Amplification-free detection of HBV DNA mediated by CRISPR-Cas12a using surface-enhanced Raman spectroscopy.

Nucleic acid markers have been widely used in the detection of various virus-related diseases, including hepatitis B virus (HBV), which is spreading worldwide. The trans-activated CRISPR-Cas system has shown excellent sensitivity and specificity in nucleic acid detection. However, nucleic acid testing usually requires amplification of the target nucleic acid for more accurate and specific detection; furthermore, current nucleic acid assays are time-consuming, costly, and are limited by non-specific cross-reactivity. We developed an amplification-free viral DNA biosensor-based diagnostic method that uses a clustered regularly interspaced short palindromic repeats-associated system (CRISPR/Cas)-based approach with surface enhanced Raman spectroscopy. This method can specifically identify the target site by changing the crRNA sequence. In addition, the incubation period and development of the disease can be determined by quantitative detection of viral DNA. This system could achieve rapid and highly sensitive detection of HBV DNA within 50 min and vast detection range from 0.1 pM to 1 nM. Therefore, a combined CRISPR/Cas12a-SERS-based assay would improve the sensitivity of detection in assays using multiple biomarkers. In conclusion, our CRISPR/Cas12a-based biosensor would enable rapid, simple, and sensitive detection of HBV nucleic acids.