Designing copper sulfide nanocrystal-based non-enzymatic glucose sensor: An electrochemical and field-effect transistor-based sensing strategy

Abstract

Polyaniline stabilized copper (I) sulfide (Cu2S) nanocrystal was synthesized using a two-step method and employed as a catalyst for glucose sensing in electrochemical and field-effect transistor-based platforms. Comprehensive structural and spectroscopic analysis confirmed the formation of a phase-pure cubic Cu2S nanoparticles, uniformly distributed within polyaniline matrix. The Cu2S-modified electrode demonstrated effective redox-mediated glucose oxidation in alkaline media, as validated through cyclic voltammetry, differential pulse voltammetry and chronoamperometry techniques. In a field-effect transistor configuration, based on extended-gate approach, the Cu2S-modified device exhibited a sensitivity of 0.053 mA.mM-1.cm-2, with a detection limit of 0.16 mM and linearity across the glucose concentration range of 2-18 mM. The sensor displayed high selectivity against common interfering species, exhibited a minimal drift current (0.04 mA/h) for 12 hours of continuous operation and demonstrated moderately good shelf-life stability during 8 weeks of storage under ambient conditions. The practical applicability of the Cu2S-modified transistor-based sensor was further demonstrated through real-sample analysis, which exhibited high accuracy and excellent repeatability, highlighting its potential for use in biomedical and clinical applications.