Abstract:

BACKGROUND: Polylactic acid-glycolic acid (PLGA) is a kind of biodegradable polymer with excellent biocompatibility, plasticity and certain strength and toughness. But its degradation products are acidic, which can affect local pH and inhibit tissue growth.
OBJECTIVE: To prepare 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 ionotropic gelation. Ice particulates were used as porogen. Composite scaffolds were prepared with CMs/nHA/PLGA by freeze-drying. Scanning electron microscope, transmission electron microscope, mercury porosimeter and universal testing machine ware used to observe the characteristic and morphology of the composite scaffolds.
RESULTS AND CONCLUSION: The CMs were spherical in shape with a regular surface. The diameters of the CMs were in the range of 220-770 nm, mainly ranging 380-650 nm. The encapsulation efficiency of the CMs was 68.3%, and the loading capacity was 39.2%. The both were related with the initial concentration of BSA. The pore diameter of the composite scaffolds was about 125-355 m, the porosity was 83.4%, and the compressive strength was about 1.4-2.1 MPa. The cumulative degradation was 28.6% at 10 weeks. The cumulative release of BSA from PLGA/nHA scaffolds was 85% in 2 days, which from CMs and CMs/nHA/PLGA scaffolds was 48.9% and 35.7% in 9 days. 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.