title: Apatite-coated collagen scaffold for bone morphogenetic protein-2 delivery.
abstract: Bone morphogenetic proteins (BMPs) are the most potent osteoinductive growth factors. BMP-2 is clinically used for spine fusion and bone fracture healing. Commercially available BMP-2 uses a type I collagen scaffold as a carrier, but it only releases BMP-2 for a short period of time, which may release the bone formation efficacy. In the present study, we hypothesize that apatite coating of a collagen scaffold increases the release period as well as the osteogenic efficacy of BMP-2. Apatite coating was achieved by incubating collagen scaffolds in simulated body fluids (SBFs). Apatite coating on collagen scaffolds was confirmed by X-ray diffraction, electron spectroscopy for chemical analysis, attenuated total reflectance-Fourier transform infrared spectroscopy, and scanning electron microscopy. The rate and period of BMP-2 release from apatite-coated collagen scaffolds varied depending on the concentration of SBFs used. The 5× and 10× SBF apatite-coated collagen scaffolds released 91.8%±11.5% and 82.2%±13.1% of their loaded BMP-2 over 13 days in vitro, respectively, whereas noncoated collagen scaffold released 98.3%±2.2% over the initial one day. BMP-2 released from apatite-coated collagen scaffold significantly increased the alkaline phosphatase activity of cultured osteoblasts, compared with BMP-2 released from noncoated collagen scaffold. Computed tomography and histomorphometry showed that BMP-2 delivery using apatite-coated collagen scaffolds resulted in 2.5-fold higher bone formation volume and 4.0-fold higher bone formation area than BMP-2 delivery using noncoated collagen scaffolds. This study shows that simple apatite coating of a collagen scaffold results in a BMP-2 carrier that renders long-term release of BMP-2 and dramatically enhances osteogenic efficacy.
authors.affiliation: Department of Bioengineering, Hanyang University, Seoul, Republic of Korea.
authors.forename: Hee Seok
authors.initials: HS
authors.lastname: Yang
authors.forename: Wan-Geun
authors.initials: WG
authors.lastname: La
authors.forename: Suk Ho
authors.initials: SH
authors.lastname: Bhang
authors.forename: Tae-Jin
authors.initials: TJ
authors.lastname: Lee
authors.forename: Minhyung
authors.initials: M
authors.lastname: Lee
authors.forename: Byung-Soo
authors.initials: BS
authors.lastname: Kim
mesh_terms: D000818:Animals; D001031:Apatites / Q000737:chemistry*; D055396:Bone Morphogenetic Protein 2 / Q000737:chemistry*; D003094:Collagen / Q000737:chemistry* / Q000648:ultrastructure; D051379:Mice; D008855:Microscopy, Electron, Scanning; D023822:Tissue Engineering; D054457:Tissue Scaffolds / Q000737:chemistry; D014961:X-Ray Diffraction
chemical_list: D001031:Apatites; D055396:Bone Morphogenetic Protein 2; D003094:Collagen