Enhancing the biological functionality of poly (lactic-co-glycolic acid) cage-like structures through surface modification with micro- and nano-sized hydroxyapatite particles

Biomaterials with exceptional performance are crucial for addressing the challenges of complex bone regeneration. Compared with traditional three-dimensional scaffolds, injectable microspheres enable new strategies for the treatment of irregular bone defects. Biodegradable poly (lactic-co-glycolic acid) has found widespread applications as microcarriers of drugs, proteins, and other active macromolecules. Applied to the surface of poly (lactic-co-glycolic acid) cage-like structures (PLGA-CAS), hydroxyapatite (HA) effectively reduces inflammation while enhancing biological effects. In this study, we loaded the surface of PLGA-CAS with micro- and nano-hydroxyapatite particles, referred to as μHA/PLGA-CAS and nHA/PLGA-CAS, respectively. Subsequently, their material characteristics and biological effects were assessed. The incorporation of hydroxyapatite onto PLGA-CAS resulted in enhanced surface roughness and hydrophilicity, coupled with improved thermal stability and delayed degradation. Furthermore, μHA/PLGA-CAS induced osteogenic differentiation of osteoblast precursor cells, while nHA/PLGA-CAS improved endothelial cell adhesion and stimulated angiogenic differentiation in vitro. Collectively, these findings suggest that μHA/PLGA-CAS and nHA/PLGA-CAS, each with distinct characteristics, hold significant potential for application as microcarriers in various biomedical contexts.