Electrochemical Glucose Sensor Research Articles

Towards the Integration of an Islet-Based Biosensor in Closed-Loop Therapies for Patients With Type 1 Diabetes

In diabetes mellitus (DM) treatment, Continuous Glucose Monitoring (CGM) linked with insulin delivery becomes the main strategy to improve therapeutic outcomes and quality of patients’ lives. However, Blood Glucose (BG) regulation with CGM is still hampered by limitations of algorithms and glucose sensors. Regarding sensor technology, current electrochemical glucose sensors do not capture the full spectrum of other physiological signals, i.e., lipids, amino acids or hormones, relaying the general body status. Regarding algorithms, variability between and within patients remains the main challenge for optimal BG regulation in closed-loop therapies. This work highlights the simulation benefits to test new sensing and control paradigms which address the previous shortcomings for Type 1 Diabetes (T1D) closed-loop therapies. The UVA/Padova T1DM Simulator is the core element here, which is a computer model of the human metabolic system based on glucose-insulin dynamics in T1D patients. That simulator is approved by the US Food and Drug Administration (FDA) as an alternative for pre-clinical testing of new devices and closed-loop algorithms. To overcome the limitation of standard glucose sensors, the concept of an islet-based biosensor, which could integrate multiple physiological signals through electrical activity measurement, is assessed here in a closed-loop insulin therapy. This investigation has been addressed by an interdisciplinary consortium, from endocrinology to biology, electrophysiology, bio-electronics and control theory. In parallel to the development of an islet-based closed-loop, it also investigates the benefits of robust control theory against the natural variability within a patient population. Using 4 meal scenarios, numerous simulation campaigns were conducted. The analysis of their results then introduces a discussion on the potential benefits of an Artificial Pancreas (AP) system associating the islet-based biosensor with robust algorithms.

Reusable electrochemical non-enzymatic glucose sensors based on Au-inlaid nanocages

Reusable electrochemical non-enzymatic glucose sensors based on Au-inlaid nanocages

Turning coordination environment of 2D nickel-based metal-organic frameworks by π-conjugated molecule for enhancing glucose electrochemical sensor performance

The design and synthesis of the high-efficiency electrochemical sensor is the key to electrochemical conversion technology. This work synthesized Ni-based metal-organic framework (Ni-MOF) nanosheets by a competitive double ligands hybridization strategy. They were used as precursors to construct Ni-MOF@Ni-2,3,6,7,10,11-hexahydroxytriphenylene (HHTP) core@shell structures by introducing π - conjugated molecule, HHTP. EXAFS further confirmed the interaction between Ni atoms and hexahydroxytriphenylene molecules. This process helps to promote more exposure of its active sites and enhance its electrochemical performance to become a high-performance enzyme glucose sensor. After coating, glucose detection sensitivity increased from 139.82 to 2124.90 μA/(mM cm2). These findings lay the foundation for preparing two-dimension hybrid functional MOF materials.

Prussian Blue-Based Flexible Thin Film Nanoarchitectonics for Non-enzymatic Electrochemical Glucose Sensor

Prussian Blue-Based Flexible Thin Film Nanoarchitectonics for Non-enzymatic Electrochemical Glucose Sensor

MXene nanoflakes decorating ZnO tetrapods for enhanced performance of skin-attachable stretchable enzymatic electrochemical glucose sensor

Continuous painless glucose monitoring is the greatest desire of more than 422 million diabetics worldwide. Therefore, new non-invasive and convenient approaches to glucose monitoring are more in demand than other tests for microanalytical diagnostic tools. Besides, blood glucose detection can be replaced by continuous glucose monitoring of other human biological fluids (e.g. sweat) collected non-invasively. In this study, a skin-attachable and stretchable electrochemical enzymatic sensor based on ZnO tetrapods (TPs) and a new class of 2D materials - transition metal carbides, known as MXene, was developed and their electroanalytical behavior was tailored for continuous detection glucose in sweat. The high specific area of ZnO TPs and superior electrical conductivity of MXene (Ti3C2Tx) nanoflakes enabled to produce enzymatic electrochemical glucose biosensor with enhanced sensitivity in sweat sample (29 μA mM−1 cm−2), low limit of detection (LOD ≈ 17 μM), broad linear detection range (LDR = 0.05–0.7 mM) that satisfices glucose detection application in human sweat, and advanced mechanical stability (up to 30% stretching) of the template. The developed skin-attachable stretchable electrochemical electrodes allowed to monitor the level of glucose in sweat while sugar uptake and during physical activity. Continuous in vivo monitoring of glucose in sweat obtained during 60 min correlated well with data collected by a conventional amperometric blood glucometer in vitro mode. Our findings demonstrate the high potential of developed ZnO/MXene skin-attachable stretchable sensors for biomedical applications on a daily basis.

Chitosan polymer matrix-derived nanocomposite (CuS/NSC) for non-enzymatic electrochemical glucose sensor

In this study, N and S co-doped chitosan polymer matrix-derived composite (CuS/NSC) was synthesized via a one-step hydrothermal technique using a low-cost copper complex of chitosan polymer. Cyclic voltammetry and chronoamperometry revealed excellent electrocatalytic performance. The glucose sensor exhibited a linear range of 160 μM to 11.76 mM, a low detection limit 2.72 μM and a sensitivity of 13.62 mA mM−1 cm−2 with an excellent linear response. Furthermore, the sensor also displayed selectivity for glucose over potential interfering agents and exhibited a satisfactory recovery percentage using real sample in human serum. The results demonstrate that, CuS/NSC is an efficient nanocomposite material for non-enzymatic glucose sensors and is applicable for glucose detection in biological fluids.

A novel flexible non-enzymatic electrochemical glucose sensor of excellent performance with ZnO nanorods modified on stainless steel wire sieve and stimulated via UV irradiation

A novel flexible non-enzymatic electrochemical glucose sensor was constructed with hexagonal structured ZnO nanorods hydrothermally grown on bendable stainless steel wire sieve (SSWS) electrode. The electrocatalytic capability of the sensor towards glucose was obviously enhanced with ultraviolet (UV) irradiation introduced during the electrochemical measurements. To be specific, UV irradiation promotes the generation of holes in the ZnO nanorods and these holes raise the amount of hydroxyl. Accordingly, more hydroxyl reacts with glucose and further the electron yield of the glucose sensor is notably increased, thus the sensitivity of the glucose sensor is raised from 36.4 μA mM−1 cm−2 to 91.8 μA mM−1 cm−2. The glucose sensor can maintain 60% and 90% of the initial current after being bended 100 times and used 20 times, respectively. Besides, the glucose sensor also exhibits ignorable response towards interfering substances like d-galactose, fructose, urea, uric acid, ascorbic acid, l-phenylalanine, NaCl, and KCl, and can reliably determine glucose concentrations in human serum samples. This method is considered as an effective way to enhance the electrocatalytic capability of other semiconductor-based electrochemical biosensors.

Cobalt single atom sites in carbon aerogels for ultrasensitive enzyme-free electrochemical detection of glucose

• Carbon aerogels with atomically dispersed cobalt by pyrolysis of hydrogel precursor. • CoN x moieties at nanopore edges show preferred adsorption of glucose. • Electrocatalytic activity of CoN x towards glucose oxidation. • Excellent detection of glucose in artificial saliva and human serum samples. Enzyme-free electrochemical glucose sensors have been attracting extensive attention, due to high sensitivity, excellent stability, and low cost, as compared to the conventional counterparts based on biological enzymes such as glucose oxidase. Within this context, development of low-cost, high-performance electrode catalysts represents a critical first step, and nanocomposites with atomically dispersed metal sites have emerged as viable candidates. In this study, nitrogen-doped carbon aerogel (NCA) embedded with CoN x sites is derived pyrolytically from biomass hydrogels and serves as an electrode catalyst for the detection of glucose. The three-dimensional porous skeletons of NCA help disperse the Co single atom sites and facilitate the mass transfer during electrochemical reaction. Theoretical calculations reveal that the single metal sites (CoN 3 and CoN 4 ) at the edge of nanopores show optimal adsorption towards glucose, and likely make a dominant contribution to the high activity in glucose detection. In electrochemical measurements, the NCA-Co based, enzyme-free glucose sensor shows a detection limit of 0.1 μM, with a wide linear range from 0.5 μM to 6 mM, good stability, high selectivity and excellent reproducibility. Notably, this sensing platform also exhibits an excellent performance in determining the glucose contents in artificial saliva and human serum samples, indicating great potential for practical applications.

Blood glucose sensors and recent advances: A review

Blood glucose (BG) concentration of the human body serves as an important index for diagnosis of diabetes, and its detection methods need to be more efficient due to high mortality rates for diabetes. Typical household BG meters are invasive products based on electrochemistry and rely on finger pricks to procure blood, which might result in skin damage and bacterial infections. Moreover, such BG meters can only detect the BG concentration at a certain time while ignoring the BG level at other times. Recently, to achieve microinvasive, noninvasive and continuous glucose monitoring (CGM) by detecting body fluid, such as sweat or tears, the research direction has been gradually developing toward wearable devices. This review discusses the glucose detection mechanism of various electrochemical and optical glucose sensors, and briefly analyzes their advantages and challenges. Additionally, wearable products based on various principles that have appeared on the market are also summarized. Furthermore, based on the analysis, this review proposes a design concept for future research directions.

Laser-scribed graphene sensors on nail polish with tunable composition for electrochemical detection of nitrite and glucose

Laser-induced graphene (LIG) techniques enable the direct laser writing or scribing of conductive graphene electrodes on insulative polymer substrates without complicated synthesis or fabrication processes. The precursors of LIG essentially determine its quality and applications in various fields including electrochemical devices. Here, we demonstrate that the widely used nail polish (NP) is a promising precursor of LIG, which can be converted into 3D porous graphene electrodes in air using a 405 nm laser engraving machine. The produced nail polish-based LIG (NP-LIG) electrodes possess high conductivity, good mechanical property, and tunable composition and electrochemical activity. These unique properties make NP-LIG a promising platform for developing cost-effective electrochemical sensing devices. A robust flexible electrochemical sensor of nitrite was therefore constructed on NP-LIG using chitosan as a sensing material, which shows a sensitive and selective response for the detection of nitrite with a calibration range of 2.0–1000 μM and a detection limit of 0.9 μM (S/N = 3). In addition, a non-enzymatic glucose electrochemical sensor was constructed by doping NP-LIG with copper ions (Cu2+/NP-LIG), suggesting the doping ability of NP-LIG by a simple mixing method.

Cost Effective Synthesis of Graphene Nanomaterials for Non-Enzymatic Electrochemical Sensors for Glucose: A Comprehensive Review.

The high conductivity of graphene material (or its derivatives) and its very large surface area enhance the direct electron transfer, improving non-enzymatic electrochemical sensors sensitivity and its other characteristics. The offered large pores facilitate analyte transport enabling glucose detection even at very low concentration values. In the current review paper we classified the enzymeless graphene-based glucose electrocatalysts’ synthesis methods that have been followed into the last few years into four main categories: (i) direct growth of graphene (or oxides) on metallic substrates, (ii) in-situ growth of metallic nanoparticles into graphene (or oxides) matrix, (iii) laser-induced graphene electrodes and (iv) polymer functionalized graphene (or oxides) electrodes. The increment of the specific surface area and the high degree reduction of the electrode internal resistance were recognized as their common targets. Analyzing glucose electrooxidation mechanism over Cu- Co- and Ni-(oxide)/graphene (or derivative) electrocatalysts, we deduced that glucose electrochemical sensing properties, such as sensitivity, detection limit and linear detection limit, totally depend on the route of the mass and charge transport between metal(II)/metal(III); and so both (specific area and internal resistance) should have the optimum values.

Single-Atom Pt Boosting Electrochemical Nonenzymatic Glucose Sensing on Ni(OH)2/N-Doped Graphene.

Conventional nanomaterials in electrochemical nonenzymatic sensing face huge challenge due to their complex size-, surface-, and composition-dependent catalytic properties and low active site density. In this work, we designed a single-atom Pt supported on Ni(OH)2 nanoplates/nitrogen-doped graphene (Pt1/Ni(OH)2/NG) as the first example for constructing a single-atom catalyst based electrochemical nonenzymatic glucose sensor. The resulting Pt1/Ni(OH)2/NG exhibited a low anode peak potential of 0.48 V and high sensitivity of 220.75 μA mM-1 cm-2 toward glucose, which are 45 mV lower and 12 times higher than those of Ni(OH)2, respectively. The catalyst also showed excellent selectivity for several important interferences, short response time of 4.6 s, and high stability over 4 weeks. Experimental and density functional theory (DFT) calculated results reveal that the improved performance of Pt1/Ni(OH)2/NG could be attributed to stronger binding strength of glucose on single-atom Pt active centers and their surrounding Ni atoms, combined with fast electron transfer ability by the adding of the highly conductive NG. This research sheds light on the applications of SACs in the field of electrochemical nonenzymatic sensing.

Advances in the Use of Graphene Nanocomposites for the Electrochemical Determination of Glucose: A Review

Background: Glucose detection is of great significance in biomedicine. In clinical medicine, diabetes seriously endangers human health. By accurately measuring the blood glucose content of diabetic patients, diabetes can be effectively monitored and treated. At present, there are many methods for measuring glucose content, such as chromatography, spectroscopy, and electrochemical methods. Among them, electrochemical glucose sensors are widely used because of their high reliability, low cost, and easy operation. Methods: Combining graphene with other nanomaterials (including graphene, metal oxides, semiconductor nanoparticles, polymers, dye molecules, ionic liquids and biomolecules) is an effective way to expand or enhance the sensing performance. Results: The composite of graphene and nanomaterials is an effective way to enhance the functionality of the electrochemical sensor. Graphene can accelerate electron transfer and realize direct electrochemistry and biological sensing. At the same time, graphene derivatives with rich composition and structure provide the possibility to further regulate their electrochemical performance. These graphene composite-based biosensors have shown excellent sensitivity and selectivity for glucose detection. Conclusion: Electrochemical glucose sensors based on graphene composite have received extensive attention. Although these materials have made significant progress in improving the sensitivity, lowering the detection limit and broadening the linear range, there are still facing challenges that require further study.

MOF-derived carbon-coated cuprous phosphide nanosheets for electrocatalytic glucose oxidation

A type of carbon-coated cuprous phosphide nanosheet embedded into a MOF-derived porous carbon network (Cu-BTC-CP) presents a competitive electrochemical sensor for practical glucose sensing.

A Novel and Ultra Sensitive Non-Enzymatic Electrochemical Glucose Sensor in Real Human Blood Samples Based on Facile One-Step Electrochemical Synthesis of Nickel Hydroxides Nanoparticles Onto a Three-Dimensional Inconel 625 Foam

A Novel and Ultra Sensitive Non-Enzymatic Electrochemical Glucose Sensor in Real Human Blood Samples Based on Facile One-Step Electrochemical Synthesis of Nickel Hydroxides Nanoparticles Onto a Three-Dimensional Inconel 625 Foam

Copper Nanoparticles/Polyaniline/Molybdenum Disulfide Composite as a Non-Enzymatic Electrochemical Glucose Sensor

Copper Nanoparticles/Polyaniline/Molybdenum Disulfide Composite as a Non-Enzymatic Electrochemical Glucose Sensor

Surface charge modulation enhanced high stability of gold oxidation intermediates for electrochemical glucose sensors.

Rapid and accurate blood glucose detection is significant for diagnosing and treating diabetes. Herein, ultra-low-content gold nanoparticles were loaded on different metal foams and applied to electrochemical enzyme-free glucose sensors via simple displacement reactions. The structures and properties of the produced catalysts were determined by various characterization methods. The performance of the glucose sensor was examined in relation to the interactions between three different metal substrates and gold. The one with the best performance is the sample of gold nanoparticles grown on copper foam (Au300 Cu Foam). It has the advantage of a porous three-dimensional network, a large electroactive surface area, and the high catalytic activity of gold. The combination of Cu and Au increased the valence state of Au, thus favoring the catalytic activity for glucose oxidation. Cyclic voltammetry and chronoamperometry measurements revealed that Au is responsible for the electrocatalytic oxidation of glucose. The sensitivity of Au300 Cu Foam was found to be 10 839 μA mM-1 cm-2 in the linear range of 0.00596-0.0566 mM, with a detection limit (LOD) of 0.223 μM, and 2-3 s response time at 0.4 V vs. Ag/AgCl. The Au300 Cu Foam glucose sensor also offered outstanding stability and anti-interference performance. The prepared Au300 Cu Foam electrode was also successfully applied to detect different levels of glucose in human body fluids, such as saliva. These characteristics make Au300 Cu Foam promising for non-invasive glucose detection.

Bimetal-organic frameworks MnCo-MOF-74 derived Co/MnO@HC for the construction of a novel enzyme-free glucose sensor

An enzyme-free glucose electrochemical sensor was constructed based on MnCo-based nanoparticles with hierarchical carbon (Co/MnO@HC), which was derived from solvothermal synthesis of MnCo-MOF-74. Detailed characteristics of the as-prepared materials were investigated by scanning electron microscope (SEM), X-ray diffraction (XRD), transmission electron microscopy (TEM), high resolution TEM (HRTEM), energy disperse spectroscopy (EDS) mapping and X-photoelectron spectroscopy (XPS). Then Co/MnO@HC was dropped onto glassy carbon electrode (GCE) to fabricate a novel enzyme-free glucose sensor. The performance of the sensor was studied by cyclic voltammetry (CV) and chronoamperometry, the results showed that the biosensor has good electrocatalytic activity for glucose in the range of 50–900 μM and 1.9–6.9 mM with a sensitivity of 233.8 μA mM−1 cm−2 and a detection limit (S/N = 3) of 1.31 μM. Further, the constructed Nafion/Co/MnO@HC/GCE has been successfully applied to determine glucose in real serum samples, which exhibited excellent reproducibility, anti-interference and stability.

Novel electrochemical non-enzymatic glucose sensor based on 3D Au@Pt core–shell nanoparticles decorated graphene oxide/multi-walled carbon nanotubes composite

A novel carbon composite was integrated with Au@Pt core–shell nanoparticles (Au@Pt NPs) to construct a sensing interface for enzyme-free electrochemical detection of glucose. As surfactant, graphene oxide (GO) was used to disperse multi-walled carbon nanotubes (MWCNTs). After the glassy carbon electrode (GCE) was modified with the mixture of GO and MWCNTs, the Au@Pt NPs were decorated on it. The prepared novel three-dimensional sensor interface was applied to detect glucose without enzyme at a remarkable negative potential (at about −0.013 V vs. Ag/AgCl), demonstrating a low detection limit (4.2 × 10−8 M) and two wide linear range from 5 × 10−8 to 1 × 10−4 M and 1 × 10−4 M to 2.5 × 10−3 M. In addition, the non-enzymatic glucose sensing platform can be realized for practical application.

Metal Oxide-Based Composites in Nonenzymatic Electrochemical Glucose Sensors

The new generation of glucose biosensors has gained immense research interest owing to its cost effectiveness, quick response, good stability, reproducibility, and low detection limit. The enzymatic glucose sensor suffers from numerous intrinsic disadvantages; therefore, there is a need to develop a new biosensor which can overcome the disadvantages of enzymatic glucose biosensors. In that context, metal oxide-based nanostructures and their compostites exhibit properties that can overcome the drawbacks of enzymatic glucose sensors. This review discusses recent developments in some of the metal oxides (CoO, NiO, CuO, and ZnO) along with their composites as well as their applications toward nonenzymatic glucose sensors. The metal oxide composites possess excellent features which signify the potential commercial applications of metal oxide-based composites for nonenzymatic electrochemical glucose sensing.