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

A 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 phase-pure cubic Cu₂S nanoparticles, uniformly distributed within the 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 an 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⁻¹) 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.