Wide Range Of Glucose Concentrations Research Articles

Comparability Evaluation of Three Benchtop Glucose Analyzers With the Recently Withdrawn YSI 2300 Stat Plus.

We compared the performance of three currently available laboratory benchtop glucose analyzers with the outgoing YSI 2300 Stat Plus. Plasma samples (100), across a wide glucose concentration range were analysed on the YSI 2500, Randox daytona+ (glucose oxidase) and EKF Biosen in a single laboratory and compared to the YSI 2300 Stat Plus. All three analyzers showed good agreement with the YSI 2300 Stat Plus, and only a small bias (≤1% YSI 2500 and Randox daytona+, 4.6% EKF Biosen) was observed for each analyzer. None of the three comparator analyzers were affected by either proportional or constant bias, thus no significant differences between the YSI 2300 Stat Plus and the comparator methods were identified. The results from this study suggest all could be considered as suitable reference laboratory glucose analyzers and replacements for the recently withdrawn YSI 2300 Stat Plus.

A-386 Performance assessment of Point of care testing for blood glucose: a 5 year review of EQA data

Abstract Introduction WEQAS is the largest External Quality Assessment (EQA) provider for the Point of Care Testing (POCT) market within the UK supplying samples and assessment to over 30 000 sites per month with over 20 Programmes across the entire Health care sector. All the Programmes are accredited to ISO 17043.The aim of the programme is to provide support to POCT co-ordinators, to identify non compliant sites and improve the analytical performance of users. Most of the programmes are designed to allow the full assessment of all the devices within the organisation at either monthly, bimonthly or quarterly intervals. A Co-ordinator in each organisation is given a Group Administrator function for the EQA website and maintains the database for its own organisation. The role of performance surveillance is therefore devolved to each individual Co-ordinator at a local level and monitored nationally by the EQA organiser. The powerful database gives POCT Co-ordinators a wealth of information on method and analyser performance both within their own organisation and between organisations. Organisation performance summary reports, distribution letters, non-compliance reports, poor performance reports and cumulative reports are generated from one system. The POCT Users are also provided with a simple traffic light system with clear action limits. For the POCT glucose programme one sample is distributed each month with samples covering a range of 2 to 28 mmol/l annually. Methods A review of performance was undertaken between January 2018 and January 2023 for the POCT glucose Programmes for a selection of devices. Devices that were no longer available were excluded as were devices with <50 users in the group. This represented data from 10 360 devices per month in 2018 and 12 277 in 2023. Performance was assessed as the coefficient of variation (CV%) for the device group after outlier exclusion and calculated for a wide range of glucose concentrations. Results For devices with CV less than 5% in 2018 there was generally no further improvement in performance, however at a glucose of 2 mmol/L an improvement in performance of 0.5to 3.5% was observed for the other devices. In 2018 CVs ranged from 3.7 to 12% and 3.1 to 8.3%% at 2.5 and 26 mmol/L respectively compared with 4 to 10.3% and 3.3 to 7.2% in 2022. Conclusion Although there were numerous examples where EQA identified poor performance at an individual user level, there was little evidence to suggest that the performance of POCT glucose devices had improved significantly over the last 5 years.

포도당 탈수소효소와 합성된 폴리루테늄 매개체를 이용한 전기화학적 포도당 감지

당뇨병의 정확한 진단을 위해 산업체에서는 2세대 포도당센서를 사용해왔다. 2세대 포도당센서의 전자전달 매개체는 철, 루테늄 및 오스뮴과 같은 VIII족 금속으로 이루어져 있으며 본 논문에서는 포도당 탈수소 효소(GDH) 와 감응하는 새로운 전자전달 매개체를 합성하였다. 전기화학적 포도당 센서용 polyvinylimidazole(PVI)-[루테늄(4,4"-diamino-2,2"-bipyridine)2Cl](PVI-[Ru(dam-bpy)2Cl]) 전자전달 매개체의 구조는 1H nuclear magnetic resonance, Fourier-transform infrared 및 ultraviolet-visible spectroscopy로 측정하였다. 또한, cyclic voltammetry와 multi-potential step을 사용하여 전기화학적 특성을 분석하였다. PVI-[Ru(dam-bpy)2Cl]은 GDH를 사용하여 전극을 제작하였고, 마지막으로, 광범위한 포도당 농도(1-40 mM)에서 전기화학적 선형성이 입증되었다. PVI-[Ru(dam-bpy)2Cl] 전자전달 매개체가 2세대 포도당 바이오센서로서 산업계에서 직접 사용될 수 있을 것으로 기대한다. Diabetes necessitates the use of reliable glucose sensors capable of preventing the onset of complications via accurate and timely diagnosis. Among such sensors is a second-generation glucose amperometric sensor that uses an electrochemical method and is based on a mediator that transfers electrons from the enzyme to the electrode. Group VIII metals, such as iron, ruthenium, and osmium, have conventionally been used, and are synthesized with both electron-withdrawing and -donating ligands. Among these mediators, hexaamineruthenium(III) transferred electrons generated by glucose via glucose oxidase (GOx) to the electrode, allowing glucose quantification. However, a measurement error of the GOx enzyme was recently discovered due to external oxygen interference; therefore, it is being replaced with the enzyme glucose dehydrogenase (GDH). Hexaamineruthenium(III) exhibited a low electron transfer efficiency due to electrons stolen during the reaction with the GDH enzyme. Thus, to solve this problem, herein we synthesized a polymer-based ruthenium mediator complex, viz. polyvinylimidazole-[ruthenium(4,4"-diamino-2,2"-bipyridine)2chloride] (PVI-[Ru(dam-bpy)2Cl]) for electrochemical glucose sensing. The structure of the new mediator was determined using 1H nuclear magnetic resonance, Fourier-transform infrared, and ultraviolet-visible spectroscopies. Furthermore, electrochemical properties were determined using cyclic voltammetry and a multi-potential step. PVI-[Ru(dam-bpy)2Cl] interacted favorably with GDH. Finally, electrochemical linearity was demonstrated with a wide range of glucose concentrations (1-40 mM). We anticipate that PVI-[Ru(dam-bpy)2Cl] can be used directly in the industry as a second-generation glucose biosensor.

A disposable enzymatic biofuel cell for glucose sensing via short-circuit current

It is essential to construct a biofuel cell-based sensor and develop an effective strategy to detect glucose without any potentiostat circuitry in order to create a simple and miniaturized device. In this report, an enzymatic biofuel cell (EBFC) is fabricated by the facile design of an anode and cathode on a screen-printed carbon electrode (SPCE). To construct the anode, thionine and flavin adenine dinucleotide-dependent glucose dehydrogenase (FAD-GDH) are covalently immobilized via a crosslinker to make a cross-linked redox network. As a cathode, the Pt-free oxygen reduction carbon catalyst is employed alternative to the commonly used bilirubin oxidase. We proposed the importance of EBFC-based sensors through the connection of anode and cathode; they can identify a short-circuit current by means of applied zero external voltage, thereby capable of glucose detection without under the operation of the potentiostat. The result shows that the EBFC-based sensor could be able to detect based on a short-circuit current with a wide range of glucose concentrations from 0.28 to 30 mM. Further, an EBFC is employed as a one-compartment model energy harvester with a maximum power density of (36 ± 3) μW cm− 2 in sample volume 5 μL. In addition, the constructed EBFC-based sensor demonstrates that the physiological range of ascorbic acid and uric acid shows no significant effect on the short-circuit current generation. Moreover, this EBFC can be used as a sensor in artificial plasma without losing its performance and thereby used as a disposable test strip in real blood sample analysis.

Non-enzymatic glucose sensor using nanostructured copper oxide thin films deposited by spray pyrolysis

Thin-film thickness effect on glucose sensitivity for a non-enzymatic sensor is affected by two main factors, film´s conductivity, and roughness. The thin-film thickness effect is studied with copper oxide films grown by spray pyrolysis. The film is deposited with thickness in the 83 ≤ τfilm ≤ 892 nm range on a nickel electrode and employed for glucose sensing in a three-electrode system as a working electrode. As the film thickness increases up to 434 nm, the signal stability and sensibility improve. For a greater thickness, the glucose sensibility starts to decrease smoothly. The sensibility increment from the thinnest film to our best condition is twofold from 0.25 to 0.47 mAmM−1/cm2, and a lineal behavior is observed for a wide glucose concentration range of 0–8 mM. This work shows that a simple solution-based technique such as spray pyrolysis can be employed to obtain functional glucose sensors.

Phytochemicals of mustard (Brassica Campestris) leaves tuned the nickel‐cobalt bimetallic oxide properties for enzyme‐free sensing of glucose

AbstractThe fabrication of enzyme‐free glucose sensors is highly demanded for the biological, clinical, and food applications. In this study, we have developed a green method for tuning the surface properties of nickel‐cobalt bimetallic oxide (NiCo2O4) by adding mustard (Brassica Campestris) leaves extract during hydrothermal growth. The mustard (Brassica Campestris) leaves extract is rich with a variety of phytochemicals, which can easily tune the surface properties of NiCo2O4 nanostructures, thereby paving the way toward the development of sensitive and selective non‐enzymatic glucose sensors. The effect of various amounts of mustard (Brassica Campestris) leaves extract (0–20 ml) was also studied to find out the optimal conditions for growing surface‐modified NiCo2O4 nanostructures. The morphology and crystalline structure of the nanomaterials were studied by scanning electron microscopy (SEM) and powder X‐ray diffraction (XRD) techniques, respectively. The presence of an increasing quantity of mustard (Brassica Campestris) extract keeps the crystalline structure and the morphology of the NiCo2O4 nanostructures unaltered but changes their dimensions. All nanostructures show the same cubic spinel structure of NiCo2O4 and a morphology of spherical urchins composed of nanorods, but the diameter of the urchins decreases from ~10 μm to several nanometers, thus increasing the surface area of the nanomaterial. Furthermore, NiCo2O4 nanostructures were deposited onto glassy carbon electrodes (CGE), showing excellent catalytic properties toward the enzyme‐free detection of glucose using cyclic voltammetry. Importantly, the intensity of the oxidation current peak was linear over a wide range of glucose concentrations (from 0.1 to 10 mM) and the limit of detection (LOD) was estimated around 0.001 mM. Additionally, NiCo2O4 nanostructures grown in the presence of 20 ml of mustard leaf extract demonstrated good repeatability and excellent selectivity for glucose, without interference by other components such as urea, lactic acid, uric acid, ascorbic acid, as well as potassium and sodium ions. The combined results attest that mustard leaf extract has high potential as a green approach to improve the electrochemical properties of nanostructured materials, and could be useful for a wide range of materials for future electrochemical applications.

Glucose-Stimulated Calcium Dynamics in Beta Cells From Male C57BL/6J, C57BL/6N, and NMRI Mice: A Comparison of Activation, Activity, and Deactivation Properties in Tissue Slices.

Although mice are a very instrumental model in islet beta cell research, possible phenotypic differences between strains and substrains are largely neglected in the scientific community. In this study, we show important phenotypic differences in beta cell responses to glucose between C57BL/6J, C57BL/6N, and NMRI mice, i.e., the three most commonly used strains. High-resolution multicellular confocal imaging of beta cells in acute pancreas tissue slices was used to measure and quantitatively compare the calcium dynamics in response to a wide range of glucose concentrations. Strain- and substrain-specific features were found in all three phases of beta cell responses to glucose: a shift in the dose-response curve characterizing the delay to activation and deactivation in response to stimulus onset and termination, respectively, and distinct concentration-encoding principles during the plateau phase in terms of frequency, duration, and active time changes with increasing glucose concentrations. Our results underline the significance of carefully choosing and reporting the strain to enable comparison and increase reproducibility, emphasize the importance of analyzing a number of different beta cell physiological parameters characterizing the response to glucose, and provide a valuable standard for future studies on beta cell calcium dynamics in health and disease in tissue slices.

How to fit a response current-concentration curve? Part (Ⅱ): Synergy of heterogeneous PANI@Ni(OH)2/NF towards high performance glucose sensing and a general semi-empirical model

• Utilized a flow of hydroxylation and polymerization to assemble NEGSs. • Advanced a heterogeneous PANI@Ni(OH) 2 /NF NEGS without any conductive adhesive. • PANI@Ni(OH) 2 /NF showed a high sensitivity in a wide glucose concentration range. • Set up a general semi-empirical model of current-concentration suitable for NEGSs. • The nonlinear i – c model significantly reduced errors caused by linear fitting. Herein a heterogeneous material PANI@Ni(OH) 2 /NF, hydroxylated nickel foam (NF) modified by polyaniline (PANI), was assembled via an easy-to-operate sequential method. The hydroxylation obviously improves the reaction rate from Ni(II) to Ni (III) and the modification notably decreases the interface resistance. Benefitting from the synergy of Ni(OH) 2 , NF, and PANI, by means of three-segment linear fitting, PANI@Ni(OH) 2 /NF shows a high sensitivity up to 2248.7 μA mM cm −2 , a low detection limit of 0.52 μM, and excellent selectivity for glucose sensing when the glucose concentration ( c R * ) is from 0.001 mM to 16.000 mM. Further, we deduced a general semi-empirical model to describe the relationship between current i ( c R * ) and c R * , which eliminated the errors near the junction of two adjacent lines obviously and boarded the detection range. By comparing with the multi-segment linear fitting and our previous formula, both the mean d -value of 0.164 mA and the SD of 0.0218 mA obtained from the model are the lowest, respectively. A similar comparison was carried out in literature data, and the results are also satisfactory.

Non‐Enzymatic Electrochemical Biosensing of Glucose Using Nanocomposites of Polyaniline Nanofibers and Silver

AbstractIn this study silver nanoparticles were dispersed over polyaniline nanofibers (nPANI) by simple chemical reduction of silver nitrate in the presence of nPANI, and the prepared nPANI/Ag nanocomposite was employed for sensitive and cost‐effective non‐enzymatic detection of glucose using a modified carbon paste electrode. Detailed structural, crystallographic and morphological characterization of nPANI/Ag was carried out by means of Fourier‐transform infrared spectroscopy, X‐ray diffractometry and scanning electron microscopy. The enhancement of charge transfer of nPANI upon incorporation of Ag nanoparticles was confirmed by electrochemical impedance spectroscopy, and the electrocatalytic efficacy of the nPANI/Ag nanocomposite towards oxidation of glucose in alkaline medium was proven by cyclic voltammetry. Crucially, chronoamperometry demonstrated a linear response of the nPANI/Ag‐based glucose sensor over a wide range of glucose concentrations from 100 μM to 10 mM with a lowest detection limit of 1,3 μM. The sensor had a good selectivity for glucose in the presence of common interfering biomolecules. The sensor also had a shelf‐life of several days and the response was repeatable for up to nine individual measurements.

Fabrication of stable electrospun blended chitosan-poly(vinyl alcohol) nanofibers for designing naked-eye colorimetric glucose biosensor based on GOx/HRP

In this study, designing of a stable electrospun blended chitosan (CS)-poly(vinyl alcohol) (PVA) nanofibers for colorimetric glucose biosensing in an aqueous medium was investigated. CS and PVA solutions were blended to acquire an optimum content (CS/PVA:1/4) and electrospunned to obtain uniform and bead-free CS/PVA nanofiber structures following the optimization of the electrospinning parameters (33 kV, 20 cm, and 1.2 ml.h−1). Crosslinking process applied subsequently provided mechanically and chemically stable nanofibers with an average diameter of 378 nm. The morphological homogeneity, high fluid absorption ability (>%50), thermal (<230 °C) and morphological stability, surface hydrophilicity and degrability properties of cross-linked CS/PVA nanofiber demonstrated their great potential to be developed as an eye-readable strip for biosensing applications. The glucose oxidase (GOx) and horseradish peroxidase (HRP) was immobilized by physical adsorption on the cross-linked CS/PVA nanofiber. The glucose assay analysis by ultraviolet-visible (UV–Vis) spectrophotometry using the same enzymatic system of the proposed glucose strips in form of absorbance versus concentration plot was found to be linear over a glucose concentration range of 2.7 to 13.8 mM. The prepared naked eye colorimetric glucose detection strips, with lower detection limit of 2.7 mM, demonstrated dramatic color change from white (0 mM) to brownish-orange (13.8 mM). The developed cross-linked CS/PVA nanofiber strips, prepared by electrospinnig procedure, could be easily adapted to a color map, as an alternative material for glucose sensing. Design of a practical, low-cost, and environmental-friendly bio-based CS/PVA testing strips for eye readable detection were presented and suggested as an applicable medium for a wide range of glucose concentrations.

Tamarindus indica seed-shell nanoparticles‑silver nanoparticles-Ceratonia silique bean gum composite for copper-micro mesh grid electrode fabrication and its application for glucose detection in artificial salivary samples

This study used a new approach to fabricate a glucose detection system based on nano-engineered biomaterials. The fabrication steps included strategic synthesis, integration and stabilization of biological and metal nanoparticles in superabsorbent hydrogel gum matrix. The design of the high-performance electrochemical biosensor platform includes copper-micro mesh grid electrode modified with polymer phase comprising of silver nanoparticles surface coroneted with Ceratonia silique locust bean gum (LBG), Tamarindus indica seed-shell nanoparticles and glucose oxidase (GOx). Fundamental assessment of catalytic properties of the nanobiocomposite films on copper grid probe were performed by cyclic voltammetry, amperometry, differential pulse voltammetry. Probes showed good repeatability, reproducibility, selectivity, and long-term stability. The GOx was well-immobilized and stabilized by C. siliqua nano-matrix, with 85% and 98% activity retention when stored at different condiions for 6 month and 3 months, respectively. The fabricated grid-platform exhibited linear response in a wide range of glucose concentration, with detection limit of 1.0 nM (S/N = 3) and sensitivity 38.7 mA nM−1 cm−2. The bionanomaterial-based sensor was successfully applied for ultra-low glucose detection in artificial salivary samples. The designed sensor, perhaps with further modifications, has potential for the next generation of sensing platform in various biological fluids especially for non-invasive glucose detection for diabetic patients.

Glucose-dependent activation, activity, and deactivation of beta cell networks in acute mouse pancreas tissue slices.

Many details of glucose-stimulated intracellular calcium changes in β cells during activation, activity, and deactivation, as well as their concentration-dependence, remain to be analyzed. Classical physiological experiments indicated that in islets, functional differences between individual cells are largely attenuated, but recent findings suggest considerable intercellular heterogeneity, with some cells possibly coordinating the collective responses. To address the above with an emphasis on heterogeneity and describing the relations between classical physiological and functional network properties, we performed functional multicellular calcium imaging in mouse pancreas tissue slices over a wide range of glucose concentrations. During activation, delays to activation of cells and any-cell-to-first-responder delays are shortened, and the sizes of simultaneously responding clusters increased with increasing glucose concentrations. Exactly the opposite characterized deactivation. The frequency of fast calcium oscillations during activity increased with increasing glucose up to 12 mM glucose concentration, beyond which oscillation duration became longer, resulting in a homogenous increase in active time. In terms of functional connectivity, islets progressed from a very segregated network to a single large functional unit with increasing glucose concentration. A comparison between classical physiological and network parameters revealed that the first-responders during activation had longer active times during plateau and the most active cells during the plateau tended to deactivate later. Cells with the most functional connections tended to activate sooner, have longer active times, and deactivate later. Our findings provide a common ground for recent differing views on β cell heterogeneity and an important baseline for future studies of stimulus-secretion and intercellular coupling.NEW & NOTEWORTHY We assessed concentration-dependence in coupled β cells, degree of functional heterogeneity, and uncovered possible specialized subpopulations during the different phases of the response to glucose at the level of many individual cells. To this aim, we combined acute mouse pancreas tissue slices with functional multicellular calcium imaging over a wide range from threshold (7 mM) and physiological (8 and 9 mM) to supraphysiological (12 and 16 mM) glucose concentrations, classical physiological, and advanced network analyses.

A New Possibility for Fermentation Monitoring by Electrical Driven Sensing of Ultraviolet Light and Glucose.

Industrial fermentation generates products through microbial growth associated with the consumption of substrates. The efficiency of industrial production of high commercial value microbial products such as ethanol from glucose (GLU) is dependent on bacterial contamination. Controlling the sugar conversion into products as well as the sterility of the fermentation process are objectives to be considered here by studying GLU and ultraviolet light (UV) sensors. In this work, we present two different approaches of SnO2 nanowires grown by the Vapor–Liquid–Solid (VLS) method. In the GLU sensor, we use SnO2 nanowires as active electrodes, while for the UV sensor, a nanowire film was built for detection. The results showed a wide range of GLU sensing and as well as a significant influence of UV in the electrical signal. The effect of a wide range of GLU concentrations on the responsiveness of the sensor through current–voltage based on SnO2 nanowire films under different concentration conditions ranging was verified from 1 to 1000 mmol. UV sensors show a typical amperometric response of SnO2 nanowires under the excitation of UV and GLU in ten cycles of 300 s with 1.0 V observing a stable and reliable amperometric response. GLU and UV sensors proved to have a promising potential for detection and to control the conversion of a substrate into a product by GLU control and decontamination by UV control in industrial fermentation systems.

Combining Electrospinning and Vapor-Phase Polymerization for the Production of Polyacrylonitrile/ Polypyrrole Core-Shell Nanofibers and Glucose Biosensor Application.

In this work, polyacrylonitrile (PAN) nanofiber mats coated with conductive polypyrrole layers were produced at the surface of gold electrodes by a two-step approach combining electrospinning and vapor phase polymerization. In the first step, smooth and uniform PAN fibers exhibiting an average diameter of 650 ± 10 nm were generated through electrospinning of 12 wt% PAN solutions. The electrospun PAN fibers were impregnated with iron(III)tosylate (FeTos), annealed at 70°C and used as a robust and stable template for the growth of a thin layer of conductive polymer by co-polymerizing pyrrole (Py) and pyrrole-3-carboyxylic acid (Py3COOH) vapors under nitrogen atmosphere. The carboxyl groups introduced in polypyrrole coatings enabled further covalent binding of a model enzyme, glucose oxidase. The effect of different parameters (concentration of FeTos into the immersion solution, time of polymerization, Py/Py3COOH molar ratio) on the PAN/PPy/PPy3COOH/GOx impedimetric biosensor response was investigated. In the best conditions tested (immersion of the PAN fibers into 20 wt% FeTos solution, polymerization time: 30 min, 1:2 Py/Py3COOH ratio), the biosensor response was linear in a wide range of glucose concentration (20 nM−2μM) and selective toward ascorbic and uric acids. A very low limit of detection (2 nM) compared to those already reported in the literature was achieved. This value enables the determination of glucose in human serum after a large dilution of the sample (normal concentrations: 3.6 mM−6.1 mM range).

916-P: Precision Evaluation of Clinical Laboratory Glucose Reference Systems

Background: In response to the discontinuation of the industry standard YSI 2300 STAT PLUS glucose analyser Lifescan, as a major manufacturer of blood glucose measurement systems, initiated a comparative evaluation of currently marketed point of care (POC) glucose measurement devices to identify a potential replacement comparator system within a clinical environment. Method: Four POC devices were selected for in-depth assessment. Glucose measurement precision is a key performance metric for a comparator device, with higher standard deviation and coefficient of variation values imparting greater measurement uncertainty to diabetes test systems. This laboratory assessment used venous whole blood samples collected in Lithium Heparin coated tubes and tested within 12 hours of blood draw. All potential sources of variation such as donor and operator were controlled to give a best-case indication of performance. Results: Precision data were generated for the YSI 2300 STAT PLUS and four POC devices. 20 replicates were obtained per device at each of four glucose concentrations (50, 100, 200 and 500 mg/dL). The Abbott i-STAT Alinity (using CG8+ cartridge) demonstrated consistently lower standard deviation and coefficient of variation values when compared to the YSI 2300 STAT PLUS and other tests systems. Conclusions: A comparison of four currently marketed POC devices indicated that only one demonstrates precision performance that is equivalent or better than the YSI 2300 STAT PLUS across a wide range of glucose concentrations and thus is a strong candidate as a replacement clinical comparator system. Disclosure S. Phillips: Employee; Self; LifeScan, Inc. Employee; Spouse/Partner; LifeScan, Inc. S.J. Setford: Employee; Self; LifeScan Scotland. D.M. Shearer: None. A. Smith: Employee; Self; LifeScan, Inc. J.N. Ross: Employee; Self; LifeScan, Inc.

CuO/MoS2 nanocomposites for rapid and high sensitive non-enzymatic glucose sensors

Non-enzymatic amperometric glucose sensor is fabricated using CuO/MoS2 nanocomposites (CuO/M) by a facile method with high sensitivity. Cyclic Voltammetry (CV) studies of nanocomposites reveal the strong electrocatalytic activity for a wide range of glucose concentrations (0.1–10 mM) with a high current response in 0.1 M NaOH solution. The CuO/M modified electrode sensor shows high sensitivity (1055 μA/mM.cm2), rapid response (<2s), and lower detection limit (0.017 μμM) in the linear range of 35 μM–800 μM. The synergistic effect of MoS2 and CuO resulted in improved glucose electro-oxidation in alkaline solution. From the experimental results, it is inferred that modification with MoS2 could be a potential strategy to enhance the electrocatalytic properties of low-cost metal oxides.

Electrocatalytic glucose oxidation on a combinatorially electrodeposited cobalt-copper-nickel thin film material library

A Co–Cu–Ni thin film material library was fabricated using a modified 3D-printed Hull cell. Rather than previous one by one attempts a combinatorial approach was here not to miss the exact optimum performance composition. An optimum activity at Co-16 at.% Cu-12 at.% Ni for the electrocatalytic glucose oxidation was found by screening along the compositional spread using flow-type scanning droplet cell microscopy (FT-SDCM). Crystallographic properties, surface microstructure and surface topography were investigated along the entire compositional spread using X-ray diffraction (XRD), scanning electron microscopy (SEM) as well as atomic force microscopy (AFM), respectively. The entire compositional spread (Co 40–76 at.%, Cu 0–19 at.% and Ni 11–60 at.%) showed suitability for being used in glucose detection, as determined by cyclic voltammetric measurements. A maximum response for glucose electrooxidation was identified at a Ni content of 12 at.% with a current density value of 21.8 mA cm−2. The performance of a glucose sensor constructed using this identified thin film alloy was evaluated by localised amperometric detection. A linear behaviour was obtained for a wide range of glucose concentrations in the electrolyte solution between 1 mM and 100 mM. Additionally, the identified thin film alloy showed high stability, good electrooxidation reproducibility and high selectivity, thus indicating its suitability for being used as catalyst in glucose detection.

Fabrication of a biocompatible and continuous glucose biosensor with the poly(3,4-ethylenedioxythiophene) modified electrode

Abstract In this study, we have explored the potentiality of using GOx/AuNP/PEDOT(BSA)/Pt electrode as an implantable, long-lasting, and sensitive glucose biosensor. We have examined the performance of the electrode for glucose calibration with three electrochemical measurements, such as cyclic voltammetry, linear sweep voltammetry, as well as chronoamperometry, which all exhibited strong linear correlation between resulting signal and glucose concentration. In comparison, linear sweep voltammetry gave the best linear sensitivity, whose average was about 3.124 µA/mM/cm2 within a wide glucose concentration range from 0.416 to 50 mM. Meanwhile, the stability of the electrode was confirmed by a continuous glucose measurement in a 7-day period of time and the deviation was about 5%. The electrode was also biocompatibility according to the ISO109930-1 criterion. Furthermore, we have demonstrated that the oxidation of glucose on the GOx/AuNP/PEDOT(BSA)/Pt electrode was oxygen independent, therefore, it was not only easy to make but also feasible for continuous glucose monitoring systems.

How to fit a response current-concentration curve? A semi-empirical investigation of non-enzymatic glucose sensor based on PANI-modified nickel foam

Linear relationships between current response and glucose concentration have long been preferred in studying non-enzymatic glucose electrochemical sensors. The relationships, however, are usually not linear in a wide concentration range. Under given conditions, solution diffusion coefficient is an important factor leading to the nonlinearity. Herein we analyzed the effect of glucose concentration (c) on solution diffusion coefficient and proposed a new simple sensing current response (i) equation for expressing the relationship between i and c derived from the Cottrell formula and the diffusion coefficient formula. The semi-empirical equation enables the relationship to be represented accurately over a wide glucose concentration range instead of having to be divided into two or more linear segments. For verifying its applicability, we fabricated a non-enzyme glucose sensing electrode with polyaniline-modified nickel foam (PANI/NF) by oxidant-induced in situ polymerization. An i-c curve of the electrodes has been investigated and the simple semi-empirical equation can exactly match the measurement within a c range from 1.0μM to 20mM, the total mean squared error for glucose solution is 0.000. In addition, the experiments of sensitivity, limit of detection, reproducibility and stability in 0.1M NaOH all present satisfactory results, due to the 3D structure and plentiful surface active sites of NF, as well as the promotion of PANI for electrocatalytic glucose oxidation. Further, we prepared a PANI-hydroxyapatite-modified NF sensing electrode, and research results suggest that the semi-empirical equation is also appropriate for the three-component electrode system.

Advanced on-site glucose sensing platform based on a new architecture of free-standing hollow Cu(OH)2 nanotubes decorated with CoNi-LDH nanosheets on graphite screen-printed electrode.

The planned design of nanocomposites combined with manageable production processes, which can offer controllability over the nanomaterial structure, promises the practical applications of functional nanomaterials. Hollow core-shell nanostructure architectures represent an emerging category of advanced functional nanomaterials, whose benefits derived from their notable properties may be hampered by complicated construction processes, especially in the sensing domain. In this regard, we designed a highly porous three-dimensional array of hierarchical hetero Cu(OH)2@CoNi-LDH core-shell nanotubes via a quick, very simple, green, and highly controllable three-step in situ method; they were directly grown on a glassy carbon electrode to fabricate an enzyme-free glucose sensor. By virtue of an open structure containing a hollow conductive core and a highly porous catalytic active shell, which were both synthesized by the in situ method, hierarchical self-standing core-shell nanotubes were obtained. They provided an enlarged active surface area, highly accessible catalytic sites, faster electron transfer, effortless electrolyte ion diffusion pathways, and structural stability, thus leading to improved electrocatalytic performances and durability towards glucose electro-oxidation; this was reflected by the fast sensitive responses of the as-prepared sensor towards glucose and comparable results with the automatic biochemistry analyzer used in hospitals in real sample analysis. Moreover, the commercialization capability of the proposed sensor was evaluated analogously by directly grown hierarchical Cu(OH)2@CoNi-LDH core-shell nanotubes on graphite screen-printed exposable electrodes through a 3-step in situ method. Cu(OH)2@CoNi-LDH NS-NTs/GSPE showed accurate responses towards glucose, lack of any fouling effect of the electrocatalyst layer over a wide range of glucose concentrations and comparable results with that of a commercial glucometer in real sample analysis, which revealed high sensitivity, selectivity, and durability of the low-cost on-site sensor as well as excellent versatility of its fabrication method. Thus, the self-supporting, cost-affordable, facile, and fast electrode fabrication procedure with versatility and meticulous structural controllability presented in this research provides a new architecture for the advancement of high-performance electrochemical sensors and miniaturized detection devices.