Protein imprinted CaAlg/CaSiO3 hybrid hydrogel modified electrochemical sensor for sensitive detection of BSA

Abstract

Hydrogels showed superiorities in molecularly imprinting sensors for detecting biomolecules owing to their stimulus-responsive nature. However, the excessive swelling of hydrogel during the elution process damages the imprinting cavities, leading to a reduction in sensitivity. In this study, a molecularly imprinted electrochemical sensor was designed for rapid protein recognition. The sensor utilized a composite hydrogel based on hybrid cross-linked calcium alginate/calcium silicate (CaAlg/CaSiO₃) to mitigate the excessive swelling of the CaAlg hydrogel. The preparation involved coating a bare carbon electrode with a sodium silicate-sodium alginate (Na₂SiO₃-NaAlg) mixed solution, cross-linking with CaCl₂ solution, and eluting bovine serum albumin (BSA) with Tris-HCl solution. The incorporation of CaSiO₃ nanoparticles stabilized the organic-inorganic hybrid structure, enhancing the hydrogel's resistance to swelling and maintaining cavity integrity. The molecularly imprinted polymer (MIP) sensor demonstrated high selectivity for BSA, excellent repeatability, long-term stability, and reproducibility, showing the potential for improved sensitivity in biomolecule detection.