Three-Dimensional Electrodes of Liquid Metals for Long-Term, Wireless Cardiac Analysis and Modulation.

Cardiovascular disease is a major public health issue, and smart diagnostic approaches play an important role in the analysis of electrocardiograms. Here, we present three-dimensional, soft electrodes of liquid metals that can be conformably attached to the surfaces of the heart and skin for long-term cardiac analysis. The fine micropillar structures of biocompatible liquid metals enable precise targeting to small tissue areas, allowing for spatiotemporal mapping and modulation of cardiac electrical activity with high resolution. The low mechanical modulus of these liquid-metal electrodes not only helps avoid inflammatory responses triggered by modulus mismatch between the tissue and electrodes, but also minimizes pain when embedded in biological tissues such as the skin and heart. Furthermore, in vivo experiments with animal models and human trials demonstrate long-term and accurate monitoring of electrocardiograms over a period of 30 days.