CuO nanorods supported Pd nanoparticles as high performance electrocatalysts for glucose detection

Advances of Transition Metal-Based Electrochemical Non-enzymatic Glucose Sensors for Glucose Analysis: A Review

Glucose concentration is a crucial parameter for assessing human health. Over recent years, non-enzymatic electrochemical glucose sensors have drawn considerable attention due to their substantial progress. This review explores the common mechanism behind the transition metal-based electrocatalytic oxidation of glucose molecules through classical electrocatalytic frameworks like the Pletcher model and the Hydrous Oxide-Adatom Mediator model (IHOAM), as well as the redox reactions at the transition metal centers. It further compiles the electrochemical characterization techniques, associated formulas, and their ensuing conclusions pertinent to transition metal-based non-enzymatic electrochemical glucose sensors. Subsequently, the review covers the latest advancements in the field of transition metal-based active materials and support materials used in non-enzymatic electrochemical glucose sensors in the last decade (2014-2023). Additionally, it presents a comprehensive classification of representative studies according to the active metal catalysts components involved.

Advancing Diabetes Management: The Future of Enzyme-Less Nanoparticle-Based Glucose Sensors-A Review

BACKGROUND

Glucose is vital for biological processes, requiring blood sugar levels to be maintained between 3.88 and 6.1 mmol/L, especially during fasting. Elevated levels signal diabetes, a global concern affecting 537 million people, necessitating effective glucose-monitoring devices.

METHOD

Enzyme-based sensors, though selective, are sensitive to environmental factors. Nonenzymatic sensors, especially those with nanoparticles, offer stability, high surface area, and cost-effectiveness. Existing literature supports their immediate glucose oxidation, showcasing exceptional sensitivity.

RESULTS

This review details nonenzymatic sensors, highlighting materials, detection limits, and the promise of nanoparticle-based designs, which exhibit enhanced sensitivity and selectivity in glucose detection.

CONCLUSION

Nanoparticle-based sensors, as reviewed, show potential for glucose monitoring, overcoming enzyme-based limitations. The conclusion suggests future directions for advancing these sensors, emphasizing ongoing innovation in this critical research area.

Construction of a Hierarchical Structure of Bimetallic Oxide Derived from Metal-Organic Frameworks

Bimetallic oxides are a class of promising advanced functional metal nanomaterials, especially in terms of the sophisticated hierarchical structure of bimetallic oxide, which not only is in favor of enhancing their intrinsic physiochemical properties because of more accessible actives sites but also is capable of integrating the synergistic effect between two metals. Herein, we report a novel strategy to controllably construct bimetallic CuO/ZnO nanomaterials with sophisticated hierarchical structure through a pseudomorphic transformation and subsequent calcination process. The resulting unique hierarchical structure of ZnO/CuO is primarily constituted of a nanosphere and a rod grafted in a microscale cube with multidimensional size, which thus results in excellent dispersion, superior charge-transport capability, and abundant accessible active sites. Impressively, the optimized hierarchical structure product of CuO/ZnO (4:1) demonstrates an excellent glucose detection performance with a rapid response time, a wide linear range, a low detection limit, and strong antiinterference ability, realizing more advantages than commercial CuO or ZnO materials and shedding light on the positive correlation of the structure and performance. This study provides a new strategy for the controllable fabrication of the sophisticated hierarchical structure of bimetallic oxide nanomaterials.

Non-Enzymatic Glucose Sensors Involving Copper: An Electrochemical Perspective

Non-enzymatic glucose sensors based on the use of copper and its oxides have emerged as promising candidates to replace enzymatic glucose sensors owing to their stability, ease of fabrication, and superior sensitivity. This review explains the theories of the mechanism of glucose oxidation on copper transition metal electrodes. It also presents an overview on the development of among the best non-enzymatic copper-based glucose sensors in the past 10 years. A brief description of methods, interesting findings, and important performance parameters are provided to inspire the reader and researcher to create new improvements in sensor design. Finally, several important considerations that pertain to the nano-structuring of the electrode surface is provided.

A non-enzymatic disposable electrochemical sensor based on surface-modified screen-printed electrode CuO-IL/rGO nanocomposite for a single-step determination of glucose in human urine and electrolyte drinks

A non-enzymatic disposable electrochemical sensor coupled with an automated sample pretreatment paper-based device was developed to avoid an additional sample preparation step for glucose determination in human urine and electrolyte drinks. The automated sample pretreatment paper-based device was successfully fabricated by the simple coating of a strong alkaline solution on a patterned wax paper, and then attached on an electrochemical sensor. The nanocomposite of copper oxide nanoparticles, ionic liquid and reduced graphene oxide (CuO-IL/rGO) modified on the screen-printed carbon electrode (SPCE) was created and used as a non-enzymatic electrochemical glucose sensor. The presence of the CuO-IL/rGO nanocomposite on the screen-printed electrode surface was confirmed by transmission electron microscopy (TEM), scanning electron microscopy (SEM) with energy dispersive X-ray spectroscopy (EDX), and X-ray diffraction spectroscopy (XRD). Under optimal conditions, glucose was measured by dropping 100 μL sample solution on the device and detected via chronoamperometry (CA) using a smartphone potentiostat controlled by Android app., providing a rapid current response within 20 s and linearity in a range of 0.03-7.0 mM with a limit of detection (LOD) of 0.14 μM. Furthermore, this developed device was successfully applied for determining glucose levels in human urine and electrolyte drinks, exporting satisfying results correlated with a commercial enzymatic glucose biosensor and labeled values of the commercial products. Therefore, this device could be an alternative device for a non-enzymatic glucose sensor with single-step sample loading, allowing for real-time analysis, low cost, portability, disposability, and on-field measurement.

Enzyme Immobilization on Gold Nanoparticles for Electrochemical Glucose Biosensors

More than 50 years have passed since Clark and Lyon developed the concept of glucose biosensors. Extensive research about biosensors has been carried out up to this day, and an exponential trend in this topic can be observed. The scope of this review is to present various enzyme immobilization methods on gold nanoparticles used for glucose sensing over the past five years. This work covers covalent bonding, adsorption, cross-linking, entrapment, and self-assembled monolayer methods. The experimental approach of each modification as well as further results are described. Designated values of sensitivity, the limit of detection, and linear range are used for the comparison of immobilization techniques.

Co(OH)2 nanosheets decorated Cu(OH)2 nanorods for highly sensitive nonenzymatic detection of glucose

Co(OH)₂ nanosheets/Cu(OH)₂ nanorods composite electrodes for non-enzymatic glucose detection were fabricated by electrodepositing Co(OH)₂ nanosheets on Cu(OH)₂ nanorods substrate grown directly on the copper sheet via a simple one-step reaction. The Co(OH)₂ nanosheets/Cu(OH)₂ nanorods composite electrode was characterized by scanning electron microscopy, energy dispersive x-ray spectroscopy, x-ray diffraction and x-ray photoelectron spectroscopy. The glucose sensing performance of the composite electrode was investigated by cyclic voltammetry and chronoamperometry. The composite electrode shows high sensitivity of 2366 µA mM^-1 cm^-2 up to 2 mM with a lower detection limit of 0.17 mM (S/N = 3). The composite electrode is highly selective to glucose in the presence of various substances that always co-exist with glucose in real blood samples. The response of the composite towards human blood serum was in good agreement with that of commercially available glucose sensors, suggesting that a promising electrode material for highly sensitive and selective non enzymatic detection of glucose can be envisioned.

Sea urchin-like CuO particles prepared using Cu3(PO4)2 flowers as precursor for high-performance ethanol sensing

Cu₃(PO₄)₂ flowers are reported for the first time as a solid precursor for the preparation of hierarchical CuO particles with sea urchin-like morphology in the absence of self-assembled templates or matrixes. In the alkaline condition, Cu₃(PO₄)₂ transforms into Cu(OH)₂ firstly, and then into CuO through dehydration at room temperature. Different from soluble Cu salt as precursor, the basic building blocks for CuO are continuously supplied in a controlled manner form Cu₃(PO₄)₂ precursor, which ensures a nearly sustained supersaturated concentration that favors heterogeneous nucleation and progressive growth of sea urchin-like CuO particles. The gas sensing property of as-prepared sea urchin-like CuO particles to ethanol is investigated. The sea urchin-like CuO particles exhibit a good sensing performance in terms of high response, short response/recovery time, good selectivity, good reproducibility, and long-term stability. The facile strategy demonstrated here opens up a new strategy to fabricate hierarchical CuO particles with enormous potential from the perspective of practical application.

Electrochemical non-enzymatic glucose sensors: recent progress and perspectives

This review summarizes recent advances in the development of electrocatalysts for non-enzymatic glucose detection. The sensing mechanism and influencing factors are discussed, and the perspectives and challenges are also addressed.

Borax promotes the facile formation of hollow structure in Cu single crystalline nanoparticles for multifunctional electrocatalysis

Hollow Cu₂O and Cu are efficiently prepared using borax as structure-directing agent for electrocatalysis of glucose oxidation and H₂O₂ reduction.