PLLA grafting draws GO from PGA phase to the interface in PLLA/PGA bone scaffold owing enhanced interfacial interaction

The interfacial interaction between poly (l-lactic acid) (PLLA) and poly (glycolic acid) (PGA) is poor although the blending of PLLA and PGA may combine the advantages of both, which seriously affects the mechanical properties of PLLA/PGA bone scaffold. In this study, PLLA chains were grafted onto graphene oxide (GO) by ring-opening polymerization reaction, and the modified GO was used as nanofiller to increase the interfacial interaction for PLLA/PGA scaffold fabricated by selective laser sintering (SLS). The result indicated that GO grafted with PLLA chains reduced the interfacial tension between GO and PLLA from 24.09 mN/m to 3.74 mN/m, thus drawing GO from PGA phase to the interface between PLLA and PGA. The GO at the interface hindered the coalescence of PGA phase through the repulsive forces and facilitated the breakup of the PGA phase, which increased the contact surface area between PLLA and PGA, and thereby enhancing the interfacial interaction. Consequently, the tensile and compressive strength of the PLLA/PGA scaffold containing 1 wt% the PLLA-grafted GO, on which L-LA ring-opening polymerized for 24 h, were increased by 44.64% and 69.65%, respectively, compared with PLLA/PGA scaffold. Besides, the cell adhesion and fluorescence experiments demonstrated that the bone scaffold had good cytocompatibility for cell adhesion, migration and proliferation.