Enzyme immunosensors based on electropolymerized polytyramine modified electrodes.
Highly sensitive amperometric enzyme immunosensors for human immunoglobulin G (IgG) were prepared on the basis of electrogenerated polytyramine (PTy, tyramine = p-(2-aminoethyl)-phenol) modified electrodes. Properties of PTy films changed depending on electrolysis conditions. On the basis of the found properties of the films, an effective IgG sensor was prepared: a PTy film was formed first from an acid solution on a Pt electrode, and the surface was further covered with a PTy film from an alkaline methanol solution to give a PTy doubly coated electrode on which anti-IgG was then immobilized. This electrode provided a large surface area with little non-specific adsorption of proteins. By means of the competitive enzyme immunoassay technique using glucose oxidase (GOD) labeled IgG conjugates, IgG was determined in the concentration range of c. 10 pg/ml-1 mg/ml from the oxidation current of H2O2 generated by the enzyme (GOD) reaction using the above IgG sensor. Also, an anti-IgG immobilized electrode, prepared by using a Pt electrode singly covered with a PTy film from an alkaline methanol solution, acted as an effective IgG sensor with a detection limit for IgG of c. 100 pg/ml.
Department of Applied Chemistry, Faculty of Engineering, Kumamoto University, Japan.
I
I
Tsuji
H
H
Eguchi
K
K
Yasukouchi
M
M
Unoki
I
I
Taniguchi
D000888:Antibodies, Anti-Idiotypic; D015374:Biosensing Techniques; D005949:Glucose Oxidase; D006801:Humans; D007124:Immunoenzyme Techniques; D007074:Immunoglobulin G / Q000032:analysis*; D011108:Polymers; D014439:Tyramine
D000888:Antibodies, Anti-Idiotypic; D007074:Immunoglobulin G; D011108:Polymers; D005949:Glucose Oxidase; D014439:Tyramine