Stents are medical implants that, for example, prevent the blocking of arteries after surgery.
One of the problems using stents is the biocompatibility as the human body rejects and attacks foreign material. The Forschungszentrum Dresden-Rossendorf (FZD) developed a new method for making the surface of metal stents highly nano porous by producing millions of nano bubbles underneath. This enlarged surface allows depositing and slowly releasing drugs over a longer period of time than with usual drug eluting stents. The market leader for stents, the Boston Scientific Corporation in the US, focuses on this route to prevent the rejection of cardiovascular stents as this allows the targeted release of the drug right at the walls of the blood vessels.
Stents are implanted in certain organs as a supporting scaffold that reinforces the organ walls. Vascular stents act as small tubes made of metal or plastic mesh. The major problem in the application of stents is their compatibility with the human tissue: About 20 to 30 percent of the patients react with the rejection and the shut-down of the vessel. During the 1990's, vascular stents, which are coated with different substances, have been developed in order to solve this problem. This kind of drug eluting stent releases small amounts of a certain drug that constrains the regeneration of cells. In addition to the more conventional bare metal stent, more and more coated stents are used in Germany since 2002, especially for the treatment of coronary heart disease. Drug eluting stents are particularly effective in the treatment of diabetic patients, which make up 30% of the interventionally treated coronary patients and also carry the highest risk for renewed narrowing.