Graphene Oxide-Regulated Calcium Alginate Molecularly Imprinted Hydrogel Films with Enhanced Physico-Mechanical Properties and Selective Protein Recognition.

Abstract

Calcium alginate (CaAlg) hydrogels are attractive matrices for molecular imprinting because of their biocompatibility and functionalizability, but their limited mechanical stability and excessive swelling can compromise the integrity and accessibility of molecular recognition sites. In this study, graphene oxide (GO) was incorporated into CaAlg to regulate the physicochemical properties of the hydrogel and construct a bovine serum albumin (BSA)-imprinted hydrogel interface for selective protein recognition and electrochemical sensing. The incorporation of GO effectively reduced swelling and enhanced the mechanical stability of the hydrogel, with the 1 wt.% GO-containing film exhibiting a tensile strength of 1921.15 kPa and the highest fracture energy. The resulting molecularly imprinted hydrogel showed a BSA adsorption capacity of 55.21 mg g^-1 and an imprinting efficiency of 3.68, while preferential recognition of BSA over other proteins was observed. After integration with a carbon electrode, template removal and BSA rebinding produced distinguishable electrochemical responses, with an electrochemical imprinting ratio of approximately 6.5. These results demonstrate that GO can simultaneously regulate the structural stability and molecular recognition behavior of CaAlg-based imprinted hydrogels. The proposed hydrogel interface provides a promising material platform for selective protein recognition and electrochemical sensing, with potential applications in biomolecular detection and functional biointerfaces.