Silver Nanoparticles as Potential Antiviral Agents

Development of a Silver-Doped High-Entropy Nitride Coating: Bactericidal and Antiviral Evaluation for Biomedical Applications

AISI 420 martensitic stainless steel is used for the manufacture of surgical and dental instruments, among others, whose surfaces can be colonized by bacteria and/or viruses that negatively affect the health of patients. The use of binary and ternary nitride coatings doped with different metallic nanoparticles has contributed to reducing the problems of infection with bacteria. However, there are few reports and studies on the biocidal and virucidal effect of high-entropy nitride coatings doped with silver nanoparticles, which could be an important alternative for antibacterial applications, also considering other advantages such as their excellent mechanical and tribological properties. In this work, a high-entropy nitride of (TiTaZrNbN)Agx doped with silver particles (Ag) was synthesized on AISI 420 stainless steel substrates via the magnetron sputtering technique. An attempt was made to elucidate the relationship between the microstructure and surface properties of the coatings with their potential activity against the selected bacteria and viruses. The Ag content in the coatings varied between 15.4 and 26.8 atom % by increasing the power supplied to the silver target between 50 and 110 W. The bactericidal effect of the synthesized nitride compound was studied via inhibition and adhesion tests against the bacteria Pseudomonas aeruginosa and Staphylococcus aureus. Moreover, the SARS-CoV-2 virus was selected to determine its virucidal effect. The deposited coatings exhibited columnar growth, and both the metal nitride matrix and the silver particles presented a NaCl-type cubic structure with preferential growth in the (111) and (200) planes. All of the coatings had a columnar structure whose width, surface roughness, and grain size increased with increasing silver content. Furthermore, the coatings present a hydrophobic behavior (increasing contact angle with increasing silver content) and decreasing surface energy. All of the coated steel samples strongly inhibited P. aeruginosa bacteria, and only sample RN-50W, with the lowest silver content, presented low adhesion of this bacteria. None of the coatings inhibited the S. aureus bacteria, and all of the coatings highly colonized the S. aureus bacteria in the adhesion test. The coatings deposited with powers of 50 and 90 W supplied to the silver target presented an average virucidal potential of 50% against the SARS-CoV-2 virus.

Nanomaterial-based approaches to neurotoxin neutralization in neurodegenerative diseases

Neurodegenerative diseases (NDs) are intricately linked to the accumulation of various neurotoxins, mainly including toxic proteins, inflammatory mediators, excess metal ions, and viral pathogens. Biological neutralization strategies that use agents to competitively bind harmful substances and thus inhibit their pathogenic activity hold promise for direct removal of neurotoxins but face many limitations and challenges in NDs. Nanomaterials provide a potential solution for neurotoxin neutralization in NDs due to their unique physicochemical and biological properties. This review summarizes recent advancements in nanomaterial-based approaches to neurotoxin neutralization in NDs, highlighting the diverse design principles and mechanisms of action. We also discuss the critical role of targeted delivery to optimize neutralization efficiency and the advantages of combining different neutralization mechanisms or introducing other therapeutic components to exert the synergistic effects. Furthermore, we reveal current limitations and future research directions aimed at paving the way for nanomedicine development based on neurotoxin neutralization for the treatment of NDs.

Antimicrobial, Quorum Sensing Inhibition, and Anti-Cancer Activities of Silver Nanoparticles Synthesized from Kenyan Bacterial Endophytes of Teclea nobilis

Untapped bioactive compounds from microbial endophytes offer a promising solution to counter antimicrobial and chemotherapeutic drug resistance when complexed as silver nanoparticles (AgNPs). AgNPs were biosynthesized using cell-free supernatants from endophytic Streptomyces sp. KE4D and Bacillus safensis KE4K isolated from the Kenyan medicinal plant Teclea nobilis, following fermentation in three different media. Bacterial extracts were analyzed using gas chromatography-mass spectrometry. AgNPs were characterized using Fourier-transform infrared spectroscopy and high-resolution transmission electron microscopy. Antimicrobial activity was assessed using agar well diffusion assays, and quorum sensing inhibition (QSI) was investigated using Chromobacterium violaceum. Anti-cancer potential was evaluated against breast (MCF-7) and prostate cancer (DU-145) cell lines using MTT assays. AgNPs were 5-55 nm in size, with KE4D AgNPs being spherical and KE4K AgNPs exhibiting various shapes. Cyclopropane acetic acids and fatty acids were identified as possible capping agents. Medium-dependent antimicrobial activity was observed, with medium Mannitol and medium 5294 AgNPs displaying stronger activity, particularly against Gram-negative indicators. KE4D medium 5294 AgNPs demonstrated 85.12% violacein inhibition at 140 µg/mL and better QSI activity, whilst KE4K AgNPs were better antimicrobials. The AgNPs IC50 values were <3.5 µg/mL for MCF-7 and <2.5 µg/mL for DU-145 cells. The bioactivity of biosynthesized AgNPs is influenced by the bacterial isolate and fermentation medium, suggesting that AgNP synthesis can be tailored for specific bioactivity.

Battling COVID-19 leveraging nanobiotechnology: Gold and silver nanoparticle-B-escin conjugates as SARS-CoV-2 inhibitors

The COVID-19 pandemic, an unprecedented global health crisis, has thrust humanity into a relentless battle with a variety of treatments and vaccines against the SARS-CoV-2 virus. Recent developments in nanotechnology have garnered significant interest in the application of metallic nanoparticles (NPs); specifically, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) have demonstrated antimicrobial and antiviral properties. This study investigates the molecular interactions between the receptor binding domains of five SARS-CoV-2 spike protein variants (Alpha, Beta, Delta, Omicron, and Gamma) and the angiotensin-converting enzyme 2 (ACE2) receptor, followed by the docking of AuNPs and AgNPs and the natural compound Beta-escin onto these complexes. As well as the inspection of both NPs against the virus main protease (Mpro) and RNA-dependent RNA polymerase (RdRp). Comprehensive computational simulations utilizing Autodock 4.2 and HDOCK server were employed to evaluate the binding affinities of these NPs toward key viral targets, SARS-CoV-2 Mpro, RdRp, and the spike glycoprotein. The results revealed that both AgNPs and AuNPs exhibited successful binding to the active pockets of SARS-CoV-2 Mpro, with slightly varying binding energies. In contrast, for RdRp, AgNPs demonstrated superior binding affinity compared to AuNPs, with differences in the residues involved in the binding pocket. AuNPs exhibited stronger binding affinities in the spike protein pocket. We also determined robust binding affinities between ACE2 and the spike variants, with the Omicron variant exhibiting the highest affinity. Subsequent docking of AuNPs and AgNPs revealed strong interactions with all ACE2-spike complexes, with AuNPs showing slightly higher affinities. The findings contribute to a deeper understanding of the interactions between NPs and viral proteins, shedding light on their mechanisms of action and their potential to offer innovative solutions for combating infectious diseases, particularly those caused by SARS-CoV-2.

Antiviral activity of silver nanoparticles against H1N1 influenza virus

BACKGROUND

Influenza virus is a significant cause of annual global respiratory disease and death. According to the limited availability of effective drugs and vaccines, innovative antivirals are currently being investigated as possible strategies to contain the spread of infectious agents. Among the various types of nanoparticles, silver nanoparticles (Ag-NPs) have attracted great interest due to their exceptional physicochemical properties. This study aims to investigate the antiviral activity of Ag-NPs against the influenza A virus (IAV)/H1N1.

METHODS

The MTT assay was used to determine the possible cytotoxicity of the Ag-NPs. Madin-Darby canine kidney (MDCK) cells were exposed to Ag-NPs extract in conjunction with 100 cell culture infectious dose 50% (CCID50) of virus administered at time intervals during the infection process. The antiviral activity of the extract was evaluated under pre-treatment, post-treatment, and simultaneous assay. Viral titer reduction was assayed using hemagglutination (HA) and CCID50 assays. Viral RNA relative quantification by real-time Polymerase Chain Reaction approach was performed in each experimental condition.

RESULTS

The study yielded significant findings regarding the inhibitory effects of Ag-NPs on the IAV/H1N1. Silver nanoparticles showed dose-dependent inhibition of the virus, with the strongest effect observed when administered simultaneously with the virus which the virus titer exhibited a substantial decrease from 5 Log10 in the control group to 1 Log10 in the initial samples, further reducing to 2 Log10 per milliliter at lower concentrations. Notably, Ag-NPs demonstrated a greater reduction in virus titer during the simultaneous stage, showing a statistically significant difference (P < 0.05) between the control and experimental groups). The reduction in viral titer was also evident in both pre- and post-inoculation stages, although the effects were different.

CONCLUSION

Silver nanoparticles possess inhibitory effects on the growth of the IAV/H1N1, with a significant reduction in virus titer. These findings suggest the potential of Ag-NPs as effective antiviral agents and highlight opportunities for further research and potential clinical applications in combating IAV (H1N1) infections.

Colloidal ZnAl-Layered Double Hydroxide Nanomaterials for Effective Prevention of SARS-CoV-2

SARS-CoV-2 is a threat to global public health, which requires the development of safe measures to reduce the spread of this coronavirus. Herein, in this study, we prepared and examined potential antiviral agents based on ZnAl-layered double hydroxide (ZnAl-LDH) materials. ZnAl-LDH-based samples were synthesized via a one-pot low-temperature coprecipitation method, which features an ultrathin structure. The incorporation of trace amounts of Ag induces the formation of ZnO particles on the ZnAl-LDH surface, where both ZnO and Ag enhance UV light absorption. Interestingly, ZnAl-LDH-Ag shows a significantly high anticoronavirus effect upon exposure to the daylight lamp of the operation console and ultraviolet light. Moreover, ZnAl-LDH and ZnAl-LDH-Ag potently blocked the entry of SARS-CoV-2 pseudoparticles to cells. The in vivo biocompatibility experiment has demonstrated that ZnAl-LDH-Ag is a potentially biocompatible and potent anti-SARS-CoV-2 agent for virus prevention. The synergistic interactions between these nanoparticles continuously generate reactive oxygen species (ROS), leading to effective and sustained viral inactivation. This light-sensitive ROS production introduces a photocatalytic inactivation mechanism in antiviral materials. Moreover, unlike conventional antiviral agents that rapidly deplete their active components, the layered structure of this composite enables the controlled long-term release of antiviral radicals, enhancing its durability. ZnAl-LDH-Ag has been expected to be a promising solution for long-lasting antiviral applications.

Pulmonary delivery of silver nanoparticles prevents influenza infection by recruiting and activating lymphoid cells

Silver nanoparticles (AgNPs) are a potential antiviral agent due to their ability to disrupt the viral particle or alter the virus metabolism inside the host cell. In vitro, AgNPs exhibit antiviral activity against the most common human respiratory viruses. However, their capacity to modulate immune responses during respiratory viral infections has yet to be explored. This study demonstrates that administering AgNPs directly into the lungs prior to infection can reduce viral loads and therefore virus-induced cytokines in mice infected with influenza virus or murine pneumonia virus. The prophylactic effect was diminished in mice with depleted lymphoid cells. We showed that AgNPs-treatment resulted in the recruitment and activation of lymphocytes in the lungs, particularly natural killer (NK) cells. Mechanistically, AgNPs enhanced the ability of alveolar macrophages to promote both NK cell migration and IFN-γ production. By contrast, following infection, in mice treated with AgNPs, NK cells exhibited decreased activation, indicating that these nanoparticles can regulate the potentially deleterious activation of these cells. Overall, the data suggest that AgNPs may possess prophylactic antiviral properties by recruiting and controlling the activation of lymphoid cells through interaction with alveolar macrophages.

β-CD@AgNPs with peroxisase-like activity for colorimetric determination of chiral tryptophan

Different enantiomer forms of amino acids play different roles in multifarious fields, and improper use will cause irreversible effects. Therefore, the identification of chiral amino acids is a vital issue in the field of pharmaceutical analysis. Herein, a chiral sensing system of β-cyclodextrin coated silver nanoparticle (β-CD@AgNPs) with peroxidase-like activity was designed for the fast and efficient colorimetric identification of tryptophan (Trp) enantiomers based on the difference in binding capacity between D/L-Trp and β-CD. The results showed the satisfactory linearity for detecting D/L-Trp over the concentration range from 0.2 to 4 mM with a LOD of 0.16 and 0.18 mM, respectively. Moreover, the absorbance increased linearly with the rise of D-Trp concentration percentage in the Trp enantiomer mixture. The proposed method avoided the use of natural enzymes and improved the stability due to the protective effect of cyclodextrin, which provided a new idea for selective colorimetric recognition and detection of D/L-Trp based on cyclodextrin.

Highly stable, antiviral, antibacterial cotton textiles via surface engineering

The unprecedented pandemic has highlighted the need for textiles that rapidly inactivate pathogens to protect public health. However, how to achieve rapid, effective and durable pathogen inactivation with the minimum antimicrobial dose loading has become a major challenge for cotton fabric modification. Here, a surface engineering cotton fabric (Co-CMC@Cu2+) was prepared by grafting carboxymethyl chitosan (CMC) onto cotton fabric and then loading with Cu2+ via coordination. The Co-CMC@Cu2+ with minimal copper ion dosage achieved rapid inactivation, excellent comfort, good biosafety, and durability. Specifically, Co-CMC modified with 12.5 mmol/L copper ion solutions achieved impressive bacterial reduction (BR) rates of 94.3 % and 89.3 % against E. coli and S. aureus, respectively, within 10 min of contact. Moreover, the bacteria were completely eradicated after 2 h of continuous contact. Additionally, Co-CMC@Cu2+ achieved excellent phage reduction (PR) rates of 98.9 % and 100 % against phi6 and phi-x174 bacteriophages, respectively, within 30 min of exposure, highlighting its potential for viral inactivation. Furthermore, Co-CMC@Cu2+ demonstrated exceptional durability for pathogen inactivation, with BR and PR values above 80 %, even after 150 washing cycles. This novel antimicrobial and antiviral cotton fabric will be a promising candidate textile to protect public health during a pandemic.

Eco-friendly synthesis of silver nanoparticles from peel and juice C. limon and their antiviral efficacy against HSV-1 and SARS-CoV-2

The growing threat of viral infections requires innovative therapeutic approaches to safeguard human health. Nanomaterials emerge as a promising solution to overcome the limitations associated with conventional therapies. The eco-friendly synthesis of silver nanoparticles (AgNPs) currently represents a method that guarantees antimicrobial efficacy, safety, and cost-effectiveness. This study explores the use of AgNPs derived from the peel (Lp-AgNPs) and juice (Lj-AgNPs) Citrus limon "Ovale di Sorrento", cultivars of the Campania region. The antiviral potential was tested against viruses belonging to the Coronaviridae and Herpesviridae. AgNPs were synthesized by reduction method using silver nitrate solution mixed with aqueous extract of C. limon peel and juice. The formation of Lp-AgNPs and Lj-AgNPs was assessed using a UV-Vis spectrophotometer. The size, ζ-potential, concentration, and morphology of AgNPs were evaluated by dynamic light scattering (DLS), nanoparticle tracking analysis (NTA), and field emission-scanning electron microscopy (FE-SEM). Cytotoxicity was evaluated in a concentration range between 500 and 7.8 µg/mL on VERO-76 and HaCaT cells, with the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium test bromide (MTT). Antiviral activity consisted of virus pre-treatment, co-treatment, cellular pre-treatment, and post-infection tests versus HSV-1 and SARS-CoV-2 at a multiplicity of infections (MOI) of 0.01. Plaque reduction assays and real-time PCR provided data on the antiviral potential of tested compounds. Lp-AgNPs and Lj-AgNPs exhibited spherical morphology with respective diameters of 60 and 92 nm with concentrations of 4.22 and 4.84 × 1010 particles/mL, respectively. The MTT data demonstrated minimal cytotoxicity, with 50 % cytotoxic concentrations (CC50) of Lp-AgNPs and Lj-AgNPs against VERO cells of 754.6 and 486.7 µg/mL. Similarly, CC50 values against HaCaT were 457.3 µg/mL for Lp-AgNPs and 339.6 µg/mL for Lj-AgNPs, respectively. In the virus pre-treatment assay, 90 % inhibitory concentrations of HSV-1 and SARS-CoV-2 were 8.54-135.04 µg/mL for Lp-AgNPs and 6.13-186.77 µg/mL for Lj-AgNPs, respectively. The molecular investigation confirmed the antiviral data, recording a reduction in the UL54 and UL27 genes for HSV-1 and in the Spike (S) gene for SARS-CoV-2, following AgNP exposure. The results of this study suggest that Lp-AgNPs and Lj-AgNPs derived from C. Limon could offer a valid ecological, natural, local and safe strategy against viral infections.

Silver Nanoparticles: A Comprehensive Review of Synthesis Methods and Chemical and Physical Properties

Recently, silver nanoparticles (NPs) have attracted significant attention for being highly desirable nanomaterials in scientific studies as a result of their extraordinary characteristics. They are widely known as effective antibacterial agents that are capable of targeting a wide range of pathogens. Their distinct optical characteristics, such as their localized surface plasmon resonance, enlarge their utilization, particularly in the fields of biosensing and imaging. Also, the capacity to control their surface charge and modify them using biocompatible substances offers improved durability and specific interactions with biological systems. Due to their exceptional stability and minimal chemical reactivity, silver NPs are highly suitable for a diverse array of biological applications. These NPs are produced through chemical, biological, and physical processes, each of which has distinct advantages and disadvantages. Chemical and physical techniques often encounter issues with complicated purification, reactive substances, and excessive energy usage. However, eco-friendly biological approaches exist, even though they require longer processing times. A key factor affecting the stability, size distribution, and purity of the NPs is the synthesis process selected. This review focuses on how essential it is to choose the appropriate synthesis method in order to optimize the characteristics and use of silver NPs.

Nanoparticle-Based Therapies for Neurotropic Viral Infections: Mechanisms, Challenges, and Future Prospects

Neurotropic viral infections pose a significant challenge due to their ability to target the central nervous system and cause severe neurological complications. Traditional antiviral therapies face limitations in effectively treating these infections, primarily due to the blood-brain barrier, which restricts the delivery of therapeutic agents to the central nervous system. Nanoparticle-based therapies have emerged as a promising approach to overcome these challenges. Nanoparticles offer unique properties that facilitate drug delivery across biological barriers, such as the blood-brain barrier, and can be engineered to possess antiviral activities.

Advancements in Green Nanoparticle Technology: Focusing on the Treatment of Clinical Phytopathogens

Opportunistic pathogenic microbial infections pose a significant danger to human health, which forces people to use riskier, more expensive, and less effective drugs compared to traditional treatments. These may be attributed to several factors, such as overusing antibiotics in medicine and lack of sanitization in hospital settings. In this context, researchers are looking for new options to combat this worrying condition and find a solution. Nanoparticles are currently being utilized in the pharmaceutical sector; however, there is a persistent worry regarding their potential danger to human health due to the usage of toxic chemicals, which makes the utilization of nanoparticles highly hazardous to eukaryotic cells. Multiple nanoparticle-based techniques are now being developed, offering essential understanding regarding the synthesis of components that play a crucial role in producing anti-microbial nanotherapeutic pharmaceuticals. In this regard, green nanoparticles are considered less hazardous than other forms, providing potential options for avoiding the extensive harm to the human microbiome that is prevalent with existing procedures. This review article aims to comprehensively assess the current state of knowledge on green nanoparticles related to antibiotic activity as well as their potential to assist antibiotics in treating opportunistic clinical phytopathogenic illnesses.

Nanoparticles-Delivered Circular RNA Strategy as a Novel Antitumor Approach

Anticancer therapy urgently needs the development of novel strategies. An innovative molecular target is represented by circular RNAs (circRNAs), single-strand RNA molecules with the 5' and 3' ends joined, characterized by a high stability. Although circRNA properties and biological functions have only been partially elucidated, their relationship and involvement in the onset and progression of cancer have emerged. Specific targeting of circRNAs may be obtained with antisense oligonucleotides and silencing RNAs. Nanotechnology is at the forefront of research for perfecting their delivery. Continuous efforts have been made to develop novel nanoparticles (NPs) and improve their performance, materials, and properties regarding biocompatibility and targeting capabilities. Applications in various fields, from imaging to gene therapy, have been explored. This review sums up the smart strategies developed to directly target circRNAs with the fruitful application of NPs in this context.

Albumin Nanoparticle-Based Drug Delivery Systems

Nanoparticle-based systems are extensively investigated for drug delivery. Among others, with superior biocompatibility and enhanced targeting capacity, albumin appears to be a promising carrier for drug delivery. Albumin nanoparticles are highly favored in many disease therapies, as they have the proper chemical groups for modification, cell-binding sites for cell adhesion, and affinity to protein drugs for nanocomplex generation. Herein, this review summarizes the recent fabrication techniques, modification strategies, and application of albumin nanoparticles. We first discuss various albumin nanoparticle fabrication methods, from both pros and cons. Then, we provide a comprehensive introduction to the modification section, including organic albumin nanoparticles, metal albumin nanoparticles, inorganic albumin nanoparticles, and albumin nanoparticle-based hybrids. We finally bring further perspectives on albumin nanoparticles used for various critical diseases.

Magnetic nanosystem a tool for targeted delivery and diagnostic application: Current challenges and recent advancement

Over the last two decades, researchers have paid more attention to magnetic nanosystems due to their wide application in diverse fields. The metal nanomaterials' antimicrobial and biocidal properties make them an essential nanosystem for biomedical applications. Moreover, the magnetic nanosystems could have also been used for diagnosis and treatment because of their magnetic, optical, and fluorescence properties. Superparamagnetic iron oxide nanoparticles (SPIONs) and quantum dots (QDs) are the most widely used magnetic nanosystems prepared by a simple process. By surface modification, researchers have recently been working on conjugating metals like silica, copper, and gold with magnetic nanosystems. This hybridization of the nanosystems modifies the structural characteristics of the nanomaterials and helps to improve their efficacy for targeted drug and gene delivery. The hybridization of metals with various nanomaterials like micelles, cubosomes, liposomes, and polymeric nanomaterials is gaining more interest due to their nanometer size range and nontoxic, biocompatible nature. Moreover, they have good injectability and higher targeting ability by accumulation at the target site by application of an external magnetic field. The present article discussed the magnetic nanosystem in more detail regarding their structure, properties, interaction with the biological system, and diagnostic applications.

Silversol® (a Colloidal Nanosilver Formulation) Inhibits Growth of Antibiotic-Resistant Staphylococcus aureus by Disrupting Its Physiology in Multiple Ways

Antibiotic-resistant strains of Staphylococcus aureus are being viewed as a serious threat by various public health agencies. Identifying novel targets in this important pathogen is crucial to the development of new effective antibacterial formulations. We investigated the antibacterial effect of a colloidal nanosilver formulation, Silversol®, against an antibiotic-resistant strain of S. aureus using appropriate in vitro assays. Moreover, we deciphered the molecular mechanisms underlying this formulation's anti-S. aureus activity using whole transcriptome analysis. Lower concentrations of the test formulation exerted a bacteriostatic effect against this pathogen, and higher concentrations exerted a bactericidal effect. Silversol® at sub-lethal concentration was found to disturb multiple physiological traits of S. aureus such as growth, antibiotic susceptibility, membrane permeability, efflux, protein synthesis and export, biofilm and exopolysaccharide production, etc. Transcriptome data revealed that the genes coding for transcriptional regulators, efflux machinery, transferases, β-lactam resistance, oxidoreductases, metal homeostasis, virulence factors, and arginine biosynthesis are expressed differently under the influence of the test formulation. Genes (argG and argH) involved in arginine biosynthesis emerged among the major targets of Silversol®'s antibacterial activity against S. aureus.

Breaking Barriers in Eco-Friendly Synthesis of Plant-Mediated Metal/Metal Oxide/Bimetallic Nanoparticles: Antibacterial, Anticancer, Mechanism Elucidation, and Versatile Utilizations

Nanotechnology has emerged as a promising field in pharmaceutical research, involving producing unique nanoscale materials with sizes up to 100 nm via physiochemical and biological approaches. Nowadays more emphasis has been given to eco-friendly techniques for developing nanomaterials to enhance their biological applications and minimize health and environmental risks. With the help of green nanotechnology, a wide range of green metal, metal oxide, and bimetallic nanoparticles with distinct chemical compositions, sizes, and morphologies have been manufactured which are safe, economical, and environment friendly. Due to their biocompatibility and vast potential in biomedical (antibacterial, anticancer, antiviral, analgesic, anticoagulant, biofilm inhibitory activity) and in other fields such as (nanofertilizers, fermentative, food, and bioethanol production, construction field), green metal nanoparticles have garnered significant interest worldwide. The metal precursors combined with natural extracts such as plants, algae, fungi, and bacteria to get potent novel metal, metal oxide, and bimetallic nanoparticles such as Ag, Au, Co, Cu, Fe, Zr, Zn, Ni, Pt, Mg, Ti, Pd, Cd, Bi2O3, CeO2, Co3O4, CoFe2O4, CuO, Fe2O3, MgO, NiO, TiO2, ZnO, ZrO2, Ag-Au, Ag-Cr, Ag-Cu, Ag-Zn, Ag-CeO2, Ag-CuO, Ag-SeO2, Ag-TiO2, Ag-ZnO, Cu-Ag, Cu-Mg, Cu-Ni, Pd-Pt, Pt-Ag, ZnO-CuO, ZnO-SeO, ZnO-Se, Se-Zr, and Co-Bi2O3. These plant-mediated green nanoparticles possess excellent antibacterial and anticancer activity when tested against several microorganisms and cancer cell lines. Plants contain essential phytoconstituents (polyphenols, flavonoids, terpenoids, glycosides, alkaloids, etc.) compared to other natural sources (bacteria, fungi, and algae) in higher concentration that play a vital role in the development of green metal, metal oxide, and bimetallic nanoparticles because these plant-phytoconstituents act as a reducing, stabilizing, and capping agent and helps in the development of green nanoparticles. After concluding all these findings, this review has been designed for the first time in such a way that it imparts satisfactory knowledge about the antibacterial and anticancer activity of plant-mediated green metal, metal oxide, and bimetallic nanoparticles together, along with antibacterial and anticancer mechanisms. Additionally, it provides information about characterization techniques (UV–vis, FT-IR, DLS, XRD, SEM, TEM, BET, AFM) employed for plant-mediated nanoparticles, biomedical applications, and their role in other industries. Hence, this review provides information about the antibacterial and anticancer activity of various types of plant-mediated green metal, metal oxide, and bimetallic nanoparticles and their versatile application in diverse fields which is not covered in other pieces of literature.

Silver and gold nanoparticles: Eco-friendly synthesis, antibiofilm, antiviral, and anticancer bioactivities

For the first time in this study, silver nanoparticles (AgNPs) and gold nanoparticles (AuNPs) were green synthesized by the cost-effective and eco-friendly procedure using Cotton seed meal and Fodder yeast extracts. The biosynthesized NPs were characterized by UV-Vis spectroscopy, dynamic light scattering analysis (DLS), transmission electron microscopy (TEM), selected area electron diffraction (SAED), and fourier-transform infrared (FTIR) spectroscopy. Furthermore, the biosynthesized NPs were tested in vitro against biofilm formation by some pathogenic negative bacteria (Escherichia coli, Proteus mirabilis, Klebsiella sp., Salmonella sp., and Pseudomonas aeruginosa) and negative bacteria (staphylococcus aureus) as well as against human denovirus serotype 5 (HAdV-5) and anticancer activity using HepG2 hepatocarcinoma cells. UV-Vis absorption spectra of reaction mixture of AgNPs and AuNPs exhibited maximum absorbance at 440 nm and 540 nm, respectively. This finding was confirmed by DLS measurements that the highest intensity of the AgNPs and AuNPs were 84 nm and 73.9 nm, respectively. FTIR measurements identified some functional groups detected in Cotton seed meal and Fodder yeast extracts that could be responsible for reduction of silver and gold ions to metallic silver and gold. The morphologies and particle size of AgNPs and AuNPs were confirmed by the TEM and SAED pattern analysis. Biosynthesized AgNPs and AuNPs showed good inhibitory effects against biofilms produced by Escherichia coli, Proteus mirabilis, Klebsiella sp., Salmonella sp., Pseudomonas aeruginosa, and Staphylococcus aureus. In addition, they showed anticancer activities against hepatocellular carcinoma (HepG-2) and antiviral activity against human adenovirus serotype 5 infection in vitro. Finally, the results of this study is expected to be extremely helpful to nano-biotechnology, pharmaceutical, and food packing applications through developing antimicrobial and/or an anticancer drugs from ecofriendly and inexpensive nanoparticles with multi-potentiality.

Nanoparticle‑based antiviral strategies to combat the influenza virus (Review)

The rapid availability of effective antiviral treatments would be beneficial during the early phases of a pandemic, as they could reduce viral loads and control serious infections until antigenic vaccines become widely available. One promising alternative therapy to combat pandemics is nanotechnology, which has the potential to inhibit a wide variety of viruses, including the influenza virus. This review summarizes the recent progress using gold, copper, silver, silicone, zinc and selenium nanoparticles, since these materials have shown remarkable antiviral capacity against influenza A virus.

Bioinspired silver nanoparticle-based nanocomposites for effective control of plant pathogens: A review

Plant pathogens, including bacteria, fungi, and viruses, pose significant challenges to the farming community due to their extensive diversity, the rapidly evolving phenomenon of multi-drug resistance (MDR), and the limited availability of effective control measures. Amid mounting global pressure, particularly from the World Health Organization, to limit the use of antibiotics in agriculture and livestock management, there is increasing consideration of engineered nanomaterials (ENMs) as promising alternatives for antimicrobial applications. Studies focusing on the application of ENMs in the fight against MDR pathogens are receiving increasing attention, driven by significant losses in agriculture and critical knowledge gaps in this crucial field. In this review, we explore the potential contributions of silver nanoparticles (AgNPs) and their nanocomposites in combating plant diseases, within the emerging interdisciplinary arena of nano-phytopathology. AgNPs and their nanocomposites are increasingly acknowledged as promising countermeasures against plant pathogens, owing to their unique physicochemical characteristics and inherent antimicrobial properties. This review explores recent advancements in engineered nanocomposites, highlights their diverse mechanisms for pathogen control, and draws attention to their potential in antibacterial, antifungal, and antiviral applications. In the discussion, we briefly address three crucial dimensions of combating plant pathogens: green synthesis approaches, toxicity-environmental concerns, and factors influencing antimicrobial efficacy. Finally, we outline recent advancements, existing challenges, and prospects in scholarly research to facilitate the integration of nanotechnology across interdisciplinary fields for more effective treatment and prevention of plant diseases.

Valorizing pomegranate wastes by producing functional silver nanoparticles with antioxidant, anticancer, antiviral, and antimicrobial activities and its potential in food preservation

The food sector generates massive amounts of waste, which are rich in active compounds, especially polyphenols; therefore, valorizing these wastes is a global trend. In this study, we produce silver nanoparticles from pomegranate wastes, characterized by enhanced antioxidant, anticancer, antiviral, and antimicrobial properties and investigated their potential to maintain the fruit quality for sixty days in market. The pomegranate waste-mediated silver nanoparticles (PPAgNPs) were spherical shape (measured by TEM), 20 nm (Zeta sizer), negatively charged -25.98 mV (Zeta potential), and surrounded by active groups (FTIR). The PPAgNPs scavenged 94 % of DPPH radicals and inhibited the growth of pathogens, i.e., Staphylococcus aureus, Listeria monocytogenes, Campylobacter jejuni, Salmonella typhi and Candida with inhibition zones diameters (16-45 mm). They impeded the development of breast and colon cancer cell lines by 80 and 78 %, increased the activity of apoptosis marker caspase 3, and inhibited 82 % of COVID-19. The PPAgNPs were added to the rat diet at 80, 160, and 320 µg/kg levels. PPAgNPs administered at a concentration of 160 µg/kg in the rat diet resulted in the best growth performance, normal liver and kidney parameters (p = 0.029-0.038), lowered lipid profile, malondialdhyde (MDA), and raised glutathion reduced (GSH), total protein (TP). Also, the reduced gene expression of Interleukin 6 (IL-6) and Tumor necrosis factor alpha (TNF-α) in albino rats' serum indicates the anti-inflammatory effect of PPAgNPs. PPAgNPs developed a functional coating to preserve mandarin fruit for 60 days by dipping technique. The active coat containing PPAgNPs can effectively preserve the fruit for 60 days.

Biological mechanism of ZnO nanomaterials

Modern nanotechnology has made zinc oxide nanomaterials (ZnO NMts) multifunctional, stable, and low cost, enabling them to be widely used in commercial and biomedical fields. With its wide application, the risk of human direct contact and their release into the environment also increases. This review aims to summarize the toxicity studies of ZnO NMts in vivo, including neurotoxicity, inhalation toxicity, and reproductive toxicity. The antibacterial and antiviral mechanisms of ZnO NMts in vitro and the toxicity to eukaryotic cells were summarized. The summary found that it was mainly related to reactive oxygen species (ROS) produced by oxidative stress. It also discusses the potential harm to body and the favorable prospects of the widespread use of antibacterial and antiviral in the future medical field. The review also emphasizes that the dosage and use method of ZnO NMts will be the focus of future biomedical research.

Enhanced in vivo antiviral activity against pseudorabies virus through transforming gallic acid into graphene quantum dots with stimulation of interferon-related immune responses

With the urgent need for antiviral agents, antiviral materials with high biocompatibility and antiviral effects have attracted a lot of attention. In this study, gallic acid, a natural polyphenolic compound, was transformed into biocompatible graphene quantum dots (GAGQDs) which exhibit enhanced antiviral activity against pseudorabies virus (PRV). The as-prepared GAGQDs inhibit PRV proliferation with a 104-fold reduction in viral titers. Investigation of the antiviral mechanism revealed that GAGQDs inhibit the adsorption, invasion and replication of PRV infection. Treatment with GAGQDs regulates the expression levels of interferon-related antiviral proteins, including mitochondrial antiviral-signaling protein (MAVS), signal transducer and activator of transcription 1 (STAT1) and 2',5'-oligoadenylate synthetase 1 (OAS1), suggesting that GAGQDs can stimulate innate antiviral immune responses, resulting in enhanced antiviral effects. More importantly, GAGQD treatments alleviate clinical symptoms and reduce mortality in PRV-infected mice. Our results reveal the enhanced therapeutic effects of GAGQDs against PRV infection in vitro and in vivo, suggesting the potential of GAGQDs as a promising novel antiviral agent.

Current Overview of Metal Nanoparticles' Synthesis, Characterization, and Biomedical Applications, with a Focus on Silver and Gold Nanoparticles

Metal nanoparticles (NPs) have garnered considerable attention, due to their unique physicochemical properties, that render them promising candidates for various applications in medicine and industry. This article offers a comprehensive overview of the most recent advancements in the manufacturing, characterization, and biomedical utilization of metal NPs, with a primary focus on silver and gold NPs. Their potential as effective anticancer, anti-inflammatory, and antimicrobial agents, drug delivery systems, and imaging agents in the diagnosis and treatment of a variety of disorders is reviewed. Moreover, their translation to therapeutic settings, and the issue of their inclusion in clinical trials, are assessed in light of over 30 clinical investigations that concentrate on administering either silver or gold NPs in conditions ranging from nosocomial infections to different types of cancers. This paper aims not only to examine the biocompatibility of nanomaterials but also to emphasize potential challenges that may limit their safe integration into healthcare practices. More than 100 nanomedicines are currently on the market, which justifies ongoing study into the use of nanomaterials in medicine. Overall, the present review aims to highlight the potential of silver and gold NPs as innovative and effective therapeutics in the field of biomedicine, citing some of their most relevant current applications.

Metabolomics-directed nanotechnology in viral diseases management: COVID-19 a case study

The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently regarded as the twenty-first century's plague accounting for coronavirus disease 2019 (COVID-19). Besides its reported symptoms affecting the respiratory tract, it was found to alter several metabolic pathways inside the body. Nanoparticles proved to combat viral infections including COVID-19 to demonstrate great success in developing vaccines based on mRNA technology. However, various types of nanoparticles can affect the host metabolome. Considering the increasing proportion of nano-based vaccines, this review compiles and analyses how COVID-19 and nanoparticles affect lipids, amino acids, and carbohydrates metabolism. A search was conducted on PubMed, ScienceDirect, Web of Science for available information on the interrelationship between metabolomics and immunity in the context of SARS-CoV-2 infection and the effect of nanoparticles on metabolite levels. It was clear that SARS-CoV-2 disrupted several pathways to ensure a sufficient supply of its building blocks to facilitate its replication. Such information can help in developing treatment strategies against viral infections and COVID-19 based on interventions that overcome these metabolic changes. Furthermore, it showed that even drug-free nanoparticles can exert an influence on biological systems as evidenced by metabolomics.

Polycladia myrica-based delivery of selenium nanoparticles in combination with radiotherapy induces potent in vitro antiviral and in vivo anticancer activities against Ehrlich ascites tumor

Background: Over the last few decades, nanotechnology has entered daily life through various applications, therefore, there has been a trend toward developing new approaches to green-mediated nanotechnology that encourage nanomaterial formation through biological methods such as plants or microorganisms. Algae have gained increasing attention from nanotechnology scientists and have paved the way for the emergence of "algae nanotechnology" as a promising field. Methods: Via using the aqueous extract of the brown alga Polycladia myrica, selenium nanoparticles were synthesized and characterized by using seven instruments: SEM, TEM, UV spectra, Zeta potential, EDX, X-ray diffraction, and FTIR. P. myrica selenium nanoparticles (PoSeNPs) were then examined for their antiviral activity against HSV-1 (Herpes simplex I) and anticancer against human colon cancer cell line (HCT-116) in vitro and in vivo alone and in combination with laser therapy of power 2 mW against Ehrlich carcinoma (EAC). Results: PoSeNPs ranging between 17.48 nm and 23.01 nm in size, and EDX revealed the selenium mass and its atoms as 0.46% ± 0.07% and 0.08% ± 0.01% respectively. Their anticancer potentiality in vitro was with maximum inhibitions of 80.57% and 73% and IC50 = 14.86 μg/mL and 50 mg/mL against HCT-116 and EAC cell lines respectively, while their in vivo alone and in combination with laser therapy of power 2 mW showed a potent therapy effect against Ehrlich ascites carcinoma (EAC). Conclusion: This study concluded that PoSeNPs do not have a toxic effect; they exhibit high effectiveness as a photothermal agent for cancer therapy, with promising applications in future biomedical fields. The combined therapy showed a significant decrease in tumor volume, massive tumor cell necrosis, shrinking, and disappearance. It also showed improvement in liver TEM, histology, kidney function: urea and creatinine, and liver enzymes: ALT, and AST.

A Comparative Study of Cancer Cells Susceptibility to Silver Nanoparticles Produced by Electron Beam

Introduction: Silver nanoparticles (AgNPs) have a wide range of bioactivity, which is highly dependent on particle size, shape, stabilizer, and production method. Here, we present the results of studies of AgNPs cytotoxic properties obtained by irradiation treatment of silver nitrate solution and various stabilizers by accelerating electron beam in a liquid medium. Methods: The results of studies of morphological characteristics of silver nanoparticles were obtained by transmission electron microscopy, UV-vis spectroscopy, and dynamic light scattering measurements. MTT test, alamar blue test, flow cytometry, and fluorescence microscopy were used to study the anti-cancer properties. As biological objects for standard tests, adhesive and suspension cell cultures of normal and tumor origin, including prostate cancer, ovarian cancer, breast cancer, colon cancer, neuroblastoma, and leukemia, were studied. Results: The results showed that the silver nanoparticles obtained by irradiation with polyvinylpyrrolidone and collagen hydrolysate are stable in solutions. Samples with different stabilizers were characterized by a wide average size distribution from 2 to 50 nm and low zeta potential from −7.3 to +12.4 mV. All AgNPs formulations showed a dose-dependent cytotoxic effect on tumor cells. It has been established that the particles obtained with the combination of polyvinylpyrrolidone/collagen hydrolysate have a relatively more pronounced cytotoxic effect in comparison to samples stabilized with only collagen or only polyvinylpyrrolidone. The minimum inhibitory concentrations for nanoparticles were less than 1 μg/mL for various types of tumor cells. It was found that neuroblastoma (SH-SY5Y) is the most susceptible, and ovarian cancer (SKOV-3) is the most resistant to the action of silver nanoparticles. The activity of the AgNPs formulation prepared with a mixture of PVP and PH studied in this work was higher that activity of other AgNPs formulations reported in the literature by about 50 times. Conclusions: The results indicate that the AgNPs formulations synthesized with an electron beam and stabilized with polyvinylpyrrolidone and protein hydrolysate deserve deep study for their further use in selective cancer treatment without harming healthy cells in the patient organism.

Glycyrrhizic Acid-Based Carbonized Dots Boost Antiviral Activity against Influenza A Virus via Multisite Inhibition Mechanisms

Influenza A virus (IVA) has been continuously causing pandemics in several animal hosts and has become a worldwide public health threat. Currently, antiviral drugs have become associated with a lot of side effects and limited activity against emerging drug-resistant influenza viruses. Therefore, the development of novel antiviral drugs is of great importance. In this study, we synthesized a kind of carbon dots (CDs) with high dispersibility from glycyrrhizic acid (GA) using a simple dry heating method. Compared with glycyrrhizic acid alone, GA-CDs exhibit superior solubility and significantly improve the antiviral property against IVA. Investigation of the mechanism revealed that GA-CDs act against IVA mainly by inhibiting viral internalization, replication of the viral genome, neuraminidase activity, and host inflammatory responses. More importantly, in a mouse model, GA-CDs can significantly alleviate the clinical symptoms and decrease mortality and lung viral titers. In vitro and in vivo experiments demonstrate that GA-CDs possess extraordinary therapeutic effects; therefore, we propose that GA-CDs may be a promising alternative therapy for IVA infection.

Reduction in the COVID-19 pneumonia case fatality rate by silver nanoparticles: A randomized case study

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2), which causes coronavirus disease 2019 (COVID-19), has devastated mankind. To date, no approved treatment is available to completely combat this disease. Although many studies reported the potential of silver nanoparticles' (AgNPs) action mechanism and effect against SARS-CoV-2, this is the first clinical trial that aimed to prove this effect. This open-label, randomized, parallel-group, investigator-initiated study (IIS) was conducted in India from 2021 to 2022 and included 40 patients diagnosed with moderately-severe to severe COVID-19 pneumonia. This study proved a significantly higher survival rates (p < 0.05) and significantly lower number of days until supplemental oxygenation was required (p < 0.0001) for patients receiving intravenous AgNPs in form of AgSept® in addition to the standard COVID-19 treatment. This study highlights the importance of intravenous AgNPs administration in the treatment of virus-induced pneumonia.

Identifying the Anti-MERS-CoV and Anti-HcoV-229E Potential Drugs from the Ginkgo biloba Leaves Extract and Its Eco-Friendly Synthesis of Silver Nanoparticles

The present study aimed to estimate the antiviral activities of Ginkgo biloba (GB) leaves extract and eco-friendly free silver nanoparticles (Ag NPs) against the MERS-CoV (Middle East respiratory syndrome-coronavirus) and HCoV-229E (human coronavirus 229E), as well as isolation and identification of phytochemicals from GB. Different solvents and high-performance liquid chromatography (HPLC) were used to extract and identify flavonoids and phenolic compounds from GB leaves. The green, silver nanoparticle synthesis was synthesized from GB leaves aqueous extract and investigated for their possible effects as anti-coronaviruses MERS-CoV and HCoV-229E using MTT assay protocol. To verify the synthesis of Ag NPs, several techniques were employed, including X-ray diffraction (XRD), scan, transmission electron microscopy, FT-IR, and UV-visible spectroscopy. The highest contents of flavonoids and phenolic compounds were recorded for acetone, methanol, and ethanol as mixtures with water, in addition to pure water. HPLC flavonoids were detected as apegenin, luteolin, myricetin, and catechin, while HPLC phenolic compounds were pyrogallol, caffeic acid, gallic acid, and ellagic acid. In addition, our results revealed that Ag NPs were produced through the shift from yellow to dark brown. TEM examination of Ag NPs revealed spherical nanoparticles with mean sizes ranging from 5.46 to 19.40 nm and an average particle diameter of 11.81 nm. A UV-visible spectrophotometric investigation revealed an absorption peak at λ max of 441.56 nm. MTT protocol signified the use of GB leaves extract as an anti-coronavirus to be best from Ag NPs because GB extract had moderate anti-MERS-CoV with SI = 8.94, while had promising anti-HCov-229E, with an SI of 21.71. On the other hand, Ag NPs had a mild anti-MERS-CoV with SI = 4.23, and a moderate anti-HCoV-229E, with an SI of 7.51.

Silver nanoparticles inhibit goatpox virus replication

No effective drugs against goatpox virus (GTPV) exist despite the high morbidity and mortality (up to 100%) caused by this virus. In this study, the antiviral activity of silver nanoparticles (AgNPs) against GTPV, a member of the genus Capripoxvirus, was evaluated. Piper betle leaf extract was used as a reducing agent during the biological synthesis of AgNPs from silver nitrate. The AgNPs were characterized using ultraviolet/visible (UV/vis) absorption spectroscopy, X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and transmission electron microscopy (TEM). AgNPs were tested at different concentrations as antiviral agents against GTPV, and the reduction in the median tissue culture infectious dose (TCID₅₀/mL) was used to quantitate antiviral activity. AgNPs caused significant inhibition of GTPV replication by preventing virus entry into the host cell. Pre-treatment of cells with AgNPs caused a slight reduction in infectivity, but this did not significantly correlate with the effect on virus attachment. AgNPs also appeared to significantly reduce the viral genome copy number. This study demonstrates that the AgNPs are capable of inhibiting GTPV replication in vitro.

Nanodelivery of antiretroviral drugs to nervous tissues

Despite the development of effective combined antiretroviral therapy (cART), the neurocognitive impairments associated with human immunodeficiency virus (HIV) remain challenging. The presence of the blood-brain barrier (BBB) and blood-cerebrospinal fluid barrier (BCFB) impedes the adequate penetration of certain antiretroviral drugs into the brain. In addition, reports have shown that some antiretroviral drugs cause neurotoxicity resulting from their interaction with nervous tissues due to long-term systemic exposure. Therefore, the research into the effective therapeutic modality that would cater for the HIV-associated neurocognitive disorders (HAND) and ART toxicity is now receiving broad research attention. Thus, this review explores the latest information in managing HAND using a nanoparticle drug delivery system (NDDS). We discussed the neurotoxicity profile of various approved ART. Also, we explained the applications of silver nanoparticles (AgNPs) in medicine, their different synthesis methods and their interaction with nervous tissues. Lastly, while proposing AgNPs as useful nanoparticles in properly delivering ART to enhance effectiveness and minimize neurocognitive disorders, we hypothesize that the perceived toxicity of AgNPs could be minimized by taking appropriate precautions. One such precaution is using appropriate reducing and stabilizing agents such as trisodium citrate to reduce silver ion Ag + to ground state Ag0 during the synthesis. Also, the usage of medium-sized, spherical-shaped AgNPs is encouraged in AgNPs-based drug delivery to the brain due to their ability to deliver therapeutic agents across BBB. In addition, characterization and functionalization of the synthesized AgNPs are required during the drug delivery approach. Putting all these factors in place would minimize toxicity and enhance the usage of AgNPs in delivering therapeutic agents across the BBB to the targeted brain tissue and could cater for the HIV-associated neurocognitive disorders and neurotoxic effects of antiretroviral drugs (ARDs).

Nanoscale Technologies in the Fight against COVID-19: From Innovative Nanomaterials to Computer-Aided Discovery of Potential Antiviral Plant-Derived Drugs

The last few years have increasingly emphasized the need to develop new active antiviral products obtained from artificial synthesis processes using nanomaterials, but also derived from natural matrices. At the same time, advanced computational approaches have found themselves fundamental in the repurposing of active therapeutics or for reducing the very long developing phases of new drugs discovery, which represents a real limitation, especially in the case of pandemics. The first part of the review is focused on the most innovative nanomaterials promising both in the field of therapeutic agents, as well as measures to control virus spread (i.e., innovative antiviral textiles). The second part of the review aims to show how computer-aided technologies can allow us to identify, in a rapid and therefore constantly updated way, plant-derived molecules (i.e., those included in terpenoids) potentially able to efficiently interact with SARS-CoV-2 cell penetration pathways.

Nanoparticles of Bioactive Metals/Metal Oxides and Their Nanocomposites with Antibacterial Drugs for Biomedical Applications

The increasing appearance of new strains of microorganisms resistant to the action of existing antibiotics is a modern problem that requires urgent decision. A promising potential solution is the use of nanoparticles of bioactive metals and their oxides as new antibacterial agents, since they are capable of affecting pathogenic microorganisms by mechanisms different from the mechanisms of action of antibiotics. Inorganic nanoparticles possess a wide spectrum of antibacterial activity. These particles can be easily conjugated with drug molecules and become carriers in targeted drug-delivery systems. This paper discusses the benefits and prospects of the application of nanoparticles from metals and metal oxides and their nanocomposites with antibacterial drugs.

Recent advances on therapeutic potentials of gold and silver nanobiomaterials for human viral diseases

Viral diseases are prominent among the widely spread infections threatening human well-being. Real-life clinical successes of the few available therapeutics are challenged by pathogenic resistance and suboptimal delivery to target sites. Nanotechnology has aided the design of functionalised and non-functionalised Au and Ag nanobiomaterials through physical, chemical and biological (green synthesis) methods with improved antiviral efficacy and delivery. In this review, innovative designs as well as interesting antiviral activities of the nanotechnology-inclined biomaterials of Au and Ag, reported in the last 5 years were critically overviewed against several viral diseases affecting man. These include influenza, respiratory syncytial, adenovirus, severe acute respiratory syndromes (SARS), rotavirus, norovirus, measles, chikungunya, HIV, herpes simplex virus, dengue, polio, enterovirus and rift valley fever virus. Notably identified among the nanotechnologically designed promising antiviral agents include AuNP-M2e peptide vaccine, AgNP of cinnamon bark extract and AgNP of oseltamivir for influenza, PVP coated AgNP for RSV, PVP-AgNPs for SARS-CoV-2, AuNRs of a peptide pregnancy-induce d hypertension and AuNP nanocarriers of antigen for MERS-CoV and SARS-CoV respectively. Others are AgNPs of collagen and Bacillus subtilis for rotavirus, AgNPs labelled Ag30-SiO 2 for murine norovirus in water, AuNPs of Allium sativum and AgNPs of ribavirin for measles, AgNPs of Citrus limetta and Andrographis Paniculata for Chikungunya, AuNPs of efavirenz and stavudine, and AgNPs-curcumin for HIV, NPAuG3-S8 for HSV, AgNPs of Moringa oleifera and Bruguiera cylindrica for dengue while AgNPs of polyethyleneimine and siRNA analogues displayed potency against enterovirus. The highlighted candidates are recommended for further translational studies towards antiviral therapeutic designs.