Dual-Action Effect of Gallium and Silver Providing Osseointegration and Antibacterial Properties to Calcium Titanate Coatings on Porous Titanium Implants.

Previously, functional coatings on 3D-printed titanium implants were developed to improve their biointegration by separately incorporating Ga and Ag on the biomaterial surface. Now, a thermochemical treatment modification is proposed to study the effect of their simultaneous incorporation. Different concentrations of AgNO3 and Ga(NO3)3 are evaluated, and the obtained surfaces are completely characterized. Ion release, cytotoxicity, and bioactivity studies complement the characterization. The provided antibacterial effect of the surfaces is analyzed, and cell response is assessed by the study of SaOS-2 cell adhesion, proliferation, and differentiation. The Ti surface doping is confirmed by the formation of Ga-containing Ca titanates and nanoparticles of metallic Ag within the titanate coating. The surfaces generated with all combinations of AgNO3 and Ga(NO3)3 concentrations show bioactivity. The bacterial assay confirms a strong bactericidal impact achieved by the effect of both Ga and Ag present on the surface, especially for Pseudomonas aeruginosa, one of the main pathogens involved in orthopedic implant failures. SaOS-2 cells adhere and proliferate on the Ga/Ag-doped Ti surfaces, and the presence of gallium favors cell differentiation. The dual effect of both metallic agents doping the titanium surface provides bioactivity while protecting the biomaterial from the most frequent pathogens in implantology.

Virucidal efficacy of a novel silver-based disinfectant against SARS-CoV-2 Omicron BA.5.

In this study we evaluated the antiviral activity of the Silver Barrier® disinfectant against SARSCoV-2. Silver Barrier® showed time- and concentration-dependent antiviral activity against SARSCoV-2. After 5 min contact time, Silver Barrier® at 0.002% showed a strong inhibitory effect (p<0.001), with a 2-fold reduction of viral genome copy numbers, and a robust suppression (94%) of SARS-CoV-2 infectivity. Considering the effects obtained in solution and within a very short time, Silver Barrier® stands as an excellent new candidate for the disinfection of work environments, especially at the healthcare level, where there are people at high risk of serious illnesses.

Antimicrobial Performance of Innovative Functionalized Surfaces Based on Enamel Coatings: The Effect of Silver-Based Additives on the Antibacterial and Antifungal Activity.

Frequently touched surfaces (FTS) that are contaminated with pathogens are one of the main sources of nosocomial infections, which commonly include hospital-acquired and healthcare-associated infections (HAIs). HAIs are considered the most common adverse event that has a significant burden on the public's health worldwide currently. The persistence of pathogens on contaminated surfaces and the transmission of multi-drug resistant (MDR) pathogens by way of healthcare surfaces, which are frequently touched by healthcare workers, visitors, and patients increase the risk of acquiring infectious agents in hospital environments. Moreover, not only in hospitals but also in high-traffic public places, FTS play a major role in the spreading of pathogens. Consequently, attention has been devoted to developing novel and alternative methods to tackle this problem. This study planned to produce and characterize innovative functionalized enameled coated surfaces supplemented with 1% AgNO3 and 2% AgNO3. Thus, the antimicrobial properties of the enamels against relevant nosocomial pathogens including the Gram-positive Staphylococcus aureus and the Gram-negative Escherichia coli and the yeast Candida albicans were assessed using the ISO:22196:2011 norm.

Biogenic nanosilver-fabricated endotracheal tube to prevent microbial colonization in a veterinary hospital.

COVID-19 patients have often required prolonged endotracheal intubation, increasing the risk of developing ventilator-associated pneumonia (VAP). A preventive strategy is proposed based on an endotracheal tube (ETT) modified by the in situ deposition of eucalyptus-mediated synthesized silver nanoparticles (AgNPs). The surfaces of the modified ETT were embedded with AgNPs of approximately 28 nm and presented a nanoscale roughness. Energy dispersive X-ray spectroscopy confirmed the presence of silver on and inside the coated ETT, which exhibited excellent antimicrobial activity against Gram-positive and Gram-negative bacteria, and fungi, including multidrug-resistant clinical isolates. Inhibition of planktonic growth and microbial adhesion ranged from 99 to 99.999% without cytotoxic effects on mammalian cells. Kinetic studies showed that microbial adhesion to the coated surface was inhibited within 2 h. Cell viability in biofilms supplemented with human tracheal mucus was reduced by up to 95%. In a porcine VAP model, the AgNPs-coated ETT prevented adhesion of Pseudomonas aeruginosa and completely inhibited bacterial invasion of lung tissue. The potential antimicrobial efficacy and safety of the coated ETT were established in a randomized control trial involving 47 veterinary patients. The microbial burden was significantly lower on the surface of the AgNPs-coated ETT than on the uncoated ETT (p < 0.05). KEY POINTS: • Endotracheal tube surfaces were modified by coating with green-synthesized AgNPs • P. aeruginosa burden of endotracheal tube and lung was reduced in a porcine model • Effective antimicrobial activity and safety was demonstrated in a clinical trial.

Fabrication of silver nanoparticles-deposited fabrics as a potential candidate for the development of reusable facemasks and evaluation of their performance.

Recently, wearing facemasks in public has been raised due to the coronavirus disease 2019 epidemic worldwide. However, the performance and effectiveness of many existing products have raised significant concerns among people and professionals. Therefore, greater attempts have been focused recently to increase the efficacy of these products scientifically and industrially. In this respect, doping or impregnating facemask fabrics with metallic substances or nanoparticles like silver nanoparticles has been proposed. So, in the present study, we aimed to sonochemically coat silver nanoparticles on the non-woven Spunbond substrates at different sonication times and concentrations to develop antibacterial and antiviral facemask. The coated substrates were characterized using Field Emission Scanning Electron Microscope, Energy Dispersive X-Ray, X-ray diffraction, and Thermogravimetry analysis. The amount of silver released from the coated substrates was measured by atomic absorption spectroscopy. The filtration efficiency, pressure drop, and electrical conductivity of the coated samples were also investigated. The antibacterial activity of fabrics was evaluated against Escherichia coli and Staphylococcus aureus. Cellular viability of samples assessed by MTT and brine shrimp lethality tests. The results revealed that the higher sonication times and precursor concentrations result in a higher and more stable coating, larger particle size, wider particle size distribution, and lower content of released silver. Coated fabrics also revealed enhanced filtration efficiency (against nanosize particles), desired pressure drop, and antibacterial activity without significant cytotoxicity toward HEK 293 cells and Artemia nauplii. As a result, the coated fabrics could find potential applications in the development of facemasks for protection against different pathogenic entities.

Highin vitroactivity of gold and silver nanoparticles from Solanum mammosum L. against SARS-CoV-2 surrogate Phi6 and viral model PhiX174.

The search for new strategies to curb the spread of the SARS-CoV-2 coronavirus, which causes COVID-19, has become a global priority. Various nanomaterials have been proposed as ideal candidates to inactivate the virus; however, because of the high level of biosecurity required for their use, alternative models should be determined. This study aimed to compare the effects of two types of nanomaterials gold (AuNPs) and silver nanoparticles (AgNPs), recognized for their antiviral activity and affinity with the coronavirus spike protein using PhiX174 and enveloped Phi6 bacteriophages as models. To reduce the toxicity of nanoparticles, a species known for its intermediate antiviral activity,Solanum mammosumL. (Sm), was used. NPs prepared with sodium borohydride (NaBH4) functioned as the control. Antiviral activity against PhiX174 and Phi6 was analyzed using its seed, fruit, leaves, and essential oil; the leaves were the most effective on Phi6. Using the aqueous extract of the leaves, AuNPs-Sm of 5.34 ± 2.25 nm and AgNPs-Sm of 15.92 ± 8.03 nm, measured by transmission electron microscopy, were obtained. When comparing NPs with precursors, both gold(III) acetate and silver nitrate were more toxic than their respective NPs (99.99% at 1 mg ml-1). The AuNPs-Sm were less toxic, reaching 99.30% viral inactivation at 1 mg ml-1, unlike the AgNPs-Sm, which reached 99.94% at 0.01 mg ml-1. In addition, cell toxicity was tested in human adenocarcinoma alveolar basal epithelial cells (A549) and human foreskin fibroblasts. Gallic acid was the main component identified in the leaf extract using high performance liquid chromatography with diode array detection (HPLC-DAD). The FT-IR spectra showed the presence of a large proportion of polyphenolic compounds, and the antioxidant analysis confirmed the antiradical activity. The control NPs showed less antiviral activity than the AuNPs-Sm and AgNPs-Sm, which was statistically significant; this demonstrates that both theS. mammosumextract and its corresponding NPs have a greater antiviral effect on the surrogate Phi bacteriophage, which is an appropriate model for studying SARS-CoV-2.

Antiviral efficacy of cerium oxide nanoparticles.

Nanomaterials are prospective candidates for the elimination of viruses due to their multimodal mechanisms of action. Here, we tested the antiviral potential of a largely unexplored nanoparticle of cerium dioxide (CeO2). Two nano-CeO2 with opposing surface charge, (+) and (-), were assessed for their capability to decrease the plaque forming units (PFU) of four enveloped and two non-enveloped viruses during 1-h exposure. Statistically significant antiviral activity towards enveloped coronavirus SARS-CoV-2 and influenza virus was registered already at 20 mg Ce/l. For other two enveloped viruses, transmissible gastroenteritis virus and bacteriophage φ6, antiviral activity was evidenced at 200 mg Ce/l. As expected, the sensitivity of non-enveloped viruses towards nano-CeO2 was significantly lower. EMCV picornavirus showed no decrease in PFU until the highest tested concentration, 2000 mg Ce/l and MS2 bacteriophage showed slight non-monotonic response to high concentrations of nano-CeO2(-). Parallel testing of antiviral activity of Ce3+ ions and SiO2 nanoparticles allows to conclude that nano-CeO2 activity was neither due to released Ce-ions nor nonspecific effects of nanoparticulates. Moreover, we evidenced higher antiviral efficacy of nano-CeO2 compared with Ag nanoparticles. This result along with low antibacterial activity and non-existent cytotoxicity of nano-CeO2 allow us to propose CeO2 nanoparticles for specific antiviral applications.

Antifungal Effect of Nanoparticles against COVID-19 Linked Black Fungus: A Perspective on Biomedical Applications.

Severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is a highly transmissible and pathogenic coronavirus that has caused a 'coronavirus disease 2019' (COVID-19) pandemic in multiple waves, which threatens human health and public safety. During this pandemic, some patients with COVID-19 acquired secondary infections, such as mucormycosis, also known as black fungus disease. Mucormycosis is a serious, acute, and deadly fungal infection caused by Mucorales-related fungal species, and it spreads rapidly. Hence, prompt diagnosis and treatment are necessary to avoid high mortality and morbidity rates. Major risk factors for this disease include uncontrolled diabetes mellitus and immunosuppression that can also facilitate increases in mucormycosis infections. The extensive use of steroids to prevent the worsening of COVID-19 can lead to black fungus infection. Generally, antifungal agents dedicated to medical applications must be biocompatible, non-toxic, easily soluble, efficient, and hypoallergenic. They should also provide long-term protection against fungal growth. COVID-19-related black fungus infection causes a severe increase in fatalities. Therefore, there is a strong need for the development of novel and efficient antimicrobial agents. Recently, nanoparticle-containing products available in the market have been used as antimicrobial agents to prevent bacterial growth, but little is known about their efficacy with respect to preventing fungal growth, especially black fungus. The present review focuses on the effect of various types of metal nanoparticles, specifically those containing silver, zinc oxide, gold, copper, titanium, magnetic, iron, and carbon, on the growth of various types of fungi. We particularly focused on how these nanoparticles can impact the growth of black fungus. We also discussed black fungus co-infection in the context of the global COVID-19 outbreak, and management and guidelines to help control COVID-19-associated black fungus infection. Finally, this review aimed to elucidate the relationship between COVID-19 and mucormycosis.

A novel antibacterial and antifouling nanocomposite coated endotracheal tube to prevent ventilator-associated pneumonia.

BACKGROUND: The endotracheal tube (ETT) is an essential medical device to secure the airway patency in patients undergoing mechanical ventilation or general anesthesia. However, long-term intubation eventually leads to complete occlusion, ETTs potentiate biofilm-related infections, such as ventilator-associated pneumonia. ETTs are mainly composed of medical polyvinyl chloride (PVC), which adheres to microorganisms to form biofilms. Thus, a simple and efficient method was developed to fabricate CS-AgNPs@PAAm-Gelatin nanocomposite coating to achieve dual antibacterial and antifouling effects. RESULTS: The PAAm-Gelatin (PAAm = polyacrylamide) molecular chain gel has an interpenetrating network with a good hydrophilicity and formed strong covalent bonds with PVC-ETTs, wherein silver nanoparticles were used as antibacterial agents. The CS-AgNPs@PAAm-Gelatin coating showed great resistance and antibacterial effects against Staphylococcus aureus and Pseudomonas aeruginosa. Its antifouling ability was tested using cell, protein, and platelet adhesion assays. Additionally, both properties were comprehensively evaluated using an artificial broncho-lung model in vitro and a porcine mechanical ventilation model in vivo. These remarkable results were further confirmed that the CS-AgNPs@PAAm-Gelatin coating exhibited an excellent antibacterial capacity, an excellent stain resistance, and a good biocompatibility. CONCLUSIONS: The CS-AgNPs@PAAm-Gelatin nanocomposite coating effectively prevents the occlusion and biofilm-related infection of PVC-ETTs by enhancing the antibacterial and antifouling properties, and so has great potential for future clinical applications.

Reactive silver inks for antiviral, repellent medical textiles with ultrasonic bleach washing durability compared to silver nanoparticles.

Medical textiles are subject to particularly harsh disinfection procedures in healthcare settings where exposure risks are high. This work demonstrates a fabric treatment consisting of a reactive silver ink and low surface energy PDMS polymer that provides for superhydrophobicity and antiviral properties against enveloped herpes simplex virus stocks even after extended ultrasonic bleach washing. The antiviral properties of reactive silver ink has not been previously reported or compared with silver nanoparticles. The fabric treatment exhibits high static contact angles and low contact angle hysteresis with water, even after 300 minutes of ultrasonic bleach washing. Similarly, after this bleach washing treatment, the fabric treatment shows reductions of infectious virus quantities by about 2 logs compared to controls for enveloped viruses. The use of silver ink provides for better antiviral efficacy and durability compared to silver nanoparticles due to the use of reactive ionic silver, which demonstrates more conformal coverage of fabric microfibers and better adhesion. This study provides insights for improving the wash durability of antiviral silver fabric treatments and demonstrates a bleach wash durable, repellent antiviral treatment for reusable, functional personal protective equipment applications.

Ångstrom-scale silver particles potently combat SARS-CoV-2 infection by suppressing the ACE2 expression and inflammatory responses.

The SARS-CoV-2 pandemic has become a severe global public health event, and the development of protective and therapeutic strategies is urgently needed. Downregulation of angiotensin converting enzyme 2 (ACE2; one of the important SARS-CoV-2 entry receptors) and aberrant inflammatory responses (cytokine storm) are the main targets to inhibit and control COVID-19 invasion. Silver nanomaterials have well-known pharmaceutical properties, including antiviral, antibacterial, and anticancer properties. Here, based on a self-established metal evaporation-condensation-size graded collection system, smaller silver particles reaching the Ångstrom scale (AgÅPs) were fabricated and coated with fructose to obtain a stabilized AgÅP solution (F-AgÅPs). F-AgÅPs potently inactivated SARS-CoV-2 and prevented viral infection. Considering the application of anti-SARS-CoV-2, a sterilized F-AgÅP solution was produced via spray formulation. In our model, the F-AgÅP spray downregulated ACE2 expression and attenuated proinflammatory factors. Moreover, F-AgÅPs were found to be rapidly eliminated to avoid respiratory and systemic toxicity in this study as well as our previous studies. This work presents a safe and potent anti-SARS-CoV-2 agent using an F-AgÅP spray.

Microbial silver resistance mechanisms: recent developments.

In this mini-review, after a brief introduction into the widespread antimicrobial use of silver ions and nanoparticles against bacteria, fungi and viruses, the toxicity of silver compounds and the molecular mechanisms of microbial silver resistance are discussed, including recent studies on bacteria and fungi. The similarities and differences between silver ions and silver nanoparticles as antimicrobial agents are also mentioned. Regarding bacterial ionic silver resistance, the roles of the sil operon, silver cation efflux proteins, and copper-silver efflux systems are explained. The importance of bacterially produced exopolysaccharides as a physiological (biofilm) defense mechanism against silver nanoparticles is also emphasized. Regarding fungal silver resistance, the roles of metallothioneins, copper-transporting P-type ATPases and cell wall are discussed. Recent evolutionary engineering (adaptive laboratory evolution) studies are also discussed which revealed that silver resistance can evolve rapidly in bacteria and fungi. The cross-resistance observed between silver resistance and resistance to other heavy metals and antibiotics in bacteria and fungi is also explained as a clinically and environmentally important issue. The use of silver against bacterial and fungal biofilm formation is also discussed. Finally, the antiviral effects of silver and the use of silver nanoparticles against SARS-CoV-2 and other viruses are mentioned. To conclude, silver compounds are becoming increasingly important as antimicrobial agents, and their widespread use necessitates detailed understanding of microbial silver response and resistance mechanisms, as well as the ecological effects of silver compounds. Figure created with BioRender.com.

Nanoscale copper and silver thin film systems display differences in antiviral and antibacterial properties.

The current Coronavirus Disease 19 (COVID-19) pandemic has exemplified the need for simple and efficient prevention strategies that can be rapidly implemented to mitigate infection risks. Various surfaces have a long history of antimicrobial properties and are well described for the prevention of bacterial infections. However, their effect on many viruses has not been studied in depth. In the context of COVID-19, several surfaces, including copper (Cu) and silver (Ag) coatings have been described as efficient antiviral measures that can easily be implemented to slow viral transmission. In this study, we detected antiviral properties against Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) on surfaces, which were coated with Cu by magnetron sputtering as thin Cu films or as Cu/Ag ultrathin bimetallic nanopatches. However, no effect of Ag on viral titers was observed, in clear contrast to its well-known antibacterial properties. Further enhancement of Ag ion release kinetics based on an electrochemical sacrificial anode mechanism did not increase antiviral activity. These results clearly demonstrate that Cu and Ag thin film systems display significant differences in antiviral and antibacterial properties which need to be considered upon implementation.

Targeting of Silver Cations, Silver-Cystine Complexes, Ag Nanoclusters, and Nanoparticles towards SARS-CoV-2 RNA and Recombinant Virion Proteins.

Background: Nanosilver possesses antiviral, antibacterial, anti-inflammatory, anti-angiogenesis, antiplatelet, and anticancer properties. The development of disinfectants, inactivated vaccines, and combined etiotropic and immunomodulation therapy against respiratory viral infections, including COVID-19, remains urgent. Aim: Our goal was to determine the SARS-CoV-2 molecular targets (genomic RNA and the structural virion proteins S and N) for silver-containing nanomaterials. Methods: SARS-CoV-2 gene cloning, purification of S2 and N recombinant proteins, viral RNA isolation from patients' blood samples, reverse transcription with quantitative real-time PCR ((RT)2-PCR), ELISA, and multiplex immunofluorescent analysis with magnetic beads (xMAP) for detection of 17 inflammation markers. Results: Fluorescent Ag nanoclusters (NCs) less than 2 nm with a few recovered silver atoms, citrate coated Ag nanoparticles (NPs) with diameters of 20-120 nm, and nanoconjugates of 50-150 nm consisting of Ag NPs with different protein envelopes were constructed from AgNO3 and analyzed by means of transmission electron microscopy (TEM), atomic force microscopy (AFM), ultraviolet-visible light absorption, and fluorescent spectroscopy. SARS-CoV-2 RNA isolated from COVID-19 patients' blood samples was completely cleaved with the artificial RNase complex compound Li+[Ag+2Cys2-(OH-)2(NH3)2] (Ag-2S), whereas other Ag-containing materials provided partial RNA degradation only. Treatment of the SARS-CoV-2 S2 and N recombinant antigens with AgNO3 and Ag NPs inhibited their binding with specific polyclonal antibodies, as shown by ELISA. Fluorescent Ag NCs with albumin or immunoglobulins, Ag-2S complex, and nanoconjugates of Ag NPs with protein shells had no effect on the interaction between coronavirus recombinant antigens and antibodies. Reduced production of a majority of the 17 inflammation biomarkers after treatment of three human cell lines with nanosilver was demonstrated by xMAP. Conclusion: The antiviral properties of the silver nanomaterials against SARS-CoV-2 coronavirus differed. The small-molecular-weight artificial RNase Ag-2S provided exhaustive RNA destruction but could not bind with the SARS-CoV-2 recombinant antigens. On the contrary, Ag+ ions and Ag NPs interacted with the SARS-CoV-2 recombinant antigens N and S but were less efficient at performing viral RNA cleavage. One should note that SARS-CoV-2 RNA was more stable than MS2 phage RNA. The isolated RNA of both the MS2 phage and SARS-CoV-2 were more degradable than the MS2 phage and coronavirus particles in patients' blood, due to the protection with structural proteins. To reduce the risk of the virus resistance, a combined treatment with Ag-2S and Ag NPs could be used. To prevent cytokine storm during the early stages of respiratory infections with RNA-containing viruses, nanoconjugates of Ag NPs with surface proteins could be recommended.

Phi 6 Bacteriophage Inactivation by Metal Salts, Metal Powders, and Metal Surfaces.

The interaction of phages with abiotic environmental surfaces is usually an understudied field of phage ecology. In this study, we investigated the virucidal potential of different metal salts, metal and ceramic powders doped with Ag and Cu ions, and newly fabricated ceramic and metal surfaces against Phi6 bacteriophage. The new materials were fabricated by spark plasma sintering (SPS) and/or selective laser melting (SLM) techniques and had different surface free energies and infiltration features. We show that inactivation of Phi6 in solutions with Ag and Cu ions can be as effective as inactivation by pH, temperature, or UV. Adding powder to Ag and Cu ion solutions decreased their virucidal effect. The newly fabricated ceramic and metal surfaces showed very good virucidal activity. In particular, 45%TiO2 + 5%Ag + 45%ZrO2 + 5%Cu, in addition to virus adhesion, showed virucidal and infiltration properties. The results indicate that more than 99.99% of viruses deposited on the new ceramic surface were inactivated or irreversibly attached to it.

Preparation, Characterization and Antimicrobial Properties of Nanosized Silver-Containing Carbon/Silica Composites from Rice Husk Waste.

Rice husk, one of the main side products in the rice production, and its sustainable management represent a challenge in many countries. Herein, we describe the use of this abundant agricultural bio-waste as feedstock for the preparation of silver-containing carbon/silica nano composites with antimicrobial properties. The synthesis was performed using a fast and cheap methodology consisting of wet impregnation followed by pyrolysis, yielding C/SiO2 composite materials doped with varying amounts of silver from 28 to 0.001 wt %. The materials were fully characterized and their antimicrobial activity against ESKAPE pathogens, namely E. faecium, S. aureus, K. pneumoniae, A. baumannii, P. aeruginosa, and E. coli, and the pathogenic yeast C. albicans was investigated. Sensitivities of these strains against the prepared materials were demonstrated, even with exceptional low amounts of 0.015 m% silver. Hence, we report a straightforward method for the synthesis of antimicrobial agents from abundant sources which addresses urgent questions like bio-waste valorization and affordable alternatives to increasingly fewer effective antibiotics.

Biocide effect against SARS-CoV-2 and ESKAPE pathogens of a noncytotoxic silver-copper nanofilm.

Nanometric materials with biocidal properties effective against severe acute respiratory syndrome-coronavirus-2 (SARS-CoV-2) and pathogenic bacteria could be used to modify surfaces, reducing the risk of touching transmission. In this work, we showed that a nanometric layer of bimetallic AgCu can be effectively deposited on polypropylene (PP) fibers. The virucidal properties of the AgCu nanofilm were evaluated by comparing the viral loads remaining on uncoated and coated PP after contact times between 2 and 24 h. Quantification of virion numbers for different initial concentrations indicated a reduction of more than 95% after 2 h of contact. The bactericidal action of the AgCu nanofilm was also confirmed by inoculating uncoated and coated PP with a pool of pathogenic bacteria associated with pneumonia (ESKAPE). Meanwhile, no cytotoxicity was observed for human fibroblasts and keratinocyte cells, indicating that the nanofilm could be in contact with human skin without threat. The deposition of the AgCu nanofilm on the nonwoven component of reusable cloth masks might help to prevent virus and bacterial infection while reducing the pollution burden related to the disposable masks. The possible mechanism of biocide contact action was studied by quantum chemistry calculations that show that the addition of Ag and/or Cu makes the polymeric fiber a better electron acceptor. This can promote the oxidation of the phospholipids present at both the virus and bacterial membranes. The rupture at the membrane exposes and damages the genetic material of the virus. More studies are needed to determine the mechanism of action, but the results reported here indicate that Cu and Ag ions are good allies, which can help protect us from the virus that has caused this disturbing pandemic.

Investigation of the stability and risks of fomite transmission of human coronavirus OC43 on leather.

Limited research exists on the potential for leather to act as a fomite of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) or endemic coronaviruses including human coronavirus (HCoV) OC43; this is important for settings such as the shoe manufacturing industry. Antiviral coating of leather hides could limit such risks. This study aimed to investigate the stability and transfer of HCoVOC43 on different leathers, as a surrogate for SARS-CoV-2, and assess the antiviral efficacy of a silver-based leather coating. The stability of HCoV-OC43 (6.6 log10) on patent, full-grain calf, corrected grain finished and nubuck leathers (silver additive-coated and uncoated) was measured by titration on BHK-21 cells. Transfer from leather to cardboard and stainless steel was determined. HCoV-OC43 was detectable for 6 h on patent, 24 h on finished leather and 48 h on calf leather; no infectious virus was recovered from nubuck. HCoV-OC43 transferred from patent, finished and calf leathers onto cardboard and stainless steel up to 2 h post-inoculation (≤3.1-5.5 log10), suggesting that leathers could act as fomites. Silver additive-coated calf and finished leathers were antiviral against HCoV-OC43, with no infectious virus recovered after 2 h and limited transfer to other surfaces. The silver additive could reduce potential indirect transmission of HCoV-OC43 from leather.

Long-term antimicrobial effectiveness of a silver-impregnated foil on high-touch hospital surfaces in patient rooms.

BACKGROUND: The hospital environment has got more attention as evidence as source for bacterial transmission and subsequent hospital-acquired infection increased. Regular cleaning and disinfection have been proposed to lower the risk of infection, in particular for gram-positive bacteria. Auto-disinfecting surfaces would allow to decrease survival of pathogens, while limiting resource to achieve a safe environment in patient rooms. METHODS: A controlled trial to evaluate the antimicrobial effectiveness of a polyvinyl chloride foil containing an integrated silver-based agent (containing silver ions 2%) on high-touch surfaces in patient rooms. RESULTS: The overall log reduction of the mean values was 1.8 log10 CFU, the median 0.5 log10 CFU comparing bioburden of control vs antimicrobial foil (p < 0.01). Important pathogens were significantly less likely recovered from the foil, in particular enterococci. These effects were present even after 6 months of in-use. CONCLUSIONS: A foil containing an integrated silver-based agent applied to high-touch surfaces effectively results in lower recovery of important pathogens from such surfaces over a 6-month study period.

Biogenic and biocompatible silver nanoparticles for an apoptotic anti-ovarian activity and as polydopamine-functionalized antibiotic carrier for an augmented antibiofilm activity.

Silver nanoparticles (AgNPs) could be employed in the combat against COVID-19, yet are associated with toxicities. In this study, biogenic and biocompatible AgNPs using the agro-waste, non-edible Hibiscus sabdariffa stem were synthesized. Under optimized reaction conditions, synthesized green AgNPs were crystalline, face cubic centered, spherical with a diameter of around 17 nm and a surface charge of -20 mV. Their murine lethal dose 50 (LD50) was 4 folds higher than the chemical AgNPs. Furthermore, they were more murine hepato- and nephro-tolerated than chemical counterparts due to activation of Nrf-2 and HO-1 pathway. They exerted an apoptotic anti-ovarian cancer activity with IC50 value 6 times more than the normal cell line. Being functionalized with polydopamine and conjugated to either moxifloxacin or gatifloxacin, the conjugates exerted an augmented antibiofilm activity against Klebsiella pneumoniae, Pseudomonas aeruginosa, and Acinetobacter baumannii biofilms that was significantly higher than antibiotic alone or functionalized AgNPs suggesting a synergistic activity. In conclusion, this study introduced a facile one-pot synthesis of biogenic and biocompatible AgNPs with preferential anti-cancer activity and could be utilized as antibiotic delivery system for a successful eradication of Gram-negative biofilms.