Genipin-crosslinked hydrophobical chitosan microspheres and their interactions with bovine serum albumin

In this work chitosan microspheres have been prepared by ion precipitation using sodium sulfate as precipitant, and crosslinked with natural crosslinker genipin. Then the microspheres were hydrophobically modified by covalent and ion interaction grafting of stearic acid and sodium stearate respectively. Results indicated that the there were still some amount of –NH2 groups on the genipin-crosslinked chitosan microspheres. And the contact angles for hydrophobical graft microspheres were increased greatly from 27° to 104°, which indicates stearic chains have been grafted on the surface of the microspheres even only by a simple graft process based on ion interaction. The interactions of protein with the hydrophobically modified chitosan microspheres were investigated by surface absorption method using bovine serum albumin as a model protein. And results indicated that adsorption efficiency for bovine serum albumin of the fatty chain grafted chitosan microspheres was higher than that of the prestine one distinctly, due to the additional hydrophobic interaction. And the adsorbed protein could well-off be desorbed under a general condition.