title: Amino-modified silica surfaces efficiently immobilize bone morphogenetic protein 2 (BMP2) for medical purposes.
abstract: Due to its ability to induce de novo bone formation the differentiation factor bone morphogenetic protein 2 (BMP2) is often used to enhance the integration of bone implants. With the aim of reducing possible high dose side-effects and to lower the costs, in order to produce affordable implants, we developed a simple and fast method for the immobilization of BMP2 on silica-based surfaces using silane linkers which carry amino or epoxy functions. We put an especial emphasis on the influence of the nanoscale surface topography of the silica layer. Therefore, we chose glass (for control experiments) and Bioverit® II (as a typical implant base material) as support materials and coated these substrates with unstructured or nanoporous amorphous silica layers for comparison. Immobilized BMP2 was quantified by two different methods: by ELISA and by a cell-based assay for active BMP2. These tests probe for immunologically and biologically active BMP2, respectively. The results show that the amino functionalization is better suited for immobilizing the protein. Strikingly, a considerably higher amount of BMP2 could be immobilized on coated Bioverit® II surfaces compared with coated glass substrates, which was presumably due to the macroscopic roughness of the Bioverit® II substrates. In addition, it was found that the nanoporous silica coatings on Bioverit® II substrates were able to bind more BMP2 than the unstructured ones.
authors.affiliation: Institut für Anorganische Chemie, Leibniz Universität Hannover, Hannover, Germany.
authors.forename: Nina
authors.initials: N
authors.lastname: Ehlert
authors.forename: Andrea
authors.initials: A
authors.lastname: Hoffmann
authors.forename: Tammo
authors.initials: T
authors.lastname: Luessenhop
authors.forename: Gerhard
authors.initials: G
authors.lastname: Gross
authors.forename: Peter P
authors.initials: PP
authors.lastname: Mueller
authors.forename: Martin
authors.initials: M
authors.lastname: Stieve
authors.forename: Thomas
authors.initials: T
authors.lastname: Lenarz
authors.forename: Peter
authors.initials: P
authors.lastname: Behrens
mesh_terms: D001672:Biocompatible Materials / Q000737:chemistry*; D055396:Bone Morphogenetic Protein 2 / Q000378:metabolism*; D002516:Ceramics / Q000737:chemistry; D020099:Coated Materials, Biocompatible; D005898:Glass / Q000737:chemistry; D006801:Humans; D055767:Immobilized Proteins / Q000378:metabolism*; D008422:Materials Testing; D058608:Nanopores / Q000648:ultrastructure; D012821:Silanes / Q000737:chemistry*; D012822:Silicon Dioxide / Q000737:chemistry*; D013499:Surface Properties; D014961:X-Ray Diffraction
chemical_list: D001672:Biocompatible Materials; C067324:Bioverit; D055396:Bone Morphogenetic Protein 2; D020099:Coated Materials, Biocompatible; D055767:Immobilized Proteins; D012821:Silanes; D012822:Silicon Dioxide