BACKGROUND:Overexpression of cyclooxygenase-2 (COX-2) has been associated with hepatocellular carcinoma (HCC). Selective inhibition of COX-2 can come forward as improved and targeted therapeutic strategy. METHODS:We hereby determine selective inhibition efficiency of COX-2 enzyme in HepG2 cells through laser-assisted oligonucleotides release from remote optical nano-switches (LORONS) with spatial and temporal control. Gold nanorods (GNRs) were decorated with fluorescein labeled single and double strand RNA interfering oligos through methoxy PEG thiol linkages. Upon uptake by HepG2 cell, conjugated GNRs were exposed to continuous NIR laser irradiation near the resonance wavelength of GNRs (808 nm) for controlled release of oligos. RESULTS:COX-2 protein expression was reduced by 93% after NIR laser exposure compared to control sample after 48 h (p < 0.05). Significant reduction in prostaglandin E2(PGE2) levels after LORONS treatment was also observed. Gene silencing efficacy using GNRs conjugated oligos without laser exposure was recorded 38%. CONCLUSION:We hereby conclude LORONS as a useful therapeutic strategy for localized gene silencing by remote optical excitation at desired intracellular location.

Arginine (R)-glycine (G)-aspartate (D) (RGD)-containing oligopeptides are known to be very effective in increasing the biocompatibility and bioconnectivity of gold nanorods (AuNRs), where the conformation of the RGD peptide plays a critical role. In this work, Fourier-transform infrared (FTIR) and circular dichroism (CD) spectroscopies are used to characterize the secondary structure of a typical RGD peptide, namely, (RGD)4PGC, in its solvated state and the AuNRs' surface-bound state (AuNRs@RGD) at neutral pH. It is shown that such a 15-mer RGD contains a beta-turn on its C-terminus (residue DPGC), a short beta-strand in the middle, and a random coil on its N-terminus (the RGD replica region). Upon its binding to AuNRs, a small portion of the beta-strand is converted into a random coil, thus having a longer segment of random coil than its free form. Moreover, the steady-state conformational change is accompanied by a significant change in ultrafast structural dynamics, as revealed by time-resolved 2D IR spectroscopy. In particular, the increased rigidity in both beta-strand and beta-turn, including the side chain of arginine residues, is found in AuNRs@RGD. These steady-state and dynamic features both suggest that once attached to the surface of Au nanorods, the RGD peptide could exhibit an increased bio-binding stability due to the overall increased rigidity of the peptide, including the backbone and alternatively located and positively (R) and negatively (D) charged side chains at the N-terminus. Our work provides an insight into the structural dynamics of the working mechanism of the RGD peptides.

Combined chemo-photothermal therapy (CT-PTT) based on gold nanorods (AuNRs) loaded with chemotherapies has been recently introduced as a promising anticancer therapy with relatively lower side effects and higher efficacy over individual therapeutic approaches. We fabricated ss-cyclodextrin-based nanosponges encapsulating PEGylated gold nanorods and doxorubicin (DOX), AuNR-S-PEG.ss-CD NS-DOX, comprehensively characterized it using TEM, SEM, FE-SEM, FITR, and DLS and then evaluated it for CT-PTT versus the respective photothermal, AuNR-S-PEG.ss-CD NS, and chemotherapy DOX. The synthesized AuNR-S-PEG.ss-CD NS nanocomposite exhibited high photothermal conversion efficiency and high drug loading capacity based on the porous structure of the nanosponges. The drug-loaded nanocomposites, AuNR-S-PEG.ss-CD NS-DOX, showed pH/NIR dual-responsive drug release behaviors, good biocompatibility, and efficient uptake into A549 lung cancer cells, as well as higher efficiency in killing cancer cells than single chemo- or photothermal therapy. Overall, the findings of this study demonstrate AuNR-S-PEG.ss-CD NS-DOX nanocomposites as a promising candidate for combined chemo-photothermal therapy of lung cancer.

The shape transition from spherical vibrator U(5) to γ -unstable deformed rotor O(6) in even-even Ru, Pd, and Xe isotopic chains are studied in framework of sd interacting boson model (IBM1) using the coherent state formalism to obtain the potential energy surfaces (PES’s). The location of critical points in the transition are identified by analysis the PES’s in terms of the deformation parameter β and by using the catastrophe theory in terms of the two essential parameters (r_1, r_2) . By using the most general IBM1 Hamiltonian in Casimir form with neglecting the U(5) and SU(3) quadratic Casimir operators and introducing only one control parameter the PES leads to the same energy surface as the Q-consistent IBM Hamiltonian at γ =0 . For the studied isotopic chains, the χ ^2 -test is used to perform the fitting between the experimental and the corresponding calculated IBM for some selected energy levels and electric quadrupole transition probabilities B( E 2) values using a simulated search program. A good agreement is produced for both energies and B( E 2) transition rates. The present model calculations suggest that ^100 Ru, ^102 Pd and ^130 Xe nuclei are good candidates for the E(5) critical point symmetry.

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-beta-CD-DOX nanocomposite, for intracellular delivery were designed to enhance therapeutic efficacy and improve toxicity of gold nanorods. The UV-vis absorption spectra of the AuNRs@S-beta-CD nanocomposite showed strong absorption in the NIR region (biological window), making it a promising candidate for both photothermal therapy and chemotherapy. With such a combined chemo-photothermal effect, the viability of AS49 lung cancer cells in vitro is anticipated to be significantly reduced making it a promising biomedical material for cancer treatment. The results show good photothermal efficiency of gold nanorods, high loading capacity for DOX, and biocompatibility of the AuNRs@S-beta-CD-DOX nanocomposite.

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 therapy (PTT) mechanism is combined with a chemotherapy (chemo) mechanism using ionic liquid chemistry to develop a combination drug to deliver multiple cytotoxic mechanisms simultaneously. Nanodrugs were developed from an ionic material-based chemo-PTT combination drug by using a simple reprecipitation method. Detailed examination of the photophysical properties (absorption, fluorescence emission, quantum yield, radiative and non-radiative rate) of the INMs revealed significant spectral changes which are directly related to their therapeutic effect. The reactive oxygen species quantum yield and the light to heat conversion efficiency of the photothermal agents were shown to be enhanced in combination nanomedicines as compared to their respective parent compounds. The ionic nanodrugs exhibited an improved dark and light cytotoxicity in vitro as compared to either the chemotherapeutic or photothermal parent compounds individually, due to a synergistic effect of the combined therapies, improved photophysical properties and their nanoparticles' morphology that enhanced the cellular uptake of the drugs. This study presents a general framework for the development of carrier-free dual-mechanism nanotherapeutics.

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 consumption, is still elusive. Here, we demonstrate an in situ electrically driven tunable metasurface by harnessing the full potential of a PCM alloy, Ge 2 Sb 2 Te 5 (GST), to realize non-volatile, reversible, multilevel, fast, and remarkable optical modulation in the near-infrared spectral range. Such a reprogrammable platform presents a record eleven-fold change in the reflectance (absolute reflectance contrast reaching 80%), unprecedented quasi-continuous spectral tuning over 250 nm, and switching speed that can potentially reach a few kHz. Our scalable heterostructure architecture capitalizes on the integration of a robust resistive microheater decoupled from an optically smart metasurface enabling good modal overlap with an ultrathin layer of the largest index contrast PCM to sustain high scattering efficiency even after several reversible phase transitions. We further experimentally demonstrate an electrically reconfigurable phase-change gradient metasurface capable of steering an incident light beam into different diffraction orders. This work represents a critical advance towards the development of fully integrable dynamic metasurfaces and their potential for beamforming applications.

Ammonia holds great promise as a carbon-neutral liquid fuel for storing intermittent renewable energy sources and power generation due to its high energy density and hydrogen content. Photo-Electrochemical Ammonia Synthesis: Nanocatalyst Discovery, Reactor Design, and Advanced Spectroscopy covers the synthesis of novel hybrid plasmonic nanomaterials and their application in photo-electrochemical systems to convert low energy molecules to high value-added molecules and looks specifically at photo-electrochemical nitrogen reduction reaction (NRR) for ammonia synthesis as an attractive alternative to the long-lasting thermochemical process. Provides an integrated scientific framework, combining materials chemistry, photo-electrochemistry, and spectroscopy to overcome the challenges associated with renewable energy storage and transport Reviews materials chemistry for the synthesis of a range of heterogeneous (photo) electrocatalysts including plasmonic and hybrid plasmonic-semiconductor nanostructures for selective and efficient conversion of N2 to NH3 Covers novel reactor design to study the redox processes in the photo-electrochemical energy conversion system and to benchmark nanocatalysts’ selectivity and activity toward NRR Discusses the use of advanced spectroscopic techniques to probe the reaction mechanism for ammonia synthesis Offers techno-economic analysis and presents performance targets for the scale-up and commercialization of electrochemical ammonia synthesis This book is of value to researchers, advanced students, and industry professionals working in sustainable energy storage and conversion across the disciplines of Chemical Engineering, Mechanical Engineering, Materials Science and Engineering, Environmental Engineering, and related areas.

Sajjad Abdollahramezani, Omid Hemmatyar, Mohammad Taghinejad, Hossein Taghinejad, Alex Krasnok, Ali A. Eftekhar, Christian Teichrib, Sanchit Deshmukh, Mostafa El-Sayed, Eric Pop, Matthias Wuttig, Andrea Alù, Wenshan Cai, and Ali Adibi1∗ School of Electrical and Computer Engineering, Georgia Institute of Technology, 778 Atlantic Drive NW, Atlanta, Georgia 30332-0250, United States Photonics Initiative, Advanced Science Research Center, City University of New York, New York, NY 10031, United States Department of Electrical Engineering, Department of Materials Science and Engineering, Precourt Institute for Energy, Stanford University, Stanford, California 94305, United States Laser Dynamics Laboratory, School of Chemistry and Biochemistry, Georgia Institute of Technology, Atlanta, Georgia, 30332-0400, United States George W. Woodruff School of Mechanical Engineering, Georgia Institute of Technology, Atlanta, Georgia, 30332-0405, United States Physikalisches Institut IA, RWTH Aachen, Sommerfeldstrasse 14, 52074 Aachen, Germany Physics Program, Graduate Center, City University of New York, New York, NY 10016, United States and School of Materials Science and Engineering, Georgia Institute of Technology, 801 Ferst Drive NW, Atlanta, Georgia 30332-0295, United States (Dated: April 27, 2021)

As renewable energy sources are either intermittent in nature or remote in location, developing cost-effective, sustainable, modular systems and technologies to store and transport renewables at an industrial scale is imperative. Storing cheap renewable electricity into chemical bonds (i.e., chemical energy storage) could be a transformative opportunity for reliable and resilient grid energy storage. This approach enables renewables to be stored and shipped similarly to fossil fuels. Currently, the chemical industry primarily consumes fossil feedstock as an energy source, which has been the standard for over a century. A paradigm shift is required to move toward a more sustainable route for chemical synthesis by electrifying and decarbonizing the modern chemical industry. As renewable electricity costs decrease, (photo)electrosynthesis is gaining interest for synthesizing high-value and high-energy fuels and molecules in a clean, sustainable, and decentralized manner.The nitrogen cycle is one of the Earth's most critical biogeochemical cycles since nitrogen is a vital element for all living organisms. Artificial nitrogen fixation via a (photo)electrochemical system powered by renewables provides an alternative route to resource- and carbon-intensive thermochemical processes. (Photo)electrochemical nitrogen fixation at a large scale necessitates the discovery of active, selective, and stable heterogeneous (photo)electrocatalysts. In addition, the use of advanced in situ and operando spectroscopic techniques is needed to pinpoint the underlying reaction mechanisms. The selectivity of nitrogen (N2) molecules on the catalyst surface and suppressing thermodynamically favorable side reactions (e.g., hydrogen evolution reaction) are the main bottlenecks in improving the rate of (photo)electrochemical nitrogen fixation in aqueous solutions. The rational design of electrode, electrolyte, and reactors is required to weaken the strong nitrogen-nitrogen triple bond (N≡N) at or near ambient conditions. This Account covers our group's recent advances in synthesizing shape-controlled hybrid plasmonic nanoparticles, including plasmonic-semiconductor and plasmonic-transition metal nanostructures with increased surface areas. The nanocatalysts' selectivity and activity toward nitrogen conversion are benchmarked in liquid- and gas-phase electrochemical systems. We leverage operando vibrational-type spectroscopy (i.e., surface-enhanced Raman spectroscopy (SERS)) to identify intermediate species relevant to nitrogen fixation at the electrode-electrolyte interface to gain mechanistic insights into reaction mechanisms, leading to the discovery of more efficient catalysts. Operando SERS revealed that the nitrogen reduction reaction (NRR) to ammonia on hybrid plasmonic-transition metal nanoparticle surfaces (e.g., Pd-Ag) occurs through an associative mechanism. In the NRR process, hydrazine (N2H4) is consumed as an intermediate species. A femtosecond pulsed laser is used to synthesize hybrid plasmonic photocatalysts with homogeneously distributed Pd atoms on a Au nanorod surface, resulting in enhanced optoelectronic and catalytic properties. The overarching goal is to develop modular photoelectrochemical systems for long-duration renewable energy storage. In the context of nitrogen fixation, we aim to propose strategies to manage the nitrogen cycle through the interconversion of N2 and active nitrogen-containing compounds (e.g., NH3, NOx), enabling a circular nitrogen economy with sustainable and positive social and economic outcomes. The versatile approaches presented in this Account can inform future opportunities in (photo)electrochemical energy conversion systems and solar fuel-based applications.

It is now well-accepted that nanoparticles (NPs) introduced into a biological environment will interact with the available proteins that deposit on their surface in a process known as protein corona (PC) formation which control NP interactions with cells and biological barriers. Several investigations have been conducted to understand the mechanisms and kinetics of PC formation. Among the model nanoprobes are gold (Au) NPs that possess unique optical and electromagnetic properties due to their surface plasmon resonance. These properties make Au NPs excellent probes for studying PC formation. In this Review, we describe techniques and approaches that a researcher interested in investigating PC on Au NPs may utilize in order to characterize the PC formation.

Despite recent advances in active metaoptics, wide dynamic range combined with high-speed reconfigurable solutions is still elusive. Phase-change materials (PCMs) offer a compelling platform for metasurface optical elements, owing to the large index contrast and fast yet stable phase transition properties. Here, we experimentally demonstrate an in situ electrically-driven reprogrammable metasurface by harnessing the unique properties of a phase-change chalcogenide alloy, Ge_2Sb_2Te_5 (GST), in order to realize fast, non-volatile, reversible, multilevel, and pronounced optical modulation in the near-infrared spectral range. Co-optimized through a multiphysics analysis, we integrate an efficient heterostructure resistive microheater that indirectly heats and transforms the embedded GST film without compromising the optical performance of the metasurface even after several reversible phase transitions. A hybrid plasmonic-PCM meta-switch with a record electrical modulation of the reflectance over eleven-fold (an absolute reflectance contrast reaching 80 tuning over 250 nm, and switching speed that can potentially reach a few kHz is presented. Our work represents a significant step towards the development of fully integrable dynamic metasurfaces and their potential for beamforming applications.

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 by incorporating the phase-change material Ge2Sb2Te5 (GST) into metal-dielectric meta-atoms for active and nonvolatile tuning of properties of light. We systematically design a reduced-dimension meta-atom, which selectively controls the hybrid plasmonic-photonic resonances of the metasurface via the dynamic change of optical constants of GST without compromising the scattering efficiency. As a proof-of-concept, we experimentally demonstrate two tunable metasurfaces that control the amplitude (with relative modulation depth as high as ≈80%) or phase (with tunability >230°) of incident light promising for high-contrast optical switching and efficient anomalous to specular beam deflection, respectively. Our findings further substantiate dynamic hybrid metasurfaces as compelling candidates for next-generation reprogrammable meta-optics.

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 that can selectively eradicate the respiratory virus load. We propose a novel COVID-19 management approach that is efficient in eliminating the virus load from the airways and protecting the lungs from the fatal effects of the virus. This approach relies on targeting the virus using ACE-2-functionalized gold nanorods (AuNRs) followed by irradiation with near-infrared (NIR) light for the selective eradication of SARS-CoV-2 without off-target effects, i.e., targeted plasmonic photothermal therapy. Using discrete dipole approximation (DDA), we quantitatively determined the efficiency of AuNRs (31 nm × 8 nm) in absorbing NIR when present at different orientations relative to one another on the surface of the virus. The safety and the local administration of AuNRs using a well-tolerated flexible bronchoscopy technique, commonly used for hospitalized COVID-19 patients, ensure feasibility and clinical translation. While requiring further research, we anticipate this approach to result in a first-line treatment for hospitalized COVID-19 patients that are experiencing severe respiratory conditions or belong to a high-risk population, e.g., seniors and diabetic patients.