PREPARATION OF POROUS NANOCOMPOSITE SCAFFOLDS WITH HONEYCOMB MONOLITH STRUCTURE BY ONE PHASE SOLUTION FREEZE-DRYING METHOD

Biodegradable porous nanocomposite scaffolds of poly(lactide-co-glycolide) (PLGA) and L-lactic acid (LAc) oligomer surface-grafted hydroxyapatite nanoparticles (op-HA) with a honeycomb monolith structure were fabricated with the single-phase solution freeze-drying method. The effects of different freezing temperatures on the properties of the scaffolds, such as microstructures, compressive strength, cell penetration and cell proliferation were studied. The highly porous and well interconnected scaffolds with a tunable pore structure were obtained. The effect of different freezing temperature (4 degrees C, -20 degrees C, -80 degrees C and -196 degrees C) was investigated in relation to the scaffold morphology, the porosity varied from 91.2% to 83.0% and the average pore diameter varied from (167.2 +/- 62.6) mu m to (11.9 +/- 4.2) mu m while the sigma(10) increased significantly. The cell proliferation were decreased and associated with the above-mentioned properties. Uniform distribution of op-HA particles and homogeneous roughness of pore wall surfaces were found in the 4 degrees C frozen scaffold. The 4 degrees C frozen scaffold exhibited better cell penetration and increased cell proliferation because of its larger pore size, higher porosity and interconnection. The microstructures described here provide a new approach for the design and fabrication of op-HA/PLGA based scaffold materials with potentially broad applicability for replacement of bone defects.