Poly-L-lysine functionalized silica membrane-enhanced colorimetric loop-mediated isothermal amplification for...

Traditional detection of foodborne pathogen relies on advanced analyzers, which is inadequate for the rapid control of infections, particularly in resource-limited regions, highlighting the necessity of developing detection systems for point-of-care testing (POCT). Herein, taking Vibrio parahaemolyticus as a detecting target, we reported poly-L-lysine functionalized silica membrane (PL-SM) based loop-mediated isothermal amplification (pLAMP) platform for sensitive on-site detection. This platform utilized PL-SM for DNA capture driven by the electrostatic attraction between protonated amine groups of poly-L-lysine and negatively charged phosphate groups of DNA, followed by introducing a colorimetric indicator calcein for LAMP amplification. After optimization, the colorimetric mode of pLAMP allowed the screening of V. parahaemolyticus with the visual limit of detection (vLOD) of 1 CFU/mL in 50 min, 1000-fold lower than methods based on commercial kits. Validation was performed using 174 seafoods, which was 97 % concordant to those of real-time PCR. Furthermore, an image processing approach was developed based on the analysis of the RGB under UV light. Paired with a smartphone, the objective analytical method could be readily conducted in the field. Thus, we propose a sensitive and visual detection platform, which may play a crucial role in improving testing efficiency and accuracy in food safety, medical diagnostics, and environmental monitoring.