Development Of Non-enzymatic Glucose Sensor Research Articles

Fabrication of Novel CuO Films with Nanoparticles-Aggregated Sphere-Like Clusters on ITO and Their Nonenzymatic Glucose Sensing Applications

In this work, novel nanoparticles-aggregated CuO sphere-like clusters were successfully synthesized on indium tin oxide (ITO) glass through a facile two-step procedure consisting of the fabrication of Cu2O films directly grown on ITO surface by electrodeposition, and subsequent calcinations of Cu2O films leading to the formation of CuO films. The morphology and structure of as-synthesized samples were characterized by scanning electron microscopy (SEM) and X-ray diffraction (XRD). It was found that the size of nanoparticles constituting sphere-like clusters structure obtained at 200[Formula: see text]C is much smaller than that of obtained at other temperature, which can provide large surface area for catalytic reaction. The CuO/ITO electrode was applied to detect glucose by cyclic voltammetry (CV) and amperometric detection ([Formula: see text]). It was found that the obtained CuO films modified ITO electrode exhibited a much higher electrocatalytic activity for the oxidation of glucose in an alkaline medium through heat treatment of 200[Formula: see text]C. A favorable performance with a high sensitivity of 1841.5544[Formula: see text][Formula: see text]A mM[Formula: see text] cm[Formula: see text] to glucose ranging from 1.0[Formula: see text][Formula: see text][Formula: see text]10[Formula: see text][Formula: see text]M to 5.0[Formula: see text][Formula: see text][Formula: see text]10[Formula: see text][Formula: see text]M, a low operating potential of 0.35 Vversus Ag/AgCl and a fast amperometric response (within 3[Formula: see text]s) were achieved on such CuO/ITO electrode. It also showed outstanding long-term stability and good reproducibility. Notably, poisoning by chloride ions and interference from ascorbic acid, uric acid and acetaminophen were negligible. Therefore, the nanoparticles-aggregated CuO sphere-like clusters would be a promising candidate electrode material for the development of nonenzymatic glucose sensors.

Carbon Nanotubes Supported Ru-Au Nanoparticles with Core-Shell Structure for Glucose Detection with High Resistance against Chloride Poisoning

Bimetallic Au-Ru nanoparticles (NPs) with novel core-shell morphology were prepared through a single-step microemulsion synthesis for the decoration of COOH surface modified multi-walled carbon nanotubes (fMWCNTs). The presence of Ru leads to particles with smaller diameters, improved distribution and adhesion on fMWCNTs, affording very good accessibility to the catalytic sites. Thereby, Ru exists in a highly amorphous state in the shell and as a solid solution in the gold lattice of the core. The effect of Ru on the activity and effectiveness of the catalyst were studied in alkaline solutions. Au-RuNPs/fMWCNTs exhibits a high sensitivity of 28.7 μA mM−1 cm−2 toward glucose and provides a linear range for physiological concentrations (1 mM–10 mM). Contrary to Au the Au-RuNPs/fMWCNTs electrode is highly resistant against poisoning by chloride ions, and the interference from the oxidation of common interfering species is effectively suppressed. Additionally, the presence of other sugars affects only marginally the response toward glucose. The role of Ru and the special core-shell morphology are discussed. The Au-RuNPs/fMWCNTs electrode exhibits good selectivity, high sensitivity toward glucose oxidation and applicability for glucose detection in real human serum samples, thus is promising for the future development of non-enzymatic glucose sensors.

Electrochemical Non-Enzymatic Glucose Sensor based on Hexagonal Boron Nitride with Metal-Organic Framework Composite

In this study, an amperometric non-enzymatic glucose sensor was developed on the surface of a glassy carbon electrode by simply drop-casting the synthesized homogeneous suspension of hexagonal boron nitride (h-BN) nanosheets with a copper metal-organic framework (Cu-MOF) composite. Comprehensive analytical methods, including field-emission scanning electron microscopy (FE-SEM), Fourier-transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), cyclic voltammetry, electrochemical impedance spectroscopy, and amperometry, were used to investigate the surface and electrochemical characteristics of the h-BN-Cu-MOF composite. The FE-SEM, FT-IR, and XRD results showed that the h-BN-Cu-MOF composite was formed successfully and exhibited a good porous structure. The electrochemical results showed a sensor sensitivity of 18.1 μAμM-1cm-2 with a dynamic linearity range of 10-900 μM glucose and a detection limit of 5.5 μM glucose with a rapid turnaround time (less than 2 min). Additionally, the developed sensor exhibited satisfactory anti-interference ability against dopamine, ascorbic acid, uric acid, urea, and nitrate, and thus, can be applied to the design and development of non-enzymatic glucose sensors.

Simple Design Disposable Non-Enzymatic Glucose Sensor Based on Flexible Ni/PET Electrode

Since Clark and Lyons explained the basic concepts of glucose enzymatic electrodes, there have been significant efforts on development of reliable devices for diabetes control. This metabolic disorder rooted in insulin deficiency which results in blood glucose concentrations lower or higher than normal range of 4.4 to 6.6 mM. The primary approach to develop electrochemical glucose sensors is to exploit enzymes to oxidize glucose and monitor hydrogen peroxide production. The complications associated with enzyme immobilization and the necessity for maintaining certain operating and storage condition (controlling temperature, pH and humidity) along with the enzymes high cost lead to the development of non-enzymatic glucose sensors (NEG). In NEG sensors, glucose is oxidized directly on electrode surface. In this study, a simple design disposable NEG sensor with high sensitivity and acceptable interference rejection was developed based on NiP/PET electrode. An activation-free Ni electroless metallization was performed using (3-Aminopropyl)trimethoxysilane (APTMS) and (3-Mercaptopropyl)trimethoxysilane (MPTMS) self-assembled monolayers (SAM). The affinity of –HS functional groups on MPTMS-SAM to Ni resulted in a thin film with excellent adhesion. A PMMA mask was used during Ni electroless deposition to obtain a 3-electrode configuration pattern on plastic substrate. Pt electrodeposition was carried out on two of the three Ni electrodes to serve as reference and counter electrodes. Nafion solution was drop-casted on Ni working electrode to reject interference. Electrochemical measurements were carried out in 0.1M KOH solution. 0.5 V was selected as the sensor working potential base on cyclic voltammetry characterizations in presence of glucose. Chronoamperometric measurements presented a wide linear range with high sensitivity of 230 µA.mM-1.cm-2. Results of interference studies proved the accuracy of sensor response in presence of ascorbic acid, uric acid and lactate (less than 15% error which is considered as clinically accurate). The study suggests a low-cost and high performance nonenzymatic glucose sensor compatible with roll to roll manufacturing and mass production.

Synthesis of flower-like cuo hierarchical nanostructures as an electrochemical platform for glucose sensing

Flower-like CuO hierarchical nanostructures were synthesized on copper foil substrate through a simple wet chemical route in alkaline media at room temperature. SEM images collected at different reaction times revealed the transformation of initially formed Cu(OH)2 nanowires to flower-like CuO nanostructures. The hierarchical structure of the as-prepared CuO showed high electrocatalytic activity towards the oxidation of glucose making it a promising electrode material for the development of non-enzymatic glucose sensor. The amperometric sensor exhibited a wide linear response to glucose ranging from 4.5 × 10−5 to 1.3 × 10−3 mol L−1 (R2 = 0.99317) at fixed potential of 0.3 V. The detection limit was 6.9 × 10−6 mol L−1 (LOD = 3σ/s) with a sensitivity of 1.71 μA μmol−1 cm−2. Moreover, the developed sensor offers a fast amperometric response, good selectivity and stability.

Development of non-enzymatic glucose sensor based on efficient loading Ag nanoparticles on functionalized carbon nanotubes

A facile strategy has been developed to fabricate silver nanoparticles (Ag NPs) through an electrochemical method with the assistance of metformin functionalized MWCNT (Ag@MH/MWCNT nanocomposite). Investigations by field emission scanning electron microscopy (FESEM) confirmed that the prepared nanocomposite have a porous structure that is constructed by interconnecting functionalized MWCNT framework. Electrochemical studies show that the nanocomposite exhibits high stability and excellent activity for electrocatalytic oxidation of glucose in alkaline solutions, which allows the Ag@MH/MWCNT to be used in enzyme-free amperometric sensors for glucose determination. It was confirmed that the Ag@MH/MWCNT based glucose biosensor presents wide response window for glucose concentrations of 1.0nM–350μM, short amperometric response time (4s), low detection limit of 0.0003μM (S/N=3), high sensitivity as well as good selectivity.

In situ synthesis of graphene-encapsulated gold nanoparticle hybrid electrodes for non-enzymatic glucose sensing

A novel route for in-situ synthesis of high-quality gold nanoparticles-encapsulated few layered graphene (AuNP-FLG) nanohybrids has been established. The AuNP-FLG nanohybrids were successfully synthesized by chemical vapor deposition technique and used as an electrocatalyst for high sensitive non-enzymatic glucose sensors. The amperometric response of the AuNP-FLG based electrode achieved an excellent electrocatalytic activity towards glucose oxidation with a wide linear detection range of 6 μM–28.5 mM, low detection limit of 1 μM and a sensitivity of 0.195 μA mM−1 cm−2 at operating potential of 0.0 V. Furthermore, the electrode also showed long-term stability (retention of 95.4% after two week) with negligible interference from ascorbic acid, 4-acetamidophenol and uric acid. The results implied that AuNP-FLG could be a promising electrode material in the development of non-enzymatic glucose sensors.

Development of non-enzymatic glucose sensor using recycled cobalt from cell phone Li-ion batteries

This article aims to present an alternative to recycling of spent Li-ion batteries applied to electrochemical sensor manufacturing. The cobalt, from cathode of Li-ion batteries, was recovered by electrodeposition onto AISI 430 stainless steel substrate and applied as glucose sensor. The composition of cathode utilized was obtained by AAS measures and corresponds to LiNi0,40Co0,60O2. Despite this composition, in the cobalt electrodeposition onto AISI 430 stainless steel the Ni is less of 1.7% (w/w) due the anomalous electrodeposition. The sensitivity of cobalt electrode for glucose detection is 70.2μA/mmolcm2 and the linear range is 1–10mmol/L. This result shows that the Co electrodeposited onto AISI 430 stainless steel is a promissory and low-cost non-enzymatic glucose sensor.

Size-controlled synthesis of Cu2O nanoparticles on reduced graphene oxide sheets and their application as non-enzymatic glucose sensor materials

Cuprous oxide nanoparticles uniformly dispersed on reduced graphene oxide (RGO) sheets were prepared by a polyol process using copper acetate and graphite oxide as precursors in diethylene glycol solution. The size of Cu2O particles can be controlled by changing the heat treatment time. With prolonging the heat treatment time at 140 °C from 0 to 30 min, the size of Cu2O particles on the reduced graphene oxide sheets decreases from 500 to 4 nm. The electrochemical activity of the Cu2O/RGO composites in potassium ferricyanide solution shows strongly sensitive on the size of Cu2O nanoparticles. Moreover, the smallest size of composite-based electrode shows excellent electrochemical activities for electrocatalytic oxidation of glucose in alkaline medium. The proposed biosensor can be applied to the quantification of glucose with a high sensitivity and durability, wide linear range, a low detection limit of 0.1 μM, and ease of construction, thus is promising for the future development of non-enzymatic glucose sensors.

Synthesis of Pt Decorated Copper Oxide Nanoleaves and Its Electrochemical Detection of Glucose

A novel platinum decorated CuO nanoleaves were synthesized through a facile co-precipitation method and further utilized as a sensing platform for glucose based on immobilization of Pt-CuO hybrid nanostructures with Nafion matrix. The prepared composites were characterized by X-ray Diffraction (XRD), field emission scanning electron microscopy (FE-SEM) and transmission electron microscopy (TEM). The modified electrode exhibits excellent electrocatalytic activity towards glucose as probed by cyclic voltammetry (CV) and chronoamperometry (CA) techniques. Comparing with pure CuO/Nf/GCE, Pt-CuO/Nf/GCE, as non-enzymatic electrode materials, exhibited a good response towards glucose with linear range 2–1000 μM with a higher sensitivity of 1681.7 μA mM−1cm−2 and detection limit of 11 μM. The excellent electrocatalytic performances could be attributed to the Cu(II)/Cu(III) multiple oxidation states system could promote the redox reactions between electrode materials and glucose, and the electroactive sites became more active due to the synergic effect. The results, high sensitivity, excellent selectivity and long term stability showing that, Pt-CuO is a promising material for the future development of nonenzymatic glucose sensors.

Highly-Sensitive Electrochemical Sensor for Glucose based on the Ordered Macroporous Polycysteine/Cu Film

A novel ordered macroporous polycysteine/Cu composite film (DOM PCE/Cu) was successfully prepared by electrochemical deposition method using polystyrene spheres as templates on a bare glassy carbon electrode (GCE). The structure and electrochemical properties of DOM PCE/Cu film were characterized. The DOM PCE/Cu composite film modified electrode exhibits good electrochemical catalytic activity toward the oxidation of glucose, which may be related to the structure of DOM PCE/Cu film. The non-enzymatic glucose sensor has a wide linear range from 2 μM to 2.9 mM, with a low detection limit of 0.8 μM. The modified electrode also has highly sensitive and fast amperometric (within 3 s) sensing of glucose, thus it can be used for the future development of non-enzymatic glucose sensor.

A highly sensitive non-enzymatic glucose sensor based on bimetallic Cu–Ag superstructures

Bimetallic Cu–Ag superstructures were successfully fabricated for the first time by using the natural leaves as reducing agent through a facile one-step hydrothermal process. Morphology, structure and composition of the Cu–Ag superstructures were characterized by field emission scanning electron microscopy (FESEM), transmission electron microscopy (TEM), X-ray diffraction (XRD), X-ray photoelectron spectra (XPS) and inductively coupled plasma-optical emission spectroscopy (ICP-OES), respectively. The results reveal that the Cu–Ag superstructure is bimetallic nanocomposite constructed by nanoparticles with low Ag content and shows a rough surface and porous flexural algae-like microstructure. By using a three-dimensional nickel foam as the scaffold, a novel non-enzymatic glucose sensor based on Cu–Ag nanocomposites has been fabricated and applied to non-enzymatic glucose detection. The as-prepared Cu–Ag nanocomposites based glucose sensor displays distinctly enhanced electrocatalytic activity compared to those obtained with pure Cu nanomaterials prepared with a similar procedure, revealing a synergistic effect of the matrix Cu and the doped Ag. Cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy indicate that the Cu–Ag superstructures based glucose sensor displays a fascinating sensitivity up to 7745.7μAmM−1cm−2, outstanding detection limit of 0.08μM and fast amperometric response (<2s) for glucose detection. Furthermore, the sensor also exhibits significant selectivity, excellent stability and reproducibility, as well as attractive feasibility for real sample analysis. Because of its excellent electrochemical performance, low cost and easy preparation, this novel electrode material is a promising candidate in the development of non-enzymatic glucose sensor.

CuO/Cu2O nanofibers as electrode materials for non-enzymatic glucose sensors with improved sensitivity

CuO nanofibers (NFs) were fabricated via the traditional electrospinning technique and subsequent thermal treatment processes. Using CuO NFs as precursors and glucose as a reducing agent, CuO/Cu2O NFs, with high surface areas and ultralong one dimensional (1D) nanostructures, were obtained by a partial reduction of CuO NFs. Comparing with pure CuO NFs, CuO/Cu2O NFs, as non-enzymatic electrode materials, showed a much higher sensitivity of 830 μA mM−1 cm−2 and a much wider detection range from 0.5 mM to 10 mM for the amperometric detection of glucose. The excellent electrocatalytic performances could be ascribed to the following advantages: (1) the CuO/Cu2O NFs with Cu(II)/Cu(I) multiple oxidation states system could promote the redox reactions between electrode materials and glucose, and the reactive sites became more active due to the synergic effect; (2) the surface of CuO/Cu2O NFs became smoother after partial reduction, resulting in less adsorption of the intermediates during the oxidation of glucose, generating the enlarged detection range. Therefore, the CuO/Cu2O composite NFs electrode materials, with a multiple oxidation states system, would be promising candidates for the development of non-enzymatic glucose sensors.

Synthesis of Graphite Oxide-Wrapped CuO Nanocomposites for Electrocatalytic Oxidation of Glucose

GO/CuO nanocomposite had been successfully synthesized by electrostatic interactions method. X-ray powder diffraction(XRD), Scanning electron microscopy(SEM), transmission electron microscope(TEM), selective-area electron diffraction(SAED), Fourier transform infrared spectroscopy(FT-IR), and Raman spectra confirmed the structure of the CuO and GO/CuO nanocomposite. The property of GO/CuO nanocomposite for electrocatalytic oxidation of glucose was investigated by cyclic voltammetry. The experimental results indicate that the GO/CuO nanocomposite modified electrode allows highly sensitive and low working potential of glucose and is promising for the future development of non-enzymatic glucose sensors.

A non-enzymatic thermally reduced Cu nanoparticle based graphene-resorcinol benzaldehyde glucose sensor

A non-enzymatic graphene based resorcinol–benzaldehyde glucose sensor decorated with copper nanoparticles (Cu NPs) was developed by a fast thermal reduction method. Cu NPs were synthesised by stirring various concentrations of [Cu(NH3)2] with graphene based resorcinol–benzaldehyde sheets. Subsequently physically adsorbed Cu2+ were thermally reduced under Ar gas. The electrochemical behaviour of Cu NPs based electrodes was investigated by cyclic voltammetry, which shows a very high oxidation of glucose in a neutral solution. All electrodes can be applied for the quantification of glucose with a linear range of 0·30–30·0 μM. The Cu NPs displayed a synergistic effect towards the oxidation of glucose with high stability and selectivity, showing higher oxidation current and negative shift in peak potential. Characterisations were done by X-ray diffraction, thermogravimetric analysis and transmission electron microscopy. Besides, synthesis method is very simple, convenient, and fast, which is promising for the development of non-enzymatic glucose sensors.

Electrocatalytic activity of Cu2O nanocubes based electrode for glucose oxidation

A direct electrocatalytic activity of glucose oxidation on cuprous oxide modified glassy carbon electrode is reported. Cu2O nanocubes were synthesized by a simple wet chemical route in the absence of surfactants. Purity, shape and morphology of Cu2O are characterized by XRD, SEM, XPS and DRS-UV. The Cu2O nanocubes-modified glassy carbon electrode (GCE) exhibited high electrocatalytic activity towards glucose oxidation compared with bare GCE electrode. At an applied potential of +0.60 V, the Cu2O electrode presented a high sensitivity of 121.7 μA/mM. A linear response was obtained from 0 to 500 μM, a response time less than 5 s and a detection limit of 38 μM (signal/noise=3). The Cu2O nanocubes modified electrode was stable towards interfering molecules like uric acid (UA), ascorbic acid (AA) and dopamine (DA). In short, a facile chemical preparation process of cuprous oxide nanocubes, and the fabricated modified electrode allow highly sensitive, selective, and fast amperometric sensing of glucose, which is promising for the future development of non-enzymatic glucose sensors.

Improvement of sensitive Ni(OH)2 nonenzymatic glucose sensor based on carbon nanotube/polyimide membrane

An improved nonenzymatic glucose sensor was fabricated of Ni(OH)2 on carbon nanotube/polyimide (PI/CNT) membrane by a simple electrochemical method. Three different morphologies of Ni(OH)2 have been formed by changing the conditions used in synthesis process. The formation mechanism for Ni(OH)2 nanospheres was studied to provide a deep understanding of crystal growth. The electrochemical behaviors of different Ni(OH)2 nanostructures were investigated by cyclic voltammetry and chronoamperometry in alkaline solution. At an applied potential of +0.60V, the sensor based on PI/CNT–Ni(OH)2 nanospheres shows a high sensitivity of 2071.5μAmM−1cm−2 and a detection limit of 0.36μM (signal/noise=3). The proposed sensor exhibits high sensitivity, long-term stability and good reproducibility, and performs well for detection of glucose in human blood serums. Therefore, this novel fabrication method for glucose sensor is promising for the future development of nonenzymatic glucose sensors.

Easy Fabrication of a Sensitive Non-Enzymatic Glucose Sensor Based on Electrospinning CuO-ZnO Nanocomposites

An easy and sensitive non-enzymatic glucose sensor was fabricated based on CuO-ZnO composite nanofibers by electrospinning and subsequent thermal treatment that was optimized to obtain the best sensing properties. The morphology and structure of the composite metal oxide were characterized by scanning electron microscopy and Fourier transform infrared spectroscopy. The electrochemical and electrocatalytic properties of CuO-ZnO for glucose electro-oxidation were thoroughly investigated by cyclic voltammetry. In the amperometric detection of glucose under low applied potentials, the CuO-ZnO-modified Pt electrode exhibited an extraordinary detection limit of 0.126 μM, a wide dynamic range from 8.00 × 10−7 to 3.88 × 10−3 M, and excellent sensitivity of 463.7 μA/(mM·cm2). The CuO-ZnO/Pt electrode showed considerably higher electrocatalytic activity, excellent sensitivity, and fast amperometric sensing toward glucose oxidation. The sensor also showed good selectivity, long-term stability, and excellent reproducibility. The results can serve as a foundation for the development of non-enzymatic glucose sensors.

Nonenzymatic glucose sensing at ruthenium dioxide–poly(vinyl chloride)–Nafion composite electrode

Development of nonenzymatic glucose sensors with high reproducibility and stability is an urgent need to reduce cost of regular diabetic monitoring. Here, we have fabricated ruthenium dioxide–poly(vinyl chloride)–Nafion (RuO2–PVC–Nafion) composite for direct glucose sensing in sodium hydroxide and phosphate buffer nonenzymatically for the first time. The restricted activity of the RuO2–PVC film electrode in alkaline pH is extended to neutral pH using Nafion as an outer membrane, which reduces the distance between Ru active sites by bridging effect and improves the electrode stability. The catalytic rate, measured in terms of change of RuO2 resistance, is similar irrespective of the medium for the high temperature annealed RuO2 (700 °C), whereas the low temperature annealed RuO2 (300 °C) is highly sensitive for the change in the pH of the solution. This is revealed by observing large Michaelis–Menten kinetic constant KM for the RuO2 (700 °C) than the low temperature annealed RuO2 (300 °C) due to effective increase in the catalytic active sites similar to oxygen evolution reaction. Contrast to this, the buffer solution does not influence significantly the apparent KM observed for RuO2 (300 °C) and has greater impact on the high temperature 500 and 700 °C annealed RuO2 samples. Cyclic voltammetry, chrono amperommetry, and electrochemical impedance spectroscopy, scanning electron microscopy, Fourier transform infrared spectroscopy, and X-ray diffraction techniques are used for characterization of the sensor behavior. The RuO2–PVC–Nafion senses glucose selectively in the presence of potential interferences like fructose, galactose, mannose, sucrose, starch, uric acid, ascorbic acid, dopamine, and catechol in NaOH and phosphate buffer. Glucose sensing in the blood serum of the diabetic and nondiabetic patients is made. The results suggest that the RuO2–PVC–Nafion is a promising candidate for the development of nonenzymatic glucose sensors.

Improvement of sensitive CuO NFs–ITO nonenzymatic glucose sensor based on in situ electrospun fiber

CuO nanofibers (NFs), prepared by electrospinning and calcination technologies, have been applied for the fabrication of glucose sensors with high sensitivity and selectivity. Cu(NO3)2 and polyvinylpyrrolidone (PVP) composite nanofibers were initially electrospun on the surface of indium tin oxide (ITO) glass, and then the CuO NFs–ITO electrode was formed simply by removing PVP through heat treatment. The structures and morphologies of CuO nanofibers were characterized by X-ray diffraction, scanning electron microscopy and thermogravimetric analysis. The direct electrocatalytic oxidation of glucose in alkaline medium at CuO NFs–ITO electrode has also been investigated in detail with cyclic voltammetry, chronoamperometry and electrochemical impedance spectroscopy. The effects of NaOH concentration, electrospinning time, Cu(NO3)2:PVP mass ratios and calcination temperature on the response to glucose were investigated. Under optimized experimental conditions, the CuO NFs–ITO electrode produced high and reproducible sensitivity to glucose of 873μAmM−1cm−2. Linear responses were obtained over a concentration range from 0.20μM to 1.3mM with a detection limit of 40nM (S/N=3). The CuO NFs–ITO electrode also has good selectivity, stability and fast amperometic sensing of glucose, thus it can be used for the future development of non-enzymatic glucose sensors.