Oxygen vacancy-amplified photoelectrochemical sensing of 8-oxo-guanine DNA glycosylase using Bi6S2O15 nanowires.

8-Oxo-guanine DNA glycosylase (OGG) repairs oxidatively damaged DNA and correlates with various diseases, and sensitive OGG detection is vital for clinical diagnosis. Traditional detection methods have inherent drawbacks, including radiation risk and complicated preparation. Herein, a new photoelectrochemical (PEC) biosensor based on hydrothermally synthesized Bi6S2O15 nanowires was fabricated for OGG quantification via dopamine (DA)-activated cathodic photocurrent amplification. Specifically, OGG specifically cleaved 8-oxoG-containing hairpin DNA to release the DA aptamer, which was degraded by Exo I. The liberated DA coordinates with Bi6S2O15 to produce surface oxygen vacancies (Ov). The formed Ov suppresses photocarrier recombination and elevates photocurrent. In the absence of OGG, intact hairpin DNA captures DA and weakens photocurrent. This assay achieves good linearity between photocurrent change and logarithmic OGG concentration with a limit of detection of 1.4 × 10-3 U/mL. It possesses excellent selectivity and stability, and desirable recoveries in human serum samples. This work provides a simple PEC platform for OGG testing and broadens the application of bismuth oxysulfide in biosensing.