Synergistic integration of MoOx co-catalyst with oxygen vacancies-engineered on BiVO4 for enhancing the sensitivity of DNA

Photoelectrochemical (PEC) biosensors of deoxyribonucleic acid (DNA) hybridization with simultaneously high signal-to-noise ratio and low limit-of-detection remains greatly challenging owing to the rapid recombination of photogenerated carriers of photoelectrode. Herein, we report an efficient strategy to amplify the photocurrent signal by coupling the MoOx co-catalysts and surface oxygen vacancies (Ov) of BiVO4 as photoelectrode (MoOx/ BiVO4-Ov). Using a simple in situ solution impregnation method, non-noble metal MoOx nanoparticles can be grown uniformly onto BiVO4, subsequently, abundant surface Ov of MoOx/BiVO4 is induced by N2-plasma treatment. The coupling of MoOx and surface Ov on BiVO4 can efficiently promote the separation of photo-generated carriers, as a result, the optimized MoOx/BiVO4-Ov shows an excellent photocurrent response of 300.52 mu A/cm2 under simulated sunlight illumination, which is 59.6 and 5.4 times higher than that of pristine BiVO4 and MoOx/BiVO4, respectively. Furthermore, the PEC biosensor based on MoOx/BiVO4-Ov demonstrates an excellent sensitivity toward DNA hybridization (10 pM to 10 mu M) with a calculated detection limit down to 0.0549 pM. Moreover, this PEC biosensor exhibits specific selectivity as well as high stability. The proposed amplification strategy by the synergistic effect of co-catalysts and defects is valuable for the construction of efficient sensors for the early diagnosis of multiple diseases.