Water‐Based Conductive Ink Formulations for Enzyme‐Based Wearable Biosensors
Angelo Tricase, Anna Imbriano, Marlene Valentino, Nicoletta Ditaranto, Eleonora Macchia, Cinzia Di Franco, Reshma Kidayaveettil, Dónal Leech, Matteo Piscitelli, Gaetano Scamarcio, Gaetano Perchiazzi, Luisa Torsi, Paolo Bollella
Abstract
Abstract Herein, this work reports the first example of second‐generation wearable biosensor arrays based on a printed electrode technology involving a water‐based graphite ink, for the simultaneous detection of l ‐lactate and d ‐glucose. The water‐based graphite ink is deposited onto a flexible polyethylene terephthalate sheet, namely stencil‐printed graphite (SPG) electrodes, and further modified with [Os(bpy) 2 (Cl)(PVI) 10 ] as an osmium redox polymer to shuttle the electrons from the redox center of lactate oxidase from Aerococcus viridans (LOx) and gluocose oxidase from Aspergillus niger (GOx). The proposed biosensor array exhibits a limit of detection as low as (9.0 ± 1.0) × 10 −6 m for LOx/SPG‐[Os(bpy) 2 (Cl)(PVI) 10 ] and (3.0 ± 0.5) × 10 −6 m for GOx/SPG‐[Os(bpy) 2 (Cl)(PVI) 10 ], a sensitivity as high as 1.32 μA m m −1 for LOx/SPG‐[Os(bpy) 2 (Cl)(PVI) 10 ] and 28.4 μA m m −1 for GOx/SPG‐[Os(bpy) 2 (Cl)(PVI) 10 ]. The technology is also selective when tested in buffer and artificial sweat and is endowed with an operational/storage stability of ≈80% of the initial signal retained after 20 days. Finally, the proposed array is integrated in a wristband and successfully tested for the continuous monitoring of l ‐lactate and d ‐glucose in a healthy volunteer during daily activity. This is foreseen as a real‐time wearable device for sport‐medicine and healthcare applications.