1Department of Oral and Maxillofacial Surgery, University Hospital Tübingen 2Department of Thoracic, Cardiac and Vascular Surgery, University Hospital Tübingen

Herein we report on the identification of a DNA molecule (aptamer) towards osteogenic progenitor cells from different origins. The aim was to use the aptamer as a capturing molecule for the immobilization of biomaterials or for specific selection of subpopulations. The aptamer was generated using the technique called SELEX (systematic evolution of ligands by exponential enrichment). In this study, we were able to generate for the first time an aptamer binding to osteogenic induced jaw periosteal cells (JPCs). Similar binding affinities were detected towards mesenchymal stem cells (MSCs) derived from placental tissue and bone marrow. In contrast, no selective binding affinity of the aptamer to chondrogenically and/or adipogenically induced MSCs or other cell lines tested could be measured. Comparative analyses of aptamerpositive and-negative sorted JPCs resulted in no significant differences concerning osteogenic marker gene expression. However, we detected stronger mineralization and a higher content of calcium phosphate precipitates of the aptamer-positive cell fraction under 2D- and 3D-culture conditions. Summarizing our results, we were able to generate an aptamer that binds with a higher affinity towards osteogenically induced JPCs. Further studies should clarify the target molecule of the identified aptamer and modification attempts should be undertaken to stabilize the DNA molecule