The C-peptide is a co-product of pancreatic β-cells during insulin secretion; its content in body fluid is closely related to diabetes. This paper reports an immune-sensing strategy for a simple and effective assay of C-peptide based on label-free electrochemiluminescent (ECL) signaling, with high sensitivity and specificity. The basal electrode was constructed of an indium tin oxide (ITO) glass as a conductive substrate, which was decorated by Au nanoparticles (AuNPs) with hydrolysed (3-aminopropyl)trimethoxysilane as the linker. The characteristics of the fabricated electrode were investigated by electron microscopy, cyclic voltammetry, and electrochemical impedance spectroscopy. After immobilizing the C-peptide antibody, which takes great advantage of AuNPs' binding capacity, this immunosensor can quantify C-peptide using luminol as the ECL probe. By measuring ECL inhibition, calibration can be established to report the C-peptide concentration between 0.05 ng mL⁻¹ and 100 ng mL⁻¹ with a detection limit of 0.0142 ng mL⁻¹. As a proof of concept, the proposed strategy is a promising and versatile platform for the clinical diagnosis, classification, and research of diabetes.

C肽是胰岛素分泌过程中胰腺β细胞的副产物。它在体液中的含量与糖尿病密切相关。本文报道了一种基于无标记电化学发光（ECL）信号的简单有效的C肽检测方法，具有很高的灵敏度和特异性，是一种免疫传感策略。基础电极由氧化铟锡（ITO）玻璃制成，作为导电衬底，并由以水解的（3-氨丙基）三甲氧基硅烷为连接基的Au纳米颗粒（AuNPs）装饰。通过电子显微镜，循环伏安法和电化学阻抗谱研究了制成的电极的特性。固定化了利用AuNPs结合能力的C肽抗体后，该免疫传感器可以使用鲁米诺作为ECL探针来定量C肽。通过测量ECL抑制作用，可以建立校准以报告0.05 ng mL之间的C肽浓度^-1和100 ng mL ^-1，检出限为0.0142 ng mL ^-1。作为概念的证明，所提出的策略是用于糖尿病的临床诊断，分类和研究的有前途且用途广泛的平台。