The University of California, Berkeley (UC Berkeley) engineers, in collaboration with University of California, San Francisco (UC San Francisco) researchers, have developed a new smart bandage.
The new bandage uses electrical currents to detect early tissue damage from pressure ulcers, or bedsores, before they can be viewed by human eyes.
UC Berkeley electrical engineering and computer sciences associate professor and smart-bandage project head Michel Maharbiz said: "We set out to create a type of bandage that could detect bedsores as they are forming, before the damage reaches the surface of the skin.
"We can imagine this being carried by a nurse for spot-checking target areas on a patient, or it could be incorporated into a wound dressing to regularly monitor how it’s healing."
The researchers examined the thin and non-invasive bandage on the skin of rats, observing that the device was able to detect varying degrees of tissue damage consistently across multiple animals.
The engineers printed an array of dozens of electrodes onto a thin and flexible film, and discharged small amount of current between the electrodes to develop a spatial map of the underlying tissue based upon the flow of electricity at different frequencies or otherwise called impedance spectroscopy.
They have observed that cell’s membrane is relatively impermeable when functioning properly and acted like an insulator to the cell’s conductive contents, while the integrity of the cell wall starts to break down when a cell starts to die, allowing electrical signals to leak through much like a resistor.
Next, the researchers gently squeezed the bare skin of rats between two magnets to mimic pressure wound and left the magnets in place for one or three hours while the rats resumed normal activity.
The smart bandage is said to detect changes in electrical resistance consistent with increased membrane permeability, a sign of a dying cell.
Image: The smart bandage is fabricated by printing gold electrodes onto a thin piece of plastic. Courtesy of 2015 UC Regents.