| AVS 59th Annual International Symposium and Exhibition | |
| Biomaterial Interfaces | Monday Sessions |
| Session BI-MoM |
| Session: | Surfaces to Control Cell Response |
| Presenter: | O.Z. Andersen, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark |
| Authors: | O.Z. Andersen, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark V. Offermanns, Medizinische Universität Innsbruck, Universitätsklinik für Mund-, Kiefer- und Gesichtschirurgie, Austria M. Sillassen, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark D.C.E. Kraft, Aarhus School of Dentistry, Denmark J. Bøttiger, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark F. Besenbacher, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark F. Kloss, Medizinische Universität Innsbruck, Universitätsklinik für Mund-, Kiefer- und Gesichtschirurgie, Austria M. Foss, Interdisciplinary Nanoscience Center (iNANO), Aarhus University, Denmark |
| Correspondent: | Click to Email |
Introduction: Strontium (Sr) has been shown to have a beneficial influence on the subsequent remodelling of the bone structure in relation with implant osseointegration. Both decrease of the osteoclast driven bone resorption and enhancement of the osteoblast driven process of bone formation has been shown. Furthermore, Sr has proven to have an anti-inflammatory effect.
Methods: The coatings used in this study were either prepared on Ti implants (rods with diameter = 1.1 mm and length = 6 mm) or on silicon wafers. The Sr containing surface modifications were prepared by co-sputtering in a setup with a pure Ti and a sintered composite target. The samples were characterized using SEM, AFM, XPS and RBS. ICP-AES was used to investigate the amount of Sr released from the samples as a function of time. Human dental pulp stem cell (hDPSC) cultures were used to assess the in vitro cellular response: Cell attachment and proliferation was studied along with the cells ability to mineralize. Quantification of osteogenic expression markers and specific cytokines was performed via RT-PCR. Human blood derived monocyte cultures were carried out to investigate the in vitro differentiation of these into osteoclast-like cells in response to Sr. In vivo experiments were carried by inserting implants into the femur of Wistar rats and evaluation was done by assessing bone-to-implant contact and new bone volume.
Results: The amount of Sr incorporated in the surfaces was found to be between 0 and 8.7 at. %. The Sr release profile showed that the most Sr was released from samples incorporating 5.5 at. % Sr. In relation with the in vitroexperiments, the hDPSC proliferation and mineralization was found to correlate with the surface Sr concentrations. Moreover, the Sr concentration also affected the differentiation of monocytes into osteoclast-like cells. In relation with the in vivo experiment it was found that the incorporation of Sr had a beneficial effect on implant osseointegration, where an increase in direct bone contact and in new bone volume was observed with an increasing Sr release.
Discussion: From the in vitro and in vivo Sr release experiments it was found that a more dense surface structure developed as the Sr concentration were increased. We therefore speculate that the peak in the Sr release around 5.5 at.% can be ascribed to an optimal correlation between the morphology and the amount of incorporated Sr. The results from the in vitro and in vivo models shows that the coating process we have developed for modifying implants is an interesting candidate in relation with shortening the healing period when inserting osseointegrating implants.