An efficient electrochemical biosensor based on double-conductive hydrogel as antifouling interface for ultrasensitive analysis of biomarkers in complex serum medium.

Electrochemical biosensors are suitable for trace detection of biomarkers in serum due to their high sensitivity and fast response time. However, the extensive adsorption of non-specific biomolecules may affect detection results and reduce the operating life of sensors. Herein, an efficient electrochemical biosensor based on double-conductive antifouling hydrogel was developed for ultrasensitive detection of carcinoembryonic antigen (CEA) in serum. Specifically, the antifouling hydrogel was designed with MXene as the conductive framework, and its inherent surface hydrophilicity made it have good antifouling ability. Meanwhile, the introduction of conductive poly(3,4-ethylenedioxythiophene)-poly(styrenesulfonate) further improved the conductivity and stability and of antifouling hydrogel. Furthermore, the prepared MXene nanosheets exhibited large surface area, which could load a large amount of [Ru(NH 3) 6 ]3+ as internal standards. Importantly, the encapsulation of [Ru(NH 3) 6 ]3+ in hydrogel can not only eliminate the environmental and instrument errors, but also realize the integration of antifouling and internal standards, thus simplifying the construction process and improving the detection accuracy of the biosensor. Based on this, the proposed signal "on-off" electrochemical antifouling biosensor realized trace detection of CEA in a wide linear range (1 pg/mL ∼ 1 μg/mL), with a detection limit as low as 0.41 pg/mL (3 δ/k). This study broadens the application of hydrogels in electrochemical antifouling systems, providing a positive reference for sensitive and accurate determination of biomarkers in serum samples. • Developing a double-conductive antifouling hydrogel for electrochemical analysis. • The prepared antifouling hydrogel improves the specificity and operating life of the biosensor. • The integration of antifouling and ratio improves detection sensitivity and accuracy. • The proposed antifouling biosensor is expected to realize trace detection of serum biomarkers. [ABSTRACT FROM AUTHOR]