Over the past few decades, cardiac pacemakers have improved to the point that they have become a commonplace medical implant that have helped improve or save the lives of millions around the world. Unfortunately, the battery technology that is used to power these devices has not kept pace. Every seven years they need to be replaced, a process which requires further surgery.
To address this problem, a group of researchers from Korea Advanced Institute of Science and Technology (KAIST) has developed a cardiac pacemaker that is powered by harnessing energy from the body’s own muscles. The research team, headed by Professor Keon Jae Lee of KAIST and Professor Boyoung Joung, M.D. at Severance Hospital of Yonsei University, has created a flexible piezoelectric nanogenerator can keep a pacemaker running almost indefinitely.
To test the device, Lee, Joung and their research team implanted the pacemaker into a live rat and watched as it produced electrical energy using nothing but small body movements. Based on earlier experiments with piezoelectric generator technology used by KAIST to produce a low-cost, large area version, the team created their new high-performance flexible nanogenerator from a thin film semiconductor material.
In this case, lead magnesium niobate-lead titanate (PMN-PT) was used rather than the graphene oxide and carbon nanotubes of previous versions. As a result, the new device was able to harvest up to 8.2 V and 0.22 mA of electrical energy as a result of small flexing motions of the nanogenerator. This voltage was sufficient enough to stimulate the rat’s heart directly.
The direct benefit of this experimental technology could be in the production and use of self-powered flexible energy generators that could increase the life of cardiac pacemakers, reduce the risks associated with repeated surgeries to replace pacemaker batteries, and even provide a way to power other implanted medical monitoring devices. As Professor Keon Jae Lee explains:
For clinical purposes, the current achievement will benefit the development of self-powered cardiac pacemakers as well as prevent heart attacks via the real-time diagnosis of heart arrhythmia. In addition, the flexible piezoelectric nanogenerator could also be utilized as an electrical source for various implantable medical devices.
Other self-powering experimental technologies for cardiac pacemakers have sought to provide energy from the beating of the heart itself, or from external sources, such as in light-controlled non-viral optogenetics.But the KAIST pacemaker appears to be the first practical version to demonstrate real promise in living laboratory animals and, with any luck, human patients in the not-too-distant future.
And while this does represent a major step forward in the field of piezoelectrics – a technology that could power everything from personal devices to entire communities by harnessing kinetic energy – it is also a boon for non-invasive medicine and energy self-sufficiency.
And be sure to check out this video of the pacemaker at work, courtesy of KAIST and the Severance Hospital of Yonsei University:
Sources: gizmag.com, circep.ahajournals.org, kaist.edu