Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749, South Korea.
Korea Institute of Ceramic Engineering and Technology (KICET), Jin-Ju, South Korea.
Anal Chim Acta. 2019 Sep 27;1073:30-38. doi: 10.1016/j.aca.2019.04.054. Epub 2019 Apr 25.
Highly N-doped SiC was presented as an optimal electrode for electrochemical immunoassays with a far higher sensitivity than chemiluminescence detection. As the first step, the electrochemical properties of highly N-doped SiC, such as the double-layer capacitance (C), rate constant for electron transfer (k) and ideal polarizable potential range (electrochemical window) were analyzed and compared with those of Au, Pt, and graphite electrodes. The highly N-doped SiC electrode was used for the quantification of oxidized 3,3',5,5'-tetramethylbenzidine (TMB) which was widely used as chromogenic substrate for commercialized immunoassay kits. In order to enhance the sensitivity for the quantification of the oxidized TMB the chronoamperometry was applied to avoid the background current of i-V measurement. Finally, the chronoamperometry based on the highly N-doped SiC electrode was applied to commercial immunoassay kits for the medical diagnosis of the human immunodeficiency virus (HIV) and the human hepatitis B surface antigen (hHBsAg). The chronoamperometric measurement based on the highly N-doped SiC electrode was proved to detect at far lower limits in comparison with the conventional optical density measurement as well as the chemiluminescence assay based on luminol as a chemiluminescent probe.
高掺杂碳化硅被提出作为电化学免疫分析的最佳电极，其灵敏度远高于化学发光检测。作为第一步，分析了高掺杂碳化硅的电化学性质，如双电层电容（C）、电子转移速率常数（k）和理想可极化电位范围（电化学窗口），并与金、铂和石墨电极进行了比较。高掺杂碳化硅电极用于定量氧化 3,3',5,5'-四甲基联苯胺（TMB），TMB 广泛用作商业化免疫分析试剂盒的显色底物。为了提高氧化 TMB 定量的灵敏度，应用计时安培法来避免 i-V 测量的背景电流。最后，将基于高掺杂碳化硅电极的计时安培法应用于商业免疫分析试剂盒，用于人类免疫缺陷病毒（HIV）和乙型肝炎表面抗原（hHBsAg）的医学诊断。与传统的光密度测量以及基于鲁米诺的化学发光测定相比，基于高掺杂碳化硅电极的计时安培测量被证明可以检测到更低的下限。
