A direct electrochemistry of silver nanoparticles (AgNPs)-anchored metal-organic frameworks (MOFs) is developed for detection of telomerase activity based on allosteric activation of an aptamer hairpin. AgNPs in situ decorated on PCN-224 (AgNPs/PCN-224) constituted the direct electrochemical labels that were further biofunctionalized by recognition moiety of streptavidin (SA). To achieve the target biosensing, an allosteric hairpin-structured DNA was elaborately designed for signal transduction. The presence of telomerase elongated its primer in the hairpin to displace partial stem strand, thus resulted in the formation of SA aptamer-open structure. Through the specific interaction with aptamer, SA-biofunctionalized AgNPs/PCN-224 probe was attached onto the electrode surface, generating electrochemical signal at + 0.072 V of AgNPs centralized by MOF structure. The direct electrochemical biosensor showed target activity-dependent response from 1.0 × 10⁻⁷ to 1.0 × 10⁻¹ IU L⁻¹ with a detection limit of 5.4 × 10⁻⁸ IU L⁻¹. Moreover, the sensor was applied in evaluation of telomerase activity in living cancer cells. The established electrochemical detection approach in this work avoids the critical deoxygenation conditions and additional electrocatalytic reagents, which opens a novel biosensing perspective for direct electrochemistry of MOF-based nanocomposites.

开发了银纳米粒子 (AgNPs) 锚定金属有机框架 (MOF) 的直接电化学，用于检测基于适体发夹变构激活的端粒酶活性。AgNPs原位装饰在 PCN-224 (AgNPs/PCN-224) 上的直接电化学标记物通过链霉亲和素 (SA) 的识别部分进一步生物功能化。为了实现目标生物传感，精心设计了变构发夹结构的 DNA 用于信号转导。端粒酶的存在延长了其在发夹中的引物以取代部分茎链，从而导致SA适体开放结构的形成。通过与适体的特异性相互作用，SA 生物功能化的 AgNPs/PCN-224 探针连接到电极表面，在 + 0.072 V 的 AgNPs 由 MOF 结构集中产生电化学信号。直接电化学生物传感器显示目标活性依赖性响应从 1.0 × 10 ^-7到 1.0 × 10 ^-1 IUL ^-1检测限为5.4 × 10 ^-8 IUL ^-1。此外，该传感器还用于评估活癌细胞中的端粒酶活性。在这项工作中建立的电化学检测方法避免了临界脱氧条件和额外的电催化试剂，这为基于 MOF 的纳米复合材料的直接电化学开辟了新的生物传感视角。