Metal nanoclusters combined with CRISPR-Cas12a for hepatitis B virus DNA detection

Since hepatitis B virus (HBV) infection can cause chronic viral hepatitis, increase the risk of liver fibrosis and cirrhosis, and ultimately result in hepatoma, it is of great significance to explore convenient, rapid, and sensitive diagnostic strategies for HBV DNA detection. In this study, we developed a novel and sensitive fluorescent biosensor for HBV detection based on the sensing system consisting of CRISPR-Cas12a enzymes and metal nanoclusters as the luminescent nanoprobes, involving gold nanoclusters (AuNCs), silver nanoclusters (AgNCs), and copper nanoclusters (CuNCs). The DNA probes could effectively be applied as the template for the preparation of fluorescent metal nanoclusters. In the presence of the HBV target, the trans-cleavage capability of Cas12a was able to be initiated to degrade DNA probes, which brought about the inhibition of metal nanoclusters formation, thereby giving minimal fluorescence signals. In comparison with AuNCs and AgNCs, the CuNCs-based nanosensor exhibited much higher sensitivity. In addition, the fluorescence response of CuNCs to HBV detection was significantly faster, which could be completed within 25 min without the requirements of sophisticated equipment or harsh reaction conditions. Moreover, the practical application of this analysis method was also demonstrated to detect HBV DNA target in human serum samples with satisfactory recovery, which was promising for simple, rapid, sensitive, and label-free HBV DNA bioanalysis .