3D printing of polylactic acid/boron nitride bone scaffolds: Mechanical properties, biomineralization ability and cell responses

Polylactic acid (PLA) has been widely utilized as a bone scaffold material; however, it exhibits inadequate mechanical performance, biomineralization ability, and cell response, leading to limitations in its practical application. In this study, we utilized boron nitride (BN) nanosheets with favorable mechanical and biological properties to improve the performances of PLA, and prepared PLA/BN composite scaffolds by FDM 3D printing technology. Then, the PLA/BN composite scaffolds with varying BN contents (0–4 wt%) were investigated in terms of microstructure, mechanical performance, biomineralization ability, and cell response. The results showed that the FDM printed PLA/BN scaffolds have an orderly and interconnected porous structure. The mechanical tests showed that the tensile and compression properties (strength and modulus) increased first and then decreased with the content of BN gradually increasing from 0 wt% to 4 wt%, with the optimum mechanical properties occurring at 1 wt%, as an appropriate content of BN could be well-dispersed in the PLA matrix with forming a good interfacial bond, while an excessive content of BN would lead to obvious agglomeration. The simulated body fluid (SBF) soaking experiments showed that BN improved the biomineralization of the PLA scaffold through promoting the formation and deposition of apatite on the scaffold surface by accelerating ion exchange. Besides, an appropriate content of BN promoted the adhesion, proliferation, and osteogenic differentiation of rabbit bone marrow mesenchymal stem cells (BMSCs). These results indicated that BN could be used as a versatile filler for improving the comprehensive performances of polymers, especially for bone tissue engineering.