A CRISPR/Cas12a-based fluorescence aptasensor for the rapid and sensitive detection of ampicillin.

This study introduces CRISPR/Cas-based aptasensor for the highly sensitive and specific detection of the antibiotic, ampicillin. Ampicillin (AMPI) is a commonly used antibiotic for treating pathogenic bacteria and is additionally added to livestock feed in agriculture. This study can enable early detection of antibiotic residues, prevent their accumulation in the environment, and ensure compliance with food safety regulations. Herein, the aptasensor was developed with the CRISPR/Cas system by utilizing three different ampicillin-specific aptamers, each conjugated with a biotin at the 5'-end. The ssDNA activator was bound to the aptamers through complementary base pairings. The attraction of the aptamers to the ampicillin target released the bound ssDNA, causing the activation of the CRISPR/Cas system. The DNA reporter probe, labelled with Cy3 and a quencher, turns on the fluorescence signal when cleaved by the activated Cas12a through trans-cleavage measured using a fluorescence spectrophotometer at 590 nm. The fluorescence signal was linearly proportional to the ampicillin target concentration with a 0.01 nM limit of detection and a read-out time of 30 min. This aptasensor showed high sensitivity towards ampicillin even in the presence of other antibiotics. The method was also successfully implemented for ampicillin detection in spiked food samples.

Virtual non-technical skills assessment training is an effective, scalable approach for novice raters.

OBJECTIVES: The COVID-19 pandemic has forced a creative transition to virtual platforms due to physical distancing and travel restrictions. We designed and tested a highly scalable virtual training curriculum for novice raters using the Oxford NOTECHS non-technical skills rating system. DESIGN: A three-day training course comprising virtual didactics, virtually facilitated simulations, and independent live observations was implemented. NOTECHS scores were submitted for eleven standardized video simulations and four live operations. Intraclass correlation coefficients (ICCs) were calculated for total NOTECHS scores and subcomponent scores. Raters previously trained in-person with the same standardized videos served as a comparator group for equivalence testing. SETTING: All study activities were conducted in a large academic tertiary referral center in Singapore as part of an ongoing surgical safety initiative. PARTICIPANTS: Seven staff members underwent training (three virtually and four in-person).  None had prior surgical experience or non-technical skills assessment training. RESULTS: ICCs for total NOTECHS scores were 0.85 (95% CI, 0.73-0.98) for virtually trained raters and 0.83 for those trained in-person (95% CI, 0.68-0.99).  Scores were equivalent between groups within a 10% margin. CONCLUSIONS: Non-technical skills assessment can be reliably taught in a highly scalable virtual format. Virtual NOTECHS training is a valuable tool for educational and quality improvement initiatives during the COVID-19 pandemic and for centers that lack ready access to onsite non-technical skills training expertise.