Herein, based on CRISPR/Cas12a and catalytic hairpin assembly (CHA) non-enzyme amplification technology, a general photoelectrochemical (PEC) biosensor with high sensitivity and specificity is constructed using Bi/g-C₃N₄ nanohybrids as photoelectric composite electrode for the detection of miRNA-122. Notably, the single-strand DNA labelled with the sensitizer methylene blue (MB) was combined with the electrode to secondary improved the photocurrent response and effectively reduced the detection background. The miRNA-122 was specifically recognized by the CHA process, and then amplified into a rich signal output, which effectively improved the detection sensitivity. The target DNA complex generated by CHA cycle on the electrode surface hybridized with Cas12a-crRNA duplex to formed the Cas12a-crRNA-target DNA ternary complex, which activated their trans-cleavage ability and repelled MB to leave the electrode surface. The PEC signal was significantly reduced, achieving accurate detection of the miRNA-122. Under the action of multiple amplification mechanisms, the sensor showed prominent sensitivity and selectivity, the universal CRISPR/Cas12a cutting characteristics further expanded its analysis potential and simplified the operation difficulty, which can expand the application in biomedical detection and clinical diagnosis, showing great potential in efficient nucleic acid detection and in vitro diagnosis.

在此，基于CRISPR/Cas12a和催化发夹组装（CHA）非酶扩增技术，利用Bi/gC ₃ N _{4构建了一种具有高灵敏度和特异性的通用光电化学（PEC）生物传感器。}纳米杂化物作为光电复合电极检测miRNA-122。值得注意的是，用敏化剂亚甲蓝（MB）标记的单链DNA与电极结合，二次提高了光电流响应，有效降低了检测背景。miRNA-122被CHA过程特异性识别，然后放大成丰富的信号输出，有效提高了检测灵敏度。CHA循环在电极表面产生的靶DNA复合物与Cas12a-crRNA双链体杂交形成Cas12a-crRNA-靶DNA三元复合物，激活它们的反式切割能力，排斥MB离开电极表面。PEC信号显着降低，实现了对miRNA-122的准确检测。在多重放大机制的作用下，