title: Band-type microelectrodes for amperometric immunoassays.
abstract: A band-type microelectrode was made using a parylene-N film as a passivation layer. A circular-type, mm-scale electrode with the same diameter as the band-type microelectrode was also made with an electrode area that was 5000 times larger than the band-type microelectrode. By comparing the amperometric signals of 3,5,3',5'-tetramethylbenzidine (TMB) samples at different optical density (OD) values, the band-type microelectrode was determined to be 9 times more sensitive than the circular-type electrode. The properties of the circular-type and the band-type electrodes (e.g., the shape of their cyclic voltammograms, the type of diffusion layer used, and the diffusion layer thickness per unit electrode area) were characterized according to their electrode area using the COMSOL Multiphysics software. From these simulations, the band-type electrode was estimated to have the conventional microelectrode properties, even when the electrode area was 100 times larger than a conventional circular-type electrode. These results show that both the geometry and the area of an electrode can influence the properties of the electrode. Finally, amperometric analysis based on a band-type electrode was applied to commercial ELISA kits to analyze human hepatitis B surface antigen (hHBsAg) and human immunodeficiency virus (HIV) antibodies.
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749, South Korea.
authors.forename: Ga-Yeon
authors.initials: GY
authors.lastname: Lee
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749, South Korea.
authors.forename: Young Wook
authors.initials: YW
authors.lastname: Chang
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749, South Korea.
authors.forename: Hyuk
authors.initials: H
authors.lastname: Ko
authors.affiliation: Korea Institute of Science and Technology (KIST), Seoul, South Korea.
authors.forename: Min-Jung
authors.initials: MJ
authors.lastname: Kang
authors.affiliation: Department of Materials Science and Engineering, Yonsei University, 134 Shinchon-dong, Seodaemun-gu, Seoul, 120-749, South Korea. Electronic address: jcpyun@yonsei.ac.kr.
authors.forename: Jae-Chul
authors.initials: JC
authors.lastname: Pyun
mesh_terms: D001560:Benzidines / Q000737:chemistry; D004058:Diffusion; D004563:Electrochemistry / Q000295:instrumentation*; D004867:Equipment Design; D007118:Immunoassay / Q000295:instrumentation*; D008839:Microelectrodes; D011108:Polymers / Q000737:chemistry; D014992:Xylenes / Q000737:chemistry
chemical_list: D001560:Benzidines; D011108:Polymers; D014992:Xylenes; C011055:parylene; C021758:3,3',5,5'-tetramethylbenzidine
keywords: Amperometry; Band-type; Immunoassay; Microelectrode; Parylene; Simulation