title: Controlled release of growth factors based on biodegradation of gelatin hydrogel.
abstract: To develop a carrier for the controlled release of biologically-active growth factors, biodegradable hydrogels were prepared through glutaraldehyde cross-linking of gelatin with isoelectric points (IEP) of 5.0 and 9.0, i.e. 'acidic' and 'basic' gelatins, respectively. Radioiodinated growth factors were used to investigate their sorption and desorption from the hydrogel of both types of gelatin. Basic fibroblast growth factor (bFGF) and transforming growth factor-beta1 (TGF-beta1) were well sorbed with time to the acidic gelatin hydrogel, while less sorption was observed for the basic gelatin hydrogel. This could be explained in terms of the electrostatic interaction between the growth factors and the acidic gelatin. However, bone morphogenetic protein-2 (BMP-2) and vascular endothelial growth factor (VEGF), though their IEPs are higher than 7.0, were sorbed to the acidic gelatin hydrogel to a smaller extent than the two other growth factors. Under in vitro non-degradation conditions, approximately 20% of the incorporated bFGF and TGF-beta1 was desorbed from the hydrogels within the initial 40 min, followed by no further substantial desorption, whereas large initial desorption was observed for BMP-2 and VEGF. When implanted in the back subcutis of mice, gelatin hydrogels were degraded over time. Each growth factor was retained in vivo being incorporated in the acidic gelatin hydrogel: the smaller the in vitro desorption amount from the hydrogel, the longer the in vivo retention time. The in vivo profile of bFGF and TGF-beta1 retention was in good accordance with that of the hydrogel. These findings indicate that the growth factor immobilized to the acidic gelatin hydrogel through ionic interaction was released in vivo as a result of hydrogel degradation.
authors.affiliation: Institute for Frontier Medical Sciences, Kyoto University, Japan.
authors.forename: M
authors.initials: M
authors.lastname: Yamamoto
authors.forename: Y
authors.initials: Y
authors.lastname: Ikada
authors.forename: Y
authors.initials: Y
authors.lastname: Tabata
mesh_terms: D000327:Adsorption; D000818:Animals; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins / Q000378:metabolism; D002417:Cattle; D016228:Endothelial Growth Factors / Q000378:metabolism; D016222:Fibroblast Growth Factor 2 / Q000378:metabolism; D005780:Gelatin / Q000737:chemistry*; D006133:Growth Substances / Q000378:metabolism*; D006801:Humans; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate / Q000737:chemistry*; D007477:Ions / Q000737:chemistry; D008222:Lymphokines / Q000378:metabolism; D011485:Protein Binding; D011994:Recombinant Proteins / Q000737:chemistry / Q000378:metabolism; D013552:Swine; D013696:Temperature; D013997:Time Factors; D016212:Transforming Growth Factor beta / Q000378:metabolism; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors
chemical_list: C525718:BMP2 protein, human; C525719:Bmp2 protein, mouse; D055396:Bone Morphogenetic Protein 2; D019485:Bone Morphogenetic Proteins; D016228:Endothelial Growth Factors; D006133:Growth Substances; D007477:Ions; D008222:Lymphokines; D011994:Recombinant Proteins; C508960:TGFB1 protein, human; D016212:Transforming Growth Factor beta; D053773:Transforming Growth Factor beta1; D042461:Vascular Endothelial Growth Factor A; D042442:Vascular Endothelial Growth Factors; C499469:recombinant human bone morphogenetic protein-2; D016222:Fibroblast Growth Factor 2; D020136:Hydrogel, Polyethylene Glycol Dimethacrylate; D005780:Gelatin