key: cord-0838091-a4psk3mt
authors: Karthik, C.; Punnaivalavan, K. A.; Prabha, S. Pandi; Caroline, D. G.
title: Multifarious global flora fabricated phytosynthesis of silver nanoparticles: a green nanoweapon for antiviral approach including SARS-CoV-2
date: 2022-02-12
journal: Int Nano Lett
DOI: 10.1007/s40089-022-00367-z
sha: 2b84a300f7739aca7d7ace2ccbda18a3ace12702
doc_id: 838091
cord_uid: a4psk3mt

The progressive research into the nanoscale level upgrades the higher end modernized evolution with every field of science, engineering, and technology. Silver nanoparticles and their broader range of application from nanoelectronics to nano-drug delivery systems drive the futuristic direction of nanoengineering and technology in contemporary days. In this review, the green synthesis of silver nanoparticles is the cornerstone of interest over physical and chemical methods owing to its remarkable biocompatibility and idiosyncratic property engineering. The abundant primary and secondary plant metabolites collectively as multifarious phytochemicals which are more peculiar in the composition from root hair to aerial apex through various interspecies and intraspecies, capable of reduction, and capping with the synthesis of silver nanoparticles. Furthermore, the process by which intracellular, extracellular biological macromolecules of the microbiota reduce with the synthesis of silver nanoparticles from the precursor molecule is also discussed. Viruses are one of the predominant infectious agents that gets faster resistance to the antiviral therapies of traditional generations of medicine. We discuss the various stages of virus targeting of cells and viral target through drugs. Antiviral potential of silver nanoparticles against different classes and families of the past and their considerable candidate for up-to-the-minute need of complete addressing of the fulminant and opportunistic global pandemic of this millennium SARS-CoV2, illustrated through recent silver-based formulations under development and approval for countering the pandemic situation. GRAPHICAL ABSTRACT: [Image: see text]

'Nano' scale that refers to the one-billionth of a meter. Nanotechnology is a multi-disciplinary stream that emphasizes the purposeful design of manipulation of matter at the scale of atomic level utilizing the existing approaches, techniques, and types of equipment available with conventional and modern science and engineering. Nanoparticles do focus on particles that exist in the range of 1-100 nm [1] . Enhancement or acquisition of new characteristics at the nanoscale level compared to the bulk properties gained more interest with research on this avenue within the past 2 decades. Higher ratio of surface area to volume at the nanoscale level and the shift in the laws of physics at the nanometric level are the two important attributes that contribute to effective catalytic activity to various multi-disciplinary applications [2] .

Approaches of nanoparticle synthesis include a top-down (TD) approach that encompasses the disintegrative breakdown of bulk materials into finer grain sizes of nanoscale. Synthesis methods such as mechanical milling, laser ablation, and sputtering follow the TD approach. The alternative approach of synthesis encloses gradual consecutive integration of atoms/molecules at various smaller scales that leads to the 'nucleation' site formation followed by agglomeration around the nucleation site engenders nanoparticle formation. Spray pyrolysis, sol-gel method & green synthesis methods, etc. are some of the BU routebased nanoparticle synthesis approaches [3] .

Various methods for the synthesis of nanoparticles include physical, chemical, and biological methods with their own pros and cons for each. Physical methods utilize higher mechanical energy, high radiation, high temperature, and greater sized apparatus for the synthesis. Grain size control and less manual power are remarkable advantages, whereas parameter optimization and toxicity are notable demerits. Chemical methods involve the usage of chemical reducing and capping agents of organic and inorganic species; sometimes, the same reagents being both. Simple to process and control over scale-up are highlightable merits, whereas environmental unfriendly, lesser biocompatibility are notable demerits. To address the backlogs of physical and chemical methods, shift to biological methods of synthesis enters the research avenue. Environment-friendly, no application of higher temperature, pressure, heat, energy, most supporting biocompatibility, devoid of toxic chemicals, easier handling, and scale-up are all that makes biological synthesis more fascinating than any other [3] [4] [5] . Preference of water over any other organic solvents as the major solvent and thereby the greater colloidal stability attainment of the nanoparticle product is the unique property on green synthesis and the fact that water is the most biocompatible solvent is found to be reflected with the application part [6] .

Among the widely explored metallic nanoparticles, silver nanoparticles (AgNPs) have the continuity of being used for centuries in human civilizational history due to their very unique and specific physical, biological, electronic, catalytic, surface, and chemical properties. The strongest biocidal properties against biota of microbial range from bacteria, viruses, fungi, algae to higher nematodes, and helminths. It also possesses non-toxicity toward animal cells and compatibility to human cell lines provides numerous biological product applications. Colloidal stability of AgNPs makes them suitable as preservatives in cosmetics and medicated products, optical plasma-resonance scattering property makes a bio-labeling candidate and sensor, imaging applications, anti-inflammation property-driven wound-healing engineering, surface coating property enhanced paints, reusable catalytic property over the degradation of different classes of dyes, anti-thrombogenic and hemodynamic properties utilized cardiac valves and stents, implants with anti-platelet property and stimulation of vascular endothelial growth factor (VEGF) that promotes angiogenesis, the process of new blood vessel formation and endothelial vasodilation property-driven anti-hypertensive implant, peculiar AgNPs mechanical properties such as elastic modulus and flexural strength improvising of acrylic resin-based removable dental dentures against opportunistic oral pathogens, anti-adhesion and anti-infective property-driven orthodontic brackets against dental caries, metabolonomics intervention and perturbation property with nucleotides, photosynthesis and photorespiration processes, anti-microbial properties, anti-static properties, electrically conducting, and most importantly self-cleaning property. Electro-conductive fibers help to protect from radiation emitted by electronics. Selfcleaning property resists the deepening of stains and dirt from the point of incidence. Nano-functional fibers are used to produce odor-free undergarments, socks and stockings and research over the face masks coated with silver nanoparticles used during the COVID-19 pandemic is contemporary anti-microbial property example [7] [8] [9] [10] [11] [12] [13] [14] [15] [16] [17] [18] [19] [20] .

These AgNPs shall be synthesized through various routes out of which biological routes again gain importance due to aforesaid attributes of the produced nanoparticles. The biological route shall be further taken as phyto-mediated, microbe-mediated, and other molecular templates of broader category-inorganic, organic, metals, polysaccharides, proteins & miscellaneous chemical reagents, etc. [21] .

Phyto-mediated synthesis of nanoparticles has its own spectrum of source that includes extracts of leaves [22, 23] , bark [24, 25] , stem [26, 27] , latex [28, 29] , fruit [23, 30, 31] , flower [32] [33] [34] [35] , root [36] [37] [38] , seed [39, 40] , and tuber [41, 42] . Different parts of the different plants have their own varying concentration of reductase enzyme that reduces the metal nitrate solution into the nanosized metal particles. Plenty of systems with single reducing agents, dual-reducing agents exist, whereas also a single source of an enzyme that also catalyzes hybrid formation and directs to nanocomposite hybrid system exists [43] .

Leaves are rich source of a larger number of phytochemicals that includes tannins, flavonoids, saponins, alkaloids [ 

Stem, bark, and latex of the plants are also utilized as the source of nanoparticle synthesis and its composition ranges with a wide number of constituents alkaloids, flavonoids, tannins, saponins, cardiac glycosides, glycosides, proteins, carbohydrates, steroids, reducing sugars, anthracene glycosides, resins, triterpenes, procyanadines, anthraquinone [161] [162] [163] [164] [165] , fraxidin, fraxetin, scoparone, 3-acetylaleuritolic acid, beta-sitosterol, and sitosterone [166] , etc. were the actual secondary metabolites of various biochemical cycles and some are growth steroids that assist in the regulation of growth and development of the plant assists phyto (stem, bark, and latex)-mediated nanoparticle synthesis. Gums and resins from bark, stem, and latex are also used for NP synthesis. Table 2 is the list with representative examples of stem, bark, and latex used for the synthesis of silver nanoparticles.

Fruits are another phyto-source of nanoparticle synthesis. Peels, pulps, and complete fruit can be used for reduction. Usually, they have polyphenols, minerals, vitamins-tocopherols and organic acids (linoleic acid, ascorbic acid, citric acid, etc.), triterpenoids, tannins, carotenoids, phenolics, and flavonoids (rutin, myricetin, luteolin, quercetin, apigenin, and kaempferol). Constituents include moisture, sugars (sucrose, fructose, and glucose), protein, fatty acid [total saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), and polyunsaturated fatty acids (PUFA)], ash contents, and energy contents [186] [187] [188] . The same constituents which are metabolic precursors and building blocks of the fruit cell wall that correspond to the texture of the fruit are found to a huge extent in seeds extracts of the fruits in addition to steroids [189] . Table 3 is the list with representative examples of fruits used for synthesis of silver nanoparticles.

Phyto-constituents of flower extracts are found to contain flavonoids, tannins, phlobatannins, cardiac glycosides, alkaloids and triterpenes, saponins, anthraquinone, phenol, protein and amino acids, carbohydrates, oil, fats & resins, coumarine, phytosterol, gums, and mucilages [219-223]. Table 4 is the list with representative examples of flowers used for synthesis of silver nanoparticles. concentrations corresponding to the needs of that particular species. Saponins, tannins, triterpenoids glycosides, and alkaloids are also present in the seeds [261] . Table 6 shows the list with representative examples of seeds used for synthesis of silver nanoparticles.

Microbes and metal interaction were greatly explored already in the discipline of environmental biotechnology through bioremediation, biomineralization, and bioleaching. Microbe-mediated synthesis of metallic nanoparticles (MNPs) includes prokaryotic bacteria, eukaryotic fungi, and some viral particles that in turn takes place either intracellular or extracellular. Interaction of positive metal ions in the solution with the negatively charged cell wall facilitates the transportation of ions to intracellular space and further reduction by the cellular enzyme system produces metallic nanoparticles which shall further diffuse out of the cell is the mechanism of intracellular microbemediated green synthesis of MNPs. Experiments that tend to chemical treatment of cell wall charge alteration show more favorable NP synthesis that proves the interaction of cell wall charge and cellular transportation in this process. The alternate synthesis mechanism includes nitratereductase enzymes of the microbes that reduce the metal ions extracellularly [276] . Tables 7, 8, and 9 show the list with representative examples of bacteria, fungi, and algae used for synthesis of silver nanoparticles.

Apart from the phyto-mediated and microbe-mediated routes, the macromolecules such as carbohydrates, organic [160] acids, proteins, and other miscellaneous chemicals are also used in the reduction and capping of silver nanoparticles. Table 10 gives the list with representative examples of macromolecules that have been employed as reducing agents for silver nanoparticle synthesis.

Silver has always been widely preferred to treat various diseases; it is used as an antiseptic and anti-microbial against Gram-positive and Gram-negative bacteria. Although the highly antibacterial effect of AgNPs has been widely described, silver-based nanocomposites also have gained more attention in many different areas, including antibacterial applications. Generally, the nanocomposite material supports the extended release of silver nanoparticles by adhering to either large-sized or small-sized surface of support materials and thereby increases the anti-microbial activity [364] . The interaction of NPs with polymers not only makes the nanoparticles more compatible with polymer matrix, but also change their properties. The use of polymers in functionalization provides a large surface area and mechanical strength of nanoparticles, which transfers into increased durability and extended use. Moreover, it limits unintended release of nanoparticles into the environment and thereby preventing its loss and aggregation. Among the support materials investigated (Table 11) , small-sized SiO 2 NPs are cheap and release high quantity of AgNps per unit volume [365] .

Viruses are the minuscule obligate microbes that infect all form of lives ranging from bacterial pathogens to humans where generation of energy, synthesis and assembly of replication, and other factors for central dogma take place within the host making avail of the host cell machineries for the above process. The gene core material shall be either single or double stranded, ribonucleic acid (RNA), or deoxy-ribo nucleic acid (DNA) encapsulated with proteins made the layer of capsomeric subunits assembly to form either helical or spherical sphere [381] . Infection of viruses has unique stages in the process of viral replication into the host cell starting with attachment to host cell, accumulation of viral load and penetration, the release of viral nucleic acid, processing of nucleic acid as replicative template form and its entry into the host cell nucleus, viral genome replication, transcription and translation of the replicated viral nucleic acid, assembly and release of virions, attachment to the closer proximal cells, and repetition of the cycle [382] . Therapeutic targeting shall be with any one of the above steps and sometimes combinatorial drug targeting two or more steps of the viral load increase. Targeting component shall be fusion inhibitors, channel blocking compounds, transcription blocking compounds, nucleotide polymerase inhibitor, reverse transcriptase and helicase inhibitors, protease and virion assembly inhibitors, neuraminidase inhibitors, and combination from any of the above [383] .

Silver nanoparticles have efficacious anti-microbial properties, which have been taken advantage of for addressing the evolving hyper virulence spikes of different families of viruses during different times. Silver nanoparticles with its exceptional surface area and binding properties exhibit antiviral attributes through interaction either at the binding stage of virus with the host cell (viral entry inhibition) or interference with the viral genome expression cycle inside the cell (virucidal). The out of the ordinary porosity property of silver nanoparticles facilitates the movement and interaction of different other smaller molecules and particles with the viral factor and cellular factors of the viral genome [384, 385] .

Silver nanoparticles have a different mechanism of action and activity against viruses such as the affinity of binding to glycoprotein-120, strong competitive binding of cell attachment with the viral strain, interference and inhibitory blocking of viral binding and penetration, viral DNA interaction and inactivation of the viral strain before entry into the host cell, etc. The mechanism for antiviral property of silver metallic nanoparticles with respect to virus entry inhibition includes interaction of metal ions with the host cell-binding surface glycoproteins of the virus and inhibition of the host-virus physical attachment. The denaturation of the protein coat of the virus by irreversible modification of the integrity of the coat frame through reduction of the disulfide bonds and hence diminish the infectivity of the viral residues. The silver nanoparticles are capable of targeting the genetic material of the virus irrespective of the nature of genetic material (DNA, RNA) and their type of strand (single, double). Due to their natural affinity with the phosphate groups of the nucleic acid interacts with the disassembled viral nucleic acid and cellular replication factors thereby preventing the viral replication and or propagation 10-20 Spherical [260] taking place within the host cell and hence block further progeny or virion expression [384] [385] [386] [387] [388] [389] [390] .

Silver nanoparticles possess a diverse extent of interactive mechanism with every family and classes of virus. Human immunodeficiency virus (HIV), herpes virus, influenza virus, coxsackie, and dengue virus including a range of enveloped, non-enveloped viruses to RNA-and DNA-based virus titer against varying concentrations of silver nanoparticles were studied, and with fold reduction virucidal activity against all the viral classes, the enveloped and positive sense RNA viruses have greater reduction than non-enveloped and negative sense RNA viruses [391, 392] .

Lara et al. substantiated the activity of silver nanoparticles against HIV in both the cell-free and cell-associated forms, and found to reduce many fold of the viral gp-120 interaction, accumulative fusion, and virulent factor infectivity with the CD-4 cell receptor of the host cell. With the interaction hypothesis, the AgNPs also tends to denature and weaken the disulfide regions of CD-4-binding domain present in the gp-120 of the viral cell-surface receptor which was reflected with the multi-fold reduced fusion and infectivity making it a suitable candidate for early stage and postentry target [385] .

The novel SARS-CoV2, a member of the family of coronaviridae being the enveloped, single-stranded RNA virus shall be tackled and targeted using silver nanoparticle on the basis of previous works done against epidemic and pandemic of the long past to later past that includes H5N1, and also graphene-based silver nanocomposite contributes for absolute suppression of the disease against sun hemp rosetta virus [SHRV] in the plant culture system as potted plants exposed to the viral load sprayed [287, 393, 394] . Feline coronavirus (FCoV) and infectious bursal disease virus (IBDV) were systematically targeted using graphene oxide-silver nanocomposite and the inhibition route were found to be hydrophobic and electrostatic interaction between the aromatic GO plane and lipids. Dipolar bonds between thiol residues and Ag + ions were another assisting inhibitory route. For non-enveloped viruses, there will be the absence of the hydrophobic interaction, thereby the stronger dipolar (coordinate covalent) bond directs the extent of inhibition [395] . Other composites of silver nanoparticles includes tannic acid, poly vinyl chloride, chitosan as second constituent along with silver that were acted against herpes simplex virus type 2 (HSV-2), human immunodeficiency virus, and H1N1 influenza virus, respectively, follows interference with attachment, membrane receptor channel binding and interaction with the genetic material of the virus upon uncoating [396] .

Different results show that the AgNPs' interaction with gp-120 was found to be size dependent and nanoparticles of 1-10 nm size were able to bind with extra-ordinary activity of inhibition and also involved with reduction of reverse transcription inhibition, so that the transformation of the viral RNA into cDNA gets inhibited and thus the viral load replicative steps and infectivity [397] . Respiratory syncytial infections of viral origin are a peril to humankind by making the infected individuals vulnerable to other range of infections, i.e., serving as a comorbidity to different other diseases. Silver nanoparticles and also its composite exploration as an antiviral agent to such respiratory infections are promising with past to recent present. Silver nanoparticles reduced using ascorbic acid with different weight percentages, capping of graphene oxide (GO) over the silver nanospheres, and silver nanoparticles bound to thiol-group functionalized GO were tested in vivo against coronavirus OC43 and Influenza A virus resulted with mild infectivity inhibition under certain conditions in ascorbic acid reduced AgNP and inhibition only at undiluted level in thiolated samples. Rapid viability and infectivity reduction in intact GO-capped Ag nanospheres observed were promoted by stabilization of bonds with steric hindrance of the composite. Interestingly, the plaque forming ability inhibition of the viruses was found with undiluted (100% concentrated) to diluted to 1% concentration of GO-capped-Ag-nanospheres as there is a synergistic effect between GO-AgNP against enveloped viruses that is independent of carrier solvent in the experiment. Five minute treatment to the viral load in prior infecting to the cell lines rapidly reduces the infectivity. Similar synergistic effect was also observed with the AgNPs-chitosan composites which is higher than the individual activities of them against the infection. Various assays that are useful to find the antiviral activity of the silver nanoparticles include proliferation assay, plaque forming unit assay, cell viability assay, real-time quantification polymerase chain reaction, western blot, cytotoxicity assays and pseudo virus entry assay, indirect immuno fluorescent assay, etc. [398] [399] [400] [401] .

Silver nanoparticles with their incredible antiviral attributes on monosystem also possess the property of agglomeration due to their tremendous surface energy when present as a single entity in the colloidal solution. Once after the agglomeration the increased grain size diminishes the properties of silver nanoparticles, i.e., reduced stability and activity. Various methodologies have been developed to address the agglomeration of colloidal AgNPs through the process of capping from green components to different inert molecules. The capping agent usually interacts with the external surface of the mono-nanoparticles and thereby reduces the aggregation. Polymers, inert macromolecules, resins and gums, plant extracts, and other capping agents influence the steric and electrostatic stabilization and enhance the activity. The following table (Table 12) comprises representative examples of capping agents with silver nanoparticles and their mode of action against various families of virus [402] [403] [404] [405] .

Silver nanoparticles have their application in a very broader spectrum among which the latest utilization is against the destructive core global pandemic of this millennium, novel coronavirus, severe acute respiratory syndrome-coronavirus 2 (SARS-CoV2), the seventh coronavirus till date from the first virus identified in 1960, which is the one with highest infectivity rate and the fatality rate among the others from the same class [401] . Coronavirinae the subfamily of coronaviridae viral family which is been composed of four genera of viruses such as α-genera, β-genera, γ-genera, and δ-genera among which the alpha and beta genera are so far reported to be infectious to highly infectious against humans, whereas the gamma and delta are targeted to avian species. Around 79% of the similarity with gene sequence of SARS-CoV2 are conserved with SARS-CoV reported earlier and 50% identical sequence with middle-east respiratory syndrome related coronavirus (MERS-CoV). The MERS and SARS-CoV2 binding to cell surface is a remarkable feature of difference among which earlier one binds to dipeptidyl peptidase receptor-4 and the later one to angiotensin-converting enzyme-2 receptor. Such unique non-conserved region and properties make the novel SARS-CoV2 more infectious than any other coronaviridae viruses and thus given the name 'novel' coronavirus [414] [415] [416] [417] .

One among the promising candidatures for the preventive recommendations, treatment has unique position for AgNPs. As AgNPs have been previously reported counter activity against wide spectrum of pneumonia-like zoonotic, acute respiratory viruses, they shall be utilized along the drugs or therapy in combination as well as the single bioactive compound with the therapeutic compound.

The exact sequential mechanism of virus and AgNP interaction have different conceptual hypothesis (Fig. 1 ) from mimicking as cell-surface receptor to innate immunity activation. Intervention with cell-surface receptor binding and thereby inhibiting the attachment of the virus to the ACE receptor cells. By the attachment of AgNPs to the viral genome inhibits the viral replication inside the host like paramyxoviridae viruses, influenza viruses, retroviridae viruses, and hepatitis B virus. The pH of airway epithelium might become more acidic due the decrease in pH by the release of silver ions, which makes the environment more difficult for the virus to sustain. Ag + ions have the ability to interact and inhibit the respiratory enzymes of the virus and their potential interference with the viral nucleic acid was already demonstrated against wider spectrum of viruses in the past [394, 396, 418] . The In vitro study on Vero E6 cells infected with a fixed amount of SARS-CoV-2 virus revealed that the [400] . In another In vitro study on SARS-CoV-2 infection in cultured cells showed that a reduction of about 80% cells at a concentration of 0.03% [419] . Nanoparticle composite hybrids of silver, zinc, and copper exhibited vast antiviral property against HIV and other similar enveloped viruses. Capped silver nanoparticles are found to inhibit the negative riboxy nucleic acid strand synthesis of PEDV, another member of the corona virus family. Moreover, the innate immune response induction by the nanocomposites focuses on elimination of the probability of viral progeny development [420] .

A provisional patent filed formulation of Quickgun Lifesciences, India has cepharanthine (CEP), a potent inhibitor drug against the virus in screening, loaded in combinatorial with biosilver. This CEP-biosilver oral spray formulation is about to direct a double-targeting of glycoproteins present in the pathogenic virus among which the phytoderived inhibitor CEP inhibits the replication through targeting the corona virus glycoprotein and AgNPs usually targets the glycoprotein knobs of viruses. In PEGylated form as dry powder, the silver nanoparticles are formulated to deliver in either single dose or multiple dose inhalers. With further research, this drug therapy shall be proven and considered as a potentially safe drug, as AgNPs are with extra-ordinary biocompatible characteristics, but are cytotoxic and apoptotic to cancer and other abnormal cells [421] . Imbed biosciences Inc., a Madison, Wisconsin-based pain killer and wound-healing formulation firm, is working on the integration of the pre-approved microlyte matrix wound-healing complex with the antiviral silver nanoparticles. They are bound with the viral particles and found to interact and freeze the mechanism through which viral particles and human cells interact. In a preliminary research carried out by the Virology Research Institute, London, the AgNPs synthesized by the company, is found to be either -cidic (kill) or -static (inactivate) with 99.9% of the SARS-CoV2. These controlled lab results are really hopeful to take on into the preliminary clinical trials and follow-of-human trials. The product is planned to be delivered in a nasal spray formulation once it clears the levels of pharmaceutical trials [422] .

A consortium of companies that include ApIfilm, Braskem, Nanox, and the UFSCar (Brazil) and Jaume I of Castellón (Spain) universities developed and licensed technology of PVC polymer films used in food packaging, coated with silver and silica nanoparticles, is successfully found to inactivate the novel coronavirus. Different time bound direct exposure of novel SARS-CoV2 virus upon the film was carried out and after which the viral particles were made to infect African monkey kidney cell lines, called as vero cells. The infection, virulence and replication rate before and after exposure to films and films without silver and silica coatings were carried out and comparison studies were done. The amplification of viral materials by PCR shows about 99.84% and almost 100% reduction in the viral genetic materials, after exposure time of 2 and 15 min, respectively. A highly satisfactory performance of stretch-wrap wrapping material for perishable food and other grocery items is more about to explore and the exact mechanism studies shall open up more avenues of improvised strategies to tackle the novel SARS-CoV2 [423] .

Recent research includes incorporative application of the AgNPs' coating and dispersion in train cargos, air filters, handles of subways, handrails of elevators and to surgical face masks, medical devices like personal protection equipment kits, and the list of consumables extends.

Several advantages of utilizing AgNPs as candidature to SARS-CoV2 newer virus variants with faster clinical trials than usual include greater probability of effective virucidal properties to similar respiratory syncytial disease causing viruses, rapid activation of the host's innate immunity response and cascade system, greater stability, biocompatibility and easy to control over coating process, diverse choice of conjugation and hybrid therapy as they are encapsulated nanocarrier themselves, synergistic property with improved efficacy and reduced level of resistance, and availability of valid, standard, optimized, controlled, and commendable property engineering technologies [424] [425] [426] .

Concerns range from availability of nanoparticle precursor, activity variation with respect to the source of nanoparticle synthesized, non-optimized and unstandardized procedure of surface coatings, pharmacodynamics and pharmacokinetic studies of the antiviral candidatures, and no application restrictions framework-MRI exposure to metallic nanoparticle-coated mask leads to face burn that WHO advised lately. Lack of a proper standard disposal protocol of silver incorporated products shall be an eco-system pressure created on the natural microbiota of the environment [400] . The selection of the capping agent that provides prolonged stability to the silver nanoparticles coating from a wide range of such preceding successful components should be appropriately chosen with the trials. However, eventual addressing of all such cons and standardizing the protocols for prolonged activity retainment on the coated surfaces shall take the integrated research to tackle SARS-CoV2 for the very next level.

Silver nanoparticles, the prominent aspiring and promising candidate against the multitude of applications, have been narrowed toward its antiviral spectra attributes with the review. Green synthesis of silver nanoparticles through phyto-mediated route is found to be more promising due to its simplicity of conduction and presence of versatile natural plant-based compounds such as polyphenols to alkaloids, etc., provides the combined arena for synthesis that covers nanoparticles of varying sizes and morphologies as the outcome. Tailoring and scale-up of the plant-mediated route has a higher edge and ease of convenience compared to the microbe-mediated and other macromolecule-mediated methods of synthesis.

Silver nanoparticles' activity against the virus is dependent on various factors such as the size and concentration of the nanoparticles, enveloped and non-enveloped coat of virus, nature of genetic material (DNA /RNA), sensing of strand (positive/negative sense strands), agglomeration, etc. Binding with the glycoproteins to formation of affinity interactions and denaturation of the bonds of viral surface, there are conglomerated routes through which the inactivation and the disintegration of viral strain takes place at different targeting points such as during entry and post-entry.

Several SARS-CoV2 formulations utilize silver as a core targeting compound or with combinatorial drugs as hybrids. The proven antiviral property strongly suggests the usage of silver nanoparticles with appropriate capping agent coatings and also with composites in surface sterilization to therapeutic targeting. A newer avenue of being a composite component of targeted drug delivery system emulsions to being the core component of drug composite, multiple actions of silver nanoparticles against existing and still evolving viruses would be a more fascinating research and development area of the near to far future.

Funding This research received no specific grant from any funding agency in the public, commercial, or not-for-profit sectors. 

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Green synthesis, characterization and evaluation of biocompatibility of silver nanoparticles

Green synthesis and characterization of polymer-stabilized silver nanoparticles

Size-controlled green synthesis of silver nanoparticles mediated by gum ghatti (Anogeissus latifolia) and its biological activity

Green synthesis of colloidal silver nanoparticles using natural rubber latex extracted from Hevea brasiliensis

Green synthesis of silver nanoparticles using latex of Jatropha curcas

Green synthesis of silver nanoparticles, decorated on graphene oxide nanosheets and their catalytic activity

Green synthesis of silver nanoparticles using Pinus eldarica bark extract

Green synthesis of silver nanoparticles using Prosopis juliflora bark extract: reaction optimization, antimicrobial and catalytic activities

Green synthesis of silver nanoparticles using Salacia chinensis: characterization and its antibacterial activity

Green synthesis of silver nanoparticles using Salvadora persica L. and its antibacterial activity

In situ green synthesis of silver nanoparticles on cotton fabric using Seidlitzia rosmarinus ashes

Green synthesis of silver nanoparticles using Terminalia cuneata and its catalytic action in reduction of direct yellow-12 dye

Green synthesis of silver nanoparticles using latex extract of Thevetia peruviana: a novel approach towards poisonous plant utilization

Strawberry-tree, blackthorn and rose fruits: detailed characterisation in nutrients and phytochemicals with antioxidant properties

Identification and assessment of antioxidant capacity of phytochemicals from kiwi fruits

Phytochemicals and antioxidant activity of different fruit fractions (peel., pulp., aril and seed) of Thai gac (Momordica cochinchinensis Spreng)

preliminary phytochemical screening of various extracts of punica granatum peel: whole fruit and seeds

Green synthesis of silver nanoparticles using apple extract and its antibacterial properties

Green synthesis of gold and silver nanoparticles using Averrhoa bilimbi fruit extract

Green synthesis and characterization of silver nanoparticles using banana peel extract and their antimicrobial activity against representative microorganisms

Green synthesis of silver nanoparticles by using stem derived callus extract of bitter apple (Citrullus colocynthis)

Green synthesis of silver nanoparticles using aqueous rinds extract of Brucea javanica (L.) Merr at ambient temperature

Capuli cherry-mediated green synthesis of silver nanoparticles under white solar and blue LED light

Green synthesis and characterization of silver nanoparticles using Citrullus lanatus fruit rind extract

Green synthesis of silver nanoparticles mediated by Coccinia grandis and Phyllanthus emblica: a comparative comprehension

Coconut water assisted green synthesis of silver nanoparticles

Green synthesis of silver nanoparticles using Cordia dichotoma fruit extract and its enhanced antibacterial, anti-biofilm and photo catalytic activity

Plant mediated green synthesis and antibacterial activity of silver nanoparticles using Crataegus douglasii fruit extract

A novel 'green'synthesis of colloidal silver nanoparticles (SNP) using Dillenia indica fruit extract

Plant mediated green synthesis and antibacterial activity of silver nanoparticles using Emblica officinalis fruit extract

Green synthesis, characterization and anti-inflammatory activity of silver nanoparticles using European black elderberry fruits extract

Low-cost and eco-friendly green synthesis of silver nanoparticles using Feronia elephantum (Rutaceae) against Culex quinquefasciatus, Anopheles stephensi, and Aedes aegypti (Diptera: Culicidae)

A novel green synthesis of silver nanoparticles and their catalytic action in reduction of Methylene Blue dye

Green synthesis of water-dispersible silver nanoparticles at room temperature using green carambola (star fruit) extract

Green synthesis of silver monometallic and copper-silver bimetallic nanoparticles using Kigelia africana fruit extract and evaluation of their antimicrobial activities

Green synthesis of silver nanoparticles and their application for the development of optical fiber based hydrogen peroxide sensor

Green synthesis of silver nanoparticles using fruit extract of Malus domestica and study of its antimicrobial activity

Green synthesis of silver nanoparticles using extract of oak fruit hull (Jaft): synthesis and in vitro cytotoxic effect on MCF-7 cells

Microwave-assisted green synthesis of silver nanoparticles using orange peel extract

Rapid green synthesis of silver and gold nanoparticles using peels of Punica granatum

Pine cone-mediated green synthesis of silver nanoparticles and their antibacterial activity against agricultural pathogens

Green synthesis of silver nanoparticles through reduction with solanum xanthocarpum l berry extract: characterization, antimicrobial and urease inhibitory activities against helicobacter pylori

Green synthesis of Ag nanoparticles using Tamarind fruit extract for the antibacterial studies

Green synthesis of silver nanoparticles using Terminalia chebula extract at room temperature and their antimicrobial studies

Cinnamon zeylanicum bark extract and powder mediated green synthesis of nano-crystalline silver particles and its bactericidal activity

Green synthesis of silver nanoparticles using aqueous extract of saffron (Crocus sativus L.) wastages and its antibacterial activity against six bacteria

Green synthesis and characterization of silver nanoparticles using fritillaria flower extract and their antibacterial activity against some human pathogens

Murraya koenigii leaf-assisted rapid green synthesis of silver and gold nanoparticles

Green synthesis of silver nanoparticles from the extract of the inflorescence of Cocos nucifera (Family: Arecaceae) for enhanced antibacterial activity

Green synthesis of silver nanoparticles from marigold flower and its synergistic antimicrobial potential

Green synthesis and characterization of silver nanoparticles using alcoholic flower extract of Nyctanthes arbortristis and in vitro investigation of their antibacterial and cytotoxic activities

Rapid green synthesis of silver nanoparticles and nanorods using Piper nigrum extract

Rapid synthesis of biocompatible silver nanoparticles using aqueous extract of Rosa damascena petals and evaluation of their anticancer activity. Asian Pac

One step green synthesis of silver nano/microparticles using extracts of Trachyspermum ammi and Papaver somniferum

Effect of operational parameters, characterization and antibacterial studies of green synthesis of silver nanoparticles using Tithonia diversifolia

Phytochemical analysis of methanolic extract of roots of kalanchoe pinnata by HPLC and GCMS

Phytochemical screening and antibacterial evaluation of the leaf and root extracts of Cassia alata Linn. Afr

Antimicrobial, antioxidant, anti-inflammatory activities and phytoconstituents of extracts from the roots of Dissotis thollonii Cogn (Melastomataceae)

Scientific validation of the antimicrobial and antiproliferative potential of Berberis aristata DC root bark, its phytoconstituents and their biosafety

Facile green synthesis of silver nanoparticles using Berberis vulgaris leaf and root aqueous extract and its antibacterial activity

Antibacterial and catalytic activities of green synthesized silver nanoparticles

Green synthesis of silver nanoparticles using root extracts of Cassia toral L. and its antimicrobial activities

Green synthesis of gold and silver nanoparticles using aqueous extract of Cibotium barometz root

Green biosynthesis of silver nanoparticles using callicarpa maingayi stem bark extraction

Green synthesis of silver nanoparticles using Delphinium denudatum root extract exhibits antibacterial and mosquito larvicidal activities

Green synthesis of silver nanoparticles using methanolic root extracts of Diospyros paniculata and their antimicrobial activities

Green synthesis, characterization and antimicrobial activity of silver nanoparticles using methanolic root extracts of Diospyros sylvatica

Sunlight based irradiation strategy for rapid green synthesis of highly stable silver nanoparticles using aqueous garlic (Allium sativum) extract and their antibacterial potential

Green synthesis of robust

Novel green synthesis and characterization of the antioxidant activity of silver nanoparticles prepared from nepeta leucophylla root extract

Green synthesis of silver nanoparticles and its application for mosquito control

Rapid green synthesis of silver nanoparticles from silver nitrate by a homeopathic mother tincture phytolacca decandra

Green synthesis of silver nanoparticles using Rheum palmatum root extract and their antibacterial activity against Staphylococcus aureus and Pseudomonas aeruginosa

Bioreduction potentials of dried root of Zingiber officinale for a simple green synthesis of silver nanoparticles: antibacterial studies

Green synthesis of silver and gold nanoparticles using Zingiber officinale root extract and antibacterial activity of silver nanoparticles against food pathogens

Watermelon seeds as food: Nutrient composition, phytochemicals and antioxidant activity

Green synthesis of silver nanoparticles using Artocarpus heterophyllus Lam seed extract and its antibacterial activity

Green synthesis of silver nanoparticles from seed extract of Brassica nigra and its antibacterial activity

Green synthesis of silver nanoparticles using Coffea arabica seed extract and its antibacterial activity

Green synthesis of spherical silver nanoparticles using Ducrosia anethifolia aqueous extract and its antibacterial activity

In vitro antioxidant, antimicrobial, cytotoxic potential of gold and silver nanoparticles prepared using Embelia ribes

Green synthesis of silver nanoparticles using grape seed extract and their application for reductive catalysis of direct orange 26

Green synthesis of silver nanoparticles using seed extract of Jatropha curcas

Green synthesis of silver nanoparticles using Macrotyloma uniflorum

Rapid green synthesis of silver nanoparticles by aqueous extract of seeds of nyctanthes arbor-tristis

Facile green synthesis of silver nanoparticles using seed aqueous extract of Pistacia atlantica and its antibacterial activity

Green synthesis of silver nanoparticles from ethanolic seed extract of Acranythes aspera (Linn) and its antiinflammatory activities

Plantmediated green synthesis of silver nanoparticles using Trifolium resupinatum seed exudate and their antifungal efficacy on Neofusicoccum parvum and Rhizoctonia solani

Green synthesis of silver nanoparticles from Tectona grandis seeds extract: characterization and mechanism of antimicrobial action on different microorganisms

Synthesis of silver nanoparticles using seed exudates of Sinapis arvensis as a novel bioresource, and evaluation of their antifungal activity bioresour

Biological synthesis of metallic nanoparticles: plants, animals and microbial aspects

Facilely green synthesis of silver nanoparticles into bacterial cellulose

Green biosynthesis of silver nanoparticles from an actinobacteria Rhodococcus sp

Green synthesis of silver nanoparticles using cell extracts of Anabaena doliolum and screening of its antibacterial and antitumor activity

Synthesis of silver nanoparticles by solar irradiation of cellfree Bacillus amyloliquefaciens extracts and AgNO3. Bioresour

Green synthesis of silver nanoparticles by Bacillus methylotrophicus, and their antimicrobial activity

Green synthesis of silver nanoparticles using keratinase obtained from a strain of Bacillus safensis LAU 13

Comparative study on the biosynthesis and characterization of silver nanoparticles by E. coli using LB and M9 media and their anitimicrobial application

Green synthesis of anisotropic silver nanoparticles and its potential cytotoxicity in human breast cancer cells (MCF-7)

Valorization of mutant Bacillus licheniformis M09 supernatant for green synthesis of silver nanoparticles: photocatalytic dye degradation, antibacterial activity, and cytotoxicity

Intra/extracellular biosynthesis of silver nanoparticles by an autochthonous strain of proteus mirabilis isolated fromphotographic waste

Green synthesis of silver nanoparticles and their application in plant virus inhibition

Green synthesis of silver nanoparticles by microorganism using organic pollutant: its antimicrobial and catalytic application

Green synthesis of silver nanoparticles using marine-derived fungus Aspergillus niger. Micro

Fungus-mediated green synthesis of silver nanoparticles using Aspergillus terreus

Carnivorous plants used for green synthesis of silver nanoparticles with broad-spectrum antimicrobial activity

Green synthesis of silver nanoparticles by a novel method: comparative study of their properties

Fusarium solani: a novel biological agent for the extracellular synthesis of silver nanoparticles

Green synthesis of protein capped silver nanoparticles from phytopathogenic fungus macrophomina phaseolina (Tassi) Goid with antimicrobial properties against multidrug-resistant bacteria

Myco-synthesis of silver nanoparticles using Metarhizium anisopliae against the rural malaria vector Anopheles culicifacies giles (diptera: culicidae)

Green synthesis of silver nanoparticles using the mushroom fungus schizophyllum commune and its biomedical applications

Green synthesis of silver nanoparticles induced by the fungus penicillium citrinum

Complete green synthesis of silver-nanoparticles applying seed-borne penicillium duclauxii

Green synthesis of silver nanoparticle by penicillium purpurogenum NPMF: the process and optimization

Green synthesis of silver nanoparticles by phoma glomerata

Process optimization for green synthesis of silver nanoparticles by sclerotinia sclerotiorum MTCC 8785 and evaluation of its antibacterial properties

Green synthesis of silver nanoparticles by Trichoderma harzianum and their bio-efficacy evaluation against Staphylococcus aureus and klebsiella pneumonia

Antimicrobial activity and green synthesis of silver nanoparticles using trichoderma viride

Intracellular and extracellular green synthesis of silver nanoparticles using desmodesmus sp: their antibacterial and antifungal effects

Green synthesis of silver nanoparticles using marine algae caulerpa racemosa and their antibacterial activity against some human pathogens

Green synthesis of silver nanoparticles using marine macroalga chaetomorpha linum

Green synthesis of silver nanoparticles: characterization and determination of antibacterial potency

Green synthesis of silver nanoparticles using polysaccharides extracted from marine macro algae

Green synthesis of silver nanoparticles using fresh water green alga pithophora oedogonia (Mont.) Wittrock and evaluation of their antibacterial activity

Green synthesis of silver nanoparticles using nostoc linckia and its antimicrobial activity: a novel biological approach

Extracellular synthesis of silver nanoparticles by a marine alga, sargassum wightii grevilli and their antibacterial effects

Green synthesis, characterization of silver nanoparticles of a marine red alga spyridia fusiformis and their antibacterial activity

Green synthesis of silver nanoparticles using marine brown algae turbinaria conoides and its antibacterial activity

Ulvan as novel reducing and stabilizing agent from renewable algal biomass: application to green synthesis of silver nanoparticles

Straightforward green synthesis of "naked" aqueous silver nanoparticles

Silver nanoparticles for printable electronics and biological applications

One-step green synthesis of gold and silver nanoparticles with ascorbic acid and their versatile surface post-functionalization

Starch-directed green synthesis, characterization and morphology of silver nanoparticles

Laccase/TEMPO-mediated bacterial cellulose functionalization: production of paper-silver nanoparticles composite with antimicrobial activity

Novel precursors for green synthesis and application of silver nanoparticles in the realm of cotton finishing

Casein hydrolytic peptides mediated green synthesis of antibacterial silver nanoparticles

A novel green one-step synthesis of silver nanoparticles using chitosan: catalytic activity and antimicrobial studies

One-pot, large-scale green synthesis of silver nanoparticles-chitosan with enhanced antibacterial activity and low cytotoxicity

Green synthesis and characterization of silver/chitosan/polyethylene glycol nanocomposites without any reducing agent

Green synthesis of chondroitin sulfate-capped silver nanoparticles: characterization and surface modification

Low-cost and eco-friendly phytosynthesis of silver nanoparticles using cocos nucifera coir extract and its larvicidal activity

Synthesis, characterization and in vitro effects of 7 nm alloyed silver-gold nanoparticles

Completely green synthesis of dextrose reduced silver nanoparticles, its antimicrobial and sensing properties

Green synthesis of gallic acid-coated silver nanoparticles with high antimicrobial activity and low cytotoxicity to normal cells

Green synthesis and antimicrobial activity of silver nanoparticles using wild medicinal mushroom Ganoderma applanatum (Pers) Pat from Similipal Biosphere Reserve, Odisha India

Green synthesis and characterization of gelatin-based and sugarreduced silver nanoparticles

Novel silver nano-wedges for killing microorganisms

Green synthesis of small silver nanoparticles using geraniol and its cytotoxicity against fibrosarcomawehi 164

Green synthesis of silver nanoparticles-graphene oxide nanocomposite and its application in electrochemical sensing oftryptophan

Effect of accelerator in green synthesis of silver nanoparticles

Time-dependent effect in green synthesis of silver nanoparticles

Glutathione promoted expeditious green synthesis of silver nanoparticles in water using microwaves

Green synthesis of silver nanoparticles on nitrogen-doped graphene for hydrogen peroxide detection

Honey mediated green synthesis of silver nanoparticles

Green synthesis of silver nanoparticles by chemical reduction with hyaluronan

One-step green synthesis of antibacterial silver nanoparticles embedded in electrospun cyclodextrin nanofibers

Green synthesis and antibacterial activities of silver nanoparticles using extracellular laccase of lentinus edodes

Green synthesis of silver nanoparticles using local honey

Green synthesis of silver nanoparticles with sucrose and maltose: morphological and structural characterization

Malva parviflora extract assisted green synthesis of silver nanoparticles

Green synthesis of silver nanoparticles using glucan from mushroom and study of antibacterial activity

Green synthesis of silver nanoparticles using mushroom extract of pleurotus giganteus: characterization antimicrobial, and α-amylase inhibitory activity. Bionanoscience

Mussel-inspired green synthesis of silver nanoparticles on graphene oxide nanosheets for enhanced catalytic applications

Switchgrass (Panicum virgatum) extract mediated green synthesis of silver nanoparticles

Green synthesis of silver nanoparticles and study of their antimicrobial properties

Controlled silver nanoparticles synthesis in semi-hydrogel networks of poly (acrylamide) and carbohydrates: a rational methodology for antibacterial application

Onestep hydrothermal green synthesis of silver nanoparticle-carbon nanotube reduced-graphene oxide composite and its application as hydrogen peroxide sensor

Antifungal activity of silver nanoparticles obtained by green synthesis

Eco-friendly green synthesis of silver nanoparticles using Salmalia malabarica: synthesis, characterization, antimicrobial, and catalytic activity studies

Biosynthesis of silver nanoparticles and its antibacterial activity using seaweed Urospora sp

Stirring time effect of silver nanoparticles prepared in glutathione mediated by green method

Green synthesis of graphene/Ag nanocomposites

Antibacterial activity

Cobweb as novel biomaterial for the green and eco-friendly synthesis of silver nanoparticles

Green synthesis of colloid silver nanoparticles and resulting biodegradable starch/silver nanocomposites

Tannic acid-mediated green synthesis of antibacterial silver nanoparticles

A green protocol room temperature synthesis of silver nanoparticles in seconds

Green synthesis of silver nanoparticles using aqueous solution of Ficus benghalensis leaf extract and characterization of their antibacterial activity

Graphene oxide-silver nanocomposite as a highly effective antibacterial agent with species-specific mechanisms

Silver nanoparticles as potential antibacterial agents

Photothermal-assisted antibacterial application of graphene oxide-Ag nanocomposites against clinically isolated multi-drug resistant

Botryticidal activity of nanosized silver-chitosan composite and its application for the control of gray mold in strawberry

Antimicrobial properties of a novel silver-silica nanocomposite material

Synthesis, characterization and bactericidal activity of silica/silver core-shell nanoparticles

Anti-microbial efficiency of nano silver-silica modified geopolymer mortar for eco-friendly green construction technology

Immobilizing silver nanoparticles onto the surface of magnetic silica composite to prepare magnetic disinfectant with enhanced stability and antibacterial activity

Synergistic bactericidal activity of chlorhexidine-loaded, silver-decorated mesoporous silica

Antibiotic-loaded, silver core-embedded mesoporous silica nanovehicles as a synergistic antibacterial agent for the treatment of drug-resistant infections

Highly synergistic antimicrobial activity of spherical and flower-like hierarchical titanium dioxide/silver composites

Preparation, antibacterial, and antioxidant activities of silver/chitosan composites

Influence of polysaccharides molecular structure on the antibacterial activity and cytotoxicity of green synthesized composites based on silver nanoparticles and carboxymethyl-cellulose

Synthesis and antibacterial activity of (AgCl, Ag) NPs/diatomite hybrid composite

Fabrication of antibacterial monodispersed Ag-SiO2 core-shell nanoparticles with high concentration

Enhanced mechanical properties and bactericidal activity of polypropylene nanocomposite with dual-function silica-silver core-shell nanoparticles

Solid state photoreduction of silver on mesoporous silica to enhance antifungal activity

Antiviral therapies: advances and perspectives

Silver nanoparticle as antiviral agent and its uses

Plant-fungal interactions: what triggers the fungi to switch among lifestyles?

Mode of antiviral action of silver nanoparticles against HIV-1

Antiviral potential of nanoparticles-can nanoparticles fight against coronaviruses? Nanomaterials (2020

Efficiency of silver nanoparticle against virus coronaviruses

Silver nanoparticles inhibit hepatitis B virus replication

Silver nanoparticles inhibit hepatitis B virus replication

The silver lining: towards the responsible and limited usage of silver

Antimicrobial nanomaterials and coatings: current mechanisms and future perspectives to control the spread of viruses including SARS-CoV-2

Protective hybrid coating containing silver, copper and zinc cations effective against human immunodeficiency virus and other enveloped viruses

In vitro assessment of activity of graphene silver composite sheets against multidrug-resistant bacteria and tomato bushy stunt virus

Nanoparticles as potential antivirals in agriculture. Agriculture

Can nanotechnology help in the fight against COVID-19?

The potential of silver nanoparticles for antiviral and antibacterial applications: a mechanism of action

Nanotechnology-based antiviral therapeutics

Graphene oxide/silver nanoparticle ink formulations rapidly inhibit influenza A virus and OC43 coronavirus infection in vitro

Silver-based nanomaterials as therapeutic agents against coronaviruses: a review

Potent antiviral effect of silver nanoparticles on SARS-CoV-2

SARS-associated coronavirus replication in cell lines

Synthesis of silver nanoparticles, influence of capping agents, and dependence on size and shape: a review

Solid state synthesis of starch-capped silver nanoparticles

Nanoparticle capping agent dynamics and electron transfer: polymer-gated oxidation of silver nanoparticles

Effects of capping agents on the dispersion of silver nanoparticles

Inactivation of microbial infectiousness by silver nanoparticles-coated condom: a new approach to inhibit HIV-and HSV-transmitted infection

Antiviral activity of mycosynthesized silver nanoparticles against herpes simplex virus and human parainfluenza virus type 3

Antiviral activity of silver nanoparticle/chitosan composites against H1N1 influenza A virus

Inhibitory effect of silver nanomaterials on transmissible virusinduced host cell infections

Curcumin modified silver nanoparticles for highly efficient inhibition of respiratory syncytial virus infection

Antiviral activity of graphene-silver nanocomposites against non-enveloped and enveloped viruses

SiO2-Ag composite as a highly virucidal material: a roadmap that rapidly eliminates SARS-CoV-2. Nanomaterials

Development of novel antimicrobial and antiviral green synthesized silver nanocomposites for the visual detection of Fe 3+ ions

Genomic characterisation and epidemiology of 2019 novel coronavirus: implications for virus origins and receptor binding

Bat coronaviruses in China

A genomic perspective on the origin and emergence of SARS-CoV-2

Characterization of the receptor-binding domain (RBD) of 2019 novel coronavirus: implication for development of RBD protein as a viral attachment inhibitor and vaccine

Silver nanoparticles with bronchodilators through nebulisation to treat COVID 19 patients

Evaluation of silver nanoparticles for the prevention of SARS-CoV-2 infection in health workers: in vitro and in vivo

Nanoparticlebased strategies to combat COVID-19

Silver nanoparticles: synthesis, characterization, properties, applications, and therapeutic approaches

Antiviral activity of graphene oxide-silver nanocomposites by preventing viral entry and activation of the antiviral innate immune response

Recent advances in gold and silver nanoparticle based therapies for lung and breast cancers

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