A self-sustaining pacemaker
How to save implantable devices from the need to replace batteries?
Alexander Berezin, Compulenta
John Rogers, already known to you (see the articles "Implantable silk–based microcircuits" and "LEDs for injection" - VM), together with colleagues from the University of Illinois at Urbana and Champaign (USA), used lead zirconate titanate, capable of generating an electric current when pressure is applied to it, for application to flexible biocompatible silicone tape that can change shape according to the shape of the moving organ.
Piezoelectric tape attached to the heart of the operated cow
(photo by University of Illinois, University of Arizona).
Attaching a rechargeable battery to such a device, the entire system was implanted into several animals, using not only the heart, but also the lungs with a diaphragm to receive current.
"The concept of generating electricity from the movement of internal organs is really interesting," says Mr. Rogers. And it's like this: modern implantable devices are powered by batteries. And when their charge comes to an end, the patient is forced to wait for surgery, before which the same pacemakers switch to a "simplified" mode of regulation of heart rate, which forces a person to say "no" to an active lifestyle before replacing the batteries.
But won't receiving energy from the same heart harm its functions? As it turned out, when the silicone tape is positioned at an angle to the ventricles, it does not interfere with the heart in any way, and the total energy consumption of this organ is such that against their background, the insignificant energy taken by the tape and piezoelectric does not affect anything at all.
The current system generates approximately 0.2 MW per square centimeter of piezoelectric material, which, although sufficient to power any of the implantable pacemakers on the market, is still small in comparison with the general energy needs of the body directed to heart contractions.
It is emphasized that the system has been tested on animals comparable in size to humans, including cows, sheep and our almost identical pigs. If the long part of the experiment – monitoring the vital activity of animals with implanted piezoelectrics – shows a complete absence of negative effects on them, then the next step will be the use of similar systems for medical implants.
The research report is published in the journal Proceedings of the National Academy of Sciences (Dagdeviren et al., Conformal piezoelectric energy harvesting and storage from motives of the heart, lung, and diaphragm).
Prepared by NewScientist: Bendy implant harnesses the power of your beating heart.
Portal "Eternal youth" http://vechnayamolodost.ru22.01.2014