Single-step duplex CRISPR coupled with lateral flow assay for point-of-care detection of human immunodeficiency virus and Treponema pallidum

Abstract

Continued acquired immunodeficiency syndrome (AIDS) caused by the human immunodeficiency virus (HIV) and syphilis caused by Treponema pallidum (TP) pose great challenges for global health, highlighting the need for rapid and sensitive diagnostics. Here, we introduced DIAL (Duplex Integrated All-in-one CRISPR Lateral flow assay), a simplified CRISPR-based diagnostic system for simultaneous detection of HIV and TP. We developed a single-step duplex CRISPR assay for dual-target recognition, which incorporated reverse transcription, multiplex recombinase polymerase amplification, transcription, CRISPR/Cas12a detection, and CRISPR/Cas13a detection in one pot. Then, we combined CRISPR detection assay with a “line-elimination” dual-line lateral flow assay for low-cost and equipment-free visual readout. We further developed reagent lyophilization and extraction-free sample lysis techniques to meet the point-of-care testing. The optimized DIAL system detected as low as 100 copies per µL of both HIV RNA and TP DNA within 45 minutes. In a clinical evaluation of 46 samples, it demonstrated 100% sensitivity and 97.5% specificity for HIV and 90% sensitivity and 100% specificity for TP, relative to quantitative PCR. The DIAL provided a scalable, accessible approach for decentralized screening of sexually transmitted infections or other pathogens in resource-limited settings.