Search for: phosphate-buffers
Total 22 records
Cell life cycle effects of bare and coated superparamagnetic iron oxide nanoparticles, Article Toxic Effects of Nanomaterials ; 2012 , Pages 53-66 ; 9781608054213 (ISBN) ; Laurent, S ; Journeay, W. S ; Sharif University of Technology
Due to the hopeful potential of nanoparticles in medicine, they have attracted much attention for various applications such as targeted drug/gene delivery, separation or imaging. Interaction of NPs with the biological environment can lead to a wide range of cellular responses. In order to have safe NPs for biomedical applications, the current biocompatibility researches are particularly focused on the severe toxic mechanisms which cause cells death. These mechanisms are apoptosis, autophagy and necrosis, which can also be intricately linked with the cell-life cycle, as there are various check-points and controls in a cell's life cycle to ensure appropriate division processes. Mechanisms by...
Loading drug on nanostructured Ti6Al4V-HA for implant applications, Article International Journal of Engineering, Transactions B: Applications ; Volume 31, Issue 8 , 2018 , Pages 1159-1165 ; 1728144X (ISSN) ; Sadrnezhaad, S. K ; Sharif University of Technology
Materials and Energy Research Center 2018
Arrayed Ti6Al4V nanotubes (TNT) coated with hydroxyapatite (HA) were synthesized via electrochemical anodization method. Paracetamol was loaded onto TNT-HA electrode. Effects of anodization, nanotube formation and hydroxyapatite deposition on sorption and release of the drug were investigated. Saturation time of paracetamol on the anodized samples was 30% shorter than the hydroxyapatite-coated samples. Release behavior of the loaded drug was studied by (a) plunging the probe into phosphate buffered saline (PBS), (b) sampling the drug-loaded PBS at different times and (c) analyzing the solution via ultraviolet-visible (UV-vis) spectroscopy. Results showed that HA electrodes hold higher...
Evaluation of bio-compatible poly(ethylene glycol)-based solid-phase microextraction fiber for in vivo pharmacokinetic studies of diazepam in dogs, Article Analyst ; Volume 132, Issue 7 , 2007 , Pages 672-678 ; 00032654 (ISSN) ; Zhang, X ; Musteata, F. M ; Bagheri, H ; Pawliszyn, J ; Sharif University of Technology
Royal Society of Chemistry 2007
Solid-phase microextraction probes based on poly(ethylene glycol)/C18-bonded silica were used for in vivo monitoring of drugs from circulating blood of beagles, over a period of 8 h. After sampling, the extracted drugs were subsequently quantified by liquid chromatography coupled with tandem mass spectrometry. External calibrations in whole blood and phosphate-buffered saline were used to correlate the amount of analytes extracted in regard to the total and free concentrations in blood respectively. The probe provided sufficient sensitivity for the drugs in the blood matrix, while the need for drawing blood was eliminated. The limit of detections of the method from whole blood were 1.7, 1.4...
Magnetic hyperthermia behaviour of Co and reduced GO nanocomposites, Article Micro and Nano Letters ; Volume 15, Issue 4 , April , 2020 , Pages 239-244 ; Sadrnezhaad, S. K ; Sharif University of Technology
Institution of Engineering and Technology 2020
Co-precipitation of CoCl2.6H2O with graphene oxide (GO) and heating at 400°C for 4 h under hydrogen resulted in the construction of cobalt/ reduced GO (Co/rGO) nanocomposite utilisable in magnetic thermal therapy. Field emission scanning electron microscopy, transmission electron microscopy, X-ray photoelectron spectroscopy, vibrating sample magnetometry, thermogravimetric analysis/derivative thermogravimetry, and X-ray diffraction methods characterised the samples. Time-temperature curves of the samples containing 30, 50, 70, and 100 µg ml−1 Co/rGO nanoparticles (NPs) suspended in phosphate-buffered saline were determined at different specific heating rates. Magnetic-field response of...
A novel pathway to produce biodegradable and bioactive PLGA/TiO2 nanocomposite scaffolds for tissue engineering: Air–liquid foaming, Article Journal of Biomedical Materials Research - Part A ; Volume 108, Issue 6 , 2020 , Pages 1390-1407 ; Madaah Hosseini, H. R ; Samadikuchaksaraei, A ; Sharif University of Technology
John Wiley and Sons Inc 2020
Poly (lactate-co-glycolate) (PLGA) is a typical biocompatible and biodegradable synthetic polymer. The addition of TiO2 nanoparticles has shown to improve compressive modulus of PLGA scaffolds and reduced fast degradation. A novel method has been applied to fabricate PLGA/TiO2 scaffolds without using any inorganic solvent, with aim of improving the biocompatibility, macroscale morphology, and well inter-connected pores efficacy: Air–Liquid Foaming. Field Emission Scanning Electron Microscopy (FESEM) revealed an increase in interconnected porosity of up to 98%. As well the compressive testing showed enhancement in modulus. Bioactivity and in vitro degradation were studied with immersion of...
Evaluating the effect of ultrasmall superparamagnetic iron oxide nanoparticles for a long-term magnetic cell labeling, Article Journal of Medical Physics ; Volume 38, Issue 1 , 2013 , Pages 34-40 ; 09716203 (ISSN) ; Oghabian, M. A ; Allen, B. J ; Amanlou, M ; Masoudi, A ; Daha, F. J ; Sharif University of Technology
In order to evaluate the long-term viability, the iron content stability, and the labeling efficiency of mammalian cells using magnetic cell labeling; dextran-coated ultrasmall superparamagnetic iron oxide (USPIOs) nanoparticles with plain surfaces having a hydrodynamic size of 25 nm were used for this study. Tests were carried out in four groups each containing 5 flasks of 5.5 × 10 6 AD-293 embryonic kidney cells. The cell lines were incubated for 24 h using four different iron concentrations with and without protamine sulfate (Pro), washed with phosphate-buffered saline (PBS) and centrifuged three times to remove the unbounded USPIOs. Cell viability was also verified using USPIOs. There...
Catalytic activity of TiO 2 nanotubes modified with carbon and Pt nanoparticles for detection of dopamine, Article ECS Transactions ; Volume 35, Issue 35 , 2011 , Pages 53-62 ; 19385862 (ISSN) ; 9781607682950 (ISBN) ; Mahshid, S. S ; Ghahremaninezhad, A ; Askari, M ; Dolati, A ; Yang, L ; Luo, Sh ; Cai, Q ; Sensor; Organic and Biological Electrochemistry ; Sharif University of Technology
Catalytic activity of carbon/Pt nanoparticles modified TiO 2 nanotubes electrode was studied by using dopamine contained solutions. The TiO 2 nanotubes electrode was prepared using anodizing method in aqueous solution. The electrochemical pulse method was then applied for electrodeposition of Pt nanoparticles onto the TiO 2 nanotubes. Further modification was achieved by decomposition of polyethylene glycol in a tube furnace to have a carbon/Pt nanoparticles modified TiO 2 nanotubes electrode. The final modified electrode could successfully detect the electro-oxidation of dopamine in a ImM contained solution using cyclic voltametry method. Also, a high sensitivity towards the oxidation of...
Kinetic study and growth behavior of template-based electrodeposited platinum nanotubes controlled by overpotential, Article Materials Chemistry and Physics ; Volume 187 , 2017 , Pages 141-148 ; 02540584 (ISSN) ; Dolati, A ; Imanieh, I ; Yashiro, H ; Kure-Chu, S. Z ; Sharif University of Technology
Elsevier Ltd 2017
Platinum nanotubes (PtNTs) are fabricated by potentiostatic electrodeposition at various overpotentials (−200 up to −400 mV versus SCE) in polycarbonate templates (PCTs) with pore diameter of 200 nm in a solution containing 5 mM H2PtCl6 and 0.1 M H2SO4. The synthesized PtNTs are characterized by field emission scanning electron microscopy (FE-SEM), and transmission electron microscopy (TEM). The electrochemical growth mechanism within nanoscopic pores and the relationship between morphological variations and kinetic parameters are investigated for the first time. It is shown that more porous structure of nanotubes forms at high overpotentials possibly due to preferably nucleation. The...
Design and fabrication of a novel microfluidic system for enrichment of circulating tumor cells with the assistance of computer simulations, Article Avicenna Journal of Medical Biotechnology ; Volume 11, Issue 4 , 2019 , Pages 277-284 ; 20082835 (ISSN) ; Vossoughi, M ; Alemzadeh, I ; Sharif University of Technology
Avicenna Research Institute 2019
Background: Cancer is the first cause of death in developed countries. The heterogeneous nature of cancer requires patient-specified treatment plans. One reliable approach is collecting Circulating Tumour Cells (CTCs) and using them for prognosis and drug response assessment purposes. CTCs are rare and their separation from normal cell requires high-accuracy methods. Methods: A microfluidic cell capture device to separate CTCs from peripheral blood is presented in this study. The CTC separation device applies hydrodynamic forces to categorize cells according to their sizes. The proposed device is designed and evaluated by numerical simulations and validated experimentally. The simulation...
Glucose cross-linked hydrogels conjugate HA nanorods as bone scaffolds: Green synthesis, characterization and in vitro studies, Article Materials Chemistry and Physics ; Volume 242 , 2020 ; Shafiei, N ; Mohandes, F ; Dolatyar, B ; Zandi, N ; Zeynali, B ; Simchi, A ; Sharif University of Technology
Elsevier Ltd 2020
In the expanding field of tissue engineering (TE), improvement of biodegradability and osteoconductivity of biomaterials are required. The use of non-toxic reagents during manufacturing processes is also necessary to decrease toxicity and increase cell viability in vivo. Herein, we present a novel approach to prepare hydroxyapatite (HA) nanorods from sea bio-wastes through a green and eco-friendly wet-chemical processing for bone TE. Highly porous natural polymer-ceramic nanocomposites made of HA, gelatin (Ge) and carboxymethyl cellulose (CMC) hydrogels are then introduced. It was found that cross-linking of the hydrogel matrix by glucose as a green reagent affected all characteristics of...
In vitro bactericidal and drug release properties of vancomycin-amino surface functionalized bioactive glass nanoparticles, Article Materials Chemistry and Physics ; Volume 241 , 2020 ; Ghorbani, M ; Bagheri, K.P ; Shokrgozar, M. A ; Sharif University of Technology
Elsevier Ltd 2020
Bioactive glass has been used clinically in bone repair applications for bone grafting because of its prominent physiochemical and osteogenic properties. Various attempts have been made to enhance bioactive glass efficiency in combination with other biomaterials such as antibiotics and growth factors. In present study, we developed a modification of bioactive glass nanoparticles that insured long term antibacterial effect. Bioactive glass nanoparticles (BGNs) were functionalized with (3-Aminopropyl) triethoxysilane (APTS), then vancomycin (VAN) was immobilized onto BGNs-APTS via EDC/NHS cross-linking process. Another study group namely BGNs-VAN was synthesized as a control group without any...
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...
Horseradish peroxidase immobilization on amine functionalized carbon nanotubes: Direct electrochemistry and bioelectrocatalysis, Article Progress in Reaction Kinetics and Mechanism ; Volume 37, Issue 2 , May , 2012 , Pages 161-172 ; 14686783 (ISSN) ; Ghourchian, H ; Gholami, M. R ; Rafiee Pour, H. A ; Sharif University of Technology
Horseradish peroxidase (HRP) was successfully immobilized on amine functionalized TiO 2-coated multiwalled carbon nanotubes (NH 2-TiO 2-CNTs) by a convenient and efficient method. Electrochemical impedance spectroscopy, cyclic voltammetry and amperometry were applied to characterize the HRP/NH 2-TiO 2-CNT nano-composite. These techniques showed that the NH 2-TiO 2-CNTs greatly enhance the electron transfer between HRP and the modified electrode. Owing to the redox reaction of the electroactive centre of HRP, the HRP/NH 2-TiO 2-CNTs modified electrode exhibited a pair of quasi-reversible peaks with a peak-to-peak separation (ΔE p) of 70.6mV and a formal potential (E 0′) of -367.65mV (versus...
Electrochemical determinations of 6-mercaptopurine on the surface of a carbon nanotube-paste electrode modified with a cobalt salophen complex, Article Journal of Solid State Electrochemistry ; Volume 16, Issue 4 , April , 2012 , Pages 1643-1650 ; 14328488 (ISSN) ; Ghorbani Bidkorbeh, F ; Mohammadi, A ; Dinarvand, R ; Sharif University of Technology
A mixture of multi-walled carbon nanotube/graphite paste electrode modified with a salophen complex of cobalt was prepared and was applied for the study of the electrochemical behavior of 6-mercaptopurine (MP) using cyclic and differential pulse voltammetry (DPV). An excellent electrocatalytic activity toward the oxidation of MP was achieved, which led to a considerable lowering in the anodic overpotential and remarkable increase in the response sensitivity in comparison with unmodified electrode. Utilizing DPV method, a linear dynamic range of 1-100 μM with detection limit of 0.1 μM was obtained in phosphate buffer of pH 3.0. The electrochemical detection system was very stable, and the...
Carbon-Pt nanoparticles modified TiO 2 nanotubes for simultaneous detection of dopamine and uric acid, Article Journal of Nanoscience and Nanotechnology ; Volume 11, Issue 8 , 2011 , Pages 6668-6675 ; 15334880 (ISSN) ; Luo, S ; Yang, L ; Mahshid, S. S ; Askari, M ; Dolati, A ; Cai, Q ; Sharif University of Technology
The present work describes sensing application of modified TiO 2 nanotubes having carbon-Pt nanoparticles for simultaneous detection of dopamine and uric acid. The TiO 2 nanotubes electrode was prepared using anodizing method, followed by electrodeposition of Pt nanoparticles onto the tubes. Carbon was deposited by decomposition of polyethylene glycol in a tube furnace to improve the conductivity. The C-Pt-TiO 2 nanotubes modified electrode was characterized by cyclic voltam-metry and differential pulse voltammetry methods. The modified electrode displayed high sensitivity towards the oxidation of dopamine and uric acid in a phosphate buffer solution (pH 7.00). The electro-oxidation currents...
Optimized composition of nanocomposite scaffolds formed from silk fibroin and nano-TiO2 for bone tissue engineering, Article Materials Science and Engineering C ; Volume 79 , 2017 , Pages 783-792 ; 09284931 (ISSN) ; Madaah Hosseini, H. R ; Samadikuchaksaraei, A ; Sharif University of Technology
Natural silk fibroin (SF) polymer has biomedical and mechanical properties as a biomaterial for bone tissue engineering scaffolds. Freeze-dried porous nanocomposite scaffolds were prepared from silk fibroin and titanium dioxide (TiO2) nanoparticles as a bioactive reinforcing agent by a phase separation method. In order to fabricate SF/TiO2 scaffolds, 5, 10, 15 and 20 wt% of the TiO2 were added to the SF. The phase structure, functional groups and morphology of the scaffolds were evaluated using X-ray diffraction, Fourier transform infrared spectroscopy and scanning electron microscopy techniques, respectively. Porosity of the scaffolds was measured by Archimedes' Principle. In addition,...
Modeling of a glucose sensitive composite membrane for closed-loop insulin delivery, 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...
Amperometric sulfide detection using Coprinus cinereus peroxidase immobilized on screen printed electrode in an enzyme inhibition based biosensor, Article Biosensors and Bioelectronics ; Volume 35, Issue 1 , 2012 , Pages 297-301 ; 09565663 (ISSN) ; Kariminia, H. R ; Ghadiri, M ; Roosta Azad, R ; Sharif University of Technology
In the present work, an amperometric inhibition biosensor for the determination of sulfide has been fabricated by immobilizing Coprinus cinereus peroxidase (CIP) on the surface of screen printed electrode (SPE). Chitosan/acrylamide was applied for immobilization of peroxidase on the working electrode. The amperometric measurement was performed at an applied potential of -150. mV versus Ag/AgCl with a scan rate of 100. mV in the presence of hydroquinone as electron mediator and 0.1. M phosphate buffer solution of pH 6.5. The variables influencing the performance of sensor including the amount of substrate, mediator concentration and electrolyte pH were optimized. The determination of sulfide...
Electrochemical determination of naltrexone on the surface of glassy carbon electrode modified with Nafion-doped carbon nanoparticles: Application to determinations in pharmaceutical and clinical preparations, Article Journal of Electroanalytical Chemistry ; Volume 638, Issue 2 , 2010 , Pages 212-217 ; 15726657 (ISSN) ; Shahrokhian, S ; Mohammadi, A ; Dinarvand, R ; Sharif University of Technology
A new sensitive and selective electrochemical sensor was developed for determination of naltrexone (NAL) in pharmaceutical dosage form and human plasma. Naltrexone is an opioid antagonist which is commonly used for the treatment of narcotic addiction and alcohol dependence. A voltammetric study of naltrexone has been carried out at the surface of glassy carbon electrode (GCE) modified with Nafion-doped carbon nanoparticles (CNPs). The electrochemical oxidation of naltrexone was investigated by cyclic and differential pulse voltammetric techniques. The dependence of peak currents and potentials on pH, concentration and the potential scan rate was investigated. The electrode characterization...
Novel fluoridated silk fibroin/ TiO2 nanocomposite scaffolds for bone tissue engineering, Article Materials Science and Engineering C ; Volume 82 , 2018 , Pages 265-276 ; 09284931 (ISSN) ; Madaah Hosseini, H. R ; Samadikuchaksaraei, A ; Sharif University of Technology
Elsevier Ltd 2018
It is known that Fluoride ions strongly affect bone mineralization and formation. In the present study, the engineered bone tissue scaffolds are fabricated using silk fibroin (SF) and flouridated TiO2 nanoparticles. TiO2 nanoparticles are modified by fluoride ions, and different levels (0, 5, 10, 15 and 20 wt%) of the fluoridated TiO2 nanoparticles (TiO2-F) were subsequently added to the SF matrix through phase separation method to prepare silk fibroin/flouridated TiO2 nanocomposite scaffolds (SF/TiO2-F). Phase structure, functional groups, morphology and mechanical properties of the obtained scaffolds were evaluated by X-ray diffraction method (XRD), Fourier transform infrared spectroscopy...