Medical implants like stents, catheters and tubing introduce risk for blood clotting and infection which are problematic for patients. The “superhemophobic” material specially grown by the engineers could form the basis for surgical implants with lower risk of rejection by the body.
It’s an outside-the-box innovation achieved at the intersection of two disciplines: biomedical engineering and materials science. The work is a collaboration between the labs of Arun Kota, assistant professor of mechanical engineering and biomedical engineering; and KetulPopat, associate professor in the same departments.
Kota, an expert in novel, “superomniphobic” materials that repel virtually any liquid, joined forces with Popat, an innovator in tissue engineering and bio-compatible materials.
Starting with sheets of titanium, commonly used for medical devices, their labs grew chemically altered surfaces that act as perfect barriers between the titanium and blood. Their teams conducted experiments showing very low levels of platelet adhesion, a biological process that leads to blood clotting and eventual rejection of a foreign material.
A material “phobic” (repellent) to blood might seem counterintuitive, the researchers say, as often biomedical scientists use materials “philic” (with affinity) to blood to make them biologically compatible. Kota said they are doing the exact opposite, taking a material that blood hates to come in contact with in order to make it compatible with blood.
The key innovation is that the surface is so repellent, that blood is tricked into believing there’s virtually no foreign material there at all.
The undesirable interaction of blood with foreign materials is an ongoing problem in medical research, Popat said. Over time, stents can form clots, obstructions, and lead to heart attacks or embolisms. Often patients need blood-thinning medications for the rest of their lives – and the drugs aren’t foolproof.
Popat said that the blood clots because it finds cells in the blood to go and attach with. “Normally, blood flows in vessels. If we can design materials where blood barely contacts the surface, there is virtually no chance of clotting, which is a coordinated set of events. Here, we’re targeting the prevention of the first set of events,”Popat added.
The researchers analyzed variations of titanium surfaces, including different textures and chemistries, and they compared the extent of platelet adhesion and activation. Fluorinated nanotubes offered the best protection against clotting, and they plan to conduct follow-up experiments.
Growing a surface and testing it in the lab is only the beginning, the researchers say. They want to continue examining other clotting factors, and eventually, to test real medical devices.