Piwi-interacting RNAs (piRNAs) are a class of noncoding small RNAs that have been identified as promising biomarkers for cancer detection. However, the development of emerging detection methods for piRNAs has not attracted widespread attention. In this work, we proposed an ultrasensitive photoelectrochemical (PEC) biosensor that combines photosensitive hybrid with enzymatic signal amplification strategy for detecting colorectal cancer (CRC)-related piRNA-823. The synergy of the type-II heterostructure between red phosphorus (RP) and black phosphorus (BP), the photothermal effect of BP, and the excellent electron transfer capability and thermoelectric effect of Bi₂Te₃ endowed the BP/RP heterojunction@Bi₂Te₃ hybrid with excellent photoelectric conversion performance. The connection of the poorly conductive composite probe system (SiO₂-COOH-p2-p1) significantly reduced the photocurrent. The target triggered the release of SiO₂-COOH-p2 from the electrode surface and the subsequent specific cleavage of p1 by duplex-specific nuclease, which significantly restored the photocurrent. The released target could react with other composite probes to form a photocurrent signal-increasing cycle. The PEC biosensor showed a linear detection range of 0.1–10⁶ fM and a calculated detection limit of 0.016 fM. In addition, the PEC biosensor exhibited a stable photocurrent response under continuous on-off irradiation and could clearly distinguish the target from the mismatch sequences. The accuracy of the PEC biosensor in detecting piRNA-823 in clinical serum samples was verified by RT–qPCR, and the PEC biosensor could distinguish healthy controls from CRC patients. This work provides a new strategy for ultrasensitive liquid biopsy of piRNAs.

Piwi 相互作用 RNA (piRNA) 是一类非编码小 RNA，已被确定为用于癌症检测的有希望的生物标志物。然而，针对 piRNAs 的新兴检测方法的发展并未引起广泛关注。在这项工作中，我们提出了一种超灵敏的光电化学 (PEC) 生物传感器，该传感器将光敏杂合体与酶促信号放大策略相结合，用于检测结直肠癌 (CRC) 相关的 piRNA-823。_{红磷(RP)和黑磷(BP)的II型异质结构的协同作用、BP的光热效应以及Bi 2} Te ₃优异的电子转移能力和热电效应赋予了BP/RP异质结@Bi ₂ 3 _{_}具有优异的光电转换性能的混合动力。导电性差的复合探针系统（SiO ₂ -COOH-p2-p1）的连接显着降低了光电流。_{该靶标触发了电极表面SiO 2} -COOH-p2的释放，随后双链特异性核酸酶对p1 进行了特异性切割，从而显着恢复了光电流。释放的目标可以与其他复合探针发生反应，形成光电流信号增强循环。PEC 生物传感器的线性检测范围为 0.1-10 ⁶fM 和 0.016 fM 的计算检测限。此外，PEC生物传感器在连续开关照射下表现出稳定的光电流响应，可以清楚地区分目标与错配序列。通过 RT-qPCR 验证了 PEC 生物传感器检测临床血清样本中 piRNA-823 的准确性，并且 PEC 生物传感器可以区分健康对照和 CRC 患者。这项工作为 piRNA 的超灵敏液体活检提供了一种新策略。