A novel photoelectrochemical biosensor for sensitive detection of nucleic acids based on recombinase polymerase...

Nucleic acids detection is essential for diagnosing pathogens; however, traditional methods usually face challenges such as low sensitivity, lengthy reaction times, and strict temperature requirements. This study develops a novel photoelectrochemical (PEC) biosensor that integrates recombinase polymerase amplification (RPA) with a 3D-array titania (TiO₂) nanorods nanorod electrode, addressing the challenge of achieving sensitive detection of RPA-amplified nucleic acids products, thereby enabling earlier and more reliable pathogen detection. The biosensor utilizes a triple-binding mode involving FITC antibodies, target nucleic acids, and an HRP-streptavidin sandwich structure, significantly improving the bio-functionalization of the electrode surface. The isothermal RPA process amplifies DNA at 37 °C within 20 min, while the TiO₂ nanorods ensure efficient photoelectric conversion. The oxidation of 4-chloro-1-naphthol (4-CN) generates a signal-reducing benzo-4-chlorohexadienone (4-CD), enabling precise and sensitive detection. This PEC-RPA biosensor successfully detects Orientia tsutsugamushi (Ot) nucleic acids with a detection limit of 15 copies/μL within 60 min, demonstrating robust performance. The study provides a promising strategy for advancing pathogen nucleic acids diagnostic platforms and offers a versatile approach adaptable for detecting diverse pathogens.