A novel ternary polymer/β-TCP composite microspheres with polydopamine-encapsulated nano zinc oxide coating for bone tissue engineering

Addressing the prevalent clinical issue of bone defects, this study successfully developed a novel ternary copolymer material (PLCD) based on polylactic acid (PLA), polycaprolactone (PCL), and polydioxanone (PPDO). This ternary material combines the strength of PLA, the toughness of PCL, and the controllable rapid degradation properties of PPDO. making it a promising candidate for biomedical applications. By using an optimized emulsion method combined with finite element analysis, microspheres with a particle size range of 500–700 μm were prepared and subsequently fabricated into microsphere scaffolds using the solvent sintering method. To enhance osteoinductive and osseointegration capabilities, various proportions of β-tricalcium phosphate (β-TCP) were uniformly dispersed within the microspheres, creating composite scaffolds. Additionally, nano zinc oxide were coated on the microsphere scaffold surface using the in situ polymerization properties of dopamine, imparting antibacterial properties and enhancing functionality. Physical and biological evaluations of the microsphere scaffolds revealed excellent overall performance, including an interconnected porous structure, porosity and mechanical properties matching those of cancellous bone, suitable degradation behavior, and in vitro mineralization ability. Furthermore, scaffolds coated with polydopamine and loaded with nano zinc oxide exhibited strong initial antibacterial effects, and promoted osteogenic differentiation. These results indicate that the developed composite microsphere scaffolds have significant potential in bone tissue engineering applications, offering a promising solution for effective bone regeneration.