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Background: Chronic wasting disease (CWD) is a fatal transmissible spongiform encephalopathy in cervids. The disease is caused by a pathogenic prion, namely PrP Sc . Currently, diagnosis of CWD relies on IHC detection of PrP Sc in the obex or retropharyngeal lymph nodes (RPLN) or ELISA screening of obex and RPLN followed by IHC confirmation of positive results. In this study, we assessed the performance characteristics of two immunoassays: CWD Ag-ELISA and TeSeE ELISA, RT-QuIC, and MEMS biosensor via testing 30 CWD + and 30 CWD- white-tailed deer RPLN samples., Results: Both CWD Ag-ELISA and TeSeE ELISA correctly identified all CWD + and CWD- samples. A greater intra-assay coefficient of variation (CV) in S/P ratios was observed for the TeSeE ELISA (16.52%), compared to CWD Ag-ELISA (9.49%). However, the high CV did not affect the qualitative results of triplicate assays when the corresponding manufacturer's cutoff was used. The MEMS biosensor not only correctly identified all CWD + and CWD- RPLN samples, but also demonstrated a 100% detection rate for all CWD + samples at dilutions from 10 - 0 to 10 - 3 . Evaluation of RT-QuIC indicated that the rate of false negative reactions decreased from 21.98% at 10 - 2 dilution to 0% at 10 - 4 and 10 - 5 dilutions; and the rate of false positive reactions reduced from 56.42% at 10 - 2 dilution to 8.89% and 2.22% at 10 - 4 and 10 - 5 dilutions, respectively. Based on a stringent threshold of 2 x the first 10 fluorescent readings of each well and a final cutoff of 2/3 positive reactions for each sample, RT-QuIC correctly identified all positive and negative samples at 10 - 4 and 10 - 5 dilutions. Both MEMS biosensor and RT-QuIC achieved 100% sensitivity and 100% specificity under the experimental conditions described in this study., Conclusions: The two immunoassays (CWD Ag-ELISA and TeSeE ELISA) performed comparably on white-tailed deer RPLN samples. MEMS biosensor is a reliable portable tool for CWD diagnosis and RT-QuIC can be used for routine testing of CWD if appropriate testing parameters and interpretive criteria are applied., Competing Interests: Declarations Ethics approval and consent to participate This research did not involve live animals. Retropharyngeal lymph nodes were collected from hunter-harvested dead deer by MDC as part of Misosuri CWD surveillance program. Sample collection and submission protocols were reviewed and approved by MDC Science Committee. Comparative study protocol was approved by the University of Missouri Institutional Biosafety Committee (protocol number: 11721 2.2). Consent for publication Not applicable. Competing interests The authors declare no competing interests., (© 2024. The Author(s).)

The lack of enough diagnostic capacity to detect severe acute respiratory syndrome coronavirus 2 (SARS-COV-2) has been one of the major challenges in the control the 2019 COVID pandemic; this led to significant delay in prompt treatment of COVID-19 patients or accurately estimate disease situation. Current methods for the diagnosis of SARS-COV-2 infection on clinical specimens (e.g. nasal swabs) include polymerase chain reaction (PCR) based methods, such as real-time reverse transcription (rRT) PCR, real-time reverse transcription loop-mediated isothermal amplification (rRT-LAMP), and immunoassay based methods, such as rapid antigen test (RAT). These conventional PCR methods excel in sensitivity and specificity but require a laboratory setting and typically take up to 6 h to obtain the results whereas RAT has a low sensitivity (typically at least 3000 TCID50/ml) although with the results with 15 min. We have developed a robust micro-electro-mechanical system (MEMS) based impedance biosensor fit for rapid and accurate detection of SARS-COV-2 of clinical samples in the field with minimal training. The biosensor consisted of three regions that enabled concentrating, trapping, and sensing the virus present in low quantities with high selectivity and sensitivity in 40 min using an electrode coated with a specific SARS-COV-2 antibody cross-linker mixture. Changes in the impedance value due to the binding of the SARS-COV-2 antigen to the antibody will indicate positive or negative result. The testing results showed that the biosensor's limit of detection (LoD) for detection of inactivated SARS-COV-2 antigen in phosphate buffer saline (PBS) was as low as 50 TCID50/ml. The biosensor specificity was confirmed using the influenza virus while the selectivity was confirmed using influenza polyclonal sera. Overall, the results showed that the biosensor is able to detect SARS-COV-2 in clinical samples (swabs) in 40 min with a sensitivity of 26 TCID50/ml., Competing Interests: Declaration of competing interest The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper., (Copyright © 2023. Published by Elsevier B.V.)

A microfluidic based biosensor was investigated for rapid and simultaneous detection of Salmonella, Legionella, and Escherichia coli O157:H7 in tap water and wastewater. The biosensor consisted of two sets of focusing electrodes connected in parallel and three sets of interdigitated electrodes (IDE) arrays. The electrodes enabled the biosensor to concentrate and detect bacteria at both low and high concentrations. The focusing region was designed with vertical metal sidewall pairs and multiple tilted thin-film finger pairs to generate positive dielectrophoresis (p-DEP) to force the bacteria moving toward the microchannel centerline. As a result, the bacterial pathogens were highly concentrated when they reached the detection electrode arrays. The detection IDE arrays were coated with three different antibodies against the target bacterial pathogens and a cross-linker to enhance the binding of antibodies to the detection electrode. As the binding of bacterial pathogen to its specific antibodies took place, the impedance value changed. The results demonstrated that the biosensors were capable of detecting Salmonella, Legionella, and E. coli 0157:H7 simultaneously with a detection limit of 3 bacterial cells/ml in 30 - 40 min., (Copyright © 2022 Elsevier B.V. All rights reserved.)