M.Sc. Candidate Daniel Safranchik, Haifa Campus,
Materials Science and Engineering, Technion, Haifa
During the last decade, an extensive research has been performed in an effort to develop biodegradable metallic stents as an alternative to permanent ones.
The role of the biodegradable stent is temporary until healing of the blood vessel occurs in 6-12 months. Moreover, in certain cases degradable implants may outperform permanent devices, by averting prolonged physical irritation and chronic inflammation.
The mechanical properties of the material should be similar to those of 316LVM stainless steel, which is the gold standard for stents, providing suitable mechanical properties to support diseased arteries. Controlling the corrosion rate is necessary in order to get the required lifetime of the stent, while non-toxicity is essential as the material is absorbed in the body.
Alloying elements such as Manganese can lead to faster degradation rates as this element lowers the Red-Ox potential of Iron. Manganese can also change the magnetic properties of Fe making it antiferromagnetic – a desired effect since strong magnetic properties can alter and disrupt MRI scan. These effects have been extensively researched, yet no significant research has been done on the effect of production methods on the desired properties mentioned.
In our study, we investigated how different casting methods, alloying elements and chemical compositions affect the device’s properties. After metallographic characterization, we performed in-vitro corrosion measurements and determined mechanical properties of our alloys. Electrochemical and weight loss methods were used to determine the degradation characteristics.