The Preparation And Releasing Behavior Of Compound Chitosan Nano-microspheres PLGA/nHA Control-releasing Carrier

Objective:To preparation composite scaffolds with excellent characteristics of delayed release of proteins. Methods Using Bovine serum album (BSA) as model protein, chitosan microspheres (CMs) were prepared by inotropic gelation. Ice particulates was used as porogen. Composite scaffolds were prepared with CMs/nHA/PLGA by freeze-drying. Scanning electron microscope (SEM), transmission electron microscope, mercury porosimeter and universal testing machine ware used to observed the characteristic and morphology of the composite scaffolds. Results The CMs were spherical in shape with a regular surface. The diameters of the CMs were in the range of 400-600nm. The encapsulation efficiency of the CMs was 62%, and the loading capacity was 39%. The both were related with the initial concentration of BSA. The pore diameter of the composite scaffolds was about 125～355μm, the porosity was over 80%, and the compressive strength was about 1.4～2.4 MPa. The cumulative degradation was 28.6% at 10 weeks. The cumulative release of BSA from PLGA/nHA scaffolds was above 80% at 48 hours, which from CMs was 48.9% on 9 days, while that from CMs/nHA/PLGA scaffolds was 35.7% on 9 days. Conclusion The CMs microspheres and CMs/nHA/PLGA scaffolds have a desirable release rates for BSA and strength, are expected to use as carrier for growth factor and bone tissue engineering scaffolds.