Polymers in the Medical Antiviral Front-Line

Synthesis and characterization of antimicrobial colloidal polyanilines

The potential application of colloidal polyaniline (PANI) as an antimicrobial is limited by challenges related to solubility in common organic solvents, scalability, and antimicrobial potency. To address these limitations, we introduced a functionalized PANI (fPANI) with carboxyl groups through the polymerisation of aniline and 3-aminobenzoic acid in a 1:1 molar ratio. fPANI is more soluble than PANI which was determined using a qualitative study. We further enhanced the solubility and antimicrobial activity of fPANI by incorporating Ag nanoparticles onto the synthesized fPANI colloid via direct addition of 10 mM AgNO3. The improved solubility can be attributed to an approximately 3-fold reduction in size of particles. Mean particle sizes are measured at 1322 nm for fPANI colloid and 473 nm for fPANI-Ag colloid, showing a high dispersion and deagglomeration effect from Ag nanoparticles. Antimicrobial tests demonstrated that fPANI-Ag colloids exhibited superior potency against Gram-positive Staphylococcus aureus, Gram-negative Escherichia coli, and Bacteriophage PhiX 174 when compared to fPANI alone. The minimum bactericidal concentration (MBC) and minimum virucidal concentration (MVC) values were halved for fPANI-Ag compared to fPANI colloid and attributed to the combination of Ag nanoparticles with the fPANI polymer. The antimicrobial fPANI-Ag colloid presented in this study shows promising results, and further exploration into scale-up can be pursued for potential biomedical applications.

Production and characterization of polyhydroxybutyrate bioplastic precursor from Parageobacillus toebii using low-cost substrates and its potential antiviral activity

There is an increasing desire for bioplastics produced from renewable resources as an alternative to their petrochemical counterparts. These biopolymers have long-unnoticed antiviral properties. This study aimed to produce and characterize bioplastics by Parageobacillus toebii using low-cost substrates and determine their antiviral activity against coxsackievirus B4. Seven low-cost substrates (bagasse, water hyacinth, rice straw, rice water, sesame husks, molasses, and corn syrup) were compared with glucose for bioplastic precursor production. The highest bioplastic produced was from water hyacinth and glucose, followed by molasses, rice straw, rice water, sesame husks, and bagasse. Water hyacinth and glucose media were further optimized to increase the bioplastic precursor yield. The optimization of the media leads to increases in bioplastic precursor yields of 1.8-fold (3.456 g/L) and 1.496-fold (2.768 g/L), respectively. These bioplastics were further characterized by thermogravimetric analysis (TGA), Fourier-transformed infrared (FTIR) spectroscopy, proton nuclear magnetic resonance (1H NMR), and gas chromatography-mass spectrometry (GC-MS). They are thermostable, and their characterizations confirm the presence of polyhydroxybutyrate. The antiviral assay showed reasonable antiviral effects for bioplastics from water hyacinth (80.33 %) and glucose (55.47 %) media at 250 μg/mL maximum non-toxic concentrations (MNTC). The present investigation demonstrates a low-cost model for producing polyhydroxybutyrate bioplastic precursor for antiviral applications.

Nanofiberous facemasks as protectives against pandemic respiratory viruses

INTRODUCTION

Wearing protective face masks and respirators has been a necessity to reduce the transmission rate of respiratory viruses since the outbreak of the coronavirus (COVID-19) disease. Nevertheless, the outbreak has revealed the need to develop efficient air filter materials and innovative anti-microbial protectives. Nanofibrous facemasks, either loaded with antiviral nanoparticles or not, are very promising personal protective equipment (PPE) against pandemic respiratory viruses.

AREAS COVERED

In this review, multiple types of face masks and respirators are discussed as well as filtration mechanisms of particulates. In this regard, the limitations of traditional face masks were summarized and the advancement of nanotechnology in developing nanofibrous masks and air filters was discussed. Different methods of preparing nanofibers were explained. The various approaches used for enhancing nanofibrous face masks were covered.

EXPERT OPINION

Although wearing conventional face masks can limit viral infection spread to some extent, the world is in great need for more protective face masks. Nanofibers can block viral particles efficiently and can be incorporated into face masks in order to enhance their filtration efficiency. Also, we believe that other modifications such as addition of antiviral nanoparticles can significantly increase the protection power of facemasks.

Bacteriophage Challenges in Industrial Processes: A Historical Unveiling and Future Outlook

Humans have used fermentation processes since the Neolithic period, mainly to produce beverages. The turning point occurred in the 1850s, when Louis Pasteur discovered that fermentation resulted from the metabolism of living microorganisms. This discovery led to the fast development of fermented food production. The importance of industrial processes based on fermentation significantly increased. Many branches of industry rely on the metabolisms of bacteria, for example, the dairy industry (cheese, milk, yogurts), pharmaceutical processes (insulin, vaccines, antibiotics), or the production of chemicals (acetone, butanol, acetic acid). These are the mass production processes involving a large financial outlay. That is why it is essential to minimize threats to production. One major threat affecting bacteria-based processes is bacteriophage infections, causing substantial economic losses. The first reported phage infections appeared in the 1930s, and companies still struggle to fight against phages. This review shows the cases of phage infections in industry and the most common methods used to prevent phage infections.

An Overview of Diverse Strategies To Inactivate Enterobacteriaceae-Targeting Bacteriophages

Bacteriophages are viruses that infect bacteria and thus threaten industrial processes relying on the production executed by bacterial cells. Industries bear huge economic losses due to such recurring and resilient infections. Depending on the specificity of the process, there is a need for appropriate methods of bacteriophage inactivation, with an emphasis on being inexpensive and high efficiency. In this review, we summarize the reports on antiphagents, i.e., antibacteriophage agents on inactivation of bacteriophages. We focused on bacteriophages targeting the representatives of the Enterobacteriaceae family, as its representative, Escherichia coli, is most commonly used in the bio-industry. The review is divided into sections dealing with bacteriophage inactivation by physical factors, chemical factors, and nanotechnology-based solutions.

An Update on Current Antiviral Strategies to Combat Human Cytomegalovirus Infection

Human cytomegalovirus (HCMV) remains an essential global concern due to its distinct life cycle, mutations and latency. As HCMV is a herpesvirus, it establishes a lifelong persistence in the host through a chronic state of infection. Immunocompromised individuals are at risk of significant morbidity and mortality from the virus. Until now, no effective vaccine has been developed to combat HCMV infection. Only a few antivirals targeting the different stages of the virus lifecycle and viral enzymes are licensed to manage the infection. Therefore, there is an urgent need to find alternate strategies to combat the infection and manage drug resistance. This review will provide an insight into the clinical and preclinical antiviral approaches, including HCMV antiviral drugs and nucleic acid-based therapeutics.

Cerium Oxide Nanoparticles/Polyacrylonitrile Nanofibers as Impervious Barrier against Viral Infections

BACKGROUND

Using face masks is one of the protective measures to reduce the transmission rate of coronavirus. Its massive spread necessitates developing safe and effective antiviral masks (filters) applying nanotechnology.

METHODS

Novel electrospun composites were fabricated by incorporating cerium oxide nanoparticles (CeO2 NPs) into polyacrylonitrile (PAN) electrospun nanofibers that can be used in the future in face masks. The effects of the polymer concentration, applied voltage, and feeding rate during the electrospinning were studied. The electrospun nanofibers were characterized using SEM, XRD, FTIR, and tensile strength testing. The cytotoxic effect of the nanofibers was evaluated in the Vero cell line using the MTT colorimetric assay, and the antiviral activity of the proposed nanofibers was evaluated against the human adenovirus type 5 (ADV-5) respiratory virus.

RESULTS

The optimum formulation was fabricated with a PAN concentration of 8%, w/v loaded with 0.25%, w/v CeO2 NPs with a feeding rate of 26 KV and an applied voltage of 0.5 mL/h. They showed a particle size of 15.8 ± 1.91 nm and a zeta potential of -14 ± 0.141 mV. SEM imaging demonstrated the nanoscale features of the nanofibers even after incorporating CeO2 NPs. The cellular viability study showed the safety of the PAN nanofibers. Incorporating CeO2 NPs into these fibers further increased their cellular viability. Moreover, the assembled filter could prevent viral entry into the host cells as well as prevent their replication inside the cells via adsorption and virucidal antiviral mechanisms.

CONCLUSIONS

The developed cerium oxide nanoparticles/polyacrylonitrile nanofibers can be considered a promising antiviral filter that can be used to halt virus spread.

Antibacterial and Antiviral Effects of Ag, Cu and Zn Metals, Respective Nanoparticles and Filter Materials Thereof against Coronavirus SARS-CoV-2 and Influenza A Virus

Due to the high prevalence of infectious diseases and their concurrent outbreaks, there is a high interest in developing novel materials with antimicrobial properties. Antibacterial and antiviral properties of a range of metal-based nanoparticles (NPs) are a promising means to fight airborne diseases caused by viruses and bacteria. The aim of this study was to test antimicrobial metals and metal-based nanoparticles efficacy against three viruses, namely influenza A virus (H1N1; A/WSN/1933) and coronaviruses TGEV and SARS-CoV-2; and two bacteria, Escherichia coli and Staphylococcus aureus. The efficacy of ZnO, CuO, and Ag NPs and their respective metal salts, i.e., ZnSO₄, CuSO₄, and AgNO₃, was evaluated in suspensions, and the compounds with the highest antiviral efficacy were chosen for incorporation into fibers of cellulose acetate (CA), using electrospinning to produce filter materials for face masks. Among the tested compounds, CuSO₄ demonstrated the highest efficacy against influenza A virus and SARS-CoV-2 (1 h IC50 1.395 mg/L and 0.45 mg/L, respectively), followed by Zn salt and Ag salt. Therefore, Cu compounds were selected for incorporation into CA fibers to produce antiviral and antibacterial filter materials for face masks. CA fibers comprising CuSO₄ decreased SARS-CoV-2 titer by 0.38 logarithms and influenza A virus titer by 1.08 logarithms after 5 min of contact; after 1 h of contact, SARS-COV-2 virus was completely inactivated. Developed CuO- and CuSO₄-based filter materials also efficiently inactivated the bacteria Escherichia coli and Staphylococcus aureus. The metal NPs and respective metal salts were potent antibacterial and antiviral compounds that were successfully incorporated into the filter materials of face masks. New antibacterial and antiviral materials developed and characterized in this study are crucial in the context of the ongoing SARS-CoV-2 pandemic and beyond.

A review on disinfection methods for inactivation of waterborne viruses

Water contamination is a global health problem, and the need for safe water is ever-growing due to the public health implications of unsafe water. Contaminated water could contain pathogenic bacteria, protozoa, and viruses that are implicated in several debilitating human diseases. The prevalence and survival of waterborne viruses differ from bacteria and other waterborne microorganisms. In addition, viruses are responsible for more severe waterborne diseases such as gastroenteritis, myocarditis, and encephalitis among others, hence the need for dedicated attention to viral inactivation. Disinfection is vital to water treatment because it removes pathogens, including viruses. The commonly used methods and techniques of disinfection for viral inactivation in water comprise physical disinfection such as membrane filtration, ultraviolet (UV) irradiation, and conventional chemical processes such as chlorine, monochloramine, chlorine dioxide, and ozone among others. However, the production of disinfection by-products (DBPs) that accompanies chemical methods of disinfection is an issue of great concern due to the increase in the risks of harm to humans, for example, the development of cancer of the bladder and adverse reproductive outcomes. Therefore, this review examines the conventional disinfection approaches alongside emerging disinfection technologies, such as photocatalytic disinfection, cavitation, and electrochemical disinfection. Moreover, the merits, limitations, and log reduction values (LRVs) of the different disinfection methods discussed were compared concerning virus removal efficiency. Future research needs to merge single disinfection techniques into one to achieve improved viral disinfection, and the development of medicinal plant-based materials as disinfectants due to their antimicrobial and safety benefits to avoid toxicity is also highlighted.

Biodegradable Nonwoven Materials with Antipathogenic Layer

Biopolymer composites have received increasing attention for their beneficial properties such as being biodegradable and having less influence to the environment. Biodegradability of materials has become a desired feature due to the growing problems connected with waste management. The aim of the paper is to emphasize the importance of biodegradable textile materials, especially nonwoven materials with an anti-pathogenic layer. The article refers to the definitions of biodegradation, degradation and composting processes, as well as presenting methods of testing biodegradability depending on the type of material. The study gives examples of biodegradation of textiles and presents examples of qualitative and quantitative methods used for testing antimicrobial activity of biodegradable nonwovens with an anti-pathogenic layer.

Antiviral activity of chitosan nanoparticles encapsulating silymarin (Sil-CNPs) against SARS-CoV-2 (in silico and in vitro study)

To develop a specific treatment against COVID-19, we investigated silymarin–chitosan nanoparticles (Sil–CNPs) as an antiviral agent against SARS-CoV-2 using in silico and in vitro approaches. Docking of Sil and CNPs was carried out against SARS-CoV-2 spike protein using AutoDock Vina. CNPs and Sil–CNPs were prepared by the ionic gelation method and characterized by TEM, FT-IR, zeta analysis, and the membrane diffusion method to determine the drug release profile. Cytotoxicity was tested on both Vero and Vero E6 cell lines using the MTT assay. Minimum binding energies with spike protein and ACE2 were −6.6, and −8.0 kcal mol⁻¹ for CNPs, and −8.9, and −9.7 kcal mol⁻¹ for Sil, respectively, compared to −6.6 and −8.4 kcal mol⁻¹ respectively for remdesivir (RMV). CNPs and Sil–CNPs were prepared at sizes of 29 nm and 82 nm. The CC50 was 135, 35, and 110 μg mL⁻¹ for CNPs, Sil, and Sil–CNPs, respectively, on Vero E6. The IC50 was determined at concentrations of 0.9, 12 and 0.8 μg mL⁻¹ in virucidal/replication assays for CNPs, Sil, and Sil–CNPs respectively using crystal violet. These results indicate antiviral activity of Sil–CNPs against SARS-CoV-2.

To develop a specific treatment against COVID-19, we investigated silymarin–chitosan nanoparticles (Sil–CNPs) as an antiviral agent against SARS-CoV-2 using in silico and in vitro approaches.

Biomedical polymers: synthesis, properties, and applications

Biomedical polymers have been extensively developed for promising applications in a lot of biomedical fields, such as therapeutic medicine delivery, disease detection and diagnosis, biosensing, regenerative medicine, and disease treatment. In this review, we summarize the most recent advances in the synthesis and application of biomedical polymers, and discuss the comprehensive understanding of their property-function relationship for corresponding biomedical applications. In particular, a few burgeoning bioactive polymers, such as peptide/biomembrane/microorganism/cell-based biomedical polymers, are also introduced and highlighted as the emerging biomaterials for cancer precision therapy. Furthermore, the foreseeable challenges and outlook of the development of more efficient, healthier and safer biomedical polymers are discussed. We wish this systemic and comprehensive review on highlighting frontier progress of biomedical polymers could inspire and promote new breakthrough in fundamental research and clinical translation.

Design strategies for antiviral coatings and surfaces: A review☆

The routine disinfection and sanitization of surfaces, objects, and textiles has become a time-consuming but necessary task for managing the COVID-19 pandemic. Nonetheless, the excessive use of sanitizers and disinfectants promotes the development of antibiotic-resistant microbes. Moreover, that improper disinfection could lead to more virus transfer, which leads to more viral mutations. Recently developed antiviral surface coatings can reduce the reliance on traditional disinfectants. These surfaces remain actively antimicrobial between periods of active cleaning of the surfaces, allowing a much more limited and optimized use of disinfectants. The novel nature of these surfaces has led, however, to many inconsistencies within the rapidly growing literature. Here we provide tools to guide the design and development of antimicrobial and antiviral surfaces and coatings. We describe how engineers can best choose testing options and propose new avenues for antiviral testing. After defining testing protocols, we summarize potential inorganic and organic materials able to serve as antiviral surfaces and present their antiviral mechanisms. We discuss the main limitations to their application, including issues related to toxicity, antimicrobial resistance, and environmental concerns. We propose solutions to counter these limitations and highlight how the context of specific use of an antiviral surface must guide material selection. Finally, we discuss how the use of coatings that combine multiple antimicrobial mechanisms can avoid the development of antibiotic resistance and improve the antiviral properties of these surfaces.

Biodegradable Nanohybrid Materials as Candidates for Self-Sanitizing Filters Aimed at Protection from SARS-CoV-2 in Public Areas

The COVID-19 pandemic has raised the problem of efficient, low-cost materials enabling the effective protection of people from viruses transmitted through the air or via surfaces. Nanofibers can be a great candidate for efficient air filtration due to their structure, although they cannot protect from viruses. In this work, we prepared a wide range of nanofibrous biodegradable samples containing Ag (up to 0.6 at.%) and Cu (up to 20.4 at.%) exhibiting various wettability. By adjusting the magnetron current (0.3 A) and implanter voltage (5 kV), the deposition of TiO₂ and Ag⁺ implantation into PCL/PEO nanofibers was optimized in order to achieve implantation of Ag⁺ without damaging the nanofibrous structure of the PCL/PEO. The optimal conditions to implant silver were achieved for the PCL-Ti0.3-Ag-5kV sample. The coating of PCL nanofibers by a Cu layer was successfully realized by magnetron sputtering. The antiviral activity evaluated by widely used methodology involving the cultivation of VeroE6 cells was the highest for PCL-Cu and PCL-COOH, where the VeroE6 viability was 73.1 and 68.1%, respectively, which is significantly higher compared to SARS-CoV-2 samples without self-sanitizing (42.8%). Interestingly, the samples with implanted silver and TiO₂ exhibited no antiviral effect. This difference between Cu and Ag containing nanofibers might be related to the different concentrations of ions released from the samples: 80 μg/L/day for Cu²⁺ versus 15 µg/L/day for Ag⁺. The high antiviral activity of PCL-Cu opens up an exciting opportunity to prepare low-cost self-sanitizing surfaces for anti-SARS-CoV-2 protection and can be essential for air filtration application and facemasks. The rough cost estimation for the production of a biodegradable nanohybrid PCL-Cu facemask revealed ~$0.28/piece, and the business case for the production of these facemasks would be highly positive, with an Internal Rate of Return of 34%.

Efficacy of sodium polyanethol sulfonate on herpes simplex virus-1 infection in vitro

Objective: To investigate the effect of sodium polyanethol sulfonate (SPS) on herpes simplex virus type 1 (HSV-1) infection in vitro.

Methods

Human corneal epithelial (HCE-T) cells and Vero cells were infected with HSV-1 [HSV-1 f strain, HSV-1f; HSV-1-H129 with green fluorescent protein (GFP) knock-in, HSV-1g]. SPS was added to the culture medium at various concentrations in time-of-addition assay. Experiments including photography of fluorescence in HSV-1g or plaque formation by HSV-1f, western blot assays, real-time RT-PCR assays, cytopathic effect inhibition assays, cytotoxicity assays, and viral absorption and penetration assays were performed to explore the antiviral effect and mechanism of the compounds.

Results

We identified that SPS reduced the replication of HSV-1 in HCE-T and Vero cells in a dose-dependent manner. HSV-1g fluorescence was reduced by 66.3% and 65.4% in HCE-T and Vero cells, respectively, after treatment with 0.4 µg/ml SPS. Furthermore, the viral fluorescence intensities were inhibited by SPS in a dose-dependent manner when the viruses or cells were preincubated with SPS. Relative levels of the ICP4 protein and VP16 mRNA were decreased by SPS in a dose-dependent manner. Moreover, the IC₅₀ values of SPS for HSV-1g and HSV-1f in HCE-T cells were 0.69±0.09 μg/ml and 1.63±0.44 μg/ml, respectively. Even 10,000 µg/ml SPS had no obvious cytotoxicity toward HCE-T and Vero cells. Importantly, viral absorption and penetration assays showed that the relative fluorescence intensity of HSV-1g was significantly reduced by SPS in a dose-dependent manner in the absorption test, but no change was observed in the penetration test.

Conclusions

SPS inhibits HSV-1 replication in HCE-T and Vero cells, indicating that SPS has the potential for treating HSV-1 infection, particularly HSV-1 keratitis.

Inhibition of SARS-CoV-2 spike protein entry using biologically modified polyacrylonitrile nanofibers: in vitro study towards specific antiviral masks

With the increase in the contagiousness rates of Coronavirus disease (COVID-19), new strategies are needed to protect people and to halt the from the spread of viruses.

Food packaging wastes amid the COVID-19 pandemic: Trends and challenges

BACKGROUND

The COVID-19 crisis generated changes in consumer behavior related to food purchase and the management of food packaging. Due to the intensification of online purchases for home delivery, there has been an increase in the use of food packaging (mostly non-biodegradable or non-renewable). Moreover, the fear of contamination with SARS-CoV-2 through contact with materials and surfaces has led to an intensified disposal of food packaging, promoting a setback in waste management.

SCOPE AND APPROACH

The purpose of this short commentary is to address the impacts of increased use and disposal of food packaging during the COVID-19 pandemic. Technological solutions have been presented as tools to minimize the environmental impacts of the increased volume of disposed food packaging (namely, the development of biodegradable food packaging) as well as to minimize the occurrence of cross-contamination (namely, the incorporation of active antiviral components).

KEY FINDINGS AND CONCLUSIONS

The consumer behavior in the COVID-19 pandemic requires actions concerning adoption of bioplastics for single-use food packaging. Polylactide (PLA) stands out for high production viability, performance comparable to those of petroleum-based thermoplastics, and carbon neutral life cycle. Moreover, active components including organic compounds (resveratrol, luteolin, myricetin etc.) and metals (e.g., copper, zinc, silver) can mitigate cross-contamination. Therefore, there are opportunities to reduce food packaging-related environmental footprints while also decreasing the occurrence of surface-mediated cross-contamination.

A review of the antiviral activity of Chitosan, including patented applications and its potential use against COVID-19

Chitosan is an abundant organic polysaccharide, which can be relatively easily obtained by chemical modification of animal or fungal source materials. Chitosan and its derivatives have been shown to exhibit direct antiviral activity, to be useful vaccine adjuvants and to have potential anti-SARS-CoV-2 activity. This thorough and timely review looks at the recent history of investigations into the role of chitosan and its derivatives as an antiviral agent and proposes a future application in the treatment of endemic SARS-CoV-2.

Rapid and Repetitive Inactivation of SARS-CoV-2 and Human Coronavirus on Self-Disinfecting Anionic Polymers

While the ongoing COVID-19 pandemic affirms an urgent global need for effective vaccines as second and third infection waves are spreading worldwide and generating new mutant virus strains, it has also revealed the importance of mitigating the transmission of SARS-CoV-2 through the introduction of restrictive social practices. Here, it is demonstrated that an architecturally- and chemically-diverse family of nanostructured anionic polymers yield a rapid and continuous disinfecting alternative to inactivate coronaviruses and prevent their transmission from contact with contaminated surfaces. Operating on a dramatic pH-drop mechanism along the polymer/pathogen interface, polymers of this archetype inactivate the SARS-CoV-2 virus, as well as a human coronavirus surrogate (HCoV-229E), to the minimum detection limit within minutes. Application of these anionic polymers to frequently touched surfaces in medical, educational, and public-transportation facilities, or personal protection equipment, can provide rapid and repetitive protection without detrimental health or environmental complications.

Inhibition of Herpes Simplex Virus Type 1 Attachment and Infection by Sulfated Polyglycerols with Different Architectures

Inhibition of herpes simplex virus type 1 (HSV-1) binding to the host cell surface by highly sulfated architectures is among the promising strategies to prevent virus entry and infection. However, the structural flexibility of multivalent inhibitors plays a major role in effective blockage and inhibition of virus receptors. In this study, we demonstrate the inhibitory effect of a polymer scaffold on the HSV-1 infection by using highly sulfated polyglycerols with different architectures (linear, dendronized, and hyperbranched). IC₅₀ values for all synthesized sulfated polyglycerols and the natural sulfated polymer heparin were determined using plaque reduction infection assays. Interestingly, an increase in the IC₅₀ value from 0.03 to 374 nM from highly flexible linear polyglycerol sulfate (LPGS) to less flexible scaffolds, namely, dendronized polyglycerol sulfate and hyperbranched polyglycerol sulfate was observed. The most potent LPGS inhibits HSV-1 infection 295 times more efficiently than heparin, and we show that LPGS has a much reduced anticoagulant capacity when compared to heparin as evidenced by measuring the activated partial thromboplastin time. Furthermore, prevention of infection by LPGS and the commercially available drug acyclovir were compared. All tested sulfated polymers do not show any cytotoxicity at concentrations of up to 1 mg/mL in different cell lines. We conclude from our results that more flexible polyglycerol sulfates are superior to less flexible sulfated polymers with respect to inhibition of HSV-1 infection and may constitute an alternative to the current antiviral treatments of this ubiquitous pathogen.