Enzyme immunoassay using a reusable extended-gate field-effect-transistor sensor with a ferrocenylalkanethiol-modified gold electrode.
A reusable extended-gate field-effect transistor (FET) sensor with an 11-ferrocenyl-1-undecanethiol (11-FUT) modified gold electrode was developed for applying to enzyme immunoassay. It was found that the 11-FUT modified FET sensor detected a thiol compound 50 times or more repeatedly after a treatment with a 5% hydrogen peroxide solution. The gate-voltage shift of the FET sensor showed a fairly good linearity (R(2) = 0.998) within a range from 10(-2) to 10(-6) M on the concentration of 6-hydroxyl-1-hexanethiol, which is a thiol compound, at a Nernstian response of 58.5 mV/decade. The FET-based immunoassay was constructed by combining the 11-FUT modified-FET sensor with the enzyme-linked immunosorbent assay (ELISA), in which the enzyme chemistry of acetylcholinesterase (AChE) was used to generate a thiol compound. The 11-FUT modified FET sensor with an AC voltage at 1 MHz superimposed onto the reference electrode detected the AChE-catalyzed product corresponding to a serum concentration of interleukin 1beta from 10 to 5000 pg/mL. In addition, all measurements were successfully performed by using the same FET-sensor chip after a treatment with a 5% hydrogen peroxide solution.
Kamahori
Masao
M
Central Research Laboratory, Hitachi, Ltd., Kokubunji, Tokyo 185-8601, Japan. masao.kamahori.qj@hitachi.com
Ishige
Yu
Y
Shimoda
Maki
M
D000110:Acetylcholinesterase / Q000378:metabolism; D000818:Animals; D002384:Catalysis; D002417:Cattle; D002623:Chemistry Techniques, Analytical / Q000295:instrumentation*; D004566:Electrodes; D004797:Enzyme-Linked Immunosorbent Assay; D017743:Equipment Reuse; D005296:Ferrous Compounds / Q000737:chemistry*; D006046:Gold / Q000737:chemistry*; D006861:Hydrogen Peroxide / Q000737:chemistry; D007124:Immunoenzyme Techniques / Q000295:instrumentation*; D053583:Interleukin-1beta / Q000032:analysis / Q000276:immunology; D014173:Transistors, Electronic
D005296:Ferrous Compounds; D053583:Interleukin-1beta; D006046:Gold; D006861:Hydrogen Peroxide; D000110:Acetylcholinesterase