Polydopamine modified polycaprolactone powder for fabrication bone scaffold owing intrinsic bioactivity

Polycaprolactone (PCL) has been extensively investigated in the field of bone tissue engineering due to its good biocompatibility, biodegradability and processability. Nevertheless, the lack of bioactivity results in poor osseointegration between artificial implant and host bone tissue, which severely restricts its application for bone regeneration. In this study, PCL powder was first surface functionalized with polydopamine (PDA) coating through oxidative self-polymerization of monomer dopamine, and the PDA modified PCL powder was used for the fabrication of bone scaffold with intrinsic bioactivity via selective laser sintering (SLS). The results suggested that PDA was modified on the PCL powder surface successfully and still remained after laser sintering. The 3D printed scaffold achieved a transition from bioinert to bioactive as evaluated by the formation of apatite on its surface, which was the result of the interaction between the abundant active catechol groups in the introduced PDA and calcium ion from simulated body fluid. Besides, the scaffold provided more hydrophilic surfaces for cell adhesion and growth than the pure PCL scaffold due to the presence of amino and hydroxyl functional group.