Enzyme-mediated signal amplification strategies have gained substantial attention in photoelectrochemical (PEC) biosensing, while natural enzyme on the photoelectrode inevitably obstructs the interfacial electron transfer, in turn deteriorating the photocurrent responses. Herein, Au nanoparticles and Cu²⁺-modified boron nitride nanosheets (AuNPs/Cu²⁺-BNNS) behaved as nanozyme to achieve remarkable magnification in the PEC signals from a novel signal-off aptasensor for ultra-sensitive assay of telomerase (TE) activity based on Ag₂S/Ag nanoparticles decorated ZnIn₂S₄/C₃N₄ Z-scheme heterostructures (termed as Ag₂S/Ag/ZnIn₂S₄/C₃N₄, synthesized by hydrothermal treatment). Specifically, telomerase primer sequences (TS) were extended by TE in the presence of deoxyribonucleoside triphosphates (dNTPs), which was directly bond with the thiol modified complementary DNA (cDNA), achieving efficient linkage with the nanozyme via Au–S bond. The immobilized nanoenzyme catalyzed the oxidation between 4-chloro-1-naphthol (4-CN) and H₂O₂ to generate insoluble precipitation on the photo-electrode. By virtue of the inhibited PEC signals with the TE-enabled TS extension, an aptasensor for assay of TE activity was developed, showing the wide linear range of 50–5×10⁵ cell mL^-1 and a low detection limit of 19 cell mL^-1. This work provides some valuable guidelines for developing advanced nanozyme-based PEC bioanalysis of diverse cancer cells.

酶介导的信号放大策略在光电化学 (PEC) 生物传感中引起了广泛关注，而光电极上的天然酶不可避免地阻碍了界面电子转移，进而恶化了光电流响应。在此，Au 纳米颗粒和 Cu ²⁺修饰的氮化硼纳米片 (AuNPs/Cu ²⁺ -BNNS) 可作为纳米酶实现来自新型信号关闭适体传感器的 PEC 信号的显着放大，用于端粒酶 (TE) 的超灵敏测定基于 Ag ₂ S/Ag 纳米粒子的活性修饰 ZnIn ₂ S ₄ /C ₃ N ₄ Z 型异质结构（称为 Ag ₂ S/Ag/ZnIn₂ S ₄ /C ₃ N ₄，通过水热处理合成）。具体来说，在脱氧核糖核苷三磷酸（dNTPs）存在的情况下，端粒酶引物序列（TS）被TE延伸，dNTPs直接与硫醇修饰的互补DNA（cDNA）键合，通过Au-S键与纳米酶有效连接。固定化的纳米酶催化4-氯-1-萘酚（4-CN）和H ₂ O ₂之间的氧化，在光电极上产生不溶性沉淀。凭借 TE 启用的 TS 扩展抑制 PEC 信号，开发了一种用于检测 TE 活性的适体传感器，显示出 50-5 × 10 ^{5的宽线性范围} 细胞 mL ^-1和 19 个细胞 mL ^-1的低检测限。这项工作为开发先进的基于纳米酶的不同癌细胞的 PEC 生物分析提供了一些有价值的指导。