Sandwich-type amperometric immunosensor for cancer biomarker based on signal amplification strategy of multiple enzyme-linked antibodies as probes modified with carbon nanotubes and concanavalin A

Abstract

A sandwich-type amperometric immunosensor for carcinoembryonic antigen was fabricated by using functionalized carbon nanotubes decorated with concanavalin A along with horseradish peroxidase-labeled carcinoembryonic secondary antibodies. The HRP-Ab2 was assembled onto carbon nanotubes templates based on the biospecific affinity between concanavalin A and HRP. The carcinoembryonic antibody was immobilized on the gold electrode modified by monolayer cysteine. The response is linear in the range of 0.05–5ngmL−1 and 5–200ngmL−1, with a detection limit of 0.018ngmL−1. The biosensor can be used in serum directly.