Application For Glucose Biosensing Research Articles

Facile hydrothermal synthesis of NiO/rGO nanocomposite electrodes for supercapacitor and nonenzymatic glucose biosensing application

Facile hydrothermal synthesis of NiO/rGO nanocomposite electrodes for supercapacitor and nonenzymatic glucose biosensing application

Ti3C2Tx MXene as Electrocatalyst for Designing Robust Glucose Biosensors

Abstract2D transition metal carbides, nitrides, and carbo‐nitrides, known as MXenes, have emerged as a versatile class of nanomaterials. MXenes are hailed as remedies to a plethora of global problems. Some of the remarkable ideal properties of MXenes that can transcend the boundaries of current technology, particularly in the field of sensors, include metal‐like high electrical conductivity, quantum confinement effects, electro‐optic properties, large surface area, ease of functionalization, and surface modifications. This review highlights current breakthroughs in fundamental knowledge, synthesis, and attributes of MXene‐based materials for glucose biosensing applications. The effects of various secondary inorganic and organic compounds, such as polymers, carbonaceous materials, transition metal oxides, and metallic nanoparticles on the biosensing performance of the MXenes, analyzed through electrochemical, optical, and noninvasive techniques, toward glucose have been investigated and reviewed. The primary purpose of this review article is thus to give an up‐to‐date critical analysis of MXene composite‐based glucose biosensors, as well as recent achievements and challenges in the synthesis, fabrication of related devices, and novel biosensing approaches. Lastly, the current research challenges and future research potential for MXenes in electrochemical glucose sensing are also addressed.

Utilization of polyvinyl amine hydrolysis product in enhancing the catalytic properties of Co3O4 nanowires: toward potentiometric glucose bio-sensing application

In this study, we used the concept of overnight hydrolysis of polyvinyl amine to grow cobalt oxide (Co3O4) nanostructures with enhanced catalytic properties. The controlled synthesis of Co3O4 nanostructures was carried out with the hydrothermal method using hydrolyzed products. Results showed that the hydrocarbon chain and amide groups produced during the growth process have a great impact on both the morphology and catalytic properties of Co3O4 nanostructures. In fact, the hydrolyzed products supported the growth of nanostructures with a well-defined almost one-dimensional (1-D) morphology of Co3O4 nanowires with a high surface/volume ratio. The as-prepared nanowires were loaded with a high amount of glucose oxidase in order to make them sensitive to glucose and observe a potentiometric response in its presence. The performance of the fabricated biosensor was evaluated in terms of different analytical parameters such as linear range, stability, reproducibility, repeatability, life time, selectivity, and response time. Thus, the obtained Co3O4-based glucose biosensor exhibited a linear response over the concentration range from 0.0005 to 6 mM, with a limit of detection of 0.0001 mM. The estimated Nernstian slope for the glucose biosensor was 42 mV/dec, with stability that exceeds four weeks. Using electrochemical impedance spectroscopy, the Co3O4 nanowires showed a low charge transfer resistance of 2.2 × 103 Ohms. Practically, the biosensor was used successfully to measure the glucose concentration in real blood samples. The results obtained confirm that the proposed glucose biosensor can be used as an alternative tool for monitoring glucose levels. The synthesis procedure described herein has a high potential to produce nanostructured materials on a large scale with well-defined morphology and improved catalytic properties for possible applications in batteries, supercapacitors, and water splitting.

Utilization of FAD-Glucose Dehydrogenase from T. emersonii for Amperometric Biosensing and Biofuel Cell Devices.

Flavin-dependent glucose dehydrogenases (FAD-GDH) are oxygen-independent enzymes with high potential to be used as biocatalysts in glucose biosensing applications. Here, we present the construction of an amperometric biosensor and a biofuel cell device, which are based on a thermophilic variant of the enzyme originated from Talaromyces emersonii. The enzyme overexpression in Escherichia coli and its isolation and performance in terms of maximal bioelectrocatalytic currents were evaluated. We examined the biosensor’s bioelectrocatalytic activity in 2,6-dichlorophenolindophenol-, thionine-, and dichloro-naphthoquinone-mediated electron transfer configurations or in a direct electron transfer one. We showed a negligible interference effect and good stability for at least 20 h for the dichloro-naphthoquinone configuration. The constructed biosensor was also tested in interstitial fluid-like solutions to show high bioelectrocatalytic current responses. The bioanode was coupled with a bilirubin oxidase-based biocathode to generate 270 μW/cm2 in a biofuel cell device.

Hydrothermally synthesized urchinlike NiO nanostructures for supercapacitor and nonenzymatic glucose biosensing application

Nickel oxide nanostructures with different reaction temperatures were synthesized by the hydrothermal method. The formation of NiO nanostructures confirmed by XRD and FTIR analysis. The urchinlike morphology was confirmed from the FE-SEM analysis. The electrochemical supercapacitive properties are studied by EIS, CV and GCD studies. The electrochemical supercapacitor study confirms that the electrode prepared on flexible copper foil by using urchinlike NiO nanostructure with reaction temperature 150 °C shows maximum specific capacitance of 341.10 F g−1 at 10 mV s−1 scan rate. Also, it offers better capacity retention about 96.3% after 1000 cycles. The NiO nanostructures with reaction temperature 110 °C show glucose sensitivity of 878.6 μA mM−1 cm−2 with LOD 0.37 μM.

Sensitivity Analyses of Cu/Chitosan and Ag/Chitosan Based SPR Biosensor for Glucose Detection

This study investigates the sensitivity performance between hybrid thin films of Copper (Cu)/Chitosan and silver (Ag)/Chitosan for glucose biosensing applications. Ag and Cu with refractive indices of n=0.1351+3.9853k and n=0.2388+3.4156k are coated onto the flat surface of hemispherical prism prior 10nm thickness of chitosan (n=1.54+0.015k). The thicknesses of metal are varied between 35nm until 49nm. To generate SPR, a red laser of 633nm p-polarized light is incident onto the Cu/Chitosan and Ag/Chitosan coated prism. Light incident angles are varied from 40° to 60° via the angular interrogation technique. Glucose solution with a concentration of 70mg/dl and 235mg/dl (1.38 RIU and 1.53 RIU, respectively) are flown along with the flow cell during SPR to investigate the sensing ability of the proposed sensors. The relationship between hybrid thin film thicknesses and the value of minimum reflectance shows a polynomial pattern as the thicknesses increased. Based on Q2 analysis, the deployment of Ag/Chitosan results in 18.51% poorer stability performance of Rmin value than Cu/Chitosan SPR sensor. The Cu/Chitosan SPR sensor at total thicknesses within the range from 46nm to 49nm and from 53nm to 56nm exhibits 67% better potential than Ag/Chitosan due to its sensitivity and selectivity in differentiating dissimilar concentration of glucose with a maximum sensitivity of 6°/RIU. We believe the utilization of Cu/Chitosan as plasmonic sensing material offers a low-cost sensor that easy to handle, cheap, miniaturized and excellent sensitivity.

A Molecular Interaction Analysis Reveals the Possible Roles of Graphene Oxide in a Glucose Biosensor.

In this paper, we report the molecular docking study of graphene oxide and glucose oxidase (GOx) enzyme for a potential glucose biosensing application. The large surface area and good electrical properties have made graphene oxide as one of the best candidates for an enzyme immobilizer and transducer in the biosensing system. Our molecular docking results revealed that graphene oxide plays a role as a GOx enzyme immobilizer in the glucose biosensor system since it can spontaneously bind with GOx at specific regions separated from the active sites of glucose and not interfering or blocking the glucose sensing by GOx in an enzyme-assisted biosensor system. The strongest binding affinity of GOx-graphene oxide interaction is −11.6 kCal/mol and dominated by hydrophobic interaction. Other modes of interactions with a lower binding affinity have shown the existence of some hydrogen bonds (H-bonds). A possibility of direct sensing (interaction) model of glucose by graphene oxide (non-enzymatic sensing mechanism) was also studied in this paper, and showed a possible direct glucose sensing by graphene oxide through the H-bond interaction, even though with a much lower binding affinity of −4.2 kCal/mol. It was also found that in a direct glucose sensing mechanism, the sensing interaction can take place anywhere on the graphene oxide surface with almost similar binding affinity.

Influence of LiClO4 Concentration on 1-D Polypyrrole Nanofibers for Enhanced Performance of Glucose Biosensor

In the present work, a template-free single-step fabrication of Lithium perchlorate (LiClO4) doped 1-D Polypyrrole nanofibers network (PNN) (without using electrospinning) toward glucose biosensing application has been reported. The PNN with different concentrations of LiClO4 was grown over the Platinum coated glass substrate by electropolymerization method and utilized as a support matrix for immobilization of enzyme. The effect of LiClO4 concentration on glucose biosensor performance has been demonstrated for the first time. The modification in morphology and reduction in charge transfer resistance of PNNs by varying LiClO4 concentration were found to play a significant role in the improved figure of merits of the biosensor. Among all the types of as-fabricated PNN electrodes (prepared by using different concentrations of LiClO4 viz. 1, 10, 50, and 70 mM) the best response was obtained corresponding to highest LiClO4 concentration. The enzyme loading and charge transfer resistance were drastically improved by approximately three folds owing to the higher surface area and improved conductivity of PNN electrodes thereby resulting in ten-fold increment in sensitivity. The as-prepared biosensor showed the highest sensitivity of 4.34 mA-cm−2-M−1 and a linear range of 0.1–4.6 mM with good stability and high selectivity for glucose detection.

Influence of aspect ratio and surface defect density on hydrothermally grown ZnO nanorods towards amperometric glucose biosensing applications

In this work, hydrothermally grown ZnO Nanorods Array (ZNA) has been synthesized over Platinum (Pt) coated glass substrate, for biosensing applications. In-situ addition of strong oxidizing agent viz KMnO4 during hydrothermal growth was found to have profound effect on the physical properties of ZNA. Glucose oxidase (GOx) was later immobilized over ZNA by means of physical adsorption process. Further influence of varying aspect ratio, enzyme loading and surface defects on amperometric glucose biosensor has been analyzed. Significant variation in biosensor performance was observed by varying the amount of KMnO4 addition during the growth. Moreover, investigations revealed that the suppression of surface defects and aspect ratio variation of the ZNA played key role towards the observed improvement in the biosensor performance, thereby significantly affecting the sensitivity and response time of the fabricated biosensor. Among different biosensors fabricated having varied aspect ratio and surface defect density of ZNA, the best electrode resulted into sensitivity and response time to be 18.7mAcm−2M−1 and <5s respectively. The observed results revealed that apart from high aspect ratio nanostructures and the extent of enzyme loading, surface defect density also hold a key towards ZnO nanostructures based bio-sensing applications.

Electrochemical glucose biosensing via new generation DTP type conducting polymers/gold nanoparticles/glucose oxidase modified electrodes

The synthesis of derivatives of dithionepyrrole is a hot subject that has been studied extensively. In this study, a novel approach for constructing different glucose biosensors using conducting polymers of 4-(4H-dithyinol[3,2-b:2′,3′-d]pyroll-4-yl)aniline and 4-(4H-dithyinol[3,2-b:2′,3′-d]pyroll-4-yl)-[1,1′-biphenyl]-4-amine is proposed. After the synthesis and characterizations of the dithionepyrrole type monomers, they were used in glucose biosensing applications. The surface of gold electrode was modified with mercaptoethane sulfonic acid and p-aminothiophenol functionalized gold nanoparticles and aniline modified GOx. Electrochemical measurements were carried out by following the consumed oxygen due to the enzymatic reaction of glucose oxidase. DTP-Ph-NH2/AuNP/GOx and DTP-Ph-Ph-NH2/AuNP/GOx biosensors showed very good linearity between 0.1 and 2.5mM, and 0.05 and 1mM for glucose, respectively. LOD value was obtained for pDTP-Ph-NH2/AuNP/GOx as 5.00×10−2mM and for pDTP-Ph-Ph-NH2/AuNP/GOx as 9.86×10−5mM using S/N ratio. Optimization of molar ratio amount of AuNP/GOx, cycles amount to immobilize AuNP/GOx, conducting polymer thickness were examined. Finally, under optimized conditions, the amount of glucose in spiked human serum samples and recovery experiments were conducted.

Self-assembled NiFe2O4/carbon nanotubes sponge for enhanced glucose biosensing application

In this work, self-assembled NiFe2O4/carbon nanotubes (CNTs) sponge was prepared by ice-templating method. The device synergized the advantageous features of both the 3D porous nanostructure and the catalytic properties of CNTs with GOx and NiFe2O4 nanoparticles. The porous network construction of the NiFe2O4/CNTs sheets offered enlarged specific surface for GOx immobilization and opened channels for facilitating the electrons transport and reactants diffusion. With the help of the abnormal-valence elements Ni and Fe, double catalysis has happened and the enhanced glucose biosensing performance has been achieved. The fabricated glucose biosensor exhibited two large linear ranges (0–3.0 and 3.2–12.4mM) and distinct sensitivities (84.1 and 24.6μAmM−1cm−2).

Direct Electrochemistry of Glucose Oxidase at Reduced Graphene Oxide and β‐Cyclodextrin Composite Modified Electrode and Application for Glucose Biosensing

AbstractA simple glucose biosensor has been developed based on direct electrochemistry of glucose oxidase (GOx) immobilized on the reduced graphene oxide (RGO) and β‐cyclodextrin (CD) composite. A well‐defined redox couple of GOx appears with a formal potential of ∼−0.459 V at RGO/CD composite. A heterogeneous electron transfer rate constant (Ks) has been calculated for GOx at RGO/CD as 3.8 s−1. The fabricated biosensor displays a wide response to glucose in the linear concentrations range from 50 µM to 3.0 mM. The sensitivity and limit of detection of the biosensor is estimated as 59.74 µA mM−1 cm−2 and 12 µM, respectively.

Development of Low Cost Rapid Fabrication of Sharp Polymer Microneedles for In Vivo Glucose Biosensing Applications

New approaches to enable more effective management of diabetes mellitus, such as continuous glucose monitoring are being developed both to prevent unstable episodes of hypo or hyper glycaemia and also to provide an improved user experience. One emerging approach to realize these requirements is to fabricate a minimally invasive transdermal sensor for the direct in vivo detection of glucose in the interstitial fluid. Microneedles – sharp, microscopic structures measuring less than 1 mm in length – have been previously employed to allow painless penetration of the stratum corneum for delivery of drugs and vaccines. In this work we present, ultra sharp gold coated polymer microneedle arrays (sub micron tip radii) which are fabricated using a low cost polymer replication approach. Critical dimensions of the microneedle arrays are characterized using a combination of optical and scanning electron microscopies. Fabricated microneedle devices are characterized by cyclic voltammetry to explore functionality. The voltammetric detection of glucose is performed using ferrocene monocarboxylic acid as an oxidising mediator in the presence of glucose oxidase. The biosensor can be applied to the quantification of glucose in the physiological range (2 – 13.5 mM). The sensors demonstrate high selectivity towards glucose with negligible interference from other oxidizable species including uric acid, ascorbic acid, mannose, fructose, salicylic acid (Aspirin) and acetaminophen (Paracetamol). This demonstrates potential future use of these microneedle devices for in vivo glucose detection.

Electrochemical Performance of Electrospun Free-Standing Nitrogen-Doped Carbon Nanofibers and Their Application for Glucose Biosensing

In spite of excellent electrochemical properties, nitrogen-doped carbon nanofibers (NCNFs) have rarely been studied in the field of electroanalysis. In this work, we investigated the electrochemical properties and biosensing performance of NCNFs prepared by a newly proposed approach. The as-obtained NCNFs present a unique free-standing structure with high flexibility which could be convenient for electrode modification. Electrochemical measurements of typical redox species including [Ru(NH3)6]3+/2+, [Fe(CN)6]3-/4-, [Fe(H2O)6]3+/2+, and dopamine indicate that the NCNFs have a larger surface area and faster electron transfer rate compared with carbon nanofibers (CNFs). The presence of high content of pyrrolic-N and abundant defective sites in NCNFs leads to an obvious positive shift of peak potential for oxygen reduction at NCNFs relative to that obtained at CNFs. The unique structure and properties greatly enhance the electrochemical performance of NCNFs. The glucose biosensor based on glucose oxidase/NCNFs shows linear ranges of 0.2-1.2 mM at -0.42 V and 0.05-3 mM at 0.40 V both with high stability. These results suggest that the NCNFs could be a convenient and stable platform for electrochemical biosensors.

Monodispersed silica nanoparticles as carrier for co-immobilization of bi-enzyme and its application for glucose biosensing

A novel glucose sensing strategy by using bi-enzyme coated monodispered silica nanoparticles (SiO2) was proposed. The monodispered SiO2 was synthesized according to our previously reported seed-growth methods. Glucose oxidase (GOD) and horseradish peroxidase (HRP) were simultaneously covalent immobilized on the surface of SiO2 nanoparticles through the cross-linker of glutaraldehyde. The immobilized bi-enzyme remained their bioactivities well for the substrate reaction. Thus, the resultant SiO2-GOD/HRP nanocomposites could be used as catalyst for enzymatic substrate reactions in the presence of 3,3′,5,5′-tetramethylbenzidine (TMB) as chromogenic reagent and glucose as substrate. The factors of affecting the catalytic activities of enzymes were optimized. Under optimal conditions, the absorbance at 450nm in UV–visible spectra increased with the glucose concentration, which could be used for glucose detection with a linear range from 0.5μM to 250μM and a detection limit of 0.22μM at a signal-to-noise ratio of 3σ. Considering the potential of making pills using this SiO2-GOD/HRP, the present strategy has good prospect in the clinic science and other fields in future.

Pure copper vs. mixed copper and palladium hexacyanoferrates for glucose biosensing applications

A glucose amperometric biosensor was developed. Glucose oxidase enzyme was immobilized by means of a Nafion membrane on glassy carbon modified with an electrochemically deposited mixed Cu and Pd hexacyanoferrate (CuPdHCF). According to the data provided by X-ray atomic spectroscopy measurements, this Cu- and Pd-based hexacyanoferrate is likely to be a mixture of single CuHCF and PdHCF pure phases. The biosensor performances were evaluated by recording the steady-state currents due to submillimolar additions of glucose to a potassium buffer solution (pH 5.5) and exploiting the electrocatalytic reduction of the enzymatically produced hydrogen peroxide. The CuPdHCF-based biosensor exhibited a sensitivity of 8.1 ± 0.6 A M−1 m−2, a limit of detection of 1.4 × 10−5 M, and a linear response range extending between 5 × 10−5 and 4 × 10−4 M, with a dynamic response range up to 4 × 10−3 M glucose. Electrode sensitivity and signal stability resulted more satisfactory as compared to those of a CuHCF-based biosensor fabricated according to the same procedure. The selectivity was investigated through an interference study. The response to easily oxidizable species was found to be low enough to allow glucose determination in biological samples.

Direct Electrochemistry of Glucose Oxidase on Graphene-ZnO Nanocomposite Modified Glassy Electrode and Its Application for Glucose Biosensing

Graphene was coated on glassy carbon electrode and ZnO was then electrodeposited on the modified electrode.The biosensor was fabricated for sensitive determination of glucose after glucose oxidase was immobilized on the modified electrode.Scanning electron microscope was used to characterize the nano-composite film.The electrochemical behaviors of glucose oxidase on the modified electrode were investigated in the range of -0.7 V to -0.1 V by cyclic voltammetry.The experimental results demonstrated that the nanocomposite well retained the activity of glucose oxidase and the biosensor exhibited excellent electrocatalytic activity toward the redox of glucose.In 0.1 mol/L PBS(pH 7.0),the glucose oxidase adsorbed onto the graphene/ZnO composite film exhibits a pair of well-defined nearly reversible redox peaks and fine catalysis to the oxidation of glucose.The electron transfer rate constant(ks) of glucose oxidase at the modified electrode was 1.42 s-1,and Michaelis-Menten constant(Kappm) was 14.2 μmol/L.A good linear relationship was obtained in the range of 2.5×10-6 –1.5×10-3 mol/L,with the limits of detection of 2.4×10-7 mol/L(S/N=3).The biosensor has good conductivity,stability and repeatability,and it can be used to analyze real samples.

Ultrathin graphitic carbon nitride nanosheets: a low-cost, green, and highly efficient electrocatalyst toward the reduction of hydrogen peroxide and its glucose biosensing application

In this communication, we demonstrate for the first time that ultrathin graphitic carbon nitride (g-C₃N₄) nanosheets can serve as a low-cost, green, and highly efficient electrocatalyst toward the reduction of hydrogen peroxide. We further demonstrate its application for electrochemical glucose biosensing in both buffer solution and human serum medium with a detection limit of 11 μM and 45 μM, respectively.

Graphene bridged enzyme electrodes for glucose biosensing application

The fabrication of glucose oxidase (GOx) enzyme electrodes with controlled alternate enzyme and graphene layers is described. GOx was first modified with pyrene functionalities in order to be self-assembled onto a graphene basal plane via non-covalent π-π stacking interaction. Fluorescence spectroscopy analysis revealed that about 5.4 pyrene functional groups were attached to each GOx and the pyrene functionalized GOx retained more than 76% of the biocatalytical activity compared with the native enzyme. Via alternate layer-by-layer self-assembly of graphene and pyrene functionalized GOx, mono- and multi-layered enzyme electrodes with controlled biocatalytical activity can be easily fabricated. The biocatalytical activity of the as-prepared enzyme electrodes increased with increasing graphene and GOx layers and increased insignificantly when the layers reached four. Such multi-layered enzyme electrodes with controlled nanostructure exhibited reliable application in human serum samples analysis with high detection sensitivity, good stability and repeatability. A broad linear detection limit of 0.2 to 40 mM was obtained.

Controllable growth of Prussian blue nanostructures on carboxylic group-functionalized carbon nanofibers and its application for glucose biosensing

Glucose detection is very important in biological analysis, clinical diagnosis and the food industry, and especially for the routine monitoring of diabetes. This work presents an electrochemical approach to the detection of glucose based on Prussian blue (PB) nanostructures/carboxylic group-functionalized carbon nanofiber (FCNF) nanocomposites. The hybrid nanocomposites were constructed by growing PB onto the FCNFs. The obtained PB–FCNF nanocomposites were characterized by scanning electron microscopy, x-ray diffraction and x-ray photoelectron spectroscopy. The mechanism of formation of PB–FCNF nanocomposites was investigated and is discussed in detail. The PB–FCNF modified glassy carbon electrode (PB–FCNF/GCE) shows good electrocatalysis toward the reduction of H2O2, a product from the reduction of O2 followed by glucose oxidase (GOD) catalysis of the oxidation of glucose to gluconic acid. Further immobilizing GOD on the PB–FCNF/GCE, an amperometric glucose biosensor was achieved by monitoring the generated H2O2 under a relatively negative potential. The resulting glucose biosensor exhibited a rapid response of 5 s, a low detection limit of 0.5 μM, a wide linear range of 0.02–12 mM, a high sensitivity of 35.94 μA cm−2 mM−1, as well as good stability, repeatability and selectivity. The sensor might be promising for practical application.