%0 Journal Article %J Journal of The Electrochemical Society %D 2020 %T Ambient Ammonia Electrosynthesis from Nitrogen and Water by Incorporating Palladium in Bimetallic Gold–Silver Nanocages %A Nazemi, M. %A Soule, L. %A Liu, M. %A El-Sayed, M. A. %B Journal of The Electrochemical Society %G eng %0 Journal Article %J ACS Catalysis %D 2020 %T Electrosynthesis of Ammonia Using Porous Bimetallic Pd–Ag Nanocatalysts in Liquid- and Gas-Phase Systems %A Nazemi, M. %A Ou, P. %A Alabbady, A. %A Soule, L. %A Liu, A. %A Song, J. %A Sulchek, T.A. %A Liu, M. %A El-Sayed, M. A. %K display %B ACS Catalysis %G eng %& 10197 %0 Journal Article %J Talanta %D 2020 %T Plasmonic and chiroplasmonic nanobiosensors based on gold nanoparticles %A Sharifi, M. %A Hosseinali, S.H. %A Alizadeh, R.H. %A Hasan, A. %A Attar, F. %A Salihi, A. %A Shekha, M.S. %A Amen, K.M. %A Aziz, F.M. %A Saboury, A.A. %A Akhtari, K. %A Taghizadeh, A. %A Hooshmand, N. %A El-Sayed, M. A. %A Falahati, M. %B Talanta %G eng %0 Journal Article %J Chemical Science %D 2019 %T Monitoring the dynamics of hemeoxygenase-1 activation in head and neck cancer cells in real-time using plasmonically enhanced Raman spectroscopy %A Panikkanvalappil, S. R. %A Garlapati, C. %A Hooshmand, N. %A Aneja, R. %A El-Sayed, M. A. %B Chemical Science %G eng %0 Journal Article %J Physical Chemistry Chemical Physics %D 2018 %T Defect engineering in 1D Ti–W oxide nanotube arrays and their correlated photoelectrochemical performance %A A.A. Abdelhafiz %A M.A. Ganzoury %A Amer, A. W. %A A.A. Faiad %A A.M. Khalifa %A S.Y. AlQaradawi %A El-Sayed, M. A. %A Alamgir, F. M. %A Allam, N. K. %B Physical Chemistry Chemical Physics %G eng %& 10258 %0 Journal Article %J ACS applied materials & interfaces %D 2018 %T Dual-excitation nanocellulose-plasmonic membranes for molecular and cellular SERS detection %A S. Zhang %A R. Xiong %A Mahmoud, M A %A E. Quigley %A H. Chang %A El-Sayed, M. A. %A Tsukruk, V. V. %B ACS applied materials & interfaces %G eng %0 Journal Article %J The journal of physical chemistry letters %D 2018 %T Electrochemical Synthesis of Ammonia from N2 and H2O under Ambient Conditions Using Pore-Size-Controlled Hollow Gold Nanocatalysts with Tunable Plasmonic Properties %A M. Nazemi %A El-Sayed, M. A. %B The journal of physical chemistry letters %G eng %0 Journal Article %J Nano Energy %D 2018 %T Enhancing the rate of electrochemical nitrogen reduction reaction for ammonia synthesis under ambient conditions using hollow gold nanocages %A M. Nazemi %A Panikkanvalappil, S. R. %A El-Sayed, M. A. %K display %B Nano Energy %G eng %0 Book Section %B Inorganic Frameworks as Smart Nanomedicines %D 2018 %T Gold nanoparticles for cancer diagnostics, spectroscopic imaging, drug delivery, and plasmonic photothermal therapy %A M. Aioub %A L.A. Austin %A El-Sayed, M. A. %B Inorganic Frameworks as Smart Nanomedicines %G eng %& 2 %0 Journal Article %J ACS nano %D 2018 %T Gold Nanorod-Photothermal Therapy Alters Cell Junctions and Actin Network in Inhibiting Cancer Cell Collective Migration %A Y. Wu %A Ali, M. R. K. %A B. Dong %A T. Han %A K. Chen %A J. Chen %A Y. Tang %A N. Fang %A F. Wang %A El-Sayed, M. A. %B ACS nano %G eng %0 Journal Article %J Journal of Materials Chemistry B %D 2018 %T Real-Time Tracking of Autophagy Process in Living Cells Using Plasmonically Enhanced Raman Spectroscopy of Fucoidan-Coated Gold Nanoparticles %A Jang, H %A K. Kang %A El-Sayed, M. A. %B Journal of Materials Chemistry B %G eng %0 Journal Article %J The Journal of Physical Chemistry C %D 2018 %T Single-Crystal Electrospun Plasmonic Perovskite Nanofibers %A A.M. Abdellah %A A. Hafez %A Panikkanvalappil, S. R. %A El-Sayed, M. A. %A Allam, N. K. %B The Journal of Physical Chemistry C %G eng %0 Patent %B US Patent %D 2017 %T Shape tunable plasmonic nanoparticles %A El-Sayed, M. A. %A El-Sayed, I H %B US Patent %V 9,588,124 %G eng %0 Journal Article %J Chemical Science %D 2016 %T Elucidation of Ultraviolet RadiationInduced Cell Responses and Intracellular Biomolecular Dynamics in Mammalian Cells Using Surface-Enhanced Raman Spectroscopy %A Panikkanvalappil, S. R. %A Hira, S. M. %A El-Sayed, M. A. %B Chemical Science %G eng %0 Journal Article %J Am. Chem. Soc. %D 2016 %T Photoexcited Surface Frustrated Lewis Pairs for Heterogeneous Photocatalytic Co2 Reduction %A Ghuman, K. K. %A Hoch, L. B. %A Szymanski, P. %A Loh, J. Y. %A Kherani, N. P. %A El-Sayed, M. A. %A Ozin, G. A. %A Singh, C. V. %B Am. Chem. Soc. %G eng %0 Journal Article %J J. Phys. Chem. %D 2016 %T Tuning the Photoactivity of Zirconia NanotubesBased Photoanodes Via Ultra-Thin Layers of Zrn: An Effective Approach Towards Visible Light-Water Splitting %A Amer, A. W. %A El-Sayed, M. A. %A Allam, N. K. %B J. Phys. Chem. %G eng %0 Journal Article %J Acs Applied Materials & Interfaces %D 2014 %T Energy-Transfer Efficiency in Eu-Doped ZnO Thin Films: The Effects of Oxidative Annealing on the Dynamics and the Intermediate Defect States %A Ahmed, S. M. %A Szymanski, P. %A El-Nadi, L. M. %A El-Sayed, M. A. %B Acs Applied Materials & Interfaces %V 6 %P 1765-1772 %8 Feb %@ 1944-8244 %G eng %M WOS:000331493200059 %R 10.1021/am404662k %0 Journal Article %J Chemistry of Materials %D 2014 %T Hollow and Solid Metallic Nanoparticles in Sensing and in Nanocatalysis %A Mahmoud, M A %A O'Neil, D. %A El-Sayed, M. A. %K n/a %B Chemistry of Materials %V 26 %P 44-58 %8 Jan %@ 0897-4756 %G eng %M WOS:000330416900006 %! Chem Mater %R 10.1021/cm4020892 %0 Journal Article %J Journal of Physical Chemistry B %D 2014 %T The Most Effective Gold Nanorod Size for Plasmonic Photothermal Therapy: Theory and In Vitro Experiments %A Mackey, M. A. %A Ali, M. R. K. %A Austin, Lauren %A Near, R. D. %A El-Sayed, M. A. %B Journal of Physical Chemistry B %V 118 %P 1319-1326 %8 Feb %@ 1520-6106 %G eng %M WOS:000331153800015 %! J. Phys. Chem. B %R 10.1021/jp409298f %0 Journal Article %J Nano Letters %D 2014 %T Shape- and Symmetry-Dependent Mechanical Properties of Metallic Gold and Silver on the Nanoscale %A Mahmoud, M A %A O'Neil, D. %A El-Sayed, M. A. %B Nano Letters %V 14 %P 743-748 %8 Feb %@ 1530-6984 %G eng %M WOS:000331343900053 %! Nano Lett. %R 10.1021/nl4040362 %0 Journal Article %J Bioconjugate Chemistry %D 2014 %T XAV939: From a Small Inhibitor to a Potent Drug Bioconjugate When Delivered by Gold Nanoparticles %A Afifi, M. M. %A Austin, Lauren %A Mackey, M. A. %A El-Sayed, M. A. %B Bioconjugate Chemistry %V 25 %P 207-215 %8 Feb %@ 1043-1802 %G eng %M WOS:000331779700003 %! Bioconjugate Chem %R 10.1021/bc400271x %0 Journal Article %J Applied Physics Letters %D 2013 %T Bandgap bowing in Ta-W-O system for efficient solar energy conversion: Insights from density functional theory and X-ray diffraction %A Nashed, R. %A Alamgir, F. M. %A Jang, S. S. %A Ismail, Y. %A El-Sayed, M. A. %A Allam, N. K. %B Applied Physics Letters %V 103 %8 Sep %@ 0003-6951 %G eng %M WOS:000325284500110 %] 133905 %! Appl. Phys. Lett. %R 10.1063/1.4823543 %0 Journal Article %J Journal of Physical Chemistry C %D 2013 %T Determining the Mechanism of Solution Metallic Nanocatalysis with Solid and Hollow Nanoparticles: Homogeneous or Heterogeneous %A Mahmoud, M A %A Garlyyev, B. %A El-Sayed, M. A. %B Journal of Physical Chemistry C %V 117 %P 21886-21893 %8 Oct %@ 1932-7447 %G eng %M WOS:000326260000031 %! J. Phys. Chem. C %R 10.1021/jp4079234 %0 Journal Article %J Journal of Physical Chemistry Letters %D 2013 %T Different Plasmon Sensing Behavior of Silver and Gold Nanorods %A Mahmoud, M A %A El-Sayed, M. A. %B Journal of Physical Chemistry Letters %V 4 %P 1541-1545 %8 May %@ 1948-7185 %G eng %M WOS:000318536500028 %R 10.1021/jz4005015 %0 Journal Article %J Acs Nano %D 2013 %T Exploiting the Nanoparticle Plasmon Effect: Observing Drug Delivery Dynamics in Single Cells via Raman/Fluorescence Imaging Spectroscopy %A Kang, B. %A Afifi, M. M. %A Austin, Lauren %A El-Sayed, M. A. %B Acs Nano %V 7 %P 7420-7427 %8 Aug %@ 1936-0851 %G eng %M WOS:000323810600108 %! ACS Nano %R 10.1021/nn403351z %0 Journal Article %J Nano Letters %D 2013 %T High-Frequency Mechanical Stirring Initiates Anisotropic Growth of Seeds Requisite for Synthesis of Asymmetric Metallic Nanoparticles like Silver Nanorods %A Mahmoud, M A %A El-Sayed, M. A. %A Gao, J. P. %A Landman, U. %B Nano Letters %V 13 %P 4739-4745 %8 Oct %@ 1530-6984 %G eng %M WOS:000326356300026 %! Nano Lett. %R 10.1021/nl402305n %0 Journal Article %J Journal of Chemical Physics %D 2013 %T Hollow gold nanorectangles: The roles of polarization and substrate %A Near, R. D. %A El-Sayed, M. A. %B Journal of Chemical Physics %V 139 %8 Jul %@ 0021-9606 %G eng %M WOS:000322949300059 %] 044713 %! J. Chem. Phys. %R 10.1063/1.4812931 %0 Journal Article %J Bioconjugate Chemistry %D 2013 %T Inducing Cancer Cell Death by Targeting Its Nucleus: Solid Gold Nanospheres versus Hollow Gold Nanocages %A Mackey, M. A. %A Saira, F. %A Mahmoud, M A %A El-Sayed, M. A. %B Bioconjugate Chemistry %V 24 %P 897-906 %8 Jun %@ 1043-1802 %G eng %M WOS:000320898900008 %! Bioconjugate Chem %R 10.1021/bc300592d %0 Journal Article %J Small %D 2013 %T The Last Step in Converting the Surface Plasmonic Energy into Heat by Nanocages and Nanocubes on Substrates %A Szymanski, P. %A Mahmoud, M A %A El-Sayed, M. A. %B Small %V 9 %P 3934-3938 %8 Dec %@ 1613-6810 %G eng %M WOS:000331282400005 %R 10.1002/smll.201300233 %0 Journal Article %J Journal of Photochemistry and Photobiology a-Chemistry %D 2013 %T Plasmonic enhancement of photodynamic cancer therapy %A Hayden, S. C. %A Austin, Lauren %A Near, R. D. %A Ozturk, R. %A El-Sayed, M. A. %B Journal of Photochemistry and Photobiology a-Chemistry %V 269 %P 34-41 %8 Oct %@ 1010-6030 %G eng %M WOS:000324454900005 %R 10.1016/j.jphotochem.2013.06.004 %0 Journal Article %J Journal of Physical Chemistry C %D 2013 %T Properties of pi-Conjugated Fluorescence Polymer-Plasmonic Nanoparticles Hybrid Materials (vol 116, 13336, 2012) %A Mahmoud, M A %A Poncheri, A. J. %A El-Sayed, M. A. %A Bryant, J. %A Bunz, U. %B Journal of Physical Chemistry C %V 117 %P 4876-4876 %8 Mar %@ 1932-7447 %G eng %M WOS:000315707600060 %! J. Phys. Chem. C %R 10.1021/jp4006197 %0 Journal Article %J Journal of Physical Chemistry C %D 2013 %T Rapid and Efficient Prediction of Optical Extinction Coefficients for Gold Nanospheres and Gold Nanorods %A Near, R. D. %A Hayden, S. C. %A Hunter, R. E. %A Thackston, D. %A El-Sayed, M. A. %B Journal of Physical Chemistry C %V 117 %P 23950-23955 %8 Nov %@ 1932-7447 %G eng %M WOS:000327110500056 %! J. Phys. Chem. C %R 10.1021/jp4082596 %0 Journal Article %J Journal of Physical Chemistry B %D 2013 %T Substrate Effect on the Plasmonic Sensing Ability of Hollow Nanoparticles of Different Shapes %A Mahmoud, M A %A El-Sayed, M. A. %B Journal of Physical Chemistry B %V 117 %P 4468-4477 %8 Apr %@ 1520-6106 %G eng %M WOS:000318211600037 %! J. Phys. Chem. B %R 10.1021/jp3085793 %0 Journal Article %J Acs Nano %D 2013 %T Surface-Enhanced Raman Spectroscopy for Real-Time Monitoring of Reactive Oxygen Species-Induced DNA Damage and Its Prevention by Platinum Nanoparticles %A Panikkanvalappil, S. R. %A Mahmoud, M A %A Mackey, M. A. %A El-Sayed, M. A. %B Acs Nano %V 7 %P 7524-7533 %8 Sep %@ 1936-0851 %G eng %M WOS:000330016900011 %! ACS Nano %R 10.1021/nn403722x %0 Journal Article %J Journal of Physical Chemistry C %D 2013 %T Thermal/Electrochemical Growth and Characterization of One-Dimensional ZnO/TiO2 Hybrid Nanoelectrodes for Solar Fuel Production %A Shaheen, B. S. %A Salem, H. G. %A El-Sayed, M. A. %A Allam, N. K. %B Journal of Physical Chemistry C %V 117 %P 18502-18509 %8 Sep %@ 1932-7447 %G eng %M WOS:000330162700026 %! J. Phys. Chem. C %R 10.1021/jp405515v %0 Journal Article %J Journal of Physical Chemistry C %D 2013 %T Thin to Thick, Short to Long: Spectral Properties of Gold Nanorods by Theoretical Modeling %A Near, R. D. %A Hayden, S. C. %A El-Sayed, M. A. %B Journal of Physical Chemistry C %V 117 %P 18653-18656 %8 Sep %@ 1932-7447 %G eng %M WOS:000330162700044 %! J. Phys. Chem. C %R 10.1021/jp4078344 %0 Journal Article %J Plos One %D 2013 %T Tissue Distribution and Efficacy of Gold Nanorods Coupled with Laser Induced Photoplasmonic Therapy in Ehrlich Carcinoma Solid Tumor Model %A El-Sayed, M. A. %A Shabaka, A. A. %A El-Shabrawy, O. A. %A Yassin, N. A. %A Mahmoud, S. S. %A El-Shenawy, S. M. %A Al-Ashqar, E. %A Eisa, W. H. %A Farag, N. M. %A El-Shaer, M. A. %A Salah, N. %A Al-Abd, A. M. %X Gold nanorods (GNR) within tumor microregions are characterized by their ability to absorb near IR light and emit heat in what is called photoplasmonic effect. Yet, the efficacy of nanoparticles is limited due to intratumoral tissue distribution reasons. In addition, distribution of GNRs to normal tissue might result in non specific toxicity. In the current study, we are assessing the intratumoral and tissue distribution of PEGylated GNRs on the top of its antitumor characteristics when given intravenously or intratumoral to solid tumor bearing mice and coupled with laser photoplasmonic sessions. PEGylated GNRs with a longitudinal size of less than 100 nm were prepared with aspect ratio of 4.6 showing strong surface plasmon absorption at wavelength 800 nm. Pharmacokinetics of GNR after single I.V. administration (0.1 mg/kg) showed very short systemic circulating time (less than 3 h). On the other hand, tissue distribution of I.V. GNR (0.1 mg/kg) to normal animals showed preferential deposition in spleen tissue. Repeated administration of I.V. GNR resulted in preferential accumulation in both liver and spleen tissues. In addition, I.V. administration of GNR to Ehrlich carcinoma tumor bearing mice resulted in similar tissue distribution; tumor accumulation and anti-tumor effect compared to intratumoral administration. In conclusion, the concentration of GNR achieved within tumors microregions after I.V. administration was comparable to I.T. administration and sufficient to elicit tumoral growth arrest when coupled with laser-aided photoplasmonic treatment. %B Plos One %V 8 %8 Oct %@ 1932-6203 %G eng %M WOS:000325434500052 %] e76207 %R 10.1371/journal.pone.0076207 %0 Journal Article %J Journal of the American Chemical Society %D 2012 %T Aggregation and Interaction of Cationic Nanoparticles on Bacterial Surfaces %A Hayden, S. C. %A Zhao, G. X. %A Saha, K. %A Phillips, R. L. %A Li, X. N. %A Miranda, O. R. %A Rotello, V. M. %A El-Sayed, M. A. %A Schmidt-Krey, I. %A Bunz, U. H. F. %X 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. %B Journal of the American Chemical Society %V 134 %P 6920-6923 %8 Apr %@ 0002-7863 %G eng %M WOS:000303139800009 %R 10.1021/ja301167y %0 Journal Article %J Bioconjugate Chemistry %D 2012 %T Antiandrogen Gold Nanoparticles Dual-Target and Overcome Treatment Resistance in Hormone-Insensitive Prostate Cancer Cells %A Dreaden, E. C. %A Gryder, B. E. %A Austin, Lauren %A Defo, B. A. T. %A Hayden, S. C. %A Pi, M. %A Quarles, L. D. %A Oyelere, A. K. %A El-Sayed, M. A. %X 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. %B Bioconjugate Chemistry %V 23 %P 1507-1512 %8 Aug %@ 1043-1802 %G eng %M WOS:000307487300002 %R 10.1021/bc300158k %0 Journal Article %J Accounts of Chemical Research %D 2012 %T Detecting and Destroying Cancer Cells in More than One Way with Noble Metals and Different Confinement Properties on the Nanoscale %A Dreaden, E. C. %A El-Sayed, M. A. %X Today, 1 in 2 males and 1 in 3 females in the United States will develop cancer at some point during their lifetimes, and 1 in 4 males and 1 in 5 females in the United States will die from the disease. New methods for detection and treatment have dramatically improved dancer care in the United States. However, as improved detection and increasing exposure to carcinogens has led to higher rates of cancer incidence, dinidans and researchers have not balanced that increase with a similar decrease in cancer mortality rates. This mismatch highlights a dear and urgent need for increasingly potent and selective methods with which to detect and treat cancers at their earliest stages. Nanotechnology, the use of materials with structural features ranging from 1 to 100 nm in size, has dramatically altered the design, use, and delivery of cancer diagnostic and therapeutic agents. The unique and newly discovered properties of these structures can enhance the specificities with which biomedical agents are delivered, complementing their efficacy or diminishing unintended side effects. Gold (and silver) nanotechnologies afford a particularly unique set of physiological and optical properties which can be leveraged In applications ranging from in vitro/vivo therapeutics and drug delivery to imaging and diagnostics, surgical guidance, and treatment monitoring. Nanoscale diagnostic and therapeutic agents have been in use since the development of micellar nanocarriers and polymer drug nanoconjugates in the mid-1950s, liposomes by Bangham and Watkins in the mid-1960s, and the introduction of polymeric nanoparticles by Langer and Folkman in 1976. Since then, nanoscale constructs such as dendrimers, protein nanoconjugates, and inorganic nanoparticles have been developed for the systemic delivery of agents to specific disease sites. Today, more than 20 FDA-approved diagnostic or therapeutic nanotechnologies are in clinical use with roughly 250 others in clinical development The global market for nano-enabled medical technologies is expected to grow to $70-160 billion by 2015, rivaling the current market share of biologics worldwide. In this Account, we explore the emerging applications of noble metal nanotechnologies in cancer diagnostics and therapeutics carried out by our group and by others. Many of the novel biomedical properties associated with gold and silver nanoparticles arise from confinement effects: (i) the confinement of photons within the particle which can lead to dramatic electromagnetic scattering and absorption (useful in sensing and heating applications, respectively); (ii) the confinement of molecules around the nanoparticle (useful in drug delivery); and (iii) the cellular/subcellular confinement of particles within malignant cells (such as selective, nuclear-targeted cytotoxic DNA damage by gold nanoparticles). We then describe how these confinement effects relate to specific aspects of diagnosis and treatment such as (i) laser photothermal therapy, optical scattering microscopy, and spectroscopic detection, (ii) drug targeting and delivery, and (iii) the ability of these structures to act as intrinsic therapeutic agents which can selectively perturb/inhibit cellular functions such as division. We intend to provide the reader with a unique physical and chemical perspective on both the design and application of these technologies in cancer diagnostics and therapeutics. We also suggest a framework for approaching future research in the field. %B Accounts of Chemical Research %V 45 %P 1854-1865 %8 Dec %@ 0001-4842 %G eng %M WOS:000311858300003 %R 10.1021/ar2003122 %0 Journal Article %J Journal of Physical Chemistry Letters %D 2012 %T Different Methods of Increasing the Mechanical Strength of Gold Nanocages %A Mahmoud, M A %A Szymanski, P. %A El-Sayed, M. A. %X Using the ultrafast coherent modulation of the surface plasmon band intensity with the totally symmetric lattice vibration of gold nanocages, we were able to determine and use their frequencies as a measure of the cage's mechanical stability. The presence of an inner "stiff" transition-metal nanoshell with a higher value of the elastic modulus is found to increase the frequency of the lattice vibration of the outer soft gold nanoshell. This could also explain the observed increase in both the gold lattice vibrational frequency as well as the lattice vibration relaxation time in the Au-Pt and Au-Pd double-shell nanocages. It is also found that when these nanoparticles are assembled into monolayers on quartz substrates by the Langmuir-Blodgett technique, the oscillation frequency of the gold shell with the transition metal having the largest elastic constant suffers the least change in its oscillation frequency as a result of its resistance to distortion as a result of binding to the substrate. %B Journal of Physical Chemistry Letters %V 3 %P 3527-3531 %8 Dec %@ 1948-7185 %G eng %M WOS:000312170600022 %R 10.1021/jz301503z %0 Journal Article %J Journal of the American Chemical Society %D 2012 %T Effect of the Dielectric Constant of the Surrounding Medium and the Substrate on the Surface Plasmon Resonance Spectrum and Sensitivity Factors of Highly Symmetric Systems: Silver Nanocubes %A Mahmoud, M A %A Chamanzar, M. %A Adibi, A. %A El-Sayed, M. A. %X Silver nanocubes (AgNCs), 60 nm, have four extinction surface plasmon resonance (SPR) peaks. The finite difference time domain (FDTD) simulation method is used to assign the absorption and scattering peaks and also to calculate the plasmon field intensity for AgNCs. Because AgNCs have a highly symmetric cubic shape, there is a uniform distribution of the plasmon field around them, and they are thus sensitive to asymmetric dielectric perturbations. When the dielectric medium around a nanoparticle is changed anisotropically, either by placing the particle on a substrate or by coating it asymmetrically with a solvent, the plasmon field is distorted, and the plasmonic absorption and scattering spectra could shift differently. For the 60 nm AgNC, we found that the scattering resonance peak shifted more than the absorption peak. This changes the extinction bandwidth of these overlapping absorption and scattering bands, and consequently the figure of merit of the nanoparticle, as a localized SPR sensor, no longer has a constant value. %B Journal of the American Chemical Society %V 134 %P 6434-6442 %8 Apr %@ 0002-7863 %G eng %M WOS:000302524800053 %R 10.1021/ja300901e %0 Journal Article %J Chemical Society Reviews %D 2012 %T The golden age: gold nanoparticles for biomedicine %A Dreaden, E. C. %A Alkilany, A. M. %A Huang, X. H. %A Murphy, C. J. %A El-Sayed, M. A. %X 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 'gilding the (nanomedicinal) lily', but that a new 'Golden Age' 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). %B Chemical Society Reviews %V 41 %P 2740-2779 %@ 0306-0012 %G eng %M WOS:000301354900016 %R 10.1039/c1cs15237h %0 Journal Article %J Langmuir %D 2012 %T Metallic Double Shell Hollow Nanocages: The Challenges of Their Synthetic Techniques %A Mahmoud, M A %A El-Sayed, M. A. %X Hollow metallic nanoparticles have been attracting the attention of many researchers in the past five years due to their new properties and potential applications. The unique structure of the hollow nanoparticles; presence of two surfaces (internal and external), and the presence of both cavities and pores in the wall surfaces of these nanoparticles are responsible for their unique properties and applications. Here the galvanic replacement technique is used to prepare nanocages made of gold, platinum, and palladium. In addition, hollow double shell nanoparticles are made of two metal shells like Au-Pt, Pt-Au, Au-Pd, Pd-Au, Pd-Pt, and Pt-Pd. Silver nanocubes are used as templates during the synthesis of hollow nanoparticles with single metal shell or double shell nanocages. Most of the problems that could affect the synthesis of solid Silver nanocubes used as template as well as the double shell nanocages and their possible solutions are discussed in a detail. The sizes and shapes of the single-shell and double-shell nanocages were characterized by a regular and high-resolution TEM. A SEM mapping technique is also used to image the surface atoms for the double shell hollow nanoparticles in order to determine the thickness of the two metal shells. In addition, optical studies are used to monitor the effect of the dielectric properties of the other metals on the plasmonic properties of the gold nanoshell in these mixed nanoparticles. %B Langmuir %V 28 %P 4051-4059 %8 Mar %@ 0743-7463 %G eng %M WOS:000301038000004 %R 10.1021/la203982h %0 Journal Article %J Journal of Physical Chemistry C %D 2012 %T Nanocatalysts Can Change the Number of Electrons Involved in Oxidation-Reduction Reaction with the Nanocages Being the Most Efficient %A Weng, G. %A Mahmoud, M A %A El-Sayed, M. A. %X Eosin Y (EY) is a fluorescein derivative dye that can be reduced by accepting either one or two electrons. The one- or two electron reduction potentials have comparable values. The two-electron reduction pathway dominates when sodium borohydride is used, whereas the reduction pathway changes to a one-electron reduction pathway when gold solid (AuNS) or hollow (AuHS) nanosphere catalysts are used. The reduction reaction of EY by borohydride proceeds via one kinetic stage, whereas in the presence of gold nanocatalysts, three different stages are identified. The first stage has the same reaction rate as in the absence of the nanocatalyst, and no one-electron product is observed (absorption peak at 405 nm). The second stage starts when the rate of the disappearance of EY is suddenly increased; a new peak at 405 nm beings to appear. This stage ends when the rate of the disappearance of EY decreases. The third stage has a rate close to that of the first stage, and the EY is reduced again by accepting two electrons. The lifetime of the first stage is greatly affected by the concentration of the nanocatalyst and decreases as the concentration of the nanocatalyst is increased. The conversion ratio of EY to its one electron reduced form is found to increase proportionally with the concentration of the gold nanocatalyst. In the case of using hollow nanospheres as a catalyst, the conversion ratio is found to be 3 times higher than that when using the solid nanospheres due to the cage effect. %B Journal of Physical Chemistry C %V 116 %P 24171-24176 %8 Nov %@ 1932-7447 %G eng %M WOS:000311190800040 %R 10.1021/jp308869m %0 Journal Article %J Time-of-Flight Mass Spectrometry and its Applications %D 2012 %T The one dimensional photofragment translational spectroscopic technique: intramolecular clocking of energy redistribution for molecules falling apart1 %A Hwangl, Hyun Jin %A Grifliths, Jennifer %A El-Sayed, M. A. %B Time-of-Flight Mass Spectrometry and its Applications %P 265 %@ 0444596186 %G eng %0 Journal Article %J Journal of Physical Chemistry C %D 2012 %T Photoelectric Conversion Properties of Dye-Sensitized Solar Cells Using Dye-Dispersing Titania %A Nishikiori, H. %A Uesugi, Y. %A Setiawan, R. A. %A Fujii, T. %A Qian, W. %A El-Sayed, M. A. %X The time-resolved fluorescence and photoelectrochemical properties of dye-sensitized solar cells using crystalline titania electrodes coated with N3 dye-dispersing amorphous titania gel were investigated to clarify the influence of the dye titania interaction and electron transfer on their photoelectric conversion performance. The photocurrent quantum efficiency of the electrodes was remarkably increased by a steam treatment due to the crystallization and densification of the amorphous titania layer compared to that of the untreated electrode. The electron injection from the dye to the crystalline titania foundation via the steam-treated titania dispersing the dye was confirmed to be more efficient than that in the conventional electrodes. The dye-dispersing titania layer prevented interaction between the dye molecules and back electron transfer from the titania to the electrolyte. The charge separation and photoelectric conversion performance of the dye-sensitized solar cells were improved by forming the specific dye-dispersing titania layer. %B Journal of Physical Chemistry C %V 116 %P 4848-4854 %8 Feb %@ 1932-7447 %G eng %M WOS:000301156500062 %R 10.1021/jp2094388 %0 Journal Article %J Journal of Physical Chemistry C %D 2012 %T Properties of pi-Conjugated Fluorescence Polymer-Plasmonic Nanoparticles Hybrid Materials %A Mahmoud, M A %A Poncheri, A. J. %A El-Sayed, M. A. %X Recently, great interest has risen in studying and using hybrid material made by mixing polymeric materials with plasmonic nanoparticles. In the present work, the photophysical properties of two poly(p-phenyleneethynylene) fluorescent polymers, varying in chain length, were studied as a function of (1) pure polymer surface compression after deposition from a Langmuir-Blodgett trough onto a substrate and (2) deposition of a constant amount of polymer onto the surface of silver nanocube arrays of varying particle densities. The results are discussed in terms of the surface pressure and nanoparticle topography effects on conformation of the fluorescent polymer. It was found that the short polymer is much less affected by increased surface pressure, remaining isolated from interchain interaction. The long polymer exhibits signs of conjugation breaking, presumably due to compression of its longer, "tangled", structure. The two polymer chains in the nanoparticle/polymer series of experiments exhibited a blue-shift and a substantial narrowing of their emission spectra when deposited onto the lowest surface pressure nanoparticle sample. With increasing nanoparticle density, the spectra continue to blue-shift and narrow. This effect is presumably a combined effect of conformational changes that shift the emission to higher energy (blue-shift) and plasmonic effects that result in enhancement of primary emission of the polymer (emission from the 0-0 and 1-0 transitions), thus narrowing the emission. %B Journal of Physical Chemistry C %V 116 %P 13336-13342 %8 Jun %@ 1932-7447 %G eng %M WOS:000305444300042 %R 10.1021/jp303908e %0 Journal Article %J Nano Letters %D 2012 %T Real-Time Molecular Imaging throughout the Entire Cell Cycle by Targeted Plasmonic-Enhanced Rayleigh/Raman Spectroscopy %A Kang, B. %A Austin, Lauren %A El-Sayed, M. A. %X Due to their strong enhancement of scattered light, plasmonic nanoparticles have been utilized for various biological and medical applications. Here, we describe a new technique, Targeted Plasmonic-Enhanced Single-Cell Rayleigh/Raman Spectroscopy, to monitor the molecular changes of any cell-component, such as the nucleus, during the different phases of its full cell cycle by simultaneously recording its Rayleigh images and Raman vibration spectra in real-time. The analysis of the observed Raman DNA and protein peaks allowed the different phases of the cell cycle to be identified. This technique could be used for disease diagnostics and potentially improve our understanding of the molecular mechanisms of cellular functions such as division, death, signaling, and drug action. %B Nano Letters %V 12 %P 5369-5375 %8 Oct %@ 1530-6984 %G eng %M WOS:000309615000049 %R 10.1021/nl3027586 %0 Journal Article %J Small %D 2012 %T Small Molecule-Gold Nanorod Conjugates Selectively Target and Induce Macrophage Cytotoxicity towards Breast Cancer Cells %A Dreaden, E. C. %A Mwakwari, S. C. %A Austin, Lauren %A Kieffer, M. J. %A Oyelere, A. K. %A El-Sayed, M. A. %B Small %V 8 %P 2819-2822 %8 Sep %@ 1613-6810 %G eng %M WOS:000308874900006 %R 10.1002/smll.201200333 %0 Journal Article %J Theoretical Chemistry Accounts %D 2012 %T Some recent developments in photoelectrochemical water splitting using nanostructured TiO2: a short review %A Szymanski, P. %A El-Sayed, M. A. %X Photoelectrochemical cells with TiO2 electrodes to convert sunlight and water into gaseous hydrogen and oxygen are a source of clean and renewable fuel. Despite their great potential, far-from-ideal performance and poor utilization of the solar spectrum have prevented them from becoming a widespread and practical technology. We review recent experimental work that uses dynamics measurements to study limitations of photoelectrochemical cells from a fundamental level and the use of TiO2 nanotube arrays as a superior alternative to TiO2 nanoparticles. Through a combination of nanoscale size control, doping, composite materials, and the incorporation of noble-metal nanoparticles, improved performance and light harvesting are demonstrated. %B Theoretical Chemistry Accounts %V 131 %8 Jun %@ 1432-881X %G eng %M WOS:000305517600012 %] 1202 %R 10.1007/s00214-012-1202-2 %0 Journal Article %J Langmuir %D 2012 %T Synthesis and Optical Properties of Small Au Nanorods Using a Seedless Growth Technique %A Ali, M. R. K. %A Snyder, B. %A El-Sayed, M. A. %X Gold nanoparticles have shown potential in photothermal cancer therapy and optoelectronic technology. In both applications, a call for small size nanorods is warranted. In the present work, a one-pot seedless synthetic technique has been developed to prepare relatively small monodisperse gold nanorods with average dimensions (length x width) of 18 x 4.5 nm, 25 x 5 nm, 15 x 4.5 nm, and 10 x 2.5 nm. In this method, the pH was found to play a crucial role in the monodispersity of the nanorods when the NaBH4 concentration of the growth solution was adjusted to control the reduction rate of the gold ions. At the optimized pH and NaBH4 concentrations, smaller gold nanorods were produced by adjusting the CTAB concentration in the growth solution. In addition, the concentration of silver ions in the growth solution was found to be pivotal in controlling the aspect ratio of the nanorods. The extinction coefficient values for the small gold nanorods synthesized with three different aspect ratios were estimated using the absorption spectra, size distributions, and the atomic spectroscopic analysis data. The previously accepted relationships between the extinction coefficient or the longitudinal band wavelength values and the nanorods' aspect ratios found for the large nanorods do not extend to the small size domain reported in the present work. The failure of extending these relationships over larger sizes is a result of the interaction of light with the large rods giving an extinction band which results mostly from scattering processes while the extinction of the small nanorods results from absorption processes. %B Langmuir %V 28 %P 9807-9815 %8 Jun %@ 0743-7463 %G eng %M WOS:000305661400075 %R 10.1021/la301387p %0 Journal Article %J Langmuir %D 2012 %T Synthesis and Optical Properties of Small Au Nanorods Using a Seedless Growth Technique %A Ali, M. R. K. %A Snyder, B. %A El-Sayed, M. A. %X Gold nanoparticles have shown potential in photothermal cancer therapy and optoelectronic technology. In both applications, a call for small size nanorods is warranted. In the present work, a one-pot seedless synthetic technique has been developed to prepare relatively small monodisperse gold nanorods with average dimensions (length x width) of 18 x 4.5 nm, 25 x 5 nm, 15 x 4.5 nm, and 10 x 2.5 nm. In this method, the pH was found to play a crucial role in the monodispersity of the nanorods when the NaBH4 concentration of the growth solution was adjusted to control the reduction rate of the gold ions. At the optimized pH and NaBH4 concentrations, smaller gold nanorods were produced by adjusting the CTAB concentration in the growth solution. In addition, the concentration of silver ions in the growth solution was found to be pivotal in controlling the aspect ratio of the nanorods. The extinction coefficient values for the small gold nanorods synthesized with three different aspect ratios were estimated using the absorption spectra, size distributions, and the atomic spectroscopic analysis data. The previously accepted relationships between the extinction coefficient or the longitudinal band wavelength values and the nanorods' aspect ratios found for the large nanorods do not extend to the small size domain reported in the present work. The failure of extending these relationships over larger sizes is a result of the interaction of light with the large rods giving an extinction band which results mostly from scattering processes while the extinction of the small nanorods results from absorption processes. %B Langmuir %V 28 %P 9807-9815 %8 Jun %@ 0743-7463 %G eng %M WOS:000305661400075 %R 10.1021/la301387p %0 Journal Article %J Journal of Materials Chemistry %D 2012 %T The unusual fluorescence intensity enhancement of poly(p-phenyleneethynylene) polymer separated from the silver nanocube surface by H-bonded LbL shells %A Lisunova, M. %A Mahmoud, M. %A Holland, N. %A Combs, Z. A. %A El-Sayed, M. A. %A Tsukruk, V. V. %X 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. %B Journal of Materials Chemistry %V 22 %P 16745-16753 %@ 0959-9428 %G eng %M WOS:000306972900011 %R 10.1039/c2jm32450d %0 Journal Article %J Journal of the American Chemical Society %D 2011 %T Plasmonic Imaging of Human Oral Cancer Cell Communities during Programmed Cell Death by Nuclear-Targeting Silver Nanoparticles %A Austin, Lauren %A Kang, B. %A Yen, C. W. %A El-Sayed, M. A. %X Plasmonic nanoparticles (NPs) have become a useful platform in Medicine for potential uses in disease diagnosis and treatment. Recently, it has been reported that plasmonic NPs conjugated to nuclear targeting peptides cause DNA damage and apoptotic populations in cancer cells. In the present work, we utilized the plasmonic scattering property and the ability of nuclear-targeted silver nanoparticles (NLS/RGD-AgNPs) to induce programmed cell death in order to image in real-time the behavior of human oral squamous carcinoma (HSC-3) cell communities during and after the induction of apoptosis. Plasmonic live-cell imaging revealed that HSC-3 cells behave as nonprofessional phagocytes. The induction of apoptosis in some cells led to attraction of and their subsequent engulfment by neighboring cells. Attraction to apoptotic cells resulted in clustering of the cellular community. Live-cell imaging also revealed that,. as the initial,concentration of NLS/RGD-AgNPs. increases, the rate of self killing increases and the degree of attraction and clustering decreases. These results are discussed in terms of the proposed mechanism of cells undergoing programmed cell death. %B Journal of the American Chemical Society %V 133 %P 17594-17597 %8 Nov %@ 0002-7863 %G eng %M WOS:000296312200020 %R 10.1021/ja207807t