Highly conductive, biocompatible and stretchable sputtered Pt electrode via island-bridge effect

Abstract

The development of stretchable electrodes is crucial for advancing soft electronics, including bio-integrated health systems and wearable devices. In this work, we present a biocompatible and highly conductive stretchable hydrogel-based electrode, by combining a conductive polymer (PEDOT:PSS) and a thin platinum layer (≈150 nm) deposited via RF sputtering.The 2-hydroxyethyl acrylate (2-HEA) hydrogel provides a flexible matrix, ensuring strong adhesion with the metal layer and the conductive polymer. The resulting electrode achieves a surface resistivity of 0.8 Ω sq-1 (≈8×106 S m-1) and maintains conductivity even after 500 stretch-relax cycles at 70% strain. Unlike conventional electrodes, it exhibits minimal resistance variation under strain due to a combined "island-bridge" conduction mechanism. Furthermore, biocompatibility tests confirm the electrode's suitability for skin-contact applications. This novel approach provides a promising solution for nextgeneration wearable and implantable bioelectronics, offering an optimal balance between high conductivity, mechanical durability, stretchability and biocompatibility.