Imagine a pacemaker so small it can be delivered by syringe – and then simply dissolves when it’s no longer needed. Thanks to pioneering research at Northwestern University in the US, that concept is now a reality.

Researchers have developed the world’s smallest pacemaker, designed especially for patients who only need temporary pacing – such as newborns with congenital heart defects recovering from surgery. About the size of a grain of rice, this new device could dramatically change the way temporary heart conditions are managed, and its potential reach extends far beyond paediatrics.

A Gentler, Smarter Approach to Temporary Pacing

Currently, temporary pacemakers are commonly used after heart surgery to stabilise the heart’s rhythm during recovery. However, the standard method involves sewing wires onto the heart and running them through the patient’s chest to connect to an external box. This approach can come with serious risks, including infection, scarring, or tissue damage when the wires are removed – complications that once contributed to the death of astronaut Neil Armstrong.

The new dissolvable pacemaker aims to eliminate those risks entirely.

Instead of wires and external hardware, this device is powered wirelessly and is fully biocompatible, meaning it can safely break down in the body over time. Once the heart no longer needs support, there’s no need for surgery to retrieve the pacemaker – it simply dissolves.

A Wearable That Talks to the Heart

Working alongside this tiny pacemaker is a soft, wireless wearable device that attaches to the patient’s chest. When it detects an irregular heartbeat, it emits a gentle pulse of infrared light through the skin, activating the pacemaker and regulating the heartbeat in real time.

This innovative light-based system replaces older antenna technology, which had previously limited the miniaturisation of pacemakers. Infrared light was chosen because of its ability to safely penetrate tissue, and the entire system has been designed to work even in the smallest and most fragile patients.

Powered by the Body

One of the most remarkable aspects of this device is how it’s powered. Using a galvanic cell, the pacemaker converts the body’s natural biofluids into energy. Two metal electrodes interact with the fluids, generating a current to keep the heart beating in rhythm. This chemical energy is then controlled by a light-activated switch – no bulky batteries or wires required.

Designed with Children in Mind

The technology has been carefully developed with infants in mind. Roughly 1% of children are born with congenital heart defects, many of whom need pacing support for just a few days following surgery. This new pacemaker can be placed directly on the heart and does its job without requiring additional procedures later – offering a less invasive and more compassionate option for babies and their families.

Dr Igor Efimov, co-lead of the research, noted:

“These children only need temporary pacing after surgery. In about seven days, most patients’ hearts will self-repair. But those seven days are absolutely critical.”

Beyond the Heart: A Broader Vision

Although initially designed for cardiac pacing, the researchers see wide-ranging applications for this bioelectronic technology. Its ability to deliver gentle stimulation in a programmable and dissolvable format could make it suitable for supporting nerve regeneration, pain management, wound healing, and more.

Professor John A. Rogers, lead developer, explained:

“Because it’s so small, this pacemaker can be integrated with almost any kind of implantable device.”

For example, the team has already explored how these devices could be embedded in transcatheter aortic valve replacements, where they could be activated if complications arise post-surgery – further reducing the need for invasive interventions.

Looking Ahead

The research, published in the journal Nature, is part of a growing field of bioresorbable electronics – devices that provide therapeutic benefit before safely dissolving inside the body. While still at the preclinical stage, this breakthrough points toward a future where medical implants are not only smarter and safer but also temporary, reducing the risks and stress associated with follow-up surgeries.

For patients, families, and healthcare systems, innovations like this could be truly life-changing.

Image credit: John A. Rogers/Northwestern University

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