If you never created and played with Shrinky Dinks as a kid, they’re basically thin sheets of malleable plastic that are drawn on and then shrunk when put in the oven. The result is a very tiny and hard piece of plastic that has your masterpiece on it. Seemingly insignificant as a children’s toy, Shrinky Dinks are now being incorporated into a wearable that could help individuals with asthma, cystic fibrosis, and chronic pulmonary conditions.
Created by researchers at the University of California, Irvine, the wearable is a disposable respiration monitor that provides high-fidelity readings on a continuous basis. When UCI biomedical engineers went to work on creating a sensor for the device, they decided to use Shrinky Drinks.
The sensors are placed in two spots, one between the ninth and 10th ribs and another on the abdomen. The Band-Aid-like device then tracks the rate and volume of the wearer’s respiration by measuring the local strain on the sensor areas. In this case, the information acquired could help warn of an oncoming asthma attack.
“The current standard of care in respiration monitoring is a pulmonary function test that’s often difficult to perform and limited in terms of the snapshot it provides of a patient’s respiratory health—meaning problems can sometimes be missed,” said Michael Chu, UCI graduate student researcher in biomedical engineering and lead author of a paper on the innovation published today in npj Digital Medicine. “Our new stretch sensors allow users to walk around and go about their lives while vital information on the health of their lungs is being collected.”
The devices are created by applying a thin layer of metal to a Shrinky Dink-like sheet, and then heat shrinking it to cause corrugation. The film is then transferred to a soft, stretchy material, like a Band-Aid, that is adhered to the patient. Signals from the embedded sensors are transmitted via Bluetooth and displayed on a smartphone app.
The inspiration behind this device was initiated by Michelle Khine, UCI professor of biomedical engineering, whose lab developed the device. When Khine’s son was born nine months ago, he had complications that required the newborn to be confined to a neonatal intensive care unit that was hooked up to machines supplying oxygen that monitored his breathing.
“Despite having his whole tiny body covered in sensors, all the hospital staff could get was respiration rate information. If you looked at the vitals monitor, you’d see this waveform, so it looked like they were getting [respiration volume] information, but they weren’t,” said Khine. “I felt so helpless with my child just lying in this box. I wasn’t allowed to carry him for eight days, so it was heartbreaking—but also frustrating to see all of these wires hooked up to him but not giving all the information we wanted.”
This powerful moment was extremely motivating for her as a biomedical engineer.
“I sent some pictures of him all wired up to my students, and I said, ‘We have to be able to do better than this. This is 2018. It’s insane,'” she said.
Khine’s lab has previously used Shrinky Dinks as a platform for medical applications. About a decade ago, she used the toy to produce microfluidic devices.
“It’s amazing that this toy for kids has enabled us to create these robust sensors that may one day benefit children and others around the world,” she said.
In the upcoming months, Khine and her team have plans for a pilot trial with a small number of asthma sufferers.
