Label-free electrochemical biosensor based on AuNPs and PCL-b-PHEAA amphiphilic copolymer for highly sensitive detection of CEA

Abstract

Carcinoembryonic antigen (CEA) is a broad-spectrum tumor marker expressed in various human cancers. In this study, the electrode loaded with AuNPs was used to replace the traditional electrode, providing more active sites for biological probes and significantly enhancing the sensitivity of the sensor. By constructing an aptamer-antigen-aptamer "sandwich structure," highly selective detection was achieved, effectively avoiding cross-reactions. In addition, the polymer PCL-b-PHEAA was introduced for signal amplification, further improving the detection performance. The label-free method directly utilizes the biological recognition system to obtain more accurate information and is more convenient to operate. Under the optimal conditions, the linear range of CEA detection by electrochemical impedance method was 100 fg mL^-1 - 200 ng mL^-1, and the limit of detection was 60 fg mL^-1. Moreover, this approach demonstrates remarkable sensitivity and exceptional anti-interference capabilities when applied to the analysis of clinical samples. As such, it presents a far more efficient and precise detection solution for the biosensing domain.

Keywords: Amphiphilic copolymers; AuNPs; Biosensors; Carcinoembryonic antigen; Electrochemical impedance spectroscopy.