Highly Sensitive Nonenzymatic Glucose Sensor Based on 3D Ultrathin NiFe Layered Double Hydroxide Nanosheets

As a promising electrode material, Ni‐based nanomaterials exhibit a remarkable electrochemical catalytic activity for nonenzymatic glucose sensors. In this paper, Nickel–Iron layered double hydroxide (NiFe‐LDH) film electrode with ultrathin nanosheets and porous nanostructures was synthesized directly on Ni foam (NF) by a one‐step hydrothermal method. The as‐obtained NiFe‐LDH electrode was adopted for glucose detection without further treatment. As an integrated binder‐free electrode for glucose sensor, the NiFe‐LDH/NF hybrid exhibits a superior sensitivity of 3680.2 μA mM⁻¹ cm⁻² with a low limit of detection (0.59 μM, S/N=3) as well as fast response time (<1 s). An excellent selectivity from potential interference species such as ascorbic acid, uric acid and Cl⁻ ions and acceptable stability were also achieved. The outstanding performance can be ascribed to the abundant electrochemistry active sites, facilitative diffusion of the electrolyte, high electron transfer rate and reliable stability architecture. Therefore, the NiFe‐LDH nanosheets demonstrate potential application in non‐enzymatic sensory of glucose.     

Magnetite Nanoparticles Bonded Carbon Quantum Dots Magnetically Confined onto Screen Printed Carbon Electrodes and their Performance as Electrochemical Sensor for NADH

Hybrid magnetite/carbon quantum dots (MagNP/C‐dots) were prepared and their characterization performed by high resolution transmission electron microscopy (HR‐TEM), X‐ray diffraction (XRD) and X‐ray photoelectron spectroscopy (XPS). Because of their suitable magnetization and electrochemical properties, they were used as versatile electrode modifiers after magnetically confining onto screen printed carbon electrodes (SPE), with the aid of a miniature external magnet. The reported strategy introduces a convenient procedure for assembling modified electrodes, since the nanoparticles can be easily released by removing the magnet. The non‐enzymatic magnetic biosensor showed excellent performance in the determination of NADH at the concentration range 2×10⁻⁷ to 5×10⁻⁶ mol L⁻¹, exhibiting a sensitivity of 0.15 μmol L⁻¹ and detection limit of 20 nmol L⁻¹. The MagNP/C‐dots/SPE sensor was also successfully applied for the determination of NADH in serum samples. The interference of typical biological molecules has also been investigated.     

Nonenzymatic Electrochemical Glucose Sensor Based on Novel Copper Film

Novel copper (Cu) film composed of pillar‐like structure was synthesized on indium‐doped tin oxide (ITO) substrate by electrodeposition in acetate bath with proline as additive for the first time and used to construct nonenzymatic glucose sensor. When applied to detect glucose, such prepared electrode showed low operating potential (0.4 V), high sensitivity (699.4499 µA mM⁻¹ cm⁻²), and fast response time (<3 s) compared with other Cu‐based electrodes. In addition, the prepared electrode also offered good anti‐interference ability to ascorbic acid, uric acid and acetaminophen. Present study provides new insights into the control of Cu film morphology for sensor fabrication.     

Electrochemical Synthesis of Shape-controlled Cu−Ni Nanocomposite and its Application for Nonenzymatic Glucose Sensing at Nanomolar Level

The electrodeposition method was firstly applied to obtain uniform cube-shaped copper nanoparticles on conductive glass (ITO), and then a layer of tiny nickel nanoparticles. A bimetallic composite electrode (Cu−Ni/ITO), characterized by TEM, XPS and XRD, was prepared to construct the non-enzyme electrochemical glucose sensor with high catalytic activity. The catalytic performance of Cu−Ni/ITO had been greatly improved, probably due to the synergistic bimetallic catalysis effect. The electrode had a satisfactory linear response in the range of 2.5×10⁻⁷ M to 2.6×10⁻³ M, with detection limit as low as 67 nM. Besides, Cu−Ni/ITO had good anti-interference ability and reproducibility, indicating the promising application for glucose detection in practical samples.     

An enhanced Nonenzymatic Electrochemical Glucose Sensor Based on Copper‐Palladium Nanoparticles Modified Glassy Carbon Electrodes

Novel copper‐palladium nanoparticles modified glassy carbon electrodes (Cu−Pd/GC) with enhanced nonenzymatic sensing for glucose were facilely prepared by one‐step electrodeposition. The structure and composition of the prepared nanoparticles were characterized by XRD, SEM, TEM and EDS, respectively. The electrode modified process was characterized by electrochemical impedance spectroscopy. Cyclic voltammetry and chronoamperometric experiments were used to evaluate the electrocatalytic activities of the electrodes toward glucose. The surface morphology and the electrocatalytic activities of Cu−Pd/GC was compared to Pd and Cu nanoparticles modified glassy carbon electrodes (Pd/GC and Cu/GC), respectively. Thanks to homogeneous distribution of Cu−Pd nanoparticles and the synergistic effect of Cu and Pd atoms, Cu−Pd/GC exhibited the highest sensitivity (298 μA mM⁻¹ cm⁻²) and the widest linear amperometric response (0.01 mM to 9.6 mM, R²=0.996) toward glucose compared to Pd/GC and Cu/GC. The detection limit of Cu−Pd/GC was 0.32 μM (S/N=3). In addition, the as‐prepared Cu−Pd/GC glucose sensor also exhibited exceptional capabilities of anti‐interference, reproducibility and long‐term stability. The as‐prepared sensor was also evaluated for determination of glucose concentration in human blood serum samples, which exhibited high reliability and accuracy, having great potential in clinical application.     

Electrochemical Investigation of Glucose on a Highly Sensitive Nickel‐Copper Modified Pencil Graphite Electrode

Novel nickel‐copper modified pencil graphite electrode (Ni?Cu/PGE) was fabricated and used as non‐enzymatic sensor for glucose determination. Ni and copper were electrodeposited on PGE using cyclic voltammetry. Morphology and composition of the modified PGE electrode were characterized by field‐emission gun scanning electron microscopy (FEG‐SEM), energy‐dispersive X‐ray spectroscopy (EDX) and Fourier transform infrared spectroscopy (FT‐IR). Electrochemical oxidation of glucose was evaluated by cyclic voltammetry as well as by amperometry. Electrochemical measurements indicate that the Ni?Cu/PGE exhibits a high sensitivity of 2951 μA mM^?1 cm^?2, and a low detection limit of 0.99 μM which are, respectively, three times higher and twice lower than that on Ni/PGE prepared in the same conditions. Moreover, Ni?Cu/PGE exhibits a wider linear range from 1 to 10000 μM with a rapid response time within 2 s. Moreover, Ni?Cu/PGE showed a remarkable stability. The electrode was successfully applied for determination of glucose concentration in human blood without significant interference from potential endogenic interferents. The good applicability of the elaborated sensor made Ni?Cu/PGE promising for the development of effective and inexpensive non‐enzymatic glucose sensor.     

Nickel Hydroxide Nanoparticles on Screen‐printed Electrodes as an Impedimetric Non‐enzymatic Glucose Sensor

In this study, the electrodeposition of nickel hydroxide nanoparticles onto a screen‐printed electrode (Ni(OH)₂/SPE) is described. Ni(OH)₂/SPE is proposed as an alternative non‐enzymatic glucose sensor based on Electrochemical Impedance Spectroscopy (EIS) measurements.The SPEs were modified by the cathodic electrodeposition of nickel, from a solution containing 0.010 M Ni(NO₃)₂ and 1 M NH₄Cl, at −1.3 V for 60 seconds. The SEM images show a uniform distribution of nickel spherical nanoparticles, with 60 nm average particle size. However, such morphology is not observed when the electrodeposition occurs in the absence of NH₄Cl. The electrochemical properties of the sensor were carefully evaluated by Cyclic Voltammetry. Ni(OH)₂/SPE shows a remarkable electrocatalytic behavior towards the oxidation of glucose in 0.1 M KOH. EIS measurements were carried out for Ni(OH)₂/SPE and a single‐frequency impedance method is proposed as transduction principle for glucose determination. The analysis of each parameter of complex impedance was performed. The best linear response was obtained for the module of impedance (|Z|) in the range of 0–2 mM of glucose at 0.1 Hz (R²=0.992) with a slope of 0.137 KΩ⁻¹⋅mM⁻¹ of glucose. Finally, Ni(OH)₂/SPE was utilized for quantification of glucose in blood samples.     

An Electrochemical Sensor Based on Ni(II) Complex and Multi Wall Carbon Nano Tubes Platform for Determination of Glucose in Real Samples

In the present paper, a stable and selective non‐enzymatic sensor is reported for determination of glucose (Glc) by using a carbon paste electrode modified with multiwall carbon nanotubes and Ni(II)‐SHP complex as modifier in an alkaline solution. This modified electrode showed impressive activity for oxidation of glucose in NaOH solution. Herein, Ni(II)‐SHP acts as a suitable platform for oxidation of glucose to glucolactone on the surface of the modified electrode by decreasing the overpotential and increasing in the current of analyte. Under the optimum conditions, the rate constant and electron transfer coefficient between electrode and modifier, were calculated to be 1.04 s⁻¹ and 0.64, respectively. The anodic peak currents indicated a linear dependency with the square root of scan rate and this behavior is the characteristic of a diffusion controlled process. So, the diffusion coefficient of glucose was found to be 3.12×10⁻⁶ cm² s⁻¹ due to the used number of transferred electron of 1. The obtained results revealed two linear ranges (5 to 190.0 μM (R²=0.997), 210.0 to 700.0 μM (R²=0.999)) and the detection limit of 1.3 μM for glucose was calculated by using differential pulse voltammetry (DPV) method. Also, the designed sensor was used for determination of glucose in the blood serum and urine samples. Some other advantages of Ni(II)‐SHP/CNT/CPE sensor are remarkable reproducibility, stability and selectivity which can be related to using nanomaterial of carbon nanotubes due to enhancement of electrode surface area.     

Cu and Ni Nanoparticles Deposited on ITO Electrode for Nonenzymatic Electrochemical Carbohydrates Sensor Applications

A novel non‐enzymatic carbohydrates sensor which was an indium tin oxide (ITO) glass electrode modified by nickel and copper nanoparticles (Cu/Ni/ITO) was developed by an electrochemical method. The crystallinity, morphology, electrochemical measurements and amperometric response of the as‐prepared ITO modified electrode were examined by the X‐ray diffraction (XRD), scanning electron microscopic (SEM), cyclic voltammetry (CV) and chronoamperometry, respectively. The Cu/Ni/ITO electrode had better electroactivity for glucose oxidation than that obtained using Cu/ITO, Ni/ITO, and Ni/Cu/ITO. The logistic regression equation, I_pa = (A ₁ – A ₂)/[1 + (C_glucose /x ₀)^p ] + A ₂, was used to fit the calibration curves of glucose aqueous solution concentrations and responsive current intensity. In research of other saccharides, such as fructose, lactose, sucrose, and maltose, which were detected by the Cu/Ni/ITO electrode, it was obvious that the Cu/Ni/ITO electrode was more sensitive to monosaccharides than disaccharides. Monosaccharides and disaccharides can be detected because the saccharides themselves had aldehyde group or be isomerized to an isomer having an aldehyde group in alkaline environment, and then aldehyde group produced carboxylic acid in the catalytic oxidation of the electrode, which lead to the change of electrode surface conductivity and the appearance of oxidation peak, and the alkaline environment further promotes the above reaction.     

Copper‐based Metal‐organic Framework for Non‐enzymatic Electrochemical Detection of Glucose

A non‐enzymatic electrochemical glucose sensor based on a Cu‐based metal‐organic framework (Cu‐MOF) modified electrode was developed. The Cu‐MOF was prepared by a simple ionothermal synthesis, and the characterizations of the Cu‐MOF were studied by Fourier transform infrared spectroscopy (FT‐IR), scanning electron microscopy (SEM), thermogravimetric analysis (TGA), single‐crystal X‐ray powder diffraction (SCXRD), and X‐ray powder diffraction (XRD). Electrochemical behaviors of the Cu‐MOF modified electrode to glucose were measured by differential pulse voltammetry (DPV). The electrochemical results showed that the Cu‐MOF modified electrode exhibited an excellent electro‐catalytic oxidation towards glucose in the range of 0.06 μM to 5 mM with a sensitivity of 89 μA/mM cm² and a detection limit of 10.5 nM. Moreover, the fabricated sensor showed a high selectivity to the oxidation of glucose in coexistence with other interferences. The sensor was satisfactorily applied to the determination of glucose in urine samples. With the significant electrochemical performances, MOFs may provide a suitable platform in the construction of kinds of electrochemical sensors and/or biosensors and hold a great promise for sensing applications.     

A Novel Enzymatic Glucose Biosensor and Nonenzymatic Hydrogen Peroxide Sensor Based on (3‐Aminopropyl) Triethoxysilane Functionalized Reduced Graphene Oxide

In the present study, a novel enzymatic glucose biosensor using glucose oxidase (GOx) immobilized into (3‐aminopropyl) triethoxysilane (APTES) functionalized reduced graphene oxide (rGO‐APTES) and hydrogen peroxide sensor based on rGO‐APTES modified glassy carbon (GC) electrode were fabricated. Nafion (Nf) was used as a protective membrane. For the characterization of the composites, Fourier transform infrared spectroscopy (FTIR), X‐ray powder diffractometer (XRD), and transmission electron microscopy (TEM) were used. The electrochemical properties of the modified electrodes were investigated using electrochemical impedance spectroscopy, cyclic voltammetry, and amperometry. The resulting Nf/rGO‐APTES/GOx/GC and Nf/rGO‐APTES/GC composites showed good electrocatalytical activity toward glucose and H₂O₂, respectively. The Nf/rGO‐APTES/GC electrode exhibited a linear range of H₂O₂ concentration from 0.05 to 15.25 mM with a detection limit (LOD) of 0.017 mM and sensitivity of 124.87 μA mM⁻¹ cm⁻². The Nf/rGO‐APTES/GOx/GC electrode showed a linear range of glucose from 0.02 to 4.340 mM with a LOD of 9 μM and sensitivity of 75.26 μA mM⁻¹ cm⁻². Also, the sensor and biosensor had notable selectivity, repeatability, reproducibility, and storage stability.     

Enhanced Electrocatalytic Activity of Ni‐CNT Nanocomposites for Simultaneous Determination of Epinephrine and Dopamine

A promising electrochemical sensor based nickel‐carbon nanotube (Ni‐CNT) modified on glassy carbon (GC) electrode had been developed and the properties of the modified electrode were characterized by multispectroscopic analysis. The fabricated sensor (GC/Ni‐CNT) electrode was utilized to determine the catecholamines such as epinephrine and dopamine simultaneously. Differential pulse voltammetry and amperometry were used to verify the electrochemical behavior of the studied compounds. The GC/Ni‐CNT based amperometric sensor showed a wide linear range and low detection limit with high analytical sensitivity of 8.31 and 6.61 μA μM^?1 for EP and DA, respectively which demonstrates better characteristics compared to other electrodes reported in the literature. Further, no significant change in amperometric current response was observed in presence of biological interference species such as glucose, cysteine, citric acid, uric acid and ascorbic acid in the detection of EP and DA. The utility of this GC/Ni‐CNT electrode was well established for the determination of EP and DA in human urine samples.     

Disposable Sandwich‐type Electrochemical Sensor for Selective Detection of Glucose Based on Boronate Affinity

A disposable sandwich‐type electrochemical sensor for selective detection of glucose was established. The primary receptor, 3‐aminophenylboronic acid was grafted covalently onto the surface of screen‐printed carbon electrodes through an in situ‐generated diazo‐reaction. Glucose was first captured by boronic acid group on the electrode, followed by captureing an electroactive ferroceneboronic acid (FcBA) as the secondary receptor to form bidentate glucose‐boronic complex. Electrochemical impedance spectroscopy was applied to characterize the construction of sandwich‐type disposable sensor. In the sandwich assay, current response of captured FcBA on the electrode was dependent on the concentration of glucose. The sandwich assay showed higher selectivity for glucose than that for fructose, mannose, galactose and other electroactive interferences including uric acid, ascorbic acid and dopamine, and exhibited a dynamic concentration range of glucose from 0.5 to 20.0 mmol L⁻¹. The disposable sensor demonstrated a good reproducibility with 2.2 % relative standard deviation (RSD). In addition, the disposable glucose sensor was used in detection of the trace glucose in the clinical urine samples.     

MWCNTs/Ionic Liquid/Graphene Quantum Dots Nanocomposite Coated with Nickel‐Cobalt Bimetallic Catalyst as a Highly Selective Non‐enzymatic Sensor for Determination of Glucose

In this work, a glassy carbon electrode (GCE) was modified with multiwall carbon nanotubes/ionic liquid/graphene quantum dots (MWCNTs/IL/GQDs) nanocomposite. Then, the nanocomposite was decorated with nickel‐cobalt nanoparticles (Ni?Co NPs), and it was used as a non‐enzymatic glucose sensor. Field emission scanning electron microscopy, X‐ray diffraction spectroscopy, and energy dispersive spectroscopy were employed to prove the electrodeposition of the Ni?Co NPs on the surface of MWCNTs/IL/GQDs/GCE. Also, cyclic voltammetric and amperometric methods were utilized for the investigation of the electrochemical behaviour of the Ni?Co NPs/MWCNTs/IL/GQDs/GCE for glucose oxidation. The novel amperometric sensor displayed two linear ranges from 1.0 to 190.0 μmol L^?1 and 190.0 to 4910 μmol L^?1 with a low detection limit of 0.3 μmol L^?1 as well as fast response time (2 s) and high stability. Also, the sensor showed good selectivity for glucose determination in the presence of ascorbic acid, citric acid, dopamine, uric acid, fructose, and sucrose, as potential interference species. Finally, the performance of the proposed sensor was investigated for the glucose determination in real samples. Ni?Co NPs/MWCNTs/IL/GQDs/GCE showed good sensitivity and excellent selectivity.     

Amperometric Glucose Biosensor Based on Electrochemically Deposited Gold Nanoparticles Covered by Polypyrrole

Graphite rod (GR) modified with electrochemicaly deposited gold nanoparticles (AuNPs) and adsorbed glucose oxidase (GOx) was used in amperometric glucose biosensor design. Enzymatic formation of polypyrrole (Ppy) on the surface of GOx/AuNPs/GR electrode was applied in order to improve analytical characteristics and stability of developed biosensor. The linear glucose detection range for Ppy/GOx/AuNPs/GR electrode was dependent on the duration of Ppy‐layer formation and the linear interval was extended up to 19.9 mmol L⁻¹ after 21 h lasting synthesis of Ppy. The sensitivity of the developed biosensor was determined as 21.7 μA mM⁻¹ cm⁻², the limit of detection – 0.20 mmol L⁻¹. Ppy/GOx/AuNPs/GR electrodes demonstrated advanced good stability (the t _1/2 was 9.8 days), quick detection of glucose (within 5 s) in the wide linear interval. Additionally, formed Ppy layer decreased the influence of electroactive species on the analytical signal. Developed biosensor is suitable for the determination of glucose in human serum samples.     

Tellurium Film Electrodes Deposited on Carbon and Mesoporous Carbon Screen‐printed Substrates for Anodic Stripping Voltammetric Determination of Copper

The performance of screen‐printed electrodes modified in situ with tellurium film for the anodic stripping voltammetric (ASV) determination of Cu(II) is reported. It was found that two types of screen‐printed substrates, namely carbon and mesoporous carbon, were optimal for this application. The selected in situ tellurium film modified electrodes were applied for the square wave ASV determination of copper at μg L⁻¹ concentration levels. Well‐defined and reproducible Cu oxidation stripping peaks were produced at a potential more negative than the anodic dissolution of tellurium. The highest sensitivity of Cu determination was achieved in 0.05 M HCl containing 50 μg L⁻¹ Te(IV) after 300 s of accumulation at −0.5 V. Using the optimized procedure, a linear range from 2 to 35 μg L⁻¹ of Cu(II) was obtained with a detection limit of 0.5 μg L⁻¹ Cu(II) (S/N=3) for 300 s of deposition time. Both sensors, carbon TeF‐SPE and mesoporous carbon TeF‐SPE, were successfully applied for the quantification of Cu in a certified reference surface water sample.     

Bimetallic CuCo Derived from Prussian Blue Analogue for Nonenzymatic Glucose Sensing

Bimetallic CuCo composites are prepared by calcinating copper hexacyanocobaltate precursor in N₂ atmosphere. The CuCo modified electrodes are fabricated for nonenzymatic glucose sensing in the alkaline electrolyte. The glucose can be directly electro-oxidized on the surface of the electrode catalyst mediated by the redox couples of Cu and Co. The optimal glucose sensor exhibits a high sensitivity (567 μA ⋅ mM⁻¹ ⋅ cm⁻²) in the range up to 825 μM with a detection limit of 3 μM and acceptable selectivity. The sensor can also be applied in serum samples. This work provides a facile and easily-scalable synthesis method of electrocatalysts for nonenzymatic glucose sensors.     

AgNP/Bi/Nafion‐modified Disposable Electrodes for Sensitive Zn(II), Cd(II), and Pb(II) Detection in Aerosol Samples

A new method for modifying electrodes with Ag nanoparticles (AgNPs) using electrospray deposition for sensitive, selective detection of Zn(II), Cd(II), and Pb(II) in aerosol samples when combined with Bismuth and Nafion coating and square‐wave anodic stripping voltammetry (SWASV) is reported. Carbon stencil‐printed electrodes (CSPEs) fabricated on a polyethylene transparency (PET) sheet were produced for an inexpensive, simple to fabricate, disposable sensor that can be used with the microliter sample volumes for analysis. Sensor performance was improved by modifying the electrode surface with electrospray‐deposited AgNPs. The use of electrospray deposition resulted in more uniform particle dispersion across the electrode surface when compared to drop‐casting. Using AgNP‐modified electrodes combined with Bi and Nafion, experimental detection limits (LODs) of 5.0, 0.5, and 0.1 μg L⁻¹ for Zn(II), Cd(II), and Pb(II), respectively, were achieved. The linear working ranges were 5.0–400.0 μg L⁻¹, 0.5–400.0 μg L⁻¹, and 0.1–500.0 μg L⁻¹ for Zn(II), Cd(II), and Pb(II), respectively. Interference studies showed Cu(II) was the only metal that interfered with this assay but inference could be eliminated with the addition of ferricyanide directly to the sample solution. This electrochemical sensor was applied for the simultaneous determination of Zn(II), Cd(II), and Pb(II) within source particulate matter (PM) samples collected on filters using an aerosol test chamber.     

Fabrication of Acid Violet 34/Nickel Hydroxide Ultrathin Film and Its Electrocatalytic Performance for Glucose

This article reports the fabrication of Acid Violet 34 (AV34)/nickel hydroxide nanosheets ultrathin film on the glassy carbon electrode (GCE) via the electrostatic layer‐by‐layer (LBL) technique, and its electrocatalytic oxidation for glucose was demonstrated. UV‐vis absorption and electrochemical impedance spectra indicate the uniform deposition of the LBL film, with a continuous and smooth film surface observed by SEM and AFM. The electrochemical performance of the ultrathin film was studied by cyclic voltammetry and chronoamperometry. The (AV34/Ni(OH)₂)₅ ultrathin film modified electrode displays a fast direct electron transfer attributed to the Ni²⁺/Ni³⁺ redox couple as well as remarkable electrocatalytic activity towards the oxidation of glucose. The linear response was obtained in the range 0.5–13.5 mM (R=0.9994) with a low detection limit (14 µM), high sensitivity (25.9 µA mM^?1 cm^?2), rapid response (less than 1 s) and excellent anti‐interference properties to the species including ascorbic acid (AA), uric acid (UA), acetamidophenol (AP) and structurally related sugars. Therefore, the AV34/Ni(OH)₂ ultrathin film can be potentially used as a feasible electrochemical sensor for the determination of glucose.     

An Arrayed Micro‐glutamate Sensor Probe Integrated with On‐probe Ag/AgCl Reference and Counter Electrodes

Complete all‐in‐one multi‐arrayed glutamate (Glut) sensors have been constructed on a silicon‐based micromachined probe composed of micro‐platinum (Pt) working electrodes, a micro‐silver/silver chloride (Ag/AgCl) reference electrode (RE), and a micro‐Pt counter electrode (CE). The OCP shift of the electrodeposited Ag/AgCl on‐probe micro‐reference electrode compared with a Ag/AgCl wire is <0.1 mV/h. The composition ratio of Ag, Cl, and Pt on the electrodeposited on‐probe micro‐reference electrode is observed to be 1.00 : 0.48 : 0.02 analyzed by EDS. The miniaturized amperometric Glut biosensors were constructed on working electrode sites (electrode area: ∼8.5×10⁻⁵ cm²) of the microprobe modified with glutamate oxidase (GlutOx) enzyme layers for the selective, fast, and continuous detection of L‐glutamate. The sensor selectivity towards common electroactive interferents has been improved significantly by coating the electrode surface with perm‐selective polymer layers, overoxidized polypyrrole (PPY) and Nafion®. The sensitivity, detection range, and response time of the proposed all‐in‐one Glut biosensors are 204.7±5.8 nA μM⁻¹ cm⁻² (N=5), 4.99–109 μM, and 2.7±0.3 sec, respectively and no interferent signals of AA and DA were observed. The sensor can be reused over 19 times of continuous repetitive operation (total measurement time: ∼4 hours) and the sensor sensitivity can retain up to four weeks of storage.