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1.
Li J  Yu J  Zhao F  Zeng B 《Analytica chimica acta》2007,587(1):33-40
The direct electrochemistry of glucose oxidase (GOD) entrapped in nano gold particles (NAs)-N,N-dimethylformamide (DMF)-1-butyl-3-methylimidazolium hexafluophosphate (BMIMPF6) composite film on a glassy carbon electrode (NAs-DMF-GOD (BMIMPF6)/GC) has been investigated for first time. The immobilized GOD exhibits a pair of well-defined reversible peaks in 0.050 M pH 5 phosphate solutions (PS), resulting from the redox of flavin adenine dinucleotide (FAD) in GOD. The peak currents are three times as large as those of GOD-NAs-DMF film coated GC electrode (i.e. NAs-DMF-GOD (water)/GC). In addition, the NAs-DMF-GOD (BMIMPF6) composite material has higher thermal stability than NAs-DMF-GOD (water). Results show that ionic liquid BMIMPF6, DMF and NAs are requisite for GOD to exhibit a pair of stable and reversible peaks. Without any of them, the peaks of GOD become small and unstable. Upon the addition of glucose, the peak currents of GOD decrease and a new cathodic peak occurs at −0.8 V (versus SCE), which corresponds to the reduction of hydrogen peroxide (H2O2) generated by the catalytic oxidation of glucose. The peak current of the new cathodic peak and the glucose concentration show a linear relationship in the ranges of 1.0 × 10−7 to 1.0 × 10−6 M and 2.0 × 10−6 to 2.0 × 10−5 M. The kinetic parameter Imax of H2O2 is estimated to be 1.19 × 10−6 A and the apparent Km (Michaelis-Menten constant) for the enzymatic reaction is 3.49 μM. This method has been successfully applied to the determination of glucose in human plasma and beer samples, and the average recoveries are 97.2% and 99%, respectively.  相似文献   

2.
Amino acid ionic liquids (AAILs) have attracted much attention due to their special chemical and physical properties, especially their outstanding biocompatibility and truly green aspect. In this work, a novel electrochemical biosensing platform based on AAILs/carbon nanotubes (CNTs) composite was fabricated. AAILs were used as a novel solvent for glucose oxidase (GOD) and the GOD-AAILs/CNTs/GC electrode was conveniently prepared by immersing the carbon nanotubes (CNTs) modified glassy carbon (GC) electrode into AAILs containing GOD. The direct electrochemistry of GOD on the GOD-AAILs/CNTs/GC electrode has been investigated and a pair of reversible peaks was obtained by cyclic voltammetry. The immobilized glucose oxidase could retain bioactivity and catalyze the reduction of dissolved oxygen. Due to the synergic effect of AAILs and CNTs, the GOD-AAILs/CNTs/GC electrode shows excellent electrocatalytic activity towards glucose with a linear range from 0.05 to 0.8 mM and a detection limit of 5.5 μM (S/N = 3). Furthermore, the biosensor exhibits good stability and ability to exclude the interference of commonly coexisting uric and ascorbic acid. Therefore, AAILs/CNTs composite can be a good candidate biocompatible material for the direct electrochemistry of the redox-active enzyme and the construction of third- generation enzyme sensors.  相似文献   

3.
A water-dispersible multi-walled carbon nanotubes (MWCNTs) derivative, MWCNTs-1-one-dihydroxypyridine (MWCNTs-Py) was synthesis via Friedel–Crafts chemical acylation. Raman spectra demonstrated the conjugated level of MWCNTs-Py was retained after this chemical modification. MWCNTs-Py showed dual hydrogen peroxide (H2O2) and glucose detections without mutual interference by adjusting pH value. It was sensitive to H2O2 in acidic solution and displayed the high performances of sensitivity, linear range, response time and stability; meanwhile it did not respond to H2O2 in neutral solution. In addition, this positively charged MWCNTs-Py could adsorb glucose oxidase (GOD) by electrostatic attraction. MWCNTs-Py-GOD/GC electrode showed the direct electron transfer (DET) of GOD with a pair of well-defined redox peaks, attesting the bioactivity of GOD was retained due to the non-destroyed immobilization. The high surface coverage of active GOD (3.5 × 10−9 mol cm−2) resulted in exhibiting a good electrocatalytic activity toward glucose. This glucose sensor showed high sensitivity (68.1 μA mM−1 cm−2) in a linear range from 3 μM to 7 mM in neutral buffer solution. The proposed sensor could distinguish H2O2 and glucose, thus owning high selectivity and reliability.  相似文献   

4.
A simple procedure has been used for preparation of modified glassy carbon electrode with carbon nanotubes and copper complex. Copper complex [Cu(bpy)2]Br2 was immobilized onto glassy carbon (GC) electrode modified with silicomolybdate, α-SiMo12O404− and single walled carbon nanotubes (SWCNTs). Copper complex and silicomolybdate irreversibly and strongly adsorbed onto GC electrode modified with CNTs. Electrostatic interactions between polyoxometalates (POMs) anions and Cu-complex, cations mentioned as an effective method for fabrication of three-dimensional structures. The modified electrode shows three reversible redox couples for polyoxometalate and one redox couple for Cu-complex at wide range of pH values. The electrochemical behavior, stability and electron transfer kinetics of the adsorbed redox couples were investigated using cyclic voltammetry. Due to electrostatic interaction, copper complex immobilized onto GC/CNTs/α-SiMo12O404− electrode shows more stable voltammetric response compared to GC/CNTs/Cu-complex modified electrode. In comparison to GC/CNTs/Cu-complex the GC/CNTs/α-SiMo12O404− modified electrodes shows excellent electrocatalytic activity toward reduction H2O2 and BrO3 at more reduced overpotential. The catalytic rate constants for catalytic reduction hydrogen peroxide and bromate were 4.5(±0.2) × 103 M−1 s−1 and 3.0(±0.10) × 103 M−1 s−1, respectively. The hydrodynamic amperommetry technique at 0.08 V was used for detection of nanomolar concentration of hydrogen peroxide and bromate. Detection limit, sensitivity and linear concentration range proposed sensor for bromate and hydrogen peroxide detection were 1.1 nM and 6.7 nA nM−1, 10 nM-20 μM, 1 nM, 5.5 nA nM−1 and 10 nM-18 μM, respectively.  相似文献   

5.
The surface nanocrystallization of glassy carbon (GC) electrode was carried out using cyclic voltammetry in anhydrous dimethylformamide containing 0.05 M tetra-n-butylammonium bromine, and carbon nanoparticles with diameter of 10–40 nm were formed on the electrode surface. Comparing with the typical GC electrode, the surface-nanocrystalline GC (SNGC) electrode showed higher electrocatalytic activity for direct electrochemistry of glucose oxidase (GOD) due to higher proportion of edge sites presented on the surface of the SNGC electrode. Because of the surface nanocrystallization of the electrode, a pair of well-defined and quasi-reversible redox peaks of the immobilized GOD was observed for the first time on the GC electrode.  相似文献   

6.
XU  Jiming  HAN  Wenxia  YIN  Qifan  SONG  Jie  ZHONG  Hui 《中国化学》2009,27(11):2197-2202
The direct electrochemistry of glucose oxidase (GOD) was achieved based on the immobilization of GOD on a natural nano‐structural attapulgite (ATP) clay film modified glassy carbon (GC) electrode. The immobilized GOD displayed a pair of well‐defined quasi‐reversible redox peaks with a formal potential (E0′) of ?457.5 mV (vs. SCE) in 0.1 mol·L?1 pH 7.0 phosphate buffer solution. The peak current was linearly dependent on the scan rate, indicating that the direct electrochemistry of GOD in that case was a surface‐controlled process. The immobilized glucose oxidase could retain bioactivity and catalyze the oxidation of glucose in the presence of ferrocene monocarboxylic acid (FMCA) as a mediator with the apparent Michaelis‐Menten constant Kappm of 1.16 mmol·L?1. The electrocatalytic response showed a linear dependence on the glucose concentration ranging widely from 5.0×10?6 to 6.0×10?4 mol·L?1 (with correlation coefficient of 0.9960). This work demonstrated that the nano‐structural attapulgite clay was a good candidate material for the direct electrochemistry of the redox‐active enzyme and the construction of the related enzyme biosensors. The proposed biosensors were applied to determine the glucose in blood and urine samples with satisfactory results.  相似文献   

7.
In the present study, a novel and ultrasensitive electrochemiluminescence (ECL) immunosensor based on luminol cathodic ECL was fabricated by using Au nanoparticles and Pt nanoparticles (nano-AuPt) electrodeposited on graphene–carbon nanotubes nanocomposite as platform for the detection of carcinoembryonic antigen (CEA). For this introduced immunosensor, graphene (GR) and single wall carbon nanotubes (CNTs) dispersed in chitosan (Chi-GR-CNTs) were firstly decorated on the bare gold electrode (GE) surface. Then nano-AuPt were electrodeposited (DpAu-Pt) on the Chi-GR-CNTs modified electrode. Subsequently, glucose oxidase (GOD) was employed to block the non-specific sites of electrode surface. When glucose was present in the working buffer solution, GOD immediately catalyzed the oxidation of glucose to in situ generate hydrogen peroxide (H2O2), which could subsequently promote the oxidation of luminol with an amplified cathodic ECL signal. The proposed immunosensor was performed at low potential (−0.1 to 0.4 V) and low concentration of luminol. The CEA was determined in the range of 0.1 pg mL−1 to 40 ng mL−1 with a limit of detection down to 0.03 pg mL−1 (S N−1 = 3). Moreover, with excellent sensitivity, selectivity, stability and simplicity, the as-proposed luminol-based ECL immunosensor provided great potential in clinical applications.  相似文献   

8.
We report here the direct electron transfer of GOD and a novel glucose biosensor based on carbon-decorated ZnO(C–ZnO) nanowire array electrode. The C–ZnO nanowire array provides a novel platform for fast direct electrochemistry of GOD, and its based biosensor shows very high sensitivity and low detection limit. Based on the direct electrochemistry of horseradish peroxidase (HRP), the H2O2 biosensing application is further demonstrated using this new C–ZnO array architecture. The high conductivity of carbon and good electron transfer capability of ZnO nanowires, along with their low cost and biocompatibility make the C–ZnO nanowire array a promising platform for direct electrochemistry of enzymes and mediator-free enzymatic biosensors.  相似文献   

9.
Aligned carbon nanotubes (ACNTs) electrode has been developed for the direct protein electrochemistry and enzyme-biosensor study involving two types of nanoparticles. Pt nanoparticles (Ptnano) were electro-modified on the ACNTs’ each tube, greatly increasing the electrode surface area for locating protein and also its electronic transfer ability. Glucose oxidase (GOD) with chitosan (CS) and CdS nanoparticles electrochemically coated on each tube of ACNTs–Ptnano by the electrodeposition reaction of CS when pH value passing its pKa. The CdS nanoparticles between ACNTs electrode and GOD have stimulated the GOD’s direct electron transfer during its redox reaction of FAD/FADH2. The CS–GOD–CdS/ACNTs–Ptnano electrode also offer sensitive response to the substrate of glucose with detection limit of 46.8 μM (S/N = 3) and apparent Michaelis–Menten constant of 11.86 mM.  相似文献   

10.
S. Ashok Kumar 《Talanta》2007,72(2):831-838
The adsorption processes and electrochemical behavior of 4-nitroaniline (4-NA) adsorbed onto glassy carbon electrodes (GCE) have been investigated in aqueous 0.1 M nitric acid (HNO3) electrolyte solutions using cyclic voltammetry (CV). 4-NA adsorbs onto GCE surfaces, and upon potential cycling past −0.2 V, is transformed into the arylhydroxylamine (ArHA) derivative which exhibits a well-behaved pH dependent redox couple centered at 0.32 V at pH 1.5. It is noted as arylhydroxylamine modified glassy carbon electrodes (HAGCE). This modified electrode can be readily used as an immobilization matrix to entrap proteins and enzymes. In our studies, myoglobin (Mb) was used as a model protein for investigation. A pair of well-defined reversible redox peaks of Mb (Fe(III)-Fe(II)) was obtained at the Mb/arylhydroxylamine modified glassy carbon electrode (Mb/HAGC) by direct electron transfer between the protein and the GCE. The formal potential (E0), the apparent coverage (Γ*) and the electron-transfer rate constant (ks) were calculated as −0.317 V, 8.26 × 10−12 mol/cm2 and 51 ± 5 s−1, respectively. Dramatically enhanced biocatalytic activity was exemplified at the Mb/HAGC electrode by the reduction of hydrogen peroxide (H2O2), trichloroacetic acid (TCA) and oxygen (O2). The Mb/arylhydroxylamine film was also characterized by UV-visible spectroscopy (UV-vis), scanning electron microscope (SEM) indicating excellent stability and good biocompatibility of the protein in the arylhydroxylamine modified electrode. This new Mb/HAGC electrode exhibited rapid electrochemical response (2 s) for H2O2 and had good stability in physiological condition, showing the potential applicability of the films in the preparation of third generation biosensors or bioreactors based on direct electrochemistry of the proteins.  相似文献   

11.
A functional composite was prepared by mixing mesoporous carbon, glucose oxidase (GOD) and 1-butyl-3-methylimidazolium hexafluorophosphate, an ionic liquid, and characterized by SEM and RA-IR. The composite was filled in a microcavity to fabricate a paste microelectrode, demonstrating direct electrochemistry of GOD with a pair of well-defined redox peaks. The composite microelectrode was used as a glucose microsensor, showing good sensitivity over a concentration range from 10.0 to 80.0 μmol/L and a Michaelis–Menten constant of 2.42 μmol/L. This work demonstrates an efficient and accurate approach to study direct electrochemistry with potential applications in various enzymatic biosensors.  相似文献   

12.
《Electroanalysis》2006,18(11):1131-1134
The direct electrochemistry of glucose oxidase (GOD) was revealed at a carbon nanotube (CNT)‐modified glassy carbon electrode, where the enzyme was immobilized with a chitosan film containing gold nanoparticles. The immobilized GOD displays a pair of redox peaks in pH 7.4 phosphate buffer solutions (PBS) with the formal potential of about ?455 mV (vs. Ag/AgCl) and shows a surface‐controlled electrode process. Bioactivity remains good, along with effective catalysis of the reduction of oxygen. In the presence of dissolved oxygen, the reduction peak current decreased gradually with the addition of glucose, which could be used for reagentless detection of glucose with a linear range from 0.04 to 1.0 mM. The proposed glucose biosensor exhibited high sensitivity, good stability and reproducibility, and was also insensitive to common interferences such as ascorbic and uric acid. The excellent performance of the reagentless biosensor is attributed to the effective enhancement of electron transfer between enzyme and electrode surface by CNTs, and the biocompatible environment that the chitosan film containing gold nanoparticles provides for immobilized GOD.  相似文献   

13.
《Electroanalysis》2003,15(10):885-891
Initial results on the synthesis of a new conjugated diazonium salt of trans‐4‐cinnamic acid diazonium fluoroborate, which is used for the chemical modification of the glassy carbon (GC) electrode with trans‐4‐cinnamic acid groups through electrochemical reduction, and direct covalent immobilization of glucose oxidase (GOD) on the cinnamic acid groups are presented. The chemically modified GC electrode exhibits a good selectivity relative to the bare GC electrode for the various possible interfering compounds in glucose analysis: namely ascorbic acid and 4‐acetamidophenol. Covalent immobilization of GOD on the chemically modified GC electrode produces a biosensor which responds to glucose concentration changes in the presence of a soluble redox mediator (ferrocenemethanol). The chemical modification of GC by cinnamic acid groups is potentially useful for the attachment of other enzymes and biochemical reagents.  相似文献   

14.
A colloidal suspension of nanostructured poly(N-butyl benzimidazole)-graphene sheets (PBBIns-Gs) was used to modify a gold electrode to form a three-dimensional PBBIns-Gs/Au electrode that was sensitive to hydrogen peroxide (H2O2) in the presence of acetic acid (AcOH). The positively charged nanostructured poly(N-butyl benzimidazole) (PBBIns) separated the graphene sheets (Gs) and kept them suspended in an aqueous solution. Additionally, graphene sheets (Gs) formed “diaphragms” that intercalated Gs, which separated PBBIns to prevent tight packing and enhanced the surface area. The PBBIns-Gs/Au electrode exhibited superior sensitivity toward H2O2 relative to the PBBIns-modified Au (PBBIns/Au) electrode. Furthermore, a high yield of glucose oxidase (GOD) on the PBBIns-Gs of 52.3 mg GOD per 1 mg PBBIns-Gs was obtained from the electrostatic attraction between the positively charged PBBIns-Gs and negatively charged GOD. The non-destructive immobilization of GOD on the surface of the PBBIns-Gs (GOD-PBBIns-Gs) retained 91.5% and 39.2% of bioactivity, respectively, relative to free GOD for the colloidal suspension of the GOD-PBBIns-Gs and its modified Au (GOD-PBBIns-Gs/Au) electrode. Based on advantages including a negative working potential, high sensitivity toward H2O2, and non-destructive immobilization, the proposed glucose biosensor based on an GOD-PBBIns-Gs/Au electrode exhibited a fast response time (5.6 s), broad detection range (10 μM to 10 mM), high sensitivity (143.5 μA mM−1 cm−2) and selectivity, and excellent stability. Finally, a choline biosensor was developed by dipping a PBBIns-Gs/Au electrode into a choline oxidase (ChOx) solution for enzyme loading. The choline biosensor had a linear range of 0.1 μM to 0.83 mM, sensitivity of 494.9 μA mM−1 cm−2, and detection limit of 0.02 μM. The results of glucose and choline measurement indicate that the PBBIns-Gs/Au electrode provides a useful platform for the development of oxidase-based biosensors.  相似文献   

15.
Fei J  Wu K  Wang F  Hu S 《Talanta》2005,65(4):918-924
This paper describes glucose nanosensors based on the co-electrodeposition of a poly(vinylimidazole) complex of [Os(bpy)2Cl]+/2+ and glucose oxidase (GOD) on a low-noise carbon fiber nanoelectrodes (CFNE). The SEM image shows that the osmium redox polymer/enzyme composite film is uniform. The film modified CFNE exhibits the classical features of a kinetically fast redox couple bound to the electrode surface. A strong and stable electrocatalytic current is observed in the presence of glucose. Under the optimal experimental conditions, the nanosensor offers a highly sensitive and rapid response to glucose at an operating potential of 0.22 V. A wide linear dynamic rang of 0.01-15 mM range was achieved with a detection limit of 0.004 mM. Compared with the conventional gold electrode, the nanosensor possessed higher sensitivity and longer stability. Successful attempts were made in real time monitoring rabbit blood glucose levels.  相似文献   

16.
Gendi Jin 《Talanta》2009,80(2):858-1080
A new petentiometric method to determine peroxide hydrogen and glucose had been studied. This method had been applied on the petentiometric determination of peroxide hydrogen and glucose in the total ionic strength adjustment buffer (TISAB) (pH 7.5) solution with the glassy electrode modified by the calix[4]arene. The glassy carbon electrode covered with the calix[4]arene depended on the H2O2 concentration in the range of log[H2O2] from −3.3 to −1.2 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 65.6 ± 3 mV and the detection limit of peroxide hydrogen was 4.0 × 10−5 mol L−1. The glassy carbon electrode covered with the calix[4]arene depended on the glucose concentration in the range of log[glucose] from −3.6 to −2.8 in the solution of TISAB (pH 7.5) with nearly Nernstian slope of about 50.2 ± 2 mV and the detection limit of glucose was 2.0 × 10−5 mol L−1. The electrode had the good selectivity, sensitivity, stability and repeatability.  相似文献   

17.
The direct electrochemistry of glucose oxidase (GOD) immobilized in a modified electrode based on a composite film of exfoliated graphite nanosheets (GNSs) and Nafion has been investigated for the first time. Direct electron communication between GOD and the electrode was achieved with a fast electron transfer rate (12.6 s?1). In addition, the bioactivity of GOD was retained after immobilization in the composite film and glucose could be determined based on the decrease of the electrocatalytic response of the reduced form of GOD to dissolved oxygen. The resulting biosensor exhibited higher sensitivity (3.4 μA mM?1). Considering much lower cost of GNSs and ready preparation from graphite, the GNSs-based modified electrode described here is superior to the carbon nanotubes (CNTs)-based modified electrodes and should have wide applications in third-generation biosensors, bioelectronics and electrocatalysis.  相似文献   

18.
A novel electrochemical platform based on nickel oxide (NiO) nanoparticles and TiO2–graphene (TiO2–Gr) was developed for the direct electrochemistry of glucose oxidase (GOD). The electrochemical behavior of the sensor was studied using cyclic voltammetry and chronoamperometry. The experimental results demonstrated that the nanocomposite well retained the activity of GOD and the modified electrode GOD/NiO/TiO2–Gr/GCE exhibited excellent electrocatalytic activity toward the redox of GOD as evidenced by the significant enhancement of redox peak currents in comparison with bare GCE. The biosensor responded linearly to glucose in the range of 1.0–12.0?mM, with a sensitivity of 4.129?μA?mM?1 and a detection limit of 1.2?×?10?6?M under optimized conditions. The response time of the biosensor was 3?s. In addition, the developed biosensor possessed good reproducibility and stability, and there was negligible interference from other electroactive components.  相似文献   

19.
将稀土纳米材料Er2O3用于构建葡萄糖生物传感器。Er2O3和氧化石墨烯形成复合基底,将葡萄糖氧化酶(GOD)固载在玻碳电极表面。首先利用SEM和XRD技术对所制备的Er2O3和氧化石墨烯纳米材料进行表征。利用EIS和CV对整个生物传感器制备过程进行表征。Er2O3的存在能有效的保持GOD的生物活性并加速其电子传递速率。由于Er2O3和氧化石墨烯之间的协同效应,使得制备的传感器具有一对良好的氧化还原峰,证实GOD和电极之间的直接传递性能。当用于对葡萄糖的电催化氧化时,传感器的CV响应随着葡萄糖浓度的增加而变弱。在葡萄糖浓度为1~10 mmol·L-1范围内,CV响应值与葡萄糖浓度成线性关系。此外,传感器具有好的稳定性和重现性。  相似文献   

20.
将稀土纳米材料Er2O3用于构建葡萄糖生物传感器。Er2O3和氧化石墨烯形成复合基底,将葡萄糖氧化酶(GOD)固载在玻碳电极表面。首先利用SEM和XRD技术对所制备的Er2O3和氧化石墨烯纳米材料进行表征。利用EIS和CV对整个生物传感器制备过程进行表征。Er2O3的存在能有效地保持GOD的生物活性并加速其与电极之间的电子传递。由于Er2O3和氧化石墨烯之间的协同效应,使得制备的传感器在CV图中呈现一对明显的氧化还原峰,证实GOD和电极之间的直接电子传递性能。当用于对葡萄糖的电催化氧化时,传感器的CV响应随着葡萄糖浓度的增加而变弱。在葡萄糖浓度为1~10 mmol·L-1范围内,CV响应值与葡萄糖浓度成线性关系。此外,传感器具有好的稳定性和重现性。  相似文献   

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