Nano‐fibrous microspheres with sustained growth factor delivery for bone regeneration

Abstract

In this study, we developed a unique scaffolding system in which the biodegradable nano‐fibrous microspheres (NF‐MS) serve both as an injectable scaffold and as a growth factor carrier for bone regeneration. The NF‐MS were fabricated by a novel approach, which integrated an emulsification and a thermally induced phase separation technique. The NF‐MS mimicked the architecture of natural collagen fibers at a nanometer scale and had many unique properties including extraordinarily high surface area and extremely low density. Growth factors were effectively encapsulated (>90%) into the NF‐PLLA microspheres through a simple process without using any organic solvent. In vitro release kinetics indicated that the encapsulated recombinant human bone morphogenetic protein 7 (rhBMP‐7) in the NF‐MS were released in a temporal controlled manner. When used as an injectable scaffold for repairing the rat critical‐size calvarial defects, the rhBMP‐7‐loaded NF‐MS induced a much more significant amount of new bone formation than the rhBMP‐7‐free NF‐MS control. We conclude that the nano‐fibrous architecture combined with the sustained release of bioactive rhBMP‐7 from the NF‐MS are excellent cell carrier for bone regeneration. Support: NIH5P30DE20742Grant Funding Source: NIH 5P30DE20742