“Our e-health patches may be employed as part of screening for lifestyle-related diseases such as heart disorders, signs of stress, and sleep apnea,” explains first author Dr. Andreas Petritz, in a statement.
The researchers used what’s known as a ferroelectric substance, which can power itself from normal movement — the piezoelectric effect. This is because the substance contains crystals that can be made to spontaneously have both a positive and negative charge. The researchers applied a strong electric current to a small amount of the material, just one micron thick. The material was very efficient at converting natural motion into small electric voltages, the researchers found.
These currents could either be transformed into signals for medical sensors or used to harvest energy. Multilayer patches could harvest up to 200 millijoules per day from a person’s natural movement if placed on a joint, like knees and elbows, the researchers say. This is enough power to monitor a patient’s cardiovascular parameters several times a day.
Also, because the patches are so thin, they are barely visible, making daily health monitors less invasive and unpleasant. “We expect that our findings will assist in the development of other sheet-type sensor systems that can perform precise bio-monitoring when affixed to the skin surface,” says study senior author Professor Tsuyoshi Sekitani.
The technology could even be monitored via smartphone or computer, the authors say.