A novel enzyme immunoassay based on potentiometric measurement of molecular adsorption events by an extended-gate field-effect transistor sensor

Surface-modified silicon nano-channel for urea sensing

“…Since the concept of ISFET (ion sensitive field-effect transistor) was first introduced in biosensor applications by Bergveld [1], it has attracted a lot of interest among both experimentalists and theorists [2][3][4][5][6]. The surface of the gate of the FET device can be modified with sensing molecules like antibody or antigen, and has the potential for serving as a highly efficient immunological sensor with the required specificity and sensitivity [7].…”

Enzyme Immunoassay Using a Reusable Extended-gate Field-Effect-Transistor Sensor with a Ferrocenylalkanethiol-modified Gold Electrode

“…The sandwich immunoassay is the same procedure as described previously. 16 First, an antigen and an enzyme-labeled antibody (second antibody) are sequentially added to a microplate, in which a first antibody is immobilized. After bound/free (B/F) separation, an enzyme substrate solution is added to the microplate, and a thiol compound is produced by the labeled enzyme.…”

“…13,14 Recently, we developed a novel enzyme immunoassay based on a potentiometric measurement of molecular adsorption events by an extended-gate FET sensor. 16 An enzyme immunoassay by using the extended-gate FET sensor was combined with ELISA, in which the enzyme chemistry of AChE to generate a thiol compound was used. The generating thiol compounds adsorb easily on the gold electrode shown in Figs.…”

“…16 The procedure for the enzyme immunoassay is as follows. Each well of the microtiter plate was coated with a monoclonal antibody for IL-1b (IL-1b capture antibody).…”

“…based on a potentiometric measurement of molecular adsorption events on a gold electrode of an extended-gate FET sensor has been reported. 16 As a labeled enzyme, acetylcholinesterase (AChE) is a high-turnover enzyme, and has played the role of generating thiol compounds, which adsorb easily on the gold electrode. The interface potential on the gold electrode of the FET sensor has been shown to shift in the negative direction as a result of the adsorption of a thiol compound on the gold electrode, and the adsorption rate was related to the concentration of the antibody-antigen complex, i.e., the target in the sample.…”