Electrochemical lectin-based biosensor array for detection and discrimination of carcinoembryonic antigen using dual amplification of gold nanoparticles and horseradish peroxidase

Abstract An electrochemical lectin-based biosensor array employing lectin as molecular recognition elements was developed for sensitive detection and discrimination of carcinoembryonic antigen (CEA) based on dual signal amplification of gold nanoparticles and enzymatic catalysis. The electrochemical biosensor was fabricated by self-assembly of cysteamine on the surface of gold nanoparticle-modified screen-printed carbon electrodes and subsequently covalently coupling lectins on the surface of the cysteamine-modified electrode via the amidation reaction. A lectin–target-antibody sandwich-type conjugate was formed when the biosensor was successively reacted with target protein and horseradish peroxidase labeled anti-CEA antibody probe. In the presence of hydroquinone and hydrogen peroxide, the resulted biosensor produced an obvious catalysis current signal. The catalytic current at −0.25 V was linear with the concentration of CEA in the range of 1 ng/mL to 10 ng/mL with detection limit of 0.03 ng/mL and 0.05 ng/mL using concanavalin A and wheat-germ agglutinin as molecular recognition element, respectively, and in the range of 0.5 ng/mL to 7 ng/mL with detection limit of 0.01 ng/mL using Lens culinaris agglutinin as molecular recognition element. Additionally, the lectin-based biosensor array was successfully applied to evaluate the glycan expression of CEA N -glycan and discriminate CEA between healthy and cancer serum samples. The lectin-based biosensor array endows a feasibility tool for clinical diagnosis in complex biological systems and shows great promise for cancer detection and further pathological study of carcinogenesis.