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 (Cdl), rate constant for electron transfer (kapp) 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.
Bibliographical noteFunding Information:
The authors thank to Dr. Yun-Ji Shin (Korea Institute of Ceramic Engineering and Technology, Jin-Ju, Korea) for the valuable discussion with Dr. This work was supported by the Nano-Convergence Foundation [grant number: R201602210 ] funded by the Ministry of Science , ICT and Future Planning (MSIP, Korea) and Ministry of Trade , Industry and Energy (MOTIE, Korea) and the National Research Foundation of Korea [grant numbers: NRF-2017R1A2B4004077 , NRF-2017R1A6A3A11034081 ].
All Science Journal Classification (ASJC) codes
- Analytical Chemistry
- Environmental Chemistry