A Tiny, Rice-Sized Pacemaker Can Biodegrade in Time, Helping Newborns

There is now a pacemaker smaller than a grain of rice that is designed to help the tiniest of hearts. Researchers from Northwestern University have successfully developed a pacemaker that fits in the tip of a syringe and can be inserted non-invasively into the hearts of newborn babies with congenital heart issues, according to a new study published in Nature. 

The pacemaker works with an external flexible chest piece that monitors the heart and sends a beam of light into the chest when it detects heart rhythm issues, triggering the pacemaker. This new, biodegradable device could save countless lives in the future. 

Developing the World’s Smallest Pacemaker 

According to Columbia University, the average size of a healthy newborn baby’s heart is that of a walnut. If there is an issue with the heart, it can be difficult for doctors to give the child the care they need, as traditional pacemakers can be roughly the same size and often need some form of surgery to be implanted. 

However, the device the Northwestern University researcher team has created will help mitigate the risks of surgery as it can be non-invasively implanted and will biodegrade after enough time has passed. 

“We have developed what is, to our knowledge, the world’s smallest pacemaker,” said John A. Rogers, a Northwestern bioelectronics pioneer who led the device development, in a press release. “There’s a crucial need for temporary pacemakers in the context of pediatric heart surgeries, and that’s a use case where size miniaturization is incredibly important. In terms of the device load on the body — the smaller, the better.”

The researcher team tested their model on rodents and organ donors from deceased individuals. The study findings indicate that the tiny device works on a variety of heart sizes, not just children’s, though researchers conducted the study with children in mind. 

Read More: It May be Possible to Power Implantable Generators with Our Bodies

Creating a Biodegradable Pacemaker 

The idea for the device came from previous research by Rogers and colleague Igor Efimov, who is the study co-author and professor of biomedical engineering and professor of medicine (cardiology) at Northwestern. 

In a previous study published in Nature Biotechnology, the duo worked on a different temporary pacemaker that was also biodegradable. According to the researchers, many people require pacemakers after they’ve had heart surgery to help get their hearts back into the right rhythm. These pacemakers often require wires that connect to the heart and can lead to a variety of issues when they are removed, such as infection, tissue damage, and blood clots. 

Designed for temporary pacing, the tiny pacemaker simply dissolves when it's no longer needed. By harmlessly degrading within the body, it bypasses the need for surgical extraction

“Wires literally protrude from the body, attached to a pacemaker outside the body,” Efimov said in a press release.

“When the pacemaker is no longer needed, a physician pulls it out. The wires can become enveloped in scar tissue. So, when the wires are pulled out, that can potentially damage the heart muscle. That’s actually how Neil Armstrong died. He had a temporary pacemaker after a bypass surgery. When the wires were removed, he experienced internal bleeding, “ Efimov added in a press release. 

The duo’s first biodegradable devices eliminated the need for wires that could cause damage, making pacemakers safer and more efficient. However, doctors wondered if their quarter-sized pacemaker could be made smaller so that it was less invasive to implant. 

Using the Body’s Energy 

To produce a smaller pacemaker, the duo had to rethink the device's power source. Their original device used near-field communication protocols, similar to what smartphones use for payment apps, and required an antenna. The antenna is what added extra space to the device. 

To reduce the size, the duo designed a light-based scheme that would turn the pacemaker on and create the pulses the heart needed. They also used a battery that could transform the body's chemical energy into electrical energy. 

“When the pacemaker is implanted into the body, the surrounding biofluids act as the conducting electrolyte that electrically joins those two metal pads to form the battery,” Rogers said in a press release. “A very tiny light-activated switch on the opposite side from the battery allows us to turn the device from its ‘off’ state to an ‘on’ state upon delivery of light that passes through the patient’s body from the skin-mounted patch.”

This new device could open an array of other doors when it comes to creating other non-invasive medical devices. Who knows what the future may hold with this technology? 

Read More: Pacemaker Powered By Light Eliminates Need For Batteries And Allows The Heart To Function More Naturally 

Article Sources

Our writers at Discovermagazine.com use peer-reviewed studies and high-quality sources for our articles, and our editors review for scientific accuracy and editorial standards. Review the sources used below for this article:

• Columbia University Department of Pediatrics. Caring for the Tiniest Hearts

• Nature. Millimetre-scale bioresorbable optoelectronic systems for electrotherapy

• Northwestern Now. First-ever transient pacemaker harmlessly dissolves in body

• Nature Biotechnology. Fully implantable and bioresorbable cardiac pacemakers without leads or batteries

A graduate of UW-Whitewater, Monica Cull wrote for several organizations, including one that focused on bees and the natural world, before coming to Discover Magazine. Her current work also appears on her travel blog and Common State Magazine. Her love of science came from watching PBS shows as a kid with her mom and spending too much time binging Doctor Who.