First principle simulation of coated hydroxychloroquine on Ag, Au and Pt nanoparticles

Fluorometric and colorimetric platforms for rapid and sensitive hydroxychloroquine detection in aqueous samples

The detection of pharmaceuticals has been an active area of research with numerous application areas ranging from therapeutic and environmental monitoring to pharmaceutical manufacturing and diagnostics. And, the emergence of COVID-19 pandemic has increased the demand for detection of certain active pharmaceutical ingredients such as Hydroxychloroquine (HCQ) mainly due to their increased manufacturing and usage. In this study, we present two optical, fluorometric and colorimetric, detection platforms for the rapid and sensitive detection of HCQ. These platforms take advantage of the interactions between the highly fluorescent dye Thioflavin T (ThT) and Tel24 G-quadruplex (G4) DNA structure, as well as the salt-induced aggregation behavior of negatively charged citrate-capped silver nanoparticles (Cit-AgNPs) in the presence of HCQ. In the fluorometric method, the addition of HCQ led to a significant and rapid decrease in the fluorescence signal of the ThT + Tel24 probe. In the colorimetric method, HCQ induced the aggregation of Cit-AgNPs in the presence of NaCl, resulting in a noticeable color change from yellowish-gray to colorless. Under the optimized conditions, the colorimetric platform exhibited a linear range of 18.0-240.0 nM and a detection limit of 9.2 nM, while the fluorometric platform showed a linear range of 0.24-5.17 μM and a detection limit of 120 nM. The selectivity of the proposed optical methods towards the target analyte was demonstrated by evaluating the response to other structurally similar small molecules. Finally, the practical applicability of both detection systems was confirmed by analyzing HCQ-spiked human urine samples that yielded average recoveries ranging from 75.4 to 110.2 % for the fluorometric platform and 86.9-98.2 % for the colorimetric platform. These results indicate the potential of the developed methods for HCQ detection in complex matrices.

Localized surface plasmon resonance sensing of Trenbolone acetate dopant using silver nanoparticles

In this work, localized surface plasmon resonance (LSPR) sensing as applicable in the detection of Trenbolone acetate dopant is demonstrated. We show that the LSPR of the Trenbolone acetate/silver nanoparticle (Tren Ac/AgNPs) complex is sensitive to changes in the adsorbent concentration. The results show an average redshift of + 18 nm in the LSPR peak with variations in intensity and broadening behavior of the LSPR band of the Tren Ac/AgNPs complex. AgNPs were synthesized using laser ablation in liquid (LAL) technique with water as the solvent. UV-Vis spectroscopy was used for absorbance measurements and particle size and morphology were monitored using scanning electron microscopy (SEM). The aggregation behavior of the Tren Ac/AgNPs complex was monitored using energy-dispersive X-ray spectroscopy (EDS). Molecular Electrostatic Potential (MEP) and the HOMO-LUMO orbitals of the optimized Trenbolone acetate structure were obtained using Density Function Theory (DFT). The molecule was optimized at the B3LYP level of theory using the 6-311 basis set carried out using the Gaussian 09 software package. The results showed that O2- is Trenbolone acetate's active site that would interact with Ag+ to form a complex that would influence the plasmon behavior. The results presented in this work demonstrate the feasibility of LSPR for anabolic androgenic steroid detection.

Molecular Simulation Study of Surface-Enhanced Raman Scattering of Liquid Water

We developed in our previous study [J. Chem. Phys., 2021, 155, 174118, J. Phys. Chem. A, 2022, 126, 4762] a classical electronic and molecular dynamics simulation method to describe the optical response of metal material in solution based on an atomistic model by incorporating the classical equation of motion for free electrons under an applied electric field. To show further usefulness of the method, in the present study, we apply it to surface-enhanced Raman scattering of liquid water to examine the signal enhancement of the solution system caused by plasmon resonance effects of a silver nanoparticle.

Ionome mapping and amino acid metabolome profiling of Phaseolus vulgaris L. seeds imbibed with computationally informed phytoengineered copper sulphide nanoparticles

This study reports the effects of a computationally informed and avocado-seed mediated Phyto engineered CuS nanoparticles as fertilizing agent on the ionome and amino acid metabolome of Pinto bean seeds using both bench top and ion beam analytical techniques. Physico-chemical analysis of the Phyto engineered nanoparticles with scanning-electron microscopy, transmission electron microscopy, X-ray diffraction, and Fourier Transform Infrared Spectroscopy confirmed the presence of CuS nanoparticles. Molecular dynamics simulations to investigate the interaction of some active phytocompounds in avocado seeds that act as reducing agents with the nano-digenite further showed that 4-hydroxybenzoic acid had a higher affinity for interacting with the nanoparticle's surface than other active compounds. Seeds treated with the digenite nanoparticles exhibited a unique ionome distribution pattern as determined with external beam proton-induced X-ray emission, with hotspots of Cu and S appearing in the hilum and micropyle area that indicated a possible uptake mechanism via the seed coat. The nano-digenite also triggered a plant stress response by slightly altering seed amino acid metabolism. Ultimately, the nano-digenite may have important implications as a seed protective or nutritive agent as advised by its unique distribution pattern and effect on amino acid metabolism.

Theoretical study of chemical reactivity descriptors of some repurposed drugs for COVID-19

This study focuses on computational studies of chemical reactivity descriptors of some proposed drugs for COVID-19. Density functional theory calculations were used to optimize the structure and investigate the frontier orbitals and the chemical reactivity descriptors of these drugs. The frontier orbitals, which include both the highest occupied molecular orbital (HOMO) and the lowest unoccupied molecular orbital (LUMO), play an essential role in molecular interactions and chemical reactivity of molecule. Polarizability, which determines the response of the susceptibility of a molecule to an approaching charge, is higher in the more complex drugs such as Hydroxychloroquine, Remdesivir, and Ivermectin compare to the smaller drugs. The HOMO and LUMO orbital energies were calculated to obtain the energy gap of the studied drugs, which is in the following order: Favipiravir < Hydroxychloroquine, Remdesivir < Ivermectin < Artesunate < Artemether < Artemisinin. Generally, molecules with a larger energy gap have lower chemical reactivity and higher kinetic stability.

Graphical abstract

Advanced Plasmonic Nanoparticle-Based Techniques for the Prevention, Detection, and Treatment of Current COVID-19

Coronavirus is an ongoing global pandemic caused by severe acute respiratory syndrome coronavirus 2. Coronavirus disease 2019 known as COVID-19 is the worst pandemic since World War II. The outbreak of COVID-19 had a significant repercussion on the health, economy, politics, and environment, making coronavirus-related issues more complicated and becoming one of the most challenging pandemics of the last century with deadly outcomes and a high rate of the reproduction number. There are thousands of different types - or variants - of COVID circulating across the world. Viruses mutate all the time; it emphasizes the critical need for the designing of efficient vaccines to prevent virus infection, early and fast diagnosis, and effective antiviral and protective therapeutics. In this regard, the use of nanotechnology offers new opportunities for the development of novel strategies in terms of prevention, diagnosis, and treatment of COVID-19. This review presents an outline of the platforms developed using plasmonic nanoparticles in the detection, treatment, and prevention of SARS-CoV-2. We select the best strategies in each of these approaches. The properties of metallic plasmon NPs and their relevance in the development of novel point-of-care diagnosis approaches for COVID-19 are highlighted. Also, we discuss the current challenges and the future perspectives looking towards the clinical translation and the commercial aspects of nanotechnology and plasmonic NP-based diagnostic tools and therapy to fight COVID-19 pandemic. The article could be of significance for researchers dedicated to developing suitable plasmonic detection tools and therapy approaches for COVID-19 viruses and future pandemics.

A systemic review on liquid crystals, nanoformulations and its application for detection and treatment of SARS - CoV- 2 (COVID - 19)

The COVID-19 is a pandemic caused by the SARS-CoV-2 virus, has instigated major health problems and prompted WHO to proclaim a worldwide medical emergency. The knowledge of SARS-CoV-2 fundamental structure, aetiology, its entrance mechanism, membrane hijacking and immune response against the virus, are important parameters to develop effective vaccines and medicines. Liquid crystals integrated nano-techniques and various nanoformulations were applied to tackle the severity of the virus. It was reported that nanoformulations have helped to enhance the effectiveness of presently accessible antiviral medicines or to elicit a fast immunological response against COVID-19 virus. Applications of liquid crystals, nanostructures, nanoformulations and nanotechnology in diagnosis, prevention, treatment and tailored vaccine administration against COVID-19 which will help in establishing the framework for a successful pandemic combat are reviewed. This review also focuses on limitations associated with liquid crystal-nanotechnology based systems and suggests the possible ways to address these limitations. Also, topical advancements in the ground of liquid crystals and nanostructures established diagnostics (nanosensor/biosensor) are discussed in detail.

Computational Analyses of Plasmonics of a Silver Nanoparticle in a Vacuum and in a Water Solution by Classical Electronic and Molecular Dynamics Simulations

We present basic optical responses of a silver nanoparticle (Ag309) in a vacuum and a water solution obtained by classical electronic and molecular dynamics (CEMD) calculations, where the CEMD is our previously developed force-field based molecular dynamics simulation method that incorporates the classical equation of motion for free electrons in metal and an interaction with the applied oscillating electric field (Yamada, A. J. Chem. Phys. 2021, 155, 174118)). The present work is the follow-up of the previous study. Calculated absorption spectra in the visible region with various conditions are reported together with parameter determination for realistic analyses as well as the verification of the method. Time-domain optical responses of Ag309 in water solvent are as well analyzed in terms of the plasmon resonance excitation under a subpicosecond light pulse and its thermal relaxation.

Metal and metal oxide-based antiviral nanoparticles: Properties, mechanisms of action, and applications

Certain types of metal-based nanoparticles are effective antiviral agents when used in their original form ("bare") or after their surfaces have been functionalized ("modified"), including those comprised of metals (e.g., silver) and metal oxides (e.g., zinc oxide, titanium dioxide, or iron dioxide). These nanoparticles can be prepared with different sizes, morphologies, surface chemistries, and charges, which leads to different antiviral activities. They can be used as aqueous dispersions or incorporated into composite materials, such as coatings or packaging materials. In this review, we provide an overview of the design, preparation, and characterization of metal-based nanoparticles. We then discuss their potential mechanisms of action against various kinds of viruses. Finally, the applications of some of the most common metal and metal oxide nanoparticles are discussed, including those fabricated from silver, zinc oxide, iron oxide, and titanium dioxide. In general, the major antiviral mechanisms of metal and metal oxide nanoparticles have been observed to be 1) attachment of nanoparticles to surface moieties of viral particles like spike glycoproteins, that disrupt viral attachment and uncoating in host cells; 2) generation of reactive oxygen species (ROS) that denature viral macromolecules such as nucleic acids, capsid proteins, and/or lipid envelopes; and 3) inactivation of viral glycoproteins by the disruption of the disulfide bonds of viral proteins. Several physicochemical properties of metal and metal oxide nanoparticles including size, shape, zeta potential, stability in physiological conditions, surface modification, and porosity can all impact the antiviral efficacy of the nanoparticles.

Computational Modeling of the Interaction of Silver Clusters with Carbohydrates

Silver nanoparticles are recognized for their numerous physical, biological, and pharmaceutical applications. In the present study, the interaction of silver clusters with monosaccharide molecules is examined to identify which molecule works better as a reducing agent in the application of a green synthesis approach. Geometry optimization of clusters containing one, three, and five silver atoms is performed along with the optimization of α-d-glucose, α-d-ribose, d-erythrose, and glyceraldehyde using density functional theory. Optimized geometries allow identifying the interaction formed in the silver cluster and monosaccharide complexes. An electron localization function analysis is performed to further analyze the interaction found and explain the reduction process in the formation of silver nanoparticles. The overall results indicate that glyceraldehyde presents the best characteristics to serve as the most efficient reducing agent.

Potential metal-related strategies for prevention and treatment of COVID-19

ABSTRACT

The coronavirus disease 2019 (COVID-19) caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has posed severe threats to human health, public safety, and the global economy. Metal nutrient elements can directly or indirectly take part in human immune responses, and metal-related drugs have served as antiviral drugs and/or enzyme inhibitors for many years, providing potential solutions to the prevention and treatment of COVID-19. Metal-based drugs are currently under a variety of chemical structures and exhibit wide-range bioactivities, demonstrating irreplaceable advantages in pharmacology. This review is an intention to summarize recent progress in the prevention and treatment strategies against COVID-19 from the perspective of metal pharmacology. The current and potential utilization of metal-based drugs is briefly introduced. Specifically, metallohydrogels that have been shown to present superior antiviral activities are stressed in the paper as potential drugs for the treatment of COVID-19.

Classical electronic and molecular dynamics simulation for optical response of metal system

An extended molecular dynamics simulation that incorporates classical free electron dynamics in the framework of the force-field model has been developed to enable us to describe the optical response of metal materials under the visible light electric field. In the simulation, dynamical atomic point charges follow equations of motion of classical free electrons that include Coulomb interactions with the oscillating field and surrounding atomic sites and collision effects from nearby electrons and ions. This scheme allows us to simulate an interacting system of metals with molecules using an ordinary polarizable force-field and preserves energy conservation in the case without applying an external electric field. As the first applications, we show that the presented simulation accurately reproduces (i) the classical image potential in a metal-charge interaction system and (ii) the dielectric function of bulk metal. We also demonstrate (iii) calculations of absorption spectra of metal nano-particles with and without a water solvent at room temperature, showing reasonable red-shift by the solvent effect, and (iv) plasmon resonant excitation of the metal nano-particle in solution under the visible light pulse and succeeding energy relaxation of the absorbed light energy from electrons to atoms on the metal and to the water solvent. Our attempt thus opens the possibility to expand the force-field based molecular dynamics simulation to an alternative tool for optical-related fields.

Could Nanotechnology Help to End the Fight Against COVID-19? Review of Current Findings, Challenges and Future Perspectives

A serious viral infectious disease was introduced to the globe by the end of 2019 that was seen primarily from China, but spread worldwide in a few months to be a pandemic. Since then, accurate prevention, early detection, and effective treatment strategies are not yet outlined. There is no approved drug to counter its worldwide transmission. However, integration of nanostructured delivery systems with the current management strategies has promised a pronounced opportunity to tackle the pandemic. This review addressed the various promising nanotechnology-based approaches for the diagnosis, prevention, and treatment of the pandemic. The pharmaceutical, pharmacoeconomic, and regulatory aspects of these systems with currently achieved or predicted beneficial outcomes, challenges, and future perspectives are also highlighted.

An overview of the use of biomaterials, nanotechnology, and stem cells for detection and treatment of COVID-19: towards a framework to address future global pandemics

A novel SARS-like coronavirus (severe acute respiratory syndrome-related coronavirus-2, SARS-CoV-2) outbreak has recently become a worldwide pandemic. Researchers from various disciplinary backgrounds (social to natural science, health and medicine, etc.) have studied different aspects of the pandemic. The current situation has revealed how the ongoing development of nanotechnology and nanomedicine can accelerate the fight against the novel viruses. A comprehensive solution to this and future pandemic outbreaks includes preventing the spread of the virus through anti-viral personal protective equipment (PPE) and anti-viral surfaces, plus efforts to encourage behavior to minimize risks. Studies of previously introduced anti-viral biomaterials and their optimization to fight against SARS-CoV-2 is the foundation of most of the recent progress. The identification of non-symptomatic patients and symptomatic patients is vital. Reviewing published research highlights the pivotal roles of nanotechnology and biomaterials in the development and efficiency of detection techniques, e.g., by applying nanotechnology and nanomedicine as part of the road map in the treatment of coronavirus disease 2019 (COVID-19) patients. In this review, we discuss efforts to deploy nanotechnology, biomaterials, and stem cells in each step of the fight against SARS-CoV-2, which may provide a framework for future efforts in combating global pandemics.