Surfactant-modified nanoclay exhibits an antiviral activity with high potency and broad spectrum

Silicon-containing nanomedicine and biomaterials: materials chemistry, multi-dimensional design, and biomedical application

The invention of silica-based bioactive glass in the late 1960s has sparked significant interest in exploring a wide range of silicon-containing biomaterials from the macroscale to the nanoscale. Over the past few decades, these biomaterials have been extensively explored for their potential in diverse biomedical applications, considering their remarkable bioactivity, excellent biocompatibility, facile surface functionalization, controllable synthesis, etc. However, to expedite the clinical translation and the unexpected utilization of silicon-composed nanomedicine and biomaterials, it is highly desirable to achieve a thorough comprehension of their characteristics and biological effects from an overall perspective. In this review, we provide a comprehensive discussion on the state-of-the-art progress of silicon-composed biomaterials, including their classification, characteristics, fabrication methods, and versatile biomedical applications. Additionally, we highlight the multi-dimensional design of both pure and hybrid silicon-composed nanomedicine and biomaterials and their intrinsic biological effects and interactions with biological systems. Their extensive biomedical applications span from drug delivery and bioimaging to therapeutic interventions and regenerative medicine, showcasing the significance of their rational design and fabrication to meet specific requirements and optimize their theranostic performance. Additionally, we offer insights into the future prospects and potential challenges regarding silicon-composed nanomedicine and biomaterials. By shedding light on these exciting research advances, we aspire to foster further progress in the biomedical field and drive the development of innovative silicon-composed nanomedicine and biomaterials with transformative applications in biomedicine.

Recent Advances in Antivirals for Japanese Encephalitis Virus

Culex mosquitoes are the primary vectors of the Japanese encephalitis virus (JEV). Since its discovery in 1935, Japanese encephalitis (JE), caused by JEV, has posed a significant threat to human health. Despite the widespread implementation of several JEV vaccines, the transmission chain of JEV in the natural ecosystem has not changed, and the vector of transmission cannot be eradicated. Therefore, JEV is still the focus of attention for flaviviruses. At present, there is no clinically specific drug for JE treatment. JEV infection is a complex interaction between the virus and the host cell, which is the focus of drug design and development. An overview of antivirals that target JEV elements and host factors is presented in this review. In addition, drugs that balance antiviral effects and host protection by regulating innate immunity, inflammation, apoptosis, or necrosis are reviewed to treat JE effectively.

Synergistic Effects of Silicate-Platelet Supporting Ag and ZnO, Offering High Antibacterial Activity and Low Cytotoxicity

Silver nanoparticles (AgNPs) are remarkably able to eliminate microorganisms, but induce cytotoxicity in mammalian cells, and zinc oxide nanoparticles (ZnONPs) are considered to have a wide bactericidal effect with weak cytotoxicity. In this study, both zinc oxide nanoparticles and silver nanoparticles were co-synthesized on a nano-silicate platelet (NSP) to prepare a hybrid of AgNP/ZnONP/NSP. Ultraviolet-visible spectroscopy (UV-Vis), X-ray diffraction (XRD), and transmission electron microscopy (TEM) were used to characterize the formation of nanoparticles on the NSP. Synthesized ZnONP/NSP (ZnONP on NSP) was confirmed by the absorption peaks on UV-Vis and XRD. AgNP synthesized on ZnONP/NSP was also characterized by UV-Vis, and ZnONP/NSP showed no interference with synthesis. The images of TEM demonstrated that NSP provides physical support for the growth of nanoparticles and could prevent the inherent aggregation of ZnONP. In antibacterial tests, AgNP/ZnONP/NSP exhibited more efficacy against Staphylococcus aureus (S. aureus) than ZnONP/NSP (ZnONP was synthesized on NSP) and AgNP/NSP (AgNP was synthesized on NSP). In cell culture tests, 1/10/99 (weight ratio) of AgNP/ZnONP/NSP exhibited low cytotoxicity for mammalian cells (>100 ppm). Therefore, AgNP/ZnONP/NSP, containing both AgNP and ZnONP, with both strong antibacterial qualities and low cytotoxicity, showed potentially advantageous medical utilizations due to its antibacterial properties.

Current Trends and Prospects for Application of Green Synthesized Metal Nanoparticles in Cancer and COVID-19 Therapies

Cancer and COVID-19 have been deemed as world health concerns due to the millions of lives that they have claimed over the years. Extensive efforts have been made to develop sophisticated, site-specific, and safe strategies that can effectively diagnose, prevent, manage, and treat these diseases. These strategies involve the implementation of metal nanoparticles and metal oxides such as gold, silver, iron oxide, titanium oxide, zinc oxide, and copper oxide, formulated through nanotechnology as alternative anticancer or antiviral therapeutics or drug delivery systems. This review provides a perspective on metal nanoparticles and their potential application in cancer and COVID-19 treatments. The data of published studies were critically analysed to expose the potential therapeutic relevance of green synthesized metal nanoparticles in cancer and COVID-19. Although various research reports highlight the great potential of metal and metal oxide nanoparticles as alternative nanotherapeutics, issues of nanotoxicity, complex methods of preparation, biodegradability, and clearance are lingering challenges for the successful clinical application of the NPs. Thus, future innovations include fabricating metal nanoparticles with eco-friendly materials, tailor making them with optimal therapeutics for specific disease targeting, and in vitro and in vivo evaluation of safety, therapeutic efficiency, pharmacokinetics, and biodistribution.

Current status of silica-based nanoparticles as therapeutics and its potential as therapies against viruses

In the past decade, interest in nanoparticles for clinical indications has been steadily gaining traction. Most recently, Lipid Nanoparticles (LNP) have been used successfully to construct the SARS-CoV-2 mRNA vaccines for rapid pandemic response. Similarly, silica is another nanomaterial which holds much potential to create nanomedicines against pathogens of interest. One major advantage of silica-based nanoparticles is its crystalline and highly ordered structure, which can be specifically tuned to achieve the desired properties needed for clinical applications. Increasingly, clinical research has shown the potential of silica nanoparticles not only as an antiviral, but also its ability as a delivery system for antiviral small molecules and vaccines against viruses. Silica has an excellent biosafety profile and has been tested in several early phase clinical trials since 2012, demonstrating good tolerability and minimal reported side effects. In this review, we discuss the clinical development of silica nanoparticles to date and identify the gaps and potential pitfalls in its path to clinical translation.

Waste treatment innovation for infusion bottles using soil solution

The amount of medical waste, especially infusion bottles, is a problem for environmental pollution. Improper management of infusion bottle waste can have an impact on disease transmission. The medical waste treatment used high technology and high costs will be a financial burden, so simple and effective treatment innovations is needed. This study uses an experimental method of removing bacteria from infusion bottles using a mixture of water and Andoso soil as a solution for washing infusion bottle waste. The soil solution concentration used in washing was 45% with a contact time of 2 minutes. The experiment was carried out with two repetitions. The treatment effect on decreasing the number of bacteria using a multiple linear regression mathematical model. The results showed that the disinfection process of bacterial-contaminated infusion bottles using water required rinsing up to six times, whereas using 45% andosol soil solution only rinsed once. The effectiveness of the disinfection of infusion bottles contaminated with bacteria using soil solution reduces the number of bacteria by 98%.

Nanobionics: From plant empowering to the infectious disease treatment

Infectious diseases (ID) are serious threats against the global health and socio-economic conditions. Vaccination usually plays a key role in disease prevention, however, insufficient efficiency or immunogenicity may be quite challenging. Using the advanced vectors for delivery of vaccines with suitable efficiency, safety, and immune-modulatory activity, and tunable characteristics could be helpful, but there are no systematic reviews confirming the capabilities of the vaccine delivery systems for covering various types of pathogens. Furthermore, high rates of the infections, transmission, and fatal ratio and diversity of the pathogens and infection mechanisms may negatively influence vaccine effectiveness. The absence of highly-effective antibiotics against the resistant strains of bacteria and longevity of antibiotic testing have provoked increasing needs towards the application of more accurate and specific theranostic strategies including the nanotechnology-based ones. Nanobionics which is based on the charge storage and transport in the molecular structures, could be of key value in the molecular diagnostic tests and highly-specific electro-analytical methods or devices. Such devices based on the early disease diagnostics might be of critical significance against various types of diseases. This article highlights the significance of nanobionics against ID.

Antiviral drug research for Japanese encephalitis: an updated review

Japanese encephalitis (JE) caused by the Japanese encephalitis virus (JEV) is one of Asia's most common viral encephalitis. JEV is a flavivirus, common in rural and sub-urban regions of Asian countries. Although only 1% of JEV-infected individuals develop JE, there is a 20-30% chance of death among these individuals and possible neurological sequelae post-infection. No licensed anti-JE drugs are currently available, despite extensive efforts to develop them. Literature search was performed using databases such as PubMed Central, Google Scholar, Wiley Online Library, etc. using keywords such as Japanese encephalitis virus, antiviral drugs, antiviral drug screening, antiviral drug targets, etc. From around 230 papers/abstracts and research reviews retrieved and reviewed for this study, approximately 180 most relevant and important ones have been cited. Different approaches in drug testing and various antiviral drug targets explored so far have been thoroughly searched from the literature and compiled, besides addressing the future perspectives of the antiviral drug development strategies. Although the development of effective anti-JE drugs is an urgent issue, only supportive care is currently available. Recent advancements in understanding the biology of infection and new drug targets have been promising improvements. Despite hindrances such as the unavailability of a proper drug delivery system or a treatment regimen irrespective of the stage of infection, several promising anti-JE candidate molecules are in different phases of clinical trials. Nonetheless, efficient therapy against JEV is expected to be achieved with drug combinations and a highly targeted drug delivery system soon.

Nanotechnology Applications of Flavonoids for Viral Diseases

Recent years have witnessed the emergence of several viral diseases, including various zoonotic diseases such as the current pandemic caused by the Severe Acute Respiratory Syndrome Coronavirus 2 (SARS-CoV-2). Other viruses, which possess pandemic-causing potential include avian flu, Ebola, dengue, Zika, and Nipah virus, as well as the re-emergence of SARS (Severe Acute Respiratory Syndrome) and MERS (Middle East Respiratory Syndrome) coronaviruses. Notably, effective drugs or vaccines against these viruses are still to be discovered. All the newly approved vaccines against the SARS-CoV-2-induced disease COVID-19 possess real-time possibility of becoming obsolete because of the development of ‘variants of concern’. Flavonoids are being increasingly recognized as prophylactic and therapeutic agents against emerging and old viral diseases. Around 10,000 natural flavonoid compounds have been identified, being phytochemicals, all plant-based. Flavonoids have been reported to have lesser side effects than conventional anti-viral agents and are effective against more viral diseases than currently used anti-virals. Despite their abundance in plants, which are a part of human diet, flavonoids have the problem of low bioavailability. Various attempts are in progress to increase the bioavailability of flavonoids, one of the promising fields being nanotechnology. This review is a narrative of some anti-viral dietary flavonoids, their bioavailability, and various means with an emphasis on the nanotechnology system(s) being experimented with to deliver anti-viral flavonoids, whose systems show potential in the efficient delivery of flavonoids, resulting in increased bioavailability.

Nanotechnology as a tool for detection and treatment of arbovirus infections

Arboviruses are medically important viruses that cause high rates of infection all over the world. In addition, the severity of the symptoms and the inadequate diagnostic methods represent a challenge far beyond eradicating the vector. The lack of specific treatments for arbovirus infections reflects the imminent need for new research for safe and efficient medicines to treat these infections. Nanotechnology is an innovative approach currently used as a platform for developing new treatments, thus improving the biopharmaceutical properties of drugs. It can also be applied to the development of diagnostic devices, improving their detection capacity. The purpose of this paper is to review recent research on the use of nanotechnology for developing new treatments and detection devices for arbovirus infections. Interestingly, it was found that only a few studies report on the use of nanotechnology to treat arbovirus infections and that most of these reports focus on the fabrication of diagnostic tools. Also, some papers report on the use of nanotechnology for the development of vaccines, which in association with mosquito eradication programs could effectively reduce the high rates of infections by these viruses.

A proposed insight into the anti-viral potential of metallic nanoparticles against novel coronavirus disease-19 (COVID-19)

BACKGROUND

Over the last ten months since December 2019, the world has faced infectious emerging novel coronavirus disease-2019 (COVID-19) outbreaks that had a massive global impact affecting over 185 countries.

MAIN BODY

Emerging novel COVID-19 is a global health emergency on a pandemic scale that represents a terror to human health through its ability to escape anti-viral measures. Such viral infections impose a great socioeconomic burden, besides global health challenges. This imposes a pressing need for the development of anti-viral therapeutic agents and diagnostic tools that demonstrate multifunctional, target-specific, and non-toxic properties. Nanotheranostics is regarded as a promising approach for the management of different viral infections. Nanotheranostics facilitates targeted drug-delivery of anti-viral therapeutics as well as contributing to the development of diagnostic systems. Multifunctional metallic nanoparticles (NPs) have emerged as innovative theranostic agents that enable sustainable treatment and effective diagnosis. Here we have reviewed current advances in the use of theranostic metallic NPs to fight against COVID-19, and discussed the application as well as limitations associated with nanotechnology-based theranostic approaches.

CONCLUSION

This review verified the potential use of some metal-based NPs as anti-viral nanotheranostic agents. Metal-based NPs could act as carriers that enable the sustainable and targeted delivery of active anti-viral molecules, or as diagnostic agents that allow rapid and sensitive diagnosis of viral infections.

Nanotheranostics against COVID-19: From multivalent to immune-targeted materials

Destructive impacts of COVID-19 pandemic worldwide necessitates taking more appropriate measures for mitigating virus spread and development of the effective theranostic agents. In general, high heterogeneity of viruses is a major challenging issue towards the development of effective antiviral agents. Regarding the coronavirus, its high mutation rates can negatively affect virus detection process or the efficiency of drugs and vaccines in development or induce drug resistance. Bioengineered nanomaterials with suitable physicochemical characteristics for site-specific therapeutic delivery, highly-sensitive nanobiosensors for detection of very low virus concentration, and real-time protections using the nanorobots can provide roadmaps towards the imminent breakthroughs in theranostics of a variety of diseases including the COVID-19. Besides revolutionizing the classical disinfection procedures, state-of-the-art nanotechnology-based approaches enable providing the analytical tools for accelerated monitoring of coronavirus and associated biomarkers or drug delivery towards the pulmonary system or other affected organs. Multivalent nanomaterials capable of interaction with multivalent pathogens including the viruses could be suitable candidates for viral detection and prevention of further infections. Besides the inactivation or destruction of the virus, functionalized nanoparticles capable of modulating patient's immune response might be of great significance for attenuating the exaggerated inflammatory reactions or development of the effective nanovaccines and medications against the virus pandemics including the COVID-19.

Anti-Influenza Strategies Based on Nanoparticle Applications

Influenza virus has the potential for being one of the deadliest viruses, as we know from the pandemic's history. The influenza virus, with a constantly mutating genome, is becoming resistant to existing antiviral drugs and vaccines. For that reason, there is an urgent need for developing new therapeutics and therapies. Despite the fact that a new generation of universal vaccines or anti-influenza drugs are being developed, the perfect remedy has still not been found. In this review, various strategies for using nanoparticles (NPs) to defeat influenza virus infections are presented. Several categories of NP applications are highlighted: NPs as immuno-inducing vaccines, NPs used in gene silencing approaches, bare NPs influencing influenza virus life cycle and the use of NPs for drug delivery. This rapidly growing field of anti-influenza methods based on nanotechnology is very promising. Although profound research must be conducted to fully understand and control the potential side effects of the new generation of antivirals, the presented and discussed studies show that nanotechnology methods can effectively induce the immune responses or inhibit influenza virus activity both in vitro and in vivo. Moreover, with its variety of modification possibilities, nanotechnology has great potential for applications and may be helpful not only in anti-influenza but also in the general antiviral approaches.

Cytotoxicity Produced by Silicate Nanoplatelets: Study of Cell Death Mechanisms

Nano-silicate platelets (NSP), an exfoliated product from natural clays, have been validated for biosafety and as an effective supplement to alleviate mycotoxicosis. Since NSP induced noticeable cell death, we therefore investigated further the mechanism of cytotoxicity caused by NSP. Exposure to NSP impaired membrane integrity and caused cell death in a dose-dependent manner. Reactive oxygen species (ROS) generation other than of NADH oxidase origin, and subcellular interactions by internalized NSP also contributed to NSP-induced cell death. NSP persistently provoked receptor-interacting protein 1 Ser/Thr (RIP1) kinase and caspase 6 and 3/7 activation without altering caspase 8 activity and induced evident chromatolysis of necrosis in the later stage. These events proceeded along with increased ER stress and mitochondrial permeability, to final Cyt-C (Cytochrome C) release and AIF (apoptosis inducing factor) translocation, a hallmark of cell necroptosis. Fluorescent probing further manifested NSP traffic, mostly adherence on the cell surfaces, or via internalization, being compartmentalized in the nuclei, cytosols, and mitochondria. Pharmacological approaches with specific inhibitors suggested that endocytosis and particularly RIP1 kinase provocation mediate NSP-induced cell death independent of caspase activation. In conclusion, the necroptotic process contributes to most of the cell death induced by NSP due to membrane interactions/impaired integrity, ROS generation, and subcellular interactions by internalized NSP.

Can nanotechnology help in the fight against COVID-19?

INTRODUCTION

The current COVID-19 pandemic caused by the SARS-CoV-2 virus demands the development of strategies not only to detect or inactivate the virus, but to treat it (therapeutically and prophylactically). COVID-19 is not only a critical threat for the population with risk factors, but also generates a dramatic economic impact in terms of morbidity and the overall interruption of economic activities.

AREAS COVERED

Advanced materials are the basis of several technologies that could diminish the impact of COVID-19: biosensors might allow early virus detection, nanosized vaccines are powerful agents that could prevent viral infections, and nanosystems with antiviral activity could bind the virus for inactivation or destruction upon application of an external stimulus. Herein all these methods are discussed under the light of cutting-edge technologies and the previously reported prototypes targeting enveloped viruses similar to SARS-CoV-2. This analysis was derived from an extensive scientific literature search (including pubmed) performed on April 2020.

EXPERT OPINION

Perspectives on how biosensors, vaccines, and antiviral nanosystems can be implemented to fight COVID-19 are envisioned; identifying the approaches that can be implemented in the short term and those that deserve long term research to cope with respiratory viruses-related pandemics in the future.

Nanoformulations: A Valuable Tool in the Therapy of Viral Diseases Attacking Humans and Animals

Various viruses can be considered as one of the most frequent causes of human diseases, from mild illnesses to really serious sicknesses that end fatally. Numerous viruses are also pathogenic to animals and plants, and many of them, mutating, become pathogenic also to humans. Several cases of affecting humans by originally animal viruses have been confirmed. Viral infections cause significant morbidity and mortality in humans, the increase of which is caused by general immunosuppression of the world population, changes in climate, and overall globalization. In spite of the fact that the pharmaceutical industry pays great attention to human viral infections, many of clinically used antivirals demonstrate also increased toxicity against human cells, limited bioavailability, and thus, not entirely suitable therapeutic profile. In addition, due to resistance, a combination of antivirals is needed for life-threatening infections. Thus, the development of new antiviral agents is of great importance for the control of virus spread. On the other hand, the discovery and development of structurally new antivirals represent risks. Therefore, another strategy is being developed, namely the reformulation of existing antivirals into nanoformulations and investigation of various metal and metalloid nanoparticles with respect to their diagnostic, prophylactic, and therapeutic antiviral applications. This chapter is focused on nanoscale materials/formulations with the potential to be used for the treatment or inhibition of the spread of viral diseases caused by human immunodeficiency virus, influenza A viruses (subtypes H3N2 and H1N1), avian influenza and swine influenza viruses, respiratory syncytial virus, herpes simplex virus, hepatitis B and C viruses, Ebola and Marburg viruses, Newcastle disease virus, dengue and Zika viruses, and pseudorabies virus. Effective antiviral long-lasting and target-selective nanoformulations developed for oral, intravenous, intramuscular, intranasal, intrarectal, intravaginal, and intradermal applications are discussed. Benefits of nanoparticle-based vaccination formulations with the potential to secure cross protection against divergent viruses are outlined as well.

Glutathione-Capped Ag2S Nanoclusters Inhibit Coronavirus Proliferation through Blockage of Viral RNA Synthesis and Budding

Development of novel antiviral reagents is of great importance for the control of virus spread. Here, Ag₂S nanoclusters (NCs) were proved for the first time to possess highly efficient antiviral activity by using porcine epidemic diarrhea virus (PEDV) as a model of coronavirus. Analyses of virus titers showed that Ag₂S NCs significantly suppressed the infection of PEDV by about 3 orders of magnitude at the noncytotoxic concentration at 12 h postinfection, which was further confirmed by the expression of viral proteins. Mechanism investigations indicated that Ag₂S NCs treatment inhibits the synthesis of viral negative-strand RNA and viral budding. Ag₂S NCs treatment was also found to positively regulate the generation of IFN-stimulating genes (ISGs) and the expression of proinflammation cytokines, which might prevent PEDV infection. This study suggest the novel underlying of Ag₂S NCs as a promising therapeutic drug for coronavirus.

Design, synthesis, in silico and in vitro antimicrobial screenings of novel 1,2,4-triazoles carrying 1,2,3-triazole scaffold with lipophilic side chain tether

BACKGROUND

1,2,4-Triazoles and 1,2,3-triazoles have gained significant importance in medicinal chemistry.

RESULTS

This study describes a green, efficient and quick solvent free click synthesis of new 1,2,3-triazole-4,5-diesters carrying a lipophilic side chain via 1,3-dipolar cycloaddition of diethylacetylene dicarboxylate with different surfactant azides. Further structural modifications of the resulting 1,2,3-triazole diesters to their corresponding 1,2,4-triazole-3-thiones via multi-step synthesis has been also investigated. The structures of the newly designed triazoles have been elucidated based on their analytical and spectral data. These compounds were evaluated for their antimicrobial activities. Relative to the standard antimicrobial agents, derivatives of 1,2,3-triazole-bis-4-amino-1,2,4-triazole-3-thiones were the most potent antimicrobial agents with compound 7d demonstrating comparable antibacterial and antifungal activities against all tested microorganisms. Further, the selected compounds were studied for docking using the enzyme, Glucosamine-6-phosphate synthase.

CONCLUSIONS

The in silico study reveals that all the synthesized compounds had shown good binding energy toward the target protein ranging from - 10.49 to - 5.72 kJ mol-1 and have good affinity toward the active pocket, thus, they may be considered as good inhibitors of GlcN-6-P synthase.

Role of metal and metal oxide nanoparticles as diagnostic and therapeutic tools for highly prevalent viral infections

Nanotechnology is increasingly playing important roles in various fields including virology. The emerging use of metal or metal oxide nanoparticles in virus targeting formulations shows the promise of improved diagnostic or therapeutic ability of the agents while uniquely enhancing the prospects of targeted drug delivery. Although a number of nanoparticles varying in composition, size, shape, and surface properties have been approved for human use, the candidates being tested or approved for clinical diagnosis and treatment of viral infections are relatively less in number. Challenges remain in this domain due to a lack of essential knowledge regarding the in vivo comportment of nanoparticles during viral infections. This review provides a broad overview of recent advances in diagnostic, prophylactic and therapeutic applications of metal and metal oxide nanoparticles in human immunodeficiency virus, hepatitis virus, influenza virus and herpes virus infections. Types of nanoparticles commonly used and their broad applications have been explained in this review.

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

Background

Healthcare-acquired infections by pathogenic microorganisms including viruses represent significant health concern worldwide. Next to direct transmission from person-to-person also indirect transmission from contaminated surfaces is well documented and important route of infections. Here, we tested antiviral properties of hybrid coating containing silver, copper and zinc cations that was previously shown to be effective against pathogenic bacteria including methicillin-resistant Staphylococcus aureus. Hybrid coatings containing silver, copper and zinc cations were prepared through radical polymerization via sol-gel method and applied on glass slides or into the wells of polymethylmethacrylate plates. A 10 μl droplet of several viruses such as human immunodeficiency virus type 1 (HIV-1), influenza, dengue virus, herpes simplex virus, and coxsackievirus was added to coated and uncoated slides or plates, incubated usually from 5 to 240 min and followed by titer determination of recovered virus.

Results

Scanning electron microscopy analysis showed better adhesion of coatings on glass surfaces, which resulted in 99.5–100 % HIV-1 titer reduction (3.1 ± 0.8 log₁₀TCID₅₀, n = 3) already after 20 min of exposure to coatings, than on coated polymethylmethacrylate plates with 75–100 % (1.7 ± 1.1 log₁₀TCID₅₀, n = 3) and 98–100 % (2.3 ± 0.5 log₁₀TCID₅₀, n = 3) HIV-1 titer reduction after 20 and 120 min of exposure, respectively. Slower virucidal kinetics was observed with other enveloped viruses, where 240 min exposure to coated slides lead to 97 % (dengue), 100 % (herpes simplex) and 77 % (influenza) reduction in virus titers. Interestingly, only marginal reduction in viral titer after 240 min of exposure was noticed for non-enveloped coxsackie B3 virus.

Conclusions

Our hybrid coatings showed virucidal activity against HIV and other enveloped viruses thus providing further findings towards development of broad-spectrum antimicrobial coating suitable for surfaces in healthcare settings.

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

Interactions between nanoparticles and viruses have attracted increasing attention due to the antiviral activity of nanoparticles and the resulting possibility to be employed as biomedical interventions. In this contribution, we developed a very simple route to prepare uniform and stable silver nanoparticles (AgNPs) with antiviral properties by using curcumin, which is a member of the ginger family isolated from rhizomes of the perennial herb Curcuma longa and has a wide range of biological activities like antioxidant, antifungal, antibacterial and anti-inflammatory effects, and acts as reducing and capping agents in this synthetic route. The tissue culture infectious dose (TCID50) assay showed that the curcumin modified silver nanoparticles (cAgNPs) have a highly efficient inhibition effect against respiratory syncytial virus (RSV) infection, giving a decrease of viral titers about two orders of magnitude at the concentration of cAgNPs under which no toxicity was found to the host cells. Mechanism investigations showed that cAgNPs could prevent RSV from infecting the host cells by inactivating the virus directly, indicating that cAgNPs are a novel promising efficient virucide for RSV.

Antiviral Activity of Graphene Oxide: How Sharp Edged Structure and Charge Matter

Graphene oxide and its derivatives have been widely explored for their antimicrobial properties due to their high surface-to-volume ratios and unique chemical and physical properties. However, little information is available on their effects on viruses. In this study, we report the broad-spectrum antiviral activity of GO against pseudorabies virus (PRV, a DNA virus) and porcine epidemic diarrhea virus (PEDV, an RNA virus). Our results showed that GO significantly suppressed the infection of PRV and PEDV for a 2 log reduction in virus titers at noncytotoxic concentrations. The potent antiviral activity of both GO and rGO can be attributed to the unique single-layer structure and negative charge. First, GO exhibited potent antiviral activity when conjugated with PVP, a nonionic polymer, but not when conjugated with PDDA, a cationic polymer. Additionally, the precursors Gt and GtO showed much weaker antiviral activity than monolayer GO and rGO, suggesting that the nanosheet structure is important for antiviral properties. Furthermore, GO inactivated both viruses by structural destruction prior to viral entry. The overall results suggest the potential of graphene oxide as a novel promising antiviral agent with a broad and potent antiviral activity.

Potential chemotherapeutic targets for Japanese encephalitis: current status of antiviral drug development and future challenges

INTRODUCTION

Japanese encephalitis (JE) remains a public health threat in Asia. Although several vaccines have been licensed, ∼ 67,900 cases of the disease are estimated to occur annually, probably because the vaccine coverage is low. Therefore, effective antiviral drugs are required to control JE. However, no licensed anti-JE drugs are available, despite extensive efforts to develop them.

AREAS COVERED

We provide a general overview of JE and JE virus, including its transmission cycle, distribution, structure, replication machinery, immune evasion mechanisms and vaccines. The current situation in antiviral drug development is then reviewed and future perspectives are discussed.

EXPERT OPINION

Although the development of effective anti-JE drugs is an urgent issue, only supportive care is currently available. Recent progress in our understanding of the viral replication machinery and immune evasion strategies has identified new targets for anti-JE drug development. To date, most candidate drugs have only been evaluated in single-drug formulations, and efficient drug delivery to the CNS has virtually not been considered. However, an effective anti-JE treatment is expected to be achieved with multiple-drug formulations and a targeted drug delivery system in the near future.