Prototyping of biodegradable flat stents in pure zinc by laser microcutting and chemical etching

Cardiovascular stents are biomedical devices, which restore normal blood flow in the case of coronary artery obstructions. Biodegradable metals provide the possibility of a less-invasive treatment, where the stent is dissolved in body fluids after remodelling of the artery. Compared to Mg-and Fe-alloys, Zn and its alloys provide optimal corrosion rates as a more recent option. New Zn-alloys are under development and often need to be tested for corrosion and biological properties. However, Zn and its alloys still require further investigation in terms of the production routes involved for stent manufacturing. Especially at a prototyping stage, the extrusion of thin biodegradable tubes is an expensive and difficult process. This work investigates a novel manufacturing route consisting of laser microcutting and chemical etching of pure Zn sheets to develop inflatable devices that can take a tubular form. Initially, laser microcutting parameters were studied to understand the dross formation on a low melting point material. Chemical etching of the material with low corrosion resistance was investigated for the dross removal. Prototype flat stents were produced and expanded using a medical catheter.