Enhanced photoelectrochemical aptasensing platform for TXNDC5 gene based on exciton energy transfer between NCQDs and TiO(2) nanorods

The over expression of thioredoxin domain-containing protein 5 (TXNDC5) can promote the growth of castration-resistant prostate cancer (CRPC). A novel highly sensitive photoelectrochemical (PEC) aptsensor was developed for the detection of TXNDC5 by using the nanohybrids (TiO(2) NRs/NCQDs) of nitrogen-doped carbon quantum dots (NCQDs) and TiO(2) nanorods as the photo-to-electron conversion medium. TiO(2) NRs/NCQDs nanohybrids were prepared by controlling the experimental condition. TiO(2) NRs were self-assembled to form the nanopores with good photocurrent conversion efficiency. NCQDs possessed carboxyl groups (−COOH) and amino groups (−NH(2)) in the preparation process. −COOH and −NH(2) groups played important roles for anchoring the capture probes (5′ primer and 3′ primer) through covalent binding. The ultrasensitive and stable detection for TXNDC5 was achieved by the specific recognition between the capture probes and the targets. The fabricated aptsensor showed excellent performance with a wide linear range (0.5 fmol/L ∼ 10 nmol/L) and a low detection limit of 0.1 fmol/L. This kind of aptsensor would provide a potential application for TXNDC5.