Friction Fighter

New hydrogel coatings may lead to better catheters and condoms.

Catheters, intravenous lines, and other types of surgical tubing are a medical necessity for managing a wide range of diseases. But a patient’s experience with such devices is rarely a comfortable one.

Now MIT engineers have designed a gel-like material that can be used to coat standard plastic or rubber devices, providing a softer, more slippery exterior that can significantly ease a patient’s discomfort. The coating can even be tailored to monitor and treat signs of infection.

The team has developed a method to strongly bond a layer of hydrogel—a squishy, slippery polymer material that consists mostly of water—to common elastomers such as latex, rubber, and silicone. The results are “hydrogel laminates” that are soft, stretchable, and slippery as well as impermeable to viruses and other small molecules.

Compounds that sense inflammatory molecules or other troublemakers can be embedded into the hydrogel coating. Drugs can also be incorporated into it and slowly released to treat, say, inflammation or pain.

The team, led by Xuanhe Zhao, an associate professor of mechanical engineering, bonded layers of hydrogel to various elastomer-based medical devices, including catheters and intravenous tubing. They found that the coatings were extremely durable, able to bend and twist without cracking. The coatings were also extremely slippery, exhibiting much less friction than standard uncoated catheters.

The group also used hydrogel to coat another widely used elastomer product: condoms. In addition to enhancing the comfort of existing latex condoms by reducing friction, a coating of hydrogel could help improve their safety by incorporating drugs to counter a latex allergy, the researchers say.

In previous research, the team has “demonstrated hydrogel really has the potential to replace common elastomers,” Zhao says. “Now we have a method to integrate gels with other materials. We think this has the potential to be applied to a diverse range of medical devices interfacing with the body.”