TY - JOUR T1 - Electrosynthesis of Ammonia Using Porous Bimetallic Pd–Ag Nanocatalysts in Liquid- and Gas-Phase Systems JF - ACS Catalysis Y1 - 2020 A1 - Nazemi, M. A1 - Ou, P. A1 - Alabbady, A. A1 - Soule, L. A1 - Liu, A. A1 - Song, J. A1 - Sulchek, T.A. A1 - Liu, M. A1 - El-Sayed, M. A. KW - display ER - TY - JOUR T1 - Gold nanomaterials as key suppliers in biological and chemical sensing, catalysis, and medicine JF - Biochimica et Biophysica Acta (BBA)-General Subjects Y1 - 2020 A1 - Falahati, M. A1 - Attar, F. A1 - Sharifi, M. A1 - Saboury, A.A. A1 - Salihi, A. A1 - Aziz, F.M. A1 - Kostova, I. A1 - Burda, C. A1 - Priecel, P. A1 - Lopez-Sanchez, J.A. A1 - Laurent, S. A1 - Hooshmand, N. A1 - El-Sayed, M.A. ER - TY - JOUR T1 - Plasmonic and chiroplasmonic nanobiosensors based on gold nanoparticles JF - Talanta Y1 - 2020 A1 - Sharifi, M. A1 - Hosseinali, S.H. A1 - Alizadeh, R.H. A1 - Hasan, A. A1 - Attar, F. A1 - Salihi, A. A1 - Shekha, M.S. A1 - Amen, K.M. A1 - Aziz, F.M. A1 - Saboury, A.A. A1 - Akhtari, K. A1 - Taghizadeh, A. A1 - Hooshmand, N. A1 - El-Sayed, M. A. A1 - Falahati, M. ER - TY - JOUR T1 - Gold Nanoparticle-Assisted Plasmonic Photothermal Therapy Advances towards Clinical Application JF - The Journal of Physical Chemistry C Y1 - 2019 A1 - Ali, M.R. A1 - Wu, Y. A1 - El-Sayed, M.A. ER - TY - JOUR T1 - Gold nanoparticles in biological optical imaging JF - Nano Today Y1 - 2019 A1 - Wu, Y. A1 - Ali, M.R. A1 - Chen, K. A1 - Fang, N. A1 - El-Sayed, M.A. ER - TY - JOUR T1 - Gold Nanorod-Assisted Photothermal Therapy Decreases Bleeding during Breast Cancer Surgery in Dogs and Cats JF - Cancers Y1 - 2019 A1 - Ali, M.R. A1 - Farghali, H.A. A1 - Wu, Y. A1 - El-Sayed, I. A1 - Osman, A.H. A1 - Selim, S.A. A1 - El-Sayed, M.A. ER - TY - JOUR T1 - Improving the Flow Cytometry-based Detection of the Cellular Uptake of Gold Nanoparticles JF - Analytical chemistry Y1 - 2019 A1 - Wu, Y. A1 - Ali, M.R. A1 - Dansby, K. A1 - El-Sayed, M.A. ER - TY - PAT T1 - Methods for inhibiting cancer cell migration with gold nanomaterials and photothermal therapy T2 - U.S. Patent Application 16/029,193 Y1 - 2019 A1 - El-Sayed, M.A. A1 - Ali, M.R. JA - U.S. Patent Application 16/029,193 ER - TY - JOUR T1 - Monitoring the dynamics of hemeoxygenase-1 activation in head and neck cancer cells in real-time using plasmonically enhanced Raman spectroscopy JF - Chemical Science Y1 - 2019 A1 - Panikkanvalappil, S. R. A1 - Garlapati, C. A1 - Hooshmand, N. A1 - Aneja, R. A1 - El-Sayed, M. A. ER - TY - JOUR T1 - Plasmonic gold nanoparticles: Optical manipulation, imaging, drug delivery and therapy JF - Journal of Controlled Release Y1 - 2019 A1 - Sharifi, M. A1 - Attar, F. A1 - Saboury, A.A. A1 - Akhtari, K. A1 - Hooshmand, N. A1 - Hasan, A. A1 - El-Sayed, M.A. A1 - Falahati, M. ER - TY - JOUR T1 - Defect engineering in 1D Ti–W oxide nanotube arrays and their correlated photoelectrochemical performance JF - Physical Chemistry Chemical Physics Y1 - 2018 A1 - A.A. Abdelhafiz A1 - M.A. Ganzoury A1 - Amer, A. W. A1 - A.A. Faiad A1 - A.M. Khalifa A1 - S.Y. AlQaradawi A1 - El-Sayed, M. A. A1 - Alamgir, F. M. A1 - Allam, N. K. ER - TY - CHAP T1 - Gold nanoparticles for cancer diagnostics, spectroscopic imaging, drug delivery, and plasmonic photothermal therapy T2 - Inorganic Frameworks as Smart Nanomedicines Y1 - 2018 A1 - M. Aioub A1 - L.A. Austin A1 - El-Sayed, M. A. JA - Inorganic Frameworks as Smart Nanomedicines ER - TY - JOUR T1 - Gold Nanorod-Photothermal Therapy Alters Cell Junctions and Actin Network in Inhibiting Cancer Cell Collective Migration JF - ACS nano Y1 - 2018 A1 - Y. Wu A1 - Ali, M. R. K. A1 - B. Dong A1 - T. Han A1 - K. Chen A1 - J. Chen A1 - Y. Tang A1 - N. Fang A1 - F. Wang A1 - El-Sayed, M. A. ER - TY - JOUR T1 - Single-Crystal Electrospun Plasmonic Perovskite Nanofibers JF - The Journal of Physical Chemistry C Y1 - 2018 A1 - A.M. Abdellah A1 - A. Hafez A1 - Panikkanvalappil, S. R. A1 - El-Sayed, M. A. A1 - Allam, N. K. ER - TY - JOUR T1 - UV Resonance Raman Study of Apoptosis, Platinum‐based Drugs, and Human Cell Lines JF - ChemPhysChem Y1 - 2018 A1 - Geng, J A1 - M. Aioub A1 - El‐Sayed, M. A. A1 - B.A. Barry ER - TY - JOUR T1 - Efficacy, long-term toxicity, and mechanistic studies of gold nanorods photothermal therapy of cancer in xenograft mice JF - Proceedings of the National Academy of Sciences Y1 - 2017 A1 - Ali, Moustafa RK A1 - et al. KW - display ER - TY - JOUR T1 - Electrochromic tuning of transparent gold nanorods with poly [(3, 4-propylenedioxy) pyrrole] shells in the near-infrared region JF - Journal of Materials Chemistry C Y1 - 2017 A1 - Zhou, J A1 - et al. ER - TY - JOUR T1 - Facile size-controlled synthesis of fucoidan-coated gold nanoparticles and cooperative anticancer effect with doxorubicin JF - Journal of Materials Chemistry B Y1 - 2017 A1 - Jang, H A1 - et al. ER - TY - JOUR T1 - High-sensitivity molecular sensing using plasmonic nanocube chains in classical and quantum coupling regimes JF - Nano Today Y1 - 2017 A1 - Hooshmand, Nasrin A1 - et al. KW - display ER - TY - JOUR T1 - Intracellular assembly of nuclear-targeted gold nanosphere enables selective plasmonic photothermal therapy of cancer by shifting their absorption wavelength toward near-infrared region JF - Bioconjugate Chemistry Y1 - 2017 A1 - Panikkanvalappil, Sajanlal R. A1 - et al. KW - display ER - TY - JOUR T1 - Meniscus-assisted solution printing of large-grained perovskite films for high-efficiency solar cells JF - Nature Communications Y1 - 2017 A1 - He, M A1 - et al. KW - display ER - TY - JOUR T1 - Nuclear Membrane-Targeted Gold Nanoparticles Inhibit Cancer Cell Migration and Invasion JF - ACS Nano Y1 - 2017 A1 - Ali, Moustafa RK A1 - et al. KW - display ER - TY - JOUR T1 - On-Resonance Chiral Metamaterial for Chiroptical Sensing at the Molecular Level JF - CLEO: QELS Fundamental Science Y1 - 2017 A1 - Mousavi, H A1 - et al. ER - TY - JOUR T1 - Platinum-Coated Gold Nanorods: Efficient Reactive Oxygen Scavengers That Prevent Oxidative Damage toward Healthy, Untreated Cells during Plasmonic Photothermal Therapy JF - ACS Nano Y1 - 2017 A1 - Aioub, Mena S A1 - et al. KW - display ER - TY - JOUR T1 - Targeting cancer cell integrins using gold nanorods in photothermal therapy inhibits migration through affecting cytoskeletal proteins JF - Proceedings of the National Academy of Sciences Y1 - 2017 A1 - Ali, Moustafa RK A1 - et al. KW - display ER - TY - JOUR T1 - An Ultraviolet Resonance Raman Spectroscopic Study of Cisplatin and Transplatin Interactions with Genomic DNA JF - Journal of Physical Chemistry B Y1 - 2017 A1 - Geng, J A1 - et al. KW - display ER - TY - JOUR T1 - Unraveling the nature of anomalously fast energy storage in T-Nb2O5 JF - Journal of the American Chemical Society Y1 - 2017 A1 - Chen, D. A1 - et al. ER - TY - JOUR T1 - Advances in Nanomedicine for Head and Neck Cancer JF - Head and Neck Cancer Y1 - 2016 A1 - Panikkanvalappil, S. R. A1 - et al. ER - TY - JOUR T1 - Carrier dynamics and the role of surface defects: Designing a photocatalyst for gas-phase CO2 reduction JF - Proceedings of the National Academy of Sciences Y1 - 2016 A1 - Hoch, L. B. A1 - et al. ER - TY - JOUR T1 - Design of Hybrid Electrochromic Materials with Large Electrical Modulation of Plasmonic Resonances JF - ACS Applied Materials & Interfaces Y1 - 2016 A1 - Ledin, P. A. A1 - et al. ER - TY - JOUR T1 - Dual-Responsive Reversible Plasmonic Behavior of Core–Shell Nanostructures with pH-Sensitive and Electroactive Polymer Shells JF - Chemistry of Materials Y1 - 2016 A1 - Jeon, JW A1 - et al. ER - TY - JOUR T1 - The effect of plasmon resonance coupling in P3HT-coated silver nanodisk monolayers on their optical sensitivity JF - Journal of Materials Chemistry C Y1 - 2016 A1 - Geldmeier, J. A. A1 - et al. ER - TY - JOUR T1 - 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 JF - Journal of Physical Chemistry C Y1 - 2016 A1 - Hooshmand, N. A1 - et al. ER - TY - JOUR T1 - Efficacy and toxicity of plasmonic photothermal therapy (PPTT) using gold nanorods (GNRs) against mammary tumors in dogs and cats JF - Nanomedicine: Nanotechnology, Biology and Medicine Y1 - 2016 A1 - Abdoon, A S A1 - et al. ER - TY - JOUR T1 - Enhanced Electrocatalytic Activity toward the Oxygen Reduction Reaction through Alloy Formation: Platinum–Silver Alloy Nanocages JF - Journal of Physical Chemistry C Y1 - 2016 A1 - Bordley, JA A1 - et al. ER - TY - JOUR T1 - Gold nanorods as drug delivery vehicles for rifampicin greatly improve the efficacy of combating Mycobacterium tuberculosis with good biocompatibility with the host cells JF - Bioconjugate Chemistry Y1 - 2016 A1 - Ali, HR A1 - et al. ER - TY - JOUR T1 - Hyperoxia Induces Intracellular Acidification in Neonatal Mouse Lung Fibroblasts: Real-Time Investigation Using Plasmonically Enhanced Raman Spectroscopy JF - Journal of the American Chemical Society Y1 - 2016 A1 - Panikkanvalappil, Sajanlal R. A1 - James, Masheika A1 - Hira, Steven M A1 - Mobley, James A1 - Jilling, Tamas A1 - Ambalavanan, Namasivayam A1 - El-Sayed, Mostafa A. VL - 138 ER - TY - JOUR T1 - Large Enhancement of Circular Dichroism Using an Embossed Chiral Metamaterial JF - arXiv preprint Y1 - 2016 A1 - Mousavi, S.; A1 - Panikkanvalappil, S. R.; A1 - El-Sayed, M. A.; A1 - Eftekhar, A. A.; A1 - Adibi, A. M3 - 1604.05244 ER - TY - JOUR T1 - Optimizing the antitumor efficacy of AuNR-assisted plasmonic photothermal therapy and its molecular impact JF - Cancer Research Y1 - 2016 A1 - Rahman, MA A1 - et al. ER - TY - JOUR T1 - Photoexcited surface frustrated Lewis pairs for heterogeneous photocatalytic CO2 reduction JF - J. Am. Chem. Soc. Y1 - 2016 A1 - Ghuman, K. K. A1 - et al. ER - TY - JOUR T1 - A Real-Time Surface Enhanced Raman Spectroscopy Study of Plasmonic Photothermal Cell Death Using Targeted Gold Nanoparticles JF - Journal of the American Chemical Society Y1 - 2016 A1 - Aioub, Mena S A1 - El-Sayed, Mostafa A. ER - TY - JOUR T1 - Simultaneous time-dependent surface-enhanced raman spectroscopy, metabolomics, and proteomics reveal cancer cell death mechanisms associated with gold nanorod photothermal therapy JF - Journal of the American Chemical Society Y1 - 2016 A1 - Ali, Moustafa RK A1 - et al. ER - TY - JOUR T1 - Targeting heat shock protein 70 using gold nanorods enhances cancer cell apoptosis in low dose plasmonic photothermal therapy JF - Biomaterials Y1 - 2016 A1 - Ali, Moustafa RK A1 - et al. ER - TY - JOUR T1 - Treatment of natural mammary gland tumors in canines and felines using gold nanorods-assisted plasmonic photothermal therapy to induce tumor apoptosis JF - International journal of nanomedicine Y1 - 2016 A1 - Ali, M. R. K. A1 - et al. ER - TY - JOUR T1 - Tuning the Photoactivity of Zirconia NanotubesBased Photoanodes Via Ultra-Thin Layers of Zrn: An Effective Approach Towards Visible Light-Water Splitting JF - J. Phys. Chem. Y1 - 2016 A1 - Amer, A. W. A1 - El-Sayed, M. A. A1 - Allam, N. K. ER - TY - JOUR T1 - Correction to Shape-and Symmetry-Dependent Mechanical Properties of Metallic Gold and Silver on the Nanoscale JF - Nano letters Y1 - 2015 A1 - Mahmoud, Mahmoud A1 - et al. ER - TY - JOUR T1 - Cytotoxic effects of cytoplasmic-targeted and nuclear-targeted gold and silver nanoparticles in HSC-3 cells–A mechanistic study JF - Toxicology in Vitro Y1 - 2015 A1 - Lauren A. Austin A1 - Ahmad, Samera A1 - Kang, Bin A1 - Rommel, Kathryn R A1 - Mahmoud, Mahmoud A1 - Peek, Mary E A1 - El-Sayed, Mostafa A. VL - 29 ER - TY - JOUR T1 - Probing molecular cell event dynamics at the single-cell level with targeted plasmonic gold nanoparticles: A review JF - Nano Today Y1 - 2015 A1 - Lauren A. Austin A1 - Bing Kang A1 - El-Sayed, Mostafa A. KW - Rayleigh scattering UR - http://www.sciencedirect.com/science/article/pii/S1748013215000973 M3 - http://dx.doi.org/10.1016/j.nantod.2015.07.005 ER - TY - JOUR T1 - Energy-Transfer Efficiency in Eu-Doped ZnO Thin Films: The Effects of Oxidative Annealing on the Dynamics and the Intermediate Defect States JF - Acs Applied Materials & Interfaces Y1 - 2014 A1 - Ahmed, S. M. A1 - Szymanski, P. A1 - El-Nadi, L. M. A1 - El-Sayed, M. A. VL - 6 SN - 1944-8244 N1 - Ahmed, Samah M. Szymanski, Paul El-Nadi, Lotfia M. El-Sayed, Mostafa A. M3 - 10.1021/am404662k ER - TY - JOUR T1 - Enhancing the Efficiency of Gold Nanoparticles Treatment of Cancer by Increasing Their Rate of Endocytosis and Cell Accumulation Using Rifampicin JF - Journal of the American Chemical Society Y1 - 2014 A1 - Ali, Moustafa RK A1 - Panikkanvalappil, Sajanlal R. A1 - El-Sayed, Mostafa A. VL - 136 SN - 0002-7863 J1 - J Am Chem Soc ER - TY - JOUR T1 - The Most Effective Gold Nanorod Size for Plasmonic Photothermal Therapy: Theory and In Vitro Experiments JF - Journal of Physical Chemistry B Y1 - 2014 A1 - Mackey, M. A. A1 - Ali, M. R. K. A1 - Austin, Lauren A1 - Near, R. D. A1 - El-Sayed, M. A. VL - 118 SN - 1520-6106 N1 - Mackey, Megan A. Ali, Moustafa R. K. Austin, Lauren A. Near, Rachel D. El-Sayed, Mostafa A. J1 - J. Phys. Chem. B M3 - 10.1021/jp409298f ER - TY - JOUR T1 - Observing Real-Time Molecular Event Dynamics of Apoptosis in Living Cancer Cells using Nuclear-Targeted Plasmonically Enhanced Raman Nanoprobes JF - ACS nano Y1 - 2014 A1 - Kang, Bin A1 - Austin, Lauren A1 - El-Sayed, Mostafa A. VL - 8 SN - 1936-0851 J1 - ACS Nano ER - TY - JOUR T1 - The optical, photothermal, and facile surface chemical properties of gold and silver nanoparticles in biodiagnostics, therapy, and drug delivery JF - Archives of Toxicology Y1 - 2014 A1 - Austin, Lauren A1 - Mackey, Megan A. A1 - Dreaden, Erik C. A1 - El-Sayed, Mostafa A. SN - 0340-5761 J1 - Arch. Toxicol. ER - TY - JOUR T1 - P‐Glycoprotein‐Dependent Trafficking of Nanoparticle‐Drug Conjugates JF - Small Y1 - 2014 A1 - Dreaden, Erik C. A1 - Raji, Idris O A1 - Austin, Lauren A1 - Fathi, Shaghayegh A1 - Mwakwari, Sandra C A1 - Humphries, William H A1 - Kang, Bin A1 - Oyelere, Adegboyega K A1 - El‐Sayed, Mostafa A VL - 10 SN - 1613-6829 ER - TY - JOUR T1 - Self-Assembled Nanostructured Photoanodes with Staggered Bandgap for Efficient Solar Energy Conversion JF - ACS nano Y1 - 2014 A1 - Nashed, Ramy A1 - Szymanski, Paul A1 - El-Sayed, Mostafa A. A1 - Allam, Nageh K SN - 1936-0851 J1 - ACS Nano ER - TY - JOUR T1 - The Spectroscopy of Homo and Heterodimers of Silver and Gold Nanocubes as a Function of Separation: a DDA Simulation JF - The Journal of Physical Chemistry A Y1 - 2014 A1 - Hooshmand, Nasrin A1 - O'Neil, Daniel A1 - Asiri, Abdullah M A1 - El-Sayed, Mostafa A. SN - 1089-5639 ER - TY - JOUR T1 - XAV939: From a Small Inhibitor to a Potent Drug Bioconjugate When Delivered by Gold Nanoparticles JF - Bioconjugate Chemistry Y1 - 2014 A1 - Afifi, M. M. A1 - Austin, Lauren A1 - Mackey, M. A. A1 - El-Sayed, M. A. VL - 25 SN - 1043-1802 N1 - Afifi, Marwa M. Austin, Lauren A. Mackey, Megan A. El-Sayed, Mostafa A. J1 - Bioconjugate Chem M3 - 10.1021/bc400271x ER - TY - JOUR T1 - Bandgap bowing in Ta-W-O system for efficient solar energy conversion: Insights from density functional theory and X-ray diffraction JF - Applied Physics Letters Y1 - 2013 A1 - Nashed, R. A1 - Alamgir, F. M. A1 - Jang, S. S. A1 - Ismail, Y. A1 - El-Sayed, M. A. A1 - Allam, N. K. VL - 103 SN - 0003-6951 N1 - Nashed, Ramy Alamgir, Faisal M. Jang, Seung Soon Ismail, Yehea El-Sayed, Mostafa A. Allam, Nageh K. J1 - Appl. Phys. Lett. M3 - 10.1063/1.4823543 ER - TY - JOUR T1 - Exploiting the Nanoparticle Plasmon Effect: Observing Drug Delivery Dynamics in Single Cells via Raman/Fluorescence Imaging Spectroscopy JF - Acs Nano Y1 - 2013 A1 - Kang, B. A1 - Afifi, M. M. A1 - Austin, Lauren A1 - El-Sayed, M. A. VL - 7 SN - 1936-0851 N1 - Kang, Bin Afifi, Marwa M. Austin, Lauren A. El-Sayed, Mostafa A. J1 - ACS Nano M3 - 10.1021/nn403351z ER - TY - JOUR T1 - A New Nanotechnology Technique for Determining Drug Efficacy Using Targeted Plasmonically Enhanced Single Cell Imaging Spectroscopy JF - J Am Chem Soc Y1 - 2013 A1 - Austin, Lauren A1 - Kang, Bin A1 - El-Sayed, Mostafa A. AB - Recently, we described a new technique, targeted plasmonically enhanced single cell imaging spectroscopy (T-PESCIS), which exploits the plasmonic properties of gold nanoparticles, e.g. gold nanospheres, to simultaneously obtain enhanced intracellular Raman molecular spectra and enhanced Rayleigh cell scattering images throughout the entire span of a single cell cycle. In the present work, we demonstrate the use of T-PESCIS in evaluating the relative efficacy and dynamics of two popular chemotherapy drugs on human oral squamous carcinoma (HSC-3) cells. T-PESCIS revealed three plasmonically enhanced Raman scattering vibration bands, 500, 1000, and 1585 cm(-1), associated with the cellular death dynamics. Detailed analysis indicated that the decrease in the 500 cm(-1) band did not correlate well with drug efficacy but could indicate death initiation. The time it takes for the relative intensity of either the 1000 or 1585 cm(-1) band ("SERS death" bands) to appear and increase to its maximum value after the injection of a known concentration of the drug can be related to the drug's efficacy. The inverse ratio, termed cell death enhancement factor, of these characteristic death times when using either band, especially the spectrally sharp band at 1000 cm(-1), gave the correct drug efficacy ratio as determined by the commonly used XTT cell viability assay method. These results strongly suggest the potential future use of this technique in determining the efficacy, dynamics, and molecular mechanisms of various drugs against different diseases.[on SciFinder (R)] SN - 1520-5126 N1 - MEDLINE AN 2013441929(Journal; Article; (JOURNAL ARTICLE)) ER - TY - JOUR T1 - Plasmonic enhancement of photodynamic cancer therapy JF - Journal of Photochemistry and Photobiology a-Chemistry Y1 - 2013 A1 - Hayden, S. C. A1 - Austin, Lauren A1 - Near, R. D. A1 - Ozturk, R. A1 - El-Sayed, M. A. VL - 269 SN - 1010-6030 N1 - Hayden, Steven C. Austin, Lauren A. Near, Rachel D. Ozturk, Ramazan El-Sayed, Mostafa A. M3 - 10.1016/j.jphotochem.2013.06.004 ER - TY - JOUR T1 - Thermal/Electrochemical Growth and Characterization of One-Dimensional ZnO/TiO2 Hybrid Nanoelectrodes for Solar Fuel Production JF - Journal of Physical Chemistry C Y1 - 2013 A1 - Shaheen, B. S. A1 - Salem, H. G. A1 - El-Sayed, M. A. A1 - Allam, N. K. VL - 117 SN - 1932-7447 N1 - Shaheen, Basamat S. Salem, Hanadi G. El-Sayed, Mostafa A. Allam, Nageh K. J1 - J. Phys. Chem. C M3 - 10.1021/jp405515v ER - TY - JOUR T1 - Tissue Distribution and Efficacy of Gold Nanorods Coupled with Laser Induced Photoplasmonic Therapy in Ehrlich Carcinoma Solid Tumor Model JF - Plos One Y1 - 2013 A1 - El-Sayed, M. A. A1 - Shabaka, A. A. A1 - El-Shabrawy, O. A. A1 - Yassin, N. A. A1 - Mahmoud, S. S. A1 - El-Shenawy, S. M. A1 - Al-Ashqar, E. A1 - Eisa, W. H. A1 - Farag, N. M. A1 - El-Shaer, M. A. A1 - Salah, N. A1 - Al-Abd, A. M. AB - 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. VL - 8 SN - 1932-6203 N1 - El-Sayed, Mostafa A. Shabaka, Ali A. El-Shabrawy, Osama A. Yassin, Nemat A. Mahmoud, Sawsan S. El-Shenawy, Siham M. Al-Ashqar, Emad Eisa, Wael H. Farag, Niveen M. El-Shaer, Marwa A. Salah, Nabila Al-Abd, Ahmed M. M3 - 10.1371/journal.pone.0076207 ER - TY - Generic T1 - Towards a perfect system for solar hydrogen production: an example of synergy on the atomic scale T2 - SPIE Solar Energy+ Technology Y1 - 2013 A1 - Nashed, Ramy A1 - Alamgir, Faisal M A1 - Seung-Soon, Jang A1 - Ismail, Yehea A1 - El-Sayed, Mostafa A. A1 - Allam, Nageh JA - SPIE Solar Energy+ Technology PB - International Society for Optics and Photonics ER - TY - Generic T1 - Toxicities and antitumor efficacy of tumor-targeted AuNRs in mouse model T2 - CANCER RESEARCH Y1 - 2013 A1 - Peng, Xianghong A1 - Mackey, Megan A1 - Austin, Lauren A1 - Oyelere, Adegboyega A1 - Chen, Georgia A1 - Huang, Xiaohua A1 - El-Sayed, Mostafa A. A1 - Shin, Dong M JA - CANCER RESEARCH PB - AMER ASSOC CANCER RESEARCH 615 CHESTNUT ST, 17TH FLOOR, PHILADELPHIA, PA 19106-4404 USA VL - 73 SN - 0008-5472 J1 - Cancer Res. ER - TY - JOUR T1 - 5-Fluorouracil induces plasmonic coupling in gold nanospheres: new generation of chemotherapeutic agents JF - J. Nanomed. Nanotechnol. Y1 - 2012 A1 - Mohamed, Mona B. A1 - Adbel-Ghani, Nour T. A1 - El-Borady, Ola M. A1 - El-Sayed, Mostafa A. AB - Loading 5- Fluorouracil (5-FU) into gold nanoparticles (AuNPs) could enhance its activity as anticancer drug hugely by enhancing its ability for penetration through the cell membrane. Accordingly, this work is devoted to loading 5-FU into AuNPs surface and studying the binding mechanism of the drug to the surface of the gold nanoparticles. Our finding indicates that new absorption band appears at longer wavelength upon loading 5-FU into gold nanospheres capped with citrate. This near IR band is due to induced surface plasmon coupling via hydrogen bonding between 5-FU and surface capping AuNPs. This leads to great enhancement of the drug action as chemotherapeutic as well as photothermal agents. Factors which affect the binding between 5-FU and the AuNPs such as pH, time after mixing the drug with AuNPs, concn. of the 5-FU, have been studied in detail. Accordingly, the binding interaction is proven to be via hydrogen bonding. Upon the investigation of thermal and photo satiability, the formed composite 5-FU@ AuNPs showed high stability towards these factors. The spectral and morphol. studies were measured via UV-VIS spectroscopy and Transmission Electron Microscopy (HR-TEM). Remarkable increases in the drug anticancer activity upon loading into AuNPs were obsd. for the cell viability test of human colon cancer (HCT16). [on SciFinder(R)] PB - OMICS Publishing Group VL - 3 SN - 2157-7439 N1 - CAPLUS AN 2012:1822923(Journal; Online Computer File) M3 - 10.4172/2157-7439.1000146 ER - TY - JOUR T1 - Antiandrogen Gold Nanoparticles Dual-Target and Overcome Treatment Resistance in Hormone-Insensitive Prostate Cancer Cells JF - Bioconjugate Chemistry Y1 - 2012 A1 - Dreaden, E. C. A1 - Gryder, B. E. A1 - Austin, Lauren A1 - Defo, B. A. T. A1 - Hayden, S. C. A1 - Pi, M. A1 - Quarles, L. D. A1 - Oyelere, A. K. A1 - El-Sayed, M. A. AB - 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. VL - 23 SN - 1043-1802 N1 - 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. M3 - 10.1021/bc300158k ER - TY - JOUR T1 - 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 JF - Journal of the American Chemical Society Y1 - 2012 A1 - Mahmoud, M A A1 - Chamanzar, M. A1 - Adibi, A. A1 - El-Sayed, M. A. AB - 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. VL - 134 SN - 0002-7863 N1 - Times Cited: 3Mahmoud, Mahmoud A. Chamanzar, Maysamreza Adibi, Ali El-Sayed, Mostafa A. M3 - 10.1021/ja300901e ER - TY - JOUR T1 - The golden age: gold nanoparticles for biomedicine JF - Chemical Society Reviews Y1 - 2012 A1 - Dreaden, E. C. A1 - Alkilany, A. M. A1 - Huang, X. H. A1 - Murphy, C. J. A1 - El-Sayed, M. A. AB - 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). VL - 41 SN - 0306-0012 N1 - Times Cited: 54Dreaden, Erik C. Alkilany, Alaaldin M. Huang, Xiaohua Murphy, Catherine J. El-Sayed, Mostafa A. M3 - 10.1039/c1cs15237h ER - TY - JOUR T1 - Real-Time Molecular Imaging throughout the Entire Cell Cycle by Targeted Plasmonic-Enhanced Rayleigh/Raman Spectroscopy JF - Nano Letters Y1 - 2012 A1 - Kang, B. A1 - Austin, Lauren A1 - El-Sayed, M. A. AB - 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. VL - 12 SN - 1530-6984 N1 - Times Cited: 0Kang, Bin Austin, Lauren A. El-Sayed, Mostafa A. M3 - 10.1021/nl3027586 ER - TY - JOUR T1 - Size matters: gold nanoparticles in targeted cancer drug delivery JF - Ther. Delivery Y1 - 2012 A1 - Dreaden, Erik C. A1 - Austin, Lauren A1 - Mackey, Megan A. A1 - El-Sayed, Mostafa A. KW - review gold nanoparticle targeted cancer drug delivery AB - A review. Cancer is the current leading cause of death worldwide, responsible for approx. one quarter of all deaths in the USA and UK. Nanotechnologies provide tremendous opportunities for multimodal, site-specific drug delivery to these disease sites and Au nanoparticles further offer a particularly unique set of phys., chem. and photonic properties with which to do so. This review will highlight some recent advances, by our lab. and others, in the use of Au nanoparticles for systemic drug delivery to these malignancies and will also provide insights into their rational design, synthesis, physiol. properties and clin./preclin. applications, as well as strategies and challenges toward the clin. implementation of these constructs moving forward. [on SciFinder(R)] PB - Future Science Ltd. VL - 3 SN - 2041-5990 N1 - CAPLUS AN 2012:489934(Journal; General Review; Online Computer File) M3 - 10.4155/tde.12.21 ER - TY - JOUR T1 - Small Molecule-Gold Nanorod Conjugates Selectively Target and Induce Macrophage Cytotoxicity towards Breast Cancer Cells JF - Small Y1 - 2012 A1 - Dreaden, E. C. A1 - Mwakwari, S. C. A1 - Austin, Lauren A1 - Kieffer, M. J. A1 - Oyelere, A. K. A1 - El-Sayed, M. A. VL - 8 SN - 1613-6810 N1 - Times Cited: 0Dreaden, Erik C. Mwakwari, Sandra C. Austin, Lauren A. Kieffer, Matthew J. Oyelere, Adegboyega K. El-Sayed, Mostafa A. M3 - 10.1002/smll.201200333 ER - TY - JOUR T1 - Synthesis and Optical Properties of Small Au Nanorods Using a Seedless Growth Technique JF - Langmuir Y1 - 2012 A1 - Ali, M. R. K. A1 - Snyder, B. A1 - El-Sayed, M. A. AB - 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. VL - 28 SN - 0743-7463 M3 - 10.1021/la301387p ER - TY - JOUR T1 - Synthesis and Optical Properties of Small Au Nanorods Using a Seedless Growth Technique JF - Langmuir Y1 - 2012 A1 - Ali, M. R. K. A1 - Snyder, B. A1 - El-Sayed, M. A. AB - 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. VL - 28 SN - 0743-7463 N1 - Times Cited: 2Ali, Moustafa R. K. Snyder, Brian El-Sayed, Mostafa A. M3 - 10.1021/la301387p ER - TY - JOUR T1 - Bacteriorhodopsin/TiO(2) nanotube arrays hybrid system for enhanced photoelectrochemical water splitting JF - Energy & Environmental Science Y1 - 2011 A1 - Allam, N. K. A1 - Yen, C. W. A1 - Near, R. D. A1 - El-Sayed, Mostafa A AB - 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 assembly and use of a bacteriorhodopsin (bR)/TiO(2) nanotube array hybrid electrode system. Photoanode materials composed of similar to 7 mu m long self-ordered and vertically oriented nanotube array of titanium dioxide films were fabricated via the anodization of Ti foil in formamide electrolytes containing NH(4)F at room temperature followed by sensitization of the electrodes with bR. The stability of bR on the TiO(2) surface was found to depend on the pretreatment process of the TiO(2) films. Our results demonstrate the opportunity to fabricate fairly stable bR/TiO(2) hybrid electrodes that can be used as photoanodes for photoelectrochemical water splitting. Under AM 1.5 illumination (100 mW/cm(2)), the hybrid electrodes achieved a photocurrent density of 0.65 mA/cm(2) which is a similar to 50% increase over that measured for pure TiO(2) nanotubes (0.43 mA/cm(2)) fabricated and tested under the same conditions. In the presence of a redox electrolyte, the photocurrent increased to 0.87 mA/cm(2). To the best of our knowledge, this is the first report on the use of bR/TiO(2) hybrid electrodes in photoelectrochemical water oxidation cells. We believe the proton pumping property of bR can be used in a variety of applications, especially those related to third generation photovoltaic cells. VL - 4 SN - 1754-5692 N1 - Allam, Nageh K. Yen, Chun-Wan Near, Rachel D. El-Sayed, Mostafa A. M3 - 10.1039/c1ee01447a ER - TY - JOUR T1 - Electrochemical Fabrication of Strontium-Doped TiO(2) Nanotube Array Electrodes and Investigation of Their Photoelectrochemical Properties JF - Journal of Physical Chemistry C Y1 - 2011 A1 - Hamedani, H. A. A1 - Allam, N. K. A1 - Garmestani, H. A1 - El-Sayed, Mostafa A AB - 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. VL - 115 SN - 1932-7447 N1 - Hamedani, Hoda A. Allam, Nageh K. Garmestani, Hamid El-Sayed, Mostafa A. M3 - 10.1021/jp201194b ER - TY - JOUR T1 - Multimodal plasmon coupling in low symmetry gold nanoparticle pairs detected in surface-enhanced Raman scattering JF - Applied Physics Letters Y1 - 2011 A1 - Dreaden, Erik A1 - Near, R. D. A1 - Abdallah, T. A1 - Talaat, M. H. A1 - El-Sayed, Mostafa A AB - We report on surface-enhanced Raman scattering of silicon phonon vibrations from arrays of gold nanoprism pairs fabricated by electron beam lithography. We found that resonant excitation of the quadrupolar surface plasmon mode of the nanoprisms increases Raman scattering intensity from the substrate as the distance between the nanoparticle pairs decreases. Finite element modeling and plasmon coupling theory indicate that symmetry is reduced as the nanoparticles approach, resulting in increased dipole-quadrupole coupling. Plasmonic enhancement of the incident and Raman-scattered photons results from the dipolar component of the mixed plasmonic field. This effect is expected to be largest in assemblies/aggregates of nanoparticles. (C) 2011 American Institute of Physics. [doi:10.1063/1.3555429] VL - 98 SN - 0003-6951 N1 - Dreaden, Erik C. Near, Rachel D. Abdallah, Tamer Talaat, M. Hassan El-Sayed, Mostafa A. M3 - 10.1063/1.3555429 ER - TY - JOUR T1 - Plasmonic Imaging of Human Oral Cancer Cell Communities during Programmed Cell Death by Nuclear-Targeting Silver Nanoparticles JF - Journal of the American Chemical Society Y1 - 2011 A1 - Austin, Lauren A1 - Kang, B. A1 - Yen, C. W. A1 - El-Sayed, M. A. AB - 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. VL - 133 SN - 0002-7863 N1 - Times Cited: 13Austin, Lauren A. Kang, Bin Yen, Chun-Wan El-Sayed, Mostafa A. M3 - 10.1021/ja207807t ER - TY - JOUR T1 - Remote Triggered Release of Doxorubicin in Tumors by Synergistic Application of Thermosensitive Liposomes and Gold Nanorods JF - Acs Nano Y1 - 2011 A1 - Agarwal, A. A1 - Mackey, M. A. A1 - El-Sayed, Mostafa A A1 - Bellamkonda, R. V. AB - Delivery cif chemotherapeutic agents after encapsulation in nanocarriers such as liposomes diminishes side-effects, as PEGylated nanocarrier pharmacokinetics decrease dosing to healthy tissues and accumulate in tumors due to the enhanced permeability and retention effect. Once in the tumor, however, dosing of the chemotherapeutic to tumor cells is limited potentially by the rate of release from the carriers and the size-constrained, poor diffusivity of nanocarriers in tumor interstitium. Here, we report the design and fabrication of a thermosensitive liposomal nanocarder that maintains its encapsulation stability with a high concentration of doxorubicin payload, thereby minimizing "leak" and attendant toxicity. When used synergistically with PEGylated gold nanorods and near-infrared stimulation, remote triggered release of doxorubicin from thermosensitive liposomes was achieved in a mouse tumor model of human glioblastoma (U87), resulting in a. significant increase in efficacy when compared to nontriggered or nonthermosensitive PEGylated liposomes. This enhancement in efficacy is attributed to increase in tumor-site apoptosis, as was evident from noninvasive apoptosis imaging using Annexin-Vivo 750 probe. This strategy afford; remotely triggered control of tumor dosing of nanocarrier-encapsulated doxorubicin without sacrificing the ability to differentially dose drugs to tumors via the enhanced permeation and retention effect. VL - 5 SN - 1936-0851 N1 - Agarwal, Abhiruchi Mackey, Megan A. El-Sayed, Mostafa A. Bellamkonda, Ravi V. M3 - 10.1021/nn201010q ER - TY - JOUR T1 - Self-Standing Crystalline TiO(2) Nanotubes/CNTs Heterojunction Membrane: Synthesis and Characterization JF - Acs Applied Materials & Interfaces Y1 - 2011 A1 - Hesabi, Z. R. A1 - Allam, N. K. A1 - Dahmen, K. A1 - Garmestani, H. A1 - El-Sayed, Mostafa A AB - 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. VL - 3 SN - 1944-8244 N1 - Hesabi, Zohreh R. Allam, Nageh K. Dahmen, Klaus Garmestani, Hamid El-Sayed, Mostafa A. M3 - 10.1021/am200124p ER - TY - JOUR T1 - Vertically Oriented Ti-Pd Mixed Oxynitride Nanotube Arrays for Enhanced Photoelectrochemical Water Splitting JF - Acs Nano Y1 - 2011 A1 - Allam, N. K. A1 - Poncheri, A. J. A1 - El-Sayed, Mostafa A AB - In recent years, considerable efforts have been made to design and discover photoactive nanostructured materials that can be used as anodes in water photoelectrolysis cells. Herein, we report on the growth of a novel photoanode material composed of self-ordered, vertically oriented nanotube arrays of titanium palladium mixed oxynitride films via anodization of Ti-Pd alloy in an electrolyte solution of formamide containing NH(4)F at room temperature, followed by annealing in an ammonia atmosphere. The nanostructure topology was found to depend on both the anodization time and the applied voltage. Our results demonstrate the ability to grow mixed oxynitride nanotube array films that are several micrometers thick. The Ti-Pd oxynitride nanotube array films were utilized In solar-spectrum water photoelectrolysis, demonstrating a photocurrent density of 1.9 mA/cm(2) and a similar to 5-fold increase in the photoconversion efficiency under AM 1.5 illumination (100 mW/cm(2), 1.0 M KOH) compared to pure TiO(2) nanotubes fabricated and tested under the same conditions; The obtained efficiency is among the highest reported values for a TiO(2) nanotube-based photoelectrochemical cell. This enhancement in the photoconversion efficiency is related to the synergistic effects of Pd alloying, nitrogen doping, and the unique structural properties of the fabricated nanotube arrays. VL - 5 SN - 1936-0851 N1 - Allam, Nageh K. Poncheri, Adam J. El-Sayed, Mostafa A. M3 - 10.1021/nn201136t ER - TY - JOUR T1 - Enhanced Photoassisted Water Electrolysis Using Vertically Oriented Anodically Fabricated Ti-Nb-Zr-O Mixed Oxide Nanotube Arrays JF - Acs Nano Y1 - 2010 A1 - Allam, N. K. A1 - Alamgir, F. A1 - El-Sayed, Mostafa A AB - Self-ordered, highly oriented arrays of titanium-niobium-zirconium mixed oxide nanotube films were fabricated by the anodization of Ti(35)Nb(5)Zr alloy in aqueous and formamide electrolytes containing NH(4)F at room temperature. The nanostructure topology was found to depend on the nature of the electrolyte and the applied voltage. Our results demonstrate the possibility to grow mixed oxide nanotube array films possessing several-micrometer-thick layers by a simple and straightforward electrochemical route. The fabricated Ti-Nb-Zr-O nanotubes showed a similar to 17.5% increase in the photoelectrochemical water oxidation efficiency as compared to that measured for pure TiO(2) nanotubes under UV illumination (100 mW/cm(2), 320-400 nm, 1 M KOH). This enhancement could be related to a combination of the effect of the thin wall of the fabricated Ti-Nb-Zr-O nanotubes (10 +/- 2 nm) and the formation of Zr oxide and Nb oxide layers on the nanotube surface, which seems to slow down the electron-hole recombination in a way similar to that reported for Gratzel solar cells. VL - 4 SN - 1936-0851 N1 - Allam, Nageh K. Alamgir, Faisal El-Sayed, Mostafa A. M3 - 10.1021/nn101678n ER - TY - JOUR T1 - Photoelectrochemical Water Oxidation Characteristics of Anodically Fabricated TiO(2) Nanotube Arrays: Structural and Optical Properties JF - Journal of Physical Chemistry C Y1 - 2010 A1 - Allam, N. K. A1 - El-Sayed, Mostafa A AB - There are currently immense needs to optimize low-cost materials, such as TiO(2), so they can efficiently split water photoelectrochemically into hydrogen and oxygen, thus providing a clean energy fuel. To this end, the nature of the crystalline phase and the dimension of the photocatalyst are of crucial significance. In this study, films of 7 mu m long titania nanotube arrays were fabricated via anodization of titanium foil in formamide electrolytes containing NH(4)F and H(3)PO(4). Upon annealing the as-anodized nanotubes, the anatase-to-rutile phase transformation was found to start at 550 degrees C, which is about 120 degrees C above the temperature observed for the 500 nm long nanotube films, with the nanotube films remaining stable up to 580 degrees C. Analysis of the variation of crystallite size with annealing temperature along with XPS analysis of the films was used to investigate the reason behind this observation. UV-vis measurements showed that the absorption edges of the annealed samples were red shifted from that of the as-anodized sample. The stabilization of the anatase phase up to 550 degrees C, while keeping the tubular structure in place, is very significant as anatase is the most photoactive polymorph of titania. Besides, the 7 mu m long nanotubular structure provides a large surface medium for light utilization through scattering. Used as photoanodes to photoelectrochemically split water, the 580 degrees C crystallized nanotube arrays showed a three-electrode photoconversion efficiency of 10% under UV illumination (100 mW/cm(2), 320-400 nm, 1 M KOH). VL - 114 SN - 1932-7447 N1 - Allam, Nageh K. El-Sayed, Mostafa A. M3 - 10.1021/jp1037014 ER - TY - JOUR T1 - TiO(2) Nanotube/CdS Hybrid Electrodes: Extraordinary Enhancement in the Inactivation of Escherichia coli JF - Journal of the American Chemical Society Y1 - 2010 A1 - Hayden, S. C. A1 - Allam, N. K. A1 - El-Sayed, Mostafa A AB - 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. VL - 132 SN - 0002-7863 N1 - Hayden, Steven C. Allam, Nageh K. El-Sayed, Mostafa A. M3 - 10.1021/ja107034z ER - TY - JOUR T1 - The sensitivity of the energy band gap to changes in the dimensions of the CdSe quantum rods at room temperature: STM and theoretical studies JF - Chemical Physics Letters Y1 - 2009 A1 - Talaat, M. H. A1 - Abdallah, T. A1 - Mohamed, MB A1 - Negm, S. A1 - El-Sayed, Mostafa A AB - The energy band gap of a series of different sizes of CdSe quantum rods have been determined by STM technique at room temperature. The results confirm that the band gap of CdSe quantum rods (QRs) depends mainly on the width (the dimension of the electron confinement) and only slightly on the length as shown previously in the literatures. The experimental data is compared to that calculated using two theoretical models, the effective mass approximation (EMA) and the semi-empirical pseudopotential method (SEPM). The theoretical values for the energy band gap at varying radius are in agreement with the experimental results within 0.08 eV. (c) 2008 Published by Elsevier B.V. VL - 473 SN - 0009-2614 N1 - Talaat, H. Abdallah, T. Mohamed, M. B. Negm, S. El-Sayed, Mostafa A. M3 - 10.1016/j.cplett.2008.11.025 ER - TY - JOUR T1 - Hot electron relaxation dynamics of gold nanoparticles embedded in MgSO4 powder compared to solution: The effect of the surrounding medium JF - Journal of Physical Chemistry B Y1 - 2002 A1 - Link, Stephan A1 - Furube, A. A1 - Mohamed, MB A1 - Asahi, T. A1 - Masuhara, H. A1 - El-Sayed, Mostafa A AB - To test the influence of the surrounding medium on the relaxation dynamics of the plasmon band bleach recovery of gold nanoparticles after excitation with femtosecond laser pulses, we embedded 14.5 and 12.1 nm colloidal gold nanoparticles (synthesized electrochemically) in MgSO4 powder and investigated these samples by femtosecond diffuse reflectance spectroscopy. By measuring the relaxation dynamics over a wide range of excitation energies, we found that the fast decay component is slower by about a factor of 2 for the particles in the MgSO4 powder compared to those in solution while no significant change in the slow decay component is observed. In agreement with this observation, we found that adding solvent to the particles embedded in the powder caused a decrease in the relaxation time from about 10 ps to 5 ps for the fast decay component. This leads to the conclusion that the electron-phonon relaxation in these gold nanoparticles depends on the chemical nature and/or physical phase (solid vs solution) of the surrounding medium. A discussion of this in terms of the type of phonon involved, and the nature of the electron-phonon and phonon-phonon relaxation processes is discussed. To our knowledge, this also presents the first time that a transient bleach could be observed by diffuse reflectance spectroscopy. VL - 106 SN - 1520-6106 N1 - Link, S Furube, A Mohamed, MB Asahi, T Masuhara, H El-Sayed, MA M3 - 10.1021/jp013311k ER - TY - JOUR T1 - Hot electron and phonon dynamics of gold nanoparticles embedded in a gel matrix JF - Chemical Physics Letters Y1 - 2001 A1 - Mohamed, MB A1 - Ahmadi, Temer S. A1 - Link, Stephan A1 - Braun, Markus A1 - El-Sayed, Mostafa A AB - Using pump-probe technique, the dynamics of the hot carriers in metallic nanodots induced by femtosecond laser pulses are investigated in gold nanoparticles embedded in hydrogel and in organic gel and compared to that in aqueous solution. We found that changing the surrounding matrix from aqueous solution to hydrogel and then to organic gel leads to a large increase in the relaxation time of both the electron-phonon (e-ph) and the phonon-phonon (ph-ph) coupling. Furthermore, the ph-ph relaxation time becomes sensitive to the type of the organic solvent trapped in the gel network. This indicates that the relaxation dynamics depend on the thermal conductivity, chemical structure and the molecular dynamics of the surrounding medium. (C) 2001 Elsevier Science BN. All rights reserved. VL - 343 SN - 0009-2614 N1 - Mohamed, MB Ahmadi, TS Link, S Braun, M El-Sayed, MA M3 - 10.1016/s0009-2614(01)00653-4 ER - TY - JOUR T1 - Femtosecond dynamics of a simple merocyanine dye: Does deprotonation compete with isomerization? JF - Journal of the American Chemical Society Y1 - 2000 A1 - Burda, Clemens A1 - Abdel-Kader, M. H. A1 - Link, Stephan A1 - El-Sayed, Mostafa A AB - The primary photochemistry of the trans isomer of a simple merocyanine dye of the stilbazolium betaine type 1-methyl-4-(4'-hydroxytyryl)pyridinium betaine (M-trans) and its conjugate acid MHtrans+ in aqueous solution is studied by femtosecond time-resolved pump probe spectroscopy. The measured rate of the primary photodynamics is determined to be k = 1.1 x 10(12) s(-1) for M-trans at pH 10 and 0.8 x 10(12) s(-1) for MHtrans+ at pH 6. This was assigned to either conformational changes or a simple vibrational relaxation before the actual isomerization takes place. Wavelength excitation studies give support for the former assignment. These results an discussed in terms of the recent results found for the primary processes of retinal in bacteriorhodopsin. Time-resolved transient measurements show that no excited-state deprotonation of MHtrans+ occurs in aqueous solutions at pH 6 or pH 0, suggesting that the deprotonation occurs on a longer time scale than the picosecond time domain. This is in agreement with present theories of intermolecular proton-transfer reactions, which require solvent reorganization as well as the time of deprotonation estimated from the pK(a) value of this molecule in the excited state. The results of our MO calculations on the electronic structure of these two compounds could account for the fact that, while MHtrans+ photoisomerizes, its deprotonated form does not. VL - 122 SN - 0002-7863 N1 - Burda, C Abdel-Kader, MH Link, S El-Sayed, MA M3 - 10.1021/ja993940w ER - TY - JOUR T1 - Effect of Lattice Energy Mismatch on the Relative Mass Peak Intensities of Mixed Alkali Halide Nanocrystals JF - The Journal of Physical Chemistry A Y1 - 1997 A1 - Ahmadi, Temer S. A1 - El-Sayed, Mostafa A AB - The relative mass peak intensity distribution of the [M14-nAnI13]+ mixed alkali halide nanocrystals containing a ?magic? number of 14 metal cations (M and A) and 13 iodide anions is examined. These nanocrystals were generated through sputtering of mixed solid alkali halides using fast atom bombardment and analyzed by use of a double-focusing sector field mass spectrometer. The mass peak intensities of mixed cluster ions composed of two different metals relative to the ?pure? nanocrystals (containing one or the other metal) are compared for two types of mixed cluster ions:? one with small lattice energy mismatch, i.e., [Rb14-nKnI13]+ cluster ions, and the other type with large lattice energy mismatch, i.e., [Cs14-nAnI13]+ cluster ions where A is either Na, K, or Rb. In contrast to what was previously1 found for clusters with small energy mismatch in which the rate of formation (which depends on the possible number of isomers that each mixed cluster ion can have) determines the relative intensities of mass peaks, the rate of evaporation (i.e., the cluster instability) determines the relative mass peak intensities in salts with relatively large lattice energy mismatch. These results are consistent with our previously proposed kinetic model for the formation and decay of these clusters.The relative mass peak intensity distribution of the [M14-nAnI13]+ mixed alkali halide nanocrystals containing a ?magic? number of 14 metal cations (M and A) and 13 iodide anions is examined. These nanocrystals were generated through sputtering of mixed solid alkali halides using fast atom bombardment and analyzed by use of a double-focusing sector field mass spectrometer. The mass peak intensities of mixed cluster ions composed of two different metals relative to the ?pure? nanocrystals (containing one or the other metal) are compared for two types of mixed cluster ions:? one with small lattice energy mismatch, i.e., [Rb14-nKnI13]+ cluster ions, and the other type with large lattice energy mismatch, i.e., [Cs14-nAnI13]+ cluster ions where A is either Na, K, or Rb. In contrast to what was previously1 found for clusters with small energy mismatch in which the rate of formation (which depends on the possible number of isomers that each mixed cluster ion can have) determines the relative intensities of mass peaks, the rate of evaporation (i.e., the cluster instability) determines the relative mass peak intensities in salts with relatively large lattice energy mismatch. These results are consistent with our previously proposed kinetic model for the formation and decay of these clusters. PB - American Chemical Society VL - 101 SN - 1089-5639 UR - http://dx.doi.org/10.1021/jp962045l CP - 4 N1 - doi: 10.1021/jp962045l J1 - J. Phys. Chem. A M3 - doi: 10.1021/jp962045l ER - TY - JOUR T1 - Electron Dynamics of Passivated Gold Nanocrystals Probed by Subpicosecond Transient Absorption Spectroscopy JF - The Journal of Physical Chemistry B Y1 - 1997 A1 - Logunov, Stephan L. A1 - Ahmadi, Temer S. A1 - El-Sayed, Mostafa A A1 - Khoury, J. T. A1 - Whetten, R. L. AB - The electronic dynamics of gold nanocrystals, passivated by a monolayer of alkylthiol(ate) groups, were studied by transient spectroscopy after excitation with subpicosecond laser pulses. Three solution-phase gold samples with average particle size of 1.9, 2.6, and 3.2 nm with size distribution less than 10% were used. The photoexcitation in the intraband (surface plasmon region) leads to the heating of the conduction electron gas and its subsequent thermalization through electron?electron and electron?phonon interaction. The results are analyzed in terms of the contribution of the equilibrated ?hot? electrons to the surface plasmon resonance of gold. A different spectral response was observed for different sizes of gold nanoparticles. The results were compared to the dynamics of the large (30 nm diameter) gold nanocrystals colloidal solution. The size-dependent spectral changes are attributed to the reduction of the density of states for small nanoparticles. The observed variation in the kinetics of the cooling process in gold nanoparticles with changing the laser intensity is attributed to the temperature dependence of the heat capacity of the electron gas.The electronic dynamics of gold nanocrystals, passivated by a monolayer of alkylthiol(ate) groups, were studied by transient spectroscopy after excitation with subpicosecond laser pulses. Three solution-phase gold samples with average particle size of 1.9, 2.6, and 3.2 nm with size distribution less than 10% were used. The photoexcitation in the intraband (surface plasmon region) leads to the heating of the conduction electron gas and its subsequent thermalization through electron?electron and electron?phonon interaction. The results are analyzed in terms of the contribution of the equilibrated ?hot? electrons to the surface plasmon resonance of gold. A different spectral response was observed for different sizes of gold nanoparticles. The results were compared to the dynamics of the large (30 nm diameter) gold nanocrystals colloidal solution. The size-dependent spectral changes are attributed to the reduction of the density of states for small nanoparticles. The observed variation in the kinetics of the cooling process in gold nanoparticles with changing the laser intensity is attributed to the temperature dependence of the heat capacity of the electron gas. PB - American Chemical Society VL - 101 SN - 1520-6106 UR - http://dx.doi.org/10.1021/jp962923f CP - 19 N1 - doi: 10.1021/jp962923f J1 - J. Phys. Chem. B ER - TY - JOUR T1 - Photofragment translational spectroscopy of CH2I2 at 304 nm: Polarization dependence and energy partitioning JF - Bulletin of the Korean Chemical Society Y1 - 1997 A1 - Jung, Kwang-Woo A1 - Ahmadi, Temer S. A1 - El-Sayed, Mostafa A AB - The photodissociation dynamics of CH2I2 has been studied at 304 nm by state-selective photofragment translational spectroscopy. Velocity distributions, anisotropy parameters, and relative quantum yields are obtained for the ground I(P-2(3/2)) and spin-orbit excited state I*(P-2(1/2)) iodine atoms, which are produced from photodissociation of CH2I2 at this wavelength. These processes are found to occur via B-1 <-- A(1) type electronic transitions. The quantum yield of I*(P-2(1/2)) is determined to be 0.25, indicating that the formation of ground state iodine is clearly the favored dissociation channel in the 304 nm wavelength region. From the angular distribution of dissociation products, the anisotropy parameters are determined to be beta(I)=0.4 for the I(P-2(3/2)) and beta (I*)=0.55 for the I*(P-2(1/2)) which substantially differ from the limiting value of 1.13. The positive values of anisotropy parameter, however, show that the primary processes for I and I* formation channels proceed dominantly via a transition which is parallel to I-I axis. The above results are interpreted in terms of dual path formation of iodine atoms from two different excited states, i.e., a direct and an indirect dissociation via curve crossing between these states. The translational energy distributions of recoil fragments reveal that a large fraction of the available energy goes into the internal excitation of the CH2I photofragment; /E-avl=0.80 and 0.82 for the I and I* formation channels, respectively. The quantitative analysis for the energy partitioning of available energy into the photofragments is used to compare the experimental results with the prediction of direct impulsive model for photodissociation dynamics. VL - 18 SN - 0253-2964 N1 - Jung, KW Ahmadi, TS El-Sayed, MA ER - TY - JOUR T1 - Photofragment Translational Spectroscopy of ICl at 304 nm JF - The Journal of Physical Chemistry A Y1 - 1997 A1 - Jung, Kwang-Woo A1 - Ahmadi, Temer S. A1 - El-Sayed, Mostafa A AB - The photodissociation dynamics of ICl is studied at 304 nm by state-selective photofragment translational spectroscopy. Velocity distributions, anisotropy parameters, and relative quantum yields are obtained for the ground I(2P3/2) and spin?orbit excited state I*(2P1/2) iodine atoms, which are produced from photodissociation of ICl at this wavelength. Two sharp velocity distributions are observed for the I channel, suggesting the existence of two dissociation pathways that correlate with ground state iodine formation. Based on the expected translational energy release and the energy separation between those peaks, the two distributions are assigned to dissociation of ICl to I(2P3/2) + Cl(2P3/2) and to I(2P3/2) + Cl*(2P1/2); the former channel appears at higher translational energy. The distribution of I* also shows two strong peaks, indicating that there are two dominant channels for the formation of I* atoms at this wavelength which we assign to the dissociation of ICl forming I*(2P1/2) + Cl(2P3/2) and I*(2P1/2) + Cl*(2P1/2), respectively. The quantum yield of I*(2P1/2) is determined to be 0.30, indicating that the formation of ground state iodine is clearly the favored dissociation channel at 304 nm. The observed anisotropy in the angular distribution of dissociation products (?) indicates that the I* + Cl and I* + Cl* channels are formed predominantly from the parallel transition (? = 1.7 for both channels) while the I + Cl and I + Cl* products are formed mainly from perpendicular transitions (? = ?0.5). The decrease in the anisotropy parameter of the I formation channels from their limiting value of ?1 is attributed to the presence of more than one path for the formation of I + Cl/Cl* photoproducts with opposite polarization for their absorbing transitions. The possible excited state dynamics, which give the observed results, are discussed in terms of the previously proposed energy correlation diagram for ICl.The photodissociation dynamics of ICl is studied at 304 nm by state-selective photofragment translational spectroscopy. Velocity distributions, anisotropy parameters, and relative quantum yields are obtained for the ground I(2P3/2) and spin?orbit excited state I*(2P1/2) iodine atoms, which are produced from photodissociation of ICl at this wavelength. Two sharp velocity distributions are observed for the I channel, suggesting the existence of two dissociation pathways that correlate with ground state iodine formation. Based on the expected translational energy release and the energy separation between those peaks, the two distributions are assigned to dissociation of ICl to I(2P3/2) + Cl(2P3/2) and to I(2P3/2) + Cl*(2P1/2); the former channel appears at higher translational energy. The distribution of I* also shows two strong peaks, indicating that there are two dominant channels for the formation of I* atoms at this wavelength which we assign to the dissociation of ICl forming I*(2P1/2) + Cl(2P3/2) and I*(2P1/2) + Cl*(2P1/2), respectively. The quantum yield of I*(2P1/2) is determined to be 0.30, indicating that the formation of ground state iodine is clearly the favored dissociation channel at 304 nm. The observed anisotropy in the angular distribution of dissociation products (?) indicates that the I* + Cl and I* + Cl* channels are formed predominantly from the parallel transition (? = 1.7 for both channels) while the I + Cl and I + Cl* products are formed mainly from perpendicular transitions (? = ?0.5). The decrease in the anisotropy parameter of the I formation channels from their limiting value of ?1 is attributed to the presence of more than one path for the formation of I + Cl/Cl* photoproducts with opposite polarization for their absorbing transitions. The possible excited state dynamics, which give the observed results, are discussed in terms of the previously proposed energy correlation diagram for ICl. PB - American Chemical Society VL - 101 SN - 1089-5639 UR - http://dx.doi.org/10.1021/jp970837p CP - 36 N1 - doi: 10.1021/jp970837p J1 - J. Phys. Chem. A M3 - doi: 10.1021/jp970837p ER - TY - JOUR T1 - Steps, ledges and kinks on the surfaces of platinum nanoparticles of different shapes JF - Surface science Y1 - 1997 A1 - Wang, Z.L. A1 - Ahmad, TS A1 - El-Sayed, Mostafa A AB - Platinum nanoparticles with a high percentage of cubic-, tetrahedral- and octahedral-like shapes, respectively, have been synthesized by a shape-controlling technique that we developed recently [Ahmadi et al., Science 272 (June 1996) 1924]. High resolution transmission electron microscopy (HRTEM) is used here to directly image the atomic scale structures of the surfaces of these particles with different shapes. The truncated shapes of these particles are mainly defined by the {100}, {111}, and {110} facets, on which numerous atom-high surface steps, ledges and kinds have been observed. This atomic-scale fine structure of the surfaces of these particles is expected to play a critical role in their catalytic activity and selectivity. PB - Elsevier VL - 380 SN - 0039-6028 CP - 2-3 M3 - 10.1016/S0039-6028(97)05180-7 ER - TY - JOUR T1 - “Cubic” Colloidal Platinum Nanoparticles JF - Chemistry of Materials Y1 - 1996 A1 - Ahmadi, Temer S. A1 - Wang, Z.L. A1 - Henglein, A. A1 - El-Sayed, Mostafa A AB - 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. PB - American Chemical Society VL - 8 SN - 0897-4756 UR - http://dx.doi.org/10.1021/cm9601190 CP - 6 N1 - doi: 10.1021/cm9601190 J1 - Chem. Mater. M3 - 10.1021/cm9601190 ER - TY - JOUR T1 - Picosecond Dynamics of Colloidal Gold Nanoparticles JF - The Journal of Physical Chemistry Y1 - 1996 A1 - Ahmadi, Temer S. A1 - Logunov, Stephan L. A1 - El-Sayed, Mostafa A AB - Colloidal gold nanoparticles with an average radius of 15 nm have a surface plasmon absorption band at 530 nm. Excitation by laser pulses of 450 fs duration, and wavelength of 600 or 380 nm ?bleached? the plasmon band and produced a transient absorption at the wings of the ?bleach? spectrum. The transient absorption was found to have a similar temporal behavior at different wavelengths. Analysis of their temporal behavior showed two time constants:? 2.5 ps, and a slower component of >50 ps. Laser excitation close to the plasmon band at 600 nm leads to the formation of ?hot? non-Fermi electronic distribution within the colloidal particles. Transient absorption from these ?hot? electrons led to different absorptions from that of the plasmon absorption of ?cold? electrons. The ?hot? electrons relax via electron?phonon coupling in 2.5 ps, and the phonon?phonon relaxation of the lattice occurs in >50 ps. At 380 nm excitation, the amplitude of the blue wing becomes smaller, and the slow component becomes longer, which could be due to possible excitation of the d-band electrons. These results are discussed in terms of Mie theory and a two-temperature model (TTM), and their consequences on the optical absorption spectrum.Colloidal gold nanoparticles with an average radius of 15 nm have a surface plasmon absorption band at 530 nm. Excitation by laser pulses of 450 fs duration, and wavelength of 600 or 380 nm ?bleached? the plasmon band and produced a transient absorption at the wings of the ?bleach? spectrum. The transient absorption was found to have a similar temporal behavior at different wavelengths. Analysis of their temporal behavior showed two time constants:? 2.5 ps, and a slower component of >50 ps. Laser excitation close to the plasmon band at 600 nm leads to the formation of ?hot? non-Fermi electronic distribution within the colloidal particles. Transient absorption from these ?hot? electrons led to different absorptions from that of the plasmon absorption of ?cold? electrons. The ?hot? electrons relax via electron?phonon coupling in 2.5 ps, and the phonon?phonon relaxation of the lattice occurs in >50 ps. At 380 nm excitation, the amplitude of the blue wing becomes smaller, and the slow component becomes longer, which could be due to possible excitation of the d-band electrons. These results are discussed in terms of Mie theory and a two-temperature model (TTM), and their consequences on the optical absorption spectrum. PB - American Chemical Society VL - 100 SN - 0022-3654 UR - http://dx.doi.org/10.1021/jp960484e CP - 20 N1 - doi: 10.1021/jp960484e J1 - J. Phys. Chem. ER - TY - JOUR T1 - Shape-Controlled Synthesis of Colloidal Platinum Nanoparticles JF - Science (New York, N.Y.) Y1 - 1996 A1 - Ahmadi, Temer S. A1 - Wang, Z.L. A1 - Green, T.C. A1 - Henglein, A. A1 - El-Sayed, Mostafa A AB - 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. VL - 272 CP - 5270 U1 - http://www.ncbi.nlm.nih.gov/pubmed/8662492?dopt=Abstract M3 - 10.1126/science.272.5270.1924 ER - TY - JOUR T1 - Comparison between the Binding of Ca2+ and Mg2+ to the Two High-Affinity Sites of Bacteriorhodopsin JF - The Journal of Physical Chemistry Y1 - 1995 A1 - Yoo, Seoung-Kyo A1 - Awad, Elias S. A1 - El-Sayed, Mostafa A AB - See http://dx.doi.org/10.1021/j100029a043 for article's front page in lieu of an abstract PB - American Chemical Society VL - 99 SN - 0022-3654 UR - http://dx.doi.org/10.1021/j100029a043 CP - 29 N1 - doi: 10.1021/j100029a043 J1 - J. Phys. Chem. M3 - doi: 10.1021/j100029a043 ER - TY - JOUR T1 - Dynamics of Formation and Evaporation of Mixed Alkali Halide Nanocrystals: A Case of Comparable Lattice Energies JF - The Journal of Physical Chemistry Y1 - 1994 A1 - Ahmadi, Temer S. A1 - El-Sayed, Mostafa A AB - View http://dx.doi.org/10.1021/j100095a013 for article's front page in lieu of an abstract PB - American Chemical Society VL - 98 SN - 0022-3654 UR - http://dx.doi.org/10.1021/j100095a013 CP - 44 N1 - doi: 10.1021/j100095a013 J1 - J. Phys. Chem. M3 - doi: 10.1021/j100095a013 ER -