Electrochemical capacitance spectroscopy based determination of antibodies against SARS-CoV-2 virus spike protein.

In this study, we are reporting a novel electrochemical capacitance spectroscopy (ECS) platform designed for the sensitive and label-free detection of antibodies against severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) virus spike protein (anti-rS) in diluted blood serum. The determination of anti-rS is crucial for identification individuals who have been infected by SARS-CoV-2 virus and may have acquired immunity. The rS protein was immobilized on a screen-printed carbon electrode, which was incubated in diluted blood serum containing anti-rS antibodies. Label-free ECS was applied for the determination of interaction between immobilized rS and free-standing anti-rS. Here reported bioanalytical platform demonstrated high sensitivity and specificity in detecting anti-rS, achieving a limit of detection of 4.38 nM. This versatile platform could be further enhanced by applying various electrode materials and adapting this platform to detect antibodies against some other proteins. Our findings have significant implications for the development of affordable, scalable biosensing platforms capable to provide rapid and accurate public health screening and monitoring, particularly in the context of the coronavirus disease 2019 (COVID-19) pandemic.

Assessment of Rhizobium anhuiense Bacteria as a Potential Biocatalyst for Microbial Biofuel Cell Design.

The development of microbial fuel cells based on electro-catalytic processes is among the novel topics, which are recently emerging in the sustainable development of energetic systems. Microbial fuel cells have emerged as unique biocatalytic systems, which transform the chemical energy accumulated in renewable organic fuels and at the same time reduce pollution from hazardous organic compounds. However, not all microorganisms involved in metabolic/catalytic processes generate sufficient redox potential. In this research, we have assessed the applicability of the microorganism Rhizobium anhuiense as a catalyst suitable for the design of microbial fuel cells. To improve the charge transfer, several redox mediators were tested, namely menadione, riboflavin, and 9,10-phenanthrenequinone (PQ). The best performance was determined for a Rhizobium anhuiense-based bio-anode mediated by menadione with a 0.385 mV open circuit potential and 5.5 µW/cm2 maximal power density at 0.35 mV, which generated 50 µA/cm2 anode current at the same potential.

Electronic Cigarettes Are as Toxic to Skin Flap Survival as Tobacco Cigarettes.

PURPOSE: Electronic cigarettes (e-cigarettes) have become increasingly popular. However, information about the health risks associated with e-cigarette use is sparse. Currently, no published studies examine the effects of chronic e-cigarette exposure on microcirculation or perfusion. Using a rat skin flap model, we examined the toxic microcirculatory effects e-cigarettes may have in comparison with tobacco cigarettes. METHODS: Fifty-eight rats were randomized to either exposure to room air, tobacco cigarette smoke, medium-nicotine content (1.2%) e-cigarette vapor, or a high-nicotine content (2.4%) e-cigarette vapor. After 4 weeks of exposure, a random pattern, 3 × 9 cm skin flap was elevated on the dorsum of the rats. At 5 weeks, flap survival was evaluated quantitatively, and the rats were euthanized. Plasma was collected for nicotine and cotinine analysis, and flap tissues were harvested for histopathological analysis. RESULTS: Evaluation of the dorsal skin flaps demonstrated significantly increased necrosis in the vapor and tobacco groups. The average necrosis within the groups was as follows: control 19.23%, high-dose vapor 28.61%, medium-dose vapor 35.93%, and tobacco cigarette 30.15%. Although the e-cigarette and tobacco cigarette groups did not differ significantly, each individual group had significantly more necrosis than the control group (P<0.05). These results were corroborated with histopathological analysis of hypoxic tissue. CONCLUSIONS: Both the medium-content and high-nicotine content e-cigarette exposure groups had similar amounts of flap necrosis and hypoxia when compared with the tobacco cigarette exposure group. Nicotine-containing e-cigarette vapor is similarly toxic to skin flap survival as tobacco cigarettes.