Photoelectrochemical assay based on CRISPR/Cas12a coupled with AuNP/MoS2/WS2/g-C3N4 nanoprobe for determination of hepatitis B virus

Abstract

A nanoprobe photoelectrochemical (PEC) assay combined with CRISPR/Cas12a was explored to detect nucleic acid. Ternary heterojunctions, nanoflower MoS2/WS2/g-C3N4, were synthesized by hydrothermal method. The narrow band gap materials MoS2, WS2 and the wide band gap material g-C3N4 were composited to obtain ternary heterojunction nanoflowers with high photoelectric response. The gold nanoparticles (AuNPs) in situ grown on MoS2/WS2/g-C3N4 and incubated with signal DNA got PEC nanoprobe, signal DNA/AuNP/MoS2/WS2/g-C3N4. The electrode was modified with electrodeposited AuNPs producing background signal. In the presence of target, catalytic hairpin assembly was activated and target was recycled, and this process activated the activity of the Cas12a enzymes and completed the cleavage. The cleavaged double DNA was linked with capture DNA and nanoprobe, generating PEC signal on AuNPs modified electrode no needing of any electron donor or acceptor. The results showed that the nanoprobe PEC assay to detect target DNA presented a linear detection range from 1 aM to 1 fM with a detection limit of 0.25 aM (S/N = 3). The PEC assay not only presented a high sensitivity and selectivity, but also provided a different pattern for the detection of other nucleic acids.