title: Chemically-conjugated bone morphogenetic protein-2 on three-dimensional polycaprolactone scaffolds stimulates osteogenic activity in bone marrow stromal cells.
abstract: Poly(ε-caprolactone) (PCL) has received considerable attention in bone tissue engineering. However, the lack of osteoinductive ability of PCL limits its application. The aim of this study was to directly attach bone morphogenetic protein-2 (BMP-2) to PCL scaffolds by a crosslinking conjugation method and to investigate whether the bound BMP-2 maintained bioactivity in vitro. Immunofluorescent staining against BMP-2 and quantitative enzyme-linked immunosorbent assay measurements demonstrated that BMP-2 was successfully immobilized on the PCL three-dimensional scaffold by aminolysis and subsequent chemical conjugation. Conjugation produced much higher immobilization efficiency than the physical adsorption. Conjugated BMP-2 release from the PCL scaffolds was significantly slower than that from BMP-2-adsorbed PCL scaffolds over 15 days, which resulted in more BMP-2 locally retained on the conjugated scaffold. Further, the downstream Smads pathway was upregulated in bone marrow stromal cells cultured on the BMP-2-conjugated PCL scaffolds. Finally, gene expression of osteogenic markers (alkaline phosphatase, osteoclacin, and type I collagen) was upregulated in bone marrow stromal cells cultured on the PCL scaffolds with BMP-2 conjugation, but not on PCL scaffolds after BMP-2 adsorption. Therefore, our finding demonstrated that BMP-2 conjugation on polyester scaffolds is a feasible way to impart scaffolds with osteoinductive capability.
authors.affiliation: Department of Biomedical Engineering, University of Michigan, Ann Arbor, Michigan 48109, USA.
authors.forename: Huina
authors.initials: H
authors.lastname: Zhang
authors.forename: Francesco
authors.initials: F
authors.lastname: Migneco
authors.forename: Chia-Ying
authors.initials: CY
authors.lastname: Lin
authors.forename: Scott J
authors.initials: SJ
authors.lastname: Hollister
mesh_terms: D000327:Adsorption / Q000187:drug effects; D000818:Animals; D015415:Biomarkers / Q000378:metabolism; D001854:Bone Marrow Cells / Q000166:cytology* / Q000187:drug effects* / Q000378:metabolism; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D052006:Bone Morphogenetic Protein Receptors, Type II / Q000378:metabolism; D005455:Fluorescent Antibody Technique; D005786:Gene Expression Regulation / Q000187:drug effects; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism; D010012:Osteogenesis / Q000187:drug effects* / Q000235:genetics; D011091:Polyesters / Q000494:pharmacology*; D051381:Rats; D017207:Rats, Sprague-Dawley; D017154:Stromal Cells / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D054457:Tissue Scaffolds / Q000737:chemistry*
chemical_list: D015415:Biomarkers; D055396:Bone Morphogenetic Protein 2; D055767:Immobilized Proteins; D011091:Polyesters; C016240:polycaprolactone; D052006:Bone Morphogenetic Protein Receptors, Type II