title: Fabrication and release behavior of a novel freeze-gelled chitosan/gamma-PGA scaffold as a carrier for rhBMP-2.
abstract: 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 (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.
  
  
  CONCLUSIONS
  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.
authors.affiliation: Department of Chemical Engineering, National Taiwan University, Taipei, Taiwan, ROC.
authors.forename: Chieh-Yang
authors.initials: CY
authors.lastname: Hsieh
authors.forename: Hsyue-Jen
authors.initials: HJ
authors.lastname: Hsieh
authors.forename: Hwa-Chuang
authors.initials: HC
authors.lastname: Liu
authors.forename: Da-Ming
authors.initials: DM
authors.lastname: Wang
authors.forename: Lein-Tuan
authors.initials: LT
authors.lastname: Hou
mesh_terms: D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000008:administration & dosage* / Q000737:chemistry; D048271:Chitosan; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D004355:Drug Stability; D005612:Freeze Drying; D005782:Gels; D006801:Humans; D008855:Microscopy, Electron, Scanning; D011099:Polyglutamic Acid; D011994:Recombinant Proteins / Q000008:administration & dosage; D012997:Solvents; D016212:Transforming Growth Factor beta / Q000008:administration & dosage* / Q000737:chemistry
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D005782:Gels; D011994:Recombinant Proteins; D012997:Solvents; D016212:Transforming Growth Factor beta; D011099:Polyglutamic Acid; D048271:Chitosan