Rapid visual detection of Treponema pallidum using the RPA-CRISPR/Cas12a system.

Syphilis, caused by Treponema pallidum, is a sexually transmitted infection that has re-emerged globally over the past decade, posing significant public health challenges. Conventional diagnostic methods are limited by lengthy processing times, operational complexity, and moderate sensitivity, highlighting the urgent need for rapid, sensitive, and user-friendly detection strategies. In this study, we developed a visual detection platform for T. pallidum DNA by integrating recombinase polymerase amplification (RPA) with CRISPR/Cas12a technology. The assay can be completed within one hour, with results directly interpreted via fluorescence readout. It demonstrated a detection limit as low as 11.34 copies/µL and high specificity, accurately distinguishing T. pallidum without cross-reactivity with common blood-borne pathogens, including HIV, HBV, HCV, and DENV. The clinical sample verification showed a consistency rate of 96.6% with the actual diagnosis. To enhance suitability for point-of-care applications, the RPA-CRISPR/Cas12a system was further adapted to a lateral flow assay (LFA) format, achieving a detection sensitivity of 5.56 × 10² copies/µL while minimizing reliance on specialized instrumentation. Overall, this platform provides a rapid, sensitive, and robust approach for point-of-care syphilis diagnosis and offers a reference framework for detecting other pathogenic organisms.