A Rapid and Ultrasensitive Detection of Coxsackievirus A16 Using Reverse Transcription Multiple Cross Displacement Amplification Combined with the CRISPR-Cas12a-Based Biosensing System.

Coxsackievirus A16 (CVA16) is one of the primary viral etiological agents of hand, foot, and mouth disease (HFMD) in infants and children under five years of age. Prompt and reliable detection of CVA16 is crucial for guiding immediate therapeutic interventions and for implementing effective epidemic prevention and control strategies, particularly in settings with limited resources. Herein, a diagnostic platform for CVA16 (CVA16-RT-MCDA-CRISPR) was developed by combining reverse transcription multiple cross displacement amplification (RT-MCDA) with CRISPR-Cas12a-based detection. In this system, the CVA16 VP1 gene was preamplified using RT-MCDA technology. The resulting amplicons were then specifically recognized and cleaved by the CRISPR-Cas12a-based detection system. MCDA primers, an engineered CP1 primer, and a specific guide RNA (gRNA) were designed to target the VP1 gene of CVA16. The assay achieved a limit of detection of 2.8 × 10-1 copies per microliter for CVA16 RNA standard templates and showed no cross-reactivity against non-CVA16 pathogens. Furthermore, the CVA16-RT-MCDA-CRISPR assay's feasibility was validated using 96 clinical samples. Taken together, these results demonstrate that the CVA16-RT-MCDA-CRISPR assay is a reliable diagnostic tool for rapidly and sensitively detecting CVA16.