Taehwan Lim  Sohee Lee  Sang Young Yeo

Vol. 59,  No. 4, pp. 194-202, Aug.  2022
10.12772/TSE.2022.59.194

liquid metal flexible electrode Electrochemical property PEDOT dopamine sensor

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Gallium-based liquid metals have gained significant attention as promising material platforms for flexible bioelectronics owing to their fluidic behavior but still metallic. However, low electrochemical stability owing to oxidation may limit the use of bioelectronics that typically operate under physiological conditions. Here, we developed a liquid metal core/polymer shell fiber platform for flexibility. Then, nanostructured conductive poly(3,4-ethylenedioxythiophene) (PEDOT) was encapsulated on the liquid metal surface to prevent oxidation. Mechanical property measurement demonstrated that the platform displayed high flexibility and low Young’s modulus that could minimize the mechanical mismatch between the fiber platform and soft human tissues. PEDOT encapsulation on the liquid metal surface offered the fiber platform-based electrode considerably higher electrochemical properties, such as lower impedance and higher charge storage capacity. The improved electrochemical performance enables the liquid metal-based fiber electrode to be used for electrochemical dopamine (DA) monitoring. This study demonstrated that the PEDOT structured flexible electrode had a sensitivity of 0.218±0.022 μA/μM and a limit of detection of 150 nM. Finally, the electrode could effectively detect DA under a plethora of byproducts produced by human metabolism. All the results confirmed the flexibility and remarkable electrochemical properties of the prepared liquid metal-based electrode, opening numerous design opportunities for next-generation liquid metal-based bioelectronics.