Sensitive Determination Of Glucose Research Articles

Construction of Covalent Organic Framework Capsule-Based Nanoreactor for Sensitive Glucose Detection.

Enzyme immobilization is critical to boosting its application in various areas. Covalent organic frameworks (COFs) are ideal hosts for enzyme immobilization due to their porous and predesignable structures. Nevertheless, the construction of COFs-based enzyme immobilization systems with high activity via existing immobilization methods (including covalent linkages and channel entrapment) remains a considerable challenge. Herein, a versatile approach was introduced to encapsulate enzymes within hollow COF capsule (named enzyme@COF) using metal-organic frameworks (including ZPF-1(C8H11N4O4.5Zn), ZIF-8(C8H10N4Zn), and ZIF-90(C8H6N4O2Zn)) as sacrificial templates. The obtained porous COF capsule could not only facilitate the efficient mass transfer of enzymatic reactions but also protect enzymes against the incompatible conditions, resulting in enhanced activity and stability of the encapsulated enzymes. Moreover, this approach offered an opportunity to spatially organize multienzymes in COF capsule to construct enzyme cascade system. For instance, glucose oxidase (GOx) and cytochrome c (Cyt c) were coencapsulated within COF capsule to construct GOx-Cyt c cascade. The integration of GOx and Cyt c within COF capsule achieved ∼1.6-fold improvement in catalytic activity than that of free enzymes and the resultant GOx-Cyt c@COF was successfully adopted as a nanoreactor for the sensitive determination of glucose in serum. This work provided a new insight into the design of COFs-based enzyme immobilization systems.

Fe(III)-incorporated porphyrin-based conjugated organic polymer as a peroxidase mimic for the sensitive determination of glucose and H2O2.

Nanozymes, i.e., nanomaterials that possess intrinsic enzyme-like behaviour, have thrived over the past few decades owing to their advantages of superior stability and effortless storage. Such artificial enzymes can be a perfect alternative to naturally occurring enzymes, which have disadvantages of high cost and limited functionality. In this work, we present the fabrication of an Fe(III)-incorporated porphyrin-based conjugated organic polymer as a nanozyme for the efficient detection of glucose through its intrinsic peroxidase activity and the amperometric detection of hydrogen peroxide. The iron-incorporated porphyrin-based conjugated organic polymer (Fe-DMP-POR) possesses a spherical morphology with high chemical and thermal stability. Exploiting the peroxidase-mimicking activity of the material for the determination of glucose, a detection limit of 4.84 μM is achieved with a linear range of 0-0.15 mM. The Fe-DMP-POR also exhibits a reasonable recovery range for the detection of human blood glucose. The as-synthesized material can also act as an H2O2 sensor, with a sensitivity of 947.67 μA cm-2 mM-1 and a limit of detection of 3.16 μM.

Gold Nanoparticle (Au NP)-Decorated Ionic Liquid (IL) Based Liposome: A Stable, Biocompatible, and Conductive Biomimetic Platform for the Fabrication of an Enzymatic Electrochemical Glucose Biosensor

A novel liposomal nanocomposite with biocompatibility and conductivity, Au@ILs-polysome, was fabricated and first utilized as the electrode material to immobilize the redox enzyme glucose oxidase (GOD) for the sensitive determination of glucose. Ionic liquids (ILs)-based polysome (ILs-polysome) was prepared via the radical polymerization of ILs based liposome (ILs-liposome) and improved by ion exchange with chloroauric acid to prepare Au nanoparticles (Au NPs) modified ILs based polysome (Au@ILs-polysome). The morphology, surface properties, and structure of Au@ILs-polysome were characterized; the results suggest that the nanocomposite exhibited excellent stability on the surface of solid electrodes without fusion. Electrochemical impedance spectroscopy (EIS) demonstrated that the nanocomposite had enhanced conductivity. Cyclic voltammetry (CV) shows that the direct electron transfer of GOD was achieved on the GOD/Au@ILs-polysome/GCE electrode since the Au@ILs-polysome provided a biocompatible microenvironment that made the immobilized enzyme stay natural and active. Differential pulse voltammetry (DPV) demonstrates that the GOD/Au@ILs-polysome/GCE electrode exhibited improved electrocatalytic activity compared with the GOD/ILs-polysome/GCE electrode. The electrochemical sensor exhibited a low detection limit of 0.02 mM, high sensitivity of 32.52 µA mM−1 cm−2, high selectivity toward glucose, and good stability. The practical application of the sensor was verified by the determination of glucose in human serum. The multi-component liposomal nanocomposites possess universal significance in protein-based direct electrochemical devices while offering a facile route to fabricating a highly sensitive glucose sensor for practical clinical diagnosis.

Efficient and rapid synthesis of ultrathin nickel-metal organic framework nanosheets for the sensitive determination of glucose

Ultrathin metal–organic frameworks (MOFs) have been traditionally synthesized by time-consuming hydrothermal or sonication procedures, thereby hampering the cost-effectiveness and widespread applicability. This study introduces an efficient and rapid one-pot synthesis route to ultrathin nickel-metal organic framework (Ni-MOFNs) of nanosheet architecture. The synthesized MOF was characterized using XRD, XPS, Raman spectroscopy, AFM, and FE-TEM analysis. The MOF was successfully applied for the sensitive determination of glucose under alkaline conditions. The non-enzymatic glucose sensor reported in this work offers superior analytical performances with a wide linear range (25–3150 μM), a low detection limit (0.6 µM), and high sensitivity (0.4023 mAmM-1cm−2). Moreover, it can also be applied for the determination of glucose in human blood serum with the relative standard deviation (RSD) of 1.3–4.2%, showing the high precision of the sensor in practical applications. This study opens a new rapid synthesis route to ultrathin Ni-MOF, which will supplement the established synthesis routes of Ni-MOF for sensor and electronic applications.

B,N-Doped PdRu Aerogels as High-Performance Peroxidase Mimics for Sensitive Detection of Glucose.

Among plentiful porous nanomaterials, noble metal aerogels taken as nanozymes attract broad attention in sensing applications with their distinct enzyme mimic functions. In the catalytic field, the heteroatom doping strategy is a kind of way with great promise in improving the enzyme mimic activity of noble metal aerogels. In this experiment, we find a type of creative materials that were prepared by the fast and simple method. Due to the unique porous structure and synergetic effect from doped atoms, PdRu aerogels co-doped with boron and nitrogen (B, N-PdRu aerogels) were prepared using NH3BH3 as a reductant, which present improved peroxidase mimicking activity. With the existence of H2O2, the oxidation of 3,3',5,5'-tetramethylbenzidine was catalyzed by B, N-PdRu aerogels fairly efficiently, whose solution would be a blue appearance at optimum absorption wavelength 652 nm. Thus, by the tandem reaction bound to the enzyme glucose oxidase, the B, N-PdRu aerogels can be used for the sensitive determination of glucose. The new method has a good linear detection effect for glucose in the range of 10 μM to 2 mM. The minimum limit of detection can reach as low as 6 μM. This work will contribute to research on the rational design of metal aerogels based on the heteroatomic doping strategy and enhance the corresponding performance for a variety of applications.

Monitoring the mechanism of anti-cancer agents to inhibit colorectal cancer cell proliferation: Enzymatic biosensing of glucose combined with molecular docking

Glucose, a major energy source in cellular metabolism, has a significant role in cell growth. The increase in glucose uptake is a distinguishing hallmark in cancer cells. A key step in glucose utilization is the transport of glucose to the cancer cells for supplying their additional energy. The glucose transporter (or GLUT) family is a membrane protein which facilitates the uptake of glucose in most cancer cell types. Given the increased glucose level in cancer cells and the regulatory role of GLUTs in glucose uptake, it is required to combine both experimental and theoretical studies to develop new methods to monitor cell proliferation. Herein, for the first time, a new strategy was proposed to evaluate the cell proliferation of HT-29 based on glucose consumption in the presence of resveratrol (RSV) as an anticancer agent. A hybrid nanocomposite of carbon nanofibers and nitrogen-doped graphene quantum dots was used to design an enzymatic sensor for the selective and sensitive determination of glucose in cancer cells. The results obtained from the voltammetric technique were compared with the conventional colorimetric assay. A good correlation was observed between the proliferation rate and glucose utilization by cancer cells. As it was observed, RSV induces a decrease in glucose consumption, indicating lower glucose uptake efficiency for HT-29 cells. Molecular docking studies reveal that RSV can block the interaction of glucose with the GLUT family. This is one of the possible mechanisms for the decrease of glucose level followed by the reduction of cell proliferation in the presence of RSV. Compared with traditional methods, in vitro electrochemical techniques benefit from simple, nontoxic, sensitive and low-cost detection assays and hence serve as a novel tool to pursue the growth inhibition of cancer cell in response to anti-cancer agents.

Highly sensitive non-enzymatic electrochemical glucose sensor surpassing water oxidation interference.

An electrochemical non-enzymatic sensor based on a NiVP/Pi material was developed for the selective and sensitive determination of glucose. The novel sensor showed a high sensitivity of 6.04 mA μM-1 cm-2 with a lowest detection limit of 3.7 nM in a wide detection range of 100 nM-10 mM. The proposed sensor exhibited a superior selectivity without any interference from the oxygen evolution reaction during glucose sensing. We also found that this glucose sensor showed negligible interference from various interferents, such as ascorbic acid, uric acid, dopamine and sodium chloride. Additionally, a novel flexible sensor was developed by coating the NiVP/Pi over Whatman filter paper, which exhibited two linear ranges of 100 nM to 1 μM and 100 μM to 10 mM with an ultra-sensitivity of 1.130 mA μM-1 cm-2 and 0.746 mA μM-1 cm-2, respectively, in 0.1 M NaOH. The proposed sensor was tested with human blood serum samples demonstrating its practical application. Our findings provide a new route by fine tuning the composition of nickel and vanadium that sheds new light on better understanding the processes. This NiVP/Pi-based sensor offers a new approach towards the electrochemical detection of glucose, enabling glucose monitoring in a convenient way.

Sensitive colorimetric glucose sensor by iron-based nanozymes with controllable Fe valence.

The proportion of Fe2+ and Fe3+ in Fe-based nanozymes is a key point in determining their catalytic activity. However, it is hard to adjust the Fe2+/Fe3+ ratio in nanozyme systems to achieve the best catalytic performance. In this work, we successfully regulate Fe2+/Fe3+ ratios in a wide range of 0.81-1.45 based on a novel porous platform of Fe doped silica hollow spheres. The homogeneous distribution and stable fixation of Fe components in Fe doped silica hollow spheres facilitate the valence regulation of Fe in the reduction heating in H2/Ar. When the Fe doped spheres (FeOx@SHSs) were used as nanozymes, different Fe2+/Fe3+ ratios have shown to influence the peroxidase-like catalytic activity greatly. The highest activity at the ratio of 1.41 should be due to the combined effects of the accelerated reaction rate by Fe2+ and the enhanced catalytic cycle efficiency by Fe3+. The FeOx@SHSs-based nanozyme is further applied to construct a facile colorimetric biosensing system, which exhibited extremely sensitive determination of glucose. This work presents an effective platform for controlling Fe valences and optimizing the peroxidase-like activity for catalytic processes or sensing systems.

Nanoporous silk films with capillary action and size-exclusion capacity for sensitive glucose determination in whole blood.

In optical biosensing, silk fibroin (SF) appears as a promising alternative where other materials, such as paper, find limitations. Besides its excellent optical properties and unmet capacity to stabilize biomacromolecules, SF in test strips exhibits additional functions, i.e. capillary pumping activity of 1.5 mm s-1, capacity to filter blood cells thanks to its small, but tuneable, porosity and enhanced biosensing sensitivity. The bulk functionalization of SF with the enzymes glucose oxidase and peroxidase and the mediator ABTS produces colourless and transparent SF films that respond to blood glucose increasing 2.5 times the sensitivity of conventional ABTS-based assays. This enhanced sensitivity results from the formation of SF-ABTS complexes, where SF becomes part of the bioassay. Additionally, SF films triple the durability of most stable cellulose-based sensors. Although demonstrated for glucose, SF microfluidic test strips may incorporate other optical bioassays, e.g. immunoassays, with the aim of transferring them from central laboratories to the place of patient's care.

Display of glucose oxidase on Bacillus subtilis spore surface and preparation for enzyme electrode

Glucose biosensor is currently the most common electrochemical biosensor. Most glucose biosensors are prepared by modifying glucose oxidase on the electrode surface. However, in the process of electrode immobilization, enzyme purification is required, which increases the cost and has become a bottleneck in the field of development of immobilized enzyme electrodes. In this study, glucose oxidase (GOD) was displayed on the surface of Bacillus subtilis using the spore capsid protein CotX as an anchor protein. By Western blotting analysis, immunofluorescence analysis and enzyme activity detection, GOD was effectively expressed on the surface of spores, and recombinant spores (Spore-GOD) were obtained by fermentation. The graphene oxide/prussian blue deposition film modified glassy carbon electrode was prepared by the drop coating method and the electrodeposition method. The surface of the modified electrode was fixed with Spore-GOD, and finally covered with a layer of Nafion solution to make an electrochemical biosensor for sensitive determination of glucose. The cyclic voltammogram of glucose on the enzyme electrode sensor showed a well-defined oxidation peak at 0.42 V, and the redox peak current has a good linear relationship with the glucose concentration in the range of 0.1-7.0 mmol/L. The calibration curve equation is: I=1.305C(glucose)+3.639 (R²=0.992 9), and its detection limit is 7.5 μmol/L (S/N=3). This modified electrode has good conductivity, stability and reproducibility, and can be used for the analysis and determination of glucose.

Facile preparation of novel Pd nanowire networks on a polyaniline hydrogel for sensitive determination of glucose.

In this study, novel Pd nanowire networks (PdNW) grown on three-dimensional polyaniline hydrogel (3D-PANI) were prepared via a facile one-step electrodeposition approach at a constant potential of - 0.2V and further utilized as an electrochemical sensing material for sensitive determination of glucose in alkaline medium. Compared with the sensor based on Pd nanofilm (PdNF)/3D-PANI prepared by electrodeposition at - 0.9V, the sensor based on PdNW/3D-PANI presented substantially enhanced electrocatalytic activity towards glucose oxidation, with an excellent sensitivity of 146.6μAmM-1cm-2, a linear range from 5.0 to 9800μM, and a low detection limit of 0.7μM and was, therefore, demonstrated to be available for the determination of glucose in human serum. These findings are likely attributed to the combination of advantages of both PdNW and 3D-PANI, which outperformed most other Pd-based non-enzymatic glucose sensors reported earlier. Moreover, this non-enzymatic electrochemical sensor based on PdNW/3D-PANI may serve as an alternative tool for the assay of glucose and possibly other biomolecules. Graphical abstract.

Tunable electrochemical synthesis of 3D nucleated microparticles like Cu-BTC MOF-carbon nanotubes composite: Enzyme free ultrasensitive determination of glucose in a complex biological fluid

The present study describes the fabrication of 3D nucleated microparticles like Cu-MOF (MPsLCu-MOF)-SWCNTs composite on glassy carbon electrode (GCE) by electrodeposition and applied as a sensor for the sensitive determination of glucose in human saliva samples. First, SWCNTs were deposited on GCE by potential cycling between 0.0 V to -1.0 V and then, Cu-MOF was electrodeposited on SWCNTs modified GCE using a ligand, 1,3,5-benzene tricarboxylic acid (BTC), triethylamine hydrochloride and copper salt. The SEM studies showed the formation of MPsLCu-MOF on SWCNTs as well as on bare GCE with 1 μm size. The impedance studies showed that the heterogeneous electron transfer rate constant of [Fe(CN)6]3-/4- was higher at SWCNTs-MPsLCu-MOF than bare GCE and SWCNTs and MPsLCu-MOF modified GCEs. Then, the composite electrode was utilized for non-enzymatic detection of glucose. The SWCNTs-MPsLCu-MOF modified electrode showed a well-defined sharp oxidation peak at 0.45 V with enhanced current than bare GCE and SWCNTs and MPsLCu-MOF modified GCEs. As the concentration of glucose increases from 10-160 × 10-6 M, the oxidation current also increases without shifting its oxidation potential. The present composite modified electrode was also used to determine glucose in the linear range of 20 × 10-9 M to 80 × 10-6 M by amperometry with a LOD of 1.72 × 10-9 M (S/N=3) and a superior sensitivity of 573 μA mM−1 cm−2. Finally, the composite fabricated electrode was exploited for real-time analysis of glucose in human saliva samples and satisfactory results were obtained.

Bimetallic PtAu alloy nanomaterials for nonenzymatic selective glucose sensing at low potential

Electrochemical nonenzymatic glucose sensing meets the challenge of excellent selectivity and the minimum poisoning effect of the electrode. Bimetallic alloys based on Pt have distinct synergistic characteristics and offer remarkable anti-poisoning capability and electrocatalytic performance for sensitive and selective glucose sensing at low potential. Bimetallic PtAu alloy nanomaterials loaded into nanocarbon carrier (PtAu/C) were successfully fabricated. The morphology and structure of PtAu bimetallic alloy were observed. The voltammetric response of the PtAu/C modified electrodes towards glucose oxidation in NaOH revealed significant enhanced compared with Pt/C or Au/C. PtAu (1:1)/C with 0.4 wt% content of Pt was used for selective glucose detection at a low potential of −0.33 V (vs. SCE). Interfering substances revealed inert and ignorable analytical influence on glucose detection. Furthermore, DPV was applied for sensitive determination of glucose. A linear relationship was found between peak current and glucose concentration within the range of 0.01–10 mM with the limit of detection (LOD) of 3 μM. Validation in human serum samples indicated that the PtAu (1:1)/C (0.4 wt% Pt) modified electrode accurately detected glucose. The PtAu bimetallic alloy exhibited a bright prospect for the glucose analysis of real samples.

DNA-scaffold copper nanoclusters integrated into a cerium(III)-triggered Fenton-like reaction for the fluorometric and colorimetric enzymatic determination of glucose.

A fluorometric and colorimetric method are described for the determination of hydrogen peroxide and glucose by integrating copper nanoclusters (CuNCs) into a Fenton-like reaction. The mechanism mainly depends on the fast formation of long-strand DNA-templated CuNCs with strong red fluorescence (with excitation/emission maxima at 340/640nm) in the absence of H2O2. The DNA can be cleaved into short-oligonucleotide fragments by hydroxy radicals as formed in the Ce(III)-triggered Fenton-like reaction in the presence of H2O2. As a result, short-strand DNA loses the ability as a template for the formation of CuNCs. This leads to a decrease of fluorescence. The colorimetric assay, in turn, is based on the oxidation of colorless Ce(III) ions to the distinctly yellow Ce(IV) ions (with an absorption maximum at 400nm) by H2O2. Compared with those assays based on the use of enzyme mimics, this method does not require any chromogenic substrates such as ABTS and TMB. Based on the dual-signal readout platform, we successfully achieved the detection of H2O2 and glucose. LODs are as low as 0.266μM and 2.92μM. The methods were applied to the sensitive determination of glucose by using glucose oxidase (GOx) which catalyzes the oxidization of glucose to produce H2O2. The practical application was demonstrated by determination of glucose in human serum, with apparent recoveries of 98.4-101.9% and 99.1-105.6%, respectively. The concentration of glucose ranges from 1 to 500μM and 50 to 600μM based on the dual-signal readout platform, respectively. This fluorometric and colorimetric dual-mode strategy will pave a new avenue for constructing effective assays for H2O2-related analytes in biochemical and clinical applications. Graphical abstractSchematic representation of a fluorometric and colorimetric dual-readout strategy for the sensitive determination of hydrogen peroxide and glucose. The assay has been designed by integrating copper nanoclusters into aCe(III)-triggered Fenton-like reaction.

Copper Nanoparticle and Nitrogen Doped Graphite Oxide Based Biosensor for the Sensitive Determination of Glucose.

Copper nanoparticles with the diameter of 50 ± 20 nm decorated nitrogen doped graphite oxide (NGO) have been prepared through a simple single step carbonization method using copper metal-organic framework (MOF), [Cu2(BDC)2(DABCO)] (where BDC is 1,4-benzenedicarboxylate, and DABCO is 1,4-Diazabicyclo[2.2.2]octane) as precursor. The surface morphology, porosity, surface area and elemental composition of CuNPs/NGO were characterized by various techniques. The as-synthesized CuNPs/NGO nanomaterials were coated on commercially available disposable screen-printed carbon electrode for the sensitive determination of glucose. We find that the modified electrode can detect glucose between 1 μM and 1803 μM (linear range) with good sensitivity (2500 μA mM−1 cm−2). Our glucose sensor also possesses low limits of detection (0.44 μM) towards glucose determination. The highly selective nature of the fabricated electrode was clearly visible from the selectivity studies. The practicability of CuNPs/NGO modified electrode has been validated in the human serum samples. The storage stability along with better repeatability and reproducibility results additionally substantiate the superior electrocatalytic activity of our constructed sensor towards glucose.

Non-enzymatic voltammetric glucose sensor made of ternary NiO/Fe3O4-SH/para-amino hippuric acid nanocomposite

The present study has been focused on a facile strategy to fabricate an electrochemical sensor based on nickel oxide decorated Fe3O4 nanoparticles/poly(p-aminohippuric acid)-sodium dodecyl sulfate nanocomposite immobilized on the modified glassy carbon electrode (NiO@ Fe3O4-SH/PPAH-SDS/GCE). PPAH-SDS film was prepared by electropolymerization and nickel oxide nanostructures were deposited on the Fe3O4-SH/PPAH-SDS by electrochemical method. The as-synthesized nanocomposite was characterized by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS) for morphological and elemental analysis, respectively and the electrochemical characteristics were studied by the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) methods. The differential pulse voltammetry (DPV) was used for the sensitive determination of glucose in alkaline solution in two linear concentration ranges, 0.1–10.0μM and 10.0–300.0μM, with a detection limit of 0.13μM (S/N=3) based on the first linear range. Meanwhile, the presented sensor showed a promising performance for the quantification of glucose in human serum as a real sample reflecting the practicability of fabricated glucose sensor.

One‐step synthesis of nitrogen, boron co‐doped fluorescent carbon nanoparticles for glucose detection

Heteroatom-doped carbon nanoparticles (CNPs) have attracted considerable attention due to an effective improvement in their intrinsic properties. Here, a facile and simple synthesis of nitrogen, boron co-doped carbon nanoparticles (NB-CNPs) from a sole precursor, 3-aminophenylboronic acid, was performed via a one-step solid-phase approach. Because of the presence of boronic acid, NB-CNPs can be used directly as a fluorescent probe for glucose. Based on a boronic acid-triggered specific reaction, we developed a simple NB-CNP probe without surface modification for the detection of glucose. When glucose was introduced, the fluorescence of NB-CNPs was suppressed through a surface-quenching states mechanism. Obvious fluorescence quenching allowed the highly sensitive determination of glucose with a limit of detection of 1.8μM. Moreover, the proposed method has been successfully used to detect glucose in urine from people with diabetes, suggesting potential application in sensing glucose.

Synthesis of hierarchical three‐dimensional CuO spindles for highly sensitive glucose determination

Hierarchical three-dimensional copper oxide (CuO) spindles were prepared via a hydrothermal process. The as-prepared CuO spindles assembled from nanoslices were characterised by scanning electron microscopy and transmission electron microscopy. The obtained hierarchical structure exhibited numerous particle boundaries acting as active sites for glucose oxidation in an alkaline solution. Chronomaperometric studies showed that under an optimal applied potential of +0.5 V versus Ag/AgCl, the as-prepared CuO electrode exhibited a broad detection range from 0.001 to 3.0 mM with a sensitivity of ca. 3000 μA mM−1 cm−2 and a low detection limit of 0.3 μM. The CuO spindle electrode also demonstrated excellent selectivity to glucose oxidation in the presence of several electro-active species.

Nitrogen-Doped Carbon Dots as A New Substrate for Sensitive Glucose Determination.

Nitrogen-doped carbon dots are introduced as a novel substrate suitable for enzyme immobilization in electrochemical detection metods. Nitrogen-doped carbon dots are easily synthesised from polyacrylamide in just one step. With the help of the amino group on chitosan, glucose oxidase is immobilized on nitrogen-doped carbon dots-modified carbon glassy electrodes by amino-carboxyl reactions. The nitrogen-induced charge delocalization at nitrogen-doped carbon dots can enhance the electrocatalytic activity toward the reduction of O2. The specific amino-carboxyl reaction provides strong and stable immobilization of GOx on electrodes. The developed biosensor responds efficiently to the presence of glucose in serum samples over the concentration range from 1 to 12 mM with a detection limit of 0.25 mM. This novel biosensor has good reproducibility and stability, and is highly selective for glucose determination under physiological conditions. These results indicate that N-doped quantum dots represent a novel candidate material for the construction of electrochemical biosensors.

Amperometric biosensor based on electrochemically reduced graphene oxide/poly(m-dihydroxybenzene) composites for glucose determination

A novel amperometric biosensor was designed via immobilization of glucose oxidase (GOD) into the composite films of electrochemically reduced graphene oxide (RGO) and poly(m-dihydroxybenzene) (PmDB). PmDB was first electrodeposited onto the surface of a glassy carbon electrode by electrochemical polymerization of m-dihydroxybenzene in the presence of graphene oxide (GO). Next, the obtained GO/PmDB composites were electrochemically reduced to RGO/PmDB at a negative potential. The RGO/PmDB composites were characterized by scanning electron microscopy (SEM), cyclic voltammetry (CV) and differential pulse voltammetry (DPV). The RGO/PmDB composites exhibited high electrocatalytic activity towards the oxidation of hydrogen peroxide (H2O2), and therefore, they were used for sensitive glucose determination by immobilizing GOD within the composite films. The as-prepared glucose biosensor exhibited a linear response ranging from 0.5 to 15 mM, a low detection limit of 0.023 mM (S/N = 3). Also, the RGO- /PmDB-based glucose sensor displayed excellent selectivity as well as good reproducibility and stability.