A practical colorimetric assay was developed for the detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). For this purpose, magnetic γ Fe 2 O 3 nanoparticles were synthesized and used as a peroxidase-like mimic activity molecule. In the presence of γ Fe 2 O 3 nanoparticles, the color change of H 2 O 2 included 3,3′,5,5′-tetramethylbenzidine was monitored at the wavelength of 654 nm when spike protein interacted with angiotensin-converting enzyme 2 receptor. This oxidation-reduction reaction was examined both spectroscopically and by using electrochemical techniques. The experimental parameters were optimized and the analytical characteristics investigated. The developed assay was applied to real SARS-CoV-2 samples, and very good results that were in accordance with the real time polymerase chain reaction were obtained.

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The need for practical detection of folic acid (FA) has been increased day by day. For this reason in this work, a two steps electroanalytical technique, centri‐voltammetry was utilized for FA detection for the first time. In order to get rid of the slow electrode kinetics of FA oxidation, the working electrode was modified with graphene‐Pt hibrid nanomaterial. Also for increasing the sensitivity, 1‐Chloro‐2‐[2‐(2‐methoxyethoxy) ethoxy]ethane (TEG−Cl) and 1,2‐di{2‐[2‐(2‐methoxyethoxy)ethoxy] ethoxy}‐4‐nitrobenzene (4NC−NO2) was used as a carrier material. After the characterization of graphene‐Pt hybrid nanomaterial, experimental parameters like, 4NC−NO2 amount, adsorption time, centri‐voltammetric parameters like centrifuge time and speed were optimized. After that, analytical characteristics such as linear range, relative standard deviation (R.S.D), limit of detection (LOD) and limit of quantification (LOQ) values were found. In this manner, linear range was obtained for FA between 1.0 μM–1000 μM with the equations of y=0.0108x+1.0459 (R2=0.9977). R.S.D value was calculated for 0.83 mM FA (n=3) as 1.86 % while LOD and LOQ values were found as 1.00 μM and 3.34 μM respectively. After the examination of interference effect of substances like ascorbic acid and uric acid, established centri‐voltammetric technique was enforced for FA detection in pharmateutical tablets. As a result, the recovery value was calculated as 96.4 %.

A Pseudomonas fragi (P.fragi) and Graphene-gold hybrid nanomaterial included carbon felt electrode (Graphene-Au/CFE) bioanode was developed and optimized. Then this bioanode was combined with a platinum cathode and a single...

In this work, Lactococcus lactis subsp. lactis DLP27 (L .lactis) strain isolated from a traditional Turkish raw milk cheese, Divle Obruk Cheese, was used as a biocatalyst on the bioanode combined with a platinum cathode to fabricate a Nafion membrane based double compartment microbial fuel cell (MFC). Graphene‐gold‐platinum hybrid nanomaterial was used as modifier in L. lactis immobilized carbon felt based bioanode. Developed Nafion membrane based double compartment MFC characteristics were inspected by using optimized bioanode. In consequence, an open‐circuit voltage of 0.282 V, a maximum current density of 59.52 μA/cm2 and a maximum power density of 2.12 μW/cm2 were achieved with excellent lifetime of 49 days with developed MFC system.