When a medical implant such as a stent or catheter is rejected by the body, blood platelets adhere to the device, forming a clot that encapsulates it. Those clots can in turn lead to heart attacks, embolisms or infections. One solution is to put patients on blood-thinning medications for the rest of their lives. Engineers at Colorado State University, however, have developed an alternative – blood-repellent titanium that could be used to build the implants.
More specifically, lead scientists Arun Kota and Ketul Popat have grown superomniphobic (liquid-repelling) surfaces on sheets of titanium. While different types of surfaces have been trialled in lab tests, the surface texture and chemistry of fluorinated nanotubes was found to produce the lowest level of platelet adhesion. They're pictured below.
What it all comes down to is creating a surface that's so superhemophobic – blood-repelling – that the blood doesn't even register the implant as a foreign body that needs to be isolated. "We are taking a material that blood hates to come in contact with, in order to make it compatible with blood," says Kota.
"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," adds Popat. "Here, we're targeting the prevention of the first set of events."
The scientists are now hoping to test the technology on actual implanted devices. A paper on their research was recently published in the journal Advanced Health Care Materials.