Biomedical power source harvests energy from soundwaves in body
Image credit: Dreamstime
A new material allows bioelectronic implants to be charged ultrasonically through human skin and could eliminate the need for invasive procedures to change the batteries in devices such as pacemakers (pictured).
Researchers from the King Abdullah University of Science and Technology (KAUST) believe that hydrogels - long polymer molecules cross-linked to form a three-dimensional network – can be turned into little electricity generators by absorbing soundwaves that pass through the human body.
Electronic devices are increasingly used to remedy serious and long-term health problems, such as pacemakers to regulate heartbeat, electronic pumps that release insulin and implantable hearing aids.
They are typically designed to be minimally sized and weighted for patient comfort and are nontoxic to the body.
Powering such devices is often a design hurdle and minimising the need for external procedures – such as an operation to change the battery – can improve patient outcomes.
Hydrogels, which can hold a considerable amount of water in them and conduct electricity, have a flexible and stretchable texture that is ideal for use in the human body.
The research team combined polyvinyl alcohol with nanosheets of MXene, a transition-metal carbide, to create M-gel.
“Just as dissolving salt in water makes it conductive, we used MXene nanoflakes to create the hydrogel,” said lead author Kanghyuck Lee. “We were surprised to find that the resulting material can generate electric power under the influence of ultrasound waves.”
M-gel generates a current when an applied pressure forces the flow of electrical ions in the water, filling the hydrogel. When this pressure is the result of ultrasound, the effect is called streaming vibration potential.
The KAUST team proved the concept by using a range of ultrasonic sources, including ultrasound tips found in many labs and the ultrasound probes used in hospitals for imaging. They were able to quickly charge an electrical device buried within several centimetres of beef.
“This is another example of the impressive potential of MXene hydrogels we’ve been developing in our laboratory for sensing and energy applications,” said researcher Husam Alshareef.
In February, an American team demonstrated a wearable sensor that could help doctors remotely detect critical changes in heart failure patients before a health crisis occurs in order to prevent hospitalisation.
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