Nanozyme-based dual-mode DNA biosensor for self-powered ultrasensitive detection of sulfate-reducing bacteria

Sulfate-reducing bacteria (SRB) are recognized as significant contributors to microbiologically induced corrosion (MIC). Developing effective, economical, sensitive, and specific detection methods for SRB is crucial for understanding microbial corrosion mechanisms and for early monitoring. In this study, a novel dual-mode DNA biosensor was developed, utilizing a nanozyme-based fuel cell to enable self-powered detection of the DsrA gene in SRB, while demonstrating excellent sensitivity, specificity, and reliability. The open circuit voltage (E^OCV) and RGB Blue values were employed as the signal response for the electrochemical and colorimetric modes, respectively. Under optimized conditions, the detection limits of the proposed biosensor were determined to be 0.33 fM in the electrochemical mode and 0.41 fM in the colorimetric mode. Additionally, the biosensor was utilized to detect the SRB DsrA gene fragments isolated and extracted from real samples. Compared to previously reported techniques, the biosensor demonstrated a relatively wide detection range and a low detection limit, providing a new approach for the sensitive detection of corrosion microorganisms, with substantial application potential.