Regulated Drug Release With Nano Bubbles

Picture: Nano pores on surface

Modified highly nano porous
surface of a stent; © FZD

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. 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.

Physicists and chemists at the Forschungszentrum Dresden-Rossendorf (FZD) developed an innovative method to create a large number of tiny pores with a diameter of a few ten to a few hundred nano meters (one nano meter being one millionth of a millimeter) on the surface of stainless steel. Dr. Natalia Shevchenko and Dr. Andreas Kolitsch from the FZD Ion-Beam Center bombard the surface of a stent from all sides with a high dose of noble gas ions.

This generates a scaffold of nano pores in the material below the surface. Tuning the ion energy, the flux and the temperature during the process, the desired porosity can be precisely engineered. A larger amount of the highly effective drugs can be deposited on the enlarged noble metal surface, due to this nano porous structure, which enhances the biocompatibility of the implants in the human body. Thus, this treatment results in the release of drugs over a longer period of time.; Source: Forschungszentrum Dresden-Rossendorf