Work

Bioelectric energy harvesting from myocardial tissue in vivo: A new method for biological energy collection

Year: 2025

Type: article

Abstract: BACKGROUND: Bioelectric energy resulting from ion-based charge transfer processes is ubiquitously present in biological systems. OBJECTIVE: This study performed bioelectric energy harvesting from myocardial tissue in vivo. The available energy was compared with pacing energy consumption to assess the feasibility of an energy budget for self-powered cardiac pacing. METHODS: We developed an electrophysiological measurement system with electrical loading and harvesting capabilities. Microneedle electrodes were used as the primary tissue interface. Intramyocardial extracellular source signals were recorded from left ventricular sites in porcine hearts via epicardial access. We studied electrogram characteristics, loading effects, source impedances, and available energy. The harvester was used to extract energy and to convert millivolt signals from tissue sources to voltage levels required by modern integrated electronic circuits. Pacing thresholds and energy were also assessed. RESULTS: Per microneedle and heartbeat, we found 25 nJ of intrinsic bioelectric energy within 20-30 mV intramyocardial extracellular source signals. This tissue source supported continuous and repetitive energy extraction. Within 14 heartbeats, a portion of the energy could be accumulated and converted into 1-V output signals. During such a charging cycle, 23 nJ of bioelectric energy (1.7 nJ per heartbeat) was transferred from a single microneedle onto an external capacitor. The minimal pacing energy demand was 40 nJ per effective pacing pulse. CONCLUSION: We demonstrated continuous bioelectric energy harvesting and voltage boost conversion from myocardial tissue in vivo. A combined set of microneedles can extract energy needed for effective pacing. Bioelectric energy harvesting allows the collection of usable energy from very small electrodes.

Source: Heart Rhythm

DOI: 10.1016/j.hrthm.2025.06.003