Poly-L-lysine functionalized silica membrane-enhanced colorimetric loop-mediated isothermal amplification for sensitive and rapid detection of Vibrio parahaemolyticus

Abstract

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.