In vitro and long‐term (2‐year follow‐up) in vivo osteogenic activities of human periosteum‐derived osteoblasts seeded into growth factor‐releasing polycaprolactone/pluronic F127 beads scaffolds

Polycaprolactone (PCL) is a biodegradable polyester that is bioresorbable and biocompatible, and is widely used in medical fields. This study examines in vitro and in vivo osteogenic activities of cultured human periosteum‐derived osteoblasts (POs) seeded into growth factor (bone morphogenic protein 2 [BMP‐2] or vascular endothelial growth factor [VEGF])‐releasing scaffolds of PCL beads coated with Pluronic F127. Each growth factor immobilized in the PCL/F127 is cumulatively released from the beads for more than 40 days (up to 3.04 ± 0.08 ng mg−1 BMP‐2 and 3.41 ± 0.18 ng mg−1 VEGF in 42 days). Long‐term (∼2 years) experimental results obtained in a miniature pig model suggest that POs seeded into BMP‐2 + VEGF‐releasing PCL/P‐F127 beads are the most effective for bone repair. In in vitro assays, osteogenic activities were higher in POs seeded into BMP‐2‐releasing PCL/Pluronic F127 beads at earlier time points and in POs seeded into BMP‐2 + VEGF‐releasing PCL/Pluronic F127 beads at later time points. These results suggest that the combination of BMP‐2 and VEGF more sufficiently stimulates (in particular at late time points) osteoblast differentiation of POs seeded in the PCL/F127 in vitro and in vivo, and thus allows effective bone regeneration. © 2016 Wiley Periodicals, Inc. J Biomed Mater Res Part A: 105A: 363–376, 2017.