Engineers at Northwestern University have developed the world’s smallest pacemaker, a bioresorbable device that can be injected with a syringe and dissolves harmlessly inside the body after its job is done.
Smaller than a grain of rice, this ultra-miniature pacemaker is designed for temporary heart pacing, particularly in infants born with congenital heart defects. The innovation is being hailed as a game-changer in pediatric cardiac care, offering a non-invasive and safe alternative to traditional pacemakers that often require complex surgeries.
Measuring only 1.8 millimetres wide, 3.5 millimetres long, and 1 millimetre thick, this device is 100 times smaller than conventional pacemakers. Despite its size, it can deliver powerful electrical pulses needed to keep the heart beating rhythmically.
“This is, to our knowledge, the smallest pacemaker ever developed,” said Professor John A. Rogers, a bioelectronics expert who co-led the research. “The size is especially critical for babies recovering from heart surgery. The smaller and less invasive the device, the better it is for the patient.”
Unlike conventional pacemakers that require wires and batteries, this device operates without a battery. Instead, it works as a tiny galvanic cell, using metal electrodes and the body’s natural fluids to generate electricity.
John A. Rogers/Northwestern University
Attached to the chest via a flexible, wireless wearable patch, the system uses infrared light to control the device. If a patient’s heart rate drops too low, the patch detects the problem and emits a pulse of light that passes through the skin, activating the pacemaker.
This light-triggered activation eliminates the need for near-field communication systems, making the device even more compact and reliable.
Each year, about 1% of newborns are born with congenital heart defects. While many require only temporary heart pacing after surgery, current devices involve open-chest procedures and removal surgeries, which carry added risks.
“This tiny pacemaker changes everything,” said Dr. Igor Efimov, a cardiologist and co-author of the study. “Now we can implant it during surgery, and it dissolves naturally once it’s no longer needed. No second surgery. No trauma. Just smart technology doing its job.”
The pacemaker is expected to support newborns for up to seven days after surgery, giving their hearts time to heal and regain natural rhythm. While this invention primarily targets pediatric heart care, the researchers believe it could revolutionize other areas of medicine too.
“We can implant multiple devices around the heart, each activated by different colored lights,” explained Prof. Rogers. “This could help treat arrhythmias or other irregular heart rhythms in adults and children alike.”
The team sees potential uses in nerve stimulation, pain relief, wound healing, and even bone recovery. This breakthrough represents the next step in bioresorbable medical electronics, a field focused on temporary, dissolvable devices that perform their functions and then vanish without leaving harmful residues.
“The heart only needs a small amount of electrical stimulation,” Rogers said. “By making this device so tiny, we’re not only reducing surgical trauma, we’re also cutting down on hospital costs and improving recovery outcomes.”
The research, titled “Millimetre-scale, bioresorbable optoelectronic systems for electrotherapy”, was published in the journal Nature. It highlights not just the device’s technical brilliance but also its life-saving potential for vulnerable patients.
While still in the early stages of clinical development, this device could soon reshape global standards in temporary cardiac care. It’s especially promising for low-resource countries, where advanced surgical tools are limited.
“With this kind of device, we can offer advanced care to newborns across the world, regardless of their geographic or economic situation,” Dr. Efimov emphasized.
