Molecular mechanisms behind the anti corona virus activity of small metal oxide nanoparticles.

The recent COVID-19 pandemic has set a strong quest for advanced understanding of possible tracks in abating and eliminating viral infections. In the view that several families of "pristine" small oxide nanoparticles (NPs) have demonstrated viricidal activity against SARS-CoV-2, we studied the effect of two NPs, with presumably different reactivity, on two viruses aiming to evaluate two "primary suspect" routes of their antiviral activity, either specific blocking of surface proteins or causing membrane disruption. The chosen NPs were non-photoactive 3.

Quantitative Assessment of Microbial Transmission onto Environmental Surfaces Using Thermoresponsive Gelatin Hydrogels as a Finger Mimetic under In Situ-Mimicking Conditions.

Surface-mediated transmission of pathogens plays a key role in healthcare-associated infections. However, proper techniques for its quantitative analysis are lacking, making it challenging to develop novel antimicrobial and anti-fouling surfaces to reduce pathogen spread via environmental surfaces. This study demonstrates a gelatin hydrogel-based touch transfer test, the HydroTouch test, to evaluate pathogen transmission on high-touch surfaces under semi-dry conditions.

Comparison of the activity of two elastin-like recombinant carriers fused to the antimicrobial peptide indolicidin.

Recombinant fusion biotechnology is a powerful tool for producing antimicrobial peptides (AMPs), which can contribute to limiting the number of potentially infectious microorganisms. AMPs are often expressed in fusion with a carrier protein, a strategy that prevents toxic effects on host bacterial cells and protects them from proteolytic degradation. Among the many fusion carriers available, elastin-like polypeptides offer several valuable advantages related to their unique thermo-responsive behavior.

Efficient Defect-Driven Cation Exchange beyond the Nanoscale Semiconductors toward Antibacterial Functionalization.

Defect engineering is an exciting tool for customizing semiconductors' structural and optoelectronic properties. Elaborating programmable methodologies to circumvent energy constraints in multievent inversions expands our understanding of the mechanisms governing the functionalization of nanomaterials. Herein, we introduce a novel strategy based on defect incorporation and solution rationalization, which triggers energetically unfavorable cation exchange reactions in extended solids.

Synthesis and Antibacterial Properties of Novel Quaternary Ammonium Lignins.

The ongoing demand for effective antimicrobial materials persists, and lignin emerges as a promising natural antibacterial material with renewable properties. The adaptability of lignin to various chemical modifications offers avenues to enhance its antimicrobial activity. Here, we employed chloromethylation and subsequent functionalization with variable tertiary alkyl dimethyl amines to produce C6-C18 quaternary ammonium lignins (QALs) from hardwood (aspen), softwood (pine), and grass (barley straw).

Reusable magnetic mixture of CuFeO-FeO and TiO for photocatalytic degradation of pesticides in water.

Photocatalysis is a promising treatment method to remove pollutants from water. TiO-P25 is a commercially available model photocatalyst, which very efficiently degrades organic pollutants under UVA light exposure. However, the collection and the recovery of TiO-P25 from cleaned water poses significant difficulties, severely limiting its usability.

Antibacterial activity of solid surfaces is critically dependent on relative humidity, inoculum volume, and organic soiling.

Antimicrobial surface materials potentially prevent pathogen transfer from contaminated surfaces. Efficacy of such surfaces is assessed by standard methods using wet exposure conditions known to overestimate antimicrobial activity compared to dry exposure. Some dry test formats have been proposed but semi-dry exposure scenarios e.

Antimicrobial Nano Coatings.

History has demonstrated that the uncontrolled fast thriving of potentially pathogenic microorganisms may lead to serious consequences and, thus, the approaches helping to control the microbial numbers in infectional hot-spots are necessary [...

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 (CeO). Two nano-CeO 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.

Effects of environmentally relevant concentrations of microplastics on amphipods.

Lack of microplastics (MP) toxicity studies involving environmentally relevant concentrations and exposure times is concerning. Here we analyzed the potential adverse effects of low density polyethylene (LDPE) MP at environmentally relevant concentration in sub-chronic exposure to two amphipods Gmelinoides fasciatus and Gammarus lacustris, species that naturally compete with each other for their habitats. 14-day exposure to 2 μg/L (8 particles/L corresponding to low exposure) and 2 mg/L (∼8400 particles/L, corresponding to high exposure) of 53-100 μm LDPE MP were used to assess ingestion and egestion of MP, evaluate its effects on amphipod mortality, swimming ability and oxidative stress level.

Hazard of polystyrene micro-and nanospheres to selected aquatic and terrestrial organisms.

Plastics contamination in the environment is a major concern. Risk assessment of micro- and nanoplastics (MPL and NPL) poses significant challenges due to MPL and NPL heterogeneity regarding compositional polymers, particle sizes and morphologies in the environment. Yet, there exists considerable toxicological literature on commercial polystyrene (PS) micro- and nanospheres.

Preparation and Characterization of Photocatalytically Active Antibacterial Surfaces Covered with Acrylic Matrix Embedded Nano-ZnO and Nano-ZnO/Ag.

In the context of healthcare-acquired infections, microbial cross-contamination and the spread of antibiotic resistance, additional passive measures to prevent pathogen carryover are urgently needed. Antimicrobial high-touch surfaces that kill microbes on contact or prevent their adhesion could be considered to mitigate the spread. Here, we demonstrate that photocatalytic nano-ZnO- and nano-ZnO/Ag-based antibacterial surfaces with efficacy of at least a 2.

Cellular binding, uptake and biotransformation of silver nanoparticles in human T lymphocytes.

Our knowledge of uptake, toxicity and detoxification mechanisms as related to nanoparticles' (NPs') characteristics remains incomplete. Here we combine the analytical power of three advanced techniques to study the cellular binding and uptake and the intracellular transformation of silver nanoparticles (AgNPs): single-particle inductively coupled mass spectrometry, mass cytometry and synchrotron X-ray absorption spectrometry. Our results show that although intracellular and extracellularly bound AgNPs undergo major transformation depending on their primary size and surface coating, intracellular Ag in 24 h AgNP-exposed human lymphocytes exists in nanoparticulate form.

Selective antibiofilm properties and biocompatibility of nano-ZnO and nano-ZnO/Ag coated surfaces.

Spread of pathogenic microbes and antibiotic-resistant bacteria in health-care settings and public spaces is a serious public health challenge. Materials that prevent solid surface colonization or impede touch-transfer of viable microbes could provide means to decrease pathogen transfer from high-touch surfaces in critical applications. ZnO and Ag nanoparticles have shown great potential in antimicrobial applications.

Selection of resistance by antimicrobial coatings in the healthcare setting.

Antimicrobial touch surfaces have been introduced in healthcare settings with the aim of supporting existing hygiene procedures, and to help combat the increasing threat of antimicrobial resistance. However, concerns have been raised over the potential selection pressure exerted by such surfaces, which may drive the evolution and spread of antimicrobial resistance. This review highlights studies that indicate risks associated with resistance on antimicrobial surfaces by different processes, including evolution by de-novo mutation and horizontal gene transfer, and species sorting of inherently resistant bacteria dispersed on to antimicrobial surfaces.

Correction to: Quantitative Measurement of Cell-Nanoparticle Interactions Using Mass Cytometry.

This chapter was inadvertently published with the acknowledgement section leaving out the following sentence: "This work received funding from South Australian Government PRIF program Project "International Cluster on Nanosafety" of Nicolas H. Voelcker and Enzo Lombi." This correction has been updated in the chapter.

Quantitative Measurement of Cell-Nanoparticle Interactions Using Mass Cytometry.

Mass cytometry is a technique that uses inductively coupled plasma mass spectrometry (ICP-MS) to quantify the isotopic composition of cells in suspension. Traditionally it has been used in conjunction with antibodies labeled with stable lanthanide isotopes to investigate cellular heterogeneity. Here we describe its use to quantify uptake of metal nanoparticles by cells in suspension.

Propidium iodide staining underestimates viability of adherent bacterial cells.

Combining membrane impermeable DNA-binding stain propidium iodide (PI) with membrane-permeable DNA-binding counterstains is a widely used approach for bacterial viability staining. In this paper we show that PI staining of adherent cells in biofilms may significantly underestimate bacterial viability due to the presence of extracellular nucleic acids (eNA). We demonstrate that gram-positive Staphylococcus epidermidis and gram-negative Escherichia coli 24-hour initial biofilms on glass consist of 76 and 96% PI-positive red cells in situ, respectively, even though 68% the cells of either species in these aggregates are metabolically active.

Potential ecotoxicological effects of antimicrobial surface coatings: a literature survey backed up by analysis of market reports.

This review was initiated by the COST action CA15114 AMICI "Anti-Microbial Coating Innovations to prevent infectious diseases," where one important aspect is to analyze ecotoxicological impacts of antimicrobial coatings (AMCs) to ensure their sustainable use. Scopus database was used to collect scientific literature on the types and uses of AMCs, while market reports were used to collect data on production volumes. Special attention was paid on data obtained for the release of the most prevalent ingredients of AMCs into the aqueous phase that was used as the proxy for their possible ecotoxicological effects.

Antimicrobial potency of differently coated 10 and 50 nm silver nanoparticles against clinically relevant bacteria Escherichia coli and Staphylococcus aureus.

Silver nanoparticles (nanoAg) are effective antimicrobials and promising alternatives to traditional antibiotics. This study aimed at evaluating potency of different nanoAg against healthcare infections associated bacteria: Gram-negative Escherichia coli and Gram-positive Staphylococcus aureus. A library of differently coated nanoAg of two different sizes (10 and 50 nm) were prepared using coating agents poly-L-Lysine (PLL), cetyltrimethyl-ammonium bromide (CTAB), citrate (CIT), polyvinyl-pyrrolidone (PVP), polysorbate 80 (Tween 80), and dioctyl-sodium sulfosuccinate (AOT).

Rapid in situ assessment of Cu-ion mediated effects and antibacterial efficacy of copper surfaces.

Release of metal ions from metal-based surfaces has been considered one of the main drivers of their antimicrobial activity. Here we describe a method that enables parallel assessment of metal ion release from solid metallic surfaces and antimicrobial efficacy of these surfaces in a short time period. The protocol involves placement of a small volume of bioluminescent bacteria onto the tested surface and direct measurement of bioluminescence at various time points.

UVA-induced antimicrobial activity of ZnO/Ag nanocomposite covered surfaces.

Application of efficient antimicrobial surfaces has been estimated to decrease both, the healthcare-associated infections and the spread of antibiotic-resistant bacteria. In this paper, we prepared ZnO and ZnO/Ag nanoparticle covered surfaces and evaluated their antimicrobial efficacy towards a Gram-negative bacterial model (Escherichia coli), a Gram-positive bacterial model (Staphylococcus aureus) and a fungal model (Candida albicans) in the dark and under UVA illumination. The surfaces were prepared by spin coating aliquots of ZnO and ZnO/Ag nanoparticle suspensions onto glass substrates.

Ligand-Doped Copper Oxo-hydroxide Nanoparticles are Effective Antimicrobials.

Bacterial resistance to antimicrobial therapies is an increasing clinical problem. This is as true for topical applications as it is for systemic therapy. Topically, copper ions may be effective and cheap antimicrobials that act through multiple pathways thereby limiting opportunities to bacteria for resistance.