Immobilized trypsin onto chitosan modified monodisperse microspheres: A different way for improving carrier's surface biocompatibility

► The relative activity of immobilized trypsin onto chitosan modified microsphere was higher than that onto no-chitosan grafted microspheres. ► Zeta potential was used to evaluate the immobilization of trypsin. ► The surface biocompatibility of PSt-GMA microspheres is improved suitably for enzyme immobilization.