Effect of Vaporized Hydrogen Peroxide and Nitrogen Dioxide Sterilization on Nitinol

Nitinol is used as the structural framework in numerous types of medical devices (e.g., guidewires, transcatheters, stents). The desire to understand the material compatibility of nitinol with vaporized hydrogen peroxide (VH₂O₂) and nitrogen dioxide (NO₂) sterilization is increasing in healthcare technology. As a result of increased regulatory pressure and capacity limitations related to ethylene oxide (EO) sterilization, the industry is seeking alternative, sustainable sterilization options. This study sought to characterize the corrosion resistance of nitinol metal alloy wire when exposed to varying levels of VH₂O₂ and NO₂ sterilization. Scanning electron microscopy (SEM) imaging and energy-dispersive X-ray spectroscopy (EDS) scans were performed to understand the effects of VH₂O₂ and NO₂ sterilization treatments on the surface morphology and chemical composition of nitinol. From the SEM-EDS results, no notable difference was observed when comparing VH₂O₂ and NO₂ test samples with nonsterile control samples. In addition, cyclic potentiodynamic polarization measurements were performed per ASTM F2129-19a to determine corrosion susceptibility. No considerable changes were detected in the electrochemical potential after VH₂O₂ and NO₂ sterilization treatments, when compared with the nonsterile control samples. SEM-EDS and corrosion test results indicated no considerable changes in the surface properties or electrochemical potential of the sterilized samples compared with the nonsterilized control samples. Therefore, nitinol metal showed promising results for compatibility with VH₂O₂ and NO₂ sterilization.