An integrated nanoflower-like MoS2@CuCo2O4 heterostructure for boosting electrochemical glucose sensing in beverage

A novel hollow CuMn-PBA@NiCo-LDH nanobox for efficient detection of glucose in food

Designing a rapid and sensitive glucose detection method is of great significance to public health. Herein, hollow CuMn-PBA@NiCo-LDH nanoboxes (CuMn-PBA@NiCo-LDH NBs) were prepared using acid etching, cation exchange, and reflux method. The modified electrode exhibited outstanding electrocatalytic performance for glucose oxidation due to the unique hollow nanostructure and synergistic effects. The CuMn-PBA@NiCo-LDH NBs electrode displayed excellent electrocatalytic oxidation activity for glucose in an alkaline solution. Under optimal conditions, the electrode achieved a wide linear range (0.0005-1 mmol L-1, and 1-7 mmol L-1) and high sensitivity (10,300 μA L/mmol cm-2 and 5310 μA L/mmol cm-2), with a limit of detection (LOD) of 19 nmol L-1. The feasibility of the sensor applied to the detection of glucose was verified in real food samples through spiked recovery experiments. This electrode material offers an alternative method for the non-enzymatic glucose sensors.

In situ synthesis of self-supporting conductive CuCo-based bimetal organic framework for sensitive nonenzymatic glucose sensing in serum and beverage

Most MOFs are associated with the inherent defect of low conductivity, limiting their further application in electrochemical sensing. Herein, a self-supporting conductive CuCo-based bimetal organic framework with HHTP as the organic ligand was in situ synthesized on carbon cloth via a one-step hydrothermal method, namely CuCo-MOF/CC. Benefiting from the advantages of electrical conductivity and bimetallic synergies, CuCo-MOF/CC exhibited remarkable electrocatalytic performance toward glucose. Consequently, the prepared sensor demonstrated an outstanding sensitivity of 9317 μA mM-1 cm-2, a wide range of 0.25-2374.5 μM, a low determination limit (0.27 μM), and a rapid response time (1.6 s). The reproducibility, stability, and selectivity were also proved to be satisfactory. Furthermore, the remarkable feasibility of proposed sensor was confirmed in serum and beverages. With the convenience of the one-step hydrothermal method and portability of self-supporting electrode, CuCo-MOF/CC has emerged as a promising candidate for commercial glucose sensors.

Hierarchical N-doped porous carbon scaffold Cu/Co-oxide with enhanced electrochemical sensing properties for the detection of glucose in beverages and ascorbic acid in vitamin C tablets

This research focuses on the development of a highly efficient electrocatalyst, CuxO/NPC@Co3O4/NPC-10-7, for detecting glucose and ascorbic acid. In a 0.1 M NaOH solution, the modified electrode exhibits a sensitivity of 3314.29 μA mM-1 cm-2 for glucose detection. The linear range for ascorbic acid sensing is 0.5 μM - 23.332 mM, with a detection limit as low as 0.24 μM. In a 0.1 M PBS solution, the linear range for ascorbic acid detection extends to 43.328 mM, which represents the best performance reported to date by chronoamperometry. Moreover, the electrode demonstrates high accuracy, with a recovery rate of 96.80 % - 103.60 % for glucose detection and a recovery rate of 95.25 % - 104.83 % for ascorbic acid detection. These results suggest that the CuxO/NPC@Co3O4/NPC-10-7 modified electrode shows significant potential for practical applications in food detection.

Integrated Cu-Au stereo microelectrode arrays and microfluidic channels for the electrochemical detection of glucose

Noble and transition metal nanomaterials are widely used in glucose sensing. However, the fabrication of these sensors still suffers from complex nanomaterial synthesis process and unstable nanomaterial loading on sensing surfaces. Herein, a Cu-Au bimetallic microelectrode array was prepared via local electrochemical deposition and electrochemical reduction without the need for templates and additional nanomaterial preparation processes. Based on the COMSOL computational fluid study, the obtained microelectrode arrays combined with microfluidic channels allow the continuous and rapid detection of glucose. Large number of active sites on the surface of 3D nano-arrays contributes to excellent sensing performance for glucose, with good linear detection ranges in 10 µM to 4 × 102 µM and 4 × 102 µM to 4 × 105 µM, and a low detection limit of 284 nM. The feasibility of sensor in real sample was verified by detecting glucose in beverages with good recoveries ranging from 95.50% to 104.31%.

Synthesis of unique three-dimensional CoMn2O4@Ni(OH)2 nanocages via Kirkendall effect for non-enzymatic glucose sensing

Transition metal oxides / hydroxides, which have the advantages of wide distribution, low price, low toxicity, and stable chemical properties, have attracted much attention from researchers. Therefore, this work reports the construction of the unique CoMn2O4 nanocages assisted by the Kirkendall effect, and worm-like Ni(OH)2 nanoparticles were grown on the surface via hydrothermal method, the final product CoMn2O4@Ni(OH)2 nanocages were applied to construct efficient and sensitive non-enzymatic glucose electrochemical sensing. The stable three-dimensional hollow CoMn2O4 nanocages structure, not only can provide a wider specific surface area and more abundant active sites, its porous structure also can effectively inhibit the aggregation of nanoparticles, increase the ion diffusion path, shorten the electron transport distance, and improve the electrical conductivity. Loading Ni(OH)2 nanoparticles on the CoMn2O4 nanocages can increase catalytic sites, and further strengthen the electrocatalytic performance. Due to the good synergistic effect between CoMn2O4 and Ni(OH)2, CoMn2O4@Ni(OH)2 nanocages electrochemical sensor can achieve sensitive and rapid detection of trace glucose, with excellent linear range (8.5-1830.5 μM), low limit of detection (0.264 μM), high sensitivity of 0.00646 μA mM-1 cm-2, and outstanding repeatability. More importantly, the sensor has been successfully applied to the determination of blood glucose in human serum with good recoveries (95.64-104.3 %). This work provides a novel scheme for blood glucose detection and expands the application of transition metal oxides / hydroxides in the field of electrochemical sensing.

Three-Dimensional Electrochemical Sensors for Food Safety Applications

Considering the increasing concern for food safety, electrochemical methods for detecting specific ingredients in the food are currently the most efficient method due to their low cost, fast response signal, high sensitivity, and ease of use. The detection efficiency of electrochemical sensors is determined by the electrode materials' electrochemical characteristics. Among them, three-dimensional (3D) electrodes have unique advantages in electronic transfer, adsorption capacity and exposure of active sites for energy storage, novel materials, and electrochemical sensing. Therefore, this review begins by outlining the benefits and drawbacks of 3D electrodes compared to other materials before going into more detail about how 3D materials are synthesized. Next, different types of 3D electrodes are outlined together with common modification techniques for enhancing electrochemical performance. After this, a demonstration of 3D electrochemical sensors for food safety applications, such as detecting components, additives, emerging pollutants, and bacteria in food, was given. Finally, improvement measures and development directions of electrodes with 3D electrochemical sensors are discussed. We think that this review will help with the creation of new 3D electrodes and offer fresh perspectives on how to achieve extremely sensitive electrochemical detection in the area of food safety.

Synthesis of a Ni(OH)2@Cu2Se hetero-nanocage by ion exchange for advanced glucose sensing in serum and beverages

Cu₂Se nanosheets were coated on the surface of Ni(OH)₂ nanocages (NCs) by ion exchange driven by selenium incorporation. The resulting Ni(OH)₂@Cu₂Se hollow heterostructures (Ni(OH)₂@Cu₂Se HHSs) showed high electrical conductivity and electrocatalytic activities derived from the synergistic effects of Ni/Cu phases. These structures enhanced glucose adsorption abilities, confirmed by density function theory (DFT) calculations, and the robustness of the integrated nano-electrocatalyst. Remarkably, Ni(OH)₂@Cu₂Se HHSs modified electrodes excited excellent glucose sensing behavior with a wide linear range (0.001-7.5 mM), a sensitivity up to 2420.4 Μa mM^-1 cm², a low limit of detection (LOD, 0.15 μM), and fast response (less 2 s). Furthermore, Ni(OH)₂@Cu₂Se HHSs competently analyzed glucose in serum and beverages with good recoveries ranging from 94.4 to 103.6%. Integrating copper selenide and Ni-based materials as 3D hollow heterostructures expands the selection of electrocatalysts for sensitive glucose detection in food and biological samples.

Progress of Enzymatic and Non-Enzymatic Electrochemical Glucose Biosensor Based on Nanomaterial-Modified Electrode

This review covers the progress of nanomaterial-modified electrodes for enzymatic and non-enzymatic glucose biosensors. Fundamental insights into glucose biosensor components and the crucial factors controlling the electrochemical performance of glucose biosensors are discussed in detail. The metal, metal oxide, and hybrid/composite nanomaterial fabrication strategies for the modification of electrodes, mechanism of detection, and significance of the nanomaterials toward the electrochemical performance of enzymatic and non-enzymatic glucose biosensors are compared and comprehensively reviewed. This review aims to provide readers with an overview and underlying concept of producing a reliable, stable, cost-effective, and excellent electrochemical performance of a glucose biosensor.