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The SARS-CoV-2 pandemic required global efforts to create new protection and sterilization strategies. The sterilizing capacity of some metals is widespread. Copper (Cu) is one of the most studied due to its ability to inactivate viral agents, low cost, and ease of processing. This work evaluated the self-sterilizing capacity of Cu layers electrodeposited with two solutions – H2SO4/CuSO4 and HCl. Virucidal activity tests were performed with Mouse hepatitis virus 3 (MHV-3), a surrogate for SARS-CoV-2. The coating produced using HCl (dendritic surface structures) led to viral inactivation in 4 h. Conversely, the coating produced using H2SO4/CuSO4 (equiaxed surface morphology) required 24 h to achieve viral inactivation.

The development of a convenient, sensitive, rapid and self-sterilizing biosensor for microbial detection is important for the prevention and control of foodborne diseases. Herein, we designed a surface-enhanced Raman scattering (SERS) sensing nanoplatform based on a capture–enrichment–enhancement strategy to detect bacteria. The gold−Azo@silver−cetyltrimethylammonium bromide (Au−Azo@Ag−CTAB) SERS nanotags were obtained by optimizing the synthesis process conditions. The results showed that the modification of CTAB enabled the nanotags to bind to different bacteria electrostatically. This SERS sensing nanoplatform was demonstrated to be fast (15 min), accurate and sensitive (limit of detection (LOD): 300 and 400 CFU/mL for E. coli and S. aureus, respectively). Of note, the excellent endogenous antibacterial activity of CTAB allowed the complete inactivation of bacteria after the assay process, thus effectively avoiding secondary contamination. [ABSTRACT FROM AUTHOR]

Metal nanoparticles (NPs) are increasingly being used in many areas, e.g., industry, pharmacy, and biomedical engineering. NPs can be obtained through chemical and biological synthesis or using physical methods. AgNPs, AuNPs, CuNPs, FeNPs, MgNPs, SnO2NPs, TiO2NPs, and ZnONPs are the most commonly synthesized metal nanoparticles. Many of them have anti-microbial properties and documented activity supported by many tests against some species of pathogenic bacteria, viruses, and fungi. AgNPs, which are used for the production of commercial self-sterilizing packages, are one of the best-explored nanoparticles. Moreover, the EFSA has approved the use of small doses of silver nanoparticles (0.05 mg Ag·kg−1) to food products. Recent studies have shown that metal NPs can be used for the production of coatings to prevent the spread of the SARS-CoV-2 virus, which has caused the global pandemic. Some nanoparticles (e.g., ZnONPs and MgONPs) have the Generally Recognized As Safe (GRAS) status, i.e., they are considered safe for consumption and can be used for the production of edible coatings, protecting food against spoilage. Promising results have been obtained in research on the use of more than one type of nanometals, which prevents the development of pathogen resistance through various mechanisms of inactivation thereof. [ABSTRACT FROM AUTHOR]

The development of a convenient, sensitive, rapid and self-sterilizing biosensor for microbial detection is important for the prevention and control of foodborne diseases. Herein, we designed a surface-enhanced Raman scattering (SERS) sensing nanoplatform based on a capture–enrichment–enhancement strategy to detect bacteria. The gold−Azo@silver−cetyltrimethylammonium bromide (Au−Azo@Ag−CTAB) SERS nanotags were obtained by optimizing the synthesis process conditions. The results showed that the modification of CTAB enabled the nanotags to bind to different bacteria electrostatically. This SERS sensing nanoplatform was demonstrated to be fast (15 min), accurate and sensitive (limit of detection (LOD): 300 and 400 CFU/mL for E. coli and S. aureus, respectively). Of note, the excellent endogenous antibacterial activity of CTAB allowed the complete inactivation of bacteria after the assay process, thus effectively avoiding secondary contamination.

Objectives/purpose: High-touch surfaces are a critical reservoir in the spread of nosocomial infections. Although disinfection and infection control protocols are well developed, they lack the ability to passively reduce the pathogenic load of high-touch surfaces. Copper and its alloys have been suggested as a surface that exhibit continuous biocidal effects. Antimicrobial studies on these surfaces are prevalent, while virucidal studies are not as well explored. The goal of this study was to first determine the virucidal activity of a copper–nickel–zinc alloy and to then examine the effect of soiling and virus preparation on virucidal activity. Methods: A baculovirus vector was used as an easily quantifiable model of an infectious enveloped animal cell virus. Droplets containing virus were deposited on surfaces and allowed to stay wet using humidity control or were dried onto the surface. Virus was then recovered from the surface and assayed for infectivity. To examine how the composition of the droplet affected the survival of the virus, 3 different soiling conditions were tested. The first two were recommended by the United States Environmental Protection Agency and the third consisted of cell debris resulting from virus amplification. Results: A copper–nickel–zinc alloy was shown to have strong virucidal effects for an enveloped virus. Copper, nickel, and zinc ions were all shown to leach from the alloy surface and are the likely cause of virucidal activity by this surface. Virucidal activity was achieved under moderate soiling but lost under high soiling generated by routine virus amplification procedures. The surface was able to repeatably inactivate dried virus droplets under moderate soiling conditions, but unable to do so for virus droplets kept wet using high humidity. Conclusion: Ion leaching was associated with virucidal activity in both wet and dried virus conditions. Soiling protected the virus by quenching metal ions, and not by inhibiting leaching. The composition of the solution containing virus plays a critical role in evaluating the virucidal activity of surfaces and surface coatings. [ABSTRACT FROM AUTHOR]

Microbiologically contaminated surfaces pose a severe threat to human health. Antibacterial coatings that effectively destroy pathogens in-situ under ambient conditions are candidates to overcome this issue. In this work, we report self-sterilizing lacquer coatings enabled by the addition of novel 2D Ti 3 C 2 T x MXene, showing excellent photocatalytic and antimicrobial properties. The prepared facile MXene-enriched formulations based on air-drying and UV-curable lacquer dispersions were used to coat the opaque plastic sheets. The Ti 3 C 2 T x MXene content was optimized to ensure a minimal agglomeration of flakes in a lacquer coating, as validated by stability, morphology, and structure analyses. We confirmed the uniform distribution of 2D Ti 3 C 2 T x MXene in the coatings with energy dispersive spectroscopy (EDS) mapping. Superior optical properties of the protective lacquer coatings, added with efficient light absorption, enabled their self-cleaning from the adsorbed methylene blue coloring contaminant. This photocatalytic activity was further utilized for antimicrobial action. Under dark conditions, the protective lacquer coatings showed biostatic properties while in simulated daylight conditions, they were self-sterilizing against potentially pathogenic model bacteria such as Escherichia coli and Staphylococcus aureus. Altogether, our findings gave promise for using MXenes in daily life applications. [Display omitted] • Ti 3 C 2 T x MXene enabled coatings with photocatalytic and antimicrobial properties. • Optimized MXene content ensured a minimal agglomeration of nanoflakes in a coating. • Superior optical properties allowed self-cleaning action from model contaminant. • Light-induced self-sterilizing feature ensured antimicrobial action. [ABSTRACT FROM AUTHOR]

Abstract: A photocatalyst was applied to a lancet for pricking the finger to obtain an antibacterial property. A photocatalytic and uniform nano-layer of titanium dioxide (TiO2) on the surface of the lancet (0.36mm×24.5mm) was formed by sputtering and annealed for crystallization of the TiO2 layer. By elementary analysis of the TiO2 layer, titanium and oxygen were detected. Next, for the estimation of the antibacterial properties resulting from the photocatalytic effect, the lancet was packed into a capillary tube filled with a suspension of Escherichia coli K-12 (non-spore-forming bacterium), and was continuously rolled in a continuous UV-irradiation system under black-light irradiation. Distinct antibacterial effects after irradiation at 0.5mWcm−2 for 45min were observed in the crystallized TiO2 layer on the lancet. Finally, lancing resistances obtained by pricking an artificial skin sheet were examined using control lancets, and lancets with an unannealed TiO2 layer or an annealed TiO2 layer. The results showed almost the same lancing resistances for the control (0.53±0N, n =3) and the lancet with an annealed TiO2 layer (0.51±0.018N), while the lancet with an unannealed TiO2 layer showed a high lancing resistance compared with the other lancets (0.62±0.05N). In conclusion, the lancet coated with a crystallized, velvety nano-layer of TiO2 obtained by annealing had antibacterial properties and a similar lancing resistance compared with the bare lancet, and showed potential for application in monitoring blood glucose in diabetes. [Copyright &y& Elsevier]

Hematogenous spread of infections from colonized central intravenous catheters or central lines is a long-recognized problem with infection rates of 2 and 6.8 per 1000 days, respectively. Besides, removal of severe microbial colonization of implanted biomaterials is still a challenge and usually requires invasive operations. Hence, on demand self-sterilizing materials are required to avoid explant of colonized biomaterials and improve patient compliance. Moreover, photoluminescence is needed to make trackable biomaterials, which can be easily monitored upon implanting them in the body. Here, we propose the incorporation of near infrared (NIR) sensitive red-emitting carbon nanodot (CDs) into a polymeric matrix to give rise to innovative biomaterials with self-tracking and photothermal antimicrobial abilities. We obtain a material which can be processed to obtain medical devices using different techniques, among which, for instance, electrospinning. Herein, a proof-of-concept preparation of electrospun scaffolds is reported as it is highly desired in biomedical applications. Beside to confer imaging properties to the scaffold, that would allow an easy control over the in vivo positioning of implanted biomaterials as well as its degradation state and grade of integration with the surrounding native tissues, thanks to the capability to convert NIR light into local heat CDs can be exploited to exert broad-spectrum antimicrobial effect toward several pathogens. The rise in temperature can be easily modulated by controlling the irradiation time to achieve both an in vitro self-sterilization of the device and eventually in vivo destabilization of the microbial colonization. This innovative biomaterial could successfully inhibit biofilm formation and might be used as a powerful tool to treat antibiotic-resistant nature of biofilm-related infections in implanted medical devices. Unlabelled Image • Carbon nanodot confers self-tracking and antimicrobial abilities to a biomaterial. • Conversion of NIR light into local heat for microbicidal effect • On demand biofilmicidal effect toward clinical isolated multiresistant pathogens [ABSTRACT FROM AUTHOR]

Dissolvable polymeric microneedles (DPMNs) are promising transdermal drug delivery systems with minimal invasiveness and improved patient compliance. Incorporation of a small amount of graphene oxide (GO) in the biocompatible polymers for microneedle fabrication results in important new DPMN properties, that is, dramatically enhanced mechanic strength (10-17 times at 500 mg/mL GO), improved moisture resistance, self-sterilization, antibacterial and anti-inflammatory properties (demonstrated in vitro), and near-infrared light-activated controlled drug release (demonstrated in vitro and in vivo), which were exploited for the transdermal delivery of the chemotherapeutic, HA15, to melanoma-bearing mouse models. These new properties improve their efficacy of transdermal drug delivery and ease of use, enhance their capability of controlled drug release, enlarge the scope of the polymers that can be used for DPMN fabrication, prevent microbial contamination during storage and transportation, and reduce infection risk in clinical applications.