Photothermal inactivation of universal viral particles by localized surface plasmon resonance mediated heating filter membrane.

This study introduces localized surface plasmon resonance (L-SPR) mediated heating filter membrane (HFM) for inactivating universal viral particles by using the photothermal effect of plasmonic metal nanoparticles (NPs). Plasmonic metal NPs were coated onto filter membrane via a conventional spray-coating method. The surface temperature of the HFM could be controlled to approximately 40-60 °C at room temperature, owing to the photothermal effect of the gold (Au) NPs coated on them, under irradiation by visible light-emitting diodes. Due to the photothermal effect of the HFMs, the virus titer of H1Npdm09 was reduced by > 99.9%, the full inactivation time being < 10 min, confirming the 50% tissue culture infective dose (TCID50) assay. Crystal violet staining showed that the infectious samples with photothermal inactivation lost their infectivity against Mardin-Darby Canine Kidney cells. Moreover, photothermal inactivation could also be applied to reduce the infectivity of SARS-CoV-2, showing reduction rate of 99%. We used quantitative reverse transcription polymerase chain reaction (qRT-PCR) techniques to confirm the existence of viral genes on the surface of the HFM. The results of the TCID50 assay, crystal violet staining method, and qRT-PCR showed that the effective and immediate reduction in viral infectivity possibly originated from the denaturation or deformation of membrane proteins and components. This study provides a new, simple, and effective method to inactivate viral infectivity, leading to its potential application in various fields of indoor air quality control and medical science.

Energy-efficient PM adhesion method using functional electroactive nanofibers

With growing environmental pollution caused in part by increase in particulate matter (PM), indoor air quality is becoming an important issue in modern society particularly as health and environment consciousness rises. In addition, as the need for a mask has emerged to prevent the spread of viruses such as the SARS-CoV-2 virus that causes the dreaded COVID-19, filter technology has become the focus of considerable research attention. In this study, we introduce a functional fiber that can improve the energy-efficiency for PM adhesion while lowering the pressure drop in an existing commercial high-efficiency particulate absorbing (HEPA) filter. Nanofibers made of polymer and metal nanoparticles were produced by electrospinning;the triboelectricity generated by friction between fibers and air was used to capture the PM. The PM adhesion performance and pressure loss of the developed filter (PVDF/Au) and the commercial HEPA filter were compared, and the charging effect of the filters was analyzed by comparing the power generation performance of the triboelectric nanogenerator. Compared to HEPA filter, PVDF/Au filter reduced pressure drop by about 25%, but, the PM adhesion-energy efficiency of PVDF/Au was superior to that of HEPA by 28.6% based on 90% PM2.5 removal. As a filter that increases the PM adhesion effect while lowering the energy consumption and the pressure drop of the filter, PVDF/Au is expected to be effectively utilized in the existing filtration type filter system.

Nutritional status of patients with COVID-19.

The relationship between immunity and nutrition is well known and its role in coronavirus disease 2019 (COVID-19) is also being paid great attention. However, the nutritional status of COVID-19 patients is unknown. Vitamin B1, B6, B12, vitamin D (25-hydroxyvitamin D), folate, selenium, and zinc levels were measured in 50 hospitalized patients with COVID-19. Overall, 76% of the patients were vitamin D deficient and 42% were selenium deficient. No significant increase in the incidence of deficiency was found for vitamins B1, B6, and B12, folate, and zinc in patients with COVID-19. The COVID-19 group showed significantly lower vitamin D values than the healthy control group (150 people, matched by age/sex). Severe vitamin D deficiency (based on a cut-off of ≤10 ng/dl) was found in 24.0% of the patients in the COVID-19 group and 7.3% in the control group. Among 12 patients with respiratory distress, 11 (91.7%) were deficient in at least one nutrient. However, patients without respiratory distress showed a deficiency in 30/38 cases (78.9%; p = 0.425). These results suggest that a deficiency of vitamin D or selenium may decrease the immune defenses against COVID-19 and cause progression to severe disease. However, more precise and large-scale studies are needed.