Effect of nano-hydroxyapatite on protein adsorption and cell adhesion of poly(lactic acid)/nano-hydroxyapatite composite microspheres

Surface properties of biomaterials are significant as they are intended to interact with biological system interfaces. This study was aimed to reveal the effect of nano-hydroxyapatite (Nano-HAP) on the properties of poly(lactic acid) (PLA) microspheres. Nano-HAP particles of 10–30% content were successfully embedded in PLA microspheres by emulsion solvent evaporation method. The incorporation of Nano-HAP particles resulted in the increases of surface hydrophilicity and surface rough of microspheres that depended on the content of Nano-HAP. With the increase of Nano-HAP content, the adsorption capacity for protein of PLA/Nano-HAP composite microspheres was increased significantly. Moreover, the incorporation of Nano-HAP could promote the adhesion and proliferation of rat Mesenchymal Stem cells (rMSCs) on microspheres, which could be attributed to the component of Nano-HAP as well as the increases of surface hydrophilicity and rough. In addition, PLA/Nano-HAP composite microspheres showed significant promotion on osteogenic differentiation of rMSCs due to the facilitation of Nano-HAP. Accordingly, the incorporation of Nano-HAP could improve the physicochemical and biological properties of PLA microspheres, and the resulting PLA/Nano-HAP composite microspheres could be expected to achieve good application in tissue repair.