A Soft Wearable Ultrasound Sensor Peers Deep Under Your Skin to Monitor Muscles and More
Designed for comfort, this tiny patch can look 1.6 inches beneath your skin and create a 3D image of what it finds.
Researchers from the University of California San Diego, the University of Pennsylvania, the University of Southern California, University Medical Center Hamburg-Eppendorf, the University of Toronto, and the University of Southern California have developed a soft, stretchable ultrasonic array which can be worn to offer a view of what's going on over an inch and a half deep into the wearer's skin — entirely non-invasively.
"We invented a wearable device that can frequently evaluate the stiffness of human tissue," explains Hongjie Hu, postdoctoral researcher and co-author of the paper detailing the team's work. "In particular, we integrated an array of ultrasound elements into a soft elastomer matrix and used wavy serpentine stretchable electrodes to connect these elements, enabling the device to conform to human skin for serial assessment of tissue stiffness."
The resulting device, known as an elastography monitor, can make repeated measurements up to 4cm (around 1.6") deep with a spatial resolution of 0.5mm (around 0.02"). This, the researchers claim, has real potential for monitoring and diagnosing a range of illnesses, from sports injuries to muscles, tendons, and ligaments to fibrosis and cirrhosis of the liver, tendonitis, and arterial wall elasticity. The same device can also be used in medical research involving the monitoring of disease progress, in particular cancer.
The patch itself, built using a low-temperature process, is based on a flexible 16×16 array of ultrasonic transducers on a flexible substrate, with each transducer made up of seven-layer electrodes with a silver-epoxy composite backing layer to absorb unwanted vibrations. The entire patch is soft, adheres well to the skin, and can be stretched by up to 40 per cent to help it conform to uneven surfaces — while a calibration layer can be added to read absolute, rather than relative, values.
"This new wave of wearable ultrasound technology is driving a transformation in the healthcare monitoring field, improving patient outcomes, reducing healthcare costs, and promoting the widespread adoption of point-of-care diagnosis," claims co-author Yuxiang Ma. "As this technology continues to develop, it is likely that we will see even more significant advances in the field of medical imaging and healthcare monitoring."
The team's work has been published in the journal Nature Biomedical Engineering under open-access terms.