Preparation of porous chitosan aerogels for efficient adsorption and sustained release of chlorogenic acid via enhanced water permeability

This study aimed to prepare novel chitosan (CS)-based aerogels for efficient loading of hydrophilic chlorogenic acid (CGA) and to facilitate its sustained release in vivo. The mechanical properties and water permeability of the CS-based aerogels were enhanced by incorporating sodium alginate. Melonal sodium alginate CS (MSCS) was synthesised by crosslinking melonal with CS aerogel via a Schiff base reaction. MSCS possesses a three-dimensional porous structure, featuring abundant micropores and mesoporous distributions. Due to the addition of melonal, MSCS demonstrates environmental stability and moisture resistance, with a surface contact angle of 121°. Adsorption capacity tests revealed that MSCS exhibits high adsorption capacity for CGA, reaching 769.4 mg/g, with an adsorption efficiency of 76.94 %. Molecular dynamics simulation results indicate that the adsorption process is exothermic, with increased adsorption capacity at lower temperatures, and is a combination of physical and chemical adsorption. Through quantum chemistry calculations, we identified the adsorption sites of CGA on MSCS and the tendency of MSCS to donate electrons. The in vitro sustained-release experiments demonstrated continuous release of CGA for 48 h in both artificial gastric juice and intestinal fluid, with release rates of 34.26 % and 34.96 %, respectively.