Effect of PLGA/lecithin hybrid microspheres and β-tricalcium phosphate granules on the physicochemical properties, in vitro degradation and biocompatibility of calcium phosphate cement

To improve the biodegradability and tissue ingrowth of calcium phosphate cement (CPC), poly(lactic-co-glycolic acid)/lecithin (PLGA/Lec) hybrid microspheres and isostatically-pressed high-strength beta-tricalcium phosphate (β-TCP) granules were incorporated into a CPC matrix. The effect on the mechanical properties, setting time, microstructure and morphology of CPC was studied. Then three samples were selected to investigate the influence of the two additives on the biodegradability and biocompatibility of CPC. The results showed PLGA/Lec microspheres reduced the compressive strength of CPC to some extent, but extended the setting time obviously. Based on adding 10 wt% PLGA/Lec microspheres, 10 wt% β-TCP granules enhanced the compressive strength and shortened the setting time of CPC. Furthermore, PLGA/Lec microspheres improved the degradability of the cement and created macropores suitable for cells ingrowth in situ in the process of degradation. Both PLGA/Lec microspheres and β-TCP granules were tested to stimulate the proliferation of mouse bone marrow mesenchymal stem cells (mBMSCs).