Aptamer-based capture molecules as a novel coating strategy to promote cell adhesion.

The improvement of the cytocompatibility of medical implants is a major goal in biomaterials research. During the last years many researchers worked on the fascinating approach to seed the respective cell types on various artificial substrates before implantation. For instance, cell-seeded implants are supposed to be better candidates for transplantable bone substitutes than conventional artificial bone grafts. To improve cell seeding efficiency and cytocompatibility, we designed a new coating material for medical implants. We used aptamers, highly specific cell binding nucleic acids generated by combinatorial chemistry with an in vitro selection called systematic evolution of exponential enrichment (SELEX). Aptamers do have high binding affinity and selectivity to their target. In our study, human osteoblasts from osteosarcoma tissue were used as a target to create the aptamer. Single aptamer mediated cell sorting assays showed the binding affinity with osteoblasts. Additionally, the aptamers immobilized on tissue culture plates could capture osteoblasts directly and rapidly from the cell solution. This model proves that aptamer coated artificial surfaces can greatly enhance cell adhesion. We assume that this strategy is capable to improve the clinical application of tissue engineered implants.