Mostafa A El-Sayed

• PhD
• Chair at Georgia Institute of Technology

Chemo-photothermal therapy has attracted extensive research attention because of its synergistic effect in destroying cancer cells, which makes it one of the most effective treatments. Gold nanorods conjugated with thiolated beta-cyclodextrin loaded with doxorubicin (DOX), AuNRs@S-β-CD-DOX nanocomposite, for intracellular delivery were designed to...

Phase-change materials (PCMs) offer a compelling platform for active metaoptics, owing to their large index contrast and fast yet stable phase transition attributes. Despite recent advances in phase-change metasurfaces, a fully integrable solution that combines pronounced tuning measures, i.e., efficiency, dynamic range, speed, and power consumptio...

Combination nanodrugs are promising therapeutic agents for cancer treatment. However, they often require the use of complex nanovehicles for transportation into the tumor site. Herein, a new class of carrier-free ionic nanomaterials (INMs) is presented, which are self-assembled by the drug molecules themselves. In this regard, a photothermal therap...

We designed novel biocompatible nanocomposite composed of gold nanorods coated with rod-like mesoporous silica SBA-15-SH particles, (GNRs@SBA-15-SH) as a new synergistic therapeutic device to deliver heat and drug to cancer cells for tumor eradication. For this purpose, doxorubicin (DOX) was loaded into GNRs@SBA-15-SH nanocomposites and studied the...

Lung failure is the main reason for mortality in COVID-19 patients, caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). To date, no drug has been clinically approved for treatment of COVID-19. Nanotechnology has a great potential in contributing significantly to the fight against COVID-19 by developing effective therapies th...

Efficient hybrid plasmonic-photonic metasurfaces that simultaneously take advantage of the potential of both pure metallic and all-dielectric nanoantennas are identified as an emerging technology in flat optics. Nevertheless, postfabrication tunable hybrid metasurfaces are still elusive. Here, we present a reconfigurable hybrid metasurface platform...

Cost-effective production of ammonia via electrochemical nitrogen reduction reaction (NRR) hinges on N2 electrolysis at high current densities with suitable selectivity and activity. Here we report our findings in electrochemical NRR for ammonia synthesis using porous bimetallic Pd-Ag nanocatalysts in both gas-phase and liquid-phase electrochemical...

Efficient hybrid plasmonic-photonic metasurfaces that simultaneously take advantage of the potential of both pure metallic and all-dielectric nanoantennas are identified as an emerging technology in flat optics. Nevertheless, post-fabrication tunable hybrid metasurfaces are still elusive. Here, we present a reconfigurable hybrid metasurface platfor...

Development of optical nanobiosensors is one of the important priorities especially in the field of biomedical diagnostics science and technology. The application of nanobiosensors has been accelerated with the introduction of plasmonic NPs, which overcome the most of the limitations in the case of conventional optical nanobiosensors. Since the pla...

Electrosynthesis of ammonia using nitrogen and water provides a potential alternative to the thermochemical process (Haber-Bosch) in a clean, sustainable, and decentralized way when electricity is generated from renewable sources. To enable the widespread commercialization of this technology, an electrocatalyst to convert nitrogen (N2) to ammonia (...

The photocatalyst titania film surface acquires a high hydrophilicity after it is exposed to UV light, which is induced by changes in the densities of the surface hydroxyl groups and charge. A xanthene dye, fluorescein, was deposited from a solution onto a titania film after UV irradiation in order to probe the titania surface change. The change in...

Background: Gold nanoparticles (AuNPs) with unique physicochemical properties have received a great deal of interest in the field of biological, chemical and biomedical implementations. Despite the widespread use of AuNPs in chemical and biological sensing, catalysis, imaging and diagnosis, and more recently in therapy, no comprehensive summary has...

We study the in-situ electrochemically modulated dark-field scattering of a gold nanoparticle coated with poly(3,4-ethylenedioxythiophene) (PEDOT) shell, allowing for the visualization of the redox state of PEDOT down to a single nanoparticle level. The presence of the gold nanoparticle as a core dramatically increases scattering cross-section, whi...

Due to the considerable amount of applications of gold nanoparticles (AuNPs) in biological systems, there is a great need for an improved methodology to quantitatively measure the uptake of AuNPs in cells. Flow cytometry has the ability to meas-ure intracellular AuNPs by collecting the light scattering from a large population of live cells through...

Significance We present a systematic study of the effect of higher-multipolar order plasmon modes on the spectral response and plasmonic coupling of Ag nanoparticle dimers at nanojunction separation and introduce a coupling mechanism. It was found that as the interdimer axis decreases, an increase in the plasmon dipolar and multipolar interaction t...

Photo(electro)catalytic N2 fixation with water under ambient conditions offers an ideal pathway for clean, sustainable, and decentralized ammonia production and might serve as a potential alternative to the capital and energy intensive Haber-Bosch process. To date, almost all photocatalysts for nitrogen reduction reaction (NRR) suffer from poor sel...

For localized tumors, gold nanorod (AuNR)-assisted plasmonic photothermal therapy (PPTT) is a potentially effective alternative to traditional surgery, in which AuNRs absorb near-infrared light and convert it to heat in order to kill cancer cells. However, for large tumors (volume ≥ 20 cm 3), an uneven distribution of AuNRs might cause inhomogeneit...

Plasmonic photothermal therapy (PPTT), a type of treatment involving the intravenous or intratumoral injection to introduce gold nanoparticles to cancerous cells and the subsequent exposure to heat-generating near infrared (NIR) light is a potentially favorable alternative to traditional treatments of localized tumors such as chemotherapy, radiothe...

Electrochemical ammonia synthesis from nitrogen and water provides an alternative route to the thermochemical process (Haber-Bosch) in a clean, sustainable, and decentralized way if electricity is generated from renewable sources. We have previously demonstrated the use of bimetallic hollow Au-Ag nanocages as an effective electrocatalyst for electr...

Electrochemical ammonia synthesis from nitrogen and water provides an alternative route to the thermochemical process (Haber-Bosch) in a clean, sustainable, and decentralized way if electricity is generated from renewable sources. We previously demonstrated the use of bimetallic hollow Au−Ag nanocages as an effective electrocatalyst for electrosynt...

We report for the first time the usage of plasmonically enhanced Raman spectroscopy (PERS) to directly monitor the dynamics of pharmacologically generated hemeoxygenase-1 (HO-1) by evaluating the kinetics of formation of carbon monoxide (CO), one of the metabolites of HO-1 activation, in live cells during cisplatin treatment. Being an endogenous si...

Optical imaging represents one of the most essential tools in biological studies. Although with great advances, bio-optical imaging still suffers from problems such as resolution, sensitivity, speed, and penetration depth. Due to the unique optical properties of gold nanoparticles (AuNPs), i.e., surface plasmon resonance, AuNPs can be readily used...

An electrochemical nitrogen reduction reaction (NRR) could provide an alternative pathway to the Haber-Bosch process for clean, sustainable, and decentralized NH3 production when it is coupled with renewably derived electricity sources. Developing an electrocatalyst that overcomes sluggish kinetics due to the challenges associated with N2 adsorptio...

Most cancer-related deaths come from metastasis. It was recently discovered that nanoparticles could inhibit cancer cell migration. While most researchers focus on single-cell migration, the effect of nanoparticle treatment on collective cell migration has not been explored. Collective migration occurs commonly in many types of cancer metastasis, w...

To date, a variety of biological assays such as immunostaining, Western blotting, enzyme-linked immunosorbent assay (ELISA), and flow cytometry have been used to analyze and trace important biological events and therapies. In addition to these techniques, the application of microscopic analytical techniques such as matrix-assisted laser desorption/...

Metastasis is the primary cause of cancer-related deaths. Current clinical treatments for anti-metastasis, however, are not effective. Gold nanorods (AuNRs), which are safe within biological systems, were recently discovered to inhibit cancer cell migration and prevent metastasis. However, the mechanism of how AuNRs inhibit cancer cell migration re...

We demonstrate that cellulose nanofiber (CNF) biomaterials with high transparency and mechanical robustness can be combined with gold nanorods to form a multifunctional porous membrane for dual-mode surface enhanced Raman scattering detection of both small molecules and cells. The nanoporous nature of the plasmonic nanofiber membranes allows for ef...

Ammonia production is imperative to increase the food supply for the growing global population. Ammonia is also considered a major hydrogen energy carrier. The current industrial method for ammonia production is energy intensive and heavily relies on fossil fuels, which are responsible for environmental pollution. To meet ammonia demands, it is nec...

As a noninvasive molecular analysis technique, ultraviolet resonance Raman (UVRR) spectroscopy represents a label‐free method suitable for characterizing biomolecules. Using UVRR spectroscopy, we collected spectral fingerprints of UV absorbing cellular components, including proteins, nucleic acids, and unsaturated lipids. This knowledge was used to...

Understanding the nature of interfacial defects of materials is a critical undertaking for the design of high-performance hybrid electrodes for photocatalysis applications. Theoretical and computational endeavors to achieve this have touched boundaries far ahead of their experimental counterparts. However, to achieve any industrial benefit out of s...

We report on electrochemically tunable hybrid nanostructures composed of gold nanorods encapsulated within directly polymerized poly[(3,4-propylenedioxy)pyrrole] (PProDOP) nanoshells with controlled nanoscale thicknesses. This system displays narrow visible-near infrared absorption bands upon applying a variable electric potential due to the remark...

Ultraviolet resonance Raman (UVRR) spectroscopy is a label-free method to define biomacromolecular interactions with anticancer compounds. Using UVRR, we describe the binding interactions of two Pt(II) compounds, cisplatin (cis-diamminedichloroplatinum(II)) and its isomer, transplatin, with nucleotides and genomic DNA. Cisplatin binds to DNA and ot...

To conquer cancer, one of the most dangerous and common diseases faced by humanity, many therapeutic approaches have been researched and developed. Among them, discovery of highly effective therapeutic molecules without side effects and novel strategies for their effective delivery are areas receiving recent global interest. Here, we described a fa...

Plasmonic Photothermal Therapy (PPTT) is a cancer therapy where gold nanorods (AuNRs) are injected at the tumor site and near-infrared light (safe to bio-system) is applied to generate localized heat causing cancer cell death. PPTT is a potentially good alternative to replace traditional surgery for localized tumors. However, for large tumors (volu...

Significance Metastasis is the primary cause of cancer-related deaths. Current clinical treatments for antimetastasis, however, are not effective. This work aims to develop a strategy to inhibit cancer cell migration using gold nanorods (AuNRs) with systematic understanding of the mechanism. The ability of targeting AuNRs to cancer cell surface int...

While T-Nb2O5 has been frequently reported to display an exceptionally fast rate of Li-ion storage (similar to a capacitor), the detailed mechanism of the energy storage process is yet to be unraveled. Here we report our findings in probing the nature of the ultrafast Li-ion storage in T-Nb2O5 using both experimental and computational approaches. E...

Plasmonic Photothermal Therapy (PPTT) is a cancer therapy where gold nanorods (AuNRs) are injected at the tumor site and near-infrared light (safe to bio-system) is applied to generate localized heat causing cancer cell death. PPTT is a potentially good alternative to replace traditional surgery for localized tumors. However, for large tumors (volu...

Significance This is a systematic in vivo study of gold nanorods (AuNRs)-assisted plasmonic photothermal therapy (AuNRs-PPTT) for cancer. We have optimized the properties of our AuNRs and the conditions of PPTT to achieve maximal induction of tumor apoptosis. To examine the molecular mechanisms of action of AuNRs-PPTT, we used quantitative proteomi...

Most cancer patients die from metastasis. Recent studies have shown that gold nanoparticles (AuNPs) can slow down the migration/invasion speed of cancer cells and suppress metastasis. Since nuclear stiffness of the cell largely decreases cell migration, our hypothesis is that targeting AuNPs to the cell nucleus region could enhance nuclear stiffnes...

Undoubtedly, Dr. Ahmed Zewail, who passed away on August 2, 2016, had a strong, positive impact on science in the Middle East and in the West. I knew Zewail as one of his mentors and close friends. Zewail wanted to come from Egypt (Alexandria University) to get his PhD in my group at the University of California, Los Angeles (UCLA). Unfortunately,...

We present a novel three-dimensional chiral metamaterial design for chiroptical spectroscopy. Utilizing the chiral light-matter interaction between the designed metamaterial and molecule that is chiral in the same wavelength range, we demonstrate chiroptical sensing at the molecular level.

Gold nanorods (GNRs) are now under extensive investigation for biomedical applications. The in vivo genotoxic profile GNRs are not elucidated yet, therefore we investigated it in comparison with one of the most effective chemotherapeutic agents, cyclophosphamide (CP), in a mice model. PEGylated-GNRs (50 nm) were injected to Balb/C mice triple times...

As a minimally invasive therapeutic strategy, gold nanorod (AuNRs) -based plasmonic photothermal therapy (PPT) has shown significant promise for the selective ablation of cancer cells. However, the heat stress experienced by cells during the PPT treatment produces significant amounts of reactive oxygen species (ROS), which could harm healthy, untre...

Significance In this work, we investigate the role of defects on the electronic and photocatalytic properties of In 2 O 3 - x (OH) y nanoparticles that have been shown to effectively reduce CO 2 to CO via the reverse water–gas shift reaction under light. To understand how such defects affect photogenerated electrons and holes in these materials, we...

We report on the optical properties of silver nanodisk (Ag ND) Langmuir Blodgett monolayers that were transferred to substrates in different coupling regimes. Ag ND monolayers deposited in the liquid expanded-gaseous (Le-G) phase demonstrated individual plasmon resonance behavior while monolayers deposited in the liquid condensed-liquid expanded (L...

We report novel multi-responsive plasmonic core-shell anisotropic nanostructures composed of gold nanorod (AuNR) and responsive polyaniline (PANI) shells with plasmonic mode appearance reversibly modulated through orthogonal stimuli; electrical potential and pH change in contrast to traditional systems with single-stimulus tunability. In this syste...

Modulation of PPTT toward inducing cancer cell apoptosis. Notes: (A–D) Shows the MCF-7 cell apoptosis/necrosis states of the in vitro experiment. (A) Cells without AuNRs. (B) Cells incubated with AuNRs (no laser). (C) Cells incubated with AuNRs and 2 minutes laser irradiation. (D) Cells incubated with AuNRs and 5 minutes laser irradiation. (E) Lase...

Photographs complete for Case 7 (Tumor 6: caudo-inguinal opened tumor and Tumor 10: anterior thoracic tumors) showing tumor regression after each treatment. Note: (A) Before treatment, (B) 2 weeks after the third treatment, and (C) 1 year after the third treatment.

Histopathology images (stained with H&E [×400]) for Case 3. Notes: (A) Well-differentiated tubular adenocarcinoma before treatment. Carcinoma arranged in tubular pattern. Mass characterized by an intra-acinar deeply basophilic secretion and corpora amylecea. Connective tissue stroma infiltrated with mononuclear cells (tumor Grade III). (B) 2 weeks...

Case 2 before treatment. Notes: (A) The X-ray shows there is no metastasis in the internal organs. (B) Ultrasound shows the tumor location, shape, and dimensions.

Photographs for case 3 (Tumor 2: left caudothoracic mammary gland and Tumor 13: right abdominal mammary gland) showing the tumor regression after each treatment. Note: (A) Before treatment, (B) 2 weeks after the third treatment, and (C) 1 year after the third treatment.

Photographs for Case 2 (Tumor 4: left caudothoracic mammary gland and Tumor 9: right abdominal mammary gland) showing the tumor regression 2 weeks after first treatment (A) and 1 year after the third treatment (B).

X-ray lateral exposure for Case 3 after treatment. Note: (A) 2 weeks after third treatment, (B) 1 year after third treatment, showing there is no metastasis.

TB remains a challenging disease to control worldwide. Nanoparticles have been used as drug carriers to deliver high concentrations of antibiotics directly to the site of infection, reducing the duration of treatment along with any side effects of off-target toxicities after systemic exposure to the antibiotics. Herein we have developed a drug deli...

Plasmonic photothermal therapy (PPTT) is a cancer therapy in which gold nanorods are injected at the site of a tumor before near-infrared light is transiently applied to the tumor causing localized cell death. Previously, PPTT studies have been carried out on xenograft mice models. Herein, we report a study showing the feasibility of PPTT as applie...

Nanomedicine represents an emerging and innovative field, which can potentially improve the way we diagnose, treat, and prevent cancer. At the nanoscale, some elements demonstrate unique properties that are not observed in their bulk entity, such as paramagnetism and surface plasmon resonance. Engineering nanostructures with precise control of size...

Proceedings: AACR 107th Annual Meeting 2016; April 16-20, 2016; New Orleans, LA Plasmonic gold nanorods (AuNRs) are very promising for biomedical applications because of their strongly enhanced radiation (e.g. absorption and scattering) and non-radioactive photothermal properties due to surface plasmon resonance. In plasmonic photothermal therapy...

Platinum-silver nanocage catalysts with a precisely defined shape and composition were synthesized using the galvanic replacement reaction (GRR) and utilized as electrocatalysts for the oxygen reduction reaction (ORR). The electrocatalytic activity of these platinum-silver nanocages was determined as a function of platinum content. The specific cur...

Plasmonic photothermal therapy (PPTT) is a promising cancer treatment where plasmonic nanoparticles are used to convert near infrared light to localized heat to cause cell death, mainly via apoptosis and necrosis. Modulating PPTT to induce cell apoptosis is more favorable than necrosis. Herein, we used a mild treatment condition using gold nanorods...

In operando resonance Raman spectroscopy suggests quantitative correlation between phonon band properties and the amount of charge storage of high-energy density NiO2H x battery/pseudocapacitive material. Comparing the spectroscopic evolution using different electrolytes reveals the contributions of breaking/formation of O-H bonds and insertion/ex...

In this paper, we presented a detailed theoretical investigation on the effects of changing the refractive index of the substrate and the interparticle separation distance on the electromagnetic field distribution around the face-to-face (FF) and the edge-to-edge (EE) oriented silver nanocube (Ag NC) dimers. We found that the contribution of the sc...

We present a rational approach to fabricating plasmonically active hybrid polymer-metal nanomaterials with electrochemical tunability of the localized surface plasmon resonances (LSPRs) of noble metal nanostructures embedded in an electroactive polymer matrix. The key requirement for being able to significantly modulate the LSPR band position is a...

In the close vicinity of a chiral nanostructure, the circular dichroism of a biomolecule could be greatly enhanced, due to the interaction with the local superchiral fields. Modest enhancement of optical activity using a planar metamaterial, with some chiral properties, and achiral nanoparticles has been previously reported. A more substantial chir...

We demonstrate the electrically controlled and reversible plasmonic signature of hybrid polymer–metal nanostructures composed of core/shell nanostructures: gold nanocubes (AuNCs) coated with electrochromic polyaniline (PANI) shells. A reversible tuning of the localized surface plasmon resonance (LSPR) peak of the AuNC core was obtained by applying...

We present, herein, visible-light water splitting using earth-abundant zirconium-based nanostructured photoanodes. ZrO2/ZrON core/shell arrays were fabricated via the atomic layer deposition (ALD) of various ZrN layers on anodically synthesized hexagonal ZrO2 nanotubes. Compositional analysis of the composite photoanodes showed the transformation o...

I believe that everyone gets a few good breaks in his or her life. The lucky ones are those who recognize them and change their lives accordingly. Like most of us here tonight, I did. From the day I was born in a small village by the Nile Delta in Egypt until today, I have recognized a few good breaks that helped me to be able to stand in front of...

It is important to understand the molecular mechanisms underlying oxygen toxicity, which contributes to multiple human disorders. The archetype model of oxygen toxicity is neonatal lung injury induced by hyperoxia exposure. Here, we utilized plasmonically-enhanced Raman spectroscopy (PERS) in combination with fluorescence and proteomic analysis to...