Vascular stents typically come in a number of different lengths and diameters. The physician implanting the device chooses the best fit for individual patients, but often the available sizes are not ideal. To address this need, researchers at Northwestern University turned to 3D printing to create stents of any size that are customized to each patient’s unique anatomy.
Researchers tweaked a technique called projection micro-stereolithography (PµSL), which works by projecting light onto a liquid photo-curable material that quickly solidifies. The new technique is called micro-continuous liquid interface production (microCLIP), and it can be used to print objects with a resolution down to 7 microns, an important characteristic for small stents.
The Northwestern researchers used a citric-acid based polymer as the building material, which is flexible, biodegradable, and works as an antioxidant. The same polymer can also host drugs, such as rapamycin, which is released as the stent slowly biodegrades to prevent restenosis.
The printing process is fast— it takes only a few minutes to make a stent—and can run in parallel to simultaneously produce multiple stents. The resulting stents are strong, even comparable to metal ones, and they don’t require fat struts that are typical of existing biodegradable stents.
Here you can watch the 3D printing technique print a stent.