Electrochemical immunoassays are often used in the detection of biomarkers, and their sensitivity depends on the nature of the substrate and the catalytic activity of the signal amplification platform. In this work, a novel sandwich-type signal amplification strategy with a “gold-plated” organometallic frame (Au/IRMOF-3) as the substrate and the sea cucumber-like Pd@PtRh trimetallic nanomaterial (Pd@PtRh SNRs) as label was fabricated. For the substrate, gold nanoparticles (Au NPs) are stably connected to the free amino groups on the surface of organometallic frame (IRMOF-3), which not only prevent the agglomeration of Au NPs, but also greatly enhance the conductivity of the nanocomposites. The synergy between the two nanomaterials further shows a stronger affinity for the fixation of capture antibodies (Ab₁). For the label, the effective high catalytic activity comes from the Pd@PtRh SNRs with a sea cucumber-like morphology. The nano-scale spherical PtRh crystals epitaxially grown on smooth Pd nanorods (Pd NRs) have more catalytically active sites because of the abundant edge and corner atoms, resulting in high catalytic activity and durability towards H₂O₂ reduction. Choosing calcitonin (PCT) as the target, differential pulse voltammetry (DPV) and amperometric i-t dual-mode detection was used to demonstrate the feasibility of the immunosensor. The results confirmed that the immunosensor exhibits excellent analytical capabilities and is satisfied in the analysis of human serum samples. Therefore, this strategy has great potential in the clinical application of electrochemical immunosensors.

电化学免疫测定法常用于生物标志物的检测，其灵敏度取决于底物的性质和信号放大平台的催化活性。在这项工作中，以“镀金”有机金属框架（Au / IRMOF-3）为底物和海参状Pd @ PtRh三金属纳米材料（Pd @ PtRh SNRs）为标记的新型三明治型信号放大策略被捏造了。对于基材，金纳米颗粒（Au NPs）稳定地连接到有机金属框架（IRMOF-3）表面的游离氨基上，这不仅可以防止Au NPs的团聚，而且可以大大提高纳米复合材料的电导率。两种纳米材料之间的协同作用进一步显示出对捕获抗体（Ab₁）。对于标签，有效的高催化活性来自具有海参状形态的Pd @ PtRh SNR。外延生长在光滑的Pd纳米棒（Pd NRs）上的纳米级球形PtRh晶体由于具有丰富的边缘和角原子，因此具有更多的催化活性位，从而具有较高的催化活性和对H ₂ O _2的耐久性减少。选择降钙素（PCT）作为靶标，差分脉冲伏安法（DPV）和安培双模式检测被用于证明免疫传感器的可行性。结果证实了该免疫传感器表现出优异的分析能力并且在人血清样品的分析中令人满意。因此，该策略在电化学免疫传感器的临床应用中具有很大的潜力。