Mode of antiviral action of silver nanoparticles against HIV-1

Tackling COVID-19 Using Antiviral Nanocoating's-Recent Progress and Future Challenges

In the current situation of the global coronavirus disease 2019 (COVID-19) pandemic, there is a worldwide demand for the protection of regular handling surfaces from viral transmission to restrict the spread of COVID-19 infection. To tackle this challenge, researchers and scientists are continuously working on novel antiviral nanocoatings to make various substrates capable of arresting the spread of such pathogens. These nanocoatings systems include metal/metal oxide nanoparticles, electrospun antiviral polymer nanofibers, antiviral polymer nanoparticles, graphene family nanomaterials, and etched nanostructures. The antiviral mechanism of these systems involves depletion of the spike glycoprotein that anchors to surfaces by the nanocoating and makes the spike glycoprotein and viral nucleotides inactive; however, the nature of the interaction between the spike proteins and virus depends on the type of nanostructure and a surface charge over the coating surface. In this article, the current scenario of COVID-19 and how it can be tackled using antiviral nanocoatings from the further transmission of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), along with their different mode of action, are discussed. Additionally, it is also highlighted different types of nanocoatings developed for various substrates to encounter transmission of SARS-CoV-2, future research areas along with the current challenges related to it, and how these challenges can be resolved.

Comparative Analysis of the Interaction of Silver Nanoparticles with Hexokinase from Trypanosoma brucei and Humans

Background

Regardless of the efforts to ease cases of human African trypanosomiasis (HAT), an increased number of cases get reported annually. This is because of drug resistant Trypanosoma brucei (Tb), the causative agent of the illness. This has renewed the need for creative methods to find new anti-trypanosomal drugs. The blood stream form (BSF) of the parasite depends exclusively on the glycolytic pathway for energy production while it is in the human host. Interruptions in this pathway efficiently kills the parasite. Trypanosoma brucei hexokinase (TbHK) is the first enzyme in glycolysis, and any effectors or inhibitors of TbHK would have potential as anti-trypanosomal agents.

Methods

TbHK and human glucokinase (hGCK) were over-expressed with a 6 histidine-tag in E. coli BL21(DE3) cells having the pRARE2 plasmid.

Results

TbHK had thermal and pH stability between 30°C and 55°C and 7.5 and 8.5, respectively, while hGCK exhibited thermal and pH stability between 30°C and 40°C and 7.0 and 8.0, respectively. Kinetically, TbHK had a K_m of 39.3 µM, V_max of 0.066 µmol.min^-1.mL^-1, k_cat of 2.05 min^-1 and k_cat/K_m of 0.0526 min^-1.µmol^-1. hGCK exhibited a K_m of 4.5 µM, V_max of 0.032 µnmol.min^-1.mL^-1, k_cat of 11.25 min^-1, and k_cat/K_m of 2.5 min^-1.µmol^-1. Interaction kinetic studies of silver nanoparticles (AgNPs) (0.1 µM) of average size of 6 nm with TbHK and hGCK were conducted. AgNPs selectively inhibited TbHK over hGCK. TbHK showed a non-competitive inhibition with a 50% and 28% decrease in V_max, and k_cat/k_m, respectively. HsGCK showed a 33% increase in affinity, 9% decrease in V_max, and a 50% increase in enzyme efficiency.

Conclusion

The observed pattern of hGCK and AgNPs falls under the uncompetitive inhibition. The observed highly selective inhibitory effects of AgNPs between TbHK and hGCK may be used in development of new anti-trypanosomal drugs.

Mitigation of SARS-CoV-2 by Using Transition Metal Nanozeolites and Quaternary Ammonium Compounds as Antiviral Agents in Suspensions and Soft Fabric Materials

Introduction

The coronavirus disease 2019 (COVID-19) pandemic has demonstrated the need for novel, affordable, and efficient reagents to help reduce viral transmission, especially in high-risk environments including medical treatment facilities, close quarters, and austere settings. We examined transition-metal nanozeolite suspensions and quaternary ammonium compounds as an antiviral surface coating for various textile materials.

Methods

Zeolites are crystalline porous aluminosilicate materials, with the ability of ion-exchanging different cations. Nanozeolites (30 nm) were synthesized and then ion-exchanged with silver, zinc and copper ions. Benzalkonium nitrate (BZN) was examined as the quaternary ammonium ion (quat). Suspensions of these materials were tested for antiviral activity towards SARS-CoV-2 using plaque assay and immunostaining. Suspensions of the nanozeolite and quat were deposited on polyester and cotton fabrics and the ability of these textiles towards neutralizing SARS-CoV-2 was examined.

Results

We hypothesized that transition metal ion containing zeolites, particularly silver and zinc (AM30) and silver and copper (AV30), would be effective in reducing the infectivity of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). Additionally, AM30 and AV30 antiviral potency was tested when combined with a quaternary ammonium carrier, BZN. Our results indicate that exposure of SARS-CoV-2 to AM30 and/or AV30 suspensions reduced viral loads with time and exhibited dose-dependence. Antiviral activities of the combination of zeolite and BZN compositions were significantly enhanced. When used in textiles, AM30 and AV30-coated cotton and polyester fabrics alone or in combination with BZN exhibited significant antiviral properties, which were maintained even after various stress tests, including washes, SARS-CoV-2-repeated exposures, or treatments with soil-like materials.

Conclusion

This study shows the efficacy of transition metal nanozeolite formulations as novel antiviral agents and establishes that nanozeolite with silver and zinc ions (AM30) and nanozeolite with silver and copper ions (AV30) when combined with benzalkonium nitrate (BZN) quickly and continuously inactivate SARS-CoV-2 in suspension and on fabric materials.

SARS-CoV-2 and its new variants: a comprehensive review on nanotechnological application insights into potential approaches

SARS-CoV-2 (COVID-19) spreads and develops quickly worldwide as a new global crisis which has left deep socio-economic damage and massive human mortality. This virus accounts for the ongoing outbreak and forces an urgent need to improve antiviral therapeutics and targeted diagnosing tools. Researchers have been working to find a new drug to combat the virus since the outbreak started in late 2019, but there are currently no successful drugs to control the SARS-CoV-2, which makes the situation riskier. Very recently, new variant of SARS-CoV-2 is identified in many countries which make the situation very critical. No successful treatment has yet been shown although enormous international commitment to combat this pandemic and the start of different clinical trials. Nanomedicine has outstanding potential to solve several specific health issues, like viruses, which are regarded a significant medical issue. In this review, we presented an up-to-date drug design strategy against SARS-CoV-2, including the development of novel drugs and repurposed product potentials were useful, and successful drugs discovery is a constant requirement. The use of nanomaterials in treatment against SARS-CoV-2 and their use as carriers for the transport of the most frequently used antiviral therapeutics are discussed systematically here. We also addressed the possibilities of practical applications of nanoparticles to give the status of COVID-19 antiviral systems.

Characterization of Ag-Ion Releasing Zeolite Filled 3D Printed Resins

There has been profound growth in the use of 3D printed materials in dentistry in general, including orthodontics. The opportunity to impart antimicrobial properties to 3D printed parts from existing resins requires the capability of forming a stable colloid incorporating antimicrobial fillers. The objective of this research was to characterize a colloid consisting of a 3D printable resin mixed with Ag-ion releasing zeolites and fumed silica to create 3D printed parts with antiviral properties. The final composite was tested for antiviral properties against SARS-CoV-2 and HIV-1. Antiviral activity was measured in terms of the half-life of SARS-CoV-2 and HIV-1 on the composite surface. The inclusion of the zeolite did not interfere with the kinetics measured on the surface of the ATR crystal. While the depth of cure, measured following ISO4049 guidelines, was reduced from 3.8 mm to 1.4 mm in 5 s, this greatly exceeded the resolution required for 3D printing. The colloid was stable for at least 6 months and the rheological behavior was dependent upon the fumed silica loading. The inclusion of zeolites and fumed silica significantly increased the flexural strength of the composite as measured by a 3 point bend test. The composite released approximately 2500 μg/L of silver ion per gram of composite as determined by potentiometry. There was a significant reduction of the average half-life of SARS-CoV-2 (1.9 fold) and HIV-1 (2.7 fold) on the surface of the composite. The inclusion of Ag-ion releasing zeolites into 3D-printable resin can result in stable colloids that generate composites with improved mechanical properties and antiviral properties.

Nano-antivirals: A comprehensive review

Nanoparticles can be used as inhibitory agents against various microorganisms, including bacteria, algae, archaea, fungi, and a huge class of viruses. The mechanism of action includes inhibiting the function of the cell membrane/stopping the synthesis of the cell membrane, disturbing the transduction of energy, producing toxic reactive oxygen species (ROS), and inhibiting or reducing RNA and DNA production. Various nanomaterials, including different metallic, silicon, and carbon-based nanomaterials and nanoarchitectures, have been successfully used against different viruses. Recent research strongly agrees that these nanoarchitecture-based virucidal materials (nano-antivirals) have shown activity in the solid state. Therefore, they are very useful in the development of several products, such as fabric and high-touch surfaces. This review thoroughly and critically identifies recently developed nano-antivirals and their products, nano-antiviral deposition methods on various substrates, and possible mechanisms of action. By considering the commercial viability of nano-antivirals, recommendations are made to develop scalable and sustainable nano-antiviral products with contact-killing properties.

Silver nanoparticles with excellent biocompatibility block pseudotyped SARS-CoV-2 in the presence of lung surfactant

Silver (Ag) is known to possess antimicrobial properties which is commonly attributed to soluble Ag ions. Here, we showed that Ag nanoparticles (NPs) potently inhibited SARS-CoV-2 infection using two different pseudovirus neutralization assays. We also evaluated a set of Ag nanoparticles of different sizes with varying surface properties, including polyvinylpyrrolidone (PVP)-coated and poly (ethylene glycol) (PEG)-modified Ag nanoparticles, and found that only the bare (unmodified) nanoparticles were able to prevent virus infection. For comparison, TiO₂ nanoparticles failed to intercept the virus. Proteins and lipids may adsorb to nanoparticles forming a so-called bio-corona; however, Ag nanoparticles pre-incubated with pulmonary surfactant retained their ability to block virus infection in the present model. Furthermore, the secondary structure of the spike protein of SARS-CoV-2 was perturbed by the Ag nanoparticles, but not by the ionic control (AgNO₃) nor by the TiO₂ nanoparticles. Finally, Ag nanoparticles were shown to be non-cytotoxic towards the human lung epithelial cell line BEAS-2B and this was confirmed by using primary human nasal epithelial cells. These results further support that Ag nanoparticles may find use as anti-viral agents.

Computer Simulation of the Interaction between SARS-CoV-2 Spike Protein and the Surface of Coinage Metals

A prominent feature of the SARS-CoV-2 virus is the presence of a large glycoprotein spike protruding from the virus envelope. The spike determines the interaction of the virus with the environment and the host. Here, we used an all-atom molecular dynamics simulation method to investigate the interaction of up- and down-conformations of the S1 subunit of the SARS-CoV-2 spike with the (100) surface of Au, Ag, and Cu. Our results revealed that the spike protein is adsorbed onto the surface of these metals, with Cu being the metal with the highest interaction with the spike. In our simulations, we considered the spike protein in both its up-conformation S^up (one receptor binding domain exposed) and down-conformation S^down (no exposed receptor binding domain). We found that the affinity of the metals for the up-conformation was higher than their affinity for the down-conformation. The structural changes in the spike in the up-conformation were also larger than the changes in the down-conformation. Comparing the present results for metals with those obtained in our previous MD simulations of S^up with other materials (cellulose, graphite, and human skin models), we see that Au induces the highest structural change in S^up, larger than those obtained in our previous studies.

Environmental Implications Associated with the Development of Nanotechnology: From Synthesis to Disposal

Nanotechnology remains under continuous development. The unique, fascinating, and tunable properties of nanomaterials make them interesting for diverse applications in different fields such as medicine, agriculture, and remediation. However, knowledge about the risks associated with nanomaterials is still poorly known and presents variable results. Furthermore, the interaction of nanomaterials with biological systems and the environment still needs to be clarified. Moreover, some issues such as toxicity, bioaccumulation, and physicochemical transformations are found to be dependent on several factors such as size, capping agent, and shape, making the comparisons even more complex. This review presents a comprehensive discussion about the consequences of the use and development of nanomaterials regarding their potential risks to the environment as well as human and animal health. For this purpose, we reviewed the entire production chain from manufacturing, product development, applications, and even product disposal to raise the important implications at each stage. In addition, we present the recent developments in terms of risk management and the recycling of nanomaterials. Furthermore, the advances and limitations in the legislation and characterization of nanomaterials are also discussed.

Highly active antiretroviral therapy-silver nanoparticle conjugate interacts with neuronal and glial cells and alleviates anxiety-like behaviour in streptozotocin-induced diabetic rats

The inception of highly active antiretroviral therapy (HAART) has changed the management of human immunodeficiency virus (HIV) positive patients, with an improvement in life expectancy. However, neurological complications associated with high dosage and chronic administration of HAART have not been fully addressed. Therefore, this study evaluated the potential benefits of silver nanoparticles (AgNPs) conjugated-HAART (HAART-AgNPs) and its interaction with neuronal and glial cells in type-2 diabetic rats. Forty-two (n = 42) adult male Sprague-Dawley rats (250 ± 13 g) were divided into non-diabetic and diabetic groups. Each rat was administered with either distilled water, HAART, or HAART-AgNPs for eight weeks. After that, the prefrontal cortex (PFC) was excised for immunohistochemical, biochemical, and ultrastructural analysis. The formulated HAART-AgNPs were characterised by Ultraviolet-Visible, Transmission electron microscope, Energy Dispersive X-ray and Fourier transform infrared spectroscopy. Of the various concentrations of HAART-AgNPs, 1.5 M exhibited 20.3 nm in size and a spherical shape was used for this study. Administration of HAART-AgNPs to diabetic rats significantly decreased (p < 0.05) blood glucose level, number of faecal pellets, malondialdehyde (MDA), tumour necrosis factor-alpha (TNF-α), Interleukin-1 beta (IL-1β) compared with HAART-treated diabetic rats. Notably, there was a significant increase (p < 0.05) in antioxidant biomarkers (SOD and GSH), improvement in PFC-glial fibrillary acid protein (PFC-GFAP) positive cells and alleviation of anxiety-like behaviour in HAART-AgNPs treated diabetic rats. These results showed that HAART-AgNPs alleviates the anxiogenic effect and neuronal toxicity aggravated by HAART exposure via the reduction of oxidative and neuroinflammatory injury as well as preserving PFC GFAP-positive cells and neuronal cytoarchitecture.

Functional silver nanoparticles synthesis from sustainable point of view: 2000 to 2023 ‒ A review on game changing materials

The green and facile synthesis of metallic silver nanoparticles (AgNPs) is getting tremendous attention for exploring superior applications because of their small dimensions and shape. AgNPs are already proven materials for superior coloration, biocidal, thermal, UV-protection, and mechanical performance. Originally, some conventional chemical-based reducing agents were used to synthesize AgNPs, but these posed potential risks, especially for enhanced toxicity. This became a driving force to innovate plant-based sustainable and green metallic nanoparticles (NPs). Moreover, the synthesized NPs using plant-based derivatives could be tuned and regulated to achieve the required shape and size of the AgNPs. AgNPs synthesized from naturally derived materials are safe, economical, eco-friendly, facile, and convenient, which is also motivating researchers to find greener routes and viable options, utilizing various parts of plants like flowers, stems, heartwood, leaves and carbohydrates like chitosan to meet the demands. This article intends to provide a comprehensive review of all aspects of AgNP materials, including green synthesis methodology and mechanism, incorporation of advanced technologies, morphological and elemental study, functional properties (coloration, UV-protection, biocidal, thermal, and mechanical properties), marketing value, future prospects and application, especially for the last 20 years or more. The article also includes a SWOT (Strengths, weaknesses, opportunities, and threats) analysis regarding the use of AgNPs. This report would facilitate the industries and consumers associated with AgNP synthesis and application through fulfilling the demand for sustainable, feasible, and low-cost product manufacturing protocols and their future prospects.

Evaluation of tenofovir disoproxil fumarate loaded silver nanoparticle on testicular morphology in experimental type-2 diabetic rats

Reproductive derangement and metabolic disorders in human immunodeficiency virus (HIV) infected persons require a nanoparticle delivery system to convey antiretroviral drugs to the anatomical sanctuary such as testis. This study investigated the effects of tenofovir disoproxil fumarate (TDF) loaded silver nanoparticles (AgNPs) on the testicular oxidative stress, inflammatory cytokines and histology in male diabetic rats. Thirty-six Sprague-Dawley rats weighing 230 ± 20 g were randomly divided into diabetic and non-diabetic groups (n = 18). Diabetes was induced using the fructose-streptozotocin (Frt-STZ) rat model. Both groups were further divided into three (n = 6) and administered distilled water, TDF, or TDF-AgNP. Results obtained with the TDF-AgNP administration showed a significant increase (p < .05) in the reduced glutathione and catalase levels. Tumour necrosis factor-alpha and interleukin 6 were reduced in diabetic rats administered TDF-AgNP. More so, administration of TDF-AgNP to diabetic rats improved testicular histoarchitecture in diabetic rats. In addition, diabetic rats administered TDF-AgNP showed a significant reduction (p < .05) in blood glucose levels. TDF-AgNP to diabetic rats enhanced testicular antioxidant enzyme, reduced testicular inflammation, and alleviated structural derangements in the testis. Thus, the application of AgNP to deliver TDF may alleviate testicular toxicity and subsequently cater for neglected reproductive dysfunction during the management of HIV infection.

Chronic toxicity of shrimp feed added with silver nanoparticles (Argovit-4®) in Litopenaeus vannamei and immune response to white spot syndrome virus infection

In recent years, the application of silver nanoparticles (AgNPs) as antibacterial compounds has been widely used in human and veterinary medicine. In this work, we investigated the effects of AgNPs (Argovit-4®) as feed additives (feed-AgNPs) on shrimp (Litopenaeus vannamei) using three different methods: 1) chronic toxicity after 28 days of feeding, 2) Effects against white spot syndrome virus (WSSV) challenged by oral route, and 3) transcriptional responses of immune-related genes (PAP, ProPO, CTL-3, Crustin, PEN3, and PEN4) following WSSV infection. The results showed that the feed-AgNPs did not interfere with the growth and survival of shrimp. Also, mild lesions in the hepatopancreas were recorded, proportional to the frequency of the feed-AgNP supply. Challenge test versus WSSV showed that feeding every 7 days with feed-AgNPs reduced mortality, reaching a survival rate of 53%, compared to the survival rates observed in groups fed every 4 days, daily and control groups of feed-AgNPs for the 30%, 10%, and 7% groups, respectively. Feed-AgNPs negatively regulated the expression of PAP, ProPO, and Crustin genes after 28 days of treatment and altered the transcriptional responses of PAP, ProPO, CTL-3, and Crustin after WSSV exposure. The results showed that weekly feeding-AgNPs could partially prevent WSSV infection in shrimp culture. However, whether or not transcriptional responses against pathogens are advantageous remains to be elucidated.

Antiviral efficacy of cerium oxide nanoparticles

Nanomaterials are prospective candidates for the elimination of viruses due to their multimodal mechanisms of action. Here, we tested the antiviral potential of a largely unexplored nanoparticle of cerium dioxide (CeO₂). Two nano-CeO₂ with opposing surface charge, (+) and (-), were assessed for their capability to decrease the plaque forming units (PFU) of four enveloped and two non-enveloped viruses during 1-h exposure. Statistically significant antiviral activity towards enveloped coronavirus SARS-CoV-2 and influenza virus was registered already at 20 mg Ce/l. For other two enveloped viruses, transmissible gastroenteritis virus and bacteriophage φ6, antiviral activity was evidenced at 200 mg Ce/l. As expected, the sensitivity of non-enveloped viruses towards nano-CeO₂ was significantly lower. EMCV picornavirus showed no decrease in PFU until the highest tested concentration, 2000 mg Ce/l and MS2 bacteriophage showed slight non-monotonic response to high concentrations of nano-CeO₂(-). Parallel testing of antiviral activity of Ce³⁺ ions and SiO₂ nanoparticles allows to conclude that nano-CeO₂ activity was neither due to released Ce-ions nor nonspecific effects of nanoparticulates. Moreover, we evidenced higher antiviral efficacy of nano-CeO₂ compared with Ag nanoparticles. This result along with low antibacterial activity and non-existent cytotoxicity of nano-CeO₂ allow us to propose CeO₂ nanoparticles for specific antiviral applications.

Narrative review on century of respiratory pandemics from Spanish flu to COVID-19 and impact of nanotechnology on COVID-19 diagnosis and immune system boosting

The rise of the highly lethal severe acute respiratory syndrome-2 (SARS-2) as corona virus 2019 (COVID-19) reminded us of the history of other pandemics that happened in the last century (Spanish flu) and stayed in the current century, which include Severe-Acute-Respiratory-Syndrome (SARS), Middle-East-Respiratory-Syndrome (MERS), Corona Virus 2019 (COVID-19). We review in this report the newest findings and data on the origin of pandemic respiratory viral diseases, reservoirs, and transmission modes. We analyzed viral adaption needed for host switch and determinants of pathogenicity, causative factors of pandemic viruses, and symptoms and clinical manifestations. After that, we concluded the host factors associated with pandemics morbidity and mortality (immune responses and immunopathology, ages, and effect of pandemics on pregnancy). Additionally, we focused on the burdens of COVID-19, non-pharmaceutical interventions (quarantine, mass gatherings, facemasks, and hygiene), and medical interventions (antiviral therapies and vaccines). Finally, we investigated the nanotechnology between COVID-19 analysis and immune system boosting (Nanoparticles (NPs), antimicrobial NPs as antivirals and immune cytokines). This review presents insights about using nanomaterials to treat COVID-19, improve the bioavailability of the abused drugs, diminish their toxicity, and improve their performance.

Thermoplasmonics Decontamination of Respirators Face Masks Using Silver Nanoparticles: A New Weapon in the Fight Against COVID-19 Pandemic

The current COVID-19 pandemic has resulted in an urgent need for methods to decontaminate respirators masks for reuse while keeping them intact and functional. The severe shortage of professional masks such as N95 and FFP2 has necessitated their reuse over long periods. A very promising method is the pasteurization of these masks by thermoplasmonic heat generated by plasmonics nanoparticles when they are irradiated by light. Under illumination at its plasmonic resonance, a metal nanoparticle features enhanced light absorption, turning it into an ideal nano-source of heat, remotely controllable using light. In this work, we propose a numerical study based on the finite element method (FEM) of the thermoplasmonic properties of silver nanoparticles (AgNPs) decorating polypropylene (PP) fibers which is a basic material for the manufacture of these masks. The surface plasmon resonance (SPR) of these nanostructures was investigated through the computation of the complex effective dielectric permittivity and the absorption cross section in the near UV-visible (NUV-Vis) range. First, the SPR characteristics of AgNPs for different morphologies are determined from the absorption spectra, including the SPR-peak position λ_max and the electric field enhancement. Second, we determine the power absorbed by an individual AgNP of different morphologies. From this, we calculate the internal temperature increase of the particle at the plasmonic resonance. The last step is devoted to the determination of the temperature profile in the surrounding medium in order to better understand and design the plasmon-assisted heating processes at the nanometric scale.

Amine-Functionalized Silver Nanoparticles: A Potential Antiviral-Coating Material with Trap and Kill Efficiency to Combat Viral Dissemination (COVID-19)

The outbreak of COVID-19 has drastically affected the daily lifestyles of people globally where specific Coronavirus-2 transmits primarily by respiratory droplets. Structurally, the SARS-CoV-2 virus is made up of four types of proteins in which S-protein is indispensable among them, as it causes rapid replication in the host body. Therefore, the glycine and alanine composed of HR1 of S-protein is the ideal target for antiviral action. Different forms of surface-active PPEs can efficiently prevent this transmission in this circumstance. However, the virus can survive on the conventional PPEs for a long time. Hence, the nanotechnological approaches based on engineered nanomaterials coating on medical equipments can potentially prevent the dissemination of infections in public. Silver nanoparticles with tuneable physicochemical properties and versatile chemical functionalization provide an excellent platform to combat the disease. The coating of amine-functionalized silver nanoparticle (especially amine linked to aliphatic chain and trialkoxysilane) in its nanostructured form enables cloths trap and kill efficient. PPEs are a primary and reliable preventive measure, although they are not 100% effective against viral infections. So, developing and commercializing surface-active PPEs with trap and kill efficacy is highly needed to cope with current and future viral infections. This review article discusses the COVID-19 morphology, antiviral mechanism of Ag-NPs against SARS-CoV-2 virus, surface factors that influence viral persistence on fomites, the necessity of antiviral PPEs, and the potential application of amine-functionalized silver nanoparticles as a coating material for the development of trap and kill-efficient face masks and PPE kits.

Passive antifouling and active self-disinfecting antiviral surfaces

Viruses pose a serious threat to human health and society in general, as virus infections are one of the main causes of morbidity and mortality. Till May 2022, over 513 million people around the world have been confirmed to be infected and more than 6.2 million have died due to SARS-CoV-2. Although the COVID-19 pandemic will be defeated in the near future, we are likely to face new viral threats in the coming years. One of the important instruments to protect from viruses are antiviral surfaces, which are essentially capable of limiting their spread. The formulation of the concept of antiviral surfaces is relatively new. In general, five types of mechanism directed against virus spread can be proposed for antiviral surfaces; involving: direct and indirect actions, receptor inactivation, photothermal effect, and antifouling behavior. All antiviral surfaces can be classified into two main types - passive and active. Passive antiviral surfaces are based on superhydrophobic coatings that are able to repel virus contaminated droplets. In turn, viruses can become biologically inert (e.g., blocked or destroyed) upon contact with active antiviral surfaces, as they contain antiviral agents: metal atoms, synthetic or natural polymers, and small molecules. The functionality of antiviral surfaces can be significantly improved with additional properties, such as temperature- or pH-responsivity, multifunctionality, non-specific action on different virus types, long-term application, high antiviral efficiency and self-cleaning.

Polypropylene Modified with Ag-Based Semiconductors as a Potential Material against SARS-CoV-2 and Other Pathogens

The worldwide outbreak of the coronavirus pandemic (COVID-19) and other emerging infections are difficult and sometimes impossible to treat, making them one of the major public health problems of our time. It is noteworthy that Ag-based semiconductors can help orchestrate several strategies to fight this serious societal issue. In this work, we present the synthesis of α-Ag₂WO₄, β-Ag₂MoO₄, and Ag₂CrO₄ and their immobilization in polypropylene in the amounts of 0.5, 1.0, and 3.0 wt %, respectively. The antimicrobial activity of the composites was investigated against the Gram-negative bacterium Escherichia coli, the Gram-positive bacterium Staphylococcus aureus, and the fungus Candida albicans. The best antimicrobial efficiency was achieved by the composite with α-Ag₂WO₄, which completely eliminated the microorganisms in up to 4 h of exposure. The composites were also tested for the inhibition of SARS-CoV-2 virus, showing antiviral efficiency higher than 98% in just 10 min. Additionally, we evaluated the stability of the antimicrobial activity, resulting in constant inhibition, even after material aging. The antimicrobial activity of the compounds was attributed to the production of reactive oxygen species by the semiconductors, which can induce high local oxidative stress, causing the death of these microorganisms.

In ovo nano-silver and nutrient supplementation improves immunity and resistance against Newcastle disease virus challenge in broiler chickens

Silver nanoparticles (AgNPs) interact with the microbes and host immune system to protect against diseases. Fertile broiler eggs (n = 900) were allotted to six groups: un-injected control, sham (sterile water), AgNPs (50 μg), AgNPs+Amino acids (Methionine-10 mg + Arginine-25 mg), AgNPs+Vitamins (Vit B1-72μg + Vit B6-140μg), and AgNPs+Trace Elements (Zn-80 μg and Se-0.3 μg) and incubated for 18 days. On 18th embryonic day, 0.6 ml test solution was injected at the broad end of egg using 25 mm needle and transferred to hatcher. Post-hatch, half of the chicks from each group were vaccinated with Newcastle disease (ND) vaccine, and the other half were kept as unvaccinated unit and reared for 42 d with standard management practices. Hatchability, 1st and 42nd d body weight, feed intake, and feed conversion ratio were similar between treatment groups in both vaccinated and unvaccinated units. The relative weight of bursa Fabricius and thymus was similar, but spleen weight was higher (P ≤ 0.05) in AgNPs, AgNPs+Vits, and AgNPs+TEs chicks than control group. Cellular immune response (against mitogen phytohemagglutinin-P) was higher (P ≤ 0.05) in AgNPs+TEs chicks, whereas HA titer against sheep red blood cells antigen, serum IgG, IgM, and HI titer against ND vaccine was apparently higher in AgNPs+Vits group chicks than control. No clinical symptoms were observed in the vaccinated groups except for a few control birds 6 days postchallenge (PC). Three days PC, unvaccinated birds show depression, off feed, greenish diarrhea, and nasal discharge and the control group started dying. The highest cumulative infection (CI) was observed in sham (79.17%) and un-injected control (75%), but lowest in AgNPs+AAs birds (58.33%) on 3rd dpi. The CI reached 100% on 5th dpi in control groups and AgNPs, and 91.67% and 93.75% in AgNPs+TEs and AgNPs+AAs group, respectively. The AgNPs+TEs and AgNPs+AAs group birds lived for more than 90 h compared to 75 h in control groups and also had higher IL-6 and IL-2 gene expressions at 24 h PC. It was concluded that 50 μg/egg AgNPs with vitamins (B1 and B6) and trace elements (Zn and Se) improved performance, but AgNPs with trace elements and amino acids enhanced immune response and resistance against vND virus challenge in broilers.

Development of novel antiviral nanofinishes for bioactive textiles

Virus-caused public health outbreaks represent a serious threat to humans all over the world. The rampant new 2019 coronavirus (SARS-CoV-2) has wreaked havoc on China and the rest of the world since December 2019. Now focus is on effective reduction of corona and other viral and bacterial infections in hospitals, public and private sectors, households, schools, etc. Metal and metal oxide nanoparticles, carbon nanotubes, heterostructures, patterned surfaces, and graphene-based materials have shown up to 99.9998% efficacy against bacteria, mold, and viruses. The stability, long shelf life, and robustness of inorganic nanoparticles make them desirable for antimicrobial nanofinishes. These inorganic antimicrobial agents are more stable than organic antibacterial compounds at high temperature and pressure. The high specific surface area-to-volume ratios and unique physicochemical characteristics of nanoparticles are largely responsible for their antibacterial actions. But their immobilization is a huge challenge. To address this issue, NPs were modified with (glycidoxypropyl) trimethoxysilane (GPTS) and applied on cotton fabric. The silane part of GPTS reacted with the NPs under acidic conditions while epoxy reacted with cotton under alkaline conditions. Treated cotton fabric showed good antiviral and antibacterial activity even after severe industrial washing.

Graphical abstract

Reactive silver inks for antiviral, repellent medical textiles with ultrasonic bleach washing durability compared to silver nanoparticles

Medical textiles are subject to particularly harsh disinfection procedures in healthcare settings where exposure risks are high. This work demonstrates a fabric treatment consisting of a reactive silver ink and low surface energy PDMS polymer that provides for superhydrophobicity and antiviral properties against enveloped herpes simplex virus stocks even after extended ultrasonic bleach washing. The antiviral properties of reactive silver ink has not been previously reported or compared with silver nanoparticles. The fabric treatment exhibits high static contact angles and low contact angle hysteresis with water, even after 300 minutes of ultrasonic bleach washing. Similarly, after this bleach washing treatment, the fabric treatment shows reductions of infectious virus quantities by about 2 logs compared to controls for enveloped viruses. The use of silver ink provides for better antiviral efficacy and durability compared to silver nanoparticles due to the use of reactive ionic silver, which demonstrates more conformal coverage of fabric microfibers and better adhesion. This study provides insights for improving the wash durability of antiviral silver fabric treatments and demonstrates a bleach wash durable, repellent antiviral treatment for reusable, functional personal protective equipment applications.

Nanosilver inhibits the progression of pancreatic cancer by inducing a paraptosis-like mixed type of cell death

Silver has been in clinical use since ancient times and silver nanoparticles (AgNPs) have attracted attention in cancer therapy. We investigated the mechanisms by which AgNPs inhibit pancreatic ductal adenocarcinoma (PDAC). AgNPs were synthesized and 3 human PDAC and 2 nonmalignant primary cell lines were treated with AgNPs. MTT, MAPK, colony, spheroid and scratch assays, Western blotting, TEM, annexin V, 7-AAD, and H2DCFDA staining, FACS analysis, mRNA array and bioinformatics analyses, tumor xenograft transplantation, and immunohistochemistry of the treated cells were performed. We found that minimal AgNPs amounts selectively eradicated PDAC cells within a few hours. AgNPs inhibited cell migration and spheroid and colony formation, damaged mitochondria, and induced paraptosis-like cell death with the presence of cytoplasmic vacuoles, dilation of the ER and mitochondria, ROS formation, MAPK activity, and p62 and LC3b expression, whereas effects on the nucleus, DNA fragmentation, or caspases were not detectable. AgNPs strongly decreased tumor xenograft growth without side effects and reduced the expression of markers for proliferation and DNA repair, but upregulated paraptosis markers. The results highlight nanosilver as complementary agent to improve the therapeutic efficacy in pancreatic cancer.

Exploring the Potential of Metal Nanoparticles as a Possible Therapeutic Adjunct for Covid-19 Infection

The WHO has declared the Covid-19 outbreak as a global health emergency with a mortality rate of approximately 3%, across 200 countries. There has been a considerable risk involved with drug repurposing in Covid-19 treatment, particularly in patients with underlying chronic disorders. Intervention of appropriate adjunct to primary drug therapy at subclinical or clinical doses may help to reduce unintended consequences involved in Covid-19 therapy. Metal nanoparticles due to their intrinsic structural and functional properties, not only contribute to anti-viral properties but also help to reduce the risk for associated complications. Although, silver nanoparticles hold great promise as an effective biocidal agent, while other metal nanoparticles also fueled interest against virus infection. The present review discusses the important properties of selected metal nanoparticles, their antiviral principle with possible toxic consequences, provides invaluable information for scientists and clinicians about an appropriate metal nanoparticle as an adjunct for Covid-19 treatment.

Applications of Gold and Silver Nanoparticles in Theranostics

Nanotechnology sculptures the current scenario of science and technology. The word nano refers 'small' which ranges from 10 to 100 nm in size. Silver and gold nanoparticles can be synthesized at nanoscale and have unique biological properties like antibacterial, antifungal, antiviral, antiparasitic, antiplatelet, anti-inflammatory, and anti-tumor activity. In this mini review, we shall discuss the various applications of silver and gold nanoparticles (AuNPs) in the field of therapy, imaging, biomedical devices and in cancer diagnosis. The usage of silver nanoparticles(AgNPs) in dentistry and dental implants, therapeutic abilities like wound dressings, silver impregnated catheters, ventricular drainage catheters, combating orthopedic infections, and osteointegration will be elaborated. Gold nanoparticles in recent years have garnered large importance in bio medical applications. They are being used in diagnosis and have recently seen a surge in therapeutics. In this mini review, we shall see about the various applications of AuNP and AgNP, and highlight their evolution in theranostics.

Synthesis and Biological Characterization of Phyto-Fabricated Silver Nanoparticles from Azadirachta indica

Nanoparticles (NPs) have garnered a lot of interest in sectors like medicine, cosmetics, food, and pharmaceuticals for antibacterial catalytic properties, reduced toxicity, and easy production. Biological synthesis of silver nanoparticle (AgNPs) is considered as green, eco-friendly, and cost-effective approach; therefore, Azadirachta indica extracts were utilized for a dual role of fabrication and functionalization of AgNPs. Optical and physical characterizations were achieved for confirming the biosynthesized AgNPs. SEM images detected quasi-spherical AgNPs of 44.04 to 66.50 nm. Some of potent phytochemicals like flavonoids and proteins from Azadirachta indica formed a strong coating or capping on the AgNPs without affecting their secondary structure by interacting with Ag+ and NPs for the formation of AgNPs. AgNPs exhibited strong antibacterial activity (MIC 10 μg/ml) against multidrug-resistant bacteria Enterococcus faecalis; at different concentrations, no IC50 values were recorded for AgNPs as well as Azadirachta indica signifying low cytotoxicity in the exposed concentration range. The DNA degradation activity of AgNPs through the TUNEL assay revealed no significant increase in the overall FITC mean fluorescence intensity as well as a DNA fragmentation index with 5.45% DNA damage (10 μg/ml AgNPs). Drug uptake of AgNPs was also investigated through a permeability assay via Caco-2 cell lines at test concentrations where apparent permeability was detected as moderate.

Nanoparticles in clinical trials of COVID-19: An update

Once the World Health Organization (WHO) declared the COVID-19 (Coronavirus Infectious Disease-19) outbreak to be pandemic, massive efforts have been launched by researchers around the globe to combat this emerging infectious disease. Strategies that must be investigated such as expanding testing capabilities, developing effective medicines, as well as developing safe and effective vaccines for COVID-19 disease that produce long-lasting immunity to human system. Now-a-days, bio-sensing, medication delivery, imaging, and antimicrobial treatment are just a few of the medical applications for nanoparticles (NPs). Since the early 1990s, nanoparticle drug delivery methods have been employed in clinical trials. Since then, the discipline of nanomedicine has evolved in tandem with expanding technological demands to better medicinal delivery. Newer generations of NPs have emerged in recent decades that are capable of performing additional delivery tasks, allowing for therapy via novel therapeutic modalities. Many of these next generation NPs and associated products have entered clinical trials and have been approved for diverse indications in the present clinical environment. For systemic applications, NPs or nanomedicine-based drug delivery systems have substantial benefits over their non-formulated and free drug counterparts. Nanoparticle systems, for example, are capable of delivering medicines and treating parts of the body that are inaccessible to existing delivery systems. As a result, NPs medication delivery is one of the most studied preclinical and clinical systems. NPs-based vaccines delivering SARS-CoV-2 antigens will play an increasingly important role in prolonging or improving COVID-19 vaccination outcomes. This review provides insights about employing NPs-based drug delivery systems for the treatment of COVID-19 to increase the bioavailability of current drugs, reducing their toxicity, and to increase their efficiency. This article also exhibits their capability and efficacy, and highlighting the future aspects and challenges on nanoparticle products in clinical trials of COVID-19.

In Vivo Effects of Orally Administered Different Concentrations of Silver Oxide Nanoparticles in Hyperuricemic Mice

Silver oxide nanoparticles (AgO-NPs) antioxidant, anti-cancer, anti-microbial, and tissue repair properties. Gouty arthritis is the inflammation of tissues and joints caused by the deposition of monosodium urate crystals. In this experiment, we investigated the anti-hyperuricemic effectiveness of different concentrations of AgO-NPs in mice. The present study aimed to investigate the effect of administration of AgO-NPs in monosodium urate (MSU)-induced gouty mice for the very first time. Monosodium urate (MSU) crystals were administered intraperitoneal for gout induction, followed by 5, 10, and 20 µg/mL doses of AgO-NPs for 2 weeks. The positive control was provided with the commercially available drug allopurinol to compare the effects of AgO-NPs and allopurinol. The main purpose of the study was to investigate the effectiveness of the nanoparticles in comparison with commercially available drugs. AgO-NPs have been shown to improve the condition of gouty arthritis by reducing significantly (P ˂ 0.001) increased levels of ALT, AST, and total bilirubin. The total protein estimation results showed significant improvement at concentration of 20 µg/mL of AgO-NPs. The lipid profile results showed that high concentration (20 µg/mL) of AgO-NPs decrease the lipid content significantly as compared to control. It was concluded from this study that the antioxidant, anti-inflammatory, and antilipidemic properties of AgO-NPs may improve the hyperuricemic condition in gouty arthritis mice.

Tenofovir-silver nanoparticles conjugate ameliorates neurocognitive disorders and protects ultrastructural and cytoarchitectonic properties of the prefrontal cortex in diabetic rats

Tenofovir disoproxil fumarate (TDF) is the highly recommended antiretroviral drug in human immunodeficiency virus management. Although research has shown the neurological and metabolic disorders associated with TDF administration, the effect of TDF-silver nanoparticles conjugate (TDF-AgNPs) on the disorders has not been fully elucidated. Thus, this study evaluated the neuroprotective effects of TDF-AgNPs on ultrastructural and cytoarchitectonic properties of the prefrontal cortex (PFC) in diabetic rats. Forty-two adult male Sprague-Dawley rats (250 ± 13 g) were randomly divided into non-diabetic groups (1-3) and diabetic groups (4-6), each administered distilled water (0.5 ml/100g, p.o), TDF (26.8 mg/kg/bw, p.o) or TDF-AgNPs (6.7 mg/kg, i.p). After eight weeks of administration, cognitive function, oxidative injury and tissue inflammation were evaluated. Also, PFC ultrastructure was observed using transmission electron microscopy, Nissl staining and immunohistochemistry. Diabetic rats administered TDF exhibited cognitive deficits; and increases in blood glucose, malondialdehyde and interleukin-1 beta (IL-1β) levels, which correlate with decreases in glutathione level, and superoxide dismutase (SOD) and catalase activities. Furthermore, loss of PFC astrocytes and neuronal organelles was observed. Conversely, TDF-AgNPs administration to diabetic rats improved cognitive deficits; and increased glutathione, SOD, and catalase, but reduced PFC malondialdehyde and IL-1β concentrations. Notably, TDF-AgNPs prevented loss of PFC neurons and astrocytic cells, and morphology aberration of neuronal organelles. This study suggests that TDF-AgNPs attenuated cognitive deficits via silver nanoparticles' antioxidant and anti-inflammatory properties, preventing the loss of PFC astrocytes and neurons. The TDF-AgNPs may be utilized to ameliorate the neurological dysfunction caused by prolonged TDF administration.

Antiviral effects of coinage metal-based nanomaterials to combat COVID-19 and its variants

The world has been suffering from the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) pandemic, and millions of people have been infected through human-to-human transmission and lost their lives within months. Although multidisciplinary scientific approaches have been employed to fight against this deadly pandemic, various mutations and diverse environments keep producing constraints in treating SARS-CoV-2. Indeed, the efficacy of the developed vaccines has been limited, and inoculation with the vaccines does not guarantee complete protection even though multiple doses are required, which is a frustrating process. Historically, coinage metals (Cu, Ag, and Au) have been well-known for their effectiveness in antiviral action as well as good biocompatibility, binding receptor inhibition, reactive oxygen species, and phototherapy properties. Thus, this review highlights the diagnostic and therapeutic mechanisms of SARS-CoV-2 using the antivirus ability and mode of action of coinage metals such as viral entry mechanisms into host cells and the NP-inhibition process, which are explained in detail. This article also draws attention to coinage metal nanomaterial-based approaches to treat other contagious viruses. In addition, coinage metal-based biosensors and an overview of some other biocompatible metal-based nanomaterials to fight against SARS-CoV-2 variants are discussed. Finally, the advantages, perspectives and challenges of coinage metal nanoparticles are given to fight against viral infections in the future.

Synthesis and Characterization of Tween-20 Capped Biosynthesized Silver Nanoparticles for Anticancer and Antimicrobial Property

The Vitrus vinifera fruit extract was used to make silver nanoparticles (AgNPs) utilizing a green chemical technique. The biosynthesized Tween-20/Vitrus vinifera-AgNPs were observed by UV-Vis spectrophotometry. Fourier transform infrared spectroscopy, scanning transmission electron microscopy, selected area electron diffraction, and energy-dispersive X-ray spectroscopy were used to characterize the physiochemical properties. The spherical form of AgNPs was confirmed by transmission electron microscopy. The peaks in the Tween-20/Vitrus vinifera-AgNPs have an average crystallite size that is found to be 46 nm according to powder X-ray diffraction examination. Biosynthesized AgNPs had a significant effect on bone osteosarcoma MG63 cells with 55% inhibition, respectively, using MTT assay. The effective dangerous concentration of Tween-20/Vitrus vinifera with AgNP nanoparticles was less harmful to MG63 cells. The results of antibacterial activity showed that Tween-20/Vitrus vinifera-AgNPs effectively inhibited Eggerthella lenta and Staphylococcus epidermis bacteria.

Antiviral potential of nanoparticles for the treatment of Coronavirus infections

BACKGROUND

On 31st December 2019 in Wuhan, China, severe acute respiratory syndrome coronavirus-2 (SARS-CoV-2), was acknowledged. This virus spread quickly throughout the world causing a global pandemic. The World Health Organization declared COVID-19 a pandemic disease on 11th March 2020. Since then, the whole world has come together and have developed several vaccines against this deadly virus. Similarly, several alternative searches for pandemic disease therapeutics are still ongoing. One of them has been identified as nanotechnology. It has demonstrated significant promise for detecting and inhibiting a variety of viruses, including coronaviruses. Several nanoparticles, including gold nanoparticles, silver nanoparticles, quantum dots, carbon dots, graphene oxide nanoparticles, and zinc oxide nanoparticles, have previously demonstrated remarkable antiviral activity against a diverse array of viruses.

OBJECTIVE

This review aims to provide a basic and comprehensive overview of COVID-19's initial global outbreak and its mechanism of infiltration into human host cells, as well as the detailed mechanism and inhibitory effects of various nanoparticles against this virus. In addition to nanoparticles, this review focuses on the role of several antiviral drugs used against COVID-19 to date.

CONCLUSION

COVID-19 has severely disrupted the social and economic lives of people all over the world. Due to a lack of adequate medical facilities, countries have struggled to maintain control of the situation. Neither a drug nor a vaccine has a 100% efficacy rate. As a result, nanotechnology may be a better therapeutic alternative for this pandemic disease.

Advances in Nanotechnology as a Potential Alternative for Plant Viral Disease Management

Plant viruses cause enormous losses in agricultural production accounting for about 47% of the total overall crop losses caused by plant pathogens. More than 50% of the emerging plant diseases are reported to be caused by viruses, which are inevitable or unmanageable. Therefore, it is essential to devise novel and effective management strategies to combat the losses caused by the plant virus in economically important crops. Nanotechnology presents a new tendency against the increasing challenges in the diagnosis and management of plant viruses as well as plant health. The application of nanotechnology in plant virology, known as nanophytovirology, includes disease diagnostics, drug delivery, genetic transformation, therapeutants, plant defense induction, and bio-stimulation; however, it is still in the nascent stage. The unique physicochemical properties of particles in the nanoscale allow greater interaction and it may knock out the virus particles. Thus, it opens up a novel arena for the management of plant viral diseases. The main objective of this review is to focus on the mounting collection of tools and techniques involved in the viral disease diagnosis and management and to elucidate their mode of action along with toxicological concerns.

Structure-Morphology-Antimicrobial and Antiviral Activity Relationship in Silver-Containing Nanocomposites Based on Polylactide

Green synthesis of silver-containing nanocomposites based on polylactide (PLA) was carried out in two ways. With the use of green tea extract, Ag⁺ ions were reduced to silver nanoparticles with their subsequent introduction into the PLA (mechanical method) and Ag⁺ ions were reduced in the polymer matrix of PLA-AgPalmitate (PLA-AgPalm) (in situ method). Structure, morphology and thermophysical properties of nanocomposites PLA-Ag were studied by FTIR spectroscopy, wide-angle X-ray scattering (WAXS), transmission electron microscopy (TEM), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) methods. The antimicrobial, antiviral, and cytotoxic properties were studied as well. It was found that the mechanical method provides the average size of silver nanoparticles in the PLA of about 16 nm, while in the formation of samples by the in situ method their average size was 3.7 nm. The strong influence of smaller silver nanoparticles (3.7 nm) on the properties of nanocomposites was revealed, as with increasing nanosilver concentration the heat resistance and glass transition temperature of the samples decreases, while the influence of larger particles (16 nm) on these parameters was not detected. It was shown that silver-containing nanocomposites formed in situ demonstrate antimicrobial activity against gram-positive bacterium S. aureus, gram-negative bacteria E. coli, P. aeruginosa, and the fungal pathogen of C. albicans, and the activity of the samples increases with increasing nanoparticle concentration. Silver-containing nanocomposites formed by the mechanical method have not shown antimicrobial activity. The relative antiviral activity of nanocomposites obtained by two methods against influenza A virus, and adenovirus serotype 2 was also revealed. The obtained nanocomposites were not-cytotoxic, and they did not inhibit the viability of MDCK or Hep-2 cell cultures.

Analysis of Silver Nanoparticles for the Treatment and Prevention of Nucleopolyhedrovirus Affecting Bombyx mori

Bombyx mori nucleopolyhedrovirus (BmNPV) causes major economic losses in sericulture. A number of agents have been employed to treat viral diseases. Silver nanoparticles (AgNPs) have wide applications in biomedical fields due to their unique properties. The anti-BmNPV effect of AgNPs has been evaluated, however, there are insufficient studies concerning its toxicity to other organisms and the environment. We chemically synthesized biocompatible BSA-AgNPs with a diameter range of 2–4 nm and characterized their physical properties. The toxicity of AgNPs towards cells and larvae with different concentrations was examined; the results indicated a biofriendly effect on cells and larvae within specific concentration ranges. The SEM observation of the surface of BmNPV after treatment with AgNPs suggested that AgNPs could destroy the polyhedral structure, and the same result was obtained by Coomassie blue staining. Further assays confirmed the weakened virulence of AgNPs-treated BmNPV toward cells and larvae. AgNPs also could effectively inhibit the replication of BmNPV in infected cells and larvae. In summary, our research provides valuable data for the further development of AgNPs as an antiviral drug for sericulture.

Preparation, Characterization, and Antimicrobial and Antiviral Properties of Silver-Containing Nanocomposites Based on Polylactic Acid-Chitosan

Antimicrobial and antiviral nanocomposites based on polylactic acid (PLA) and chitosan were synthesized by a thermochemical reduction method of Ag⁺ ions in the PLA-Ag⁺-chitosan polymer films. Features of the structural, morphological, thermophysical, antimicrobial, antiviral, and cytotoxic properties of PLA-Ag-chitosan nanocomposites were studied by X-ray diffraction (XRD), transmission electron microscopy (TEM), differential scanning calorimetry (DSC), thermogravimetric analysis (TGA), and antiviral, antimicrobial, and cytotoxic studies. The effects of temperature and the duration of reduction of Ag⁺ ions on the structure of PLA-Ag-chitosan nanocomposites were established. During the thermochemical reduction (T = 160 °C, t = 5 min) of silver palmitate ions in PLA-Ag⁺-chitosan polymer films, Ag nanoparticles with an average size of 4.2 nm were formed. PLA-Ag-chitosan polymer nanocomposites have strong antimicrobial activity against S. aureus and E. coli strains. In particular, for PLA-chitosan samples containing 4% Ag, the diameters of the S. aureus and E. coli growth inhibition zones were 25.8 and 25.0 mm, respectively. The antiviral activity of the nanocomposites against influenza A virus, herpes simplex virus type 1, and adenovirus serotype 2 was also revealed. The PLA-4%Ag-chitosan nanocomposites completely inhibited the cytopathic effect (CPE) of herpes virus type 1 by 5.12 log₁₀TCID₅₀/mL (high antiviral activity) and the development of the CPE of influenza virus and adenovirus by 0.60 and 1.07 log₁₀TCID₅₀/mL (relative antiviral activity). The obtained nanocomposites were not cytotoxic; they did not inhibit the viability of MDCK, BHK-21, and Hep-2 cell cultures.

Role of Antimicrobial Drug in the Development of Potential Therapeutics

Population of the world run into several health-related emergencies among mankind and humans as it creates a challenge for the evolution of novel drug discoveries. One such can be the emergence of multidrug-resistant (MDR) strains in both hospital and community settings, which have been due to an inappropriate use and inadequate control of antibiotics that has led to the foremost human health concerns with a high impact on the global economy. So far, there has been application of two strategies for the development of anti-infective agents either by classical antibiotics that have been derived for their synthetic analogs with increased efficacy or screening natural compounds along with the synthetic compound libraries for the antimicrobial activities. However, need for newer treatment options for infectious diseases has led research to develop new generation of antimicrobial activity to further lessen the spread of antibiotic resistance. Currently, the principles aim to find novel mode of actions or products to target the specific sites and virulence factors in pathogens by a series of better understanding of physiology and molecular aspects of the microbial resistance, mechanism of infection process, and gene-pathogenicity relationship. The design various novel strategies tends to provide us a path for the development of various antimicrobial therapies that intends to have a broader and wider antimicrobial spectrum that helps to combat MDR strains worldwide. The development of antimicrobial peptides, metabolites derived from plants, microbes, phage-based antimicrobial agents, use of metal nanoparticles, and role of CRISPR have led to an exceptional strategies in designing and developing the next-generation antimicrobials. These novel strategies might help to combat the seriousness of the infection rates and control the health crisis system.

Myco-Facilitated Biosynthesis of Nano-Silver From Wasp Nest Fungus, Paecilomyces variotii, and Its Antimicrobial Activity Against MTCC Strains

The utility of fungi as stabilizing and reducing agents in the biogenic synthesis of silver nanoparticles is striking due to the production of large quantities of biomolecules of minute toxic residuals. During the current study, sunlight- and dark-assessed silver nanoparticles were synthesized from wasp nest fungus, Paecilomyces variotii, at different pHs. Synthesized silver nanoparticles (AgNPs) at 6 pH were found to be more prominent than at 7 and 8 pHs. AgNPs were within the 20- to 90-nm range and were polygonal and elongated in shape. FTIR spectra of light-mediated AgNPs showed diverse transmittance bands than the silver nanoparticles synthesized in the dark. The synthesized AgNPs were found with diverse antimicrobial activities against pathogenic MTCC bacterial strains, i.e., Staphylococcus aureus, Vibrio parahaemolyticus, Escherichia coli, Shewanella putrefaciens, and fungus, Candida albicans. Aqueous filtrate and filtrate-mediated AgNPs combined with methanol solvent extract of yeast extract manitol broth (YEMB) had more inhibitory effects on all bacteria and Candida albicans. Furthermore, the combined effect of AgNPs and methanol solvent extract from YEMB culture filtrate was found more effective against E. coli, while AgNPs combined with methanol solvent of aqueous filtrate had inhibitory effects on E. coli and Candida albicans.

Recent advances in carbon quantum dots for virus detection, as well as inhibition and treatment of viral infection

In the last decade, carbon quantum dots (CQDs), as a novel class of carbon-based nanomaterials, have received increasing attention due to their distinct properties. CQDs are ultimately small nanoparticles with an average size below 10 nm, possessing high water solubility, alluring photoluminescence, photostability, excellent biocompatibility, low/none toxicity, environmental friendliness, and high sustainability, etc. In history, there are intermittent threats from viruses to humans, animals and plants worldwide, resulting in enormous crises and impacts on our life, environment, economy and society. Some recent studies have unveiled that certain types of CQDs exhibited high and potent antiviral activities against various viruses such as human coronavirus, arterivirus, norovirus and herpesvirus. Moreover, they have been successfully explored and developed for different virus detections including severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). This article exclusively overviews and discusses the recent progress of designing, synthesizing, modifying/functionalizing and developing CQDs towards effective virus detection as well as the inhibition and treatment of viral infection. Their mechanisms and applications against various pathogenic viruses are addressed. The latest outcomes for combating the coronavirus disease 2019 (COVID-19) utilizing CQDs are also highlighted. It can be envisaged that CQDs could further benefit the development of virus detectors and antiviral agents with added broad-spectrum activity and cost-effective production.

Antiviral Properties of Silver Nanoparticles against SARS-CoV-2: Effects of Surface Coating and Particle Size

Coronavirus disease 2019 (COVID-19) has spread rapidly and led to over 5 million deaths to date globally. Due to the successively emerging mutant strains, therapeutics and prevention against the causative virus, severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), are urgently needed. Prevention of SARS-CoV-2 infection in public and hospital areas is essential to reduce the frequency of infections. Silver nanoparticles (AgNPs) with virucidal effects have been reported. Therefore, we investigated the virucidal activity and safety of ten types of AgNPs with different surface modifications and particle sizes, in cells exposed to SARS-CoV-2 in vitro. The AgNPs could effectively inhibit the activity of SARS-CoV-2, and different surface modifications and particle sizes conferred different virucidal effects, of which 50-nm BPEI showed the strongest antiviral effect. We concluded that the efficacy of each type of AgNP type was positively correlated with the corresponding potential difference (R² = 0.82). These in vitro experimental data provide scientific support for the development of therapeutics against COVID-19, as well as a research basis for the development of broad-spectrum virucides. Given the increasing acquired resistance of pathogens against conventional chemical and antibody-based drugs, AgNPs may well be a possible solution for cutting off the route of transmission, either as an external material or a potential medicine.

Pathogen-Repellent Plastic Warp with Built-In Hierarchical Structuring Prevents the Contamination of Surfaces with Coronaviruses

Amidst the COVID-19 pandemic, it is evident that viral spread is mediated through several different transmission pathways. Reduction of these transmission pathways is urgently needed to control the spread of viruses between infected and susceptible individuals. Herein, we report the use of pathogen-repellent plastic wraps (RepelWrap) with engineered surface structures at multiple length scales (nanoscale to microscale) as a means of reducing the indirect contact transmission of viruses through fomites. To quantify viral repellency, we developed a touch-based viral quantification assay to mimic the interaction of a contaminated human touch with a surface through the modification of traditional viral quantification methods (viral plaque and TCID50 assays). These studies demonstrate that RepelWrap reduced contamination with an enveloped DNA virus as well as the human coronavirus 229E (HuCoV-229E) by more than 4 log 10 (>99.99%) compared to a standard commercially available polyethylene plastic wrap. In addition, RepelWrap maintained its repellent properties after repeated 300 touches and did not show an accumulation in viral titer after multiple contacts with contaminated surfaces, while increases were seen on other commonly used surfaces. These findings show the potential use of repellent surfaces in reducing viral contamination on surfaces, which could, in turn, reduce the surface-based spread and transmission.

Antiviral activity of algae biosynthesized silver and gold nanoparticles against Herps Simplex (HSV-1) virus in vitro using cell-line culture technique

As therapeutic antiviral agents, biological nanoparticles can fight the drug-resistant types of viruses helping the antiviral drug development. In this study, two blue-green algal strains; Oscillatoria sp. and Spirulina platensis were used, mediated by green Ag₂O|AgO-NPs and Au-NPs, respectively. For NPs characterization, the UV/Vis spectroscopy were used where their formation and crystallinity were proven with λ_max values for silver and gold NPs of 432 and 552 nm, respectively. The transmission electron microscope (TEM) X-ray diffraction showed a spherical-shaped Ag₂O|AgO-NPs (size; 14.42 to 48.97) while Au-NPs appeared with octahedral, pentagonal and triangular structures (size; 15.60-77.13 nm). The reducing, capping, and stabilization activities of algal polysaccharides and proteins were indicated via FTIR spectroscopy. Both Ag₂O|AgO-NPs and Au-NPs were investigated against Herpes Simplex virus (HSV-1) that has been indicated by its reduction activity of cytopathic effect (CPE). Cytotoxicity was evaluated on Vero cells and measured by MTT assay. Results showed a 90% reduction in CPE of HSV-1 applying Ag₂O|AgO-NPs, and Au-NPs at 31.25 μL., with a high reduction rate (49.23%) with Ag₂O|AgO-NPs than that of Au-NPs (42.75%). Current results proved the efficiency of green nanotechnology application with both Ag₂O|AgO-NPs, and Au-NPs as reducing and inhibitory agents for the HSV-1 replication.