Coronary Stent

AFM image of the surface of a coronary stent strut for the treatment of heart disease in interventional cardiology. The stent made of stainless steel was electro-chemically etched. The strut has a curved shape, a width of 140 µm and a thickness of 120 µm. The metal dissolution by the acid takes place mainly at the grain boundaries of the metal structure which leads to cavities that can be used for drug delivery. The image with a scan size of 60 µm was taken with a MFP-3D in tapping mode in air. Image courtesy of M. Geisler, Institute of Medical Engineering, Technische Universität München.