Fabrication and release behavior of a novel freeze-gelled chitosan/γ-PGA scaffold as a carrier for rhBMP-2

Objective The aim of this study was to fabricate a novel composite porous scaffold by blending chitosan and gamma-poly(glutamic acid) (γ-PGA) for the sustained delivery of rhBMP-2. Methods Chitosan and γ-PGA were blended to fabricate a novel porous scaffold by the freeze-gelation method. For comparison, scaffolds made of freeze-dried chitosan, freeze-dried PLLA, and freeze-gelled chitosan were also prepared. The scaffolds were loaded with rhBMP-2, and then the controlled release of rhBMP-2 from the scaffolds was assessed by ELISA. Results The freeze-gelled chitosan/γ-PGA scaffold (M0=318.29 ng, k=0.32 d−1) gave the most satisfactory release curve, followed by the freeze-gelled chitosan (M0=392.76 ng, k=0.59 d−1), freeze-dried chitosan (M0=229.21 ng, k=2.28 d−1), and freeze-dried PLLA (M0=8.4 ng, k=482.54 d−1) scaffolds. In the stability test, p-dioxane (the solvent for PLLA) seriously deteriorated rhBMP-2, whereas acetic acid (the solvent for chitosan) did not. Significance A novel chitosan/γ-PGA composite scaffold for the controlled release of rhBMP-2 was established, with an enhanced release amount and sustained release behavior. This scaffold has many potential applications in bone regenerative therapies.