Bedsores are more than a pain in the backside for bedridden folk, they can develop into dangerous infections and heighten the chances of a patient dying. While swollen ulcers on the skin are a pretty sure sign of their presence, by this point it is often too late for some of their effects to be reversed. But a team of researchers have developed what could function as an early warning system, a smart bandage containing flexible electronics that detects tissue damage before it becomes visible on the surface of the skin.
Using a technique known as impedance spectroscopy, the team of engineers at UC Berkeley set out to explore the electrical changes in tissue as it goes from a healthy to an unhealthy state. This saw a web of electrodes printed onto a thin film and loaded with a small electric current. Because in healthy cells the membrane is more or less sealed, and in a dying cell the membrane breaks down, letting the electric charge through, the thinking was that the flow of electricity at different frequencies could provide something of a spatial map indicative of unhealthy tissue.
Testing this bandage on rats, the team first replicated the effects of a bedsore by squeezing the bare skin between two magnets. They then applied the smart bandage to monitor the skin, which was inflamed and showed signs of oxidative damage. The researchers reported that the smart bandage detected changes in electrical resistance aligning with an increase in the permeability of the membrane, or signs of the dying cells.
"Our device is a comprehensive demonstration that tissue health in a living organism can be locally mapped using impedance spectroscopy," says the study's lead author Sarah Swisher, a Ph.D. candidate in electrical engineering and computer sciences at UC Berkeley.
In recent years, we have seen a number of solutions emerge aimed at preventing bedsores. Whereas hospital staff are generally required to turn at-risk patients over in their beds, ideas like the Intelligent bed would flip them over on its own. We have also seen "dot matrix" bed linen designed to lessen contact between the sheets and the skin, and a MAP System that provides real-time images of a body's pressure points.
But the UC Berkeley researchers are hopeful that the smart bandage will do more than prevent nasty and dangerous pressure wounds. They say using impedance spectroscopy in this way could offer new insights into how unhealthy tissue is formed and lead to improved patient care.
"One of the things that makes this work novel is that we took a comprehensive approach to understanding how the technique could be used to observe developing wounds in complex tissue," says Swisher. "In the past, people have used impedance spectroscopy for cell cultures or relatively simple measurements in tissue. What makes this unique is extending that to detect and extract useful information from wounds developing in the body. That’s a big leap."
The research was published in the journal Nature Communications.
Michel Maharbiz, a UC Berkeley associate professor of electrical engineering and computer sciences and head of the smart-bandage project explains the technology in the video below.
Source: UC Berkeley