The design, fabrication and evaluation of 3D printed gHNTs/gMgO whiskers/PLLA composite scaffold with honeycomb microstructure for bone tissue engineering

To achieve 3D printing scaffolds for bone tissue repairing, suitable consumables are the prerequisite requirement. However, though various bone repair scaffolds were prepared, there were few clinical applications owing to their poor mechanical performances and limited osteogenic activity. In this study, a novel 3D printing composite consumable consisting of poly (L-lactide) (PLLA) matrix, surface grafted MgO whiskers (gMgOs) and halloysite nanotubes (gHNTs) was developed. This design can fully combine the printability of PLLA, the excellent osteogenic activity of gMgOs and the outstanding reinforcement and toughening effect of gHNTs. Using such consumables, the porous gHNTs/gMgOs/PLLA composite scaffolds with large and small pores and honeycomb structure were further fabricated by 3D printing. The synergetic presence of gMgOs and gHNTs can endow the as-prepared composite scaffolds with obviously enhanced hydrophilicity, tensile and compressive properties, as well as cell affinity and osteogenic activity. Moreover, gMgOs and gHNTs play different roles in improving the performance of the composite scaffold. The gHNTs can effectively improve the mechanical properties of the scaffolds, while the gMgOs were more beneficial to mouse embryo osteoblast precursor (MC3T3-E1) cells adhesion, proliferation, migration and secretion of ALP activity and calcium depositions on the scaffolds.