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Norovirus is one of the main pathogens causing acute gastroenteritis worldwide, and possesses rich genetic diversity. We established a simple, fast, and suitable colloidal gold immunochromatographic detection method for common epidemic strains of Norovirus. A pair of monoclonal antibodies that are sensitive to recognizing Norovirus was successfully screened and used as gold-labeled antibody and capture antibody, respectively. The assembly conditions of the test strip were optimized to determine the labeling pH, the concentration of capture antibody and concentration of AuNP-labeled antibody, then the performance of the strips, including sensitivity testing and specificity testing, was evaluated. The minimum detection concentration of the established Norovirus colloidal gold test strip detection method is 10 ng mL−1. This antibody has no cross-reactivity with HCoV-NL63, HCoV-OC43, Influenza A (H1N1), Influenza A (H9N2), respiratory syncytial virus or Varicella zoster virus. The established colloidal gold detection method was used to analyze 11 fecal samples, and the results showed that only two samples were positive and the rest were negative, in agreement with the RT-PCR result. The whole colloidal gold test strip detection method process took 15 min, and could be used for on-site detection. The established colloidal gold test strip detection method has good specificity and stability, and can be used for the detection of common Norovirus strains and in large-scale epidemiological investigations. [ABSTRACT FROM AUTHOR]

Valproic acid (VPA) is mainly used in the clinic to treat epilepsy, for which the therapeutic window is narrow to avoid causing adverse reactions such as hepatotoxicity and teratogenicity. Therefore, timely therapeutic drug monitoring is needed. A hapten containing a benzene ring and an amino group was designed and used to screen a monoclonal antibody (mAb) 3G10 with high specificity and sensitivity. The IC50 value of mAb 3G10 was ascertained as 68.13 ng mL−1 through an indirect competitive enzyme-linked immunosorbent assay. A colloidal gold-based immunochromatographic strip (CG-ICS) for the detection of free VPA in human serum was developed with gold-labeled mAb 3G10. Qualitative analysis of human serum samples can be conducted through visual observation. The visual limit of detection (vLOD) was 2 μg mL−1, and the cut-off value was 100 μg mL−1. A standard curve for quantitative detection was generated using a portable scanner, with a calculated LOD (cLOD) value of 0.144 μg mL−1 and a linear range of 0.565–48.385 μg mL−1. Comparing the results of CG-ICS for actual positive samples with those of a direct chemiluminescence kit, there was a good correlation between the two methods. Therefore, our CG-ICS can be applied to the rapid clinical monitoring of free VPA. [ABSTRACT FROM AUTHOR]