Towards a Better Corrosion Resistance and Biocompatibility Improvement of Nitinol Medical Devices

Haemocompatibility of Nitinol implantable devices and their corrosion resistance as well as resistance to fracture are very important features of advanced medical implants. The authors present novel methods capable of improving Nitinol implantable devices to some marked degree beyond currently used electropolishing processes. Specifically, a magnetoelectropolishing process is advised. A polarization study shows that magnetoelectropolished Nitinol surfaces are more corrosion resistant than those obtained after standard electropolishing and possess a unique ability to repassivate the surface. Furthermore, current sterilization processes for Nitinol implantable devices can dramatically alter the physicochemical properties of the devices, affecting their biocompatibility. Experimental results demonstrate effective strategies to enhance the biocompatibility of NiTi alloy surfaces, leading to recommendations for final sodium hypochlorite treatments to replace existing sterilization methods, thus providing a rationale for improving the overall quality and performance of Nitinol-based medical implants.