Universal Sustainable Adhesive Bioelectronics Enabled by Hierarchical Architectures

Recent studies on soft adhesives have sought to deeply understand how their chemical or mechanical structures interact strongly with living tissues. The aim is to optimally address the unmet needs of patients with acute or chronic diseases. Synergistic adhesion involving both mechanical interactions (capillarity-assisted suction stress) and electrostatic (hydrogen bonds) seems to be effective in overcoming the challenges associated with long-term unstable coupling to tissues. Here, we developed the electrostatically and mechanically synergistic mechanism of sustainable tissue adhesion with minimal residue by implementing hybrid multiscale architectures.[1] By investigating various geometric parameters of microchannels on the adhesive surface, we develop a simple model to maximize adhesion strength via a time-dependent zig-zag profile and an arresting effect against crack propagation.[2] In addition, a thermodynamic model based on a tailored multiscale combinatory adhesive was proposed. The model supported the experimental results that the thermodynamically controlled swelling of the porous hydrogel embedded in the hierarchical elastomeric structure enhances biofluid-insensitive sustainable in situ adhesion to diverse soft, slippery, and wet organ surfaces, as well as clean detachment in the peeling direction. Based on the robust tissue adhesion capability, we successfully demonstrated universal reliable measurements of electrophysiological signals generated by various tissues ranging from rodent sciatic nerve, the muscle, brain, and human skin.<br/><br/>[1] Da Wan Kim et. al. Adv. Mater. 2022, 34(5), 2105338.<br/>[2] Da Wan Kim et. al. Adv. Funct. Mater. 2019, 29, 1807614.