A Superb Antifouling Electrochemical Biosensor Based on Macrocycle Encapsulation Strategy for Biomarker Analysis in Complex Biofluids.

Abstract

Conquering microenvironmental interferences and achieving high sensing performance are challenging in biomarker analysis within complex biological fluids due to electrode biofouling and enzymatic degradation. Herein, a robust sensing interface was developed via a host-guest interaction strategy, where a peptide recognition unit (specific for Furin protein in this study) was encapsulated by a giant macrocycle to enhance antifouling and proteolytic resistance. The peptide could be effectively complexed with the designed large-sized water-soluble quaterphen[4]arene sulfate (WQP[4]S) through host-guest molecular recognition to resist protease hydrolysis and improve the stability of the peptide. At the same time, the complex formed by WQP[4]S and the peptide demonstrated high water solubility and electrical neutrality, thus providing an excellent antifouling performance for the sensing interface. In addition, methylene blue (MB) was introduced as an inter-reference molecule to develop a ratiometric electrochemical biosensor for highly accurate analysis. The WQP[4]S-modified peptide-based biosensor exhibited high selectivity and sensitivity for precise Furin detection and achieved a low detection limit of 0.81 U L-1, and it assayed Furin targets accurately in blood samples from both healthy individuals and patients with diabetes. This study presents a novel and effective approach to develop antifouling and enzymatic-resistant biosensors for precise biomarker detection in complex biological fluids.