Search for: glucose-sensors
Total 21 records
M.Sc. Thesis Sharif University of Technology ; Dolati, Abolghasem
This research describes a new and relatively general method to grow well-aligned carbon nanotubes (CNTs) on cobalt-deposited stainless steel by thermal chemical vapor deposition (CVD) of ethylenediamine precursor. The CNTs are vertically aligned at high density over large areas on the surface. Different effective parameters in growth of carbon nanotubes, as type of substrate, surface treatment, temperature of growth , feeding carbon supplies have been studied. Finally, aligned carbon nanotubes have been prepared by 100-150 nm diameter and 9µ length. CoOx•nH2O–MWCNTs nanocomposites were successfully synthesized, using a cathodic electrochemical reduction of H2O2 to deposit cobalt...
Fabrication of Composite Electrode Materials Based on Bi-Metalic Metal-Organic Frameworks for Designation of Amperometric Non-Enzymatic Glucose Sensors, M.Sc. Thesis Sharif University of Technology ; Shahrokhian, Saeed
In the present study, the method of direct growth was used to grew bi-metalic MOFs based on cobalt and zinc, as electroactive centers, for preparing electrochemical sensors for the determination of glucose. In comparison to most of the electrochemical sensing platforms based on MOFs for determining glucose, which suffer from some disadvantages like time-consuming synthesis procedures and using hazardous organic solvents, the proposed in-situ growth method is much faster and without any need to toxic organic solvents. Herein, cobalt and zinc-based MOFs were grown on the surface of glassy carbon electrode by the direct and rapid conversion of layered double hydroxide nanosheets intermediates....
Development of a non-invasive micron sized blood glucose sensor based on microsphere stimulated raman spectroscopy, Article Sensors and Transducers ; Volume 147, Issue 12 , 2012 , Pages 129-142 ; 17265479 (ISSN) ; Jahangiri, N ; Taraz, M ; Sharif University of Technology
We proposed a new method for Non-invasive measuring of blood glucose levels by using micro sphere Stimulated Raman scattering. We show that this method can be used to measure biological glucose levels with low power lasers. The field enhancement due to the resonance condition of high quality factor microsphere causes to reduce stimulated Raman scattering thresholds of its surrounding media (glucose) and hence observing stimulated Raman scattering with low power. The results from theoretical studies indicate that the stimulated Raman signal amplitude levels produced from the very low Glucose concentrations. By measuring the changes of the signal intensity in output of fiber, we can determine...
Bimetallic CoZn-MOFs easily derived from CoZn-LDHs, as a suitable platform in fabrication of a non-enzymatic electrochemical sensor for detecting glucose in human fluids, Article Sensors and Actuators B: Chemical ; Volume 344 , 2021 ; 09254005 (ISSN) ; Shahrokhian, S ; Ezzati, M ; Sharif University of Technology
Elsevier B.V 2021
In the present study, an in-situ, two-step, highly controllable, fast, green, and facile strategy for fabricating the bimetallic cobalt-zinc-based metal-organic frameworks (MOFs) is employed for designing a non-enzymatic glucose sensing platform. The structural characterization, as well as the phase investigation of materials in each step, are assessed by X-ray diffraction, energy-dispersive X-ray spectroscopy, elemental mapping, field emission scanning electron microscopy, and Fourier transform infrared spectroscopy. Furthermore, the electrocatalytic activity of the CoZn-BTC/GC fabricated electrode toward the electro-oxidation of glucose is examined by various electrochemical techniques,...
Fabrication of a sensitive and fast response electrochemical glucose sensing platform based on co-based metal-organic frameworks obtained from rapid in situ conversion of electrodeposited cobalt hydroxide intermediates, Article Talanta ; Volume 210 , 2020 ; Ezzati, M ; Hosseini, H ; Sharif University of Technology
Elsevier B.V 2020
In this study, for the first time, we reported a fast and facile three-step in situ strategy for direct controllable growth of the Co3(BTC)2 MOFs thin films on the GCE, through the rapid conversion of the electrodeposited Co(OH)2 nano-flakes on rGO/GCE, to crystalline rectangular bar-shape structures of MOFs. X-ray diffraction spectroscopy, Fourier transform infrared spectroscopy, field emission scanning electron microscopy, energy dispersive X-ray spectroscopy and elemental mapping analysis used to the structural and morphological characterization of the well-synthesized MOFs. The as-prepared Co3(BTC)2 MOFs were used to construct a non-enzymatic sensing platform for determining the glucose...
Direct growth of metal-organic frameworks thin film arrays on glassy carbon electrode based on rapid conversion step mediated by copper clusters and hydroxide nanotubes for fabrication of a high performance non-enzymatic glucose sensing platform, Article Biosensors and Bioelectronics ; Volume 112 , 2018 , Pages 100-107 ; 09565663 (ISSN) ; Khaki Sanati, E ; Hosseini, H ; Sharif University of Technology
Elsevier Ltd 2018
The direct growth of self-supported metal-organic frameworks (MOFs) thin film can be considered as an effective strategy for fabrication of the advanced modified electrodes in sensors and biosensor applications. However, most of the fabricated MOFs-based sensors suffer from some drawbacks such as time consuming for synthesis of MOF and electrode making, need of a binder or an additive layer, need of expensive equipment and use of hazardous solvents. Here, a novel free-standing MOFs-based modified electrode was fabricated by the rapid direct growth of MOFs on the surface of the glassy carbon electrode (GCE). In this method, direct growth of MOFs was occurred by the formation of vertically...
Fabrication of a microdialysis-based nonenzymatic microfluidic sensor for regular glucose measurement, Article Sensors and Actuators, B: Chemical ; Volume 333 , 2021 ; 09254005 (ISSN) ; Saidi, M. S ; Shahrokhian, S ; Hosseini, H ; Kazemzadeh Hannani, S ; Sharif University of Technology
Elsevier B.V 2021
Microdialysis-based continuous glucose measuring systems are desirable candidates for accurate and biologically safe monitoring of glucose level in diabetic patients. However, it is necessary to improve these systems by utilizing highly reliable non-enzymatic sensors instead of enzymatic ones, while lowering the size and lessening the dialysis fluid consumption. Our purpose is to design an implantable integrated microfluidic device for regular nonenzymatic microdialysis-based glucose measurement. We report a novel nonenzymatic microfluidic glucose sensor based on Pt-Ni nanoparticles - multiwalled carbon nanotubes/screen-printed carbon electrode (Pt-Ni NPs-MWCNTs/SPE). Devised microfluidic...
Highly sensitive nonenzymetic glucose sensing platform based on MOF-derived NiCo LDH nanosheets/graphene nanoribbons composite, Article Journal of Electroanalytical Chemistry ; Volume 808 , 2018 , Pages 114-123 ; 15726657 (ISSN) ; Shahrokhian, S ; Iraji Zad, A ; Sharif University of Technology
Elsevier B.V 2018
Herein, a novel sensing platform based on NiCo layered double hydroxide (LDH) nanosheets/graphene nanoribbons (GNRs) modified glassy carbon electrode is presented for sensitive non-enzymetic determination of glucose. In the first step, nanoflower-like NiCo LDH nanosheets were grown on the surface of ZIF-67 dodecahedron nanocrystals which used as sacrificial template and were further characterized by means of scanning electron microscopy (SEM), transmission electron microscopy (TEM), energy dispersive X-ray spectroscopy (EDX), X-ray powder diffraction (XRD) and FTIR. In the next step, in order to fabricate a mechanically stable modified electrode, the as-prepared nanosheets were mixed with...
Electrodeposition and electrocatalytic properties of Pt/Ni-Co nanowires for non-enzymatic glucose detection, Article Journal of Alloys and Compounds ; Volume 554 , 2013 , Pages 169-176 ; 09258388 (ISSN) ; Mahshid, S ; Dolati, A ; Ghorbani, M ; Yang, L ; Luo, S ; Cai, Q ; Sharif University of Technology
A nanowire arrays system consisting of an ordered configuration of Pt, Ni and Co was constructed in single-bath solution through pulse electrodeposition. This structure was evaluated as a potential amperometric non-enzymatic sensor to detect glucose in alkaline solution. We observed a strong and fast amperometric response at low applied potential of 0.4 V vs. SCE over linear ranges of 0-0.2 mM and 0.2-8 mM glucose with sensitivities of 1125 and 333 μA mM-1 cm-2, respectively. We also observed a low detection limit for glucose of 1 μM. Correlation of the electronic and geometric modifications with the electrochemical performance characteristics enhanced catalytic activity of the electrode by...
A well-dispersed Pt/Ni/TiO 2 nanotubes modified electrode as an amperometric non-enzymatic glucose biosensor, Article Sensor Letters ; Volume 9, Issue 5 , October , 2011 , Pages 1598-1605 ; 1546198X (ISSN) ; Luo, S ; Yang, L ; Mahshid, S ; Dolati, A ; Ghorbani, M ; Cai, Q ; Sharif University of Technology
In this study a novel Pt/Ni nanostructure consisting of nano-bushes and nanocubes was fabricated onto TiO 2 nanotubes. The scanning electron microscopy images showed that a large amount of well-dispersed nano-architectures had uniformly covered all over the surface which made an electrode with high surface area. It was obviously seen that the nanocube structures mainly consists of Ni had been grown on top of each other while the Pt colonies represented bush-like structures. As a non-enzymatic glucose biosensor, the Pt/Ni TiO 2 nanotubes modified electrode exhibited an excellent performance. The proposed biosensor had two linear ranges for detection of glucose from 0 to 0.12 mM (correlation...
Effect of formulation factors on the bioactivity of glucose oxidase encapsulated chitosan-alginate microspheres: In vitro investigation and mathematical model prediction, Article Chemical Engineering Science ; Volume 125 , March , 2015 , Pages 4-12 ; 00092509 (ISSN) ; Cheng, J ; Wu, X. Y ; Sharif University of Technology
Elsevier Ltd 2015
Higher reactive oxygen species (ROS) levels in cancer cells than normal cells have long been recognized, which makes cancer cells more susceptible to excess ROS. Thus oxidation (also called pro-oxidant) therapy has been explored as new cancer therapy regimens. To produce additional ROS, e.g. H2O2 in situ within tumor, we encapsulated glucose oxidase in chitosan-coated alginate-calcium microspheres (GOX-MS) for locoregional treatment and demonstrated its efficacy against cancer cells in vitro and in vivo. Owing to the complex biological functions of ROS, the production rate and amount of H2O2 are critical to achieve therapeutic benefits without causing normal tissue toxicity. This work was...
Hierarchical core-shell structure of ZnO nanotube/MnO2 nanosheet arrays on a 3D graphene network as a high performance biosensing platform, Article RSC Advances ; Volume 6, Issue 66 , 2016 , Pages 61190-61199 ; 20462069 (ISSN) ; Shahrokhian, S ; Iraji zad, A ; Sharif University of Technology
Royal Society of Chemistry
A hierarchical core-shell structure composed of ZnO nanotubes/MnO2 nanosheets was fabricated via a two-step electrochemical deposition procedure on the surface of a 3D graphene network (3DGN) as a free-standing monolithic electrode. In the first step, ZnO nanorod arrays were grown on the surface of a 3DGN followed by electrochemical deposition of MnO2 nanosheets in the next step, which caused the inner parts of initial ZnO nanorods to etch away and resulted in the formation of ZnO nanotubes (ZnO NTs). The highly porous interconnected graphene backbone offers very high conductivity and a large accessible surface area. On the other hand, the formation of ZnO nanotubes can enhance the...
Three-dimensional hybrid graphene/nickel electrodes on zinc oxide nanorod arrays as non-enzymatic glucose biosensors, Article Sensors and Actuators, B: Chemical ; Volume 251 , 2017 , Pages 462-471 ; 09254005 (ISSN) ; Aashuri, H ; Simchi, A ; Sharif University of Technology
Elsevier B.V 2017
We present a novel hybrid electrode based on reduced graphene oxide/nickel/zinc oxide heterostructures. The sensor was fabricated by template-free hydrothermal growth of ZnO nanorod arrays on conductive glass substrates (FTO) followed by conformal electrodeposition of nickel nanoparticles with an average size of 18 nm. Then, in-situ reduction and electrophoretic deposition of graphene oxide (GO) nanosheets on the structured ZnO/Ni electrode was performed. The prepared three-dimensional nanostructure exhibited fast electrocatalytic response (<3 s) towards glucose oxidation due to the large surface area and high electro-activity. The prepared biosensor possessed a wide linear range over...
Advanced on-site glucose sensing platform based on a new architecture of free-standing hollow Cu(OH)2 nanotubes decorated with CoNi-LDH nanosheets on graphite screen-printed electrode, Article Nanoscale ; Volume 11, Issue 26 , 2019 , Pages 12655-12671 ; 20403364 (ISSN) ; Khaki Sanati, E ; Hosseini, H ; Sharif University of Technology
Royal Society of Chemistry 2019
The planned design of nanocomposites combined with manageable production processes, which can offer controllability over the nanomaterial structure, promises the practical applications of functional nanomaterials. Hollow core-shell nanostructure architectures represent an emerging category of advanced functional nanomaterials, whose benefits derived from their notable properties may be hampered by complicated construction processes, especially in the sensing domain. In this regard, we designed a highly porous three-dimensional array of hierarchical hetero Cu(OH)2@CoNi-LDH core-shell nanotubes via a quick, very simple, green, and highly controllable three-step in situ method; they were...
Influence of phosphate anions on the stability of immobilized enzymes. Effect of enzyme nature, immobilization protocol and inactivation conditions, Article Process Biochemistry ; Volume 95 , August , 2020 , Pages 288-296 ; Carballares, D ; Morellon Sterling, R ; Siar, E. H ; Kashefi, S ; Chafiaa, M ; Arana Peña, S ; Rios, N. S ; Gonçalves, L. R. B ; Fernandez Lafuente, R ; Sharif University of Technology
Elsevier Ltd 2020
A destabilizing effect at pH 7 of sodium phosphate on several lipases immobilized via interfacial activation is shown in this work. This paper investigates if this destabilizing effect is extended to other inactivation conditions, immobilization protocols or even other immobilized enzymes (ficin, trypsin, β-galactosidase, β-glucosidase, laccase, glucose oxidase and catalase). As lipases, those from Candida antarctica (A and B), Candida rugosa and Rhizomucor miehei have been used. Results confirm the very negative effect of 100 mM sodium phosphate at pH 7.0 for the stability of all studied lipases immobilized on octyl agarose, while using glutaraldehyde-support the effect is smaller (still...
Delay-Independent regulation of blood glucose for type-1 diabetes mellitus patients via an observer-based predictor feedback approach by considering quantization constraints, Article European Journal of Control ; Volume 63 , January , 2021 , Pages 240-252 ; 09473580 (ISSN) ; Tavazoei, M. S ; Sharif University of Technology
Elsevier Ltd 2021
Diabetes, as a widespread chronic disease, is caused by the increase of blood glucose concentration (BGC) due to pancreatic insulin production failure and/or insulin resistance in the body. The artificial pancreas (AP) known as a closed-loop insulin delivery control system consists of a glucose sensor for BGC measurement, a control algorithm for calculation of exogenous insulin delivery rate (IDR), and an insulin infusion pump. The AP provides a closed-loop glucose-insulin regulatory system for type-1 diabetes mellitus (T1DM) patients in order to effectively reduce the high BGC level. In this paper, we aim to design a controller in order to regulate the BGC of T1DM patients at its basal...
Ionic liquid/graphene oxide as a nanocomposite for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase, Article Journal of Solid State Electrochemistry ; Volume 17, Issue 1 , January , 2013 , Pages 183-189 ; 14328488 (ISSN) ; Ghasemi, S ; Ghourchian, H ; Gholami, M. R ; Sharif University of Technology
By combination of 1-ethyl-3-methyl immidazolium ethyl sulfate as a typical room temperature ionic liquid (IL) and graphene oxide (GO) nanosheets, a nanocomposite was introduced for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase (GOx). The enzyme on the IL-GO-modified glassy carbon electrode exhibited a quasireversible cyclic voltammogram corresponding to the flavine adenine dinucleotide/FADH2 redox prosthetic group of GOx. At the scan rate of 100 mV s-1, the enzyme showed a peak-to-peak potential separation of 82 mV and the formal potential of -463 mV (vs Ag/AgCl in 0.1 M phosphate buffer solution, pH 7.0). The kinetic parameters of the charge transfer...
Article Sensors and Actuators, B: Chemical ; Volume 158, Issue 1 , November , 2011 , Pages 185-189 ; 09254005 (ISSN) ; Hormozi Nezhad, M. R ; Khodaveisi, J ; Dashti, R ; Sharif University of Technology
A novel glucose biosensor based on chromophore (silver nanoparticles) decolorizing for the photometric determination of glucose was developed. Silver nanoparticles are directly synthesized in the sol-gel matrix by a one-step method based on the reduction of the inorganic precursor AgNO3 and were used for the preparation, characterization and calibration of a highly sensitive and cost-effective localized surface plasmon resonance-based glucose biosensor. In the presence of glucose oxidase (GOx) and due to the enzyme-substrate (glucose) reaction, H2O2 was produced and silver nanoparticles in the sol-gel glass have the ability for the decomposition of hydrogen peroxide. Due to the degradation...
Amine functionalized TiO2 coated on carbon nanotube as a nanomaterial for direct electrochemistry of glucose oxidase and glucose biosensing, Article Journal of Molecular Catalysis B: Enzymatic ; Volume 68, Issue 2 , 2011 , Pages 206-210 ; 13811177 (ISSN) ; Rafiee Pour, H. A ; Ghourchian, H ; Gholami, M. R ; Sharif University of Technology
A nano-composite material consisting of amine functionalized TiO 2-coated carbon nanotubes was prepared and used for glucose oxidase (GOx) absorption. The GOx bearing nanomaterial was fixed on a glassy carbon electrode to construct a novel biosensor for glucose determination. The direct electrochemistry of immobilized GOx and its electron transfer parameters at the modified glassy carbon electrode were reported. The apparent heterogeneous electron transfer rate constant (ks) of GOx was estimated to be 3.5 s-1, which is higher than those reported previously. Amperometric detection of glucose resulted in a rapid (3 s) and stable response in the linear concentration range from 1.8 to 266 μM....
Article Journal of Membrane Science ; Volume 335, Issue 1-2 , 2009 , Pages 21-31 ; 03767388 (ISSN) ; Wu, X. Y ; Sharif University of Technology
A theoretical model was developed to describe a dynamic process involving an enzymatic reaction and diffusion of reactants and product inside glucose sensitive composite membrane. The composite membrane consisted of nanoparticles of a weakly acidic polymer, glucose oxidase and catalase embedded in a hydrophobic polymer. Time- and position-dependent diffusivity of involved species was considered in the model. Donnan equilibrium was used to find concentrations of buffer ions inside the membrane. The profiles of pH, species concentrations, volume fraction of swollen gel, polymer and water-filled space, as well as solute diffusivity inside the membrane were predicted by the model as a function...