Scientists at Northwestern University have developed the world’s smallest pacemaker that can fit inside the tip of a syringe and be non-invasively injected into the body. Measuring just 1.8 millimetres in width, 3.5 millimetres in length and one millimetre in thickness, the tiny device is smaller than a grain of rice but still manages to deliver as much stimulation as a full-sized pacemaker.
The device can work with hearts of all sizes but engineers who developed it say it is particularly well-suited to tiny, fragile hearts of newborn babies with congenital heart defects.
“We have developed what is, to our knowledge, the world’s smallest pacemaker,” said Northwestern bioelectronics pioneer John A Rogers, who led the device’s development.
“There’s a crucial need for temporary pacemakers in the context of pediatric heart surgeries, and that’s a use case where size miniaturisation is incredibly important. In terms of the device load on the body – the smaller, the better.”
Check out some brand new biomedical tech – crazy cool, in my own, humble but admittedly biased opinion – introduced in our paper (link below), published today in @Nature, titled “Millimetre-scale, bioresorbable optoelectronic systems for electrotherapy,” where we describe the… pic.twitter.com/fqf9GZTsTY
— John A Rogers (@ProfJohnARogers) April 2, 2025
How does the device work?
Currently, temporary pacemakers require surgery to sew electrodes onto heart muscles with wires connecting to a powered device on the patient’s chest. When the device is no longer required, the doctors pull out the wires, which can sometimes cause damage.
However, the newly developed pacemaker is wireless and has been designed to dissolve into the body when no longer needed. Instead of using near-field communication to supply power, the tiny pacemaker operates through the action of a galvanic cell, a type of simple battery that transforms chemical energy into electrical energy.
When in contact with surrounding biofluids, the electrodes form a battery. The resulting chemical reactions cause the electrical current to flow to stimulate the heart.
The pacemaker is attached to a soft patch worn on the patient’s chest. The team used an infrared wavelength of light that penetrates deeply and safely into the body.
“If the patient’s heart rate drops below a certain rate, the wearable device detects the event and automatically activates a light-emitting diode. The light then flashes on and off at a rate that corresponds to the normal heart rate.”
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The US-led team of researchers behind the new device said they were motivated to help the small minority of children born with congenital heart defects.
“Our main focus was children. Around one per cent are born with congenital heart defects, but most only need temporary pacing after surgery. In about seven days, their hearts self-repair,” said Northwestern cardiologist Igor Efimov.
“This tiny pacemaker can support them during that critical period, without requiring another surgery for removal.”
Source:: https://www.ndtv.com/science/worlds-tiniest-pacemaker-smaller-than-grain-of-rice-developed-8083497