title: The effect of sulfation of alginate hydrogels on the specific binding and controlled release of heparin-binding proteins.
abstract: To mimic the high affinity of heparin-binding proteins to heparin/heparan sulfate, the uronic acids in non-sulfated alginate were sulfated, and hydrogels of mixed alginate/alginate-sulfate were fabricated. Surface plasmon resonance analysis probed the interactions of 13 proteins with alginate-sulfate. Of these, the 10 heparin-binding proteins revealed strong binding to alginate-sulfate and heparin, but not to alginate. The equilibrium binding constants to alginate-sulfate were comparable or one order of magnitude higher than those obtained between the proteins and heparin. Only the fibroblast growth factors (FGFs) revealed higher affinity for heparin than to alginate-sulfate. Sulfation of hyaluronan, as well, resulted in strong binding of basic FGF to hyaluronan-sulfate, but not to hyaluronan. Mixed hydrogels of alginate/alginate-sulfate sustained the release of basic FGF, with the release rate being dependent on the percentage of bFGF bound to the hydrogels. In vivo, the delivery of bFGF bound to alginate/alginate-sulfate scaffolds induced the formation of twice the number of blood vessels compared to when bFGF was delivered adsorbed to the matrix and 51% of the vessels were matured, as judged by pericyte coverage of the vessels. Our results thus describe the engineering of alginate hydrogels for the spatially presentation and controlled delivery of heparin-binding proteins.
authors.affiliation: Department of Biotechnology Engineering, Ben-Gurion University of the Negev, 84105 Beer Sheva, Israel.
authors.forename: Inbar
authors.initials: I
authors.lastname: Freeman
authors.forename: Alon
authors.initials: A
authors.lastname: Kedem
authors.forename: Smadar
authors.initials: S
authors.lastname: Cohen
mesh_terms: D000464:Alginates / Q000737:chemistry*; D000818:Animals; D023181:Antimicrobial Cationic Peptides / Q000737:chemistry / Q000378:metabolism*; D001798:Blood Proteins / Q000737:chemistry / Q000378:metabolism*; D002352:Carrier Proteins / Q000737:chemistry / Q000378:metabolism*; D016222:Fibroblast Growth Factor 2 / Q000737:chemistry / Q000378:metabolism; D020723:Glucuronic Acid / Q000737:chemistry; D006603:Hexuronic Acids / Q000737:chemistry; D020100:Hydrogels / Q000737:chemistry* / Q000494:pharmacology; D008297:Male; D008863:Microspheres; D015394:Molecular Structure; D011485:Protein Binding / Q000187:drug effects; D051381:Rats; D017207:Rats, Sprague-Dawley; D013431:Sulfates / Q000737:chemistry*; D020349:Surface Plasmon Resonance
chemical_list: C062991:AZU1 protein, human; D000464:Alginates; D023181:Antimicrobial Cationic Peptides; D001798:Blood Proteins; D002352:Carrier Proteins; D006603:Hexuronic Acids; D020100:Hydrogels; D013431:Sulfates; D016222:Fibroblast Growth Factor 2; D020723:Glucuronic Acid