Cardiac troponin I (cTnI) is considered to be the most valuable biomarker for the diagnosis of acute myocardial infarction (AMI). The sensitive and efficient determination of cTnI is essential for the early diagnosis and prognostic assessment of AMI. In this paper, we designed for the first time an electrochemical immunosensor based on the ring-opening polymerization (ROP) reaction as a signal amplification strategy for the highly sensitive detection of cTnI. Briefly, 3-mercaptopropionic acid (MPA) was used as a cross-linking agent to immobilize Ab₁ on the surface of gold electrodes, and subsequently Ab₁ specifically captured cTnI. Then, the glycolic acid-coupled cTnI-secondary antibody (GA-Ab₂) bound specifically to cTnI to form a sandwich structure and provided the initiation site for the subsequent polymerization reaction. Subsequently, ferrocene formyloxyate propylene oxide (FFAPO) was used as the monomer and large quantities of electroactive polymers were grafted to the electrode surface via a hydroxyl-initiated ROP reaction, which significantly amplified the electrochemical signal. Under optimal conditions, the immunosensor displayed good linearity in the concentration range of 1 pg mL⁻¹–1 μg mL⁻¹ and the limit of detection down to 57.14 fg mL⁻¹, which was superior to most of those reported assays. Compared to other signal amplification strategies, this ROP reaction showed relatively easy access to raw materials and comparatively mild reaction conditions. In addition, the results of the serum sample detection capability indicated that the immunosensor exhibited excellent detection selectivity and reliability in serum. Thus, owing to its good selectivity, high sensitivity and excellent stability, the immunosensor shows great potential for clinical application.

心肌肌钙蛋白 I (cTnI) 被认为是诊断急性心肌梗死 (AMI) 最有价值的生物标志物。cTnI 的灵敏和有效测定对于 AMI 的早期诊断和预后评估至关重要。在本文中，我们首次设计了一种基于开环聚合（ROP）反应的电化学免疫传感器作为信号放大策略，用于高灵敏度检测 cTnI。简而言之，使用 3-巯基丙酸 (MPA) 作为交联剂将 Ab ₁固定在金电极表面，随后 Ab ₁特异性捕获 cTnI。然后，乙醇酸偶联 cTnI-二抗 (GA-Ab ₂) 与 cTnI 特异性结合形成夹层结构，并为随后的聚合反应提供起始位点。随后，以二茂铁甲酰氧基环氧丙烷（FFAPO）为单体，通过羟基引发的ROP反应将大量电活性聚合物接枝到电极表面，显着放大了电化学信号。^{在最佳条件下，免疫传感器在 1 pg mL -1} –1 μg mL ^-1的浓度范围内表现出良好的线性，检测限低至 57.14 fg mL ^-1，这优于大多数报告的化验。与其他信号放大策略相比，该ROP反应显示出相对容易获得原料和相对温和的反应条件。此外，血清样本检测能力的结果表明，该免疫传感器在血清中表现出优异的检测选择性和可靠性。因此，由于其良好的选择性、高灵敏度和优异的稳定性，免疫传感器显示出巨大的临床应用潜力。