Prostate specific antigen quantification in human serum supported by the designed four-in-one octabranched peptides and AgNPs-based signal amplifier

Abstract

BackgrounIt remains challenging for biosensors to directly detect clinical targets in complex biological media with high selectivity and low fouling. MethodsHerein, an antifouling and ultrasensitive biosensor supported by the designed four-in-one octabranched peptides and signaling amplification strategy of silver nanoparticles (AgNPs) was constructed for prostate specific antigen (PSA) quantification in human serum. Chondroitin sulfate functionalized polyaniline (PANI) nanowires and gold nanoparticles (AuNPs) were electrodeposited onto the electrode in sequence to promote electrons transport, and followed by the attachment of the designed octabranched peptides. Significant findingsThe peptides were specially designed to contain four structural domains, namely anchoring domain (CC), linking domain (PPPP), antifouling domain (EKEKEKE), and recognition domain (HSSKLQK). AgNPs loaded on graphene oxide were assembled onto peptides as a signal amplification strategy. The peptides were specifically sheared off by PSA, resulting in a significantly reduced electrochemical response that can be used to sensitively indicate PSA concentration. The antifouling biosensor exhibited a linear response range from 1 × 10−14 to 1 × 10−6 M, with a low detection limit of 1.33 × 10−15 M. Furthermore, the biosensor was employed to detect PSA in clinical samples based on the four-in-one octabranched peptides, indicating feasibility of the biosensor for early clinical diagnosis.