Synergistic Effect of Porous Hydroxyapatite Scaffolds Combined with Bioactive Glass/Poly(lactic-co-glycolic acid) Composite Fibers Promotes Osteogenic Activity and Bioactivity

Porous hydroxyapatite (HAp) scaffolds are commonly used for hard tissue regeneration because of their biocompatibility and osteoconduction properties, but they are limited in terms of bioactivity and osteoinduction. This study investigated the fabrication of HAp scaffolds coated with poly(lactic-co-glycolic acid)/45S5 bioactive glass (PLGA/BG) composite microfibers using the sponge replica method and electrospinning process for improved bioactivity and osteoinductivity during osteogenesis. Characterization of the HAp/PLGA/BG (HPB) scaffold was carried out by examining morphology and ion release. The biological evaluation of HPB scaffolds was carried out by assessing cytotoxicity, cell proliferation, and cell differentiation using MC3T3-E1 preosteoblasts. The results showed that all HPB scaffolds exhibited a high porosity of 89.2% and had porous structures coated with a layer of composite containing BG ions (Si-Ca-Na-P). These scaffolds enabled controlled release of Si, Ca, Na, and P ions for up to 28 days. There was no significant difference in cytotoxicity between the scaffolds. Cell proliferation on HPB scaffolds was increased from day 1 to 3. In addition, cell viability on the HPB scaffolds was confirmed with LIVE/DEAD assay. Cell differentiation, as shown by alkaline phosphatase activity and western blot analyses, indicated that HPB scaffolds with 20 and 30 min of coating induced higher levels of osteogenesis-related markers compared to other scaffolds. Furthermore, immunocytochemistry indicated osteopontin expression. Alizarin red staining indicated that HPB scaffolds with 20 min of coating were more effective than the HAp scaffold in terms of mineralization. In conclusion, HAp scaffolds coated with PLGA/BG for 20 min are promising materials for osteogenic activity and may be a potential bone substitute for tissue engineering.