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metal-nanoparticle
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Enhanced electrochemical activity of a hollow carbon sphere/polyaniline-based electrochemical biosensor for HBV DNA marker detection
, Article ACS Biomaterials Science and Engineering ; Volume 5, Issue 5 , 2019 , Pages 2587-2594 ; 23739878 (ISSN) ; Shahrokhian, S ; Panahi, S ; Sharif University of Technology
American Chemical Society
2019
Abstract
Herein, we present a novel, simple, and ultrasensitive electrochemical DNA (E-DNA) sensor based on hollow carbon spheres (HCS) decorated with polyaniline (PANI). A thiolated 21-mer oligonucleotide, characteristic of HBV DNA, is immobilized via electrodeposited gold nanoparticles on HCS-PANI. Cyclic voltammetry (CV), differential pulse voltammetry (DPV), and electrochemical impedance spectroscopy (EIS) are used to characterize the electrochemical properties of the prepared nanocomposite. Scanning electron microscopy is employed to investigate the morphological texture of the fabricated modifier. An enhanced intrinsic signal of PANI is probed to evaluate the biosensing ability of the prepared...
Injectable chitosan/κ-carrageenan hydrogel designed with au nanoparticles: A conductive scaffold for tissue engineering demands
, Article International Journal of Biological Macromolecules ; Volume 126 , 2019 , Pages 310-317 ; 01418130 (ISSN) ; Doroudian, M ; Ahadpour, A ; Azari, S ; Sharif University of Technology
Elsevier B.V
2019
Abstract
Scaffolds for tissue engineering of specific sites such as cardiac, nerve, and bone tissues need a comprehensive design of three dimensional materials that covers all aspects of chemical composition and physical structures, required for regeneration of desired cells. Hydrogels, possessing highly hydrated and interconnected structures, are promising materials for tissue engineering applications. Improvement of an injectable hydrogel from biocompatible polysaccharides and poly‑N‑isopropyl acryl amide enriched with Au nanoparticles are the main goal of this study. Two main enhancements in this study are included mixture design of the components and addition of Au nanoparticles to access a...
Hardness, wear and friction characteristics of nanostructured Cu-SiC nanocomposites fabricated by powder metallurgy route
, Article Materials Today Communications ; Volume 18 , 2019 , Pages 25-31 ; 23524928 (ISSN) ; Najafi, M ; Alipour, S ; Kim, H.S ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
In the present study, hardness and tribological properties of nanostructured copper reinforced with SiC nanoparticles of various volume fractions (0, 2, 4, and 6 vol%) were investigated. The nanocomposites were fabricated by high-energy mechanical milling and hot pressing method. The Cu-SiC nanocomposites showed enhanced hardness and wear resistance against WC counterface. The hardness and wear resistance of the nanocomposite increased with increasing the amount of SiC nanoparticles up to 2 vol% in the matrix, but they decreased at higher percentages of SiC (4 and 6 vol%). Flake formation-spalling and abrasion were identified as the predominant wear mechanisms. It was found that reducing the...
ZIF-8/PEDOT @ flexible carbon cloth electrode as highly efficient electrocatalyst for oxygen reduction reaction
, Article International Journal of Hydrogen Energy ; 2019 ; 03603199 (ISSN) ; Shahrokhian, S ; Iraji Zad, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Design and fabrication of highly efficient and low-cost oxygen reduction reaction (ORR) electrocatalysts is of paramount importance for practical applications. Herein, we proposed a cost-effective, metal-free catalyst based on ZIF-8 metal-organic framework nanoparticles/electro-polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) film on the surface of flexible carbon cloth (CC) electrode (ZIF-8/PEDOT/CC) via a two-step procedure. For this purpose, worm-like PEDOT nanostructures were deposited on the surface of carbon fibers using a pulse electro-polymerization technique followed by facile growth of ZIF-8 polyhedra nanoparticles via a chemical bath deposition method. The ORR measurements in...
Backscattering-based detection scheme for dark-field optical tweezers
, Article Journal of the Optical Society of America B: Optical Physics ; Volume 36, Issue 6 , 2019 , Pages 1587-1593 ; 07403224 (ISSN) ; Mousavi, S. M ; Hajizadeh, F ; Reihani, S. N. S ; Sharif University of Technology
OSA - The Optical Society
2019
Abstract
Laser nanomanipulation by metallic nanoparticles, which are smaller than the diffraction limit, has become a great interest, especially in the manipulation of unstained biological samples. However, they are hard to image in bright-field microscopy, because of the diffraction limit. Thus, incorporation of a dark-field microscopy technique with optical tweezers would be an inevitable choice, enforcing the use of the backward scattering detection scheme. Here in this paper, we have taken into account the reflected light from the coverslip along with backscattered light from the trapped particle to validate and reveal some precautions of using this detection scheme, based on Mie-Debye...
ZIF-8/PEDOT @ flexible carbon cloth electrode as highly efficient electrocatalyst for oxygen reduction reaction
, Article International Journal of Hydrogen Energy ; 2019 ; 03603199 (ISSN) ; Shahrokhian, S ; Iraji Zad, A ; Sharif University of Technology
Elsevier Ltd
2019
Abstract
Design and fabrication of highly efficient and low-cost oxygen reduction reaction (ORR) electrocatalysts is of paramount importance for practical applications. Herein, we proposed a cost-effective, metal-free catalyst based on ZIF-8 metal-organic framework nanoparticles/electro-polymerized poly(3,4-ethylenedioxythiophene) (PEDOT) film on the surface of flexible carbon cloth (CC) electrode (ZIF-8/PEDOT/CC) via a two-step procedure. For this purpose, worm-like PEDOT nanostructures were deposited on the surface of carbon fibers using a pulse electro-polymerization technique followed by facile growth of ZIF-8 polyhedra nanoparticles via a chemical bath deposition method. The ORR measurements in...
Well-designed Ag/ZnO/3D graphene structure for dye removal: Adsorption, photocatalysis and physical separation capabilities
, Article Journal of Colloid and Interface Science ; Volume 537 , 2019 , Pages 66-78 ; 00219797 (ISSN) ; Samadi, M ; Asadian, E ; Zhou, Y ; Dong, C ; Zhang, J ; Moshfegh Zaker, A. R ; Sharif University of Technology
Academic Press Inc
2019
Abstract
In this research, adsorption and photocatalytic degradation process were utilized to remove organic dye from wastewater. To accomplish that, a newly-designed ternary nanostructure based on Ag nanoparticles/ZnO nanorods/three-dimensional graphene network (Ag NPs/ZnO NRs/3DG) was prepared using a combined hydrothermal-photodeposition method. The three-dimensional structure of graphene hydrogel as a support for growth of ZnO nanorods was characterized using field emission scanning electron microscopy (FESEM). In addition, diameter of silver nanoparticles grown on the ZnO nanorods with the average aspect ratio of 5 was determined in the range of 30–80 nm by using transmission electron microscopy...
Design and fabrication of an electrochemical aptasensor using Au nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite for rapid and sensitive detection of Staphylococcus aureus
, Article Bioelectrochemistry ; Volume 123 , 2018 , Pages 70-76 ; 15675394 (ISSN) ; Shahrokhian, S ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Since that pathogenic bacteria are major threats to human health, this paper describes the fabrication of an effective and durable sensing platform based on gold nanoparticles/carbon nanoparticles/cellulose nanofibers nanocomposite (AuNPs/CNPs/CNFs) at the surface of glassy carbon electrode for sensitive and selective detection of Staphylococcus aureus (S. aureus). The AuNPs/CNPs/CNFs nanocomposite with the high surface area, excellent conductivity, and good biocompatibility was used for self-assembled of the thiolated specific S. aureus aptamer as a sensing element. The surface morphology of AuNPs/CNPs/CNFs nanocomposite was characterized with field emission scanning electron microscopy...
Free energy, configurational and nonextensivity of Tsallis entropy with the size and temperature in colloidal silver nanoparticles in [EMim][PF6] ionic liquid
, Article Journal of Molecular Liquids ; Volume 249 , 2018 , Pages 1012-1019 ; 01677322 (ISSN) ; Taherkhani, F ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Molecular dynamic simulation was performed to calculate the configurational entropy and the free energy for colloidal silver nanoparticles (Ag NPs) in 1-Ethyl-3-methylimidazolium Hexafluorophosphate [EMim][PF6] ionic liquid (IL). Furthermore, the density functional theory (DFT) was used to get the potential interaction between the metal surface and ion in IL. The effect of size and temperature on the configurational entropy and the free energy of colloidal Ag NPs were investigated. Then, it was compared with the gas phase. The Tsallis nonextensivity of entropy was investigated for different sizes of colloidal Ag NPs and it was shown that sub-extensivity of entropy occurs for colloidal Ag...
Monolithic dye sensitized solar cell with metal foil counter electrode
, Article Organic Electronics ; Volume 57 , June , 2018 , Pages 194-200 ; 15661199 (ISSN) ; Taghavinia, N ; Ghazyani, N ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Monolithic dye-sensitized solar cells are conventionally fabricated using carbon composite layer as the counter electrode. In the current research, the brittle carbon composite layer is replaced with a metal foil, aiming to decrease the device series resistance and using less catalyst material in counter electrode. This metallic structure has also an advantage of mechanical strength and decreases the fabrication complexity. The counter electrode is prepared by electrodepositing Cr film followed by electrodepositing Pt nanoparticles on a metal foil. As the porous spacer layer, different composite layers of SiO2, TiO2, and Al2O3 are investigated and the best results are obtained for TiO2...
Performance of silver nanoparticle fixed on magnetic iron nanoparticles (Fe3O4−Ag) in water disinfection
, Article Micro and Nano Letters ; Volume 13, Issue 4 , April , 2018 , Pages 436-441 ; 17500443 (ISSN) ; Hassani, A. H ; Ahmad Panahi, H ; Borghei, M ; Sharif University of Technology
Institution of Engineering and Technology
2018
Abstract
Microbial contamination poses a serious threat to human health. The evaluation of alternative systems and their reliability for the treatment of water is essential. In this work, a new method for the deposit of more silver nanoparticles (AgNPs) on the external surface of Fe3O4 nanoparticles is presented. Fe3O4 nanoparticles were synthesised by chemical co-precipitation and were modified in two stages using 3-mercaptopropyl trimethoxysilane and grafting allyl glycidyl ether and N, N-dimethylacrylamide. Then, AgNPs were loaded onto the modified Fe3O4 to be used for water disinfection. The resulting nanoparticles were characterised by transmission electron microscopy, X-ray powder diffraction,...
Synthesis of metal nanoparticles using laser ablation technique
, Article Emerging Applications of Nanoparticles and Architectural Nanostructures: Current Prospects and Future Trends ; March , 2018 , Pages 575-596 ; 9780128135167 (ISBN); 9780323512541 (ISBN) ; Vahdatkhah, P ; Sharif University of Technology
Elsevier Inc
2018
Abstract
Pulse laser ablation (PLA) technique has been demonstrated to be a simple, compatible, promising, versatile, relatively low-cost, pure, and green approach with the absence of toxic chemicals and reagents for fabrication of metal nanoparticles. Purity is an especially important attribute of metal nanoparticles (NPs) in biological and medical technologies. For such applications, it is crucial to prepare metal NPs with the desired shape and size distribution. This chapter discusses the advantages of the PLA technique as compared with other techniques for metal NPs, explains the various mechanisms involved in the generation of metal NPs, outlines the effects of laser parameters, such as...
Silver nanoparticles immobilized onto poly(4-vinylpyridine)-functionalized magnetic nanoparticles: a robust magnetically recyclable catalyst for oxidant-free alcohol dehydrogenation
, Article Applied Organometallic Chemistry ; Volume 32, Issue 2 , February , 2018 ; 02682605 (ISSN) ; Shakourian Fard, M ; Talebloo, N ; Mahmoodi Hashemi, M ; Sharif University of Technology
John Wiley and Sons Ltd
2018
Abstract
A heterogeneous and recyclable catalyst with a high loading of silver nanoparticles was synthesized via the silver nanoparticles being supported onto the surface of magnetic nanoparticles coated with poly(4-vinylpyridine). The synthesized catalyst was used in the dehydrogenation of alcohols to corresponding carbonyl compounds. A broad diversity of alcohols was converted into their corresponding carbonyl compounds in excellent yields. The catalyst was easily recovered by applying an external magnetic field and reused for seven reaction cycles without considerable loss of activity. The catalyst was fully characterized using various techniques. Copyright © 2017 John Wiley & Sons, Ltd
Inhibitory effects of functionalized indium doped ZnO nanoparticles on algal growth for preservation of adobe mud and earthen-made artworks under humid conditions
, Article International Biodeterioration and Biodegradation ; Volume 127 , Febraury , 2018 , Pages 209-216 ; 09648305 (ISSN) ; Mallakin, A ; Malekmohammady, F ; Khosravi Nejad, F ; Sharif University of Technology
Elsevier Ltd
2018
Abstract
In this article, indium doped ZnO nanoparticles (alloy nanoparticles) were investigated as inhibitors against algae growth on adobe mud and earthen artworks for surface preservation from destruction caused by micro-organisms under humid conditions, through surface modification and activation run off. Nanoparticles (NPs) were fabricated by physical vapor deposition (PVD) growth mechanism. The fabricated NPs were approximately 20 nm in size. The Chlorella vulgaris and Scenedesmus quadricauda were tested by application of indium doped ZnO nanoparticles (In/ZnO NPs) as inhibitors. As concentrations of NPs increased, the negative impacts of NPs on the algal growth were enhanced and physical...
Shed light on submerged DC arc discharge synthesis of low band gap gray Zn/ZnO nanoparticles: Formation and gradual oxidation mechanism
, Article Advanced Powder Technology ; Volume 29, Issue 5 , 2018 , Pages 1246-1254 ; 09218831 (ISSN) ; Poursalehi, R ; Naseri, N ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Synthesis of colloidal metal oxides with controllable size and morphology is burgeoning field of research in nanoscience. Low band gap gray Zn/ZnO colloidal nanoparticles were fabricated by plasma-liquid interaction of DC arc discharge in water. Scanning electron microscopy, X-ray diffraction and UV–vis spectroscopy were employed for morphology, crystal structure and optical characterizations respectively. Optical emission spectroscopy was used to investigate the plasma properties during the synthesis and formation mechanism of nanoparticles. Nanoparticles with different size and shape were fabricated only by adjusting discharge current during synthesis without introducing any chemical...
Noble metal nanostructures in optical biosensors: basics, and their introduction to anti-doping detection
, Article TrAC - Trends in Analytical Chemistry ; Volume 100 , 2018 , Pages 116-135 ; 01659936 (ISSN) ; Sahandi Zangabad, P ; Mohammadi, H ; Sadroddini, M ; Jafari, Z ; Mahlooji, N ; Abbaspour, S ; Gholami, S ; Ghanbarpoor, M ; Pashazadeh, R ; Beyzavi, A ; Karimi, M ; Hamblin, M. R ; Sharif University of Technology
Elsevier B.V
2018
Abstract
Nanotechnology has illustrated significant potentials in biomolecular-sensing applications; particularly its introduction to anti-doping detection is of great importance. Illicit recreational drugs, substances that can be potentially abused, and drugs with dosage limitations according to the prohibited lists announced by the World Antidoping Agency (WADA) are becoming of increasing interest to forensic chemists. In this review, the theoretical principles of optical biosensors based on noble metal nanoparticles, and the transduction mechanism of commonly-applied plasmonic biosensors are covered. We review different classes of recently-developed plasmonic biosensors for analytic determination...
Switchable on/off drug release from gold nanoparticles-grafted dual light- and temperature-responsive hydrogel for controlled drug delivery
, Article Materials Science and Engineering C ; Volume 76 , 2017 , Pages 242-248 ; 09284931 (ISSN) ; Sadighi Bonabi, R ; Pourghazi, K ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
A switchable dual light- and temperature-responsive drug carrier using gold nanoparticles (Au NPs)-grafted poly(dimethylacrylamide-co-acrylamide)/poly acrylic acid [P(DMA-co-AAm)/PAAc] hydrogel was prepared by free radical polymerization procedure using N,N-methylenebisacrylamide as cross-linker and ammonium persulfate as initiator. Initial P(DMA-co-AAm) hydrogel and uniformly-distributed stable Au NPs, prepared by reduction of hydrogen tetrachloroaureate (III) hydrate in the presence of trisodium citrate, were synthesized separately. Then, the prepared P(DMA-co-AAm) and Au NPs were added to an acrylic acid solution along with the cross-linker and initiator to prepare PAAc hydrogel within...
Laser-assisted triggered-drug release from silver nanoparticles-grafted dual-responsive polymer
, Article Materials Science and Engineering C ; Volume 76 , 2017 , Pages 536-542 ; 09284931 (ISSN) ; Sadighi Bonabi, R ; Pourghazi, K ; Sharif University of Technology
Elsevier Ltd
2017
Abstract
Laser assisted drug release from a synthesized plain polymer composed of poly (butyl methacrylate-co-acrylamide-co-methacrylic acid) [P(BMA-co-AAm-co-MAA)] and a metallo-polymer composed of silver nanoparticles (Ag NPs) grafted plain polymer (the nanocomposite) were studied to investigate their capability to serve as drug carriers. Positive temperature dependent swelling changes were observed for both carriers and their thermal sensitivity and thermal and optical switching properties were investigated in two buffered solutions. An acidic solution with pH = 1.2 to simulate stomach body condition and a neutral solution with pH = 7.4 to simulate intestine condition. Reversible phase transition...
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
Abstract
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...
Simultaneous electrodeposition of reduced graphene oxide/ag nanoparticles as a sensitive layer for voltammetric determination of tinidazole
, Article Nano ; Volume 12, Issue 6 , 2017 ; 17932920 (ISSN) ; Navabi, M ; Mohammadi, R ; Sharif University of Technology
World Scientific Publishing Co. Pte Ltd
2017
Abstract
A stable composite film of silver nanoparticles (Ag NPs) decorated on reduced graphene oxide is prepared by a two-step simple procedure. The surface morphology of the modified electrode is characterized by scanning electron microscopy (SEM) and atomic force microscopy (AFM) techniques. The electrochemical behavior of tinidazole (TNZ) on the surface of the modified electrode is investigated by linear sweep voltammetry and electrochemical impedance spectroscopy. The prepared composite electrode acts as a highly sensitive platform for the voltammetric determination of TNZ, leading to a significant increase in the reduction peak current of TNZ. The effects of experimental parameters such as the...