Antiviral Nanostructures That Reduce the Viability of Coronaviruses SARS-CoV-2 and HCoV-NL63

Background: The rapid emergence and global spread of the COVID-19 causing Severe Acute Respiratory Syndrome Coronavirus-2 (SARS-CoV-2) and its subsequent mutated strains, has caused unprecedented health, economic and social devastation. Respiratory viruses can be transmitted through both direct and indirect channels, including aerosol respiratory droplets and contamination of inanimate surfaces. Current methods of virus inactivation on surfaces include chemicals and biocides and while effective, continuous, and repetitive cleaning of all surfaces is not always viable. Recent work in the field of biomaterials engineering has established the antibacterial effects of hydrothermally synthesised TiO2 nanostructured surfaces against both Gram-negative and positive bacteria. This study investigates the effectiveness of TiO2 nanostructured surfaces against two human coronaviruses: SARS-CoV-2 and HCoV-NL63 for surface-based inactivation. Results: Results show that structured surfaces reduced live infectious viral loads of SARS-CoV-2 and HCoV-NL63 by 5 log and 3 log, respectively after 5 hours compared to non-structured surfaces. Interestingly, infectious virus remained present on the control plastic surface after 7 hours exposure.Conclusions: These encouraging results establish the potential use of nanostructured surfaces to reduce the transmission and spread of coronaviruses, by reducing the virus’ infectious period on a surface. The dual antiviral and antibacterial properties of these surfaces give them potential application in high-risk environments such as hospitals and healthcare settings.

Lethal and Sublethal Responses of Hydropsyche pellucidula (Insecta, Trichoptera) to Commercial Polypropylene Microplastics after Different Preconditioning Treatments

Microplastics (MPs) pose biological and chemical hazards in aquatic and terrestrial food webs across the globe. Research on microplastic contamination has long focused on marine ecosystems, whereas the toxicological impact on freshwater organisms is still little explored. In this study, the lethal and sublethal response of the freshwater macroinvertebrate Hydropsyche pellucidula exposed to polypropylene MPs after different pre-conditioning treatments was assessed. Field samples were collected in a riverine system (Vipacco river; northeast Italy) to assess the characteristics of the MPs in the aquatic environment Both water and sediment were contaminated by MPs (3.73 ± 2.11 items m−3 per min and 3.33 ± 4.16 items dm−3, respectively). The chemical MPs composition included polystyrene, polyethylene terephthalate, polyurethane, polyamide, polypropylene, and polyethylene. Polypropylene (PP), although not the most abundant polymer recorded in the study area, was preferred over the other types according to its abundance in freshwater and H. pellucidula feeding behavior. A housing test was performed to recreate the natural conditions of larvae sampled for a reliable response to the ecotoxicological tests. The microplastics underwent either preconditioning with Vipacco River water (PP-river) and surfactant Triton X-100 (PP-sf) or no pre-treatment (PP). Submersion of microplastics in 10 µg L−1 of surfactant solution for 24 h was sufficient to induce consistent spectral changes and modify the chemical profile of the plastic surface. Mortality rate differed according to treatment: PP and PP-river > positive control > PP-sf > negative control. Integrated biomarker response (IBRv2) and analysis of oxidative stress biomarker levels showed a greater response of superoxide dismutase and lipid peroxidation (malondialdehyde) in larvae treated with PP conditioned in surfactant. Our findings enhance knowledge on the toxicity of PP and conditioning phases on H. pellucidula larvae.

Observational Evidence and Open Questions on the Role of Internal Tidal Waves on the Concentration and Transport of Floating Plastic Debris

Tidal currents flowing over benthic relief (e.g., banks, shelf break) can produce large internal waves. These waves propagate away from their origin and are capable of crossing the continental shelf and seas. Studies of shoreward transport of larval invertebrates and fish by these internal waves unintentionally tested whether they can capture, concentrate and transport floating plastic. Plastic surface drifters deployed in front of sets of internal wave convergences were often captured (>90% captured) and transported kilometers by the waves. There are, however, few investigations into how internal tidal waves may affect the fate and distribution of floating plastic waste. A number of areas of future research are suggested: (1) How much floating plastic is found in internal wave convergences? (2) How buoyant must floating plastic be to be captured by internal waves? (3) Why did only some sets of internal waves cause concentration and transport of surface material? (4) Do concentration and transport of floating plastic vary over the spring/neap tidal cycle? (5) Do seasonal changes in the depth of the pycnocline alter the transport of floating plastic by internal waves? (6) Plastic debris deposited on shore may not be evenly distributed, but may be more abundant landward of sites on the shelf break that more readily generate large internal waves. (7) Internal waves that travel long distances (10–100 s of km) have the potential to accumulate large amounts of plastic debris. (8) At locations where internal waves cross the continental shelf, how far offshore does transport commence?

Bone Diagenesis in Short Timescales: Insights from an Exploratory Proteomic Analysis

The evaluation of bone diagenetic phenomena in archaeological timescales has a long history; however, little is known about the origins of the microbes driving bone diagenesis, nor about the extent of bone diagenesis in short timeframes—such as in forensic contexts. Previously, the analysis of non-collagenous proteins (NCPs) through bottom-up proteomics revealed the presence of potential biomarkers useful in estimating the post-mortem interval (PMI). However, there is still a great need for enhancing the understanding of the diagenetic processes taking place in forensic timeframes, and to clarify whether proteomic analyses can help to develop better models for estimating PMI reliably. To address these knowledge gaps, we designed an experiment based on whole rat carcasses, defleshed long rat bones, and excised but still-fleshed rat limbs, which were either buried in soil or exposed on a clean plastic surface, left to decompose for 28 weeks, and retrieved at different time intervals. This study aimed to assess differences in bone protein relative abundances for the various deposition modalities and intervals. We further evaluated the effects that extrinsic factors, autolysis, and gut and soil bacteria had on bone diagenesis via bottom-up proteomics. Results showed six proteins whose abundance was significantly different between samples subjected to either microbial decomposition (gut or soil bacteria) or to environmental factors. In particular, muscle- and calcium-binding proteins were found to be more prone to degradation by bacterial attack, whereas plasma and bone marrow proteins were more susceptible to exposure to extrinsic agents. Our results suggest that both gut and soil bacteria play key roles in bone diagenesis and protein decay in relatively short timescales, and that bone proteomics is a proficient resource with which to identify microbially-driven versus extrinsically-driven diagenesis.

Higher concentrations of bacterial enveloped virus Phi6 can protect the virus from environmental decay

Phage Phi6 is an enveloped virus considered as a possible non-pathogenic surrogate for SARS-CoV-2 and other viral pathogens in transmission studies. Higher input amounts of bacteriophage Phi6 are shown to delay and protect the phage from environmental decay, both when the phage are dried in plastic tubes, and when they are stored in saline solution at 4°C. When bacteriophage Phi6 are placed in LB (Luria-Bertani) growth medium prior to placement on the plastic surface, viral recovery is not influenced by the starting concentration. The protection is reflected in longer half-lives of the phage at higher concentrations compared to lower. Because experiments supporting the possibility of fomite transmission of SARS-CoV-2 and other viruses rely upon survival of infectious virus following inoculation of various surfaces, high initial amounts of input virus on a surface may generate artificially inflated survival times compared to realistic lower levels of virus that a subject would normally encounter. This is not only because there are extra half-lives to go through at the higher concentrations, but also because the half-lives themselves are extended at the higher virus concentrations. It is important to design surface drying experiments for pathogens with realistic levels of input virus, and to consider the role of the carrier and matrix if the results are to be clinically relevant.