Metal-Free Implantable Magnetic Sensor Monitors the Heart Without Batteries
University of North Carolina researchers have created a biocompatible, metal-free magnetic patch that wirelessly tracks heart function for weeks before safely dissolving in the body, published in Nature Materials.
A research team led by Wubin Bai at the University of North Carolina has developed a fully biodegradable, metal-free magnetic sensor that can be implanted in the body, transmit wireless signals, and then dissolve harmlessly once its job is done. The key breakthrough was treating carbon nitride at several hundred degrees Celsius: heating drives off nitrogen atoms and restructures the material's electron arrangement, creating strong coupling between unpaired electrons that allows the material to maintain magnetism even after external magnetic fields are removed — a property normally only found in metal-containing magnets. The team shaped the heat-treated material into a flower-shaped patch and combined it with biodegradable polymer and silk protein. In pig studies, the implant successfully monitored cardiac function continuously for four weeks, with readings matching the accuracy of standard ultrasound. No battery, wires, or surgical removal were needed; the device transmitted wirelessly and eventually degraded into non-toxic molecules. Bai said the technology could ultimately help doctors monitor patient recovery after a heart attack or surgery more continuously than current methods allow. The findings were published in Nature Materials in October 2026 and are seen as a significant step toward a new class of 'disappearing electronics' for post-surgical care.
