Microbiochip-based Immunoassay with Branching Multichannel for Simultaneous Detection of Cancer Biomarker

Abstract

We have developed and characterized a microbiochip which can simultaneously detect three cancer biomarkers by using microbeads, gold nanoparticles and silver enhancer. The integrated microbiochip that includes a Pt electrode to measure an electrical signal and a microfilter to fix the microbeads was fabricated. We adopted a filtration method using microbeads to immobilized antibody and immuno-gold silver staining (IGSS) method to amplify electrical signals. Cancer biomarkers, α-fetoprotein (AFP), carcinoembryonic antigen (CEA) and prostate-specific antigen (PSA), were successfully assayed by a sandwich immunoassay with this system. We could simultaeously perform the immunoassay of three cancer markers within one hour. We could verify three orders difference of electrical signal between immunoassay results of each marker and that of control. the detection limit of our microbiochip system was 1 ng/ml for each marker. Our microbiochip system could have potential application to clinical diagnosis with short analysis time.