Bioassay of Carcinoembryonic Antigens by Organic Field-effect Transistors Based on D-A Type Conjugated Polymer

Biosensors based on organic field-effect transistors(OFETs) are one of the most promising electronic devices for emerging bioanalytical applications. The selection of organic semiconductors(OSCs) is essential to improve the sensitivity and reliability of this kind of biosensors. Given the good field effect performance and tunable structures of D-A type conjugated polymers, here, we design two D-A type copolymers[P(BDT-co-DPP2T-ThC2) and P(BDT-co-DPP2T-Th)], which are applied as the OSC layers. With carcinoembryonic antigen antibody(anti-CEA) adsorbed onto the OSC layers as the recognition sites, OFETs based biosensors for CEA detection are developed. The experimental findings support that the attachment of ester side groups onto the polymer backbone[as for P(BDT-co-DPP2T-ThC2)] is favorable for improved solubility and filming properties of the polymer. The introduction of ester side groups affects molecular stacking and enhances intermolecular forces. The resultant devices show high charge mobility and antibody adsorption ability, both of which are critical for sensitive and facile detection of CEA biomarkers. The reliable determination of CEA down to the picomolar level is determined. It is expected that this kind of biosensors fabricated by D-A type conducting polymers will open new avenues toward the early diagnosis, real-time monitoring and treatment of future cancer diseases.