Deformable and Stretchable EGaIn/Graphene-Based Electrochemical Biosensors

EGaIn has attactive properties for soft eletronics, such as wearable and implantable electronic devices for healthcare applications, due to its high conductivity and deformability near room temperature. However, the formation of an insulating native oxide film of EGaIn impedes its application to soft and stretchable electrochemical biosensors. Herein, we introduce reduced graphene oxide to EGaIn to achieve electrochemical stability and excellent conductivity as well as deformable properties. Graphene oxide easily undergoes galvanic replacement reaction on the surface of EGaIn particles forming reduced graphene oxide capped EGaIn core-shell particles (LM-RGO CSPs), which can be further fabricated to patternable stretchable electrochemical biosensing devices. The resulting deformable electrodes show excellent electrochemical conductivity and stability by preventing the native oxide film growth of EGaIn, even under repetitive stretching with 30% strain without any delamination of RGO. Also, the outer layer of RGO can be further decorated with metals which can effectively catalyze enzymatic reactions for glucose biosensing. In this talk, we will discuss the deformable mechanisms of LM-RGO CSPs-based electrochemical biosensors revealing specific interfacial attractions between RGO and LM, and excellent electrochemical biocatalytic activity for sensitive glucose detection under strains, based on sub-micro sized particle characteristics and their facilitated electron transfer between electrodes and glucose oxidase enzyme. We envision such an electrochemical device system can serve as a platform for multi-modal deformable wearable biosensing devices for healthcare applications, overcoming the inherent limitations of EGaIn as a soft conductor and taking advantage of the excellent conductivity of graphene.