An antifouling electrochemical biosensor based on chitosan and DNA dual-network hydrogel for ATP quantification in complex biofluids

Abstract

Adenosine triphosphate (ATP) plays a crucial role in energy conduction, cellular respiration, and signal transduction, and its level is highly related to the human health status. However, the detection of ATP in complex biological fluids such as serum with electrochemical sensors remains a great challenge due to the severe biofouling. Inspiring by the layered micro-nano structures of biological surfaces such as rose petal and water strider, we herein construct a robust electrochemical biosensor for ATP assaying in human serum based on a composite hydrogel with a network microstructure. Chitosan hydrogel and DNA hydrogel were combined to form a dual network structure and modified on the electrode surface, which can effectively enlarge the surface area and hydrophilicity of the modified electrode surface. Meanwhile, abundant aptamers were immobilized on the porous hydrogel surface to specifically recognize ATP molecules. The electrochemical biosensor possessed ATP recognition and antifouling capability, and it exhibited a linear range from 0.1 pM to 1 μM for ATP detection, with a remarkably low limit of detection of 0.033 pM. Moreover, the biosensor was capable of determining ATP levels in human sera and cell lysates with satisfying accuracy comparable to the ELISA kits. This strategy for antifouling biosensor construction holds great potential for biomarker detection in complex biofluids and clinical diagnosis.