Innovative Stent Design Aims to Combat Infections with Cilia Technology

Francesco Clavica and his research group developed an innovative prototype for bioabsorbent medical stents. From other research, this new design could bring a significant reduction in infections associated with implanted devices. The new stents are made of a silicon-based polymer. They’re equipped with hairlike appendages known as cilia, which greatly increase their capability to remain clean and operational.

These pioneering stents are lined with cilia that reach 100 micrometers high. That’s roughly the thickness of a piece of paper! When exposed to ultrasound, the cilia are capable of moving fluid at an average rate of 10 millimeters per second. This unique movement actively prevents the crystallized compounds from accumulating. It prevents the formation of sticky biofilms created by microbes, which typically result in infections from urinary stents and catheters.

These prototype stents have a rectangular cross-section. Each measures approximately 150 micrometers tall, 4 millimeters wide and 25 millimeters long. The stents have a set of shorter inner walls that are angled and lined with cilia. This kind of cleaning process is directly encouraged by these designs. According to Clavica, “If you create a carpet of cilia, they add to each other, so that’s why you get this jet.”

So, every year, more than 1.5 million stents are placed worldwide. Ureteral stents that connect the kidney to the bladder often require frequent exchange every three to six months. Microbial blockage due to their colonization on material surface, and mineral deposition further aggravates the complication, thus inducing frequent replacements.

For now, Clavica and his team are preparing to test the stents in pigs. This key step will allow them to assess the technology’s effectiveness in a complex living organism. Though exciting, this advanced design has at least eight years before it would be ready for patients. The researchers even imagine that in the future patients will be able to sanitize their medical devices from home.

Daniel Ahmed from ETH Zurich emphasized the natural inspiration informing this new design. He noticed that infant sea stars employed cilia to whip up whirlpools in the water. This speedy soiling technique of siphoning in foodstuff has influenced the design of those stents.