Reduced Graphene Oxide/Pt Nanoparticles/Zn‐MOF‐74 Nanomaterial for a Glucose Biosensor Construction

In this study, a new glucose biosensor was fabricated by immobilizing glucose oxidase (GOx) on platinum nanoparticles (Pt NPs) decorated reduced graphene oxide (rGO)/Zn‐MOF‐74 hybrid nanomaterial. Herein, the biosensor fused the advantages of rGO with those of porous Zn‐MOF and conductive Pt NPs. This has not only enlarged the surface area and porosity for the efficient GOx immobilization and faster mass transport, but also provided favorable electrochemical features such as high current density, remarkable electron mobility through metal nanoparticles, and improved electron transfer between the components. The GOx‐rGO/Pt NPs@Zn‐MOF‐74 coated electrode displayed a linear measurement range for glucose from 0.006 to 6 mM, with a detection limit of 1.8 μM (S/N: 3) and sensitivity of 64.51 μA mM^?1 cm^?2. The amperometric response of the enzyme biosensor demonstrated the typical behavior of Michaelis‐Menten kinetics. The obtained satisfying sensitivity and measurement range enabled fast and accurate glucose measurement in cherry juice using the fabricated biosensor. The water‐stable Zn‐MOF‐74 demonstrated higher enzyme loading capacity and can be potent supporting material for biosensor construction.     

Binder Free Modification of Glassy Carbon Electrode by Employing Reduced Graphene Oxide/ZnO Composite for Voltammetric Determination of Certain Nitroaromatics

Reduced Graphene oxide/ZnO nanoflowers ( rGO/ZnO‐NFs ) composite has been synthesized in‐situ using asymmetric Zn complex ( 1 ) as a single‐source molecular precursor (SSMP) with GO at 150 °C. The rGO/ZnO‐NFs composite was characterized by PXRD, UV‐vis, SEM, EDX mapping, TEM and SAED pattern to confirm its purity and morphology. The rGO/ZnO‐NFs composite shows uniform distribution of nanoflowers on graphene sheets. The modified glassy carbon electrode ( GCE ) was fabricated by drop wise layering of the rGO/ZnO‐NFs composite at the surface of the GCE without using binder. The binder free modified electrode ( GCE‐rGO/ZnO ) was explored for detection of nitroaromatics such as p‐nitro‐phenol ( p ‐NP ), 2,4‐dinitrophenol ( 2,4‐DNP ), 2,4‐dinitrotoluene ( 2,4‐DNT ) and 2,4,6‐trinitrophenol ( 2,4,6‐TNP ). The fabricated sensor showed remarkable response for the both toxicants and explosives. The LOD, sensitivity and linear range for the studied toxicants and explosives were found to be in a good range: p ‐NP= 0.93 μM, 240 μA mM⁻¹ cm⁻² and 0.2–0.9 mM; 2,4‐DNP= 6.2 μM, 203 μA mM⁻¹ cm⁻² and 0.1–0.9 mM; 2,4‐DNT= 10 μM, 371 μA mM⁻¹ cm⁻² and 0.2–0.9 mM; 2,4,6‐TNP= 16 μM, 514 μA mM⁻¹ cm⁻² and 0.2–0.9 mM, respectively.     

Tannic Acid Modified Electrochemical Biosensor for Glucose Sensing Based on Direct Electrochemistry

A novel glucose biosensor was constructed through the immobilization of glucose oxidase (GOx) on gold nanoparticles (Au NPs) deposited, and chemically reduced graphene oxide (rGO) nanocomposite. In the synthesis, tannic acid (TA) was used for the reduction of both graphene oxide, and Au³⁺ to rGO, and Au NPs, respectively. Also, by harnessing the π‐π interaction between graphene oxide and TA, and protein‐TA interaction, a novel nanocomposite for the fabrication of a third generation biosensor was successfully constructed. Upon the oxidation of TA to quinone, which is easily reducible at the negative potential range, enhanced electron transfer was obtained. The cyclic voltammetry (CV) results demonstrated a pair of well‐defined and quasi‐reversible redox peaks of active site molecule of GOx. The biosensor exhibited a linear response to glucose concentrations varying from 2 to 10 mM with a sensitivity of 18.73 mA mM⁻¹ cm⁻². The fabricated biosensor was used for the determination of glucose in beverages.     

Amperometric Glucose Biosensor Based on Electrochemically Deposited Gold Nanoparticles Covered by Polypyrrole

Graphite rod (GR) modified with electrochemicaly deposited gold nanoparticles (AuNPs) and adsorbed glucose oxidase (GOx) was used in amperometric glucose biosensor design. Enzymatic formation of polypyrrole (Ppy) on the surface of GOx/AuNPs/GR electrode was applied in order to improve analytical characteristics and stability of developed biosensor. The linear glucose detection range for Ppy/GOx/AuNPs/GR electrode was dependent on the duration of Ppy‐layer formation and the linear interval was extended up to 19.9 mmol L⁻¹ after 21 h lasting synthesis of Ppy. The sensitivity of the developed biosensor was determined as 21.7 μA mM⁻¹ cm⁻², the limit of detection – 0.20 mmol L⁻¹. Ppy/GOx/AuNPs/GR electrodes demonstrated advanced good stability (the t _1/2 was 9.8 days), quick detection of glucose (within 5 s) in the wide linear interval. Additionally, formed Ppy layer decreased the influence of electroactive species on the analytical signal. Developed biosensor is suitable for the determination of glucose in human serum samples.     

A Novel Amperometric Glucose Biosensor Based on Fe3O4-Chitosan-β-Cyclodextrin/MWCNTs Nanobiocomposite

A novel enzymatic biosensing platform toward glucose is achieved with nanocomposite of magnetic nanoparticles (Fe₃O₄−CS−CD) and multi-walled carbon nanotubes (MWCNTs). The synergistic effect of chitosan, β-cyclodextrin and MWCNTs can facilitate electron transfer between enzyme and electrode based on the promoting results of the cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS). The new biosensors exhibited direct electron transfer (DET) from enzyme to electrode after glucose oxidase (GOx) was immobilized on the modified electrode with the nanocomposite. Consequently, the enzymatic glucose biosensor displayed a considerably wide linear range (40 μM to 1.04 mM) with a high sensitivity of 23.59 μA mM⁻¹cm⁻², low detection limit of 19.30 μM, good selectivity, reproducibility and repeatability for detecting glucose. In addition, the current response still retained at 93.4 % after 25 days. Furthermore, the practical application of glucose biosensor was test in human serum samples with satisfactory accuracy, demonstrating promising and practical potential in biomedical diagnostics.     

Biosensor Based on Self‐Assembling Glucose Oxidase and Dendrimer‐Encapsulated Pt Nanoparticles on Carbon Nanotubes for Glucose Detection

A novel amperometric glucose biosensor based on layer‐by‐layer (LbL) electrostatic adsorption of glucose oxidase (GOx) and dendrimer‐encapsulated Pt nanoparticles (Pt‐DENs) on multiwalled carbon nanotubes (CNTs) was described. Anionic GOx was immobilized on the negatively charged CNTs surface by alternatively assembling a cationic Pt‐DENs layer and an anionic GOx layer. Transmission electron microscopy images and ζ‐potentials proved the formation of layer‐by‐layer nanostructures on carboxyl‐functionalized CNTs. LbL technique provided a favorable microenvironment to keep the bioactivity of GOx and prevent enzyme molecule leakage. The excellent electrocatalytic activity of CNTs and Pt‐DENs toward H₂O₂ and special three‐dimensional structure of the enzyme electrode resulted in good characteristics such as a low detection limit of 2.5 μM, a wide linear range of 5 μM–0.65 mM, a short response time (within 5 s), and high sensitivity (30.64 μA mM^?1 cm^?2) and stability (80% remains after 30 days).     

Enzyme Deposition by Polydimethylsiloxane Stamping for Biosensor Fabrication

High‐performance biosensors were fabricated by efficiently transferring enzyme onto Pt electrode surfaces using a polydimethylsiloxane (PDMS) stamp. Polypyrrole and Nafion were coated first on the electrode surface to act as permselective films for exclusion of both anionic and cationic electrooxidizable interfering compounds. A chitosan film then was electrochemically deposited to serve as an adhesive layer for enzyme immobilization. Glucose oxidase (GOx) was selected as a model enzyme for construction of a glucose biosensor, and a mixture of GOx and bovine serum albumin was stamped onto the chitosan‐coated surface and subsequently crosslinked using glutaraldehyde vapor. For the optimized fabrication process, the biosensor exhibited excellent performance characteristics including a linear range up to 2 mM with sensitivity of 29.4±1.3 μA mM⁻¹ cm⁻² and detection limit of 4.3±1.7 μM (S/N=3) as well as a rapid response time of ∼2 s. In comparison to those previously described, this glucose biosensor exhibits an excellent combination of high sensitivity, low detection limit, rapid response time, and good selectivity. Thus, these results support the use of PDMS stamping as an effective enzyme deposition method for electroenzymatic biosensor fabrication, which may prove especially useful for the deposition of enzyme at selected sites on microelectrode array microprobes of the kind used for neuroscience research in vivo .     

Development of a Glucose Biosensor Using Advanced Electrode Modified by Nanohybrid Composing Chemically Modified Graphene and Ionic Liquid

Nanohybrids of chemically modified graphene (CMG) and ionic liquid (IL) were prepared by sonication to modify the electrode. The modified CMG‐IL electrodes showed a higher current and smaller peak‐to‐peak potential separation than a bare electrode due to the promoted electron transfer rate. Furthermore, the glucose oxidase (GOx) immobilized on the modified electrode displayed direct electron transfer rate and symmetrical redox potentials with a linear relationship at different scan rates. The fabricated GOx/CMG‐IL electrodes were developed selective glucose biosensor with respect to a sensitivity of 0.64 μA mM^?1, detection limit of 0.376 mM, and response time of <5 s.     

Fabrication of Glucose Biosensor Based on Encapsulation of Glucose‐Oxidase on Sol‐Gel Composite at the Surface of Glassy Carbon Electrode Modified with Carbon Nanotubes and Celestine Blue

A simple procedure was developed to prepare a glassy carbon electrode modified with multi walled carbon nanotubes (MWCNTs) and Celestin blue. Cyclic voltammograms of the modified electrode show stable and a well defined redox couple with surface confined characteristic at wide pH range (2–12). The formal potential of redox couple (E′) shifts linearly toward the negative direction with increasing solution pH. The surface coverage of Celestine blue immobilized on CNTs glassy carbon electrode was approximately 1.95×10^?10 mol cm^?2. The charge transfer coefficient (α) and heterogeneous electron transfer rate constants (k_s) for GC/MWCNTs/Celestine blue were 0.43 and 1.26 s^?1, respectively. The modified electrode show strong catalytic effect for reduction of hydrogen peroxide and oxygen at reduced overpotential. The glucose biosensor was fabricated by covering a thin film of sol‐gel composite containing glucose oxides (GOx) on the surface of Celestine blue /MWCNTs modified GC electrode. The biosensor can be used successfully for selective detection of glucose based on the decreasing of cathodic peak current of oxygen. The detection limit, sensitivity and liner calibration rang were 0.3 μM, 18.3 μA/mM and 10 μM–6.0 mM, respectively. The accuracy of the biosensor for glucose detection was evaluated by detection of glucose in a serum sample, using standard addition protocol. In addition biosensor can reach 90% of steady currents in about 3.0 sec and interference effect of the electroactive existing species (ascorbic acid–uric acid and acetaminophen) was eliminated. Furthermore, the apparent Michaelis–Menten constant 2.4 mM, of GOx on the nano composite exhibits excellent bioelectrocatalytic activity of immobilized enzyme toward glucose oxidation. Excellent electrochemical reversibility of redox couple, high stability, technically simple and possibility of preparation at short period of time are of great advantages of this procedure for modification of glucose biosensor.     

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

A 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 (K_s) 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.     

An Amperometric Glucose Biosensor Based on Poly (Pyrrole‐2‐Carboxylic Acid)/Glucose Oxidase Biocomposite

A newly developed amperometric glucose biosensor based on graphite rod (GR) working electrode modified with biocomposite consisting of poly (pyrrole‐2‐carboxylic acid) (PCPy) particles and enzyme glucose oxidase (GOx) was investigated. The PCPy particles were synthesized by chemical oxidative polymerization technique using H₂O₂ as initiator of polymerization reaction and modified covalently with the GOx (PCPy‐GOx) after activation of carboxyl groups located on the particles surface with a mixture of N‐(3‐dimethylaminopropyl)‐N′‐ethylcarbodiimide hydrochloride (EDC) and N‐hydroxysuccinimide (NHS). Then the PCPy‐GOx biocomposite was dispersed in a buffer solution containing a certain amount of bovine serum albumin (BSA). The resulting biocomposite suspension was adsorbed the on GR electrode surface with subsequent solvent airing and chemical cross‐linking of the proteins with glutaraldehyde vapour (GR/PCPy‐GOx). It was determined that the current response of the GR/PCPy‐GOx electrodes to glucose measured at +300 mV vs Cl reference electrode was influenced by the duration of the PCPy particles synthesis, pH of the GOx solution used for the PCPy particles modification and the amount of immobilized PCPy‐GOx biocomposite. An optimal pH of buffer solution for operation of the biosensor was found to be 8.0. Detection limit was determined as 0.039 mmol L⁻¹ according signal to noise ratio (S/N: 3). The proposed glucose biosensor was tested in human serum samples.     

Fabrication of a Highly Sensitive Glucose Biosensor Based on Immobilization of Osmium Complex and Glucose Oxidase onto Carbon Nanotubes Modified Electrode

In this research a novel osmium complex was used as electrocatalyst for electroreduction of oxygen and H₂O₂ in physiological pH solutions. Electroless deposition at a short period of time (60 s), was used for strong and irreversible adsorption of 1,4,8,12‐tetraazacyclotetradecane osmium(III) chloride (Os(III)LCl₂) ClO₄ onto single‐walled carbon nanotubes (SWCNTs) modified GC electrode. The modified electrode shows a pair of well defined and reversible redox couple, Os(IV)/Os(III) at wide pH range (1–8). The glucose biosensor was fabricated by covering a thin film of glucose oxidase onto CNTs/Os‐complex modified electrode. The biosensor can be used successfully for selective detection of glucose based on the decreasing of cathodic peak current of oxygen. The fabricated biosensor shows high sensitivity, 826.3 nA μM^?1cm^?2, low detection limit, 56 nM, fast response time <3 s and wide calibration range 1.0 μM–1.0 mM. The biosensor has been successfully applied to determination of glucose in human plasma. Because of relative low applied potential, the interference from electroactive existing species was minimized, which improved the selectivity of the biosensor. The apparent Michaelis‐Menten constant of GOx on the nanocomposite, 0.91 mM, exhibits excellent bioelectrocatalytic activity of immobilized enzyme toward glucose oxidation. Excellent electrochemical reversibility, high stability, technically simple and possibility of preparation at short period of time are of great advantages of this glucose biosensor.     

Electrocatalytic Oxidation of Glucose by the Glucose Oxidase Immobilized in Graphene‐Au‐Nafion Biocomposite

Graphene was successfully prepared and well separated to individual sheets by introducing  SO₃⁻. XRD and TEM were employed to characterize the graphene. UV‐visible absorption spectra indicated that glucose oxidase (GOx) could keep bioactivity well in the graphene‐Au biocomposite. To construct a novel glucose biosensor, graphene, Au and GOx were co‐immobilized in Nafion to further modify a glassy carbon electrode (GCE). Electrochemical measurements were carried out to investigate the catalytic performance of the proposed biosensor. Cyclic voltammograms (CV) showed the biosensor had a typical catalytic oxidation response to glucose. At the applied potential +0.4 V, the biosensor responded rapidly upon the addition of glucose and reached the steady state current in 5 s, with the present of hydroquinone. The linear range is from 15 μM to 5.8 mM, with a detection limit 5 μM (based on the S/N=3). The Michaelis‐Menten constant was calculated to be 4.4 mM according to Lineweaver–Burk equation. In addition, the biosensor exhibits good reproducibility and long‐term stability. Such impressive properties could be ascribed to the synergistic effect of graphene‐Au integration and good biocompatibility of the hybrid material.     

The Hybrid of Gold Nanoparticles and 3D Flower‐like MnO2 Nanostructure with Enhanced Activity for Detection of Hydrogen Peroxide

3D Flower‐like manganese dioxide (MnO₂) nanostructure with the ability of catalysis for hydrogen peroxide (H₂O₂) and super large area that can support gold nanoparticles (AuNPs) with enhanced activity of electron transfer have been developed. The nanostructure of hybrids was prepared by directly mixing citric‐capped AuNPs and 3‐aminopropyltriethoxysilane (3‐APTES)‐capped nano‐MnO₂ using an electrostatic adsorption strategy. The Au‐MnO₂ composite was extensively characterized by scanning electron microscope (SEM), X‐ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), the Brunauer‐Emmett‐Teller (BET) method and X‐ray photoemission spectroscopy (XPS). Electrochemical properties were evaluated through cyclic voltammetry (CV) and amperometric method. The prepared sensor showed excellent electrochemical properties towards H₂O₂ with a wide linear range from 2.5×10⁻³∼1.39 mM and 3.89∼13.89 mM. The detection limit is 0.34 μM (S/N=3) with the sensitivities of 169.43 μA mM⁻¹ cm⁻² and 55.72 μA mM⁻¹ cm⁻². The detection of real samples was also studied. The result exhibited that the prepared sensor can be used for H₂O₂ detection in real samples.     

A Glucose Biosensor Based on Immobilization of Glucose Oxidase into 3D Macroporous TiO2

3D macroporous TiO₂ inverse opals have been derived from a sol‐gel procedure using polystyrene colloidal crystals as templates. EDS and SEM showed a face‐centered cubic (FCC) structure TiO₂ inverse opal was obtained. Glucose oxidase (GOx) was successfully immobilized on the surface of indium‐tin oxide (ITO) electrode modified by TiO₂ inverse opal (TiO_2(IO)). Electrochemical properties of GOx/TiO_2(IO)/ITO electrode were characterized by using the three electrodes system. The result of cyclic voltammetry showed that a couple of stable and well‐defined redox peaks for the direct electron transfer of GOx in absence of glucose, and the redox peak height enhanced in presence of 0.1 μM glucose. Compare with the ordinary structured GOx/TiO₂/ITO electrode, inverse opal structured GOx/TiO_2(IO)/ITO electrode has a better respond to the glucose concentration change. Under optimized experimental conditions of solution pH 6.8 and detection potential at 0.30 V versus saturated calomel electrode (SCE), amperometric measurements were performed. The sensitivity and the detection limit of glucose detection was 151 μA cm^?2 mM^?1 and 0.02 μM at a signal‐to‐noise ratio of 3, respectively. The good response was due to the good biocompatibility of TiO₂ and the large effective surface of the three‐dimensionally ordered macroporous structure.     

Direct Electrochemistry of Glucose Oxidase on Nail‐like Carbon and Its Biosensing for Glucose

Nail‐like carbon (NLC) was synthesized by a simple hydrothermal method. It was the first time that a novel electrochemical biosensing of glucose was explored based on the glucose oxidase (GOx)‐NLC‐chitosan (CHIT) glassy carbon electrode. Morphology and structure of NLC were characterized by scanning electron microscope; meanwhile the chemical composition was determined by X‐ray diffraction and energy dispersive X‐ray spectroscopy. The cyclic voltammetry of immobilized GOx showed a pair of quasireversible redox peaks with the formal potential (E°′) of ?0.458 V and the peak‐to‐peak potential separation was 47 mV at a scan rate of 100 mV s^?1. The present biosensor has a linear range of glucose from 0.02 to 1.84 mM (correlation coefficient of 0.9991) and detection limit of 0.01 mM (S/N=3). Compared with the previous reports based on the carbon material biosensor, it has a high sensitivity of 165.5 μA mM^?1 cm^?2 and low apparent Michaelis–Menten constant of 0.506 mM. Thus, the NLC may have potential applications in the field of bioelectrochemistry, bioelectronics and biofuels.     

Minimally‐invasive Microneedle‐based Biosensor Array for Simultaneous Lactate and Glucose Monitoring in Artificial Interstitial Fluid

Here we report the first mediated pain free microneedle‐based biosensor array for the continuous and simultaneous monitoring of lactate and glucose in artificial interstitial fluid (ISF). The gold surface of the microneedles has been modified by electrodeposition of Au‐multiwalled carbon nanotubes (MWCNTs) and successively by electropolymerization of the redox mediator, methylene blue (MB). Functionalization of the Au‐MWCNTs/polyMB platform with the lactate oxidase (LOX) enzyme (working electrode 1) and with the FAD‐Glucose dehydrogenase (FADGDH) enzyme (working electrode 2) enabled the continuous monitoring of lactate and glucose in the artificial ISF. The lactate biosensor exhibited a high sensitivity (797.4±38.1 μA cm^?2 mM^?1), a good linear range (10–100 μM) with a detection limit of 3 μM. The performance of the glucose biosensor were also good with a sensitivity of 405.2±24.1 μA cm^?2 mM^?1, a linear range between 0.05 and 5 mM and a detection limit of 7 μM. The biosensor array was tested to detect the amount of lactate generated after 100 minutes of cycling exercise (12 mM) and of glucose after a normal meal for a healthy patient (10 mM). The results reveal that the new microneedles‐based biosensor array seems to be a promising tool for the development of real‐time wearable devices with a variety of sport medicine and clinical care applications.     

Sulfonated polyaniline network grafted multi-wall carbon nanotubes for enzyme immobilization, direct electrochemistry and biosensing of glucose

A new nanomaterial was prepared by grafting a layer of sulfonated polyaniline network (SPAN-NW) on to the surface of multi-walled carbon nanotube (MWNT) and effectively utilized for immobilization of an enzyme and for the fabrication of a biosensor. SPAN-NW was formed on the surface of MWNT by polymerizing a mixture of diphenyl amine 4-sulfonic acid (DPASA), 4-vinyl aniline (VA) and 2-acrylamido-2-methyl-1-propane sulfonic acid (APASA) in the presence of amine functionalized MWNT (MWNT-NH₂). The MWNT-g-SPAN-NW was immobilized with glucose oxidase (GOx) to fabricate the SPAN-NW/GOx biosensor. MWNT-g-SPAN-NW/GOx electrode showed direct electron transfer (DET) for GOx with a fast heterogeneous electron transfer rate constant (k_s) of 4.11 s^− 1. The amperometric current response of MWNT-g-SPAN-NW/GOx biosensor shows linearity up to 9 mM of glucose, with a correlation coefficient of 0.99 and a detection limit of 0.11 μM (S/N = 3). At a low applied potential of − 0.1 V, MWNT-g-SPAN-NW/GOx electrode possesses high sensitivity (4.34 μA mM^− 1) and reproducibility towards glucose.     

Construction of a biointerface for glucose oxidase through diazonium chemistry and electrostatic self-assembly technique

In this study, a new procedure for the fabrication of biosensors was developed. The method is based on the covalent attachment of nitrophenyl groups to the electrode surface via diazonium salt reaction followed by their conversion to amine moieties through electrochemical reduction and electrostatic layer-by-layer (LbL) assembly technique. In this procedure, highly stable iron oxide (Fe₃O₄) nanoparticles (IONPs), chitosan (CHIt), GOx, and Nile blue (NB) were assembled on the surface of aminophenyl modified glassy carbon electrode (AP/GCE) by LbL assembly technique. Cyclic voltammetry (CV) and electrochemical impedance spectroscopy (EIS) were used to characterize the interfaces. The surface coverage of the active GOx and Michaelis–Menten constant (K _M) of the immobilized GOx were Γ?=?3.38?×?10^?11 mol cm^?2 and 2.54 mM, respectively. The developed biosensor displayed a well-defined amperometric response for glucose determination with high sensitivity (8.07 μA mM^?1) and low limit of detection (LOD) of 19.0 μM. The proposed approach allows simple biointerface regeneration by increasing pH which causes disruption of the ionic interactions and release of the electrostatic attached layers. The biosensor can then be reconstructed again using fresh enzyme. Simple preparation, good chemical and mechanical stabilities, and easy surface renewal are remarkable advantages of the proposed biosensor fabrication procedure.     

An enhanced Nonenzymatic Electrochemical Glucose Sensor Based on Copper‐Palladium Nanoparticles Modified Glassy Carbon Electrodes

Novel copper‐palladium nanoparticles modified glassy carbon electrodes (Cu−Pd/GC) with enhanced nonenzymatic sensing for glucose were facilely prepared by one‐step electrodeposition. The structure and composition of the prepared nanoparticles were characterized by XRD, SEM, TEM and EDS, respectively. The electrode modified process was characterized by electrochemical impedance spectroscopy. Cyclic voltammetry and chronoamperometric experiments were used to evaluate the electrocatalytic activities of the electrodes toward glucose. The surface morphology and the electrocatalytic activities of Cu−Pd/GC was compared to Pd and Cu nanoparticles modified glassy carbon electrodes (Pd/GC and Cu/GC), respectively. Thanks to homogeneous distribution of Cu−Pd nanoparticles and the synergistic effect of Cu and Pd atoms, Cu−Pd/GC exhibited the highest sensitivity (298 μA mM⁻¹ cm⁻²) and the widest linear amperometric response (0.01 mM to 9.6 mM, R²=0.996) toward glucose compared to Pd/GC and Cu/GC. The detection limit of Cu−Pd/GC was 0.32 μM (S/N=3). In addition, the as‐prepared Cu−Pd/GC glucose sensor also exhibited exceptional capabilities of anti‐interference, reproducibility and long‐term stability. The as‐prepared sensor was also evaluated for determination of glucose concentration in human blood serum samples, which exhibited high reliability and accuracy, having great potential in clinical application.