标题：Thionin functionalized signal amplification label derived dual-mode electrochemical immunoassay for sensitive detection of cardiac troponin I
作者：Lv, Hui; Li, Yueyun; Zhang, Xiaobo; Li, Xinjin; Xu, Zhen; Chen, Lei; Li, Degang; Dong, Yunhui
作者机构：[Lv, Hui; Li, Yueyun; Zhang, Xiaobo; Li, Xinjin; Xu, Zhen; Chen, Lei; Li, Degang; Dong, Yunhui] Shandong Univ Technol, Sch Chem & Chem Engn, Zibo 2550 更多
通讯作者：Li, Yueyun;Li, YY;Li, DG
通讯作者地址：[Li, YY; Li, DG]Shandong Univ Technol, Sch Chem & Chem Engn, Zibo 255049, Peoples R China.
来源：BIOSENSORS & BIOELECTRONICS
关键词：Sandwich-type electrochemical immunosensor; Double signal label; Cardiac; troponin I; Differential pulse voltammetry; Amperometric i-t
摘要：A sensitive sandwich-type electrochemical immunosensor was established by employing Au@Pt core-shell multi-branched nanoparticles, and thionin functionalized nitrogen/sulfur co-doped graphene oxide (N/S-cGO/L-lys/Au@Pt MBs/Thi) as a double signal label to detect cardiac troponin I (cTnI). In this work, Au nanorods functionalized polydopamine (Au NR@PDA) with high adsorption capacity and superior electroconductivity can provide an efficient substrate for immobilizing primary antibodies (Ab(1)). In the proposed N/S-cGO/L-lys/Au@Pt MBs/Thi, an electrochemically active molecule, Thi was covalently bonded in the N/S-cGO/L-lys/Au@Pt MBs. It presented a strong differential pulse voltammetry (DPV) current signal without electron transfer mediators, and showed a high electrocatalytic activity toward H2O2 reduction by using amperometric i-t (i-t). Impressively, with the synergistic effect of N/S-cGO/t-lys/Au@Pt MBs/Thi and Au NR@PDA, the developed dual-mode electrochemical immunosensor for cTnI detection showed a wide linear concentration range (50 fg/mL to 250 ng/mL, 750 fg/mL to 100 ng/mL) and a low detection limit (16.7 fg/mL, 250 fg/mL) via i-t and DPV, respectively. Furthermore, this immunosensor exhibited acceptable reproducibility, high sensitivity and good stability under optimal conditions. More importantly, the satisfactory results were obtained in detection of cTnI-spiked human serum samples, and the presented method may be a promising application in clinical bioanalysis.