A novel enhanced photoelectrochemical DNA sensor, based on a TiO₂/Au hybrid electrode structure, was developed to detect target DNA. The sensor was developed by successively modifying fluorine-tin oxide (FTO) electrodes with TiO₂ nanoparticles, gold (Au) nanoparticles, hairpin DNA (DNA1), and CdSe-COOH quantum dots (QDs), which acted as signal amplification factors. In the absence of target DNA, the incubated DNA1 hairpin and the CdSe-COOH QDs were in close contact with the TiO₂/Au electrode surface, leading to an enhanced photocurrent intensity due to the sensitization effect. After incubation of the modified electrode with the target DNA, the hairpin DNA changed into a double helix structure, and the CdSe QDs moved away from the TiO₂/Au electrode surface, leading to a decreased sensitization effect and photoelectrochemical signal intensity. This novel DNA sensor exhibited stable, sensitive and reproducible detection of DNA from 0.1 μM to 10 fM, with a lower detection limit of 3 fM. It provided good specificity, reproducibility, stability and is a promising strategy for the detection of a variety of other DNA targets, for early clinical diagnosis of various diseases.

基于TiO ₂ / Au杂化电极结构的新型增强型光电化学DNA传感器被开发用于检测目标DNA。该传感器是通过依次用TiO ₂纳米颗粒，金（Au）纳米颗粒，发夹DNA（DNA1）和CdSe-COOH量子点（QDs）修饰氟氧化锡（FTO）电极而开发的，CdSe-COOH量子点用作信号放大因子。在没有目标DNA的情况下，孵育的DNA1发夹和CdSe-COOH QD与TiO ₂ / Au电极表面紧密接触，由于敏化效应，导致光电流强度增强。将修饰的电极与目标DNA孵育后，发夹DNA变为双螺旋结构，CdSe QD从TiO ₂移开/ Au电极表面，导致敏化效果和光电化学信号强度降低。这种新型的DNA传感器可对0.1μM至10 fM的DNA进行稳定，灵敏和可重现的检测，检测限较低，为3 fM。它提供了良好的特异性，可重复性，稳定性，是用于检测多种其他DNA靶标，用于各种疾病的早期临床诊断的有前途的策略。