%0 Journal Article %J Proceedings of the National Academy of Sciences %D 2017 %T A force for Egyptian science %A El-Sayed, Mostafa A. %A Zewail, Ahmed %B Proceedings of the National Academy of Sciences %G eng %0 Journal Article %J Journal of the American Chemical Society %D 2016 %T Hyperoxia Induces Intracellular Acidification in Neonatal Mouse Lung Fibroblasts: Real-Time Investigation Using Plasmonically Enhanced Raman Spectroscopy %A Panikkanvalappil, Sajanlal R. %A James, Masheika %A Hira, Steven M %A Mobley, James %A Jilling, Tamas %A Ambalavanan, Namasivayam %A El-Sayed, Mostafa A. %B Journal of the American Chemical Society %V 138 %P 3779–3788 %G eng %0 Journal Article %J Journal of the American Chemical Society %D 2016 %T A Real-Time Surface Enhanced Raman Spectroscopy Study of Plasmonic Photothermal Cell Death Using Targeted Gold Nanoparticles %A Aioub, Mena S %A El-Sayed, Mostafa A. %B Journal of the American Chemical Society %G eng %0 Journal Article %J The Journal of Physical Chemistry C %D 2016 %T The Sensitivity of the Distance Dependent Plasmonic Coupling between Two Nanocubes to their Orientation: Edge-to-Edge versus Face-to-Face %A Hooshmand, Nasrin %A Bordley, Justin A %A El-Sayed, Mostafa A. %B The Journal of Physical Chemistry C %V 120 %P 4564–4570 %G eng %0 Journal Article %J Journal of Physical Chemistry B %D 2016 %T Virtual Issue in Memory of Ahmed Zewail %A El-Sayed, Mostafa A. %A Schatz, GC %B Journal of Physical Chemistry B %G eng %0 Journal Article %J Nano Letters %D 2015 %T The Coupling between Gold or Silver Nanocubes in Their Homo-Dimers: A New Coupling Mechanism at Short Separation Distances %A Bordley, Justin A %A Hooshmand, Nasrin %A El-Sayed, Mostafa A. %B Nano Letters %V 15 %P 3391-3397 %G eng %U http://dx.doi.org/10.1021/acs.nanolett.5b00734 %R 10.1021/acs.nanolett.5b00734 %0 Journal Article %J Toxicology in Vitro %D 2015 %T Cytotoxic effects of cytoplasmic-targeted and nuclear-targeted gold and silver nanoparticles in HSC-3 cells–A mechanistic study %A Lauren A. Austin %A Ahmad, Samera %A Kang, Bin %A Rommel, Kathryn R %A Mahmoud, Mahmoud %A Peek, Mary E %A El-Sayed, Mostafa A. %B Toxicology in Vitro %V 29 %P 694–705 %G eng %0 Journal Article %J Photochemistry and Photobiology %D 2015 %T Electronic and Vibrational Dynamics of Hollow Au Nanocages Embedded in Cu2O Shells %A Szymanski, Paul %A Mahmoud, Mahmoud A. %A O'Neil, Daniel %A Garlyyev, Batyr %A El-Sayed, Mostafa A. %B Photochemistry and Photobiology %V 91 %P 599–606 %G eng %U http://dx.doi.org/10.1111/php.12432 %R 10.1111/php.12432 %0 Journal Article %J ACS Appl Mater Interfaces %D 2015 %T Light-responsive plasmonic arrays consisting of silver nanocubes and a photoisomerizable matrix. %A Ledin, Petr A %A Russell, Michael %A Geldmeier, Jeffrey A %A Tkachenko, Ihor M %A Mahmoud, Mahmoud A. %A Shevchenko, Valery %A El-Sayed, Mostafa A. %A Tsukruk, Vladimir V. %X We report on the synthesis of novel branched organic-inorganic azo-polyhedral oligomeric silsesquioxane (POSS) conjugates (Azo-POSS) and their use as a stable active medium to induce reversible plasmonic modulations of embedded metal nanostructures. A dense monolayer of silver nanocubes was deposited on a quartz substrate using the Langmuir-Blodgett technique and subsequently coated with an ultrathin Azo-POSS layer. The reversible light-induced photoisomerization between the trans and cis states of the azobenzene-terminated branched POSS material results in significant changes in the refractive index (up to 0.17) at a wavelength of 380 nm. We observed that the pronounced and reversible change in the surrounding refractive index results in a corresponding hypsochromic plasmonic shift of 6 nm in the plasmonic band of the embedded silver nanocubes. The reversible tuning of the plasmonic modes of noble-metal nanostructures using a variable-refractive-index medium opens up the possibility of fabricating photoactive, hybrid, ultrathin coatings with robust, real-time, photoinitiated responses for prospective applications in photoactive materials that can be reversibly tuned by light illumination. %B ACS Appl Mater Interfaces %V 7 %P 4902-12 %8 2015 Mar 4 %G eng %N 8 %1 http://www.ncbi.nlm.nih.gov/pubmed/25671557?dopt=Abstract %R 10.1021/am508993z %0 Journal Article %J Chemistry of Materials %D 2015 %T Near-Infrared Asymmetrical Squaraine Sensitizers for Highly Efficient Dye Sensitized Solar Cells: The Effect of π-Bridges and Anchoring Groups on Solar Cell Performance %A Fadi M. Jradi %A Xiongwu Kang %A O’Neil, Daniel %A Gabriel Pajares %A Yulia A. Getmanenko %A Szymanski, Paul %A Timothy C. Parker %A El-Sayed, Mostafa A. %A Seth R. Marder %B Chemistry of Materials %V 27 %P 2480-2487 %G eng %U http://dx.doi.org/10.1021/cm5045946 %R 10.1021/cm5045946 %0 Journal Article %J The Journal of Physical Chemistry C %D 2015 %T Plasmonic Spectroscopy: The Electromagnetic Field Strength and its Distribution Determine the Sensitivity Factor of Face-to-Face Ag Nanocube Dimers in Solution and on a Substrate %A Hooshmand, Nasrin %A Bordley, Justin A %A El-Sayed, Mostafa A. %B The Journal of Physical Chemistry C %V 119 %P 15579-15587 %G eng %U http://dx.doi.org/10.1021/acs.jpcc.5b05395 %R 10.1021/acs.jpcc.5b05395 %0 Journal Article %J Nano Today %D 2015 %T Probing molecular cell event dynamics at the single-cell level with targeted plasmonic gold nanoparticles: A review %A Lauren A. Austin %A Bing Kang %A El-Sayed, Mostafa A. %K Rayleigh scattering %B Nano Today %P - %G eng %U http://www.sciencedirect.com/science/article/pii/S1748013215000973 %R http://dx.doi.org/10.1016/j.nantod.2015.07.005 %0 Journal Article %J Nanoscale %D 2015 %T Silver nanocube aggregation gradient materials in search for total internal reflection with high phase sensitivity %A Konig, Tobias A. F. %A Ledin, Petr A %A Russell, Michael %A Geldmeier, Jeffrey A %A Mahmoud, Mahmoud. A. %A El-Sayed, Mostafa A. %A Tsukruk, Vladimir V. %X We fabricated monolayer coatings of a silver nanocube aggregation to create a step-wise optical strip by applying different surface pressures during slow Langmuir-Blodgett deposition. The varying amount of randomly distributed nanocube aggregates with different surface coverages in gradient manner due to changes in surface pressure allows for continuous control of the polarization sensitive absorption of the incoming light over a broad optical spectrum. Optical characterization under total internal reflection conditions combined with electromagnetic simulations reveal that the broadband light absorption depends on the relative orientation of the nanoparticles to the polarization of the incoming light. By using computer simulations, we found that the electric field vector of the s-polarized light interacts with the different types of silver nanocube aggregations to excite different plasmonic resonances. The s-polarization shows dramatic changes of the plasmonic resonances at different angles of incidence (shift of 64 nm per 10[degree] angle of incidence). With a low surface nanocube coverage (from 5% to 20%), we observed a polarization-selective high absorption of 80% (with an average 75%) of the incoming light over a broad optical range in the visible region from 400 nm to 700 nm. This large-area gradient material with location-dependent optical properties can be of particular interest for broadband light absorption, phase-sensitive sensors, and imaging. %B Nanoscale %V 7 %P 5230-5239 %G eng %U http://dx.doi.org/10.1039/C4NR06430E %R 10.1039/C4NR06430E %0 Journal Article %J The Journal of Physical Chemistry C %D 2015 %T Wavelength-Selective Photocatalysis Using Gold–Platinum Nanorattles %A Mahmoud, Mahmoud A. %A Garlyyev, Batyr %A El-Sayed, Mostafa A. %B The Journal of Physical Chemistry C %V 119 %P 18618-18626 %G eng %U http://dx.doi.org/10.1021/acs.jpcc.5b05967 %R 10.1021/acs.jpcc.5b05967 %0 Journal Article %J The Journal of Physical Chemistry Letters %D 2014 %T Are hot spots between two plasmonic nanocubes of silver or gold formed between adjacent corners or adjacent facets? A DDA examination %A Hooshmand, Nasrin %A El-Sayed, Mostafa A. %A Bordley, Justin A %B The Journal of Physical Chemistry Letters %@ 1948-7185 %G eng %0 Journal Article %J ACS nano %D 2014 %T Electrically Tunable Plasmonic Behavior of Nanocube-Polymer Nanomaterials Induced by a Redox Active Electrochromic Polymer %A König, Tobias AF %A Ledin, Petr A %A Kerszulis, Justin %A Mahmoud, Mahmoud A. %A El-Sayed, Mostafa A. %A Reynolds, John R %A Tsukruk, Vladimir V. %B ACS nano %@ 1936-0851 %G eng %! ACS Nano %0 Journal Article %J Journal of the American Chemical Society %D 2014 %T Enhancing the Efficiency of Gold Nanoparticles Treatment of Cancer by Increasing Their Rate of Endocytosis and Cell Accumulation Using Rifampicin %A Ali, Moustafa RK %A Panikkanvalappil, Sajanlal R. %A El-Sayed, Mostafa A. %B Journal of the American Chemical Society %V 136 %P 4464-4467 %@ 0002-7863 %G eng %! J Am Chem Soc %0 Journal Article %J Energy & Environmental Science %D 2014 %T High-temperature surface enhanced Raman spectroscopy for in situ study of solid oxide fuel cell materials %A Li, Xiaxi %A Lee, Jung-Pil %A Blinn, Kevin S %A Chen, Dongchang %A Yoo, Seungmin %A Kang, Bin %A Bottomley, Lawrence A %A El-Sayed, Mostafa A. %A Park, Soojin %A Liu, Meilin %B Energy & Environmental Science %V 7 %P 306-310 %G eng %0 Journal Article %J ACS nano %D 2014 %T Observing Real-Time Molecular Event Dynamics of Apoptosis in Living Cancer Cells using Nuclear-Targeted Plasmonically Enhanced Raman Nanoprobes %A Kang, Bin %A Austin, Lauren %A El-Sayed, Mostafa A. %B ACS nano %V 8 %P 4883-4892 %@ 1936-0851 %G eng %! ACS Nano %0 Journal Article %J Archives of Toxicology %D 2014 %T The optical, photothermal, and facile surface chemical properties of gold and silver nanoparticles in biodiagnostics, therapy, and drug delivery %A Austin, Lauren %A Mackey, Megan A. %A Dreaden, Erik C. %A El-Sayed, Mostafa A. %B Archives of Toxicology %P 1-27 %@ 0340-5761 %G eng %! Arch. Toxicol. %0 Journal Article %J ACS nano %D 2014 %T Self-Assembled Nanostructured Photoanodes with Staggered Bandgap for Efficient Solar Energy Conversion %A Nashed, Ramy %A Szymanski, Paul %A El-Sayed, Mostafa A. %A Allam, Nageh K %B ACS nano %@ 1936-0851 %G eng %! ACS Nano %0 Journal Article %J The Journal of Physical Chemistry A %D 2014 %T The Spectroscopy of Homo and Heterodimers of Silver and Gold Nanocubes as a Function of Separation: a DDA Simulation %A Hooshmand, Nasrin %A O'Neil, Daniel %A Asiri, Abdullah M %A El-Sayed, Mostafa A. %B The Journal of Physical Chemistry A %@ 1089-5639 %G eng %0 Journal Article %J The Journal of Physical Chemistry C %D 2014 %T Stacked Gold Nanorectangles with Higher Order Plasmonic Modes and Top-Down Plasmonic Coupling %A Malak, Sidney T. %A König, Tobias %A Near, Rachel %A Combs, Zachary A. %A El-Sayed, Mostafa A. %A Tsukruk, Vladimir V. %B The Journal of Physical Chemistry C %V 118 %P 5453-5462 %@ 1932-7447 %G eng %0 Journal Article %J J. Mater. Chem. A %D 2013 %T Assemblies of silver nanocubes for highly sensitive SERS chemical vapor detection %A Kodiyath, Rajesh %A Malak, Sidney T. %A Combs, Zachary A. %A Koenig, Tobias %A Mahmoud, Mahmoud A. %A El-Sayed, Mostafa A. %A Tsukruk, Vladimir V. %K polymer electrolyte film silver nanocube nanosphere SERS sensor explosive %K porous alumina silver nanoparticle SERS substrate explosive %K silver nanocube nanosphere SERS sensor benzenethiol methyl nitroaniline polyelectrolyte %K vapor sensor silver nanoparticle SERS substrate %X Probably Ag nanocube (AgNC) aggregates within cylindrical pores (PAM-AgNC) can be employed as efficient nanostructures for highly efficient, robust, tunable, and reusable surface-enhanced Raman scattering (SERS) substrates for trace level org. vapor detection which is a challenging task in chem. detection. The authors demonstrate the ability to tune both the detection limit and the onset of signal satn. of the substrate by switching the adsorption behavior of AgNCs between highly aggregated and more disperse by varying the no. of adsorption-mediating polyelectrolyte bilayers on the pore walls of the membrane. The different AgNC distributions show large differences in the trace vapor detection limit of the common Raman marker benzenethiol (BT) and a widely used explosive binder N-Me-4-nitroaniline (MNA), demonstrating the importance of the large electromagnetic field enhancement assocd. with AgNC coupling. The SERS substrate with highly aggregated AgNCs within the cylindrical pores allows for consistent trace detection of mid ppb (∼500) for BT analyte, and a record limit of detection of low ppb (∼3) for MNA vapors with an estd. achievable limit of detection of ∼600 ppt. The dispersed AgNC aggregates do not sat. at higher ppb concns., providing an avenue to distinguish between higher ppb concns. and increase the effective range of the SERS substrate design. A comparison between the AgNC substrate and an electroless deposition substrate with Ag quasi-nanospheres (PAM-AgNS) also demonstrates a higher SERS activity, and better detection limit, by the nanocube aggregates. This is supported by FDTD electromagnetic simulations that suggest that the higher integrated electromagnetic field intensity of the hot spots and the large specific interfacial areas impart greatly improved SERS for the AgNCs. Also, the AgNC substrate can be reused multiple times without significant loss of SERS activity which opens up new avenues for in-field monitoring. [on SciFinder(R)] %B J. Mater. Chem. A %I Royal Society of Chemistry %V 1 %P 2777-2788 %8 // %@ 2050-7496 %G eng %9 10.1039/c2ta00867j %R 10.1039/c2ta00867j %0 Journal Article %J The Journal of Physical Chemistry C %D 2013 %T Electron transfer process in fluorescein-dispersing titania gel films observed by time-resolved fluorescence spectroscopy %A Setiawan, Rudi Agus %A Nishikiori, Hiromasa %A Uesugi, Yohei %A Miyashita, Kyohei %A El-Sayed, Mostafa A. %A Fujii, Tsuneo %B The Journal of Physical Chemistry C %V 117 %P 10308-10314 %@ 1932-7447 %G eng %0 Journal Article %J Acc Chem Res %D 2013 %T Enhancing Colloidal Metallic Nanocatalysis: Sharp Edges and Corners for Solid Nanoparticles and Cage Effect for Hollow Ones %A Mahmoud, Mahmoud A. %A Narayanan, Radha %A El-Sayed, Mostafa A. %X There are two main classes of metallic nanoparticles: solid and hollow. Each type can be synthesized in different shapes and structures. Practical use of these nanoparticles depends on the properties they acquire on the nanoscale. Plasmonic nanoparticles of silver and gold are the most studied, with applications in the fields of sensing, medicine, photonics, and catalysis. In this Account, we review our group's work to understand the catalytic properties of metallic nanoparticles of different shapes. Our group was the first to synthesize colloidal metallic nanoparticles of different shapes and compare their catalytic activity in solution. We found that the most active among these were metallic nanoparticles having sharp edges, sharp corners, or rough surfaces. Thus, tetrahedral platinum nanoparticles are more active than spheres. We proposed this happens because sharper, rougher particles have more valency-unsatisfied surface atoms (i.e., atoms that do not have the complete number of bonds that they can chemically accommodate) to act as active sites than smoother nanoparticles. We have not yet resolved whether these catalytically active atoms act as catalytic centers on the surface of the nanoparticle (i.e., heterogeneous catalysis) or are dissolved by the solvent and perform the catalysis in solution (i.e., homogenous catalysis). The answer is probably that it depends on the system studied. In the past few years, the galvanic replacement technique has allowed synthesis of hollow metallic nanoparticles, often called nanocages, including some with nested shells. Nanocage catalysts show strong catalytic activity. We describe several catalytic experiments that suggest the reactions occurred within the cage of the hollow nanocatalysts: (1) We synthesized two types of hollow nanocages with double shells, one with platinum around palladium and the other with palladium around platinum, and two single-shelled nanocages, one made of pure platinum and the other made of pure palladium. The kinetic parameters of each double-shelled catalyst were comparable to those of the single-shelled nanocage of the same metal as the inside shell, which suggests the reactions are taking place inside the cavity. (2) In the second set of experiments, we used double-shelled, hollow nanoparticles with a plasmonic outer gold surface and a non-plasmonic inner catalytic layer of platinum as catalysts. As the reaction proceeded and the dielectric function of the interior gold cavity changed, the plasmonic band of the interior gold shell shifted. This strongly suggested that the reaction had taken place in the nanocage. (3) Finally, we placed a catalyst on the inside walls of hollow nanocages and monitored the corresponding reaction over time. The reaction rate depended on the size and number of holes in the walls of the nanoparticles, strongly suggesting the confinement effect of a nanoreactor.[on SciFinder (R)] %B Acc Chem Res %8 // %@ 1520-4898 %G eng %0 Journal Article %J Chemistry of Materials %D 2013 %T Hollow and Solid Metallic Nanoparticles in Sensing and in Nanocatalysis %A Mahmoud, Mahmoud A. %A O’Neil, Daniel %A El-Sayed, Mostafa A. %B Chemistry of Materials %V 26 %P 44-58 %@ 0897-4756 %G eng %! Chem Mater %0 Journal Article %J J Am Chem Soc %D 2013 %T A New Nanotechnology Technique for Determining Drug Efficacy Using Targeted Plasmonically Enhanced Single Cell Imaging Spectroscopy %A Austin, Lauren %A Kang, Bin %A El-Sayed, Mostafa A. %X 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)] %B J Am Chem Soc %8 // %@ 1520-5126 %G eng %0 Journal Article %J J Am Chem Soc %D 2013 %T Probing the unique dehydration-induced structural modifications in cancer cell DNA using surface enhanced Raman spectroscopy %A Panikkanvalappil, Sajanlal R. %A Mackey, Megan A. %A El-Sayed, Mostafa A. %X Conformation-induced formation of a series of unique Raman marker bands in cancer cell DNA, upon dehydration, have been probed for the first time with the use of surface enhanced Raman spectroscopy (SERS). These bands are capable of distinguishing cancer cell DNA from healthy cell DNA. For this simple and label-free DNA detection approach, we used conventional spherical silver nanoparticles, at a high concentration, without any aggregating agents, which gave highly reproducible SERS spectra of DNA separated from various human cells irrespective of their highly complex compositions and sequences. The observed phenomenon is attributed to the change in the chemical environment due to the presence of nucleobase lesions in cancer cell DNA and subsequent variation in the nearby electronic cloud during the dehydration-driven conformational changes. Detailed analysis of the SERS spectra gives important insight about the lesion-induced structural modifications upon dehydration in the cancer cell DNA. These results have widespread implications in cancer diagnostics, where SERS provides vital information about the DNA modifications in the cancer cells.[on SciFinder (R)] %B J Am Chem Soc %8 // %@ 1520-5126 %G eng %0 Journal Article %J Small %D 2013 %T Surface Assembly and Plasmonic Properties in Strongly Coupled Segmented Gold Nanorods %A Gupta, Maneesh K. %A Konig, Tobias %A Near, Rachel %A Nepal, Dhriti %A Drummy, Lawrence F. %A Biswas, Sushmita %A Naik, Swati %A Vaia, Richard A. %A El-Sayed, Mostafa A. %A Tsukruk, Vladimir V. %X An assembly strategy is reported such that segmented nanorods fabricated through template-assisted methods can be robustly transferred and tethered to a pre-functionalized substrate with excellent uniformity over large surface areas. After embedding the rods, sacrificial nickel segments were selectively etched leaving behind strongly coupled segmented gold nanorods with gaps between rods below 40 nm and as small as 2 nm. Hyper-spectral imaging is utilized to measure Rayleigh scattering spectra from individual and coupled nanorod elements in contrast to common bulk measurements. This approach discerns the effects of not only changing segment and gap size but also the presence of characteristic defects on the plasmonic coupling between closely spaced nanorods. Polarized hyper-spectral measurements are conducted to provide direct observation of the anisotropic plasmonic resonance modes in individual and coupled nanorods, which are close to those predicted by computer simulations for nanorods with ideal shapes. Some common deviations from ideal shape such as non-flat facets and asymmetric tails are demonstrated to result in the appearance of characteristic plasmon resonances, which have not been considered before. The large-scale assembly of coupled noble nanostructures with fine control over geometry and high uniformity provides means to strongly tune the scattering, absorption, and near-field plasmonic properties through the geometric arrangement of precisely controlled nanorod segments.[on SciFinder (R)] %B Small %8 // %@ 1613-6829 %G eng %0 Conference Proceedings %B SPIE Solar Energy+ Technology %D 2013 %T Towards a perfect system for solar hydrogen production: an example of synergy on the atomic scale %A Nashed, Ramy %A Alamgir, Faisal M %A Seung-Soon, Jang %A Ismail, Yehea %A El-Sayed, Mostafa A. %A Allam, Nageh %B SPIE Solar Energy+ Technology %I International Society for Optics and Photonics %P 88220A-88220A-7 %G eng %0 Conference Proceedings %B CANCER RESEARCH %D 2013 %T Toxicities and antitumor efficacy of tumor-targeted AuNRs in mouse model %A Peng, Xianghong %A Mackey, Megan %A Austin, Lauren %A Oyelere, Adegboyega %A Chen, Georgia %A Huang, Xiaohua %A El-Sayed, Mostafa A. %A Shin, Dong M %B CANCER RESEARCH %I AMER ASSOC CANCER RESEARCH 615 CHESTNUT ST, 17TH FLOOR, PHILADELPHIA, PA 19106-4404 USA %V 73 %@ 0008-5472 %G eng %! Cancer Res. %0 Journal Article %J Nanoscale %D 2013 %T Well-organized raspberry-like Ag@ Cu bimetal nanoparticles for highly reliable and reproducible surface-enhanced Raman scattering %A Lee, Jung-Pil %A Chen, Dongchang %A Li, Xiaxi %A Yoo, Seungmin %A Bottomley, Lawrence A %A El-Sayed, Mostafa A. %A Park, Soojin %A Liu, Meilin %B Nanoscale %V 5 %P 11620-11624 %G eng %0 Journal Article %J J. Nanomed. Nanotechnol. %D 2012 %T 5-Fluorouracil induces plasmonic coupling in gold nanospheres: new generation of chemotherapeutic agents %A Mohamed, Mona B. %A Adbel-Ghani, Nour T. %A El-Borady, Ola M. %A El-Sayed, Mostafa A. %X 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)] %B J. Nanomed. Nanotechnol. %I OMICS Publishing Group %V 3 %P 1000146/1-1000146/7 %8 // %@ 2157-7439 %G eng %9 10.4172/2157-7439.1000146 %R 10.4172/2157-7439.1000146 %0 Journal Article %J Ther. Delivery %D 2012 %T Size matters: gold nanoparticles in targeted cancer drug delivery %A Dreaden, Erik C. %A Austin, Lauren %A Mackey, Megan A. %A El-Sayed, Mostafa A. %K review gold nanoparticle targeted cancer drug delivery %X 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)] %B Ther. Delivery %I Future Science Ltd. %V 3 %P 457-478 %8 // %@ 2041-5990 %G eng %9 10.4155/tde.12.21 %R 10.4155/tde.12.21 %0 Journal Article %J Lasers in Medical Science %D 2008 %T Plasmonic photothermal therapy (PPTT) using gold nanoparticles %A Huang, Xiaohua %A Jain, Prashant K %A El Sayed, I.H. %A El-Sayed, Mostafa A. %K display %X The use of lasers, over the past few decades, has emerged to be highly promising for cancer therapy modalities, most commonly the photothermal therapy method, which employs light absorbing dyes for achieving the photothermal damage of tumors, and the photodynamic therapy, which employs chemical photosensitizers that generate singlet oxygen that is capable of tumor destruction. However, recent advances in the field of nanoscience have seen the emergence of noble metal nanostructures with unique photophysical properties, well suited for applications in cancer phototherapy. Noble metal nanoparticles, on account of the phenomenon of surface plasmon resonance, possess strongly enhanced visible and near-infrared light absorption, several orders of magnitude more intense compared to conventional laser phototherapy agents. The use of plasmonic nanoparticles as highly enhanced photoabsorbing agents has thus introduced a much more selective and efficient cancer therapy strategy, viz. plasmonic photothermal therapy (PPTT). The synthetic tunability of the optothermal properties and the bio-targeting abilities of the plasmonic gold nanostructures make the PPTT method furthermore promising. In this review, we discuss the development of the PPTT method with special emphasis on the recent in vitro and in vivo success using gold nanospheres coupled with visible lasers and gold nanorods and silica-gold nanoshells coupled with near-infrared lasers. %B Lasers in Medical Science %V 23 %P 217-228 %8 Jul %@ 0268-8921 %G eng %M WOS:000256912200001 %R 10.1007/s10103-007-0470-x %0 Journal Article %J Journal of the American Chemical Society %D 2006 %T Cancer cell imaging and photothermal therapy in the near-infrared region by using gold nanorods %A Huang, Xiaohua %A El Sayed, I.H. %A Qian, Wei %A El-Sayed, Mostafa A. %K display %X Due to strong electric fields at the surface, the absorption and scattering of electromagnetic radiation by noble metal nanoparticles are strongly enhanced. These unique properties provide the potential of designing novel optically active reagents for simultaneous molecular imaging and photothermal cancer therapy. It is desirable to use agents that are active in the near-infrared (NIR) region of the radiation spectrum to minimize the light extinction by intrinsic chromophores in native tissue. Gold nanorods with suitable aspect ratios (length divided by width) can absorb and scatter strongly in the NIR region (650-900 nm). In the present work, we provide an in vitro demonstration of gold nanorods as novel contrast agents for both molecular imaging and photothermal cancer therapy. Nanorods are synthesized and conjugated to anti-epidermal growth factor receptor (anti-EGFR) monoclonal antibodies and incubated in cell cultures with a nonmalignant epithelial cell line (HaCat) and two malignant oral epithelial cell lines (HOC 313 clone 8 and HSC 3). The anti-EGFR anti body-conjugated nanorods bind specifically to the surface of the malignant-type cells with a much higher affinity due to the overexpressed EGFR on the cytoplasmic membrane of the malignant cells. As a result of the strongly scattered red light from gold nanorods in dark field, observed using a laboratory microscope, the malignant cells are clearly visualized and diagnosed from the nonmalignant cells. It is found that, after exposure to continuous red laser at 800 nm, malignant cells require about half the laser energy to be photothermally destroyed than the nonmalignant cells. Thus, both efficient cancer cell diagnostics and selective photothermal therapy are realized at the same time. %B Journal of the American Chemical Society %V 128 %P 2115-2120 %8 Feb %@ 0002-7863 %G eng %M WOS:000235452200054 %R 10.1021/ja057254a %0 Journal Article %J Nano Letters %D 2005 %T Surface plasmon resonance scattering and absorption of anti-EGFR antibody conjugated gold nanoparticles in cancer diagnostics: Applications in oral cancer %A El Sayed, I.H. %A Huang, Xiaohua %A El-Sayed, Mostafa A. %K display %X Gold nanoparticles with unique optical properties may be useful as biosensors in living whole cells. Using a simple and inexpensive technique, we recorded surface plasmon resonance (SPR) scattering images and SPR absorption spectra from both colloidal gold nanoparticles and from gold nanoparticles conjugated to monoclonal anti-epidermal growth factor receptor (anti-EGFR) antibodies after incubation in cell cultures with a nonmalignant epithelial cell line (HaCaT) and two malignant oral epithelial cell lines (HOC 313 clone 8 and HSC 3). Colloidal gold nanoparticles are found in dispersed and aggregated forms within the cell cytoplasm and provide anatomic labeling information, but their uptake is nonspecific for malignant cells. The anti-EGFR antibody conjugated nanoparticles specifically and homogeneously bind to the surface of the cancer type cells with 600% greater affinity than to the noncancerous cells. This specific and homogeneous binding is found to give a relatively sharper SPR absorption band with a red shifted maximum compared to that observed when added to the noncancerous cells. These results suggest that SPR scattering imaging or SPR absorption spectroscopy generated from antibody conjugated gold nanoparticles can be useful in molecular biosensor techniques for the diagnosis and investigation of oral epithelial living cancer cells in vivo and in vitro. %B Nano Letters %V 5 %P 829-834 %8 May %@ 1530-6984 %G eng %M WOS:000229120900003 %R 10.1021/nl050074e %0 Journal Article %J Chem. Soc. Rev. %D 2005 %T Why gold nanoparticles are more precious than pretty gold: Noble metal surface plasmon resonance and its enhancement of the radiative and nonradiative properties of nanocrystals of different shapes %A Eustis, Susie %A El-Sayed, Mostafa A. %K display %X This tutorial review presents an introduction to the field of noble metal nanoparticles and their current applications. The origin of the surface plasmon resonance and synthesis procedures are described. A number of applications are presented that take advantage of the electromagnetic field enhancement of the radiative properties of noble metal nanoparticles resulting from the surface plasmon oscillations. %B Chem. Soc. Rev. %I The Royal Society of Chemistry %V 35 %P 209-217 %G eng %N 3 %R 10.1039/B514191E