ZnCuInSe/Au/TiO2 sandwich nanowires-based photoelectrochemical biosensor for ultrasensitive detection of kanamycin

Highlights: • ZnCuInSe quantum dots was used for the first time to constructed the ZnCuInSe/Au/TiO₂ sandwich nanowires photoelectrode. • Au NPs serve as photosensitizer and electron relay facilitating light to electron conversion and charge transfer. • The PEC sensor for the detection of kanamycin was developed using ZnCuInSe/Au/TiO₂ as substrate with a LOD down to 0.2 nM. • ZnCuInSe/Au/TiO₂ nanowires can detectionof different biomolecules by modifying various recognizers. A highly selective and sensitive photoelectrochemical (PEC) sensing platform was developed for kanamycin assay based on the aptamer modified sandwich-structured ZnCuInSe/Au/TiO₂ nanowires. Sandwiched between the TiO₂ nanowires and the ZnCuInSe quantum dot (QDs) layer, the Au nanoparticles (Au NPs) serves as a plasmonic photosensitizer and an electron relay, which expand the light absorption range and facilitates the charge transfer. Also, ZnCuInSe QDs, a broad spectrum photosensitizer can capture visible light, which enhance the photocurrent density response. Through the Au–S bond and Cu–S bond, the HS-aptamer were immobilized on the ZnCuInSe/Au/TiO₂ nanowires as a recognition unit for kanamycin. The proposed sensing platform showed excellent assay performance for kanamycin with a linear response range from 0.2 to 250 nM, and high selectivity. By changing the recognizers, the proposed sensing platform could be easily extended to detect other biomolecules, and may have a promising application in bioanalysis.