A Liquid Metal Route for Designing Stretchability and Nanoporosity in Gold Thin Film Bioelectrodes

Abstract

Nanostructured gold thin films are widely used biosensing materials due to their inertness, high surface area, favorable electrochemical properties, antifouling abilities, and biocompatibility. However, the structural integrity of thin films is easily compromised when stretched. Here we present a liquid metal synthesis route that allows room temperature fabrication of nanoscale thickness, nanoporous gold (NPAu) electrodes on stretchable polydimethylsiloxane (PDMS). Carbon nanofibers (CNFs) are introduced to maintain electrical conductivity of NPAu by suppressing crack formation/propagation and establishing intercrack conductive pathways. The PDMS-supported, CNF-reinforced NPAu retains its electrical conductivity at strains up to 80% and a relative resistance change of 11% under 2000 cyclic loads at 20% strain, demonstrating exceptional stability. NPAu-CNF demonstrates an electroactive surface area 1.8 times that of commercial Au electrodes, along with superior antifouling performance. These findings establish a protocol for realizing stretchability in thin film bioelectrodes, meeting the demand for developing conformable yet highly integrated biosensors.