Virucidal Activity Research Articles

Multifunctional polymeric guanidine and hydantoin halamines with broad biocidal activity

Prolonged and excessive use of biocides during the coronavirus disease era calls for incorporating new antiviral polymers that enhance the surface design and functionality for existing and potential future pandemics. Herein, we investigated previously unexplored polyamines with nucleophilic biguanide, guanidine, and hydantoin groups that all can be halogenated leading to high contents of oxidizing halogen that enables enhancement of the biocidal activity. Primary amino groups can be used to attach poly(N-vinylguanidine) (PVG) and poly(allylamine-co-4-aminopyridine-co-5-(4-hydroxybenzylidene)hydantoin) (PAH) as well as a broad-spectrum commercial biocide poly(hexamethylene biguanide) (PHMB) onto a solid support. Halogenation of polymer suspensions was conducted through in situ generation of excess hypobromous acid (HBrO) from bromine and sodium hydroxide or by sodium hypochlorite in aqueous solutions, resulting in N-halamines with high contents of active > N-Br or > N-Cl groups. The virucidal activity of the polymers against human respiratory coronavirus HCoV-229E increased dramatically with their halogenation. Brominated PHMB-Br showed activation activity value > 5 even at 1 mg/L, and complete virus inhibition was observed with either PHMB-Br or PAH-Br at 10 mg/mL. Brominated PVG-Br and PAH-Br possessed fungicidal activity against C. albicans, while PHMB was fungistatic. PHMB, PHMB-Br and PAH polymers demonstrated excellent bactericidal activity against the methicillin-resistant S. aureus and vancomycin-resistant E. faecium. Brominated polymers (PHMB-Br, PVG-Br, PAH-Br) were not toxic to the HeLa monolayers, indicating acceptable biocompatibility to cultured human cells. With these features, the N-halamine polymers of the present study are a worthwhile addition to the arsenal of biocides and are promising candidates for development of non-leaching coatings.

Virucidal activity of chlorine dioxide in combination with acetic acid or citric acid and a surfactant, in presence of interfering substances, against polio-, adeno- and murine norovirus in suspension-, carrier- and four-field tests.

The aim of the study was to investigate whether the virucidal effectiveness of chlorine dioxid against adenovirus and murine norovirus can be improved by combining it with carboxylic acids and surfactants. The virucidal efficacy against polio-, adeno- and murine norovirus has been tested in presence of interfering substances in the quantitative suspension test according to EN 14476, the carrier test without mechanical action according to EN 16777, and in the four-field test according to EN 16615.Three chlorine-dioxide-based surface disinfectants were tested: a two-component cleaning disinfectant concentrate for large surfaces, a ready-to-use (RTU) foam, and an RTU gel. Cleaning and disinfecting preparations based on chlorine dioxide, applied at various concentrations, in combination with acetic acid or citric acid and surfactants, are virucidally active against polio-, adeno-, and norovirus after an exposure time of 5 minutes in presence of interfering substances.

Physicochemistry, Nutritional, and Therapeutic Potential of Ficus carica - A Promising Nutraceutical.

In an era where synthetic supplements have raised concerns regarding their effects on human health, Ficus carica has emerged as a natural alternative rich in polyphenolic compounds with potent therapeutic properties. Various studies on F. carica focusing on the analysis and validation of its pharmacological and nutritional properties are emerging. This paper summarizes present data and information on the phytochemical, nutritional values, therapeutic potential, as well as the toxicity profile of F. carica. An extensive search was conducted from various databases, including PubMed, ScienceDirect, Scopus, and Google Scholar. A total of 126 studies and articles related to F. carica that were published between 1999 and 2023 were included in this review. Remarkably, F. carica exhibits a diverse array of advantageous effects, including, but not limited to, antioxidant, anti-neurodegenerative, antimicrobial, antiviral, anti-inflammatory, anti-arthritic, antiepileptic, anticonvulsant, anti-hyperlipidemic, anti-angiogenic, antidiabetic, anti-cancer, and antimutagenic properties. Among the highlights include that antioxidants from F. carica were demonstrated to inhibit cholinesterase, potentially protecting neurons in Alzheimer's disease and other neurodegenerative conditions. The antimicrobial activities of F. carica were attributed to its high flavonoids and terpenoids content, while its virucidal action through the inhibition of DNA and RNA replication was postulated due to its triterpenes content. Inflammatory and arthritic conditions may also benefit from its anti-inflammatory and anti-arthritic properties through the modulation of various signalling proteins. Studies have also shown that F. carica extracts were generally safe and exhibit low toxicity profile, although more research in this aspect is required, specifically its effects on the skin. In conclusion, this study highlights the potential of F. carica as a valuable natural therapeutic agent and dietary supplement. However, continued exploration on F. carica's safety and efficacy is still required prior to embarking on clinical trials, as its role in personalized nutrition and medication will open a new paradigm to improve health outcomes.

Incorporação de extratos de Cordia glabrata (Mart.) A.DC. em microemulsões e suas potenciais atividades antioxidante, fotoprotetora e virucida

Extracts of species from the Cordia genus have been reported with potential biological activities, such as antioxidant, antimicrobial, antiviral, and antiparasitic. The aim of this study was to develop microemulsions containing ethanolic extracts of C. glabrata leaves and to evaluate their stability and biological activities. The five developed microemulsions presented physicochemical stability and presented Newtonian behavior when submitted to rheological analysis. The diameter values of the globules ranged between 225.74 and 273.33 nm and the zeta potential of the formulations remained between -22.40 and -25.08. All phenolic acids of the extract, quantified by HPLC, showed consistency after being microemulsified. The EC50 values for the antioxidant activity by the DPPH scavenging method ranged between 38.13 and 45.54 µgmL-1, and between 34.46 and 39.60 mM for the ABTS+ scavenging method. The virucidal activity presented a CV50 <0.195 µgmL-1 and a selectivity index greater than 20. The photoprotection results ranged between 2.14 to 2.84. The study revealed stable microemulsions and potentiation of the antioxidant effect in the microemulsified extracts.

Leveraging virucidal potential of an anti-microbial coating agent to mitigate fomite transmission of respiratory viruses

In the wake of the COVID-19 pandemic, respiratory tract infections have emerged as a significant global threat, yet their impact on public health was previously underappreciated. This study investigated the antiviral efficacy of the nano-coating agent BARRIER90, composed of silicon-quaternary ammonium compound and a naturally derived biopolymer, against three distinct respiratory viruses: Influenza A (H1N1), Adenovirus Type 1, and Enterovirus-Coxsackie B1. BARRIER90 exhibited robust and sustained virucidal activity, persisting up to 90 days post-coating, against the enveloped virus, Influenza A, with significant reduction in viral plaques. Contrastingly, its efficacy against non-enveloped viruses revealed transient activity against Enterovirus-Coxsackie B1, with almost no antiviral activity observed against Adenovirus Type 1. These findings indicate the potential of antimicrobial coatings in mitigating viral transmission through contaminated surfaces (fomites), which harbour pathogenic viruses for longer periods. Antimicrobial coatings may facilitate infection control in various settings, including healthcare facilities and shared workspaces.

Prospective Antiviral Effect of Ulva lactuca Aqueous Extract against COVID-19 Infection.

Marine algal extracts exhibit a potent inhibitory effect against several enveloped and non-enveloped viruses. The infection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) has several adverse effects, including an increased mortality rate. The anti-COVID-19 agents are still limited; this issue requires exploring novel, effective anti-SARS-CoV-2 therapeutic approaches. This study investigated the antiviral activity of an aqueous extract of Ulva lactuca, which was collected from the Gulf of Suez, Egypt. The aqueous extract of Ulva lactuca was characterized by high-performance liquid chromatography (HPLC), Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), and Energy Dispersive X-ray (EDX) analyses. According to the HPLC analysis, the extract comprises several sugars, mostly rhamnose (32.88%). The FTIR spectra showed numerous bands related to the functional groups. EDX analysis confirmed the presence of different elements, such as oxygen (O), carbon (C), sulfur (S), magnesium (Mg), potassium (K), calcium (Ca), and sodium (Na), with different concentrations. The aqueous extract of U. lactuca (0.0312 mg/mL) exhibited potent anti-SARS-CoV-2 activity via virucidal activity, inhibition of viral replication, and interference with viral adsorption (% inhibitions of 64%, 33.3%, and 31.1%, respectively). Consequently, ulvan could be a promising compound for preclinical study in the drug development process to combat SARS-CoV-2.

Broad-spectrum virucidal activity of a hydroalcoholic extract of grape pomace

Grape pomace is a by-product of winemaking often disposed of before full exploitation. Indeed, this natural product holds great potential for sustainable utilization. In this study, dried grape pomace was reprocessed to assess its potential as a valuable source of antiviral metabolites. The antiviral activity of the extract was assessed against Herpes Simplex virus type-2, Feline Calicivirus, Coxsackievirus B5, and Influenza type-A virus, revealing potent broad virucidal effect. Indeed, it abolished viral infection when the extract was incubated with viruses before or during infection, whereas no significant toxic effects were observed up to 3 mg/mL.UHPLC-MS/MS analysis identified quercetin, gallic acid, and ethyl gallate as its primary constituents. These did not fully account for its virucidal action, suggesting the presence of additional active components and/or synergistic effect of more compounds.Thus, grape pomace may be exploited as a sustainable source for the preparation of environmentally friendly broad-spectrum virucidal disinfectants.

Piercing of the Human Parainfluenza Virus by Nanostructured Surfaces.

This paper presents a comprehensive experimental and theoretical investigation into the antiviral properties of nanostructured surfaces and explains the underlying virucidal mechanism. We used reactive ion etching to fabricate silicon (Si) surfaces featuring an array of sharp nanospikes with an approximate tip diameter of 2 nm and a height of 290 nm. The nanospike surfaces exhibited a 1.5 log reduction in infectivity of human parainfluenza virus type 3 (hPIV-3) after 6 h, a substantially enhanced efficiency, compared to that of smooth Si. Theoretical modeling of the virus-nanospike interactions determined the virucidal action of the nanostructured substrata to be associated with the ability of the sharp nanofeatures to effectively penetrate the viral envelope, resulting in the loss of viral infectivity. Our research highlights the significance of the potential application of nanostructured surfaces in combating the spread of viruses and bacteria. Notably, our study provides valuable insights into the design and optimization of antiviral surfaces with a particular emphasis on the crucial role played by sharp nanofeatures in maximizing their effectiveness.

A Novel Handrub Tablet Loaded with Pre- and Post-Biotic Solid Lipid Nanoparticles Combining Virucidal Activity and Maintenance of the Skin Barrier and Microbiome.

This study aimed to develop a holobiont tablet with rapid dispersibility to provide regulation of the microbiota, virucidal activity, and skin barrier protection. A 23 factorial experiment was planned to define the best formulation for the development of the base tablet, using average weight, hardness, dimensions, swelling rate, and disintegration time as parameters to be analyzed. To produce holobiont tablets, the chosen base formulation was fabricated by direct compression of prebiotics, postbiotics, and excipients. The tablets also incorporated solid lipid nanoparticles containing postbiotics that were obtained by high-pressure homogenization and freeze-drying. The in vitro virucidal activity against alpha-coronavirus particles (CCoV-VR809) was determined in VERO cell culture. In vitro analysis, using monolayer cells and human equivalent skin, was performed by rRTq-PCR to determine the expression of interleukins 1, 6, 8, and 17, aquaporin-3, involucrin, filaggrin, FoxO3, and SIRT-1. Antioxidant activity and collagen-1 synthesis were also performed in fibroblast cells. Metagenomic analysis of the skin microbiome was determined in vivo before and after application of the holobiont tablet, during one week of continuous use, and compared to the use of alcohol gel. Samples were analyzed by sequencing the V3-V4 region of the 16S rRNA gene. A handrub tablet with rapid dispersibility was developed for topical use and rinse off. After being defined as safe, the virucidal activity was found to be equal to or greater than that of 70% alcohol, with a reduction in interleukins and maintenance or improvement of skin barrier gene markers, in addition to the reestablishment of the skin microbiota after use. The holobiont tablets were able to improve the genetic markers related to the skin barrier and also its microbiota, thereby being more favorable for use as a hand sanitizer than 70% alcohol.

SARS-CoV-2 Fusion Peptide Conjugated to a Tetravalent Dendrimer Selectively Inhibits Viral Infection.

Fusion is a key event for enveloped viruses, through which viral and cell membranes come into close contact. This event is mediated by viral fusion proteins, which are divided into three structural and functional classes. The severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) spike protein belongs to class I fusion proteins, characterized by a trimer of helical hairpins and an internal fusion peptide (FP), which is exposed once fusion occurs. Many efforts have been directed at finding antivirals capable of interfering with the fusion mechanism, mainly by designing peptides on the two heptad-repeat regions present in class I viral fusion proteins. Here, we aimed to evaluate the anti-SARS-CoV-2 activity of the FP sequence conjugated to a tetravalent dendrimer through a classical organic nucleophilic substitution reaction (SN2) using a synthetic bromoacetylated peptide mimicking the FP and a branched scaffold of poly-L-Lysine functionalized with cysteine residues. We found that the FP peptide conjugated to the dendrimer, unlike the monomeric FP sequence, has virucidal activity by impairing the attachment of SARS-CoV-2 to cells. Furthermore, we found that the peptide dendrimer does not have the same effects on other coronaviruses, demonstrating that it is selective against SARS-CoV-2.

Rapid and efficient inactivation of viruses in seawater by LIG electrodes

Water-borne viral diseases are a significant concern for public health. In particular, they threaten the health of people and animals in countries that lack proper water treatment facilities. Novel water treatment technology may efficiently improve water quality and prevent the spread of waterborne viral pathogens. Laser-induced graphene (LIG) has been shown to inactivate viruses and bacteria with its photothermal properties, electrochemical reaction, and rough surface texture. However, LIG's activity to prevent virus transmission via contaminated water has not been fully explored. Here, we demonstrated that enveloped and non-enveloped viruses in seawater could be rapidly inactivated by LIG technology. After being activated by 3 V of electricity, the LIG electrodes inactivated both types of viruses spiked in water within 30 min. In addition, the electrolyzed seawater exhibited virucidal effects even after the cessation of the electrical charge. The generation of different oxidants, such as chlorine, chlorine dioxide, and hydrogen peroxide, may play an essential role in the antiviral mechanism of the LIG electrodes. Furthermore, after 10 min of electrolysis, the pH of the seawater dropped from approximately 8–5, which may also have contributed to the virucidal effects of the LIG technology. The virucidal activity of LIG technology highlighted its potential for preventing the spread of viral infections via seawater systems which may have public health implications in areas where seawater is used in the sewage system. It may also have applications in aquaculture, where viral diseases do not have treatments and can cause high fish mortality.

Сравнительная оценка токсичности и вирулицидных свойств дезинфектантов, применяемых при работе с вирусом SARS-CoV-2 в изолированных вирусологических лабораториях

The choice of disinfectants and their combinations for the final disinfection of the premises of «infectious» areas of laboratories of biosafety level 3–4, in which work is carried out with viruses with epidemic potential, is important for reducing the toxic effect of these disinfectants on personnel while maintaining 100?% disinfection efficiency. Purpose of the study: to study the toxicity of disinfectants of different groups for cell culture, to select a toxicity neutralizer, to study the virucidal activity of these disinfectants and their combinations against the SARS-CoV-2 virus. Materials and methods: experimental studies were carried out using the reference strain of coronavirus SARS-CoV-2, namely the hCoV-19/Australia/VIC01/2020 (AUS) strain (Wuhan variant), obtained from the State Collection of Causative Agents of Viral Infectious Diseases and Rickettsial Diseases, functioning on the basis of the Federal Budgetary Institution State Scientific Center for Virology and Biotechnology «Vector» of Rospotrebnadzor. The residual infectious activity of the virus was determined by titrating samples in cell culture. To conduct the research, we used a Vero E6 cell culture obtained from the Collection of Cell Cultures of the Federal Budgetary Institution of Scientific Research Center for Virology and Biochemistry «Vector» of Rospotrebnadzor in the form of a 2-day monolayer with a confluency of 95–100?%. Results. As a result of the studies, experimental data were obtained on the dynamics of the virucidal activity of different groups of disinfectants and their combinations against the SARS-CoV-2 virus. The degree of toxicity of disinfectants for Vero E6 cell culture is shown. Optimal combinations of disinfectants and a 40?% aqueous solution of formaldehyde (hereinafter referred to as formalin) have been selected, increasing its disinfection efficiency at an initial concentration halved, which can be used for final disinfection treatment of the premises of isolated virology laboratories conducting work with the SARS-CoV- coronavirus. Conclusion. The results obtained indicate that when using selected combinations of disinfectants to carry out final disinfection with formaldehyde vapors formed during the evaporation of formaldehyde as a result of its heating, a twofold decrease in the initial concentration of formalin is possible, leading to a decrease in its toxic effect on personnel, while maintaining 100?% efficiency disinfection. Keywords: disinfection, disinfectants, formaldehyde, SARS-CoV-2 coronavirus, disinfection efficiency, cytotoxicity.

Neutrophil Virucidal Activity Against SARS-CoV-2 Is Mediated by Neutrophil Extracellular Traps.

Inflammation in the lungs and other vital organs in COVID-19 is characterized by the presence of neutrophils and a high concentration of neutrophil extracellular traps (NETs), which seems to mediate host tissue damage. However, it is not known whether NETs could have virucidal activity against SARS-CoV-2. We investigated whether NETs could prevent SARS-CoV-2 replication in neutrophils and epithelial cells and what the consequence of NETs degradation would be in K18-humanized ACE2 transgenic mice infected with SARS-CoV-2. Here, by immunofluorescence microscopy, we observed that viral particles colocalize with NETs in neutrophils isolated from patients with COVID-19 or healthy individuals and infected in vitro. The inhibition of NETs production increased virus replication in neutrophils. In parallel, we observed that NETs inhibited virus abilities to infect and replicate in epithelial cells after 24 hours of infection. Degradation of NETs with DNase I prevented their virucidal effect in vitro. Using K18-humanized ACE2 transgenic mice, we observed a higher viral load in animals treated with DNase I. However, the virucidal effect of NETs was not dependent on neutrophil elastase or myeloperoxidase activity. Our results provide evidence of the role of NETosis as a mechanism of SARS-CoV-2 viral capture and inhibition.

Ultraviolet-C light at 222 nm has a high disinfecting spectrum in environments contaminated by infectious pathogens, including SARS-CoV-2.

Ultraviolet light (UV) acts as a powerful disinfectant and can prevent contamination of personal hygiene from various contaminated environments. The 222-nm wavelength of UV-C has a highly effective sterilization activity and is safer than 275-nm UV-C. We investigated the irradiation efficacy of 222-nm UV-C against contaminating bacteria and viruses in liquid and fabric environments. We conducted colony-forming unit assays to determine the number of viable cells and a 50% tissue culture infectious dose assay to evaluate the virus titration. A minimum dose of 27 mJ/cm2 of 222-nm UV-C was required for >95% germicidal activity for gram-negative and -positive bacteria. A 25.1 mJ/cm2 dose could ensure >95% virucidal activity against low-pathogenic avian influenza virus and severe acute respiratory syndrome coronavirus (SARS-CoV-2). In addition, this energy dose of 222-nm UV-C effectively inactivated SARS-CoV-2 variants, Delta and Omicron. These results provide valuable information on the disinfection efficiency of 222-nm UV-C in bacterial and virus-contaminated environments and can also develop into a powerful tool for individual hygiene.

Stability of the Virucidal Activity of Commercial Disinfectants against Avian Influenza Viruses under Different Environmental Conditions.

Highly pathogenic avian influenza viruses (HPAIVs) have caused outbreaks in both domestic and wild birds during the winter seasons in several countries in the Northern Hemisphere, most likely because virus-infected wild ducks overwinter and serve as the primary source of infection for other birds in these countries. Several chemical disinfectants are available to deactivate these viruses outside a living organism. However, their virucidal activity is known to be compromised by various factors, including temperature and contamination with organic matter. Hence, the effectiveness of virucidal activity under winter field conditions is crucial for managing HPAIV outbreaks. To investigate the impact of the winter field conditions on the virucidal activity of disinfectants against AIVs, we assessed the stability of the virucidal activity of seven representative disinfectants that are commercially available for poultry farms in Japan against both LPAIVs and HPAIVs under cold and/or organic contamination conditions. Of the seven disinfectants examined, the ortho-dichlorobenzene/cresol-based disinfectant exhibited the most consistent virucidal activity under winter field conditions, regardless of the virus pathogenicity or subtype tested.

Comparative Study on Phytochemical Composition, Antioxidant, and Anti-HSV-2 Activities of Sambucus nigra L. and Sambucus ebulus L. Extracts

Sambucus nigra (SN) and Sambucus ebulus (SE) are widely used in folk medicine, primarily as antiviral agents for colds and influenza. In the current study, the antiviral activity of extracts of SN and SE fruits, flowers, and leaves were tested against herpes simplex virus type-2 (HSV-2). The HPLC analysis of the investigated extracts revealed the presence of phenolic acids, flavonoids, and anthocyanins. Rutin and chlorogenic acid were the main polyphenol constituents in flower and leaf extracts, whereas anthocyanins were predominant in fruit extracts. The flower extract of SN was characterized by the highest content of rutin and chlorogenic acid—14,232.1 mg/100 g dry weight (DW) and 7086.7 mg/100 g DW, respectively. SN fruit extract revealed the highest antioxidant activity measured using ORAC and HORAC methods—11,443.1 μmol TE/g and 8198.9 μmol GAE/g, respectively. To evaluate cytotoxicity, antiviral, and virucidal activities against HSV-2, the MTT assay and method of Reed and Muench were used. The least toxic extracts were PSNFrE and PSEFrE. The maximum tolerable concentration (MTC) of PSNFrE was 2000 μg/mL and the calculated CC50 value for that extract was 3570 μg/mL. The inhibitory activity against virus replication was established for three of the extracts—PSNFlE, PSNLE, and PSNFrE. PSEFrE showed neither activity against virus replication, nor virucidal activity. The data suggest a significant inactivation of more than 98% after 60 min of contact of HSV-2 virions with the PSNFrE applied in MTC. The current study provides evidence that Sambucus nigra reveals anti-HSV-2 activity; however, the most active parts of the species were fruits. Therefore, SN fruits and their extracts can be used as an attendant therapy for HSV-2 viral infections.

Chemical characteristics and biological activity screening of Pistacia lentiscus mastic gum and leaves from Türkiye.

Mastic gum is a resin that is produced by Pistacia lentiscus. It has many traditional uses, dating from ancient times, such as the treatment of gastrointestinal disorders and as a food additive. In this study, the leaves and mastic gum of trees of different ages from Karaburun and the Cesme peninsula in Türkiye were examined chemically and biologically. Flavonoids, and phenolic and fatty acid components were evaluated by a liquid chromatography system coupled with high resolution mass spectrometry (LC-HRMS) and gas chromatography with flame ionization detection (GC-FID). Cytotoxicity was screened against several cancer and healthy cell lines using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyl-2H-tetrazolium bromide (MTT) assay. Inducible nitric oxide synthase (iNOS) inhibition was determined on lipopolysaccharide (LPS)-induced murine macrophage cell line(RAW264.7) cells. Antiviral activity was measured against avian coronavirus using an in ovo virucidal antiviral activity assay. The main phenolic constituents of the gum were found to be salicylic, rosmarinic, and caffeic acids whereas the most abundant compounds detected were flavonoids in the leaf extracts. The most abundant fatty acids in hexane extracts were palmitic and oleic acids. All gum extracts except 3-year-old gum had significant cytotoxic activity on HeLa (IC50 1.74 ± 0.03-4.76 ± 0.95) and PC-3 (0.64 ± 0.25-6.22 ± 1.40) cells. Moreover, reducing virus activity by fivefold or sixfold logarithmically between the range of 5-10 μg g-1 of 30-year-old gum extracts underscored the biological activity. In ovo antiviral activity studies on the P. lentiscus were conducted for the first time. The mastic gum and leaves obtained from P. lentiscus may have strong potential in terms of their chemical content and antiviral and cytotoxic activity. As a consequence of these properties, it is a sustainable, renewable natural resource that can be used as an additive and flavoring in the food and pharmaceutical industries. © 2023 The Authors. Journal of The Science of Food and Agriculture published by John Wiley & Sons Ltd on behalf of Society of Chemical Industry.

Propylene glycol inactivates respiratory viruses and prevents airborne transmission

Viruses are vulnerable as they transmit between hosts, and we aimed to exploit this critical window. We found that the ubiquitous, safe, inexpensive and biodegradable small molecule propylene glycol (PG) has robust virucidal activity. Propylene glycol rapidly inactivates a broad range of viruses including influenza A, SARS‐CoV‐2 and rotavirus and reduces disease burden in mice when administered intranasally at concentrations commonly found in nasal sprays. Most critically, vaporised PG efficiently abolishes influenza A virus and SARS‐CoV‐2 infectivity within airborne droplets, potently preventing infection at levels well below those tolerated by mammals. We present PG vapour as a first‐in‐class non‐toxic airborne virucide that can prevent transmission of existing and emergent viral pathogens, with clear and immediate implications for public health.

Suitable Disinfectants with Proven Efficacy for Genetically Modified Viruses and Viral Vectors.

Viral disinfection is important for medical facilities, the food industry, and the veterinary field, especially in terms of controlling virus outbreaks. Therefore, standardized methods and activity levels are available for these areas. Usually, disinfectants used in these areas are characterized by their activity against test organisms (i.e., viruses, bacteria, and/or yeasts). This activity is usually determined using a suspension test in which the test organism is incubated with the respective disinfectant in solution to assess its bactericidal, yeasticidal, or virucidal activity. In addition, carrier methods that more closely reflect real-world applications have been developed, in which microorganisms are applied to the surface of a carrier (e.g., stainless steel frosted glass, or polyvinyl chloride (PVC)) and then dried. However, to date, no standardized methods have become available for addressing genetically modified vectors or disinfection-resistant oncolytic viruses such as the H1-parvovirus. Particularly, such non-enveloped viruses, which are highly resistant to disinfectants, are not taken into account in European standards. This article proposes a new activity claim known as "virucidal activity PLUS", summarizes the available methods for evaluating the virucidal activity of chemical disinfectants against genetically modified organisms (GMOs) using current European standards, including the activity against highly resistant parvoviridae such as the adeno-associated virus (AAV), and provides guidance on the selection of disinfectants for pharmaceutical manufacturers, laboratories, and clinical users.

Remdesivir-Loaded Nanoliposomes Stabilized by Chitosan/Hyaluronic Acid Film with a Potential Application in the Treatment of Coronavirus Infection.

An object of the present study was the development of liposomes loaded with the medicine Veklury® (remdesivir) stabilized by electrostatic adsorption of polysaccharide film formed from chitosans with different physicochemical characteristics and hyaluronic acid. The functionalization of the structures was achieved through the inclusion of an aptamer (oligonucleotide sequence) with specific affinity to the spike protein of the human coronavirus HCoV-OC43. The hydrodynamic size, electrokinetic potential and stability of the structures were evaluated at each step in the procedure. The encapsulation efficiency and loaded amount of remdesivir (99% and 299 µg/mL) were estimated by UV-vis spectroscopy. Our investigations showed manifestation of promising tendencies for prolonged periods of the drug release and increased effectiveness of its antiviral action. Among all studied versions of the delivery system, the most distinguished and suitable in a model coronavirus therapy are the liposomes formed from chitosan oligosaccharides. The cytotoxicity of the liposomes was determined against the HCT-8 cell line. A cytopathic effect inhibition test was used for the assessment of the antiviral activity of the compounds. The virucidal activity and the effect on the viral adsorption of the samples were reported by the end-point dilution method, and the alteration in viral titer was determined as Δlgs compared to untreated controls. The redox-modulating properties of the nanoparticles were studied in vitro in certain/several/a few chemical model systems. Our investigations showed a manifestation of promising tendencies for a prolonged effect of the drug release and increased effectiveness of its antiviral action.