Design, fabrication and biocompatibility of 3D printed poly (LLA-ran-PDO-ran-GA)/poly(D-lactide) composite scaffolds for bone tissue engineering

The long-term nonunion of bone defects remains a significant challenge in the field of orthopedics. Poly(L-lactic acid) (PLLA), widely used in bone tissue engineering, offers hope for addressing this issue. In our previous study, we aimed to enhance the poor toughness and slow degradation of PLLA by introducing flexible p-dioxanone (PDO) and highly reactive glycolide (GA) units into the molecular chain of PLLA to prepare PLLA-ran-PDO-ran-GA (PLPG) scaffolds, effectively mitigating the limitations of PLLA. However, the crystallization capacity of PLPG copolymers was weakened, resulting in insufficient mechanical properties. Therefore, in this study, poly(D-lactic acid) (PDLA) was introduced into PLPG via solution blending to enhance its crystallization properties through the in situ generation of stereocomplex poly(lactic acid) (SC-PLA). Subsequently, PLPG/PDLA scaffolds were prepared using 3D printing technology. The results demonstrated that PLPG/PDLA composites exhibited good machinability, while the scaffolds showed satisfactory mechanical and degradation properties. Additionally, cell experiments indicated that PLPG/PDLA scaffolds possess biocompatibility, allowing for cell growth and proliferation on their surfaces. We believe that PLPG/PDLA scaffolds have significant potential for application in bone tissue engineering, effectively addressing the issue of long-term non-healing bone defects.