title: Enhancing bioactivity of chitosan film for osteogenesis and wound healing by covalent immobilization of BMP-2 or FGF-2.
abstract: This study compares the efficacy of growth factors that are covalently immobilized to those that are adsorbed in improving the bioactivity of a biomaterial. Bone morphogenetic protein-2 (BMP-2) or fibroblast growth factor-2 (FGF-2) was covalently bonded to chitosan films using carbodiimide chemistry. For BMP-2, a growth factor loading efficiency of ∼64% was obtained with this method compared to ∼25% from adsorption. As for FGF-2, the growth factor loading efficiency of the two methods was similar at ∼50%. The covalently immobilized BMP-2 promoted attachment, proliferation, and differentiation of osteoblasts in a dose-dependent manner, whereas the covalently immobilized FGF-2 stimulated fibroblast attachment, proliferation, and collagen synthesis. After three weeks immersion in phosphate buffered saline, about 80% of the covalently immobilized growth factors were retained on the films, while only ∼16 and ∼21% of the adsorbed BMP-2 and FGF-2 remained on the corresponding films. The higher retention rate of the covalently immobilized growth factors enabled their stimulatory effects to persist for a longer period than when adsorbed growth factors were used.
authors.affiliation: Department of Chemical and Biomolecular Engineering, National University of Singapore, Singapore 117576, Singapore.
authors.forename: Rusdianto
authors.initials: R
authors.lastname: Budiraharjo
authors.forename: Koon Gee
authors.initials: KG
authors.lastname: Neoh
authors.forename: En-Tang
authors.initials: ET
authors.lastname: Kang
mesh_terms: D016475:3T3 Cells; D000327:Adsorption; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D002448:Cell Adhesion / Q000187:drug effects; D002454:Cell Differentiation / Q000187:drug effects; D049109:Cell Proliferation / Q000187:drug effects; D048271:Chitosan / Q000737:chemistry*; D016222:Fibroblast Growth Factor 2 / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D005347:Fibroblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D006801:Humans; D055767:Immobilized Proteins / Q000008:administration & dosage / Q000737:chemistry / Q000494:pharmacology*; D051379:Mice; D010006:Osteoblasts / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects*; D013718:Tensile Strength; D014945:Wound Healing / Q000187:drug effects
chemical_list: D001672:Biocompatible Materials; D055396:Bone Morphogenetic Protein 2; D055767:Immobilized Proteins; D016222:Fibroblast Growth Factor 2; D048271:Chitosan