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) (gamma-PGA) for the sustained delivery of rhBMP-2. Methods: Chitosan and gamma-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/gamma-PGA scaffold (M-o = 318.29 ng, k = 0.32 d (1)) gave the most satisfactory release curve, followed by the freeze-gelled chitosan (M-o = 392.76 ng, k = 0.59 d (1)), freeze-dried chitosan (M-o = 229.21 ng k = 2 28 d (1)), and freeze-dried PLLA (M-o = 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/gamma-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. (c) 2005 Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.