It is widely claimed that native GOx undergoes direct electron transfer (DET) at nanostructured electrodes. In this paper we argue that the vast majority, if not all, of these claims are incorrect. ...We present results for GOx adsorbed on MWCNTs, a typical nanostructured electrode. We show that the surface redox peaks usually attributed to DET to GOx actually arise from flavin, and possibly catalase, impurities present in the as supplied commercial enzyme that are adsorbed at the electrode surface. We show that the observed response to glucose is due to enzymatic activity, but not electroactivity, of adsorbed GOx that catalyses the reaction of d-glucose with dissolved oxygen leading to a decrease in the oxygen reduction current that correlates with the glucose concentration.
As the SARS-CoV-2 pandemic unfolds across the globe, consistent themes are emerging with regard to aspects of SARS-CoV-2 infection and its associated disease entities in children. Overall, children ...appear to be less frequently infected by, and affected by, SARS-CoV-2 virus and the clinical disease COVID-19. Large epidemiological studies have revealed children represent less than 2% of the total confirmed COVID-19 cases, of whom the majority experience minimal or mild disease that do not require hospitalisation. Children do not appear to be major drivers of SARS-CoV-2 transmission, with minimal secondary virus transmission demonstrated within families, schools and community settings. There are several postulated theories regarding the relatively low SARS-CoV-2 morbidity and mortality seen in children, which largely relate to differences in immune responses compared to adults, as well as differences in angiotensin converting enzyme 2 distribution that potentially limits viral entry and subsequent inflammation, hypoxia and tissue injury. The recent emergence of a multisystem inflammatory syndrome bearing temporal and serological plausibility for an immune-mediated SARS-CoV-2-related disease entity is currently under investigation. This article summarises the current available data regarding SARS-CoV-2 and the paediatric population, including the spectrum of disease in children, the role of children in virus transmission, and host-virus factors that underpin the unique aspects of SARS-CoV-2 pathogenicity in children.
We report a waveguide-enhanced Raman spectroscopy (WERS) platform with alignment-tolerant under-chip grating input coupling. The demonstration is based on a 100-nm thick planar (slab) tantalum ...pentoxide (Ta2O5) waveguide and the use of benzyl alcohol (BnOH) and its deuterated form (d7- BnOH) as reference analytes. The use of grating couplers simplifies the WERS system by providing improved translational alignment tolerance, important for disposable chips, as well as contributing to improved Raman conversion efficiency. The use of non-volatile, non-toxic BnOH and d7-BnOH as chemical analytes results in easily observable shifts in the Raman vibration lines between the two forms, making them good candidates for calibrating Raman systems. The design and fabrication of the waveguide and grating couplers are described, and a discussion of further potential improvements in performance is presented.
Redox cycling (RC) is a powerful tool capable of amplifying faradaic currents in electroanalytical measurements, thus allowing an enhancement of sensitivity through fast multiple sequential oxidation ...and reduction reactions of a redox‐active analyte. Present state‐of‐the‐art RC devices are mostly based on planar electrode geometries either in 2D or 3D configurations, requiring cleanroom facilities and expensive microfabrication techniques. Here, the electrochemical elaboration and characterization of a 3D coaxial macroporous twin‐electrode is reported, obtained by following a low‐cost bottom‐up approach. A nanoengineered highly organized porous material is the basis for the design of two threaded cylindrical porous gold microelectrodes with a gap in the micrometer range that can be fine‐tuned. The potentials of the outer and inner electrodes are biased at values above and below the redox potential of the analyte so that a given molecule can participate several times in the electron exchange reaction by shuttling between both electrodes. The resulting signal amplification, combined with a straightforward synthesis strategy of the electrode architecture, allows envisioning numerous (bio)electroanalytical applications.
Following a low‐cost bottom‐up approach, two threaded porous cylindrical microelectrodes are generated in a coaxial configuration, which results in a very compact functional device for redox cycling. Efficient signal amplification of the analyte is obtained due to the small gap between the two electrodes, a high surface area, and confined geometry.
In Volume XV in the series "Advances in Electrochemical Science and Engineering" various leading experts from the field of electrochemical engineering share their insights into how different ...experimental and computational methods are used in transferring molecular-scale discoveries into processes and products. Throughout, the focus is on the engineering problem and method of solution, rather than on the specific application, such that scientists from different backgrounds will benefit from the flow of ideas between the various subdisciplines. A must-read for anyone developing engineering tools for the next-generation design and control of electrochemical process technologies, including chemical, mechanical and electrical engineers, as well as chemists, physicists, biochemists and materials scientists.
PDF
