Zurich researchers develop world’s smallest stent 

The microstent was developed by the Multi-Scale Robotics Lab at ETH Zurich. Keystone / Christian Beutler

Scientists in Zurich have developed the world’s smallest stent – 40 times smaller than previously possible.  

According to the Federal Institute of Technology in Zurich (ETH Zurich), the new microstents, which are 0.05mm wide and 0.5mm long, could be used to help widen life-threatening constrictions of the urinary tract in foetuses in the womb.  

Stents have been used to treat blocked coronary vessels for some time now, but the urinary tract in foetuses is much narrower in comparison.   

Paediatric surgeons at the Aargau Cantonal Hospital contacted the Multi-Scale Robotics Lab at ETH Zurich to propose a new smaller stent.  

The new microstent is just 50 micrometers (0.05 mm) wide and half a millimeter long. Carmela de Marco / ETH Zurich

The researchers used heat from a laser beam to cut a three-dimensional template – a 3D negative – into a micromould layer that was dissolved with a solvent. The negative was then filled with a polymer and set using UV light. The 3D stent was revealed by dissolving the template in a solvent bath.  

“The shape-memory polymer is suitable for treating urethral strictures. When compressed, the stent can be pushed through the affected area. Then, once in place, it returns to its original shape and widens the constricted area of the urinary tract,” paediatric surgeon Gaston de Bernardis said.  

In the next step, the stents must be tested in animal models before being tested in humans.