Interaction of Glucose with CuO: Glucose sensing platform

Rising incidence of diabetes has led to a rapidly increasing disease burden in emerging economies. Detection of blood glucose using non-enzymatic sensors is desirable to achieve a low detection limit in diabetic patients, who typically have blood glucose levels in a reference range of 1.1 - 20.08 mM. Low cost, biocompatible and stable copper oxide films have been developed in this work. Synthesis of the copper oxide nanomaterial was carried out in a deep eutectic solvent (DES) of gallic acid: choline chloride: ethylene glycol, which acts as a stabilizing agent, ensuring stability (∼ several months for CuO). Synthesized particles were characterized using X-Ray Diffraction (XRD), transmission electron microscope (TEM), selected area electron diffraction, scanning electron microscope, energy dispersive X-ray analysis and photoluminescence (PL). TEM data revealed nanoparticle diameters in the range of 56–60 nm. Under 325 nm excitation, films based on these nanoparticles exhibit a strong PL emission at 341nm, a shoulder peak at 410 nm, and deep level defect at 561 nm in addition to 664 nm emissions. As a preliminary study prior to incorporation in a sensing device consisting of an integrated PL (UV) source-driven colorimetric display, glucose spiked solutions (∼ 0.001 M) were added to the CuO film and studied under PL excitation. The emission spectrum exhibited a time-dependent, broad strongly enhanced fluorescent feature in 414–540 nm range on interaction with glucose. This establishes the initial feasibility of a real-time, regenerative, low-cost glucose sensing platform.