Tissue-Adhesive Carbon Nanotube Bioelectronics with Intrinsic Stretchability and Mechanical Adaptation.

Abstract

Interfaces for soft bioelectronics must retain conformal and low-noise contact with dynamic and hydrated tissues without causing mechanical mismatches. This study integrates a viscoelastic, self-healing polymer (SHP) with a surface-embedded carbon nanotube (CNT) network and a catechol-modified alginate (Alg-CA) overlayer to enable wet adhesion while preserving polymer-like mechanical properties. Tensile tests across representative strain rates (3.3 and 50% s^-1) indicate that CNT-SHP exhibits a stress-strain response similar to that of pristine SHP. Fracture-energy analysis and rapid stress relaxation show that CNT-SHP follows the energy dissipation characteristics of SHP. The Alg-CA layer improves electrochemical coupling by reducing impedance and increasing charge delivery <i>in vitro</i>, maintaining stability during saline immersion, and supporting wet adhesion on porcine tissues under cyclic loading. Cytotoxicity assays and short-term histology indicate reduced adverse tissue response relative to CNT-SHP without Alg-CA. <i>In vivo</i>, CNT-SHP enables motion-tolerant epicardial electrocardiogram in anesthetized and freely moving rats, maintains multiweek signal quality, supports reliable low-threshold ventricular pacing, and achieves effective sciatic-nerve stimulation. These results demonstrate the potential for stable sensing and stimulation in dynamic and wet tissues.