Image Credentials: Image Title: World’s Smallest Light-Activated Pacemaker Offers Revolutionary Solution for Pediatric Cardiac Care Source: AI-Generated Image (DALL-E) Date: April 2025 Attribution: Created by AI-generated imagery (DALL-E), and it does not depict a real-world scene.
By Staff Writer
Source: Northwestern University
Published in: Nature
Abstract:
Northwestern University engineers have developed the world’s smallest pacemaker, a groundbreaking advancement in bioelectronics designed to deliver temporary pacing through light activation. Measuring smaller than a grain of rice, this millimeter-scale, bioresorbable device is especially suited for the delicate hearts of newborns with congenital heart defects. The fully dissolvable device eliminates the risks associated with traditional pacemaker removal, offering a safer, less invasive, and more adaptable solution for critical care.
Introduction
Temporary cardiac pacing is essential for many patients recovering from surgery or dealing with congenital heart defects, particularly in neonates. Current pacemaker systems rely on invasive procedures, bulky devices, and follow-up surgeries for removal. The newly developed light-activated, dissolvable pacemaker offers a pioneering alternative, combining miniaturized hardware, wireless control, and complete bioresorption to reduce patient trauma and streamline recovery.
Device Overview and Functionality
Developed by a multidisciplinary team led by John A. Rogers, Igor Efimov, and Yonggang Huang, the pacemaker operates using a light-based control system paired with a galvanic cell-based biofluid-powered battery. Measuring just 1.8 mm x 3.5 mm x 1 mm, the device can be injected directly into the heart via syringe, eliminating the need for surgical implantation.
The tiniest ever, bioresorbable pacemaker, activated wirelessly by light, and its potential as a platform for electrotherapyhttps://t.co/Vvr1SiojEV @Nature @NorthwesternEng pic.twitter.com/YX52wAJuOq
— Eric Topol (@EricTopol) April 2, 2025
A soft, wearable patch affixed to the patient’s chest monitors heart rhythms and activates the pacemaker using infrared light pulses. These pulses safely penetrate the skin, muscles, and breastbone, delivering stimulation when abnormal rhythms are detected. Once no longer needed, the device harmlessly dissolves into body fluids, erasing the need for extraction.
Clinical Motivation and Pediatric Application
Approximately 1% of newborns are born with congenital heart defects requiring temporary pacing. Traditional systems pose risks of infection, scarring, and damage during wire extraction. In contrast, the new pacemaker presents a minimally invasive, wire-free alternative. It offers a gentle, non-disruptive pacing solution for neonates, ensuring safe cardiac stimulation during the critical postoperative window — typically around seven days.
“Our major motivation was children,” said Efimov. “Now, we can place this tiny pacemaker on a child’s heart and stimulate it with a soft, wearable device. No additional surgery is necessary.”
Innovations in Power and Control
One of the most significant challenges in miniaturizing pacemakers has been the power source. Traditional bioresorbable pacemakers used near-field communication, requiring large antennae. The new device eliminates this limitation by using biofluid-activated galvanic cells. Two metal electrodes react with the body’s natural fluids to generate electrical currents for pacing.
A light-sensitive switch enables activation only when exposed to infrared light, ensuring precision control without the need for embedded electronics or external wires.
Advanced Applications and Synchronization
The device’s miniaturization enables distributed deployment across the heart. Multiple devices can be independently activated using different wavelengths of light, offering sophisticated synchronization patterns for arrhythmia treatment or complex heart pacing strategies.
Additionally, the tiny pacemakers can be integrated into other implants, such as transcatheter aortic valve replacements, enhancing recovery and preventing rhythm disorders post-surgery.
Broader Implications for Bioelectronic Medicine
The dissolvable pacemaker is part of a larger push toward transient bioelectronics, a field pioneered by Rogers’ lab. Potential future applications include:
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Neural stimulation
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Wound healing enhancement
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Pain modulation
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Bone regeneration
By merging biocompatibility, miniaturization, and precision control, the device represents a paradigm shift in how temporary bioelectronic therapies are designed and delivered.
Conclusion
The light-activated, bioresorbable pacemaker is a significant breakthrough in pediatric cardiology and bioelectronic medicine. Its safe, non-invasive deployment, minimal size, and natural dissolution after use mark a new era for temporary implants. As the technology evolves, it promises wide-ranging applications in medical therapy and rehabilitation, setting a new standard for safe, responsive, and patient-centric care.
Study Title: Millimeter-scale, bioresorbable optoelectronic systems for electrotherapy
Published In: Nature, April 2025
Funding: Querrey Simpson Institute for Bioelectronics, Leducq Foundation, NIH (R01 HL141470)
Story Source:
Materials provided by Northwestern University. Original written by Amanda Morris. Note: Content may be edited for style and length.
Journal Reference:
- Zhang, Y., Rytkin, E., Zeng, L. et al. Millimetre-scale bioresorbable optoelectronic systems for electrotherapy. Nature, 2025 DOI: 10.1038/s41586-025-08726-4