Healthcare materials wise up

By Mike Miliard
01:45 PM

Research at University of Pittsburgh and Harvard points to a future of "smart" materials at the point of care

PITTSBURGH  -  Seems like everything is "smart" nowadays. Smartphones. Smart TVs. Smart cars. For something to simply exist and perform its intended purpose is no longer enough; now everything must be technologically-advanced enough to all but think for itself.

Smart materials  -  which are capable of reacting and changing in response to stimuli such as temperature, or changes in pH or moisture levels  -  are getting more advanced by the day and could be poised for a bigger role in healthcare as the 21st century rolls along. 

There are pH-sensitive polymers, which change in size and volume when the pH of the surrounding medium changes. Photomechanical matter can shape-shift when exposed to light. There are even "self-healing" materials that can actually repair damage due to normal wear and usage.

Some new engineering experiments this summer at the University of Pittsburgh show promise for a type homeostatic material that can mimic the temperature responsiveness of the human body. Soon, researchers say, the smart material could be put to work toward smarter, more energy-efficient buildings  -  hospitals, say  -  and also in portable medical devices.

First published in the July 12 issue of Nature, the research, from a team of engineers from both Pitt and from Harvard, shows advancement in the field of self-regulating microscopic materials. 

Olga Kuksenok, a research professor in Pitt's Swanson School of Engineering, spearheaded the effort. She cautions that "it's not a technology yet," but more of "an idea."

But while "it's experimental," she said, the joint Pitt/Harvard research "did show that the system worked."

It works, essentially, by placing tiny, hair-like "posts" in a hydrogel solution. According to Pitt researchers, when the tips of these posts stand upright and interact with reagents in the upper fluid layer, they generate heat  -  which then causes the temperature-sensitive gel to shrink in size. When that happens, the posts then bend away from those reagents, and the system's temperature cools off. Consequently, the gel expands  -  resulting in the posts returning to an upright configuration.

"The reconfiguration of the gel creates an on/off switch of sorts for the system," which then "oscillates back and forth between these two states and, in this manner, regulates the overall temperature," said Kuksenok in a statement.

Called SMARTS (it stands for self-regulated mechano-chemical adaptively reconfigurable tunable system), the mechanism, which could interact with different stimuli  -  be it changes in temperature, pH or pressure  -  points the way toward the potential of setting off chemical reactions on cue, essentially reproducing the sort of stable "feedback loops" found in biological systems, say researchers.

The development of artificial materials that are "aware" of their internal goings-on holds potential for healthcare delivery, says Anna Balazs, distinguished professor of chemical and petroleum engineering at Pitt, who worked with Kuksenok on the study. For one thing, it could lead to smarter and more sophisticated biomedical analysis from portable diagnostic devices, she says. 

"This was a beautiful proof of principle  -  that you can make a synthetic system that is sensing and self-regulating, and actually mimics the body's ability to maintain temperature," says Balazs.

Still, "I think it will be a while yet before it is used in practical applications," she adds.

When that day comes, the area that shows most potential would be portable medical tools known as microfluidic devices  -  essentially "small-scale, portable chemical analysis labs," says Balazs, "hand-held devices used for bioassay at the point of care."

More and more, these devices are starting to be used for diagnosis not just of diseases, but also sampling and real-time testing of air/water samples for toxins and pathogens.

What smart materials such as the ones Balazs and Kuksenok pioneered could do is "help maintain the conditions of the device so the device could work precisely," says Balazs. It could "help maintain the temperature or pH of the device in a very nice autonomous way, so you don't need more circuitry, or you don't need to plug the device in to keep it in ideal working conditions."

That could be a "significant advance," she adds, "that you can keep small, hand-held devices in optimal operating conditions and therefore be able to perform more precise biological assays."

In the meantime, the Pitt/Harvard research is simply "a lovely demonstration that the phenomena that are happening in your body can be mimicked in a purely synthetic system."