solution with polyacrylate in the absence of Al2O3. Using FT-IR studies, the capping material initially used in Pt/Al2O3 is not found in the Al2O3 channels. This might be due to the fact that the polymer (average MW 2100) is too large to be accommodated within the Al2O3 pores. The nanopores of Al2O3 have several roles in the synthesis of these nanoparticles. It allows for uniform dispersion and encapsulation of Pt nanoparticles. It controls the Pt sizes with narrow distribution that is determined by the pore dimension (5.8 nm). It protects against metal particle aggregation and produces various shapes even in the absence of the capping material. Using these Pt nanoparticles, the catalysis of hydrogenation of propene gas was studied. The initial rates, reaction order, rate constants, and activation energy for the hydrogenation are determined by use of mass spectrometric techniques. The activation energy is found to be 5.7 kcal/mol, which is about one-half that previously reported for catalysis by Pt metal deposited in SiO2 and TiO2 synthesized by using H2PtCl6 and Pt(allyl)(2) by impregnation method.},
	isbn = {1089-5639},
	doi = {10.1021/jp0121318},
	author = {Yoo, J. W. and Hathcock, D. J. and El-Sayed, Mostafa A}
}
@article {1191,
	title = {Comparison of the dynamics of the primary events of bacteriorhodopsin in its trimeric and monomeric states},
	journal = {Biophysical Journal},
	volume = {83},
	number = {3},
	year = {2002},
	note = {Wang, JP Link, S Heyes, CD El-Sayed, MA},
	month = {Sep},
	pages = {1557-1566},
	abstract = {In this paper, femtosecond pump-probe spectroscopy in the visible region of the spectrum has been used to examine the ultrafast dynamics of the retinal excited state in both the native trimeric state and the monomeric state of bacteriorhodopsin (bR). It is found that the excited state lifetime (probed at 490 nm) increases only slightly upon the monomerization of bR. No significant kinetic difference is observed in the recovery process of the bR ground state probed at 570 nm nor in the fluorescent state observed at 850 nm. However, an increase in the relative amplitude of the slow component of bR excited state decay is observed in the monomer, which is due to the increase in the concentration of the 13-cis retinal isomer in the ground state of the light-adapted bR monomer. Our data indicate that when the protein packing around the retinal is changed upon bR monomerization, there is only a subtle change in the retinal potential surface, which is dependent on the charge distribution and the dipoles within the retinal-binding cavity. In addition, our results show that 40\% of the excited state bR molecules return to the ground state on three different time scales: one-half-picosecond component during the relaxation of the excited state and the formation of the J intermediate, a 3-ps component as the J changes to the K intermediate where retinal photoisomerization occurs, and a subnanosecond component during the photocycle.},
	isbn = {0006-3495},
	author = {Wang, Jianping and Link, Stephan and Heyes, C D and El-Sayed, Mostafa A}
}
@article {851,
	title = {Fourier transform infrared study of the effect of different cations on bacteriorhodopsin protein thermal stability},
	journal = {Biophysical journal},
	volume = {82},
	year = {2002},
	pages = {1598-1606},
	publisher = {Elsevier},
	abstract = {The effect of divalent ion binding to deionized bacteriorhodopsin (dI-bR) on the thermal transitions of the protein secondary structure have been studied by using temperature-dependent Fourier transform infrared (FT-IR) spectroscopy. The native metal ions in bR, Ca2+, and Mg2+, which we studied previously, are compared with Mn2+, Hg2+, and a large, synthesized divalent organic cation, ((Et)3N)2Bu2+. It was found that in all cases of ion regeneration, there is a pre-melting, reversible conformational transition in which the amide frequency shifts from 1665 to 1652cm-1. This always occurs at \~{}80{\textdegree}C, independent of which cation is used for the regeneration. The irreversible thermal transition (melting), monitored by the appearance of the band at 1623cm-1, is found to occur at a lower temperature than that for the native bR but higher than that for acid blue bR in all cases. However, the temperature for this transition is dependent on the identity of the cation. Furthermore, it is shown that the mechanism of melting of the organic cation regenerated bR is different than for the metal cations, suggesting a difference in the type of binding to the protein (either to different sites or different binding to the same site). These results are used to propose specific direct binding mechanisms of the ions to the protein of deionized bR.},
	isbn = {0006-3495},
	doi = {10.1016/S0006-3495(02)75511-2},
	url = {http://dx.doi.org/10.1016/S0006-3495(02)75511-2},
	author = {Heyes, C D and Wang, Jianping and Sanii, L. S. and El-Sayed, Mostafa A}
}
@article {1195,
	title = {The quenching of CdSe quantum dots photoluminescence by gold nanoparticles in solution},
	journal = {Photochemistry and Photobiology},
	volume = {75},
	number = {6},
	year = {2002},
	note = {Nikoobakht, B Burda, C Braun, M Hun, M El-Sayed, MA},
	month = {Jun},
	pages = {591-597},
	abstract = {The photoluminescence (PL) of CdSe quantum dots (QD) in aqueous media has been studied in the presence of gold nanoparticles (NP) with different shapes. The steady state PL intensity of CdSe QD (1.5-2 nm in size) is quenched in the presence of gold NP. Picosecond bleach recovery and nanosecond time-resolved luminescence measurements show a faster bleach recovery and decrease in the lifetime of the emitting states of CdSe QD in the presence of quenchers. Surfactant-capped gold nanorods (NR) with aspect ratio of 3 and surfactant-capped and citrate-capped nanospheres (NS) of 12 nm diameter were used as quenchers in order to study the effect of shape and surface charge on the quenching rates. The Stern-Volmer kinetics model is used to examine the observed quenching behavior as a function of the quencher concentration. It was found that the quenching rate of NR is more than 1000 times stronger than that of NS with the same capping material. We also found that the quenching rate decreases as the length of the NR decreases, although the overlap between the CdSe emission and the NR absorption increases. This suggests that the quenching is a result of electron transfer rather than long-range (Forster-type) energy transfer processes. The quenching was attributed to the transfer of electron with energies below the Fermi level of gold to the trap holes of CdSe QD. The observed large difference between NR and NS quenching efficiencies was attributed to the presence of the {110} facets only in the NR, which have higher surface energy.},
	isbn = {0031-8655},
	doi = {10.1562/0031-8655(2002)075<0591:tqocqd>2.0.co;2},
	author = {Nikoobakht, Babak and Burda, Clemens and Braun, Markus and Hun, M. and El-Sayed, Mostafa A}
}
@article {1192,
	title = {Refolding of thermally denatured bacteriorhodopsin in purple membrane},
	journal = {Journal of Physical Chemistry B},
	volume = {106},
	number = {3},
	year = {2002},
	note = {Wang, JP Heyes, CD El-Sayed, MA},
	month = {Jan},
	pages = {723-729},
	abstract = {The change in protein conformational structure and retinal chromophore binding state have been examined by using in situ UV-vis, FTIR, and CD spectroscopies during the thermal denaturation and refolding processes in bacteriorhodopsin (bR) of purple membrane (PM), in its native trimeric and in Triton X-100 solubilized monomeric form. For the trimeric bR, it is found that heating bR through its premelting transition (T > 78 degreesC, T-m{\textquoteright}) does not cause any permanent damage in the protein secondary structure, and a reversible refolding occurs when it cools back to room temperature. For the monomeric bR, it is found that it is less thermally stable than the trimer. There is a significant change in its protein secondary structure and a complete dissociation of retinal occurs irreversibly at a temperature as low as 66 degreesC. In addition, it is found that heating the trimeric bR through its main molten state (T > 96 degreesC, T-m) changes the protein secondary structure so that bR does not refold fully into its original secondary structure. Upon cooling back to room temperature, about 90\% of the bound retinal in native bR recovers after being heated through its premelting transition, whereas only about 12\% of bound retinal recovers if bR is heated above its main melting temperature. It is also found that refolded bR molecules with their retinal chromophore rebound have a photocycle and are capable of pumping protons. Our results also suggest that from its molten state, protein secondary structure refolding precedes retinal rebinding to the Schiff base.},
	isbn = {1520-6106},
	doi = {10.1021/jp013131a},
	author = {Wang, Jianping and Heyes, C D and El-Sayed, Mostafa A}
}
@article {1203,
	title = {The role of the native lipids and lattice structure in bacteriorhodopsin protein conformation and stability as studied by temperature-dependent Fourier transform-infrared spectroscopy},
	journal = {Journal of Biological Chemistry},
	volume = {277},
	number = {33},
	year = {2002},
	note = {Heyes, CD El-Sayed, MA},
	month = {Aug},
	pages = {29437-29443},
	abstract = {We report the effect of partial delipidation and monomerization on the protein conformational changes of bacteriorhodopsin (bR) as a function of temperature. Removal of up to 75\% of the lipids is known to have the lattice structure of the purple membrane, albeit as a smaller unit cell, whereas treatment by Triton monomerizes bR into micelles. The effects of these modifications on the protein secondary structure is analyzed by monitoring the protein amide I and amide II bands in the Fourier transform-infrared (FT-IR) spectra. It is found that removal of the first 75\% of the lipids has only a slight effect on the secondary structure at physiological temperature, whereas monomerizing bR into micelles alters the secondary structure considerably. Upon heating, the bR monomer is found to have a very low thermal stability compared with the native bR with its melting point reduced from 97 to 65 degreesC, and the premelting transition in which the protein changes conformation in native bR at 80 degreesC could not be observed. Also, the N-H to N-D exchange of the amide II band is effectively complete at room temperature, suggesting that there are no hydrophobic regions that are protected from the aqueous medium, possibly explaining the low thermal stability of the monomer. On the other hand, 75\% delipidated bR has its melting temperature close to that of the native bR and does have a pre-melting transition, although the pre-melting transition occurs at significantly higher temperature than that of the native bR (91 degreesC compared with 80 degreesC) and is still reversible. Furthermore, we have also observed that the reversibility of this pre-melting transition of both native and partially delipidated bR is time-dependent and becomes irreversible upon holding at 91 degreesC between 10 and 30 min. These results are discussed in terms of the lipid and lattice contribution to the protein thermal stability of native bR.},
	isbn = {0021-9258},
	doi = {10.1074/jbc.M203435200},
	author = {Heyes, C D and El-Sayed, Mostafa A}
}
@article {1204,
	title = {Direct observation of charge-transfer dynamics in a conjugated conducting polymer poly (3-octylthiophene)-fullerene composite by time-resolved infrared spectroscopy},
	journal = {Physical Review B},
	volume = {64},
	number = {23},
	year = {2001},
	note = {Wang, JP Li, Y Hong, XY El-Sayed, MA},
	month = {Dec},
	abstract = {Transient infrared-active vibrational (IRAV) modes observed in the pi -conjugated conducting polymers upon photoexcitation are usually used to characterize the dynamics of the photoinduced charge separation and recombination processes. In this paper, the dynamic behavior of photogenerated charge carrier in the poly(3-octylthiophene) (P3OT) conducting polymer doped with fullerene (C(60)) has been studied by using step-scan time-resolved Fourier-transform infrared spectroscopy at room temperature in the 2500-900-cm(-1) (0.31-0.11-eV) frequency region. Upon photoexcitation with a 10-ns laser pulses, it is observed that IRAV modes appear in the similar vibrational frequency regions for pure P3OT and C(60)-doped P3OT; however, the observed IRAV modes is enhanced by 800\% in intensity in the presence of small amount of C(60) (e.g., 10\%). Our results also show that the charge separation occurs instantaneously within the laser pulse width (10 ns), whereas the charge recombination processes occur in the microseconds to a few milliseconds time domain. In addition, the observed enhancement in the IRAV modes upon C(60) doping indicates an enhanced photogeneration efficiency of the charge separation.},
	isbn = {1098-0121},
	doi = {10.1103/PhysRevB.64.235413},
	author = {Wang, Jianping and Li, Y. and Hong, X. Y. and El-Sayed, Mostafa A}
}
@article {1217,
	title = {Effect of temperature, pH, and metal ion binding on the secondary structure of bacteriorhodopsin: FT-IR study of the melting and premelting transition temperatures},
	journal = {Biochemistry},
	volume = {40},
	number = {39},
	year = {2001},
	note = {Heyes, CD El-Sayed, MA},
	month = {Oct},
	pages = {11819-11827},
	abstract = {We have measured the temperature dependence of the FT-IR spectra of bacteriorhodopsin (bR) as a function of the pH and of the divalent cation regeneration with Ca2+ and Mg2+. It has been found that although the irreversible melting transition shows a strong dependence on the pH of the native bR, the premelting reversible transition at 78-80 degreesC shows very little variation over the pH range studied. It is further shown that the acid blue bR shows a red-shifted amide I spectrum at physiological temperature, which shows a more typical alpha -helical frequency component at 1652 cm(-1) and could be the reason for the observed reduction of its melting temperature and lack of an observed premelting transition. Furthermore, the thermal transitions for Ca2+- and Mg2+-regenerated bR (Ca-bR and Mg-bR, respectively) each show a premelting transition at the same 78-80 degreesC temperature as the native purple membrane, but the irreversible melting transition has a slight dependence on the cation identity. The pH dependence of the Ca2+-regenerated bR is studied, and neither transition varies over the pH range studied. These results are discussed in terms of the cation contribution to the secondary structural stability in bR.},
	isbn = {0006-2960},
	doi = {10.1021/bi002594o},
	author = {Heyes, C D and El-Sayed, Mostafa A}
}
@article {1231,
	title = {Suzuki cross-coupling reactions catalyzed by palladium nanoparticles in aqueous solution},
	journal = {Organic Letters},
	volume = {2},
	number = {15},
	year = {2000},
	note = {Li, Y Hong, XM Collard, DM El-Sayed, MA},
	month = {Jul},
	pages = {2385-2388},
	abstract = {[GRAPHICS] Palladium nanoparticles stabilized by poly(N-vinyl-2-pyrrolidone) (PVP) are efficient catalysts for the Suzuki reactions in aqueous medium. The time dependence of the fluorescence intensity of the biphenyl product in the reaction between iodobenzene and phenylboronic acid is used to determine the initial rate of the catalytic reaction. The initial rate depends linearly on the concentration of Pd catalyst, suggesting that the catalytic reaction occurs on the surface of the Pd nanoparticles.},
	isbn = {1523-7060},
	doi = {10.1021/ol0061687},
	author = {Li, Y. and Hong, X. M. and Collard, D. M. and El-Sayed, Mostafa A}
}
@article {877,
	title = {{\textquotedblleft}Cubic{\textquotedblright} Colloidal Platinum Nanoparticles},
	journal = {Chemistry of Materials},
	volume = {8},
	year = {1996},
	note = {doi: 10.1021/cm9601190},
	month = {1996},
	pages = {1161 - 1163},
	publisher = {American Chemical Society},
	abstract = {Cubic platinum nanoparticles (4-18 nm) have been synthesized for the first time in solution by the controlled reduction of K2PtCl4 with hydrogen gas in the presence of sodium polyacrylate as a capping material. The nanoparticles are found to have fee structures, similar to the bulk metal with {100} facets.},
	isbn = {0897-4756},
	doi = {10.1021/cm9601190},
	url = {http://dx.doi.org/10.1021/cm9601190},
	author = {Ahmadi, Temer S. and Wang, Z.L. and Henglein, A. and El-Sayed, Mostafa A}
}
@article {1264,
	title = {Photodissociation dynamics of iodobenzene by state-selective photofragment translational spectroscopy},
	journal = {Journal of Photochemistry and Photobiology A: Chemistry},
	volume = {102},
	year = {1996},
	pages = {13-20},
	publisher = {Elsevier},
	abstract = {State-selective photofragment translational spectroscopy is used to probe the detailed nature of the photodissociation dynamics of iodobenzene at 304 nm. Simultaneous determination of the recoil speed, the spatial anisotropy, and the final state of the iodine fragment reveals that three dissociation channels with different dynamical characteristics compete in the photodissociation of iodobenzene at 304 nm. Based on the observed energy partitioning between the internal and translational modes and the dissociation time td determined from the spatial anisotropy by using a rotational depolarization model, the three dissociation channels are assigned as follows. Two fast dissociation channels, which result in formation of I *(2P1/2) (td=0.4 ps, quantum yield Φ=0.005{\textpm}0.002) and high velocity I(2P3/2) (td=0.3 ps, Φ=0.70{\textpm}0.04), are due to a parallel transition to the repulsive 3Q0(n,σ*) state in the CI bond, followed by dissociation along the same state or curve crossing to the 1Q1 state respectively. A slow dissociation channel (td=0.5{\textendash}1.4 ps, Φ=0.30{\textpm}0.04) which produces low velocity I(2P3/2) is due to a parallel transition to the triplet π,π* state(s) in the phenyl ring that is predissociated by the repulsive n,σ* state(s). The dissociation times determined in the present work are in excellent agreement with those of the recent femtosecond real-time measurements by Cheng et al. at 278 nm},
	isbn = {1010-6030},
	doi = {10.1016/S1010-6030(96)04369-9},
	author = {Hwang, Hyun Jin and El-Sayed, Mostafa A}
}
@article {862,
	title = {Shape-Controlled Synthesis of Colloidal Platinum Nanoparticles},
	journal = {Science (New York, N.Y.)},
	volume = {272},
	year = {1996},
	month = {1996 Jun 28},
	pages = {1924-6},
	abstract = {The shapes and sizes of platinum nanoparticles were controlled by changes in the ratio of the concentration of the capping polymer material to the concentration of the platinum cations used in the reductive synthesis of colloidal particles in solution at room temperature. Tetrahedral, cubic, irregular-prismatic, icosahedral, and cubo-octahedral particle shapes were observed, whose distribution was dependent on the concentration ratio of the capping polymer material to the platinum cation. Controlling the shape of platinum nanoparticles is potentially important in the field of catalysis.},
	issn = {1095-9203},
	doi = {10.1126/science.272.5270.1924},
	author = {Ahmadi, Temer S. and Wang, Z.L. and Green, T.C. and Henglein, A. and El-Sayed, Mostafa A}
}
@article {1282,
	title = {The Wavelength Dependence of the Rates of Internal Energy Redistribution during the Photodissociation of 3-Iodopyridine},
	journal = {The Journal of Physical Chemistry},
	volume = {99},
	year = {1995},
	note = {doi: 10.1021/j100019a024},
	month = {1995},
	pages = {7395 - 7406},
	publisher = {American Chemical Society},
	abstract = {View http://dx.doi.org/10.1021/j100019a024 for article{\textquoteright}s front page in lieu of an abstract},
	isbn = {0022-3654},
	doi = {doi: 10.1021/j100019a024},
	url = {http://dx.doi.org/10.1021/j100019a024},
	author = {Freitas, John E. and El-Sayed, Mostafa A and Hwang, Hyun Jin}
}
