Non-enzymatic Determination Of Glucose Research Articles

Non-enzymatic Determination of Glucose in Artificial Urine Using 3D-µPADs through Silver Nanoparticles Formation

Patients with diabetes often experience blood glucose fluctuations, making monitoring crucial. Traditional blood sampling methods pose risks of infection and pain. An alternative non-invasive approach using urine tests has been explored. Recent studies highlight microfluidic paper-based analytical devices (µPADs) as convenient, simple, and easily fabricated tools for non-invasive glucose measurement. This study aims to develop a concept of measuring glucose in artificial urine using 3D-µPADs in a non-enzymatic manner by utilizing glucose as a reducing agent for silver nanoparticle (AgNPs) formation. Embedding three-dimensional connectors in µPADs links the sample and detection zones to limit reagent mixing and improve glucose detection resolution. The optimal conditions were NaOH 10 M, starch 1%, and AgNO3 30 mM, with sample and detection zone volumes of 10 and 9 µL, respectively. The fifth reaction sequence involved AgNO3 in the detection zone and a solution of glucose, NaOH, and starch in the sample zone at 1:1:1 volume ratio. The reagent drying time was 15 min, with immobilization once and reaction time of 9 min. The method showed excellent linearity (R2 = 0.9905), precision (%RSD = 4.27%), accuracy (77.32–92.58%), and limit of detection (11.11 mg/dL).

Confinement synthesis of few-layer MXene-cobalt@N-doped carbon and its application for electrochemical sensing

Herein, the few-layer Ti3C2Tx nanosheets loaded zeolitic imidazolate framework-67 nanoplates (Ti3C2Tx-ZIF-67) with a unique structure has been synthesized by surfactant control method, and then is employed as the core of precursor. A thin layer of polydopamine as the shell of precursor covered Ti3C2Tx-ZIF-67 forms a micro-nano reactor, leading to the confinement carbonization process. Consequently, a novel sensing material that few-layer Ti3C2Tx nanosheets loaded Co nanoparticles coated N-doped carbon (Ti3C2Tx-Co@NC) is obtained for the non-enzymatic determination of glucose. Owing to the impressive structure, the established glucose sensor based on Ti3C2Tx-Co@NC/glassy carbon electrode exhibits 0.5–100.0 μM of linear detection range and 66.8 nM of detection limit, which tends to detect low concentration of glucose. The synergistic few-layer Ti3C2Tx nanosheets, Co nanoparticles and NC are considered through a series of control experiments. First, few-layer Ti3C2Tx nanosheets provide a good transport channel for electron transfer, resulting in the lower steric hindrance. Second, Co nanoparticles provide active centers for the electrochemical detection. Third, N-doped carbon with conductivity and hydrophilia plays the role of stabilizing material structure to prevent the fragmentation of Ti3C2Tx and the agglomeration of Co nanoparticles. Such work proposes a confined strategy to develop MXene-ZIF-67-derived nanocomposite with high-performance structure.

Synthesis of Quaternary (Ni, Co, Cu)Se2 Nanosheet Arrays on Carbon Cloth for Non-Enzymatic Glucose Determination

Unlike transition metal oxides and sulfides, transition metal-based selenides display higher electrical conductivity, more electroactive unsaturated edge sites, and better chemical stability, which have found extensive usage in electrocatalysis. In this work, simple hydrothermal and solvothermal procedures were employed to synthesize quaternary (Ni, Co, Cu)Se2 nanosheet arrays on carbon cloth (CC) to measure glucose. The conductivity of the material can be effectively elevated by adding Se element to form selenides, and the synergistic effect between the three selenides can improve the electrocatalytic performance. Consequently, in the ranges of 0.01–600 μM and 600–9000 μM, respectively, the current response of the synthesized material to glucose concentration exhibited linear relationships. The sensor demonstrated excellent sensitivity and a low detection limit of 5.82 nM. Furthermore, the practical applicability of the constructed biosensor was proved by using it to quantify the amount of glucose in human serum.

Electrochemical sensors based on modified track–etched membrane for non-enzymatic glucose determination

In this research, a non-enzymatic sensor for electrochemical glucose detection based on modified poly(ethyleneterephthalate) track-etched membrane (PET TeMs) was firstly reported in the field of sensing of organic substances. The electrochemical sensors were obtained by photograft polymerization with 2-hydroxyethyl methacrylate (HEMA) and further formation of a polyelectrolyte complex with poly(allylamine) (PAlAm). 4-mercaptophenylboronic acid was functionalized on the surface of PET TeMs via Au-S bond and –OH group of polymerized HEMA to recognize glucose by formation of cyclic boronic ester. The modified PET TeMs were characterized by infrared spectroscopy, gas permeability test, scanning electron microscopy and energy dispersive analysis. Optimal parameters for graft polymerization, such as monomer concentration, polymerization time and distance from the UV-lamp were found. Electrochemical determination of glucose was done by square wave voltammetry. The non-enzymatic sensors for glucose detection showed a good linear relationship between the area under the oxidation peak and glucose concentration in the range from 0.1 mM to 8 mM with a low detection limit of 0.1 mM (R2 = 0.999). In addition, the sensors showed excellent reproducibility, repeatability and good selectivity for metal ions and ascorbic acid. The determination of glucose in apple juice and human blood serum demonstrated that the obtained sensors can be used in real samples with sufficient reproducibility of results.

High-performance enzyme-free glucose and hydrogen peroxide sensors based on bimetallic AuCu nanoparticles coupled with multi-walled carbon nanotubes

Interest in designing and manufacturing non-enzymatic biosensors is growing which stimulates the increased research efforts to explore innovative nanocomposites with highly catalytic activity. Here, the development of high-performance non-enzymatic glucose and hydrogen peroxide (H2O2) sensors based on bimetallic AuCu nanoparticles coupled with multi-walled carbon nanotubes (AuCu@MWCNTs) was achieved in this work. They were investigated by the cyclic voltammetry (CV), electrochemical impedance spectroscopy (EIS) and chronoamperometry (CA) methods separately. Benefiting from the synergistic effects of AuCu@MWCNTs, the proposed biosensors exhibited excellent performance such as low detection limits (1.3 nM for glucose, 0.1 nM for H2O2), broad linear ranges (8 nM-60 mM for glucose, 1 nM-4 mM for H2O2) and high sensitivities (362.3 μA·mM−1·cm−2 for glucose, 1335 μA·mM−1·cm−2 for H2O2). Besides, the AuCu@MWCNTs based electrodes provided excellent stability, repeatability and reproducibility. Based on the outstanding performance, they exhibited good reliability and accuracy in the detection of glucose in goat serum samples and real-time monitoring of H2O2 released by living cells. The present work suggests that the fabricated biosensor holds great potential for non-enzymatic glucose determination and real-time quantitative detection of H2O2 in biomedical applications.

BiVO4-based coatings for non-enzymatic photoelectrochemical glucose determination

• Non-enzymatic photoelectrochemical glucose sensors based on BiVO4 coatings were developed. • BiVO 4 coatings were deposited on fluoride-doped tin oxide (FTO) substrate by sol-gel method. • The effect of polyethylene glycol, urea, citric acid and PVA on photoelectrochemical activity was investigated. • Results revealed that morphology of BiVO 4 coatings plays critical role for sensitivity of sensor. • Sensitivity of some BiVO 4 coatings towards glucose was 0.0056 mA cm −2 mM −1 and limit of detection −6.87 μM. BiVO 4 is known as a promising material for the design of analytical systems dedicated for non-enzymatic photoelectrochemical (PEC) glucose determination. In this work BiVO 4 coatings were deposited on fluoride-doped tin oxide substrate by simple sol-gel method. The influence of different stabilizers, such as polyethylene glycol, urea, citric acid and polyvinyl alcohol (PVA) on the morphology and photoelectrochemical activity of the BiVO 4 coatings was investigated. X-ray diffraction, scanning electron microscopy, UV–vis optical absorbance and photoluminescence techniques were used to evaluate structural and optical properties of BiVO 4 films. PEC performance was characterized by means of voltammetry, electrochemical impedance spectroscopy and chronoamperometry. It is shown that the combination of urea and polyvinyl alcohol leads to the formation of BiVO 4 coatings with lower charge transfer resistance as well as higher affinity towards adsorption of glucose, resulting in higher sensitivity of these photoelectrodes in glucose sensing. Sensitivity of BiVO 4 coatings synthesized with urea (Bi_Urea) or with urea and PVA (Bi_Urea_PVA) towards glucose was 0.0033 mA cm −2 mM −1 and 0.0056 mA cm −2 mM −1 , respectively. The limit of detection was estimated to be 7.94 μM for Bi_Urea and 6.87 μM for Bi_Urea_PVA.

Enzyme-Free Electrochemical Sensors for in situ Quantification of Reducing Sugars Based on Carboxylated Graphene-Carboxylated Multiwalled Carbon Nanotubes-Gold Nanoparticle-Modified Electrode.

The reducing sugars of plants, including glucose, fructose, arabinose, galactose, xylose, and mannose, are not only the energy source of plants, but also have the messenger function of hormones in signal transduction. Moreover, they also determine the quality and flavor of agricultural products. Therefore, the in situ quantification of reducing sugars in plants or agriculture products is very important in precision agriculture. However, the upper detection limit of the currently developed sugar sensor is not high enough for in situ detection. In this study, an enzyme-free electrochemical sensor for in situ detection of reducing sugars was developed. Three-dimensional composite materials based on carboxylated graphene–carboxylated multi-walled carbon nanotubes attaching with gold nanoparticles (COOH-GR–COOH-MWNT–AuNPs) were formed and applied for the non-enzymatic determination of glucose, fructose, arabinose, mannose, xylose, and galactose. It was demonstrated that the COOH-GR–COOH-MWNT–AuNP-modified electrode exhibited a good catalysis behavior to these reducing sugars due to the synergistic effect of the COOH-GR, COOH-MWNT, and AuNPs. The detection range of the sensor for glucose, fructose, arabinose, mannose, xylose, and galactose is 5–80, 2–20, 2–50, 5–60, 2–40, and 5–40 mM, respectively. To our knowledge, the upper detection limit of our enzyme-free sugar sensor is the highest compared to previous studies, which is more suitable for in situ detection of sugars in agricultural products and plants. In addition, this sensor is simple and portable, with good reproducibility and accuracy; it will have broad practical application value in precision agriculture.

Nickel-gold bimetallic nanostructures with the improved electrochemical performance for non-enzymatic glucose determination

Bimetallic nanostructured electrodes are promising candidates for non-enzymatic glucose detection due to their excellent selectivity and high sensitivity. In this work, a bimetallic Ni/Au non-enzymatic glucose sensor was developed by the electrodeposition of nickel nanostructures on Au nanoparticles (NP). Physical vapor deposition followed by thermal annealing was used for the growth of seeding Au (NP) on fluorine doped tin oxide (FTO) substrates. The electrochemical growth of Ni nanostructures on the Au-seeded substrates led to enhanced electrochemical responses from the modified electrodes. Cyclic voltammetry results showed considerable improvement of the electrocatalytic activity of the Ni/Au bimetallic structure in comparison to monolithic Ni and Au structures due to the synergistic effect. The sensor showed two linear ranges of 5 μM–3.5 mM and 3.5–7 mM for glucose detection with the sensitivity of 893 (μA mM−1 cm−2). The low detection limit of 0.7 μM and the fast response time of 5 s was achieved. The selectivity, reproducibility and accuracy of the fabricated sensor in determination of human serum glucose suggest its potential for large-scale production as commercial non-enzymatic glucose detection.

Nanohybrid electrocatalyst based on cobalt phthalocyanine-carbon nanotube-reduced graphene oxide for ultrasensitive detection of glucose in human saliva

The current diabetes management systems require collecting blood samples via an invasive and painful finger pricking leading to the formation of callus, scarring and loss of sensibility to patients due to continuous monitoring. Therefore, a non-invasive and painless method of determining glucose levels would be desirable to diabetes patients who need constant monitoring. Saliva glucose measurement is a non-invasive alternative for diabetes management. A highly sensitive, stable, and selective non-enzymatic electrochemical sensor that can accurately quantify saliva glucose is required. A single-walled carbon nanotube/reduced graphene oxide/cobalt phthalocyanines nanohybrid modified glassy carbon electrode (GCE-SWCNT/rGO/CoPc) has been fabricated for the non-enzymatic determination of glucose in human saliva. The SWCNT/rGO/CoPc was characterized using various spectroscopic, microscopic, and electrochemical techniques. The synergistic effect between SWCNT, rGO, and CoPc facilitated excellent electron transfer process that improved the sensor sensitivity. The GCE-SWCNT/rGO/CoPc sensor exhibited two linear responses in the 0.30 μM to 0.50 mM and 0.50–5.0 mM glucose concentration ranges, and the detection limit was 0.12 μM. The sensor had an excellent saliva glucose detection sensitivity of 992.4 μA·mM−1·cm−2 and high specificity for glucose in the presence of other coexisting analytes. In addition, it showed good storage stability, reusability, and a fast response time of about 1.2 s. The GCE-SWCNT/rGO/CoPc nanohybrid electrode showed excellent potential for developing accurate, non-invasive, and painless glucose sensing.

Facile preparation of a highly sensitive non-enzymatic glucose sensor based on the composite of Cu(OH)2 nanotubes arrays and conductive polypyrrole

A novel amperometric non-enzymatic glucose sensor is designed by the facile preparation method. It is made by electrodeposition of Cu clusters and converting them to Cu(OH)2 nanotubes (Cu(OH)2NTs) arrays along with thin-film electro-polymerized of spindle-shaped polypyrrole (PPy@Cu(OH)2NTs), which have been doped by using sodium Benzene-1,3-disulfonate as an anion dopant. Various electrochemical methods investigate the electrochemical performance of the modified electrode toward glucose detection. Under the optimized conditions, a significant electrochemical response improvement is observed toward the electro-oxidation of glucose on the PPy@Cu(OH)2NTs electrode's surface relative to the Cu(OH)2NTs and the bare glassy carbon electrode. The designed electrode demonstrated an acceptable linear dynamic range in two wide ranges of 0.001 mM–1.78 mM and 1.78 mM–6.53 mM with high sensitivity of 910 µA mM−1 cm−2 and 675 µA mM−1 cm−2, respectively. The results are shown a low detection limit of 0.35 µM. Besides high sensitivity, this sensor represented good reproducibility and repeatability for glucose analysis and also provided relevant results for the non-enzymatic glucose determination in clinical preparations. This system also exhibits high selectivity for glucose oxidation that almost no signal was detected from interferences such as ascorbic acid, dopamine, uric acid, and chloride ions, demonstrating its great potential as a non-enzymatic glucose sensor. The superb sensing performance is ascribed to the sufficient catalytic sites of scroll-like Cu(OH)2NTs arrays morphology and synergistic effect of the doped-polypyrrole, which improve the surface area and act as a conductive binder on the electrode surface.

A dual-template defective 3DOMM-TiO2-x for enhanced non-enzymatic electrochemical glucose determination

A defective three dimensionally ordered macro-mesoporous TiO2-X (3DOMM-TiO2-X) was successfully prepared through dual-template method and applied as non-enzymatic electrochemical glucose sensor. The introduced oxygen vacancies and Ti3+ defects through defect engineering, as well as the macro-mesoporous structure induced by dual template, synergistically improve the performance of glucose determination. The Nafion/3DOMM-TiO2-X/FTO electrode shows better current response to glucose than commercial P25 and 3DOM-TiO2. A two-stage wide detection linear range of 1 μM ~ 2.32 mM and 2.32 mM ~ 14.72 mM was observed, with the sensitivity of 14.11 μA mM−1 cm−2 and 3.44 μA mM−1 cm−2, detection limits of 0.15 μM and 0.63 μM (S/N = 3), respectively. The electrode also exhibits superior reproducibility, stability, and selectivity performance. Furthermore, a reactive oxygen species oxidation mechanism was proposed and investigated. The Nafion/3DOMM-TiO2-X/FTO electrode also exhibits the potential as a photoelectrochemical electrode. Our results indicate the feasibility of the strategies to enhance the sensing ability by improving electronic conductivity through constructing 3DOMM porous structure and defect engineering.

Copper-nickel oxide nanofilm modified electrode for non-enzymatic determination of glucose

CuxO-NiO nanocomposite film for the non-enzymatic determination of glucose was prepared by the novel modifying method. At first, anodized Cu electrode was kept in a mixture solution of CuSO4, NiSO4 and H2SO4 for 15 minutes. Then, a cathodization process with a step potential of -6 V in a mixture solution of CuSO4 and NiSO4 was initiated, generating formation of porous Cu-Ni film on the bare Cu electrode by electrodeposition assisted by the release of hydrogen bubbles acting as soft templates. Optimized conditions were determined by the experimental design software for electrodeposition process. Afterward, Cu-Ni modified electrode was scanned by cyclic voltammetry (CV) method in NaOH solution to convert Cu and Ni nanoparticles to the nano-scaled CuxO-NiO film. The electrocatalytic behavior of the novel CuxO-NiO film toward glucose oxidation was studied by CV and chronoamperometry (CHA) techniques. The calibration curve of glucose was found linear in a wide range of 0.04–5.76 mM, with a low limit of detection (LOD) of 7.3 µM (S/N = 3) and high sensitivity (1.38 mA mM-1 cm-2). The sensor showed high selectivity against some usual interfering species and high stability (loss of only 6.3 % of its performance over one month). The prepared CuxO-NiO nanofilm based sensor was successfully applied for monitoring glucose in human blood serum and urine samples.

Cobalt-copper bimetallic nanostructures prepared by glancing angle deposition for non-enzymatic voltammetric determination of glucose

A bimetallic nanostructure of Co/Cu for the non-enzymatic determination of glucose is presented. The heterostructure includes cobalt thin film on a porous array of Cu nanocolumns. Glancing angle deposition (GLAD) method was used to grow Cu nanocolumns directly on a fluorine-doped tin oxide (FTO) substrate. Then a thin film of cobalt was electrodeposited on the Cu nanostructures. Various characterization studies were performed in order to define the optimum nanostructure for the determination of glucose. The results showed remarkable boosting of the electrocatalytic activity of Co/Cu bimetallic structure compare to the responses achieved by the monometallic structures of Co or Cu. The sensor showed two linear response ranges for the determination of glucose at 0.55V in 0.1M NaOH, from 5μM-1mM and 2-9mM. The sensitivity was 1741 (μAmM-1cm-2) and 626 (μAmM-1cm-2), respectively, while the detection limit for a signal-to-noise ratio of 3 was found to be 0.4μM. The sensor exhibited excellent selectivity and was successfully applied to the determination of glucose in real human blood serum samples. Graphical Abstract Schematic representation of fabrication process of the glucose sensor of Co (Cobalt)/Cu (Copper) on Fluorine doped Tin Oxide (FTO). The current voltage plots show higher electrooxidation activity of the bimetallic nanostructure of Co/Cu/FTO relative to the bare Co/FTO.

A graphite pencil electrode with electrodeposited Pt-CuO for nonenzymatic amperometric sensing of glucose over a wide linear response range.

A disposable nonenzymatic glucose sensor was obtained by pulsed electrodeposition of Pt-CuO on a graphite pencil electrode (GPE). The morphology of the modified GPE was studied using SEM, and the chemical composition of the coating was examined by EDAX and XRD. The electrochemical response of the modified GPE was compared with individual copper- and platinum-modified GPEs. The electrodeposition parameters were optimized with respect to the electrocatalytic activity of the deposits towards glucose oxidation. Best operated at a working potential of 0.6V vs. Ag/AgCl, the sensor has a sensitivity of 2035μAmM-1cm-2, a 0.1μM detection limit and a wide linear response range that extends up to 25mM. It is highly selective for glucose in the presence of various exogenous and endogenous interfering species. Eventhough the requirement of alkaline medium for sensing is a limitation, easy fabrication procedure, very high sensitivity and selectivity, wide analytical range, and disposable sensor characteristics show potential application towards blood glucose determination. Graphical abstractSchematic representation of the Pt-CuO electrodeposited pencil graphite electrode for the nonenzymatic determination of glucose.

Synthesis of porous Co3S4 for enhanced voltammetric nonenzymatic determination of glucose

Porous Co3S4 was synthesized by a two-step hydrothermal method, and its morphology and structure were characterized by transmission electron microscopy and X-ray diffraction. Electrochemical investigations showed that a glassy carbon electrode modified with Co3S4 exhibits high electrocatalytic activity toward glucose in 0.2M NaOH solution. Figures of merit for this sensor include (i) a wide linear range (2.0μM to 1.1mM), (ii) a working potential near 0.52V (vs. Ag/AgCl), (iii) high sensitivity (346.7μAmM-1cm-2), and (iv) a 0.17μM detection limit. Graphical abstractPorous Co3S4 was explored as electrocatalyst for glucose oxidation. It exhibits distinctly higher electrocatalytic activity toward glucose oxidation than Co3O4.

NH2‐GQDs‐Doped Nickel‐Cobalt Oxide Deposited on Carbon Cloth for Nonenzymatic Detection of Glucose

AbstractGraphene quantum dots (GQDs) play a vital role in improving electrocatalytic activity during constructing various composites. Among them, heteroatoms‐doped GQDs can further improve the conductivity and electrocatalytic properties of the composites. Herein, NH2‐GQDs‐doped NiCo2O4, grown on carbon cloth, is developed through one‐step hydrothermal process. The NH2‐GQDs doping significantly enhances its electrochemical performance due to its high electron transfer rate and synergistic effects. Severing as freestanding electrochemical electrode, the NH2‐GQDs/NiCo2O4 composite on carbon cloth exhibits low detection limit of 0.27 × 10−6 m and high sensitivity of 2521.33 µA mm−1 cm−2 for nonenzymatic determination of glucose. Furthermore, the fabricated glucose sensor shows outstanding selectivity and reproducibility. These results indicate that the NH2‐GQDs‐doped NiCo2O4 provides a convenient platform for nonenzymatic determination of glucose in the future.

Dendrite gold nanostructures electrodeposited on paper fibers: Application to electrochemical non-enzymatic determination of glucose

Preserving the three dimensions (3D) fibrous structure of paper-based working electrodes during the addition of conductivity to the filter paper sheets could be challenging. Protecting the paper electrode porosity could easily lead a higher surface area and therefore, higher sensitivity for electrochemical analyte sensing. Herein, various shapes of Au dendritic nanostructures have grown on the paper fibers by an electrodeposition process from HAuCl4 precursor and in the short time of 4.0 min. The effect of different experimental parameters including deposition potential, concentration of HAuCl4 solution and paper thickness on the electrodeposition results were investigated and discussed. The electrochemical behavior of the different deposited Au nanostructures was compared. Finally, the paper-based electrode modified by Au dendrites showed an efficient catalytic role for the non-enzymatic oxidation of glucose. The parameters effecting the performance of the sensor were investigated and optimized. Finally, it was used as sensor for measurement of glucose. The obtained linear calibration curve for the designed biosensor showed a wide concentration range of 10.0 μM to 15.0 mM with the limit of detection of 0.6 μM.

A gold electrode modified with a gold-graphene oxide nanocomposite for non-enzymatic sensing of glucose at near-neutral pH values.

A nanocomposite was prepared from gold and graphene oxide via one-step electrodeposition and used to modify the surface of a gold electrode (Au-Gr/GE) that was then applied to non-enzymatic determination of glucose. The effects of deposition time and supporting substrate on the morphology, structure, and electrochemical properties of the nanocomposite were optimized. The morphologies and crystal structures were characterized by scanning electron microscopy, transmission electron microscopy, and X-ray diffraction. The results indicate that gold nanoparticles grew on the surface of two-dimensional graphene oxide. The electrocatalytic activity of the modified electrode towards glucose oxidation was evaluated by cyclic voltammetry and amperometric methods at pH7.4. The Au-Gr/GE, typically operated at a potential of 0.00V (vs. Ag/AgCl), has a linear response in the 0.05-14mM and 14-42mM glucose concentration range, high sensitivity (604 and 267μAcm-2mM-1) and a low detection limit (12μM). The modified GE was applied to quantify glucose in sweat where it exhibited excellent sensitivity and accuracy. Graphical abstract The gold electrode modified with a gold-graphene (Au-Gr/GE) is prepared via a direct electrodeposition. The Au-Gr/GE is used for glucose detection in the neutral solution and it can achieve the effect of non-intrusive detection.

Effect of B-site doping on Sr2PdO3 perovskite catalyst activity for non-enzymatic determination of glucose in biological fluids

For the first time, a sensitive, selective and durable non-enzymatic glucose electrode was introduced based on Au-doped strontium palladium nano-perovskite modified graphite sensor. The effect of the metal dopant type in B-site of Sr2PdO3 perovskite; (M: Ni2+, Cu2+, Au3+, and Pt2+) was evaluated. Sr2Pd0.7Au0.3O3 modified graphite sensor with molar concentration of dopant 0.3 showed the highest electro-catalytic activity for non-enzymatic glucose sensing. The high catalytic activity of Sr2Pd0.7Au0.3O3 is attributed to the inclusion of highly conductive Au3+ dopant, generation of extra oxygen vacancies, enhancement of electronic and ionic conductivity, and stabilization of the orthorhombic perovskite structure. The proposed non-enzymatic glucose sensor offered high performance in terms of amperometric measurements in real serum samples, wide concentration range; 0.2 μM–100 μM, high sensitivity; 1.44 × 104 μA mM−1 cm−2, low detection limit; 2.11 nM and anti-interference ability. Also, this sensor offered long term stability and good shelf time up to one month with repetitive usage.

Synthesis of Ni-Co Hydroxide Nanosheets Constructed Hollow Cubes for Electrochemical Glucose Determination.

Hierarchical Ni-Co double transition metal hydroxide nanosheets have been explored as an effective strategy for the design of nonenzymatic glucose sensors. Ni-Co hydroxide nanosheets constructed hollow cubes were successfully synthesized by using Cu2O cubes as templates and subsequently etched by Na2S2O3 to achieve a hollow cubic structure. The molar ratio between Ni and Co was tuned by varying the precursor ratio of NiCl2 and CoCl2. It was observed by transmission electron microscopy (TEM) that the increasing Ni precursor resulted in particle morphology, and the increasing ratio of the Co precursor resulted in more lamellar morphology. The sample with the composition of Ni0.7Co0.3(OH)2 displayed the best performance for glucose sensing with high selectivity (1541 μA mM–1 cm–2), low detection limit (3.42 µM with S/N = 3), and reasonable selectivity. Similar strategies could be applied for the design of other electrode materials with high efficiency for nonenzymatic glucose determination.