Corrosion resistance of hydrofluoric acid-treated Mg alloy stent after expansion

Magnesium (Mg) alloy has been actively investigated as a bioresorbable scaffold (BRS) for use as a next-generation stent because of its appropriate mechanical properties and biocompatibility. However, Mg alloy quickly degrades in the physiological environment. Hydrofluoric acid (HF) treatment and surface coating with biodegradable polymer are approaches for enhancing the corrosion resistance of Mg alloy. However, there are no studies that focus on the corrosion behavior of the Mg alloy stent after balloon catheter expansion, which results in mechanical stress and is required for stent placement.

High corrosion resistance

Therefore, the corrosion behavior of a Mg alloy stent after expansion by a balloon catheter was investigated. Compared with the bare Mg alloy stent, the HF-treated Mg alloy stent showed excellent corrosion resistance without expansion. However, balloon catheter expansion caused small fragments and cracks to appear on the surface of the HF-treated Mg alloy stent and accelerated its corrosion rate. The HF-treated Mg alloy stent was therefore further coated with polyactic acid. As a result, the high corrosion resistance of the coated stent was maintained after its expansion along with higher biocompatibility for endothelial cell adhesion than the stent without the polymer coating.

The study has been published in Journal of Coatings Technology and Research volume 17 (2020).

Image source: Pixabay.