High-performance Non-enzymatic Glucose Sensor Research Articles

Copper Oxide Decorated Zinc Oxide Nanostructures for the Production of a Non-Enzymatic Glucose Sensor

The glucose concentration in human blood can have a worrisome impact on human health, so the distribution of blood glucose contaminants in the human body is an important indicator that can be used to monitor diabetes. Diabetes affects many parts of the human body, such as neurological impairment, erectile dysfunction, and hardening of the arteries resulting in organ loss. In this study, cyclic voltammetry (CV) was used to process the electrical properties of a solution by preparing electrodes with CuO nanoparticles modified ZnO tetrapod nanostructures deposited on fluorine-doped tin oxide glass (CuO/ZnO/FTO). The measurements were processed in glucose solutions of different concentrations purposing for developing the sensitivity of the sensor. Different immersion times in the precursor copper sulfate solution were also used for preparing the electrode and carried out for electrochemical studies to adjust the electrode capability. The modified electrode, which was immersed in copper sulfate for 30 s, was efficient in detecting glucose molecules in different concentrations at the potential of +0.6 V. The rising slope is strongly and positively correlated with the concentration of glucose. One of the significant results is the indication that glucose concentration is linearly proportional to the current value of CV. After the measurement test with the addition of interference, the sensor can still identify the glucose concentration in the solution without being affected. This result proves that the sensor has considerable potential for developing into a high-performance non-enzymatic glucose sensor.

Copper Nanoparticles Decorated Halloysite Nanotube/Polyaniline Composites for High Performance Non-Enzymatic Glucose Sensor

Developing high-performance sensors for glucose detection is of great significance in clinical diagnostics and life science. This paper presents a non-enzymatic electrochemical glucose sensor with high performance. The halloysite nanotube/polyaniline (HNT/PANI) nanocomposite was obtained by chemical oxidation polymerization of aniline on the surface of halloysite nanotubes, then a highly sensitive non-enzymatic glucose sensor based on Cu nanoparticles decorated halloysite nanotube/polyaniline (Cu-HNT/PANI) nanocomposite was fabricated by in situ reduction of Cu precursor on HNT/PANI nanotubes under mild condition. Benefits from the high specific surface area and abundant active sites of the conductive substrate, the Cu-HNT/PANI nanocomposites modified glass carbon electrodes (GCE) exhibited significantly enhanced glucose sensing performance. The glucose sensor based on Cu-HNT/PANI composite demonstrated an excellent linear relationship in glucose concentrations range of 0.01–5 mM. The sensitivity in low concentration range (0.01–0.1 mM) reached 434.0 μA mM−1 cm−2 with the detection limit of 0.27 μM (S/N = 3). Besides, the Cu-HNT/PANI composites modified GCE exhibited extraordinary selectivity, stability and reproducibility in glucose sensing. Taking advantage of the low cost and mild synthesis conditions, Cu-HNT/PANI is a promising glucose-sensing material with broad application prospect.

Surface Selenylation Engineering for Construction of a Hierarchical NiSe2/Carbon Nanorod: A High-Performance Nonenzymatic Glucose Sensor.

As glucose (Glu) is an essential substance for metabolism as well as a symbol to diagnose diabetes, the demand of Glu sensors has increased significantly in recent decades. In this work, a hierarchical Ni-based electrochemical enzyme-free Glu sensor, namely, NiSe2/CNR (carbon nanorod), was engineered through a facile thermal treatment using dimethylglyoxime dinickel salt with selenium (Se) powder. The prepared NiSe2/CNR not only subtly introduces a hierarchical structure with rod-like carbon nanorods and rock-like NiSe2 nanoparticles, which are extremely helpful in offering a greater catalytic activity area and more catalytic active sites, but also incorporates the Se element to increase the inherent activity. The fabricated NiSe2/CNR exhibits distinguished performance for Glu detection in alkaline electrolytes with linear ranges of 0.5-411 μM and 411 μM to 6.311 mM, high sensitivities of 3636 μA mM-1 cm-2 at low concentrations, and 2121 μA mM-1 cm-2 at high concentrations, as well as a low detection limit of 380 nM (S/N = 3). It also possesses favorable reproducibility, stability, and long-term storage capacity. The practical feasibility of NiSe2/CNR was also validated by detecting Glu in human serum. Moreover, the prepared hierarchical NiSe2/CNR is of general interest for the construction of hierarchical Ni-based sensors.

Graphene oxide template based synthesis of NiCo2O4 nanosheets for high performance non-enzymatic glucose sensor

While glucose detection is ruled by enzyme-based glucose test strips, the chemically and thermally sensitive enzymes motivate the researchers to inspect chemically and thermally stable metal oxides as alternate sensing constituents for non-enzymatic glucose detection. Here, we report a synthesis of spinel nickel cobalt oxide (NiCo2O4) nanosheets-based catalyst for enzyme-free glucose sensing application via sonochemical approach using graphene oxide (GO) as nanosheets template and zeolitic imidazolate frameworks (ZIF-67) type nickel-cobalt metal-organic frameworks as oxide precursors (the catalyst named as gt-NiCo2O4 NSs). The physical characterization techniques confirmed that the as-synthesized gt-NiCo2O4 exhibited uniform porous and nanosheets morphology which can be obtained due to the ZIF-67 and GO template, respectively. Cyclic voltammetry and amperometric techniques employed for glucose oxidation at + 0.55 V using gt-NiCo2O4 NSs electrode in 0.1 M KOH. This sensor exhibited an excellent linear range (150 nM–8.86 mM), sensitivity (729.72 µA mM−1 cm−2) and lower detection level (7.35 nM; S/N ratio = 3) to glucose. Interestingly, the gt-NiCo2O4 NSs electrode displayed good recoveries to glucose in human blood serum and urine samples. Hence, the results indicates that gt-NiCo2O4 NSs is a promising electrode matrix with high sensitivity, excellent stability and good reproducibility that can enable the progress of enzyme-free glucose sensors.

Non-enzymatic sensing of glucose with high specificity and sensitivity based on high surface area mesoporous BiZnSbV-G-SiO2

It is profoundly appealing to build a common enzyme-free sensor for detection of glucose. We effectively synthesized a uniform and mesoporous BiZnSbV-G-SiO2 (BZSVGS) quaternary nanocomposite by electrodeposition on a Ni foam substrate. This BiZnSbV-G-SiO2@NF composite terminal has been used as an electrocatalyst for coordinated oxidation of glucose, in this manner acting as a high-performance non-enzymatic glucose sensor. Coordinated electrochemical estimation with the as-arranged anodes in PBS and urea showed that the BiZnSbV-G-SiO2 nanocomposite has a great electrocatalytic movement toward glucose oxidation in a neutral medium and a wide straight reaction from 0.06 to 0.1 μmol/L, a low detection constraint of 0.06 μmol/L (S/N = 3) at a low connected potential of + 0.20 V vs Ag/AgCl. This ponder moreover highlights the effect of diminishing anion electronegativity on upgrading the electrocatalytic proficiency by bringing down the potential required for glucose oxidation and long-term steadiness together with a brief reaction time of roughly 4 s highlights the promising execution of the BiZnSbV-G-SiO2@NF anode for non-enzymatic glucose detection with high accuracy and unwavering quality. Besides, it can be used for glucose location in human blood serum, promising its application toward assurance of glucose in genuine tests.

Solvothermal synthesis of hollow spherical CuCo2O4 as high-performance non-enzymatic glucose sensors

We prepared a hollow spherical CuCo2O4 material by solvothermal and calcination methods to use as an electrode material for non-enzymatic glucose electrochemical detection. Under alkaline conditions, the CuCo2O4/GCE electrode showed a high response to glucose; the highest sensitivity was 2929.4 μA mM−1 cm−2 in a detection range from 2 to 1800 μM, with a detection limit of 0.27 μM (S/N = 3). In addition, CuCo2O4/GCE had good selectivity and good stability in the presence of common interfering substances. Electrochemical test data showed CuCo2O4 is a promising and sensitive material for electrochemical detection of glucose.

High-performance non-enzymatic glucose sensors based on porous Co3O4 synthesized by coprecipitation method with the different precipitants

High-performance non-enzymatic glucose sensors based on porous Co3O4 synthesized by coprecipitation method with the different precipitants

Highly sensitive non-enzymatic electrochemical glucose sensor based on dumbbell-shaped double-shelled hollow nanoporous CuO/ZnO microstructures

A high-performance non-enzymatic glucose sensor based on hybrid metal-oxides is proposed. Dumbbell-shaped double-shelled hollow nanoporous CuO/ZnO microstructures (CuO/ZnO-DSDSHNM) were prepared via the hydrothermal method using pluronic F-127 as a surfactant. This structure is studied by various physicochemical characterizations such as scanning electron microscopy, X-ray diffraction spectroscopy, inductively coupled plasma atomic emission spectroscopy, elemental mapping techniques, X-ray photoelectron spectroscopy, and transmission electron microscopy. This unique CuO/ZnO-DSDSHNM provides both a large surface area and an easy penetrable structure facilitating improved electrochemical reactivity toward glucose oxidation. The prepared CuO/ZnO-DSDSHNM was used over the glassy carbon electrode (GCE) as the active material for glucose detection and then coated by Nafion to provide the proposed Nafion/CuO/ZnO-DSDSHNM/GCE. The fabricated glucose sensor exhibits an extremely wide dynamic range from 500 nM to 100 mM, a sensitivity of 1536.80 µA mM−1 cm−2, a low limit of detection of 357.5 nM, and a short response time of 1.60 s. The proposed sensor also showed long-term stability, good reproducibility, favorable repeatability, excellent selectivity, and satisfactory applicability for glucose detection in human serum samples. The achieved high-performance glucose sensing based on Nafion/CuO/ZnO-DSDSHNM/GCE shows that both the material synthesis and the sensor fabrication methods have been promising and they can be used in future researches.

Nickel sulfide nanoworm network architecture as a binder-free high-performance non-enzymatic glucose sensor.

Nickel sulfide nanoworm (Ni3S2 NW) network architecture was directly grown on the poly (3,4-ethylenedioxythiophene)-reduced graphene oxide hybrid films (PEDOT-rGO HFs) modified on glassy carbon electrode (GCE), acting as a binder-free sensor for high-performance non-enzymatic glucose monitoring. The sensor exhibited the satisfactory sensitivity (2123μAmM-1cm-2), wide linear range (15~9105μM), low detection limit (0.48μM), and rapid response time (< 1.5s) at a potential of 0.5V (vs. SCE) in 0.1M NaOH and possessed good selectivity, reproducibility, and stability. The enhanced electrocatalytic activity of the sensor towards glucose oxidation was attributed to the particular morphology, satisfying hydrophilic nature, strong combination between Ni3S2 NWs, PEDOT-rGO, and bare GCE. Moreover, it can be used for assaying glucose in human serum samples without dilution, indicating potential for clinical diagnostic applications. Graphical abstract Nickel sulfide nanoworms (Ni3S2 NWs)/poly (3,4-ethylenedioxythiophene)-reduced graphene oxide hybrid films (PEDOT-rGO HFs) were used to construct a binder-free high-performance non-enzymatic glucose sensor with satisfactory sensitivity, wide linear range, low detection limit, good selectivity, amazing reproducibility, and stability.

Solvothermal synthesis of Fe3O4 nanospheres for high-performance electrochemical non-enzymatic glucose sensor

Ferroferric oxide (Fe3O4) nanospheres have been synthesized via a facile solvothermal procedure to serve as an electrode material for high performance non-enzymatic glucose sensor. The as-synthesized Fe3O4 nanospheres with a uniform size from 16 to 18 nm, which can increase the reaction contact area and the active sites in the process of glucose detection. Benefiting from the particular nanoscale structure, the Fe3O4 nanospheres obviously enhanced the activity of electrocatalytic oxidation towards glucose. When the Fe3O4 nanospheres material was used for non-enzymatic glucose sensor, several electrochemical properties including the high sensitivity 6560 μA mM−1 cm−2 (0.1–1.1 mM), limit of detection 33 μM (S/N = 3) and good long-term stability were well demonstrated. Furthermore, Fe3O4 nanospheres electrode confirmed the excellent performance of selectivity in glucose detection with the interfering substances existed such as urea, citric acid, ascorbic acid, and NaCl. Due to the excellent electrocatalytic activity in alkaline solution, the Fe3O4 nanospheres material can be considered as a promising candidate in blood glucose monitoring.

Preparation and comparison of colloid based Ni50Co50(OH)2/BOX electrocatalyst for catalysis and high performance nonenzymatic glucose sensor

A novel nonenzymatic glucose sensor based on Ni50Co50(OH)2/BOX/FTO was constructed with high sensitivity and excellent selectivity when compared with Ni(OH)2/FTO and Co(OH)2/FTO. Ni50Co50(OH)2/BOX/FTO glucose sensor with nanometric size was made by using a simple colloidal method. The morphological demonstration of nanomaterials/nanoparticles were characterized by using TEM (transmission electron microscopy), energy dispersive X-ray spectroscopy (EDX), scanning electron microscopy (SEM), X-ray photoelectron spectroscopy (XPS), XRD and Raman, showing homogenously immersed particles with a size of less than 50 nm. Electrochemical measurements showed that colloidal based Ni50Co50(OH)2/BOX/FTO electrocatalyst possessed good catalysis capacity with low onset potential and excellent catalytic activity toward glucose. Nanocomposite has excellent sensitivity of 927.3 μA mM−1 cm−2, a wide linear range of 0.005 mM to 10.83 mM and LOD (low detection limit) of 0.017 μM (S/N = 3). Nanocomposites were applied for glucose determination in blood serum samples with standard addition; promising results were obtained with a standard deviation of ±1 to 2.5%. Nanocomposite show good reproducibility or recovery towards glucose. Ni50Co50(OH)2/BOX/FTO provide a new easy platform for electrochemical determination of glucose as nonenzymatic sensor.

Mesoporous ZnCo2O4 nanowire arrays with oxygen vacancies and N-dopants for significant improvement of non-enzymatic glucose detection

An efficient electrode for use in a sensitive, nonenzymatic catalyst for electro-oxidation of glucose is urgently needed to reduce the cost of regular diabetic monitoring. Finding a way to improve sensitivity while reserving the catalytic activity for glucose monitoring presents a big challenge. Replacing oxygen defects with nitrogen atoms in a nanostructured transition metal oxide can expose more catalytic active sites with improved electrical conductivity. Herein, a simple and scalable technique has been demonstrated to fabricate N-doped mesoporous ZnCo2O4 nanowire arrays (N-doped ZnCo2O4 electrode) through NH3-plasma treatment toward high-performance nonenzymatic glucose sensors. As a result, an N-doped ZnCo2O4 electrode exhibits ultra-sensitivity of 14,000 μA·mM−1 cm−2, a detection limit of 0.54 μM (S/N = 3), and a short response time of about 7.9 s. The impressive electrocatalytic performance originates from the filling of oxygen vacancies with nitrogen atoms in the mesoporous ZnCo2O4 nanowire arrays, which helps to accelerate the kinetics by increasing the pre-oxidation state of Co3+ and improving the electrical conductivity. Therefore, this study provides new insights into investigating the rational design of nanostructured transition metal oxides/hydroxides with tunable active sites and electrical conductivities for high-performance non-enzymatic glucose sensors.

Ultrathin CuxO nanoflakes anchored Cu2O nanoarray for high-performance non-enzymatic glucose sensor

Designing highly active material to fabricate high-performance glucose sensor was great importance for diabetes treatment. In this work, we develop a novel nanocomposite composed of multilevel nanostructure with ultrathin CuxO nanoflakes anchored on Cu2O nanowires, directly on Cu foil and its application as non-enzymatic glucose sensor. Due to more active sites endowed by the ultrathin CuxO nanoflakes, the as-prepared CuxO nanoflakes/Cu2O nanowires@Cu nanoarray exhibit high sensitivity (3.59 mA mM−1 cm−2), low detection limit (0.69 μM), high selectivity, fast amperometric response (~ 2 s) and excellent reliability in human serum. And the sensitivity of ultrathin CuxO nanoflakes/Cu2O nanowires@Cu nanoarray was 1.9-fold than that of Cu2O nanowires@Cu nanoarray. Such novel multilevel nanoarray synthesized by convenient method provides a facile way to design metal oxide nanomaterial for promising non-enzymatic glucose sensor.

Fabrication of porous NiMn2O4 nanosheet arrays on nickel foam as an advanced sensor material for non-enzymatic glucose detection

In this work, porous NiMn2O4 nanosheet arrays on nickel foam (NiMn2O4 NSs@NF) was successfully fabricated by a simple hydrothermal step followed by a heat treatment. Porous NiMn2O4 NSs@NF is directly used as a sensor electrode for electrochemical detecting glucose. The NiMn2O4 nanosheet arrays are uniformly grown and packed on nickel foam to forming sensor electrode. The porous NiMn2O4 NSs@NF electrode not only provides the abundant accessible active sites and the effective ion-transport pathways, but also offers the efficient electron transport pathways for the electrochemical catalytic reaction by the high conductive nickel foam. This synergy effect endows porous NiMn2O4 NSs@NF with excellent electrochemical behaviors for glucose detection. The electrochemical measurements are used to investigate the performances of glucose detection. Porous NiMn2O4 NSs@NF for detecting glucose exhibits the high sensitivity of 12.2 mA mM−1 cm−2 at the window concentrations of 0.99–67.30 μM (correlation coefficient = 0.9982) and 12.3 mA mM−1 cm−2 at the window concentrations of 0.115–0.661 mM (correlation coefficient = 0.9908). In addition, porous NiMn2O4 NSs@NF also exhibits a fast response of 2 s and a low LOD of 0.24 µM. The combination of porous NiMn2O4 nanosheet arrays and nickel foam is a meaningful strategy to fabricate high performance non-enzymatic glucose sensor. These excellent properties reveal its potential application in the clinical detection of glucose.

Three-dimensional porous MXene/NiCo-LDH composite for high performance non-enzymatic glucose sensor

In this paper, Nickel–Cobalt layered double hydroxide (NiCo-LDH) nanosheets were first in situ synthesized on MXene (Ti3C2) via a simple hydrothermal method, then glucose sensing performance based on three-dimensional porous MXene/NiCo-LDH nanocomposite was explored. At a working potential of 0.45 V (vs. SCE), the glucose sensor exhibits a wide linearity range (0.002 mM–4.096 mM), a low limit of detection (0.53 μM) and a rapid response (<3 s). Moreover, good selectivity, reproducibility and stability were also obtained. And the excellent performance can attribute to large area of contact of materials surface with glucose, fast electron transfer rate and easy diffusion of electrolyte provided by the novel 3D porous NiCo-LDH nanosheets on the conductive MXene substrate. Therefore, MXene/NiCo-LDH composites will be a candidate for electrochemical detection of glucose.

Facile preparation of three-dimensional NiO nanosheets array on carbon sphere and its high-performance nonenzymatic glucose detection

An ultrathin NiO nanosheets array loaded on carbon spheres were prepared by coprecipitation method and calcination approach. The as prepared NiO nanosheets contain high surface specific area due to their cross-sectional NiO three-dimensional structure which leads to more susceptible contacting between nanosheets and electrolyte. As the results, the reversible redox reaction should be accelerated. Moreover, NiO nanosheets array@carbon sphere (NiO@C) nanocompounds were mixed with Nafion solution and loaded onto glassy carbon electrodes (GCEs) to form a high performance non-enzymatic electrochemical glucose sensor. Cyclic voltammetric (CV) and Amperometric studies indicated NiO@C nanocompounds demonstrated excellent electrocatalytic activities for glucose detection.

Urea assistant growth of ammonium nickel phosphate (NH4NiPO4·H2O) nanorods for high-performance nonenzymatic glucose sensors

The ammonium nickel phosphate (NH4NiPO4·H2O) nanorods were achieved via a facile hydrothermal method with urea acting as both NH4+ source and molecule template. The obtained samples were characterized by XRD, SEM, TEM, and XPS, which showed typically anisotropic growth of the crystals with rod-like structures. The diameter of the NH4NiPO4·H2O nanorods is less than 50nm. The excellent glucose sensing performance was further obtained on the NH4NiPO4·H2O nanorods modified electrode, which have two corresponding linear regions of 5μM–2100μM and 2400μM–5700μM with the sensitivity of 459.4μAmM−1cm−2 and detection limit of 0.5μM (S/N=3) in the lower concentration range and the sensitivity of 250.2μAmM−1cm−2 and detection limit of 6μM (S/N=3) in the higher concentration range. Moreover, the as prepared sensor was also applied to analyze glucose concentration in serum samples, showing high possibility for real sample analysis. The highly nonenzymatic glucose sensing performance of NH4NiPO4·H2O nanorods may be due to its intrinsic layered crystal structure and rod-like morphology. The formation process of the NH4NiPO4·H2O nanorods and the corresponding glucose sensing mechanism were also discussed based on the analysis. These results could suggest that NH4NiPO4·H2O nanorods may be favorable electrochemical sensing materials for constructing non-enzymatic sensors.

Developing High-Performance Non-Enzymatic Glucose Sensors Based on Transition Metal Chalcogenides

Diabetes has long been recognized as one of the leading causes of death in the United States and worldwide second only to cancer and heart-related ailments. Diabetes is a silent killer and early stage diagnosis and controlling blood glucose level is the key to maintain and control the disease. Blood glucose levels are typically monitored with the help of glucose detection through electrochemical oxidation of glucose to gluconic acid or gluconolactone. Typically, in conventional glucose detectors, enzyme-based electrochemical sensors are used which suffers from several critical challenges including reduced efficiency and sensitivity, reduced shelf lives, lack of long-term stability (due to enzyme denaturation), high fabrication cost (due to complex enzyme purification steps), and high detection limit (due to less efficient indirect electron transfer). In this presentation we will discuss about designing high-efficiency direct glucose electrochemical sensors from transition metal chalcogenides using principles of materials chemistry, specifically, tuning the redox potential of the transition metal site. We will present several examples of high-efficiency chalcogenide based glucose sensors including CoNi2Se4-rGO nanocomposite, Ni3Te2, Cu2Se, and NiSe. These chalcogenide based electrocatalysts show high activity for glucose oxidation at very low potential (~0.35 - 0.45 V vs Ag|AgCl) with high sensitivity (exceeding 18 mA/mM cm2) and low limit of detection (LOD). These chalcogenides can offer direct electron transfer pathways over a wide potential range leading to much higher sensor efficiency. Moreover, the sensing performance of these electrocatalysts were tested in presence of common interferents present in physiological samples such as dopamine, ascorbic acid, lactose, etc., where it showed that glucose sensing was unaffected primarily because at such low potential, other biomolecules are not affected. In fact, the ability to oxidize glucose at such low potential is considered to be one of the most prominent novelty of these chalcogenide electrocatalysts, and the glucose oxidation potential of 0.35V (CoNi2Se4) is one of the lowest reported potential till date. The reason for such high activity for glucose oxidation was investigated through a series of experiments designed to alter the redox potential of the transition metal site either by changing the anion (selenide to telluride), transition metal doping (NiSe vs CoNi2Se4), or changing the d-electron occupancy (NiSe vs Cu2Se). Through these measurements we observed that on changing the electronegativity of the anion from selenide to telluride, the glucose oxidation potential could be reduced further due to transition metal site oxidation occurring at a lower potential. The transition metal site oxidation can be considered as the catalyst activation step which initiates the glucose oxidation. Transition metal doping at the active site also helped to redistribute the electron density thereby influencing catalyst activation and subsequent glucose oxidation steps. Interestingly, using highly occupied d-orbitals, slowed the electrocatalytic process. In this presentation we will discuss in details these structure property correlation and other factors influencing the electrocatalytic activity. We will also discuss how nanostructuring of the electrocatalysts on the other hand, increases the catalytic efficiency manifold by increasing the functional surface area for catalytic activity. Electrochemical measurements as well catalyst synthesis and processing will be discussed in details in this presentation.

Synthesis of wearable and flexible NiP0.1-SnOx/PANI/CuO/cotton towards a non-enzymatic glucose sensor

Ni-SnOx, PANI and CuO nanoparticles were synthesized on cotton fabric through chemical methods to make a new flexible high-performance non-enzymatic glucose sensor. FESEM, XRD, XPS, EDS and ATR analysis were employed to characterize the structure and the morphology of the nanomaterials. The high electrochemical performance of nickel and copper oxide and hydroxide on a conductive template leads to fabrication of a wearable and flexible cotton electrode with an excellent electrocatalytic activity to oxidize glucose. This hybrid system on the fabric as an electrode indicates a detection limit of 130 nM with wide linear range of 0.001–10 mM. The sensitivity was measured to be 1625 and 1325 μA mM−1 cm−2 for the ranges of 0.001–1 and 1–10 mM, respectively. Long-term stability, appropriate selectivity and reusability for many times make possibility for utilizing the fabricated sensor in the practical applications. The fabric is a wide linear range electrode with low detection limit to sense glucose concentration in the body fluids as well as the human blood that can be presumably suggested for designing other similar flexible types of sensor.

Enzyme-free glucose sensor based on layer-by-layer electrodeposition of multilayer films of multi-walled carbon nanotubes and Cu-based metal framework modified glassy carbon electrode

A high-performance nonenzymatic glucose sensor was successfully prepared by a layer by layer strategy through electrodeposition assembling multilayer films of Cu-metal-organic frameworks/multi-walled carbon nanotubes (Cu-MOF/MWNTs) modified glassy carbon electrodes (GCE). Different multilayer films of Cu-MOF/MWNTs modified GCE (Cu-MOF/MWNTs/GCE) were prepared by repeating the electrodeposition of MWNTs onto the GCE in an MWNTs solution (MWNTs/GCE) and electrodeposition of the Cu-MOF layer onto the MWNTs film surface to form a Cu-MOF/MWNTs composite layer in the crystallization solution of Cu-MOF. Results confirmed that this method to fabricate multilayer composite films on the GCE was fast and convenient, and that multilayer composite films were stable and unified. The electrode modified by the multilayer composite films could effectively increase the exposure of active sites and increase the surface area of reactive contact. The GCE modified by eight layers (four multilayers Cu-MOF/MWNTs films) showed the optimum catalytic performance in the oxidation of glucose. The novel glucose sensor exhibited a wider detection linear range of 0.5 μM–11.84 mM, with a detection limit of 0.4 μM and a sensitivity of 3878 μA cm−2 mM−1. Moreover, the electrochemical response of the sensor on glucose was fast (within 0.3 s) and stable, exhibited good selectivity and was free of interference.