User acceptability of saliva and gargle samples for identifying COVID-19 positive high-risk workers and household contacts

Throughout the COVID-19 pandemic nasopharyngeal or nose and/or throat swabs (NTS) have been the primary approach for collecting patient samples for the subsequent detection of viral RNA. However, this procedure, if undertaken correctly, can be unpleasant and therefore deters individuals from providing high quality samples. To overcome these limitations other modes of sample collection have been explored. In a cohort of frontline health care workers we have compared saliva and gargle samples to gold-standard NTS. 93% of individuals preferred providing saliva or gargle samples, with little sex-dependent variation. Viral titers collected in samples were analyzed using standard methods and showed that gargle and saliva were similarly comparable for identifying COVID-19 positive individuals compared to NTS (92% sensitivity; 98% specificity). We suggest that gargle and saliva collection are viable alternatives to NTS swabs and may encourage testing to provide better disease diagnosis and population surveillance

Measurement of SARS-CoV-2 in air and on surfaces in Scottish hospitals

BackgroundThere are still uncertainties in our knowledge of the amount of SARS-CoV-2 virus present in the environment; where it can be found, and potential exposure determinants, limiting our ability to effectively model and compare interventions for risk management.AimThis study measured SARS-CoV-2 in three hospitals in Scotland on surfaces and air, alongside ventilation and patient care activities.MethodsAir sampling at 200 L/min for 20 minutes and surface sampling were performed in two wards designated to treat COVID-19 -positive patients and two non-COVID-19 wards across three hospitals in November and December 2020. FindingsDetectable samples of SARS-CoV-2 were found in COVID-19 treatment wards but not in non-COVID-19 wards. Most samples were below assay detection limits, but maximum concentrations reached 1.7x10 3 genomic copies/m3 in air and 1.9x10 4 copies per surface swab (3.2x10 2 copies/cm2 for surface loading). The estimated geometric mean air concentration (geometric standard deviation) across all hospitals was 0.41 (71) genomic copies/m3 and the corresponding values for surface contamination were 2.9 (29) copies/swab. SARS-CoV-2 RNA was found in non-patient areas (patient/visitor waiting rooms and personal protective equipment (PPE) changing areas) associated with COVID-19 treatment wards.ConclusionsNon-patient areas of the hospital may pose risks for infection transmission and further attention should be paid to these areas. Standardization of sampling methods will improve understanding of levels of environmental contamination. The pandemic has demonstrated a need to review and act upon the challenges of older hospital buildings meeting current ventilation guidance

Nanopropulsion by biocatalytic self-assembly

A number of organisms and organelles are capable of self-propulsion at the micro- and nanoscales. Production of simple man-made mimics of biological transportation systems may prove relevant to achieving movement in artificial cells and nano/micronscale robotics that may be of biological and nanotechnological importance. We demonstrate the propulsion of particles based on catalytically controlled molecular self-assembly and fiber formation at the particle surface. Specifically, phosphatase enzymes (acting as the engine) are conjugated to a quantum dot (the vehicle), and are subsequently exposed to micellar aggregates (fuel) that upon biocatalytic dephosphorylation undergo fibrillar self-assembly, which in turn causes propulsion. The motion of individual enzyme/quantum dot conjugates is followed directly using fluorescence microscopy. While overall movement remains random, the enzymeconjugates exhibit significantly faster transport in the presence of the fiber forming system, compared to controls without fuel, a non-self-assembling substrate, or a substrate which assembles into spherical, rather than fibrous structures upon enzymatic dephosphorylation. When increasing the concentration of the fiber-forming fuel, the speed of the conjugates increases compared to non-self-assembling substrate, although directionality remains random

Nanopropulsion by Biocatalytic Self-Assembly

A number of organisms and organelles are capable of self-propulsion at the micro- and nanoscales. Production of simple man-made mimics of biological transportation systems may prove relevant to achieving movement in artificial cells and nano/micronscale robotics that may be of biological and nanotechnological importance. We demonstrate the propulsion of particles based on catalytically controlled molecular self-assembly and fiber formation at the particle surface. Specifically, phosphatase enzymes (acting as the engine) are conjugated to a quantum dot (the vehicle), and are subsequently exposed to micellar aggregates (fuel) that upon biocatalytic dephosphorylation undergo fibrillar self-assembly, which in turn causes propulsion. The motion of individual enzyme/quantum dot conjugates is followed directly using fluorescence microscopy. While overall movement remains random, the enzyme–conjugates exhibit significantly faster transport in the presence of the fiber forming system, compared to controls without fuel, a non-self-assembling substrate, or a substrate which assembles into spherical, rather than fibrous structures upon enzymatic dephosphorylation. When increasing the concentration of the fiber-forming fuel, the speed of the conjugates increases compared to non-self-assembling substrate, although directionality remains random

Measurement of SARS-CoV-2 in air and on surfaces in Scottish hospitals

BackgroundThere are still uncertainties in our knowledge of the amount of SARS-CoV-2 virus present in the environment; where it can be found, and potential exposure determinants, limiting our ability to effectively model and compare interventions for risk management.AimThis study measured SARS-CoV-2 in three hospitals in Scotland on surfaces and air, alongside ventilation and patient care activities.MethodsAir sampling at 200 L/min for 20 minutes and surface sampling were performed in two wards designated to treat COVID-19 -positive patients and two non-COVID-19 wards across three hospitals in November and December 2020. FindingsDetectable samples of SARS-CoV-2 were found in COVID-19 treatment wards but not in non-COVID-19 wards. Most samples were below assay detection limits, but maximum concentrations reached 1.7x10 3 genomic copies/m3 in air and 1.9x10 4 copies per surface swab (3.2x10 2 copies/cm2 for surface loading). The estimated geometric mean air concentration (geometric standard deviation) across all hospitals was 0.41 (71) genomic copies/m3 and the corresponding values for surface contamination were 2.9 (29) copies/swab. SARS-CoV-2 RNA was found in non-patient areas (patient/visitor waiting rooms and personal protective equipment (PPE) changing areas) associated with COVID-19 treatment wards.ConclusionsNon-patient areas of the hospital may pose risks for infection transmission and further attention should be paid to these areas. Standardization of sampling methods will improve understanding of levels of environmental contamination. The pandemic has demonstrated a need to review and act upon the challenges of older hospital buildings meeting current ventilation guidance