A Process towards Eliminating Cytotoxicity by Removal of Surface Contamination from Electrical Discharge Machined Nitinol
Robert Roth, Suat Coemert, Sarah Burkhardt, Katia Rodewald, Tim C. Lueth
Abstract
Electrical discharge machining (EDM) of biocompatible nitinol combines superelasiticity, high accuracy of fabrication and miniaturization capabilities, thus presenting a promising base material for flexible medical instruments in minimally invasive surgery. In order to remove cytotoxic surface contamination which is caused by brass wire in the standard EDM process, the effectiveness of a hydrofluoric acid and nitric acid based chemical etching process was tested. Here, Energy-dispersive X-ray spectroscopy proved the purity of the surface after etching, while cytotoxicity experiments showed great improvement in the reaction of human fibroblasts, shifting cell vitality to non-cytotoxic levels.