Herein, a new type of multifunctional iron based metal-organic frameworks ([email protected]) has been synthesized by assembly palladium nanoparticles on the surface of Fe-MIL-88NH₂ MOFs microcrystals, and first applied in electrochemical biosensor for ultrasensitive detection of microRNA-122 (miR-122, a biomarker of drug-induced liver injury). The nanohybrids have not only been utilized as ideal nanocarriers for immobilization of signal probes, but also used as redox probes and electrocatalysts. In this biosensor, two hairpin probes were designed as capture probes and signal probes, respectively. The nanohybrids conjugated with streptavidin and biotinylated signal probes were used as the tracer labels, target miR-122 was sandwiched between the tracer labels and thiol-terminated capture probes inserted in MCH monolayer on the gold nanoparticles-functionalized nitrogen-doped graphene sheets ([email protected]) modified electrode. Based on target-catalyzed hairpin assembly, target miR-122 could trigger the hybridization of capture probes and signal probes to further be released to initiate the next reaction process resulted in numerous tracer indicators anchored onto the sensing interfaces. Thus, the detection signal could be dramatically enhanced towards the electrocatalytic oxidation of 3,3′,5,5′-tetramethylbenzidine in the presence of H₂O₂ owing to the intrinsic and intriguing peroxidase-like activity of the nanohybrids. With the assist of target-catalyzed hairpin assembly and [email protected] mimetic co-reaction for signal amplification, a wide detection range from 0.01 fM to 10 pM was achieved with a low detection limit of 0.003 fM (S/N =3). Furthermore, the proposed biosensor exhibited excellent specificity and recovery in spiked serum samples, and was successfully used for detecting miR-122 in real biological samples, which provided a rapid and efficient method for detecting drug-induced liver injury at an early stage.

本文中，通过在Fe-MIL-88NH ₂表面组装钯纳米粒子，合成了一种新型的多功能铁基金属有机骨架（[受电子邮件保护]）MOF是微晶，首先应用于电化学生物传感器中，用于超灵敏地检测microRNA-122（miR-122，药物诱导的肝损伤的生物标志物）。纳米杂合物不仅被用作固定信号探针的理想纳米载体，而且还用作氧化还原探针和电催化剂。在该生物传感器中，将两个发夹式探针分别设计为捕获探针和信号探针。结合有链霉亲和素和生物素化信号探针的纳米杂交物用作示踪标记，将目标miR-122夹在示踪标记和硫醇封端的捕获探针之间，该探针插入金纳米颗粒功能化的氮掺杂石墨烯片的MCH单层中（[email保护]）的电极。基于目标催化的发夹装配，靶标miR-122可以触发捕获探针和信号探针的杂交，使其进一步释放以启动下一个反应过程，从而导致大量示踪剂指示物锚定在传感界面上。因此，在H存在下，检测信号可以显着增强3,3'，5,5'-四甲基联苯胺的电催化氧化₂ O ₂归因于纳米杂化物的固有的和有趣的过氧化物酶样活性。借助目标催化的发夹装配和[电子邮件保护]模拟共反应进行信号放大，可实现0.01 fM至10 pM的宽检测范围，而低检测限为0.003 fM（S / N = 3）。此外，所提出的生物传感器在加标血清样品中表现出优异的特异性和回收率，并成功地用于检测真实生物样品中的miR-122，这为早期检测药物诱发的肝损伤提供了一种快速有效的方法。