Degradation Behavior of Nanostructured Stent Materials Using Cold Spray

Very late stent thrombosis (ST) stent fracture (SF) increases restenosis rate of permanent drug eluting stents (DES). In fact, permanent stents after arterial remodeling (change of artery dimensions during atherosclerosis) process becomes a supportive part inside our body and this idea lead us to develop biodegradable stents which support till arterial remodeling and progressively degrade thereafter. In this research, cold gas dynamic spray technique, simply referred to as cold spray is introduced to spray micro particles on metallic plane and cylindrical substrate. Reference material for permanent stent, stainless steel, 316L is mixed with pure iron in different proportions to induce microgalvanic corrosion effect on as sprayed specimens. Although annealed 316L coatings indicate better ultimate strength, porosity and ductility, their degradation study signifies their poor degradability in Hank’s physiological solution. In contrast to that, immersion and potentiodynamic polarization tests under Hank’s physiological solution indicate that corrosion rate of as sprayed composite increases as amount of iron increases. More iron particles release more iron ions and increases corrosion rate in hanks solution.