Tag: cardiac pacemaker

Biomedical Breakthroughs: “Biological” Pacemakers

biologicalpacemakersSince they were first developed some forty years ago, pacemakers have served an invaluable medical function. By stimulating the heart with electrical stimulation, they ensure that the recipients heart continues to beat at a steady rate. However, the implantation process calls for a major medical procedure, and the presence of the machine inside the body can lead to complications – i.e. infections.

Little wonder then why researchers are looking to create a better design to replace it with. However, up until now, proposed upgrades have focused on eliminating batteries (that require additional surgery to be replaced) with perpetual motion or piezeoelectric-powered devices. But this most recent proposal, which comes from the Cedars-Sinai Heart Institute in Los Angeles, looks to use the heart’s own cells to regulate it and keep it in working order.

piezoelectric-pacemakerIn an effort that was apparently the result of “dozens of years” worth of research, Dr. Eduardo Marbán and his research team used genes injected into the defective hearts of pigs to convert unspecialized heart cells into “biological pacemakers”. The pigs, all of which suffered from complete heart blocks, had the gene TBX18 injected into their hearts via what is described as a minimally invasive catheter procedure.

This caused some of the existing unspecialized cardiac cells to transform into sinuatrial node cells, which consist of tissue that initiates the electrical impulses that set the rhythm of the heart. The day after the procedure, the recipient pigs’ hearts were already beating faster than those of a control group and lasted for the duration of the 14-day study – indicating that the treatment could be a longer-term solution than previously thought.

biomedicineInitially, Marbán and his colleagues conceived of it more as a temporary fix for patients who were having problems with their man-made pacemakers. Now, they’re considering the possibility that it could be a long-term biological treatment. It could also be used on infants still in the womb, who can’t currently receive mechanical pacemakers. And while the research has so far been confined to pigs, human clinical studies could begin in as soon as three years.

In keeping with a trends in modern medicine, this gene therapy offers a potential third alternative to medical machiners and biomimetics. The one seeks to enhance the workings of our biological bodies through the addition of machinery while the other seeks to create machinery that mimics the bodies natural functions. But by simply programming the body to perform the role of machinery, we can cut out the middle man.

Sources: gizmag.com, cedars-sinai.edu

The Future of Medicine: Muscle-Powered Pacemaker

piezoelectric-pacemakerOver 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.

piezoelectric_nanogeneratorTo 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.

pacemaker3The 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.

heart_patchesAnd 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