A facile design of nucleocapsid-like Au@NiO@CuO nanocomposites with MWCNT for glucose sensing

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.

Electrochemical dual signal sensing platform for the simultaneous determination of dopamine, uric acid and glucose based on copper and cerium bimetallic carbon nanocomposites

A highly sensitive electrochemical sensor for the simultaneous dual signal determination of dopamine (DA), uric acid (UA) and glucose (Glu) has been obtained using nanocomposites based on the copper and cerium bimetallic nanoparticles and carbon nanomaterials of graphene and single-walled carbon nanotubes in the presence of Tween 20 (GR-SWCNT-Ce-Cu-Tween 20) modified glassy carbon electrode. The surface morphology of the nanocomposites was characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD), and the electrochemical behavior of the sensor was investigated by cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) with potassium ferricyanide as probe. In the coexistence system of DA, UA and Glu, three clear and well-isolated voltammetric peaks were obtained by CV and differential pulse voltammetry (DPV), and oxidation peak currents of DA and UA are positively correlated with their concentrations respectively, while the peak current of Glu is negatively correlated with its concentration. Linearity was obtained in the ranges of 0.1-100 µM for dopamine, 0.08-100 µM for uric acid and 1-1000 µM for glucose with DPV, and the detection limits (S/N = 3) of 0.0072 µM, 0.0063 µM, and 0.095 µM for DA, UA and Glu, respectively. The method was successfully applied to the determination of DA, UA and Glu in blood serum samples, which provided a reference for further sensor research.

A point-of-care diagnostics logic detector based on glucose oxidase immobilized lanthanide functionalized metal-organic frameworks

In this work, a novel lanthanide functionalized metal organic framework enzyme (L-MOF-enzyme) composite has been first prepared via a surface attachment strategy between Eu³⁺@UMOF and glucose oxidase (GOx). Here, the Eu³⁺@UMOF can be used as a support for GOx immobilization and also a responsive fluorescent center towards glucose (Glu). The resulting material not only exhibits fascinating luminescence properties based on the ⁵D₀→⁷F₂ transition of Eu³⁺ and the catalytic performance of enzymes, but also some advantages of MOF-enzyme composites, including better stability, and great fluorescence selectivity and sensitivity towards Glu (detection limit = 0.2 μM). Besides, the composite exhibited an excellent selectivity and sensitivity towards Glu in serum and urine under room temperature and neutral conditions, which breaks the limitation of specific catalytic conditions of enzymes. Taking all the advantages of the L-MOF-enzyme composite, a point-of care (POC) diagnostics logic detector which can be used for the fluorescence detection of Glu in urine is designed. From the three outputs of the logic detector (L, M and H), we can intuitively realize the self-diagnosis of the three ranges of Glu concentrations that act as the inputs of the detector (0.1 μM-10 μM, 10 μM-10 mM, >10 mM) by the naked eye. The logic detector allows us, especially diabetics, to instantly detect glucose levels in the urine without going to the hospital for complicated inspections. This is the first attempt using L-MOFs combined with GOx to construct a POC diagnostics logic detector for fluorescence detection of Glu.