Development of Nanobody-Displayed Whole-Cell Biosensors for the Colorimetric Detection of SARS-CoV-2.

The accurate and effective detection of severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is essential to preventing the spread of infectious diseases and ensuring human health. Herein, a nanobody-displayed whole-cell biosensor was developed for colorimetric detection of SARS-CoV-2 spike proteins. Serving as bioreceptors, yeast surfaces were genetically engineered to display SARS-CoV-2 binding of llama-derived single-domain antibodies (nanobodies) with high capture efficiency, facilitating the concentration and purification of SARS-CoV-2. Gold nanoparticles (AuNPs) employed as signal transductions were functionalized with horseradish peroxidase (HRP) and anti-SARS monoclonal antibodies to enhance the detection sensitivity. In the presence of SARS-CoV-2 spike proteins, the sandwiched binding will be formed by linking engineered yeast, SARS-CoV-2 spike proteins, and reporter AuNPs. The colorimetric signal was generated by the enzymatic reaction of HRP and its corresponding colorimetric substrate/chromogen system. At the optimal conditions, the developed whole-cell biosensor enables the sensitive detection of SARS-CoV-2 spike proteins in a linear range from 0.01 to 1 µg/mL with a limit of detection (LOD) of 0.037 µg/mL (about 4 × 108 virion particles/mL). Furthermore, the whole-cell biosensor was demonstrated to detect the spike protein of different SARS-CoV-2 variants in human serum, providing new possibilities for the detection of future SARS-CoV-2 variants.

Stereotype Knowledge and Endorsement in Schizophrenia.

BACKGROUND: Social cognition is severely impaired in schizophrenia. Emotion processing, attributional biases, and theory of mind are often impaired, as well as the understanding of shared social knowledge. So far, little is known about stereotype knowledge and endorsement in schizophrenia. SAMPLING AND METHODS: White patients with schizophrenia and matched healthy respondents reported both their personal beliefs and the predicted beliefs of other people toward Black (study 1) and Gypsy individuals (study 2). RESULTS: Results showed that respondents in the clinical sample displayed less stereotype endorsement as compared to the matched healthy respondents. Most importantly, the contents of the responses provided by the 2 samples were strongly overlapped. CONCLUSIONS: Findings indicate that individuals with schizophrenia tend to hold less negative attitudes toward stigmatized outgroups and, most notably, that knowledge about culturally transmitted stereotypes is relatively preserved in schizophrenia. Future research should address the generalizability of the findings in relation to the perception of other stigmatized social groups.