Soft portable health monitor uses expandable electronics

A portable wireless monitor, built with expandable electronics, could provide comfortable, long-term monitoring of the health of adults, babies and small children without worrying about skin wounds or allergic reactions caused by conventional adhesive sensors with conductive gels.

The flexible and adaptable monitor can transmit up to 15 meters of electrocardiogram (ECG) data, heart rate, respiratory rate and motion activity to a portable recording device such as than a smartphone or tablet. The electronic components are mounted on an expandable substrate and connected to golden skin-shaped electrodes by means of printed connectors that can stretch with the medical film in which they are embedded.

"This health monitor has a key benefit for young children who are constantly moving because the compliant flexible device can accommodate this activity with a gentle integration on the skin," said Woon-Hong Yeo, badistant professor at George W. Woodruff School. Mechanical Engineering and Wallace H. Coulter Department of Biomedical Engineering at the Georgia Institute of Technology. "This is designed to meet the electronic health monitoring needs of people whose sensitive skin can be damaged by conventional monitors."

The details of the monitor were reported on July 24 in the newspaper Advanced Science. The research was funded by the Imlay Innovation Fund of the Children & # 39; s Healthcare Atlanta, NextFlex (Flexible Hybrid Electronics Manufacturing Institute), and by a start-up grant from the company. 39; Georgia Tech Institute of Electronics and Nanotechnology. The monitor has been studied on animal and human models.

Because the device conforms to the skin, it avoids the signal problems that can be created by the movement of typical metal-gel electrodes on the skin. The device can even get accurate signals from a person walking, running or climbing a staircase.

"When you put a conventional electrode on your chest, sitting or walking creates motion artifacts that are difficult to separate from the signals you want to measure," he said. "Because our device is soft and compliant, it moves with the skin and provides information that can not be seen with the motion artifacts of conventional sensors."

Continuous badessment with a wireless health monitor could improve the badessment of children and help clinicians identify trends earlier, potentially facilitating intervention before the disease progresses, said Dr. Kevin Maher, Pediatric Cardiologist at Children & # 39; s Healthcare of Atlanta.

"The generation of continuous data from the respiratory and cardiovascular systems could allow the application of advanced diagnostics to detect changes in clinical status, response to treatments and the implementation of early intervention" said Maher. "A device that literally tracks every breath of a child could allow early recognition and intervention before the onset of a more serious illness."

Used at home, a portable monitor could detect changes that otherwise would not be apparent, he said. In a clinical setting, the wireless device could allow children to feel less attached to the equipment. "I see this device as a significant change in pediatric health care and I'm excited to be working with Georgia Tech on the project," added Maher.

The monitor uses three gold electrodes embedded in the film that also contains the electronic processing equipment. The complete health monitor is only three inches in diameter and a more advanced version under development will be twice as small. The wireless monitor is now powered by a small rechargeable battery, but future versions may replace the battery with an external radio frequency charging system.

Yeo and his collaborators, including Yun-Soung Kim, lead author and postdoctoral researcher, focus on applications in pediatrics due to the need for outpatient monitoring in children. However, they are considering that the health monitor could also be used for other groups of patients, including older adults who may also have sensitive skin. For adults, there would be additional benefits.

"The monitor could be worn for days or even two weeks," Yeo said. "The membrane is waterproof, an adult can take a shower while wearing it.After use, electronic components can be recycled."

Two versions of the monitor have been developed. One is based on medical tape and designed for short-term use in a hospital or other care facility, while the other uses a flexible elastomeric medical film approved for the treatment of wounds. . The latter may stay on the skin longer.

"The devices are completely dry and do not require gel to pick up the signals from the skin," Yeo explained. "There is nothing between the skin and the ultra-thin sensor, so it's nice to wear."

Since the monitor can be worn for long periods, it can provide a long-term recording of ECG data useful for understanding potential heart problems. "We use in-depth learning to monitor the signals while comparing them to data from a larger group of patients," Yeo said. "If a fault is detected, it can be reported wirelessly via a smartphone or other connected device."

The manufacture of the monitor circuitry uses mesh-like copper mesh patterns that can flex with the flexible substrate. Chips are the only non-flexible part, but they are mounted on a flexible substrate isolated from the stresses instead of a traditional plastic printed circuit board.

In the next steps, Yeo plans to reduce the size of the device and add features to measure other parameters related to health, such as temperature, oxygen blood and blood pressure. A major milestone would be a clinical trial to evaluate performance compared to conventional health monitors.

For Yeo, a specialist in nanotechnology and microengineering, the ability to see the device during clinical trials – and ultimately used in children's hospitals – is a powerful incentive.

"It will be a dream come true for me to see something that we have developed to be helpful to someone who is suffering," he said. "We all want progress in science and engineering to translate into improved patient care."