title: BMP-2 tethered hydroxyapatite for bone tissue regeneration: coating chemistry and osteoblast attachment.
abstract: The goal of this study was to determine the effectiveness of using polyethyleneimine (PEI) and a polyethylene glycol (PEG) tether to bind human recombinant bone morphogenetic protein-2 (rhBMP-2) to hydroxyapatite (HAp) to enhance rhBMP-2 loading, alter its release properties, and enhance cellular interaction with the material. By using a branched PEI that was derived to express free thiols, rhBMP-2 was coated onto dense HAp surfaces at ~43 ng/cm(2). Using this novel attachment methodology, it was observed that the PEI-SH coating did not change the morphology of the HAp surfaces and that the amount of rhBMP-2 loaded was comparable to a direct adsorption method. In addition, it was also observed that the PEI and PEG tether significantly retained the rhBMP-2 to the HAp surface, inhibiting the burst release effect. Using human fetal osteoblast cells, the PEI- and PEG-tethered BMP-2 was also observed to increase cellular attachment by 10-fold when compared with uncoated HAp and adsorbed rhBMP-2. It was concluded from this study that PEI and PEG tether significantly reduce the initial burst release effect of rhBMP-2. It was also concluded that the rhBMP-2 conjugation to PEI and PEG tether promoted an increase in cellular attachment to the HAp surface.
authors: Department of Biomedical Engineering, The University of Texas at San Antonio, San Antonio, Texas, USA. scrumlett@gmail.com
authors: Stefanie M
authors: SM
authors: Shiels
authors: Kimberly D
authors: KD
authors: Solomon
authors: Marcello
authors: M
authors: Pilia
authors: Mark R
authors: MR
authors: Appleford
authors: Joo L
authors: JL
authors: Ong
mesh_terms: D055396:Bone Morphogenetic Protein 2 / Q000008:administration & dosage*; D001861:Bone Regeneration; D002448:Cell Adhesion; D002460:Cell Line; D020099:Coated Materials, Biocompatible / Q000737:chemistry*; D003692:Delayed-Action Preparations / Q000737:chemistry*; D017886:Durapatite / Q000737:chemistry*; D006801:Humans; D010006:Osteoblasts / Q000166:cytology*; D011092:Polyethylene Glycols / Q000737:chemistry; D011094:Polyethyleneimine / Q000737:chemistry; D011994:Recombinant Proteins / Q000008:administration & dosage; D016212:Transforming Growth Factor beta / Q000008:administration & dosage*
chemical_list: D055396:Bone Morphogenetic Protein 2; D020099:Coated Materials, Biocompatible; D003692:Delayed-Action Preparations; D011994:Recombinant Proteins; D016212:Transforming Growth Factor beta; C499469:recombinant human bone morphogenetic protein-2; D011092:Polyethylene Glycols; D011094:Polyethyleneimine; D017886:Durapatite