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

摘要

A sandwich-type amperometric immunosensor for carcinoembryonic antigen was fabricated by using functionalized carbon nanotubes decorated with concanavalin A along with horseradish peroxidaselabeled carcinoembryonic secondary antibodies. The HRP-Ab_2 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 0.05-5 ng mL~(-1) and 5-200 ng mL~(-1), with a detection limit of 0.018 ng mL~(-1). The biosensor can be used in serum directly.