Designed antifouling peptides planted in conducting polymers through controlled partial doping for electrochemical detection of biomarkers in human serum

An antifouling electrochemical biosensing platform was constructed based on conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) planted with designed peptides. The designed peptides containing doping and antifouling sequences were anchored to an electrode surface, followed by the electrochemical polymerization of PEDOT. The negatively charged doping sequence of the peptide was gradually doped into the PEDOT during the polymerization process, and by controlling the polymerization time, it was able to exactly dope the whole doping sequence into the PEDOT film, leaving the antifouling sequence of the peptide stretched out of the PEDOT surface. Therefore, an excellent conducting and antifouling platform was constructed just like planting a peptide tree in the PEDOT soil. With antibodies immobilized on the peptide, an antifouling electrochemical biosensor for the detection of a typical biomarker CA15-3 was developed. Owing to the unique properties of the conducting polymer PEDOT and the antifouling peptide, the electrochemical biosensor exhibited high sensitivity and long-term stability, and it was capable of detecting CA15-3 in serum of breast cancer patients without suffering from biofouling. The strategy of planting designed antifouling peptides in conducting polymers offered an effective way to develop electrochemical sensors for practical biomarkers assaying in complex biological samples.