Researchers have developed a nanogenerator that can harvest biomechanical energy from the motion of the heart and thereby power an implanted pacemaker. “Millions of patients have implanted pacemakers, which were first used in the 1950s,” explain Zhou Li and Zhong Lin Wang, senior authors on the paper published in Nature Communications. “Their batteries are still bulky and typically must be replaced every 5–12 years.” The investigators aim to design a pacemaker that can be implanted for the lifetime of a patient.

The researchers developed an implantable pacemaker comprising a power management unit, a pacemaker unit and a novel implantable triboelectric nanogenerator (iTENG), containing two triboelectric layers. The iTENG was placed between the heart and the pericardium of a pig; cardiac motion caused periodic contact and separation of the two triboelectric layers, generating electrical energy, which could be stored in the capacitor of the power management unit.

The researchers demonstrated that after continuously harvesting energy from cardiac motion for approximately 200 min, electrical pulses (0.5 ms, 130 bpm) could be generated by the pacemaker and transmitted to the myocardium for cardiac pacing. In a pig with sinus arrhythmia induced by sinus node hypothermia, the iTENG-based pacemaker successfully converted the sinus arrhythmia to a pacing rhythm. The pig remained in sinus rhythm when, after about 1 min of pacing, the power supply voltage dropped and the pacemaker stopped working.

The researchers describe this new pacemaker as being symbiotic, because it converts biomechanical energy from the beating heart to electricity for powering the pacing module. When sinus rhythm is restored by these pulses, the recovered heart provides more energy for the pacemaker. Of note, the flexible iTENG technology can also be used to power other implantable devices (such as neural and muscle stimulators) as well as wearable electronic medical devices.