A simple strategy for preparation of spherical silica-supported porous chitosan matrix based on sol–gel reaction and simple treatment with ammonia solution

Abstract

A new and effective strategy was proposed for the preparation of an organic-inorganic composite matrix by using spherical silica as a supporting core and porous chitosan (CS) hybrid layer as shell, based on sol–gel reaction and simple treatment with ammonia solution. After metal ion loading, immobilized metal affinity adsorbent for protein adsorption was obtained. In the prepared composite matrix, the coating layer was covalently bonded on the supporting silica through polysaccharide incorporated sol–gel process starting from CS and an inorganic precursor γ-glycidoxypropyltrimethoxysiloxane (GPTMS). This siloxane possessed an epoxide group to cross-link amine groups of CS. Scanning electron microscopy investigation showed that the wet phase inversion of CS in ammonia solution endowed the coated CS hybrid layer with a porous surface. X-Ray diffraction investigation revealed significant decrease of CS crystallization, indicating the availability of active amine groups. The as-prepared matrix was also characterized using simultaneous thermogravimetry and differential scanning calorimetry. After loading Cu²⁺ as pseudo-biospecific ligand, new immobilized metal affinity adsorbent was obtained and its protein adsorption performance was evaluated by batch adsorption experiments using bovine serum albumin (BSA) as a simple model protein. The affinity adsorbent showed fast kinetics and high capability for BSA adsorption. The proposed approach and the prepared matrix showed potential as a platform to conduct bioanalysis.