CRISPR-Cas-Mediated Ultrasensitive Detection of Viral Nucleic Acids via Singlet Oxygen-Activated Chemiluminescence

Herein, we report a novel clustered regularly interspaced short palindromic repeats (CRISPR)/Cas-mediated chemiluminescence assay (CRISPR-Cas-CLA) for the ultrasensitive detection of viral nucleic acids of HPV18 and HPV16. The CRISPR-Cas-CLA comprises a CRISPR/Cas12a system that specifically recognizes the target nucleic acid, a signal-conducting nanoconjugate (MB-ssDNA-PSNP) formed by coupling singlet-oxygen (¹O₂)-generating photosensitive nanoparticles (PSNPs) to magnetic beads (MBs) via a single-stranded DNA (ssDNA) linker, and ¹O₂-activated chemiluminescence nanoparticles (CLNPs). In the presence of the target nucleic acid, the ssDNA linker of the nanoconjugate is cleaved by the target-activated CRISPR/Cas12a system, and the PSNPs are dissociated from the MBs. The PSNP-containing supernatant obtained by magnetic separation is added to the CLNP-coated detection plate. Upon light irradiation of the CLNP-PSNP mixture in the well, strong chemiluminescence is generated with the subsequent addition of hydrogen peroxide, enabling the detection of the target nucleic acids. The proposed CRISPR-Cas-CLA system offers ultrahigh sensitivity (∼1.04 aM), simple operation, and low cost, providing a new direction for the development of PCR-free detection strategies for ultralow abundance nucleic acids.