Abstract
Desirably porous biodegradable hybrid composite microspheres were fabricated for use in bone graft and bone substitute applications. In this study, novel poly(ε‐caprolactone)/biphasic calcium phosphate (70/30) composite microspheres (PCL/BCP MPs) were prepared using the emulsion solvent‐evaporation method. Throughout this process, the ammonium bicarbonate (NH~4~HCO~3~) content was changed to obtain the desired porous structure. However, to maintain the spherical shape, the NH~4~HCO~3~ content should not be higher than 5%. In the optical images of the PCL/BCP MPs, almost all the microparticles had a spherical shape, and the average diameter was about 600 μm. The scanning electron microscopy and cross‐sectional optical images showed that the pore density and pore diameter of PCL/BCP MPs increased with increasing initial NH~4~HCO~3~ concentrations. In the phase‐composition analysis of the PCL/BCP MPs, which was characterized by X‐ray diffraction and EDS, the two crystals BCP and PCL phases were shown to be miscible in PCL/BCP MPs. When the degradation of these microspheres was characterized, PCL/BCP MPs‐0, PCL/BCP MPs‐2, and PCL/BCP MPs‐5 were found to display a sustained biodegradability, and the rate of degradation increased at higher initial NH~4~HCO~3~ concentrations. Proliferation of cells on three different sample types was assessed and compared, and based on these results, the PCL/BCP MPs‐5 was chosen to study MG‐63 osteoblast‐cell adhesion, growth, and proliferation. Furthermore, confocal images indicated that the cells effectively adhered, spread, and proliferated on PCL/BCP MPs‐5 during a 5‐day culture period. © 2011 Wiley Periodicals, Inc. J Biomed Mater Res Part B: Appl Biomater, 2011.