Chemically anchored metal–hydrogel bilayers for ultrasoft and metallic biointerfaces

Metals are essential components of bioelectronic systems, such as contact electrodes, interconnects, and sensors. However, their inherent rigidity poses major challenges for integration in soft bioelectronics. In particular, the mechanical mismatch between metals and biological tissues can cause reduced signal fidelity and unwanted tissue damage. To address these issues, various geometrical engineering approaches have been explored to increase the deformability of metals. For example, strain-relief layers have been investigated; however, physically laminated structures often fail to adequately dissipate strain under deformation. Here, we present a chemically conjugated, monolithic metal-hydrogel bilayer, imparting high deformability to metals with minimal compromise in electrical conductivity. The formation of chemically anchored ligand interactions between the metal and hydrogel induces…