Microcantilever array biosensor for simultaneous detection of carcinoembryonic antigens and alpha-fetoprotein based on real-time monitoring of the profile of cantilever.

A microcantilever array biosensor based on sandwich structure has been developed for simultaneously measuring two biomarkers carcinoembryonic antigen (CEA) and alpha-fetoprotein (AFP) via an optical readout technique-real-time monitoring of the profile of cantilever. Firstly the aptamers of CEA and AFP were self-assembled on their respective cantilevers. After the adsorption of the mixture of CEA and AFP, further specific interaction was performed via the addition of the antibodies specific to each target. The compressive stress on the cantilever was generated by aptamer-antigen-antibody sandwich structure formed on the gold surface, resulting in the cantilever bending. The profile of cantilever could be monitored in real time. The relationship between the deflection value at the 90% position of the cantilever and the target concentrations served as a calibration curve and the detection sensitivity was 1.3 ng/mL for CEA and 0.6 ng/mL for AFP, respectively. This work demonstrated the ability of simultaneously measuring two biomarkers via microcantilever array biosensor, giving great potential for further application in detecting several targets simultaneously in early clinical diagnosis.