Porous hydroxyapatite scaffolds containing dual microspheres based on poly(lactide-co-glycolide) and chitosan for bone regeneration

Abstract The strategy of incorporating both scaffold and drug delivery systems to promote tissue growth, has attracted increasing attention in the field of bone tissue engineering. The aim of this study was to incorporate dual microspheres with different diameters, based on chitosan (CS) and poly(lactide-co-glycolide) (PLGA), onto the porous surface of hydroxyapatite scaffolds (HAs). The scaffolds and microspheres were prepared by the sphere-leaching method and emulsion technique, respectively. Through electrostatic interactions, the CS and PLGA microspheres were successfully immobilized onto the porous surface of alginate-precoated HAs. The CS microspheres were homogeneously and solidly immobilized onto the surface of the HAs, whereas the PLGA microspheres were attached to the surface of the CS microspheres. Additionally, the compressive strength of the scaffolds was obviously improved by the alginate coating. Such HAs combined with two types of microspheres to build a dual delivery system would be a promising and suitable vehicle for the repair of bone tissue defects.