Search for: glucose
Total 122 records
Determination of heavy metal ions by an amperometric biosensor based on glucose oxidase immobilized onto single-walled carbon nanotubes/Nile blue nanocomposite, Article Journal of the Iranian Chemical Society ; Volume 15, Issue 8 , 2018 , Pages 1765-1774 ; 1735207X (ISSN) ; Sabzi, R. E ; Borghei, S. M ; Sharif University of Technology
Springer Verlag 2018
An enzymatic electrochemical biosensor was prepared based on glucose oxidase (GOD) immobilized on single-walled carbon nanotubes/Nile blue (Nb–SWCNTs) nanocomposite cross-linked with glutaraldehyde on graphite electrode. The function of glucose biosensor is based on the electrocatalytic reduction of H2O2 generated by the reaction of the enzyme with glucose molecules. The biosensor was characterized by Fourier transform infrared (FTIR) spectroscopy, emission scanning (FESEM), UV–Vis spectrometry, and voltammetric and amperometric methods. Parameters influencing the performance of the biosensor, namely pH and applied potential, were optimized. Inhibition was carried out for the detection of...
Conformational study of anomeric center in some carbohydrate derivatives, Article Journal of Molecular Structure: THEOCHEM ; Volume 814, Issue 1-3 , 2007 , Pages 127-130 ; 01661280 (ISSN) ; Ghiasi, M ; Sharif University of Technology
Density functional theory (DFT) using the B3LYP functional and the split-valance 6-311++G** basis sets have been used to investigate the structures of 24 derivatives of glucose and galactose which present sequences of atoms in anomeric configurations of the C-C bond in C-glycosides, C-O bond in glycosides, C-S bond in thioglycosides, C-N bond in glycosylamines, and C-F/Cl bond in glycosyl halides. Values of the vicinal coupling constants, 3JCXCH (X = C, O, S), for mentioned compounds were calculated in water and methanol solvents by using PCM method and new Karplus equations were derived. © 2007 Elsevier B.V. All rights reserved
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...
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...
Ionic liquid/graphene oxide as a nanocomposite for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase, Article Journal of Solid State Electrochemistry ; Vol. 17, Issue 1 , January , 2013 , pp 183-189 ; ISSN: 1432-8488 ; Ghasemi, S. (Shahnaz) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; 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...
Morphology control in oxygen-rich nanotubular titania for enzyme-free glucose detection, Article Surfaces and Interfaces ; 2021 ; 24680230 (ISSN) ; Naseri, N ; Sharif University of Technology
Elsevier B.V 2021
The necessity of research in food and nutrition and the emergence of diabetes mellitus call for fast and efficient glucose detection. Here, series of highly sensitive non-enzymatic photoelectrochemical glucose sensor based on engineered titanium dioxide nanotube arrays has been synthesized using a simple electrochemical approach to tune nanotubes morphology in a way that the highest sensitivity factor (525.5 µAmM−1cm−2) and saturation concentrations (0.18 mM) achieved in the photoelectrochemical sensor. The formation of oxygen-rich titanium oxide was confirmed by several techniques. Dependent on the growth condition, nanotube length changed from 1.9 to 8.4 µm while their inner diameter...
Surfactant production by an enzymatic method, Article Enzyme and Microbial Technology ; Volume 33, Issue 1 , 2003 , Pages 33-37 ; 01410229 (ISSN) ; Alemzadeh, I ; Sharif University of Technology
Elsevier Inc 2003
Glucose was acylated with palmitic acid using two kinds of lipases. The reactions were performed in the presence of an organic solvent. Solvent effect and molecular sieve effect and also the effect of enzyme amount and influence of molar ratio of substrates on glucose palmitate production with lipase from Rhizomucor miehei (Palatase® M) were studied. Application of molecular sieves together with open system increased palmitic acid conversion in the reaction mixture. Glucose palmitate was obtained in 41.18% conversion in hexane at 40°C with Palatase® M. Glucose palmitate was also synthesized with lipase from Candida antarctica (Novozyme 435). Esterification of palmitic acid with glucose...
Novel type of two-impinging-jets reactor for solid-liquid enzyme reactions, Article AIChE Journal ; Volume 52, Issue 2 , 2006 , Pages 692-704 ; 00011541 (ISSN) ; Sharif University of Technology
The isomerization of D-glucose to D-fructose using the immobilized glucose isomerase, as a typical model system of solid-liquid enzyme reactions has been carried out in a novel type of two-impinging-jets reactor (TIJR), which is characterized by a rotating inner cylinder in a stationary one. Because of the impinging process, turbulence, and complex trajectory of the solid particles within the reactor, the fractional conversion of glucose obtained in the TIJR increased dramatically compared to that obtained by conventional reaction systems. A compartment model was considered to describe the pattern of flow [residence time distribution (RTD) of solid particles] within the TIJR. Considering...
Embryonic stem cells maintain an undifferentiated state on dendrimer-immobilized surface with D-glucose display, Article Polymers ; Volume 3, Issue 4 , 2011 , Pages 2078-2087 ; 20734360 (ISSN) ; Kim, M. H ; Kino Oka, M ; Miyazaki, J. I ; Taya, M ; Sharif University of Technology
In serial passaging cultures of mouse embryonic stem (ES) cells, we employed a dendrimer-immobilized substrate that displayed D-glucose as a terminal ligand. The D-glucose-displaying dendrimer (GLU/D) surface caused the ES cells to form loosely attached spherical colonies, while those on a gelatin-coated surface formed flatter colonies that were firmly attached to the surface. Despite the morphological similarities between the colonies on the GLU/D surface and aggregates on a conventional bacteriological dish, immunostaining and RT-PCR analyses revealed the maintenance of cells within the spherical colonies on the GLU/D surface in an undifferentiated state with very low expressions of...
Kinetics of glucose isomerization to fructose by immobilized glucose isomerase (Sweetzyme IT), Article Industrial and Engineering Chemistry Research ; Volume 48, Issue 7 , 2009 , Pages 3271-3278 ; 08885885 (ISSN) ; Shoai Tehrany, M ; Safari, I ; Sharif University of Technology
We present the kinetic parameters and equilibrium constant of the enzymatic glucose-fructose isomerization reaction with an immobilized glucose isomerase (IGI), Sweetzyme IT, using a batch stirred-tank reactor following the procedure developed by Dehkordi et al. (AIChE J. 2008, 54, 1333). The model predictions were compared with the experimental data and fair agreements were found. The influence of temperature on the equilibrium constant and kinetic parameters of glucose to fructose isomerization reaction was investigated. In addition, the frequency factors and the activation energies were determined by using Arrhenius-like expressions. Furthermore, correlations were found for the maximum...
Experimental and modeling study of catalytic reaction of glucose isomerization: Kinetics and packed-bed dynamic modeling, Article AIChE Journal ; Volume 54, Issue 5 , 2008 , Pages 1333-1343 ; 00011541 (ISSN) ; Safari, I ; Karima, M. M ; Sharif University of Technology
The kinetics and equilibrium of isomerization reaction of D-glucose to D-fructose have been investigated using a commercial immobilized glucose isomer ase (IGI), Sweetzyme type IT®, in a batch stirred-tank reactor. The batch experimental data were used to model the reaction kinetics using the well-known Michaelis-Menten rate expression. The kinetic model was utilized in a dynamic-mathematical model for a packed-bed reactor to predict the concentration profiles of D-glucose and D-fructose within the reactor. The experimental results for the fractional conversion of D-glucose in the packed-bed reactor of IGI catalyst indicated that the model prediction of the transient and steady-state...
CNT Modified Coatings for Glucose Sensing, 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...
Optimization of biomass and biokinetic constant in Mazut biodegradation by indigenous bacteria BBRC10061, Article Journal of Environmental Health Science and Engineering ; Vol. 12, issue. 1 , June , 2014 ; Mashreghi, M ; Yaghmaei, S ; Sharif University of Technology
Optimization based on appropriate parameters can be applied to improve a process. Mazut degradation as a critical issue in environment requires optimization to be efficiently done. To provide biodegradation conditions, experiments were designed on the least interactions among levels of parameters consisting of pH, Tween 80, glucose, phosphorous source, nitrogen source, and time. Kinetic constants and biomass were calculated based on 16 assays, designed using Taguchi method, which constructed various mazut biodegradation conditions. Kinetics of mazut degradation by newly isolated bacteria Enterobacter cloacae closely followed second order kinetic model. Results of the 16 experiments showed...
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...
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...
Optimizing fuzzy logic controller for diabetes type I by genetic algorithm, Article 2010 The 2nd International Conference on Computer and Automation Engineering, ICCAE 2010, 26 February 2010 through 28 February 2010, Singapore ; Volume 2 , 2010 , Pages 4-8 ; 9781424455850 (ISBN) ; Azizi, A ; Sharif University of Technology
Biological systems are highly nonlinear, and there is a significant amount of variability from one patient to another. A controller for drug infusion has to be able to achieve good performance for most of the potential patient population. These controllers are designed for the general population, as no knowledge is available before hand for each particular patient. This necessitates perforce an algorithm that will be able to compensate for the differences between individuals and external factors. Of the possibilities, fuzzy logic direct model reference adaptive control (DMRAC) is the choice for Insulin infusion control for diabetes type I as results presented herein. Safety and robustness...
Enzymatic biosensing by covalent conjugation of enzymes to 3D-networks of graphene nanosheets on arrays of vertically aligned gold nanorods: application to voltammetric glucose sensing, Article Microchimica Acta ; Volume 185, Issue 3 , 2018 ; 00263672 (ISSN) ; Simchi, A ; Aashuri, H ; Sharif University of Technology
Springer-Verlag Wien 2018
The authors demonstrate efficient direct electron transfer from the enzyme glucose oxidase to vertically aligned gold nanorods with a diameter of ~160 nm and a length of ~2 μm that are covalently linkage to a 3-dimensional network of reduced graphene oxide nanosheets. The assembly can be prepared by a 2-step electrochemical procedure. This hybrid structure holds the enzyme in a favorable position while retaining its functionality that ultimately provides enhanced performance for enzymatic sensing of glucose without utilizing mediators. The nanorod assembly was applied to the voltammetric detection of glucose. Figures of merit include an electrochemical sensitivity of 12 μA·mM−1·cm−2...
Study on commercial membranes and sweeping gas membrane distillation for concentrating of glucose syrup, Article Journal of Membrane Science and Research ; Volume 6, Issue 1 , 2020 , Pages 47-57 ; Kargari, A ; Bastani, D ; Soleimani, M ; Fatehi, L ; Sharif University of Technology
Amirkabir University of Technology - Membrane Processes Research Laboratory 2020
In this work, sweeping gas membrane distillation (SGMD) process was used for concentrating of glucose syrup. The main questions in this work include: is SGMD process practical for concentrating of glucose solution prior the fermentation step in bioethanol process?. and are the commercially available hydrophobic membranes sufficient enough to develop the SGMD process in pilot scale for this issue?. To answer these questions, SGMD process was performed using three commercial membranes made of PP, PVDF and PTFE. All membranes characterized using scanning electron and atomic force microscopes for their morphological and topographical features. Important operating parameters including feed...
Facile preparation of a highly sensitive non-enzymatic glucose sensor based on the composite of Cu(OH)2 nanotubes arrays and conductive polypyrrole, Article Microchemical Journal ; Volume 169 , 2021 ; 0026265X (ISSN) ; Shahrokhian, S ; Hafezi Kahnamouei, M ; Sharif University of Technology
Elsevier Inc 2021
A novel amperometric non-enzymatic glucose sensor is designed by the facile preparation method. It is made by electrodeposition of Cu clusters and converting them to Cu(OH)2 nanotubes (Cu(OH)2NTs) arrays along with thin-film electro-polymerized of spindle-shaped polypyrrole (PPy@Cu(OH)2NTs), which have been doped by using sodium Benzene-1,3-disulfonate as an anion dopant. Various electrochemical methods investigate the electrochemical performance of the modified electrode toward glucose detection. Under the optimized conditions, a significant electrochemical response improvement is observed toward the electro-oxidation of glucose on the PPy@Cu(OH)2NTs electrode's surface relative to the...
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,...