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Development and deployment of biosensors for the rapid detection of the 2019 novel severe acute respiratory syndrome—coronavirus 2 (SARS-CoV-2) are of utmost importance and urgency during this recent outbreak of coronavirus pneumonia (COVID-19) caused by SARS-CoV-2 infection, which spread rapidly around the world. Cases now confirmed in February 2022 indicate that more than 170 countries worldwide are affected. Recent evidence indicates over 430 million confirmed cases with over 5.92 million deaths scattered across the globe, with the United States having more than 78 million confirmed cases and over 920,000 deaths. The US now has many more cases than in China where coronavirus cases were first reported in late December 2019. During the initial outbreak in China, many leaders did not anticipate it could reach the whole world, spreading to many countries and posing severe threats to global health. The objective of this review is to summarize the origin of COVID-19, its biological nature, comparison with other coronaviruses, symptoms, prevention, treatment, potential, available methods for SARS-CoV-2 detection, and post-COVID-19 symptoms.

This paper presents an impedance-based biosensor for rapid and simultaneous detection of Salmonella serotypes B, D, and E with very low concentration. The biosensor consists of a focusing region, and three detection regions. The cells focusing was achieved using a ramp down electroplated vertical electrode pair along with tilted thin film finger pairs that generate p-DEP forces to focus and concentrate the bacterial cells into the center of the microchannel, and direct them toward the detection region. The detection regions consist of three interdigitated electrode arrays (IDEA), each with 20 pairs of finger coated with a mixture of anti-Salmonella antibody and crosslinker to enhance the adhesion to IDEA. The impedance changes as the target Salmonella binds to the antibody. The biosensor has showed excellent performance as proven by the detection of a single Salmonella serotype B, and simultaneous detection of two Salmonella serotypes B and D with a limit of detection (LOD) of 8 Cells/ml in ready-to-eat turkey samples, the addition of focusing capability improved the measured signal by a factor of between 4–4.5, the total detection time of 45 minutes, selectivity of the sensor on different types of bacterial cells, and the ability to distinguish between dead and live cells.

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Developing rapid and sensitive methods for the detection of pathogenic Escherichia coli O157:H7 remains a major challenge in food safety. The present study attempts to develop an immunofluorescence technique that uses Protein-A-coated, magnetic beads as the platform. The immunofluorescence technique described here is a direct detection method in which E. coli O157:H7 cells are labeled with tetramethylrhodamine (TRITC) fluorescent dye. TRITC-labeled bacteria are captured by the desired antibody (Ab), which is immobilized on the Protein-A magnetic beads. Fluorescence of the captured cells is recorded in a fluorescence spectrophotometer, where the fluorescence values are shown to be directly proportional to the number of bacteria captured on the immunobead. The formation of an immunocomplex is evidenced by the fluorescence of the beads under microscopy. The Ab immobilization procedure is also evidenced by microscopy using fluorescein isothiocyanate (FITC)-labeled Ab. The total experimental time, including preparation of the sample, is just 1h. The minimum bacterial concentration detected by this method is 1.2±0.06×10(3)CFUml(-1). The high specificity of this method was proved by using the specific monoclonal Ab (MAb) in the test. The proposed protocol was successfully validated with E. coli O157:H7-infected meat samples. This approach also opens the door for the detection of other bacterial pathogens using Protein-A magnetic beads as a detection platform.