By Benjamin Ross

March 26, 2019 | When he first heard about the project looking to use Shrinky Dinks for asthma research, Michael Chu didn’t know what to think.

“I will admit I was a little skeptical,” Chu, a PhD candidate and researcher at the Khine Laboratory at the University of California, Irvine, told Clinical Research News. “I always had this mindset that research needed to be done with very serious research tools, that that was how science was done.”

But Chu’s PI, Michelle Khine, envisioned using the children’s toy to analyze  respiration monitoring and developed a wearable sensor that measures both respiration rate and volume with high fidelity simultaneously. The results from the project were recently published in Nature (DOI:https://doi.org/10.1038/s41746-019-0083-3).

Khine is a professor in the Department of Biomedical Engineering at UC, Irvine, and she says the standard practice of monitoring respiration is not always effective.

“The gold standard is to look at both volume and rate, and that’s done with spirometry, which uses a big mask that you have to actively blow into,” Khine told Clinical Research News. For people with chronic asthma problems, and even for healthy patients, it’s difficult to breath heavily for the duration of the test.

“There are signs of exacerbation that are very subtle and may not be noticed by the patient when they’re coming on,” Khine says. “But because of the sensitivity of our sensors, we can look at these changes in respiration volume and detect patterns to indicate when adverse events might occur.”

Researchers created wearable sensors that stuck to patients like tape or a Band-Aid to patients’ abdomens and ribcages, measuring the local strain of both regions when the patients take a breath. Shrinky Dinks were used as the fabrication platform for the wearable devices. Once the material was shrunk to get the desired micro and nanostructures, researchers would lift off the Shrinky Dinks and place the electronics on a compliant, Band-Aid like material.

Chu’s role was to apply the sensors to a small pilot study, and then correlate the respiration volume and rate to a standard spirometry. He says the convenience of the wearable sensor made the collection of data a much easier task, and turnaround time from collection to analysis was reduced as well.

“The nice thing about this platform is that we’re able to go through many iterations of the same sensors rapidly,” Chu says. “Traditionally when you want to fabricate these types of sensors you have to do it through the cleanroom. But because of this platform you can really get an idea of what we have in the morning and be done by the afternoon, and that helps iterate through multiple sensors quickly.”

The quarter-sized form of the sensors also made it possible to collect data in the patients’ daily environments, something previous sensors were too cumbersome to do.

The goal, Khine says, is to be able to monitor exacerbation of chronic respiratory disease (CRD), such as asthma and chronic obstructive pulmonary disease (COPD), and eventually catch and prevent them before they occur.

Child’s Play

A need for resourcefulness played a big role in developing these sensors, Khine says. When she began her career as an assistant and founding professor of engineering at UC Merced, the school lacked the infrastructure Khine needed to continue her research. So Khine used her favorite children’s toy, Shrinky Dinks, to create the tools she needed.

“Shrinky Dinks is a pre-stressed shape memory polymer—so it retracts to its original size when it's heated,” Khine explained in an email interview. “I wanted something that you can pattern at the large scale (which is inexpensive and easy) and then shrinks to create the micro or nanofeatures that I need afterwards.”

“It’s amazing how many sensors you can build from a single platform, with the added advantage of everything being low cost and very fast,” Chu added. “With wearable technology, I expect everything to grow in the next decade. I’m excited to see where everything goes.”

While the focus of their recent work has been on respiration, Khine  hopes the sensors will be able to monitor all types of vitals, including continuous blood pressure monitoring. There has also been talk about making these sensors commercially available.

“It’s really come full circle because we’re moving toward developing this to be an active monitor for children,” she said. “I guess the ironic part of this is, is that this device came from a kids’ toy.”