Metal Wire Networks Functionalized with Nickel Alkanethiolate for Transparent and Enzymeless Glucose Sensors

Abstract

Futuristic healthcare technology including glucose sensors demands wearable components that ought to be transparent and flexible. Nickel nanostructures have proven to be highly efficient as electrocatalysts for glucose sensors. In this study, we explore single-source precursors of nickel alkylthiolate, Ni(SR)2, complexes as active electrode materials and coat them on a transparent gold (Au) mesh network to fabricate a transparent and highly efficient glucose sensor. The metal thiolate complex is electrooxidized in the alkaline medium by repeated cyclic voltammetry measurements to give rise to Ni redox-active centers with sharp anodic and cathodic peaks. Among different chain length metal alkylthiolates, nickel butanethiolate with the shortest carbon chain (C4) is found to be the most efficient in retaining sharp oxidation at low potential value and high current density. The electrochemical property of nickel butanethiolate toward glucose oxidation is examined on different electrode surfaces such as Au thin film, Au mesh, and fluorine-doped tin oxide (FTO). Interestingly, glucose oxidation takes place most efficiently on a Au mesh network compared to Au film and FTO substrates. The Ni(SC4H9)2/Au mesh exhibited two linear ranges of detection from 0.5–2 and 2–11 mM with a sensitivity value of 675.97 μA mM–1 cm–2 and a limit of detection of 2.2 μM along with excellent selectivity and reproducibility. The present study demonstrates that nickel butanethiolate on a Au mesh acts as a promising functional and transparent electrode material with the possibility of large-scale production for practical glucose detection.