In a breakthrough that could transform pediatric cardiac care, researchers at Northwestern University have unveiled the world’s smallest pacemaker — a fully wireless, injectable, and dissolvable device that can provide temporary heart pacing without the need for surgery.
Roughly the size of a grain of rice, the innovative device measures just 1.8 mm wide, 3.5 mm long, and 1 mm thick. Designed specifically for newborns with congenital heart defects who require temporary pacing after surgery, this tiny marvel can be delivered via syringe, avoiding the need for invasive procedures typically associated with pacemaker implantation.
“The key advantage here is simplicity,” said Professor John Rogers, who led the development team. “Temporary pacemakers are essential during pediatric heart surgeries. This device simplifies the process and removes the need for a second surgery to extract it.”
Unlike conventional pacemakers, which rely on batteries and wires, this new device is powered by a galvanic cell. When it comes into contact with the body’s internal fluids, the cell activates and generates enough electrical energy to stimulate the heart. The absence of batteries and antennas contributes to the device’s ultracompact size and biocompatibility.
What truly sets this device apart, however, is its dissolvable design. Constructed from bioresorbable materials, the pacemaker naturally breaks down within the body once its job is done — typically after about one week. This eliminates the risk of infection, bleeding, or tissue damage associated with device retrieval, a significant concern especially in fragile pediatric patients.
The system also includes a soft, wearable patch that is placed on the patient’s chest. This patch continuously monitors the heart’s rhythms and communicates with the pacemaker via infrared light pulses. Whenever an irregular rhythm is detected, the patch activates the pacemaker through light-based signaling, replacing the traditional need for radiofrequency communication.
This optical activation system allows for even greater miniaturization of the implant, removing the need for onboard antennas and significantly reducing patient discomfort and risk.
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Initial trials in animal models and human donor hearts have shown promising results, with the pacemaker effectively adjusting to different heart sizes and conditions. These early tests validate its ability to pace the heart reliably in a range of physiological settings — from newborn hearts to adult donor tissue.
The findings, published in the journal Nature, underscore the potential for broader use cases beyond neonatal care. According to the research team, future applications could include temporary neurological stimulation, pain management, and accelerated wound healing, all of which could benefit from wireless, dissolvable bioelectronics.
The team has also launched a startup to pursue regulatory approvals and prepare for clinical trials, moving the technology closer to real-world use in hospitals.
“This is a leap forward not only for cardiac care but for the entire field of bioresorbable medical devices,” said Rogers. “It opens up possibilities for safer, less invasive post-operative treatments across a wide range of disciplines.”
The innovation comes at a crucial time. Temporary pacing is often necessary for infants recovering from cardiac surgery, but traditional pacemakers are poorly suited to such small and delicate bodies. Wires that exit the skin can introduce infection risks, while surgical retrieval of the device adds further complications.
This new device sidesteps those challenges entirely, representing what many in the field see as a paradigm shift in medical device design — where technology works quietly, efficiently, and then disappears once it’s no longer needed.
As clinical trials loom on the horizon, the medical community is watching closely. If successful in human studies, this pacemaker could be in hospitals within a few years, offering new hope to countless families and drastically improving outcomes for the tiniest of patients.
