A highly sensitive and selective photoelectrochemical aptasensor for Kanamycin based on a self–supported TiO2/Au nanowires arrays electrode

Kanamycin is an antibiotic commonly used for the prevention and treatment of infections. The monitoring of kanamycin is of vital significance for maintaining food safety and safeguarding public health. However, the sensitive and reliable detection of kanamycin under visible light irradiation still presents significant challenges. In this study, a self–supported electrode was fabricated from a titanium dioxide nanowire array modified with gold nanoparticles, utilizing a straightforward and controllable electrochemical deposition method. The synthesized photoanode exhibited enhanced photoelectrochemical performance under visible light, which can be attributed to the localized surface plasmon resonance effect of Au nanoparticles. Kanamycin aptamers served as recognition elements, immobilized on the TiO₂/Au nanowires through Au S bonds. The specific recognition and high affinity between the aptamers and kanamycin contributed to the excellent sensitivity of the photoelectrochemical aptasensor. The sensor demonstrated a linear range of 1–500 nM, with a limit of detection as low as 0.42 nM (S/N = 3). Furthermore, the sensor exhibited remarkable anti–interference capability in the presence of other contaminants and maintained excellent stability. It has been successfully applied for the analysis of kanamycin in real milk samples. The simple, efficient, highly sensitive, selective, and reproducible detection platform for kanamycin developed in this study offers significant potential for a wide range of applications.