title: In vitro and in vivo release of vascular endothelial growth factor from gelatin microparticles and biodegradable composite scaffolds.
abstract: OBJECTIVE
  This work evaluated gelatin microparticles and biodegradable composite scaffolds for the controlled release of vascular endothelial growth factor (VEGF) in vitro and in vivo.
  
  
  METHODS
  Gelatin crosslinking, VEGF dose, and buffer type were investigated for their effects on VEGF release. Release was also evaluated from microparticles confined within porous polymer scaffolds (composites). In vitro and in vivo studies were conducted using radiolabeled VEGF.
  
  
  RESULTS
  The effect of VEGF dose on its fractional release from gelatin microparticles in vitro was minimal, but the addition of collagenase to the buffer resulted in a higher cumulative release of VEGF. Gelatin crosslinking extent was a significant factor on release from both microparticles alone and composite scaffolds in vitro and in vivo. VEGF bioactivity from composite scaffolds in vitro was maintained above 90% of the expected bioactivity over 14 days.
  
  
  CONCLUSIONS
  VEGF release kinetics were dependent on the extent of gelatin crosslinking and were characteristic of the specific growth factor due to the effects of growth factor size, charge, and conformation on its complexation with gelatin. These studies demonstrate the utility of gelatin microparticles and their composite scaffolds as delivery vehicles for the controlled release of VEGF for tissue engineering applications.
authors.affiliation: Department of Bioengineering, Rice University, P.O. Box 1892, MS-142, Houston, Texas 77251-1892, USA.
authors.forename: Zarana S
authors.initials: ZS
authors.lastname: Patel
authors.forename: Hiroki
authors.initials: H
authors.lastname: Ueda
authors.forename: Masaya
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Yasuhiko
authors.initials: Y
authors.lastname: Tabata
authors.forename: Antonios G
authors.initials: AG
authors.lastname: Mikos
mesh_terms: D043925:Angiogenesis Inducing Agents / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology; D000818:Animals; D002021:Buffers; D049109:Cell Proliferation / Q000187:drug effects; D002478:Cells, Cultured; D002626:Chemistry, Pharmaceutical; D003432:Cross-Linking Reagents / Q000737:chemistry; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D042783:Endothelial Cells / Q000187:drug effects; D005260:Female; D005780:Gelatin / Q000737:chemistry* / Q000378:metabolism; D005976:Glutaral / Q000737:chemistry; D006801:Humans; D006863:Hydrogen-Ion Concentration; D007700:Kinetics; D051379:Mice; D010316:Particle Size; D011108:Polymers; D016062:Porosity; D012995:Solubility; D013499:Surface Properties; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry*; D042461:Vascular Endothelial Growth Factor A / Q000737:chemistry / Q000378:metabolism* / Q000494:pharmacology
chemical_list: D043925:Angiogenesis Inducing Agents; D002021:Buffers; D003432:Cross-Linking Reagents; D003692:Delayed-Action Preparations; D004337:Drug Carriers; D011108:Polymers; D042461:Vascular Endothelial Growth Factor A; D005780:Gelatin; D005976:Glutaral