Three-Layer Coating for Stents with Nanostructured Surface
A three-layer coating for stents with a nanostructured surface of calcium phosphate (CaP) is pre-sented. The coating stack consists of (a) a TiNbN layer deposited by physical vapour deposition and acting as diffusion barrier against allergenic ions, (b) a SiO2 xerogel layer providing good adhesion properties and designing the nanoporosity of the outer CaP layer (c) precipitated electrochemically. The verification of the SiO2-layer (and therewith its influence onto adhesion and structure of the outer CaP layer) succeeded only by use of XPS because of the very small amount of the xerogel. SEM results verified a homogeneous nanoscale nanoporous structure of the CaP coating. It is char-acterised by high adhesion strength. If applied for stent covering the nanoscale CaP coating has promising properties to initiate rapid endothelium formation and reduced risk of restenosis.
Marcelo Prado and Cecília Zavaglia
U. Beck et al., "Three-Layer Coating for Stents with Nanostructured Surface", Key Engineering Materials, Vols. 396-398, pp. 627-630, 2009