Archetypal sandwich-structured CuO for high performance non-enzymatic sensing of glucose

Abstract

In the quest to enhance the selectivity and sensitivity of novel structured metal oxides for electrochemical non-enzymatic sensing of glucose, we report here a green synthesis of unique sandwich-structured CuO on a large scale under microwave mediated homogeneous precipitation conditions. The physicochemical studies carried out by XRD and BET methods show that the monoclinic CuO formed via thermal decomposition of Cu(2)(OH)(2)CO(3) possesses monomodal channel-type pores with largely improved surface area (~43 m(2) g(-1)) and pore volume (0.163 cm(3) g(-1)). The fascinating surface morphology and pore structure of CuO is formulated due to homogeneous crystallization and microwave induced self assembly during synthesis. The cyclic voltammetry and chronoamperometry studies show diffusion controlled glucose oxidation at ~0.6 V (vs. Ag/AgCl) with extremely high sensitivity of 5342.8 μA mM(-1) cm(-2) and respective detection limit and response time of ~1 μM and ~0.7 s, under a wide dynamic concentration range of glucose. The chronoamperometry measurements demonstrate that the sensitivity of CuO to glucose is unaffected by the absence of dissolved oxygen and presence of poisoning chloride ions in the reaction medium, which essentially implies high poison resistance activity of the sandwich-structured CuO. The sandwich-structured CuO also shows insignificant interference/significant selectivity to glucose, even in the presence of high concentrations of other sugars as well as reducing species. In addition, the sandwich-structured CuO shows excellent reproducibility (relative standard deviation of ~2.4% over ten identically fabricated electrodes) and outstanding long term stability (only ~1.3% loss in sensitivity over a period of one month) during non-enzymatic electrochemical sensing of glucose. The unique microstructure and suitable channel-type pore architecture provide structural stability and maximum accessible electroactive surface for unimpeded mobility of glucose as well as the product molecules, which result in the excellent sensitivity and selectivity of sandwich-structured CuO for glucose under non-enzymatic milieu.

Carnation‐like CuO Hierarchical Nanostructures Assembled by Porous Nanosheets for Nonenzymatic Glucose Sensing

“…As shown in Figure 6 (a), the CuO hierarchical nanostructures-based sensor is almost insensitive to common organics such as dopamine, uric acid, ascorbic acid, sucrose, maltose, and lactose. In contrast, some of the previously reported CuO-based sensors such as flower-like CuO hierarchical films on copper foils [28], archetypal sandwich-structured CuO [29], CuO nanoplates on Cu foils [32], and flexible 3D porous CuO nanowire arrays on Cu foils [37] could not well resist interference from the aforementioned organics, although they exhibited moderate sensitivity to glucose electro-oxidation. The good anti-interference performance of our CuO-based sensor might be attributed to the relatively low working potential of 0.4 V. In addition, the prepared CuO-based sensor also shows good anti-interference capacity to some inorganic salts such as NaCl, Na 2 SO 4 , KNO 3 , NaHCO 3 , and sodium citrate as shown in Figure 7 (b).…”

“…As can be seen, the CuO electrode almost exhibits no catalytic activity toward electro-oxidation of glucose when the applied potential is below 0.1 V. The anodic current at the CuO electrode increases with the increase of the applied potential in the range of 0.20 .4 V, and decreases with further increase of the applied potential because that high potential could promote fast oxidation of glucose, which would lead to accumulation of intermediates and reaction products on the electrode surface and block of the catalytic active sites, and thus further oxidation of glucose being hindered [15]. This fact indicates the CuO electrode exhibits the highest electrocatalytic activity toward glucose oxidation at an applied potential of 0.4 V, which is lower than the detection potentials needed by most of other CuO-based enzymeless glucose sensors [22,24,28,29,33].…”

“…On the other hand, the introduced components in the CuO-based nanocomposites will inevitably cause production cost increasing. In addition, many micro-/ nanostructured CuO-based nonenzymatic sensors work only at a high applied potential (near to or higher than 0.6 V) [22,24,28,29], which can induce amperometric interference from the oxidation of many endogenous reducing substances such as AA, UA and dopamine (DA) in the biological fluids. Even so, the sensitivity for most of the current CuO-based enzymeless sensors is only of a magnitude of mA mM À1 cm…”

Synthesis of Novel CuO Nanosheets with Porous Structure and Their Non‐Enzymatic Glucose Sensing Applications

“…It can be seen that the sensitivity of the as-prepared sensor are comparable or even better than most reported glucose sensors. In addition, the optimal applied potential of 0.35 V was more negative than those of 0.48 [38], 0.50 [35,39,45], and 0.60 [32,34,[42][43][44] in former reports of CuO film electrode. It was known that the interfering species (UA, AA) are easy to oxidation at more positive potential, resulting in severe interference to the oxidation of glucose.…”

Cu2+1O/graphene nanosheets supported on three dimensional copper foam for sensitive and efficient non-enzymatic detection of glucose

“…Without glucose in alkaline electrolyte, a reduction peak around 600 mV vs. SCE was found which corresponds to the Cu 2+ /Cu 3+ redox reaction. 29 Aer addition of 5 mM glucose, evident enhancement of anodic peak corresponding to the irreversible oxidation of glucose was observed. Although the underlying mechanism during glucose oxidation is currently unknown, it has been generally considered that the Cu 3+ species which might be an electron-transfer medium catalyzed glucose oxidation and produced gluconolactone and further hydrolyzed to glucose acid.…”