The stimulation of stem and progenitor cell recruitment by means of activation of the chemokine receptor CXCR4 will be investigated. New, highly active CXCR4 peptoid ligands recently developed in our laboratories will be studied. These compounds, which show an affinity for CXCR4 similar or higher compared to the natural ligand, CXCL12, are expected to strongly enhance the mobilization of adult stem cells. To achieve a controlled and continuous release, new degradable hydrogels capable of immobilizing or integrating the ligands will be developed.
We will further investigate the recruitment, attachment and fate of CXCR4-positive stem cells on polymeric matrices and artificial surfaces (e.g. titanium) of implants decorated with newly developed CXCR4 ligands immobilized on the aforementioned materials by means of suitable spacer and anchoring units. As differentiation and proliferation of stem cells is expected to occur at the site of injury (implantation), enhanced and faster healing of the damaged tissue is expected. Whereas attracted mesenchymal stem cells will differentiate into osteoblasts and hence promote bone remodeling, distinct stem cell types (e.g. hematopoietic stem cells) and progenitor cells (e.g. endothelial progenitor cells) may promote neovascularization and angiogenesis and fasten wound healing and tissue regeneration.