Electrochemical Biosensors Capable of Detecting Biomarkers in Human Serum with Unique Long-Term Antifouling Abilities Based on Designed Multifunctional Peptides.

An electrochemical sensing platform for biomarker detection in complex serum samples with unique long-term antifouling performance was constructed, based on newly designed multifunctional peptides containing anchoring, doping, linking, and antifouling sequences. The designed peptides were first attached onto an electrode surface with the assistance of the anchoring sequences, and the negatively charged doping sequences as dopants for conducting polymer poly(3,4-ethylenedioxythiophene) (PEDOT) were then precisely doped into the electropolymerized PEDOT to form a conducting and stable substrate, leaving the linking and antifouling sequences exposed on the PEDOT substrate surface. The linking sequence of the peptide between the doping and antifouling parts was designed to be beneficial for enhancing the antifouling performance. After the biorecognizing probe immobilization, the obtained biosensor was able to detect targets with a low limit of detection of 2.3 fM and high specificity in complex biological fluids. More importantly, the electrochemical biosensor exhibited incomparable long-term antifouling performances over previous reports and retained their antifouling capabilities for 20 days, indicating a promising feasibility of this design strategy for the construction of biosensors and bioelectronics to be used or implanted in real biological systems.