Study on porous Cu-based enzyme-free glucose electrochemical sensor with different entrapping agents

A report is presented on a novel non-enzymatic amperometric glucose sensor based on three-dimensional porous Cu, which was directly reduced by hydrogen from Cu(OH)₂. The surface morphology of the synthesised nanoporous Cu was characterised using field-emission scanning electron microscopy and X-ray powder diffraction. Compared with the commercial Cu nanoparticles, the nanoporous Cu modified electrode shows better catalysis to glucose, which is attributed to the special porous Cu structure providing a favourable microenvironment for glucose adsorbed in large quantity. The interesting comparative study of different cross-linking agents for the immobilisation of nanoporous Cu reports that nafion, chitosan and multi-walled carbon nanotubes (MWCNTs) can all improve the catalysis effect of porous Cu on the glucose but the MWCNT shows the best sensitive response and stability. The MWCNT plays an especially important role in stability improvement by 20% of the efficiency. Under optimal conditions, a linear dependence of the catalytic current upon glucose concentration was obtained in the range of 5.0 × 10^-7-2.0 × 10^-3 M with a detection limit of 1.0 × 10^-7 M, a high sensitivity of 20.11 μA μM^-1, good stability and no current response from interfering species at the approximate physiological concentration level.