Engineers from Dartmouth College have created a tiny device that could allow implanted biomedical devices to be charged indefinitely using the natural kinetic energy of the heart.
The heart's motion is so powerful that it can recharge devices that save our lives, according to new research from Dartmouth College. Where scientists have developed a dime-sized device to capture and convert the kinetic energy of the heart into electricity.
Implants such as pacemakers and defibrillators are powered by batteries that require replacement every five to ten years. The replacement surgeries are costly and could lead to complications and infections.
Over one million people have pacemakers, defibrillators and other live-saving implantable devices installed each year, All of those devices will need to have their batteries replaced every five to 10 years. Those replacements require surgery which can be costly, use valuable hospital resources (doctors, support staff, ward space) and create the possibility of complications and infections.
"We're trying to solve the ultimate problem for any implantable biomedical device," says Dartmouth engineering professor John X.J. Zhang, a lead researcher on the study his team completed alongside clinicians at the University of Texas in San Antonio.
"How do you create an effective energy source so the device will do its job during the entire life span of the patient, without the need for surgery to replace the battery?"
"Of equal importance is that the device not interfere with the body's function," adds Dartmouth research associate Lin Dong, first author on the paper.
"We knew it had to be bio-compatible, lightweight, flexible, and low profile, so it not only fits into the current pacemaker structure but is also scaleable for future multi-functionality."
An implanted piezoelectric patch gathers voltage produced by anaesthetised sheep. | Credit: University of Illinois and University of Arizona
The team's work proposes modifying pacemakers to harness the kinetic energy of the lead wire that's attached to the heart, converting it into electricity to continually charge the batteries. The added material is a type of thin polymer piezoelectric film called "PVDF" and, when designed with porous structures -- either an array of small buckle beams or a flexible cantilever -- it can convert even small mechanical motion to electricity. An added benefit: the same modules could potentially be used as sensors to enable data collection for real-time monitoring of patients.
Piezoelectricity is mechanical stress converted into electricity. Pressure, sound waves, and other vibrations coming into contact with piezoelectric materials cause the materials’ atoms to shift, creating positive and negative charges.
The invention utilises moving heart tissue that squeezes a flexible container with piezoelectric material inside, creating charges which are sent through the pacemaker’s lead wire back to its battery.
This continuous charging cycle, in theory, would enable any biomedical implant where motion was a component of the device’s location to last for the lifetime of a patient.
The results of the three-year study, completed by Dartmouth's engineering researchers along with clinicians at UT Health San Antonio, were just published in the cover story for Advanced Materials Technologies.
The two remaining years of NIH funding plus time to finish the pre-clinical process and obtain regulatory approval puts a self-charging pacemaker approximately five years out from commercialisation, according to Zhang.
"We've completed the first round of animal studies with great results which will be published soon," says Zhang. "There is already a lot of expressed interest from the major medical technology companies, and Andrew Closson, one of the study's authors working with Lin Dong and an engineering PhD Innovation Program student at Dartmouth, is learning the business and technology transfer skills to be a cohort in moving forward with the entrepreneurial phase of this effort."
What is a Pacemaker?
A pacemaker is a small electrical device, fitted in the chest or abdomen. It's used to treat some abnormal heart rhythms (arrhythmias) that can cause your heart to either beat too slowly or miss beats. Some pacemakers can also help the chambers of your heart beat in time.
The pacemaker sends electrical pulses to your heart to keep it beating regularly and not too slowly.Having a pacemaker can significantly improve your quality of life if you have problems with a slow heart rate. The device can be lifesaving for some people.
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