Electrochemical Glucose Sensor Research Articles

Nanostructured metallic enzymes mimic for electrochemical biosensing of glucose

In many domains, the creation of nonenzymatic glucose sensors with robust electrocatalytic activity and chemical stability is indispensable. However, the design of nanoarchitecture transition metals and their nanocomposites as sensing interfaces for nonenzymatic recognition groups remains a formidable challenge. This review discusses the engineered nanoarchitecture transition metals used as non-enzymatic glucose sensors, with a particular focus on their applications characterized by low cost, high sensitivity, and long-term durability. Central to our discussion is the imperative of crafting nanostructured transition materials with expansive specific surface areas and well-defined active sites to serve as electrochemical sensing platforms. Our objective is to shed light on the enhanced electrochemical behavior toward glucose without reliance on mediators or templates. Leveraging advancements in nanotechnology, this review seeks to elucidate strategies for refining conventional nanostructures to optimize enzyme-free glucose sensing applications. Additionally, we delve into the inherent challenges and potential applications of these sensors for detecting glucose and outline ways to develop better non-enzymatic electrochemical glucose sensors.

Advancements in enzyme-free electrochemical glucose sensor materials

ABSTRACT Increased health awareness has called for better health monitoring devices, resulting in continuous research and advancement in glucose sensors. Innovations in both enzymatic and enzyme-free sensors (or non-enzymatic) are revolutionising diabetes control. While enzymatic sensors offer superior sensitivity and selectivity, enzyme-free sensors are preferred for stability and affordability, advancing the quest for rapid and accurate glucose tests. Progress in the development of enzyme-free glucose sensors is being achieved by improvements in electrode materials as well as sensor design. The selection of electrode materials is crucial in these sensors for attaining optimum values of sensing time as well as accuracy. Numerous electrode materials, including graphene, carbon nanotubes, metal oxides (such as platinum and gold), and conductive polymers, have been developed and studied by researchers to be employed in glucose sensors. Among the most critical factors being considered for developing glucose sensor materials is the selectivity for glucose molecules without interference due to the presence of another molecule. This article focuses on tracing recent developments in enzyme-free glucose sensor research, highlighting efforts to overcome limitations and drive innovation in glucose monitoring technology.

Honeycomb-shaped vertically aligned carbon nanotubes decorated with molybdenum trioxide as an electrochemical sensor for glucose

In this study, an electrode based on transition metal oxide molybdenum trioxide (MoO3) was fabricated and applied to electrochemical biosensing for glucose. In the process of making electrodes with relatively larger specific surface areas, an array of carbon nanotubes (CNTs) was deposited on a silicon substrate, and then, MoO3 was coated on the array of CNTs by chemical vapor deposition to produce a MoO3/CNTs/Si structure of three-dimensional electrochemical biosensing electrodes. Biosensing measurement was carried out in the concentration region from 20 μM to 7 mM of sodium hydroxide (NaOH). The highest sensitivity of 17.4 μA/μM cm2 was measured in the concentration range of 20–100 μM. The correlation coefficient of linear response (R2) was 0.9929, thus showing that MoO3/CNTs/Si is an excellent nonenzymatic glucose electrochemical sensor.

Development of Highly Sensitive and Selective Electrochemical Glucose Sensors Based on the Modification of the Surface, Structural, and Morphological Properties of ZnO Using Vitamin-B Complexes

Non-enzymatic electrochemical glucose sensors are particularly advantageous because of their simplicity, low cost, efficiency, and long storage life. ZnO structures were modified with water-soluble vitamin B12, B9, and B6 complexes in alkaline 0.1 M NaOH solutions to enhance glucose sensing. ZnO samples were hydrothermally synthesized using 5 mg fixed masses of B12, B9, and B6 complexes. X-ray diffraction, scanning electron microscopy, UV-visible spectrometry, and Fourier transform infrared spectroscopy were used to determine crystalline properties, morphology, and optical band gap. Zinc oxide obtained from vitamin B complexes had a hexagonal structure similar to wurtzite, modified nanorods on its surface, and a reduced optical band gap. The molecular weight, size, and number of functional groups vitamins also influenced surface and structural characteristics of ZnO. Zinc oxide from the B12 complex proved excellent for non-enzymatic glucose sensing in alkaline conditions. B12-derived ZnO glucose sensors have a linear range of 0.1 to 10 mM with a detection limit of 0.005 mM. In the glucose sensing process, a satisfactory level of stability, reproducibility, and selectivity was observed. Furthermore, it was found that ZnO derived from B12 had a high electrical conductivity, which facilitated electron transfer during glucose oxidation.

Enhanced sensing performance of flexible non-enzymatic electrochemical glucose sensors using hollow Fe3O4 nanospheres of controllable morphologies

Rapid and accurate monitoring of glucose concentration is of great significance in clinical diagnosis and treatment of diabetes and hence, it is necessary to develop glucose sensors of superior electro-catalytic capacity. Most literature utilize synergistic effect of nanocomposites to enhance glucose sensing performance, whereas it suffers from crucial restriction in physical and chemical characteristics of each constituents. Morphology of nanostructures significantly affects the electro-catalytic capacity, thus it is a novel route to improve glucose sensing performance to adjust morphology of nanostructures. Herein, we presented highly sensitive non-enzymatic electrochemical sensors for rapid and accurate glucose analysis with hollow Fe3O4 nanospheres (Fe3O4NSs) of controllable morphologies decorated on flexible fibers. The morphologies of the Fe3O4NSs were evaluated with quantitative parameters like diameter, roundness, roughness, skewness, and kurtosis acquired from SEM images and image processing algorithms, and their effect on the interfacial characteristics and the electro-catalytic capacity of the glucose sensors was investigated. Owing to the unique spherical nanostructures and superior catalysis, the Fe3O4NSs exhibit desirable solid/liquid interface for mass diffusion and abundant active sites for sufficient oxidation of glucose. Moreover, much rounder and rougher Fe3O4NSs of near Gaussian surface are readily produced at a higher Fe3+ concentration and result in favorable sensing performance. Accordingly, the optimal glucose sensor shows sensitivities of 96.1 ± 5.4 μA mM−1 cm−2 and 38.2 ± 2.2 μA mM−1 cm−2 over a preferable range of 0–18.0 mM, and a lower detection limit of 19.2 μM. Besides, the glucose sensors remain acceptable response after continuous testing for 20 times and repetitive bending for 50 times, and display superior selectivity to glucose and accurate analysis to practical samples. It is a facile and effective methodology to regulate the morphologies of the Fe3O4NSs for enhanced electro-catalytic capacity of glucose sensors.

Pt single-atom electrocatalysts at Cu2O nanowires for boosting electrochemical sensing toward glucose

In electrochemical biosensors, rational design and synthesis of high-performance electrochemical glucose sensors based on emerging single-atom catalysts (SACs) are paramount. Herein, a facile approach is proposed for dispersing single-atom doping of cuprous oxide (Cu2O) nanowires with Pt on a copper foam substrate (Pt1/Cu2O@CF) via the electrochemical deposition process. The specific nanostructure of the single-atom catalyst has been elaborately revealed with the aid of atomic resolution scanning transmission electron microscopy (STEM) and X-ray absorption fine structure spectroscopy (XAS). The as-fabricated Pt1/Cu2O@CF biosensor with satisfactory scalability exhibits a low limit of detection (1 μM), ultrahigh sensitivity (31.55 mA mM−1 cm−2), excellent selectivity, and robust reliability toward glucose. The first principles simulations reveal that Pt SAC is beneficial to the adsorption of glucose on the surface and further facilitates the electron transfer for the deprotonation process, resulting in high glucose sensing performance. This work sheds light on the applications of SACs for designing ultrasensitive electrochemical biosensors.

Functionalization of Carbon Nanofibers with an Aromatic Diamine: Toward a Simple Electrochemical-Based Sensing Platform for the Selective Sensing of Glucose.

Despite a variety of glucose sensors being available today, the development of nonenzymatic devices for the determination of this biologically relevant analyte is still of particular interest in several applicative sectors. Here, we report the development of an impedimetric, enzyme-free electrochemical glucose sensor based on carbon nanofibers (CNFs) functionalized with an aromatic diamine via a simple wet chemistry functionalization. The electrochemical performance of the chemically modified carbon-based screen-printed electrodes (SPCEs) was evaluated by electrical impedance spectroscopy (EIS), demonstrating a high selectivity of the sensor for glucose with respect to other sugars, such as fructose and sucrose. The sensing parameters to obtain a reliable calibration curve and the selective glucose sensing mechanism are discussed here, highlighting the performance of this novel electrochemical sensor for the selective sensing of this important analyte. Two linear trends were noted, one at low concentrations (0-1200 μM) and the other from 1200 to 5000 μM. The limit of detection (LOD), calculated as the (standard error/slope)*3.3, was 18.64 μM. The results of this study highlight the performance of the developed novel electrochemical sensor for the selective sensing of glucose.

Non-Enzymatic Glucose Sensors Composed of Polyaniline Nanofibers with High Electrochemical Performance.

The measurement of glucose concentration is a fundamental daily care for diabetes patients, and therefore, its detection with accuracy is of prime importance in the field of health care. In this study, the fabrication of an electrochemical sensor for glucose sensing was successfully designed. The electrode material was fabricated using polyaniline and systematically characterized using scanning electron microscopy, high-resolution transmission electron microscopy, X-ray diffraction, Fourier transform infrared spectroscopy, and UV-visible spectroscopy. The polyaniline nanofiber-modified electrode showed excellent detection ability for glucose with a linear range of 10 μM to 1 mM and a detection limit of 10.6 μM. The stability of the same electrode was tested for 7 days. The electrode shows high sensitivity for glucose detection in the presence of interferences. The polyaniline-modified electrode does not affect the presence of interferences and has a low detection limit. It is also cost-effective and does not require complex sample preparation steps. This makes it a potential tool for glucose detection in pharmacy and medical diagnostics.

Laser-induced graphene decorated with Ni[sbnd]Pt alloy nanoparticles for non-enzymatic electrochemical quantification of glucose

Enzyme-free electrochemical glucose (Glu) sensors, adopting electrochemically active catalysts, are of vital significance to effectively monitoring and analyzing the blood Glu level in diabetes diagnosis. Meanwhile, developing novel electrode substrates have been the hot research pot to meet the demand for constructing flexible sensors. In this work, porous laser-induced graphene (LIG) was prepared through a facile one-step laser-engraving technique on a polyimide thin film, and then used directly as the electrode. Furthermore, NiPt alloyed nanoparticles (NPs) were electrodeposited on the LIG electrode surface to gain the NiPt/LIG composite electrode, which was applied to construct the nonenzymatic electrochemical Glu sensor. The morphology, element and electrochemical performance of NiPt/LIG composite was characterized through various techniques. NiPt alloyed NPs were homogeneously distributed on the LIG scaffolds, which possess plenty of porous structure, high surface area and many active sites. The cooperative effect between the outstanding electrocatalytic capacity of NiPt alloyed NPs, the extraordinary electroconductibility of LIG and the numerous exposed active sites endow the NiPt/LIG sensor outstanding electrocatalytic performance for electrochemical oxidation of Glu. Under the most appropriate conditions, the obtained NiPt/LIG sensor was adopted to detect Glu, showing a broad detection concentration range of 0.5 μM to 2.1 mM and 2.1 mM to 5.6 mM, good sensitivities of 1.824 and 0.467 μA μM−1 cm−2, a low detection limit of 0.03 μM. The as-fabricated nonenzymatic Glu sensor also displays high selectivity, stability considering ageing effects under different environment conditions and prominent reproducibility. Additionally, this novel NiPt/LIG nonenzymatic Glu sensor was applied to quantify Glu successfully in blood serum and food samples and the results were in good agreement with that by UV–vis spectrophotometer, demonstrating high precision and accuracy as well as excellent recovery, showing good application prospects in Glu monitoring. This research confirmed the potential of exploiting NiPt/LIG as a highly sensitive Glu nonenzymatic electrochemical sensor and provided a practicable and suitable approach for construction of novel electrochemical sensors.

CuO Nano Leaves Based Non-Enzymatic Electrochemical Interface for Glucose Sensing

Copper oxide nanoleaves have attracted a lot of interest as potential components for electrochemical glucose sensors. Their distinctive structural features, including as a high surface-to-volume ratio and a customized shape, improve their electrocatalytic activities and increase the sensitivity and selectivity of glucose detection. An overview of the synthesis processes, structural characteristics, and electrochemical capabilities of copper oxide nanoleaves for glucose sensing applications are given in this abstract. Their prospective incorporation into portable and miniaturized sensor platforms is also examined, underlining the important contributions they have made to the field of point-of-care diagnostics and continuous glucose monitoring for diabetics.

Non-enzymatic Glucose Sensor Based on Ni(OH)2/NF Materials Using Different Pulse Voltammetry Technique

Non-enzymatic glucose sensors have gained significant attention owing to their potential for accurate and cost-effective glucose detection. Nanomaterials play a pivotal role in enhancing performance of non-enzymatic glucose sensor. In this study, a novel non-enzymatic glucose sensor based on Ni(OH)2/NF (nickel hydroxide/nickel foam) materials was developed using different pulse voltammetry technique. Chemical precipitation methods have been used to grow Ni(OH)2 nanostructures directly on a nickel foam electrode. The characterization of the synthesized materials was performed through field emission scanning electron microscopy (FESEM), energy dispersive spectroscopy (EDX), and X-ray diffraction (XRD). The performance of the Ni(OH)2/NF-based glucose sensor was evaluated through electrochemical measurements. Nanoscale hive-like structures of Ni(OH)2 with a diameter ranging from 450 to 530 μm and a thickness of 20 nm were formed on the NF surface. The sensor exhibited good performance, displaying a high sensitivity of 8.42mA.mM-1.cm-2 with a low detection limit of 0.84 μM. These results position the synthesized electrode as a promising contender for non-enzymatic electrochemical glucose sensors.

Tailoring the d-band center on Ru1Cu single-atom alloy nanotubes for boosting electrochemical non-enzymatic glucose sensing.

The development of cost-effective and highly efficient electrocatalysts is critical to help electrochemical non-enzymatic sensors achieve high performance. Here, a new class of catalyst, Ru single atoms confined on Cu nanotubes as asingle-atom alloy (Ru1Cu NTs), with aunique electronic structure and property, was developed to construct a novel electrochemical non-enzymatic glucose sensor for the first time. The Ru1Cu NTs with a diameter of about 24.0nm showed amuch lower oxidation potential (0.38V) and 9.0-fold higher response (66.5 μA) current than Cu nanowires (Cu NWs, oxidation potential 0.47V and current 7.4 μA) for glucose electrocatalysis. Moreover, as an electrochemical non-enzymatic glucose sensor, Ru1Cu NTs not only exhibited twofold higher sensitivity (54.9 μA mM-1cm-2) and wider linear range (0.5-8mM) than Cu NWs, but also showed alow detection limit (5.0μM), excellent selectivity, and great stability. According to theoretical calculation results, the outstanding catalytic and sensing performance of Ru1Cu NTs could be ascribed to the upshift of the d-band center that helped promote glucose adsorption. This work presents a new avenue for developing highly active catalysts for electrochemical non-enzymatic sensors.

Investigating and improving the water stability of ZIF-L-Co for electrochemical glucose sensors

More and more studies have shown that zeolitic imidazolate framework (ZIF) materials exhibit very high thermal stability, but poor aqueous stability, that limits their practical application. In this work, leaf-shaped ZIF-67 on the surface of foam nickel (namely as ZIF-L-Co/NF) is selected to deeply investigate the mechanism of water stability. The related reaction process of ZIF-L-Co/NF in water is proposed for the first time and demonstrated based on a series of characterizations. The results show that ZIF-L-Co/NF lost its skeleton after only 1 h in water, and completely converted into cobalt hydroxide (Co(OH)2) after 24 h. The reaction process is proved to be invertible via designed experiments. Considering invertible reaction, two strategies are proposed to improve the water stability of ZIF-L-Co, by (1) introducing second metal center Zn and (2) adding extra 2-methylimidazole (Hmim) to push the reaction process in reverse. Based on the above improving strategies, bimetallic ZIF-L-CoZn/NF(2:1) prepared by introducing the second metal Zn is applied as electrochemical sensor towards glucose, and exhibits high sensing performance with good sensitivity, selectivity, and wide detection range as glucose sensor. Experimental results demonstrate its excellent aqueous stability. This work provides a totally new viewpoint for the application of ZIF materials in aqueous conditions and perfects the characteristics of ZIF family.

Streamlined synthesis of superstructure Ni-benzimidazole MOFs: Glucose electrochemical analysis

The design and synthesis of efficient electrochemical sensors are crucial transformation technologies in electrochemistry. We successfully synthesize a three-dimensional Ni-metal–organic framework (MOF) nanostructured material with a superior architecture using benzimidazole and nickel nitrate as precursors at room temperature which is being applied in glucose electrochemical sensors. The reaction mechanism of M-6 during glucose detection is thoroughly studied using various characterization techniques, such as in situ Raman spectroscopy, in situ ultraviolet–visible spectrophotometry, synchrotron radiography, X-ray diffraction, X-ray photoelectron spectroscopy, and scanning electron microscopy. The research findings demonstrate that the M-6 material exhibits high sensitivity for glucose detection, with a sensitivity of 2199.88 mA M−1 cm−2. This study provides an important reference for designing more efficient electrochemical reaction systems and optimizing material performance. Furthermore, the superstructural design offers new ideas and possibilities for the development and application of similar materials.

High-performance rGO@CNTs@AgNbS nanocomposite electrode material for hybrid supercapacitor and electrochemical glucose sensor

Due to its outstanding ability to store energy, the hybrid energy storage system known as the supercapattery has attained a lot of attention. These devices give extraordinary power and energy densities than supercapacitors and batteries. In this research, a hydrothermal method is used to synthesize a composite material with equal amounts of both components (a 50/50 weight ratio) of silver niobium sulfide and doped with rGO@CNT. Its potential is evaluated using a variety of electrochemical investigations, including galvanostatic charge–discharge and cyclic voltammetry measurements. The rGO@CNT@AgNbS is considered the most attractive material for electrodes based on the electrochemical analysis results, with a specific capacity of 2750 C/g. Additional investigations, including cyclic voltammetry (CV), galvanostatic charge–discharge (GCD), XRD, SEM, and a 15000-cycle stability test, are carried out to better understand this asymmetric device. The device displayed a significant energy density of 65 Wh kg−1 and a fantastic power density of 2229 W /k g . Besides, the composite devices are used as an electrochemical glucose sensor to detect glucose. The device showed an extraordinary sensitivity (greater than 95%) up to a small level of glucose. This study demonstrates the excellent achievement of composite rGO@CNT@AgNbS electrodes for supercapattery applications, with tremendous power and energy densities.

Enzyme-chitosan hydrogels for high sensitivity flexible silk-based electrochemical glucose sensor

Developing enzymatic glucose sensors with high stability and excellent sensing performance is beneficial for the diagnosis and real-time monitoring of diabetes. In this study, we developed an enzymatic glucose sensor with the RGO (Reduced Graphene Oxide) /SF (Silk Fibroin) composite membrane as a flexible and conductive substrate, and then PB (Prussian Blue) was deposited on the surface of RGO/SF. To enhance the stability of GOD (Glucose Oxidase) and enzymatic glucose sensor, enzyme-chitosan hydrogel electropolymerized on the PB/RGO/SF electrode surface and at last a Nafion layer was coated on the hydrogel to prevent hydrogel detachment and mitigate the effects of interferent. This developed GOD/PB/RGO/SF sensor exhibits good sensing performance in glucose detection, with a response time of less than 10 s, a sensitivity as high as 230.96 μA mM−1 cm−2 at low concentration, and a linear range of 65.57 μM–10 mM, and it also shows good anti-interference feature and reproducibility, providing the reliable sensing performance for detecting glucose levels in human organisms and drinks. In conclusion, the GOD/PB/RGO/SF flexible sensor developed in this study has good prospects for application in glucose real-time monitoring and flexible sensing device.

Non-enzymatic glucose sensor using mesoporous carbon screen-printed electrodes modified with cobalt phthalocyanine by phase inversion

The development of non-enzymatic glucose electrochemical sensors is still required to be used for the determination of glucose in complex biological media. This study presents a straightforward and remarkably efficient tool for the preparation of highly stable and sensitive glucose electrochemical sensors based on the deposition of cobalt phthalocyanine (CoPc) onto mesoporous carbon screen-printed electrodes (MCs). Results show that the MC electrochemical activation (aMC) followed by phase inversion (PI), which consisted of drop casting of CoPc in dimethylformamide onto a wetting electrolyte leading to the electrode aMC-CoPc/PI, enhanced sensitivity towards glucose determination in complex media. The beneficial need for MC surface activation and PI has been explored by scanning electron microscopy, energy dispersive X-ray spectroscopy, Raman spectroscopy, cyclic voltammetry and electrochemical impedance spectroscopy. The aMC-CoPc/PI electrode exhibited the highest electrocatalytic activity of the series (namely, MC-CoPc, MC-CoPc/PI and aMC-CoPc) towards glucose oxidation. By using square wave voltammetry technique, the aMC-CoPc/PI glucose electrochemical sensor demonstrated a sensitivity of 22.3 µA mM−1 and a low detection limit of 27.4 µM (S/N = 3) in a linear dynamic range of 0.1 to 3.5 mM. Additionally, it also displayed high selectivity, robust stability, repeatability and reproducibility toward the quantification of glucose concentration in complex samples such as horse serum, intravenous glucose saline solution and culture medium for sperm cells.

Synergistically enhancing electrocatalysis and non-enzymatic sensing for glucose by iridium single-atom/nickel oxide/N-doped graphene.

The development of novel catalyst with high catalytic activity is important for electrochemical non-enzymatic glucose sensing. Here, iridium single-atom/nickel oxide nanoparticle/N-doped graphene nanosheet (Ir1/NiO/NG) with the loading of 1.13 wt% Ir was successfully synthesized for constructing electrochemical non-enzymatic glucose sensor for the first time. The morphology and structure of Ir1/NiO/NG were characterized by XRD, SEM, TEM, HRTEM, and XPS, and the presence of Ir SAs was confirmed by AC-HAADF-STEM. The Ir1/NiO/NG shows 65 mV lower oxidation potential and 3.3 times higher response current than Ni(OH)2/NG. In addition, Ir1/NiO/NG exhibits high sensitivity (70.09 μA mM-1 cm-2), excellent selectivity, low detection limit (2.00 μM), and great stability (91.53% current remaining after 21 days) for electrochemical non-enzymatic glucose sensing. The outstanding catalytic and sensing performance of Ir1/NiO/NG is mainly attributed to synergistic effect of Ir SAs, NiO nanoparticles, and highly conductive NG, which modulate the electronic and geometric structure of Ir1/NiO/NG. This work shows the promising potential of SACs in electrochemical sensing.

Designing of VCuS@MXene nanocomposite electrode for energy storage device and electrochemical glucose sensor

Designing of VCuS@MXene nanocomposite electrode for energy storage device and electrochemical glucose sensor

Designing of high performance MoS2@VZnS//AC hybrid battery supercapacitor device for the electrochemical energy storage and glucose detection

Due to their high conductive properties and superior specific capacitance, metal sulfides exhibit remarkable electrical conductivity. Transition metal dichalcogenides (TMDs) are regarded ideal options for energy harvesting devices due to their unique 2D arrangement and remarkable electrochemical properties. In this work, the typical exfoliation method (tip sonication method) was used to synthesize the molybdenum disulfide (MoS2). By using the hydrothermal method, the vanadium zinc sulfide is synthesized. The composite was analyzed through SEM, XRD, and XPS techniques to investigate its morphological, structural, and compositional characteristics comprehensively. The MoS2@VZnS electrode achieved a specific capacity (Qs) of 1025 Cg−1 at 3 mVs−1 after being tested in 1 M KOH. In a two-electrode set-up, activated carbon is used as a negative electrode, and MoS2@VZnS is used as a positive electrode for the fabrication of a hybrid supercapacitor. The asymmetric device has demonstrated a Qs of 285.4 Cg−1 at 1.4 Ag−1. The fabricated asymmetric supercapacitor device has manifested an excellent energy density (Ed) of 39.5 Whkg−1 and power density (Pd) of 2462.35 Wkg−1. Furthermore, in the durability test of MoS2@VZnS//AC, it exhibited an impressive capacity retention of 91.32% after enduring 5,000 cycles. Besides this, an investigation was conducted on a glucose electrochemical sensor utilizing MoS2@VZnS, to enhance its performance. The device showed extraordinary performance and considerable sensitivity against glucose, even up to a very high value. The multifunctional MoS2@VZnS nanocomposite electrode material provides new opportunities to design hybrid devices in energy storage devices and biomedical applications.