Mechanical and rheological properties and injectability of calcium phosphate cement containing poly (lactic-co-glycolic acid) microspheres

To enhance tissue ingrowth and promote rapid resorption, efforts were made to build macropores into calcium phosphate cement (CPC); however, this led to a decrease in its mechanical properties. In this study, poly (lactic-co-glycolic acid) (PLGA) microspheres were incorporated into CPC to impart macroporosity and maintain early strength. The influences of the content of PLGA microspheres on the mechanical strength, rheological properties, injectability, setting time, and microstructure of CPC were also systematically investigated. At the PLGA to CPC mass ratios of 20/80 and 30/70, the compressive strength of the composites was similar to that of CPC without PLGA microspheres. The rheological results indicated that PLGA microspheres/CPC pastes showed plastic and shear-thinning behaviors. The addition of PLGA microspheres to CPC resulted in the increase of viscosity and yield stress of the pastes. Simultaneously, the injectability of the pastes decreased with the addition of PLGA microspheres. When the PLGA to CPC ratio was 20/80, the injectability of the paste was still higher than 95%. The calcium phosphate cement containing 20 wt.% PLGA microspheres exhibited excellent injectability and satisfactory setting time without strength degradation. Obviously, such an in situ macropores-generable CPC should have potential prospects for the wider applications in orthopedics, oral, and maxillofacial surgery.