Harvard scientists develop super-repellent device coating

Glass slides were dipped in blood to demonstrate the effectiveness of TLP coating. Blood sticks to the slide on the left, while the TLP-coated slide on the right emerges clear.--Courtesy of Harvard's Wyss Institute

As med tech companies search for innovative ways to improve device implantation and patient outcomes, a new coating technology from Harvard University scientists could reduce blood clotting and bacterial infection associated with commonly used medical devices.

A team of researchers at Harvard's Wyss Institute is developing a Tethered-Liquid Perfluorocarbon surface (TLP) coating for devices from FDA-approved materials that repels blood from plastic, glass and metal, effectively reducing sepsis infections and preventing blood clots for at least 8 hours without the use of blood thinners such as heparin. The scientists published their findings in the October issue of Nature Biotechnology, and received funding from the Defense Advanced Research Projects Agency (DARPA) and the Wyss Institute for Biologically Inspired Engineering at Harvard University.

To test the technology, scientists implanted medical-grade tubing and catheters coated with the material in large blood vessels in pigs, and found that the coating prevented blood from clotting while also suppressing harmful biofilm formation. The team derived the material from SLIPS, a surface technology developed by Joanna Aizenberg, professor in the department of chemistry and chemical biology. SLIPS repels almost any liquid it comes in contact with, and acts as a barrier to materials such as ice, crude oil and blood.

"We were wonderfully surprised by how well the TLP coating worked, particularly in vivo without heparin," said Anna Waterhouse, one of the study's co-lead authors. "Usually the blood will start to clot within an hour in the extracorporeal circuit, so our experiments really demonstrate the clinical relevance of this new coating."

Scientists also found that tubing lines coated with TLP significantly reduced sepsis from Central-Line Mediated Bloodstream Infections (CLABSI) and that TLP-treated tubing that was stored for more than a year under normal temperature and humidity conditions still prevented clot formation. While most of the team's studies were performed on catheters and perfusion tubing, Harvard researchers hope to test the coating on more complex devices such as dialysis machines and ECMO, a machine used in the intensive care unit to help critically ill patients breathe.

"We feel this is just the beginning of how we might test this for use in the clinic," said co-lead author Daniel Leslie.

- read the release
- here's the Nature Biotechnology abstract

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