Preparation And Properties Of Chitosan-based Protein Immobilization Carrier

In this study, glutaraldehyde-acetic acid crosslinking-swelling method, sodium tripolyphosphoric single coacervation method and sodium alginate double coacervation method were used to fabricate the protein carrier based on chitosan, BSA immobilization in the carriers was studied respectively. The shape and surface feature of the carriers were observed by means of optical microscopy (OM), scanning electron microscopy (SEM) and transmission electron microscopy (TEM), the diameter, FTIR, entrapment efficiency, loading efficiency and vitro release behavior were further studied. The outcome distilling, protein activity remaining and entrapment efficiency were used to compare the three methods. FITC-BSA was used as a model protein to explore the permeability of the microcapsule membrane which was fabricated by the double coacervation method.It was showed that all of the carriers could immobilize the BSA. The entrapment efficiency of the carrier which was fabricated by the glutaraldehyde-acetic acid crosslinking-swelling method changed from 10% to 40%, but the protein activity might be influenced by the leaving glutaraldehyde; the entrapment efficiency of the carrier which was fabricated by the sodium tripolyphosphoric single coacervation method changed from 20% to 30%, however, the outcome was not easily distilled; the entrapment efficiency of the carrier which was fabricated by sodium alginate double coacervation method was higher than that of the former carriers, the entrapment efficiency could reached to 85.37% by optimize the experiment conditions, furthermore, the organic solvent was not used, the fabrication condition was mild and the outcome was easily distilled, so the sodium alginate double coacervation method was adapted to fabricate the protein immobilization carrier.Research in the Protein permeability of the microcapsules which were fabricated by sodium alginate double coacervation method showed that the microcapsules presented a volume phase transition feature that protein permeability of the microcapsules decreases when pH was 1.5 to 2.0, whereas increased when pH was 6.8. The permeability of the calcium alginate microcapsules was better than that of the calcium alginate-chitosan microcapsules, and in the calcium alginate-chitosan microcapsules the lower the concentration of chitosan was, the higher the permeability was. The effect of the concentration of alginate was not obvious.The carrier which was fabricated by sodium alginate double coacervation method was used to research the immobilization of thrombin. The results showed that the microcapsule could immobilize the thrombin. The result of dynamic cruor experiment showed that the entrapment of this microcapsule was high, the effect of immobilization and the activity remaining of thrombin were good; the result of biocompatibility study showed that the microcapsule could cause slight inflammation reaction, the inflammation reaction was obvious after implantation in one week, the degree of inflammation reaction decreased gradually.