Wireless Health Monitoring Using Integrated and Stretchable Electronics

one month ago by Luke James

The wireless, wearable adhesive-free monitor with integrated stretchable electronics could facilitate comfortable, long-term health monitoring without the risks of skin irritation, injury, or allergic reactions that current adhesive sensors carry.

The 75mm stick-on device uses three electrodes to pick up signals and monitor and broadcast electrocardiogram (ECG), respiratory rate, heart rate, and motion activity data and send it up to 15 meters away to a portable recording device (e.g. a smartphone). 

It is thought that this device could pave the way for more comfortable, long-term health monitoring, particularly in babies and children who are prone to constant moving. Assistant Professor Woon-Hong Yeo from the George W. Woodruff School of Mechanical Engineering said that the device "…is designed to meet the electronic health monitoring needs of people whose sensitive skin may be harmed by conventional monitors."

 

Vital signs and data can be monitored via an Android app. Image courtesy of WILEY-VCH.

 

The device's research was supported by the Imlay Innovation Fund at Children's Healthcare of Atlanta, NextFlex, and a seed grant from the Institute for Electronics and Nanotechnology at Georgia Tech. 

In vivo demonstrations with both humans and animals have already demonstrated the overall suitability and versatility for the device as both a health monitor and research tool.

How Does the Device Differ from Current Adhesive Monitors?

It all comes down to Georgia Tech's stretchable monitor being able to conform to the skin. Because it does this, it avoids signal disruptions and other issues that are caused by the motion of conventional metal-gel electrodes across the skin. 

Georgia Tech's device is even able to capture and maintain accurate readings and signals when the end-user is moving or participating in more strenuous activities such as climbing stairs or running. This makes the device particularly suitable for use with those who are prone to a lot of movement such as babies and children.

 

Circuit design. Image courtesy of WILEY-VCH.

 

With conventional electrodes, movement creates motion signals that can be difficult to differentiate from those that you want to measure. 

The soft and conformal nature of the stretchable monitor means that it moves with the skin, not against it, and provides information and data that cannot be measured due to the motion signals produced by conventional sensors. 

 

Device Use Cases

In the home, the device can be used to detect problems and changes that may not be apparent in a physician's surgery or hospital point-in-time. Long-term monitoring in the home is beneficial because it helps build a bigger picture for better diagnostics and treatment.

In clinical settings, the device aids the logistical side of things—there is no need for healthcare staff to constantly be hooking and unhooking the patient as is the case with wired systems, and the wireless nature of the device could make vulnerable patients, e.g. children or the elderly, feel less tied to equipment, something which can be nerve-wracking. This improves the overall quality of care and aids recovery. 

It is built to be long-lasting, too. It can be worn for multiple days, perhaps up to two weeks, which is much longer than current sensors. It is waterproof, too, and 100% recyclable.

How the Device Works

Two versions of the monitor have been designed and developed. The first is designed for short-term use in care facilities and is based on tape whereas the other, the one we are focussing on, is designed for long-term use and is created with an elastomer film. 

The device's assembly process is made up of four phases:

  1. Fabrication of the thin-film circuit and nanomembrane electrodes;

  2. Transfer of the thin-film structure to elastomeric substrates;

  3. Circuit assembly by soldering; and

  4. Electrode connection, elastomer encapsulation, and magnet installation.

Standard microfabrication is used to construct the stretchable polymer/metal composite structure and reflow soldering is used alongside surface mount chip components for circuit assembly. 

 

Assembly chart of electrodes and circuit and connector fabrication

A figure detailing electrodes, circuit, and connector fabrication assembly. Image courtesy of WILEY-VCH.

 

The primary advantage of the device is that it removes the need for conductive gels and adhesives. Instead, the device contours with the skin with the use of Au/PI electrodes with a thickness of only 1.2µm whilst being able to deform and reattach as movement occurs. 

Whilst attached to the skin, the sensor can generate clinical-grade ECG results and accurate analysis of previously mentioned vital signs, and the motion sensor assesses and measures physical activities. Using convolutional neural networks, it delivers real-time multifaceted analysis with clinical relevance. 

 

A Powerful Assistant to the Practice of Medicine

By offering smart, real-time ambulatory monitoring, the SHE device becomes desirable in settings where minimal patient impact needs to be achieved in terms of condition and lifestyle. 

By making wearable medical devices comfortable, long-lasting, and hassle-free, this clever device and all those that follow it will become a priceless tool in healthcare at a time when continuous monitoring and data gathering need to be achieved without sacrifice to patients.

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