Development of an impedimetric immunobiosensor for measurement of carcinoembryonic antigen

•The biosensor integrated the electrode microchip and improved sandwich immunoassay to detect the CEA concentration.•The detection limit for CEA concentration was 1 ng/mL with 1 μg/mL of anti-CEA antibody and 30X of the AuNPs-anti-CEA antibody.•The biosensor has many advantages, such as smaller sample volumes (25 μL), rapid quantitative measurements (10 min), and smaller detectable concentrations than those of the currently available commercial detection products (CEA rapid test strip with the best limit of detection of 5 ng/mL).

This paper presents an impedimetric immunobiosensor for detecting the impedance signals of various concentrations of carcinoembryonic antigen (CEA), a type of protein molecule which is typically associated with certain tumors. The biosensor was developed by parallel electrodes and improved sandwich immunoassay, and used specific binding of antibodies to change the impedance signals of various CEA concentrations. We observed an obvious difference in impedance signals after 13 min, and a better linearity (a steep slope between impedance and CEA concentration) at 100 Hz. Finally, when the concentration of the AuNPs-anti-CEA antibody was diluted 30 for times, the detection limit for CEA concentration was 1 ng/mL with 1 μg/mL of anti-CEA antibody. Therefore, the developed biosensor has advantages including smaller sample volume (25 μL), rapid quantitative measurement (10 min), and smaller detectable concentrations (1 ng/mL).