Self-powered photoelectrochemical aptasensor based on MIL-68(In) derived InO hollow nanotubes and Ag doped ZnInS quantum dots for oxytetracycline detection.

A self-powered photoelectrochemical (PEC) aptasensor was constructed based on MIL-68(In) derived indium oxide hollow nanotubes (InO HNs) and Ag-doped ZnInS quantum dots (QDs) as sensing matrix for the ultrasensitive detection of oxytetracycline (OTC). The hollow tube structure of the designed photoelectric active platform provided abundant active sites and a larger specific surface area for the immobilization of target recognition unit. The coupling of Ag:ZnInS QDs and InO HNs can accelerate the transmit and separation of photoinduced charge, and thus greatly increasing the intensity of photocurrent signal. Then, the well-constructed OTC-aptamer was anchored on the modified photoelectrode as an accurate capturing element, achieving the specific detection of analyte. Under optimal conditions, the photocurrent intensity of the PEC aptasensor decreases linearly, with a linear response range of 10 -10 nmol/L, and a limit of detection (LOD) of 3.3 × 10 nmol/L (S/N = 3). The developed self-powered aptasensor with excellent reproducibility, stability, and selectivity, provides a potential way to detect antibiotic residues in environmental media.