Nanotechnology in Medicine: nanostructures and scaffolds to regenerate the vascular system

Regenerative medicine is an emerging multidisciplinary field that aims to restore maintain or enhance tissues and hence organ functions. Regeneration of tissues can be achieved by the combination of living cells, which will provide biological functionality, and malerials, which act as scaffolds to suppon cell proliferation. Mammalian cells behave in vivo in response to the biological signals they receive from the surrounding environment, which is structured by nanometer-scaled components. Therefore, materia is used in repairing the human body have to reproduce the correct signals that guide the cells towards a desirable behavior. Nano technology is not only an excellent tool to produce material structures that mimic the biological ones but atso holds the premise of providing efficient delivery systems. The application of nanotechnology to regenerative medicine is a wide issue and this short review will only focus on aspects of nanotechnology relevant to the vascular system. Specifically, the coating of synthetic graft surfaces with capture molecules for circulating endothelial progenitor cells (EPCs) that mimics a pro-homing substrate for fishing out EPCs directly from the bloodstream after implantation, will be addressed. These cells with high proliferation potential can cover the graft with non-throm bogenic endothelium which maintains optimal haemostasis and minimize the risk of restenosis. Different concepts are discussed to capture circulating EPCs on synthetic vascular grafts after implantation. We hypothesize that in vivo self-endothelialisation of blood contacting materials by homing factor-mimetic capture molecules for EPCs may bring revolutionary new perspectives towards future clinical application of stem cell and tissue engineering strategies.