Evaluation of Bone Regeneration by Sustained Release of Bone Morphogenetic Protein from Porous Polyetheretherketone

Owing to its excellent mechanical properties and biocompatibility, polyetheretherketone (PEEK) is a promising biomaterial in dental and medical fields. However, PEEK lacks osteoconductive and osteoinductive properties for efficient bone regeneration. In the present study, we aimed to develop a porous PEEK scaffold integrating gelatin hydrogel as a carrier for the sustained delivery of bone morphogenetic protein-2 (BMP-2) and evaluate its bone regeneration potential. The pores in the three-dimensional printed porous PEEK were filled with an aqueous solution of gelatin, followed by freeze-drying and dehydrothermal crosslinking to obtain a porous PEEK scaffold with gelatin hydrogel (Gel-PEEK). BMP-2 dissolved in phosphate-buffered saline was impregnated into Gel-PEEK to obtain Gel-PEEK incorporating BMP-2 (BMP-2@Gel-PEEK). After confirming the sustained release of BMP-2 from Gel-PEEK in vitro, the bone regeneration potential of BMP-2@Gel-PEEK was evaluated using a model of critical-sized calvarial defects in rats. Micro-computed tomography and histological analyses demonstrated augmented bone regeneration by BMP-2@Gel-PEEK compared with PEEK only and Gel-PEEK without incorporating BMP-2. These findings suggest that through the sustained release of BMP-2, the porous PEEK with gelatin hydrogel is a promising platform for bone regeneration.