Permeable and Durable Liquid-Metal Fiber Mat as Implantable Physiological Electrodes with Long-Term Biocompatibility

Implantable physiological electrodes provide unprecedented opportunities for real-time and uninterrupted monitoring of biological signals. Most implantable electronics adopt thin-film substrates with low permeability that severely hampers tissue metabolism, impeding their long-term biocompatibility. Recent innovations have seen the advent of permeable electronics through the strategic modification of liquid metals (LMs) onto porous substrates. However, the durability of these electronics is limited by the inherent poor wettability of LMs, particularly within the intricate 3D skeleton of the porous substrate. Herein, the study reports a spatial wettability tuning strategy that solves the wettability issue of LMs within the porous substrates, enabling the LM physiological electrodes with high durability and long-term biocompatibility. The study demonstrates the use of the electrodes as implantable neural interface to realize in vivo acquisition of electrocardiograph and electrocorticogram signals with long-term biocompatibility and high signal-to-noise ratio. This work demonstrates a promising direction for rational design of durable implantable bioelectronics with long-term biocompatibility.