Non-enzymatic Glucose Sensors Based On Self-supported Cu And CuNi Nanomaterial Electrode

Diabetes mellitus is a chronic metabolic disease, and it would cause a variety of complications which endanger human health. However, such complications can be significantly reduced by stringent personal control of blood glucose concentration.Therefore, it is crucial to develop a fast, accurate and stable technique for the detection of glucose. In the past decades, people has made great progress in the field of non-enzymatic electrochemical sensing of glucose, but mostly working electrodes for detecting of glucose were usually fabricated by sticking active materials on the surface of glassy carbon electrode. The aforementioned modified electrode performed many shortcomings, for example, the complicated preparation; active materials easy to fall off;poor reproducibility and stability. The self-supported electrode which prepared by directly electrodepositing metal or metal oxide on the substrate surface or manufacturing microstructure on the metal surface by chemical corrosion would overcome the inherent defects of chemically modified electrode, for instance, the active materials which deposited on substrate surface is not easy to fall off; the electrode performs excellent reproducibility and stability; the useful life of the electrode is longer.In this paper, we prepared two kinds of self-supported electrodes of titanium based Cu and CuNi alloy by the method of constant-potential electrodeposition, and the electrochemical glucose biosensor was constructed using the two electrodes. The following is the main research results of this paper:(1) Cu nanowires were constructed on Ti foils by the method of constant-potential electrodeposition, and the electrochemical performance for non-enzymatic glucose detection was studied. The results showed that the electrode exhibited a high sensitivity of 4984.6 μA·mM-1·cm-2(R2=0.9965) to glucose, a linear detection range from 1.0μmol·L-1 to 6.053 mmol·L-1, a detection limit of 0.33 μmol·L-1(S/N=3), a response time of < 4 s in 0.1 mol·L-1 NaOH electrolyte solution at 0.7 V. The current response of the three common interfering substances dopamine, ascorbic acid and uric acid caused negligible interference to the response of glucose on the Cu nanowire electrode, so the sensor was highly selective to glucose. In addition, the non-enzymatic glucose sensor has been successfully used for the assay of glucose in human serum samples with highaccuracy.(2) The dendritic CuNi alloy electrode on Ti foils was prepared by the method of constant-potential electrodeposition in the electrochemical workstation, which was more conducive to electron transfer due to its large surface area to volume ratio and continuous structure. The dendritic structure and the collaborative catalytic effect of bimetallic system make the self-supported CuNi alloy electrode highly active to glucose electrooxidation. The self-supported CuNi alloy electrode exhibited excellent glucose sensitivity, up to 6598.5 μA·mM-1·cm-2(R2=0.9965), wider linear range(5.0 μmol·L-1 ~2.2 mmol·L-1), lower detection limit(1.67 μmol·L-1, S/N=3), faster response time(< 4s), and more remarkable stability in 0.1 mol·L-1 NaOH electrolyte solution at 0.55 V. In addition, the glucose sensor is expected to apply in the actual detection of human serum samples.