title: Anodic oxidized nanotubular titanium implants enhance bone morphogenetic protein-2 delivery.
abstract: Implant failure has been attributed to loosening of an implant from the host bone possibly due to poor osseointegration. One promising strategy for improving osseointegration is to develop a functional implant surface that promotes osteoblast differentiation. In this study, a titanium (Ti) surface was functionalized by an anodic oxidation process and was loaded with recombinant human bone morphogenetic protein-2 (rhBMP-2). The following four groups of Ti surfaces were prepared: machined (M), anodized machined (MA), resorbable blast medium (RBM), and anodized RBM (RBMA). The surfaces were characterized by scanning electron microscopy and contact angle measurements. The results showed that a Ti oxide layer (TiO(2)) was observed in the anodized surfaces in the form of nanotubes, approximately 100 nm in diameter and 500 nm in length. The hydrophilic properties of the anodized surfaces were significantly improved. The adsorbed rhBMP-2 loaded on the nonanodized surfaces and lyophilized showed spherical particle morphology. However, the adsorbed rhBMP-2 showed a dispersed pattern over the anodized surfaces. The velocity of the rhBMP-2 released from the surfaces was measured to determine if the anodized surface can improve in delivery efficiency. The results showed that the release velocity of the rhBMP-2 from the anodized surfaces was sustained when compared with that of the nonanodized surfaces. In addition, the rhBMP-2 released from the surface was found to be bioactive according to the alkaline phosphatase activity and the level of calcium mineral deposition. These results suggest that the TiO(2) nanotubular structure formed by anodizing is a promising configuration for sustained rhBMP-2 delivery.
authors.affiliation: Dental Science Research Institute and BK21 Project, School of Dentistry, Chonnam National University, Gwangju, Korea.
authors.forename: In-Ho
authors.initials: IH
authors.lastname: Bae
authors.forename: Kwi-Dug
authors.initials: KD
authors.lastname: Yun
authors.forename: Hyun-Seung
authors.initials: HS
authors.lastname: Kim
authors.forename: Byung-Chul
authors.initials: BC
authors.lastname: Jeong
authors.forename: Hyun-Pil
authors.initials: HP
authors.lastname: Lim
authors.forename: Sang-Won
authors.initials: SW
authors.lastname: Park
authors.forename: Kwang-Min
authors.initials: KM
authors.lastname: Lee
authors.forename: Young-Chai
authors.initials: YC
authors.lastname: Lim
authors.forename: Kyung-Ku
authors.initials: KK
authors.lastname: Lee
authors.forename: Yunzhi
authors.initials: Y
authors.lastname: Yang
authors.forename: Jeong-Tae
authors.initials: JT
authors.lastname: Koh
mesh_terms: D000327:Adsorption; D000818:Animals; D055396:Bone Morphogenetic Protein 2 / Q000737:chemistry / Q000494:pharmacology*; D002113:Calcification, Physiologic / Q000187:drug effects; D002460:Cell Line; D016503:Drug Delivery Systems / Q000379:methods; D006801:Humans; D020007:Implants, Experimental; D051379:Mice; D043942:Nanotubes; D010084:Oxidation-Reduction; D011994:Recombinant Proteins / Q000737:chemistry / Q000494:pharmacology*; D013499:Surface Properties; D014025:Titanium
chemical_list: C525718:BMP2 protein, human; D055396:Bone Morphogenetic Protein 2; D011994:Recombinant Proteins; C009495:titanium dioxide; D014025:Titanium