A “turn-on” photoelectrochemical DNA biosensor based on charge transfer between BiVO4 and gold nanoparticles

An enhanced charge transfer between BiVO 4 and Au nanoparticles (AuNPs) was utilized to design a “turn-on” photoelectrochemical (PEC) biosensor for sensitive detection of target DNA. The calcination of BiVO 4 on indium tin oxide (ITO) substrate was integrated with Au nanoparticles (NPs) labelled probe DNA (pDNA-AuNPs) as photoelectrode (ITO/BiVO 4 /pDNA-AuNPs). The cathodic photocurrent increased due to the coupling BiVO 4 with AuNPs, which acted as the blank signal of this PEC platform. The probe specifically recognized and captured the target DNA (tDNA) to form double strain DNA (dsDNA) after hybridization. The photocurrent intensity of the ITO/BiVO 4 /dsDNA-AuNPs photoelectrode further increased due to the enhancement of the charge transfer between BiVO 4 and AuNPs through dsDNA chain. This photocurrent enhancement was linear proportional to the logarithm of tDNA concentration. Based on this strategy, the PEC assay displayed a linear range from 1 aM to 10 pM and the detection limit was as low as 0.2 aM (S/N = 3). It provides a promising platform for ultrasensitive target DNA detection, and thus shows a great potential in genetic disease or cancer diagnostics and infectious pathogen detection.