Mineral tourmaline nanoparticles modifying surface performances of hydroxyapatite/poly(L-lactide-co-caprolactone) 3D-printed scaffold for accelerated bone regeneration

Biodegradable polymer matrix scaffold is a promising design for large-scale bone regeneration, but its accelerated osteogenesis remains a challenging issue in clinical practice. Due to special crystal structure, natural mineral tourmaline has the characteristics of spontaneous polarization, which is potential to provide a pro-regenerative microenvironment in bone tissue engineering. This study is aimed to develop tourmaline-ameliorated hydroxyapatite/poly( L -lactide- co -caprolactone) (TM/HA/PLCL) scaffolds with prompted osteogenic activity through regulating surface performances. HA/PLCL scaffolds with different amounts of TM nanoparticles are prepared by 3D-printing technology, with uniform morphology and desired mechanical property in the range of bone trabeculae. The assessments confirm that TM nanoparticles addition modulate surface potential and hydrophilicity of HA/PLCL scaffold to improve the apatite mineralization and osteogenic differentiation ability. In vitro biological experiments, all composite scaffolds conform to the standard requirements, 10%TM/HA/PLCL is less cytotoxic and more prone to promote the MC3T3-E1 cells activity, whose viable cells increase by about 42% and expression of osteogenic-related genes is more remarkable. Furthermore, in vivo study of repairing rat cranial defects, 10%TM/HA/PLCL scaffold accelerates new bone formation. The results suggest this composite scaffold with modified surface performances by mineral TM is an attractive strategy in artificial bone repair.