A carbon nanowire-modified surface with interdigitated electrode (IDE) sensing system was introduced to identify abdominal aortic aneurysm biomarker “papain,” also known as cysteine protease, used as the capture probe to identify Cystatin C. Papain was immobilized through the covalent integration of amine group on papain and the carboxyl group with carbon nanowire. This papain-modified electrode surface was utilized to detect the different concentrations of Cystatin C (100 pg/mL to 3.2 ng/mL). The interaction between papain and Cystatin C was monitored using a picoammeter, and the response curves were compared. With increasing Cystatin C concentrations, the total current levels were gradually increased with a linear range from 200 pg/mL to 3.2 ng/mL, and the current differences were plotted and the detection limit of Cystatin C was calculated as 200 pg/mL. The averaging of three independent experiments (n = 3) was made with 3δ estimation, and the determination coefficient was y = 1.8477 × 0.7303 and R² = 0.9878. Furthermore, control experiments with creatinine and gliadin failed to bind the immobilized papain, indicating the specific detection of Cystatin C.

中文翻译：

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碳纳米线叉指电极表面上的电流-伏生物传感“胱抑素 C”：膨胀主动脉的临床标志物分析

引入了具有叉指电极 (IDE) 传感系统的碳纳米线修饰表面，以识别腹主动脉瘤生物标志物“木瓜蛋白酶”，也称为半胱氨酸蛋白酶，用作识别胱抑素 C 的捕获探针。木瓜蛋白酶通过共价整合固定化木瓜蛋白酶上的胺基和碳纳米线上的羧基。这种木瓜蛋白酶修饰的电极表面用于检测不同浓度的胱抑素 C（100 pg/mL 至 3.2 ng/mL）。使用皮安计监测木瓜蛋白酶和胱抑素 C 之间的相互作用，并比较响应曲线。随着胱抑素 C 浓度的增加，总电流水平逐渐增加，线性范围从 200 pg/mL 到 3.2 ng/mL，并绘制电流差，计算Cystatin C的检测限为200 pg/mL。三个独立实验的平均值（n  =  3 ) 采用 3 δ估计，决定系数为y  = 1.8477 × 0.7303 和R ²  = 0.9878。此外，肌酐和麦醇溶蛋白的对照实验未能结合固定的木瓜蛋白酶，表明对胱抑素 C 的特异性检测。