Search for: chemical-detection
Total 38 records
Noble metal nanoparticles in biosensors: Recent studies and applications, Article Nanotechnology Reviews ; Volume 6, Issue 3 , 2017 , Pages 301-329 ; 21919089 (ISSN) ; Sahandi Zangabad, P ; Mirshekari, H ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
Walter de Gruyter GmbH 2017
The aim of this review is to cover advances in noble metal nanoparticle (MNP)-based biosensors and to outline the principles and main functions of MNPs in different classes of biosensors according to the transduction methods employed. The important biorecognition elements are enzymes, antibodies, aptamers, DNA sequences, and whole cells. The main readouts are electrochemical (amperometric and voltametric), optical (surface plasmon resonance, colorimetric, chemiluminescence, photoelectrochemical, etc.) and piezoelectric. MNPs have received attention for applications in biosensing due to their fascinating properties. These properties include a large surface area that enhances biorecognizers...
Human detection in occluded scenes through optically inspired multi-camera image fusion, Article Journal of the Optical Society of America A: Optics and Image Science, and Vision ; Volume 34, Issue 6 , 2017 , Pages 856-869 ; 10847529 (ISSN) ; Kavehvash, Z ; Aghajan, H ; Sharif University of Technology
In this paper, a novel approach for foreground extraction has been proposed based on a popular three-dimensional imaging technique in optics, called integral imaging. In this approach, multiple viewpoint images captured from a three-dimensional scene are used to extract range information of the scene and effectively extract an object or a person, even in the presence of heavy occlusion. The algorithm consists of two parts: depth estimation and reconstruction of the targeted object at the estimated depth distance. Further processing of the resulting reconstructed image can lead to the detection of a face or a pedestrian in the scene, which may not otherwise be detectable due to partial...
Construction of Pt nanoparticle-decorated graphene nanosheets and carbon nanospheres nanocomposite-modified electrodes: Application to ultrasensitive electrochemical determination of cefepime, Article RSC Advances ; Volume 4, Issue 15 , 2014 , Pages 7786-7794 ; ISSN: 20462069 ; Hosseini Nassab, N ; Ghalkhani, M ; Sharif University of Technology
A novel ultrasensitive modified electrode was fabricated with a graphene nanosheets and carbon nanospheres (GNS-CNS)-based nanocomposite film as a powerful platform. Pt nanoparticles (PtNPs) were simply electrodeposited onto the GNS-CNS-coated glassy carbon electrode creating a PtNPs/GNS-CNS hybrid nanocomposite modified electrode. Scanning electron microscopy, energy dispersive X-ray spectroscopy and linear sweep voltammetry (LSV) techniques were used for the characterization of the prepared modified electrode. The results of investigation of electrochemical response characteristics of cefepime (CP) revealed a considerable improvement in the oxidation peak current of CP on PtNPs/GNS-CNS/GCE...
Ultra-sensitive detection of leukemia by graphene, Article Nanoscale ; Vol. 6, issue. 24 , Dec , 2014 , p. 14810-14819 ; Ghaderi, E ; Hashemi, E ; Rahighi, R ; Sharif Universit of Technology
Graphene oxide nanoplatelets (GONPs) with extremely sharp edges (lateral dimensions ∼20-200 nm and thicknesses <2 nm) were applied in extraction of the overexpressed guanine synthesized in the cytoplasm of leukemia cells. The blood serums containing the extracted guanine were used in differential pulse voltammetry (DPV) with reduced graphene oxide nanowall (rGONW) electrodes to develop fast and ultra-sensitive electrochemical detection of leukemia cells at leukemia fractions (LFs) of ∼10-11 (as the lower detection limit). The stability of the DPV signals obtained by oxidation of the extracted guanine on the rGONWs was studied after 20 cycles. Without the guanine extraction, the DPV peaks...
Highly sensitive 3D gold nanotube ensembles: Application to electrochemical determination of metronidazole, Article Electrochimica Acta ; Volume 106 , 2013 , Pages 288-292 ; 00134686 (ISSN) ; Ghorbani, M ; Ghalkhani, M ; Vossoughi, M ; Dolati, A ; Sharif University of Technology
Three-dimensional gold nanoelectrode ensembles (3D GNE) have proven to be promising nanoelectrodes by representing much higher sensitivity compared to both their 2D nanostructures and bulk counterparts. The sensitivity of 3D gold nanotubes (GNTs) fabricated through electrodeposition inside the pores of polycarbonate templates, was examined toward metronidazole (MTZ) as one of their pharmaceutical applications. The electrochemical behavior of MTZ at the 3D GNT-modified electrode was discussed in detail through cyclic voltammetry (CV) which suggested an irreversible reduction of nitro group to the corresponding hydroxylamine and a subsequently reversible redox peak for the corresponding...
Thermal transport characteristics of non-newtonian electroosmotic flow in a slit microchannel, Article ASME 2011 9th International Conference on Nanochannels, Microchannels, and Minichannels, ICNMM 2011, 19 June 2011 through 22 June 2011 ; Volume 1 , June , 2011 , Pages 169-176 ; 9780791844632 (ISBN) ; Sadeghi, A ; Saidi, M. H ; Sharif University of Technology
Electroosmosis has many applications in fluid delivery at microscale, sample collection, detection, mixing and separation of various biological and chemical species. In biological applications, most fluids are known to be non-Newtonian. Therefore, the study of thermal features of non-Newtonian electroosmotic flow is of great importance for scientific communities. In the present work, the fully developed electroosmotic flow of power-law fluids in a slit microchannel is investigated. The related equations are transformed into non-dimensional forms and necessary changes are made to adapt them for non-Newtonian fluids of power-law model. Results show that depending on different flow parameters...
Electrochemical determination of CdS band edges and semiconducting parameters, Article Bulletin of the Chemical Society of Japan ; Volume 88, Issue 6 , February , 2015 , Pages 814-820 ; 00092673 (ISSN) ; Jafarian, M ; Mahjani, M. G ; Gobal, F ; Heidaripour, A ; Sharif University of Technology
Chemical Society of Japan 2015
Cadmium sulfide (CdS) thin film was electrodeposited on indium tin oxide (ITO) by chronoamperometry. The SEM images showed that hexagonal sheets of CdS deposited on the ITO surface. The X-ray diffraction (XRD) analysis confirmed this structure for CdS crystals and the average of crystalline size and the lattice constant parameters are approximately 39.54 and a = 0.4136, c = 0.6696 nm respectively. Photo-electrochemical investigations were performed by cyclic voltammetry (CV), linear sweep voltammetry (LSV), and electrochemical impedance spectroscopy (EIS) techniques. CdS band edges and density of states (DOS) were determined by CV technique. The band gap energy (E
bg) was measured...
Dual improvement of DNA-directed antibody immobilization utilizing magnetic fishing and a polyamine coated surface, Article RSC Advances ; Volume 6, Issue 112 , 2016 , Pages 111210-111216 ; 20462069 (ISSN) ; Soleimani, M ; Shamloo, A ; Mahmoudifard, M ; Vossoughi, M ; Sharif University of Technology
Royal Society of Chemistry 2016
The present study is aimed at the development of a novel approach based on the magnetic improvement of DNA-directed antibody immobilization to prepare a highly efficient sensing platform. Magnetic nanoparticle substrates with high surface area capture the dual DNA-conjugated antibodies in a solution. This allows overcoming the typical mass transport limitation of the surface-based antibody immobilization. Antibody-magnetic nanoparticle conjugation is based on a robust hybridization between a DNA tether (attached to the antibody) and its complementary sequence (immobilized on the nanoparticle). Conventional antibody immobilization for the detection of proteins is often insignificant for the...
Glassy carbon electrode modified with 3D graphene–carbon nanotube network for sensitive electrochemical determination of methotrexate, Article Sensors and Actuators, B: Chemical ; Volume 239 , 2017 , Pages 617-627 ; 09254005 (ISSN) ; Shahrokhian, S ; Iraji Zad, A ; Ghorbani Bidkorbeh, F ; Sharif University of Technology
Elsevier B.V 2017
In the present study, a 3D porous graphene-carbon nanotube (G-CNT) network is successfully constructed on the surface of glassy carbon electrode (GCE) by electrochemical co-deposition from a concentrated graphene dispersion. The large accessible surface area provided by the interpenetrated graphene backbone in one hand and the enhanced electrical conductivity of the 3D network by incorporating CNTs on the other hand, dramatically improved the electrochemical performance of GCE in determination of Methotrexate (MTX) as an important electroactive drug compound. Under the optimum conditions, the electrode modification led to a significant increase in the anodic peak current (∼25 times) along...
Characterization of three-dimensional reduced graphene oxide/copper oxide heterostructures for hydrogen sulfide gas sensing application, Article Journal of Alloys and Compounds ; Volume 740 , 2018 , Pages 1024-1031 ; 09258388 (ISSN) ; Iraji zad, A ; Hosseini, Z. S ; Jokar, E ; Sharif University of Technology
Elsevier Ltd 2018
Three-dimensional reduced graphene oxide (3D-rGO) structures decorated with CuO particles (GCu) are synthesized through a simple and scalable method for detection of hydrogen sulfide (H2S) gas. For characterization and investigation of porous structure various techniques were employed. Decorated 3D structures demonstrated higher sensitivity and selectivity in comparison to pure structure. Optimized structure for sensing was obtained through introducing different amounts of CuO. The GCu heterostructures containing 35 μmol of CuO powder demonstrated reproducible response of about 30% to the concentration of 10 ppm at room temperature, while complete recovery was obtained through heating to 150...
Nanoporous gold as a suitable substrate for preparation of a new sensitive electrochemical aptasensor for detection of salmonella typhimurium, Article Sensors and Actuators, B: Chemical ; Volume 255 , 2018 , Pages 1536-1544 ; 09254005 (ISSN) ; Shahrokhian, S ; Nurmohammadi, F ; Sharif University of Technology
Elsevier B.V 2018
Nowadays, achievement to easy, fast, reliable and cost-effective techniques and tools is one of the most important challenges in detection of microorganisms. Salmonella typhimurium is one of the most important pathogenic bacteria that affect the human health and environmental infections. In this work we report a new, stable, biocompatible and cost-effective platform for construction of an aptasensor based on nanoporous gold (NPG) for detection of S. typhimurium. Nanoporous gold is electrochemically synthesized using Au-Cu alloy at the surface of Au/GCE. Thiol functionalized aptamer is used for effective linking to the surface of NPG/Au/GCE via self-assemble monolayers (SAMs) formation....
Turn-off chelation-enhanced fluorescence sensing of carbon dot-metallic deep eutectic solvent by imidazole-based small molecules, Article Sensors and Actuators B: Chemical ; Volume 344 , 2021 ; 09254005 (ISSN) ; Bagheri, H ; Es-haghi, A ; Sharif University of Technology
Elsevier B.V 2021
Low accuracy, requirement of expensive instruments, derivatization and multi-step sample preparation, inconsistencies during the fabrication process, time-consuming procedures and utilization of eco-unfriendly chemicals are some limitations of various developed methods for detection of 4-methylimidazol (4-MeI). Herein, a rapid and miniaturized fluorescent probe based on the ultrasound‒assisted formation of carbon dots (CDs) in a metallic deep eutectic solvent (MDES) was developed and conveniently implemented to detect 4-MeI in commercial dark soft drinks. In-situ synthesis of CDs-chelated metals in the presence of the target analyte facilitates a kinetically fluorescence emission with no...
In-situ electro-polymerization of graphene nanoribbon/polyaniline composite film: Application to sensitive electrochemical detection of dobutamine, Article Sensors and Actuators, B: Chemical ; Vol. 196 , June , 2014 , pp. 582-588 ; ISSN: 09254005 ; Shahrokhian, S ; Zad, A. I ; Jokar, E ; Sharif University of Technology
The present paper demonstrates the capability of narrow graphene nanoribbons (GNRs) in constructing new sensing platforms. Graphene nanoribbons have been synthesized via a simple solvothermal route through unzipping of carbon nanotubes, which was confirmed by scanning electron microscopy (SEM), transmission electron microscopy (TEM), X-ray diffraction (XRD) and Raman spectroscopy analysis. These narrow carbon sheets were used to form a composite film by in-situ electro-polymerization with aniline. The produced graphene nanoribbon/polyaniline (GNR/PANI) composite film showed impressive performance in electrochemical determination of dobutamine (DBT). Under optimal conditions, in comparison to...
Pd-Au nanoparticle decorated carbon nanotube as a sensing layer on the surface of glassy carbon electrode for electrochemical determination of ceftazidime, Article Materials Science and Engineering C ; Vol. 34, issue. 1 , 2014 , pp. 318-325 ; ISSN: 09284931 ; Salimian, R ; Rastgar, S ; Sharif University of Technology
A simple electrodeposition method is employed to construct a thin film modifier of palladium-gold nanoparticles (Pd-AuNPs) decorated multi-walled carbon nanotube (MWCNT) on the surface of glassy carbon electrode (GCE). Morphology and property of Pd-AuNPs-MWCNT have been examined by scanning electron microscopy (SEM) and energy dispersive spectroscopy (EDS). Electrochemical performance of Pd-AuNPs-MWCNT/GCE for detection of ceftazidime (CFZ) has been investigated by cyclic voltammetry (CV). This nanostructured film modified electrode effectively exhibited enhanced properties for detection of ceftazidime (CFZ). The effects of various experimental variables such as, the amount of casted MWCNT,...
CO gas sensor properties of Cu@CuO core-shell nanoparticles based on localized surface plasmon resonance, Article Journal of Physical Chemistry C ; Volume 115, Issue 45 , 2011 , Pages 22126-22130 ; 19327447 (ISSN) ; Zahrabi, H ; Saani, M. H ; Vesaghi, M. A ; Sharif University of Technology
Hexagonal array of Cu@CuO core-shell nanoparticles (NPs) on the a-C:H thin film was prepared by codeposition of RF-sputtering and RF-PECVD. The trace of hexagonal NPs supperlattice was recognized by AFM image and XRD result. On the basis of localized surface plasmon resonance (LSPR) of core-shell NPs, the prepared array detected a low flow rate of CO gas at room temperature. XPS results indicate that the surface of Cu@CuO core-shell NPs have no chemical reaction with CO molecule. The physical absorption of CO molecule on the surface of Cu@CuO core-shell NPs increases the LSPR absorbance and causes a red shift in LSPR wavelength. These experimental results are in agreement with Mie theory...
Game-theoretic approach to mitigate packet dropping in wireless Ad-hoc networks, Article 2011 IEEE Consumer Communications and Networking Conference, CCNC'2011, 8 January 2011 through 11 January 2011, Las Vegas, NV ; 2011 , Pages 163-165 ; 9781424487905 (ISBN) ; Farhat, F ; Pakravan, M. R ; Aref, M. R ; Sharif University of Technology
Performance of routing is severely degraded when misbehaving nodes drop packets instead of properly forwarding them. In this paper, we propose a Game-Theoretic Adaptive Multipath Routing (GTAMR) protocol to detect and punish selfish or malicious nodes which try to drop information packets in routing phase and defend against collaborative attacks in which nodes try to disrupt communication or save their power. Our proposed algorithm outranks previous schemes because it is resilient against attacks in which more than one node coordinate their misbehavior and can be used in networks which wireless nodes use directional antennas. We then propose a game theoretic strategy, ERTFT, for nodes to...
Electrochemical preparation of a molecularly imprinted polypyrrole modified pencil graphite electrode for the determination of phenothiazine in model and real biological samples, Article Talanta ; Volume 144 , November , 2015 , Pages 456-465 ; 00399140 (ISSN) ; Rouki, Z ; Nezhadali, M ; Sharif University of Technology
Abstract A sensitive electrochemical sensor for determination of phenothiazine (PTZ) was introduced based on molecularly imprinted polymer (MIP) film. A computational study was performed to evaluate the template-monomer geometry and interaction energy in the prepolymerization mixture. The electrode was prepared during electropolymerization of pyrrole (Py) on a pencil graphite electrode (PGE) by cyclic voltammetry (CV) technique. The quantitative measurements were performed using differential pulse voltammetry (DPV) in Britton-Robinson (BR) buffer solutions using 60% (v/v) acetonitrile-water (ACN/H
2O) binary solvent. The effect of important parameters like pH, monomer...
Design and fabrication of sensitive carbon nanotubes/PMMA film for acetone vapour detection, Article International Journal of Nanomanufacturing ; Volume 5, Issue 3-4 , 2010 , Pages 268-277 ; 17469392 (ISSN) ; Iraji Zad, A ; Hormozi Nezhad, M. R ; Sharif University of Technology
We present gas sensing property of carbon nanotubes (CNTs) polymethylmethacrylate (PMMA) composite as the active element for acetone vapour detection at room temperature. The polymeric films were formed by spin coating method on SiO2 substrates. Then they were activated by dropping the CNTs suspension in acetone on the PMMA films. The CNT/PMMA films were characterised by SEM, TEM and Raman spectroscopy. Variation of film's electrical resistance after exposure polar and non-polar gases is utilised as the principle of gas sensing. The experimental results showed that the samples present chemical selectivity and reversibility toward polar gases especially acetone vapour
Glassy carbon electrodes modified with a film of nanodiamond-graphite/chitosan: Application to the highly sensitive electrochemical determination of Azathioprine, Article Electrochimica Acta ; Volume 55, Issue 11 , 2010 , Pages 3621-3627 ; 00134686 (ISSN) ; Ghalkhani, M ; Sharif University of Technology
A novel modified glassy carbon electrode with a film of nanodiamond-graphite/chitosan is constructed and used for the sensitive voltammetric determination of azathioprine (Aza). The surface morphology and thickness of the film modifier are characterized using atomic force microscopy. The electrochemical response characteristics of the electrode toward Aza are investigated by means of cyclic voltammetry. The modified electrode showed an efficient catalytic role for the electrochemical reduction of Aza, leading to a remarkable decrease in reduction overpotential and enhancement of the kinetics of the electrode reaction with a significant increase of peak current. The effects of experimental...
An optimum pre-filter for ICA based multi-input multi-output OFDM system, Article International Journal of Innovative Computing, Information and Control ; Volume 7, Issue 6 , June , 2011 , Pages 3499-3508 ; 13494198 (ISSN) ; Asharif, M. R ; Khosravi, M ; Yamashita, K ; Sharif University of Technology
This paper presents an optimum pre-filter for ICA based multi-input multi-output OFDM system. In our former work, we presented a pre-filter solution for multiuser reconstruction in ICA based MIMO-OFDM systems [1,2]. Here, based on the structure of the system and former pre-filter solution, an optimization problem has been designed to give us the optimum pre-filter. The designed problem is based on minimization of the estimation error of ambiguities inherent to ICA in reconstruction of the data after separation. The optimization problem is mathematically solved and a set of optimized coefficients are obtained. Among the obtained set as optimum coefficients, optimum coefficients are acquired...