A low fouling electrochemical biosensor based on the zwitterionic polypeptide doped conducting polymer PEDOT for breast cancer marker BRCA1 detection.

The application of polypeptides in bio-interfaces and biosensors is of great interest because polypeptides are biocompatible and easy to design. A novel polymer nanocomposite was prepared by the electropolymerization of the conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) with a newly designed polypeptide. The nanocomposite polypeptide doped PEDOT (PEDOT/PEP), with a 3D microporous network structure, large surface area and excellent antifouling ability, was utilized for the attachment of BRCA1 complementary oligonucleotides to construct a DNA biosensor. The fabricated DNA biosensor showed favorable selectivity (with a detection limit of 0.0034 pM) and high sensitivity. The biosensor was also capable of detecting the target DNA (BRCA1) in 1% (V/V) human serum samples. The combination of a conducting polymer PEDOT with an antifouling and biocompatible polypeptide demonstrates a new method for preparing electrochemical sensors, that are capable of detecting targets in complex biological samples without strong nonspecific protein adsorption.