Surface modification of a novel porous titanium dioxide/glass composite

A novel technique is used to produce an open porous titanium dioxide/glass composite, named Ecopore, with promising structural and biological properties for the development as a bone graft. This study aims at a fast and lasting integration of the new material by means of biochemical surface modification. Surface etching of Ecopore, aminosilanization and covalent coupling of the cellular attachment mediator fibronectin was employed as modification strategy. In a comparison of different etching procedures, alkaline etching led to the highest density of amino functions after subsequent ammosilanization. Fibronectin was immobilized using a bifunctional aminoreactive PEG-linker. This protein coating improved the attachment of human osteoblast-like cells (HOB) on non-porous Ecopore as displayed by vital staining. XTT metabolism assays indicated an enhanced HOB growth in the initial phase of cultivation on fibronectin-coated versus non-coated specimens. In a first feasibility study, cultivation of HOB on coated porous Ecopore cylinders with a median pore size diameter of 130 mum showed that cellular growth was uniform and dense on the external surface of the specimen, but was sparse in the interior pore system. Ecopore batches with larger pores will be modified and investigated in vitro and in vivo in the next step of the study.