"Hydrophobic means when you put a drop of water on a surface, it beads up like water on a freshly waxed car," Carman said. "This is typically undesirable in reducing thrombosis. We wanted it to be hydrophilic, the opposite of hydrophobic."
The team began an elaborate study, exploring various treatments that would modify the surface structure of the thin-film Nitinol. During one test, Chun discovered a treatment that produced not just a hydrophilic response but a super-hydrophilic response, meaning the wetting angle goes to zero and there are no water beads on the surface.
The team conducted in vitro studies to see if platelets would adhere to the surface of their new chemically treated material. The tests were a success: Virtually no platelets adhered.
But they also realized that in vitro testing alone wouldn't convince the medical community that their material was definitely non-thrombogenic.
"With the Challenge Grant, we are beginning to do tests in animals again and have already seen that our film does remain patent," Carman said. "It's our understanding that very few, if any, covered stents out there that are put into 3- or 4- millimeter vessels will remain patent. We need to show with statistical relevance that our material stays patent longer than other systems commercially on the market. If we can do that, we would have something that could impact the world quite dramatically.
"While we are very optimistic it will work, we also understand that biology does not always behave how you would like it to. All of our r
|Contact: Wileen Wong Kromhout|
University of California - Los Angeles