Homogeneous electrochemical sensor for sensitive detection of HBV DNA based on magnetic separation and CRISPR/Cas12a protein trans-cleavage.

Infection with hepatitis B virus (HBV) represents a major challenge to global health, especially in areas of inadequate healthcare infrastructure, rapid and on-site detection plays a crucial role in effective disease management and control. Consequently, it is necessary to develop some simple but sensitive HBV screening techniques. In this work, a homogeneous electrochemical biosensor was constructed for sensitive and specific HBV DNA detection through the integration of CRISPR/Cas12a target recognition and magnetic bead-based separation. The sensor exploits the collateral cleavage activity of CRISPR/Cas12a protein upon recognition of target double-stranded DNA, enabling the degradation of methylene blue-labeled single-stranded DNA captured on magnetic beads (MBs). Then the MBs are separated and redissolved in the solution and the electrochemical response of the system can be tested in homogeneous solution. The electrochemical signal has relationship with the concentration of HBV DNA within a range of 10 fM - 10 nM, and the LOD is 3.74 fM. The sensor demonstrates excellent selectivity and biological stability, which has potential application in clinical diagnosis, especially in resource-limited environments.