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    A colorimetric assay for d-Penicillamine in urine and plasma samples based on the aggregation of gold nanoparticles

    , Article Journal of the Iranian Chemical Society ; Vol. 11, issue. 5 , Dec , 2014 , p. 1249-1255 Hormozi-Nezhad, M. R ; Azargun, M ; Fahimi-Kashani, N ; Sharif University of Technology
    2014
    Abstract
    We report herein the development of a highly sensitive colorimetric method for detection of d-Penicillamine using citrate-capped gold nanoparticles (AuNPs). This assay relies upon the distance-dependent of gold nanoparticles surface plasmon resonance band of gold nanoparticles. By replacing the thiol-containing chelator drug, d-Penicillamine, with citrate on the gold nanoparticles surface, a new peak appearing at a longer wavelength intensifies and shifts further to the red from the original peak position due to aggregation of gold nanoparticles which depends on ionic strength, gold nanoparticles and d-Penicillamine concentration. During this process, the plasmon band at 521 nm decreases... 

    Mining the potential of label-free biosensors for in vitro antipsychotic drug screening

    , Article Biosensors ; Volume 8, Issue 1 , 2018 ; 20796374 (ISSN) Kilic, T ; Soler, M ; Fahimi Kashani, N ; Altug, H ; Carrara, S ; Sharif University of Technology
    MDPI AG  2018
    Abstract
    The pharmaceutical industry is facing enormous challenges due to high drug attribution rates. For the past decades, novel methods have been developed for safety and efficacy testing, as well as for improving early development stages. In vitro screening methods for drug-receptor binding are considered to be good alternatives for decreasing costs in the identification of drug candidates. However, these methods require lengthy and troublesome labeling steps. Biosensors hold great promise due to the fact that label-free detection schemes can be designed in an easy and low-cost manner. In this paper, for the first time in the literature, we aimed to compare the potential of label-free optical and... 

    Gold-nanoparticle-based colorimetric sensor array for discrimination of organophosphate pesticides

    , Article Analytical Chemistry ; Volume 88, Issue 16 , 2016 , Pages 8099-8106 ; 00032700 (ISSN) Fahimi Kashani, N ; Hormozi Nezhad, M. R ; Sharif University of Technology
    American Chemical Society  2016
    Abstract
    There is a growing interest in developing high-performance sensors monitoring organophosphate pesticides, primarily due to their broad usage and harmful effects on mammals. In the present study, a colorimetric sensor array consisting of citrate-capped 13 nm gold nanoparticles (AuNPs) has been proposed for the detection and discrimination of several organophosphate pesticides (OPs). The aggregation-induced spectral changes of AuNPs upon OP addition has been analyzed with pattern recognition techniques, including hierarchical cluster analysis (HCA) and linear discriminant analysis (LDA). In addition, the proposed sensor array has the capability to identify individual OPs or mixtures of them in... 

    Gold nanorod-based chrono-colorimetric sensor arrays: a promising platform for chemical discrimination applications

    , Article ACS Omega ; Volume 3, Issue 2 , 2018 , Pages 1386-1394 ; 24701343 (ISSN) Fahimi Kashani, N ; Hormozi Nezhad, M. R ; Sharif University of Technology
    American Chemical Society  2018
    Abstract
    Most array-based sensing platforms, to date, utilize static response patterns for discrimination of a wide variety of analytes, but only a few studies have focused on the important task of quantitatively resolving structural isomers, which are nowadays important because of their broad usage in medicines and industries. A possible way of accomplishing this feat is to combine kinetic (rather than static) sensor response profiles with the chemical tongue strategy to allow the development of array-based sensors for isomeric discrimination. Here, by adding the time dimension, a simple and novel gold nanorod (AuNR)-based chrono-colorimetric sensor array is proposed for chemical discrimination... 

    A smart-phone based ratiometric nanoprobe for label-free detection of methyl parathion

    , Article Sensors and Actuators, B: Chemical ; Volume 322 , 2020 Fahimi Kashani, N ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Elsevier B.V  2020
    Abstract
    The widespread use of pesticides in pest management has boosted the demands for developing highly sensitive probes for on-site monitoring. Herein we presented a sensitive enzyme-free ratiometric probe for determination of methyl parathion (MP), as an organophosphate pesticide using TGA-capped CdTe QDs and carbon dots (CDs). Unlike previous methods in which hydrolysis product of MP is instrumental in the response of the sensors, here, self-assembly of cetyltrimethylammonium bromide (CTAB) on the surface of non-modified yellow-emissive CdTe QDs facilitates the quenching of CTAB-QDs upon addition of MP while the fluorescence intensity of CDs remains constant. Using a smartphone, the ratiometric... 

    Colorimetric Sensing of Nitrite and Glutathione Based on Morphological Changes of High Aspect Ratio of Gold Nanorods

    , M.Sc. Thesis Sharif University of Technology Fahimi - Kashani, Nafiseh (Author) ; Hormozi Nezhad, Mohammad Reza (Supervisor)
    Abstract
    The fascinating size-dependent properties of noble metal nanop articles have created a great promise for their use in a different applications specially chemical sensing. Gold nanorods (GNRs), specifically, have received a great deal of attention due to their unusual optical properties. The nanoscale confinement of electrons on the surface of gold nanorods grants them aspect ratio-dependent properties not seen in larger particles. Due to the intriguing properties of GNRs, significant work has gone into the application of nanorods for sensing and detection of various an alytes in biological and other systems. The major modalities which have been developed for... 

    Colorimetric detection of glutathione based on transverse overgrowth of high aspect ratio gold nanorods investigated by MCR-ALS

    , Article RSC Advances ; Volume 5, Issue 101 , 2015 , Pages 82906-82915 ; 20462069 (ISSN) Fahimi Kashani, N ; Shadabipour, P ; Hormozi-Nezhad, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2015
    Abstract
    In this paper, we present a simple platform for colorimetric detection of glutathione using gold nanorods (AR ∼ 6.5 ± 0.2) as a plasmonic sensor. The functional mechanism of the sensor is based on shifts of longitudinal plasmon resonance during selective transverse overgrowth induced by preferential binding of glutathione at the nanorod tips. Under the optimum conditions, a calibration curve showed two linear regimes at the range of 50 nM to 20 μM of glutathione with a detection limit as low as 40 nM. The nanosensor maintains relatively high selectivity for determination of glutathione in the presence of several other amino acids. However, cysteine at similar concentration levels strongly... 

    Optical Sensor Arrays Based on Nanostructured Materials for Quantitative Detection and Qualitative Discrimination of Pesticides and Structural Isomers

    , Ph.D. Dissertation Sharif University of Technology Fahimi-Kashani, Nafiseh (Author) ; Hormozi-Nezhad, Mohammad Reza (Supervisor)
    Abstract
    There is a growing interest in developing high-performance sensors monitoring organophosphate pesticides, primarily due to their broad usage and harmful effects on mammals. In the first part of this research, by introducing conditional sensor elements (CSE), a colorimetric sensor array has been proposed for the detection and discrimination of several organophosphate pesticides (OPs). citrate-capped 13 nm gold nanoparticles (AuNPs) at nine different pH/ionic strengths were employed as simple plasmonic sensing elements in the development of a colorimetric sensor array for the detection and discrimination of five organophosphate pesticides, including azinphos-methyl (AM), chlorpyrifos (CP),... 

    MoS2 quantum-dots as a label-free fluorescent nanoprobe for the highly selective detection of methyl parathion pesticide

    , Article Analytical Methods ; Volume 9, Issue 4 , 2017 , Pages 716-723 ; 17599660 (ISSN) Fahimi Kashani, N ; Rashti, A ; Hormozi Nezhad, M. R ; Mahdavi, V ; Sharif University of Technology
    Royal Society of Chemistry  2017
    Abstract
    A reliable, simple, and sensitive fluorescence method was developed for the determination of methyl parathion (MP) in rice using MoS2 quantum dots (QDs). Rapid hydrolysis of MP under alkaline conditions, and thus the formation of p-nitrophenol (p-NP) can be used for MP detection. The functional mechanism of the nanoprobe relies on p-nitrophenol-induced photoluminescence quenching of MoS2 QDs. The high probability of resonance energy transfer (RET) stems from the spectral overlap of MoS2 QD emission spectra and the absorption spectra of p-NP. The high value of the Stern-Volmer constant (KSV = 3.73 × 104 M-1) suggests the efficient quenching of MoS2 QDs by MP in the course of the ET process.... 

    Visual recognition of tryptophan enantiomers using chiral self assemblies of quantum dots

    , Article ACS Applied Nano Materials ; 2021 ; 25740970 (ISSN) Fahimi Kashani, N ; Jafar Nezhad Ivrigh, Z ; Bigdeli, A ; Hormozi Nezhad, M.R ; Sharif University of Technology
    American Chemical Society  2021
    Abstract
    Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral... 

    Visual recognition of tryptophan enantiomers using chiral self assemblies of quantum DOTS

    , Article ACS Applied Nano Materials ; Volume 5, Issue 1 , 2022 , Pages 1460-1471 ; 25740970 (ISSN) Fahimi-Kashani, N ; Jafar Nezhad Ivrigh, Z ; Bigdeli, A ; Hormozi Nezhad, M. R ; Sharif University of Technology
    American Chemical Society  2022
    Abstract
    Discrimination of chiral targets is generally achieved with chiral nanomaterials. However, the limited number of intrinsic chiral nanostructures as well as their complex synthesis procedure has led to the production of chirality-induced nanomaterials as alternatives. Chirality can be induced in nanomaterials by either chirality transfer or the formation of chiral assemblies. Using the latter approach, in this work, we have provided chiral supramolecular assemblies of CdTe quantum dots (QDs) from achiral starting materials. CTAB-QD assemblies showed chiroptical activities, and their orange emission in combination with the blue emission of carbon dots was utilized as a ratiometric chiral... 

    Ratiometric fluorescent nanoprobes for visual detection: Design principles and recent advances - A review

    , Article Analytica Chimica Acta ; Volume 1079 , 2019 , Pages 30-58 ; 00032670 (ISSN) Bigdeli, A ; Ghasemi, F ; Abbasi Moayed, S ; Shahrajabian, M ; Fahimi Kashani, N ; Jafarinejad, S ; Farahmand Nejad, M. A ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Elsevier B.V  2019
    Abstract
    Signal generation techniques for visual detection of analytes have received a great deal of attention in various sensing fields. These approaches are considered to be advantageous when instrumentation cannot be employed, such as for on-site assays, point-of-care tests, and he althcare diagnostics in resource-constrained areas. Amongst various visual detection approaches explored for non-invasive quantitative measurements, ratiometric fluorescence sensing has received particular attention as a potential method to overcome the limitations of intensity-based probes. This technique relies on changes in the intensity of two or more emission bands (induced by an analyte), resulting in an effective... 

    Optical nanoprobes for chiral discrimination

    , Article Analyst ; Volume 145, Issue 20 , 2020 , Pages 6416-6434 Bigdeli, A ; Ghasemi, F ; Fahimi Kashani, N ; Abbasi Moayed, S ; Orouji, A ; Jafar Nezhad Ivrigh, Z ; Shahdost Fard, F ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Royal Society of Chemistry  2020
    Abstract
    Chiral discrimination has always been a hot topic in chemical, food and pharmaceutical industries, especially when dealing with chiral drugs. Enantiomeric recognition not only leads to better understanding of the mechanism of molecular recognition in biological systems, but may further assist in developing useful molecular devices in biochemical and pharmaceutical studies. By emerging nanotechnology and exploiting nanomaterials in sensing applications, a great deal of attention has been given to the design of optical nanoprobes that are able to discriminate enantiomers of chiral analytes. This review explains how engineering nanoparticles (NPs) with desired physicochemical properties allows... 

    Nanoparticle-based optical sensor arrays

    , Article Nanoscale ; Volume 9, Issue 43 , 2017 , Pages 16546-16563 ; 20403364 (ISSN) Bigdeli, A ; Ghasemi, F ; Golmohammadi, H ; Abbasi Moayed, S ; Nejad, M. A. F ; Fahimi-Kashani, N ; Jafarinejad, S ; Shahrajabian, M ; Hormozi-Nezhad, M. R ; Sharif University of Technology
    2017
    Abstract
    As in many other methods that have integrated nanoparticles (NPs), the chemical nose/tongue strategy has also progressed greatly since the entrance of NPs into this field. The fascinating tunable physicochemical properties of NPs have made them powerful candidates for array-based sensing platforms and have enabled the development of real-time, sensitive and portable systems that are able to target complex mixtures of analytes. In particular, the unique optical properties of NPs have a key role in providing promising array-based sensing approaches. This review will describe the main aspects and processes of most common NP-based optical sensor arrays. The fundamental steps in the design of a... 

    From black and white to yin and yang: exploring the management of tensions in social enterprises

    , Article Journal of Social Entrepreneurship ; 2021 ; 19420676 (ISSN) Sarhangi, R ; Mashayekhi, A. N ; Souzanchi Kashani, E ; Sharif University of Technology
    Routledge  2021
    Abstract
    Social enterprises are organisations comprised of two conflicting logics: social and commercial. However, simultaneous commitment to both logics often leads to tensions, making social enterprises fragile organisations at the risk of mission drift. The extant literature on hybridity highlights two important overall strategies–integration and differentiation - for managing tensions. However, integration or differentiation alone can create additional problems, which is especially true in the case of differentiation, creating a situation comparable to black and white, with a salient faultline and heated conflicts. In this inductive qualitative case study, responding to the recent call in the... 

    Production of Copper-Graphene Nanocomposites Via Molecular Level Mixing, Evaluation of the Effect of Some Processing Parameters on Micro-Structure and Physical-Mechanical Properties

    , M.Sc. Thesis Sharif University of Technology Fahimi, Negar (Author) ; Abachi, Parvin (Supervisor)
    Abstract
    This research aimed at production of Cu-rGO via the combination of Molecular-Level-Mixing (MLM) method and powder metallurgy route (PM). First, Cu-GO composite powder was produced via MLM method. Subsequently, the resultant powder was mixed with electrolytic copper powder.Synthesis process included adjustment of the solution containing copper sulfate and 2Na.EDTA using NaOH solution. In the next step, GO suspension was added to the aforementioned solution. Finally, reduction of copper powder and formation of nanocomposite powder completed via the addition of Sodium Borohydrate. Nanocomposite powder was washed and dried in vacuum oven in 70˚C. GO reduction process took place using a tube... 

    The role of powder preparation route on physical and mechanical properties of Cu-rGO bulk nanocomposites

    , Article Materials Today Communications ; Volume 28 , 2021 ; 23524928 (ISSN) Fahimi, N ; Abachi, P ; Sharif University of Technology
    Elsevier Ltd  2021
    Abstract
    To study the effect of the production method on physical and mechanical properties of Cu-rGO nanocomposites, nanocomposite powder samples with rGO content of 0.25–1 wt.% were prepared via combined routes of molecular-level mixing (MLM) and powder metallurgy (PM). Spark plasma sintering (SPS) was applied to consolidate nanocomposite powders with better control on the grain size. According to the specific electrical resistivity measurements, microhardness, and pin-on-disk wear tests, the sample with 0.5 wt.% rGO comprised the best overall properties. For assessment, samples containing 0.5 wt.% rGO were also produced via PM and MLM routes, separately. The physical and mechanical properties of... 

    Development of a colorimetric sensor array based on monometallic and bimetallic nanoparticles for discrimination of triazole fungicides

    , Article Analytical and Bioanalytical Chemistry ; April , 2021 ; 16182642 (ISSN) Kalantari, K ; Fahimi Kashani, N ; Hormozi Nezhad, M. R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2021
    Abstract
    Due to the widespread use of pesticides and their harmful effects on humans and wildlife, monitoring their residual amounts in crops is critically essential but still challenging regarding the development of high-throughput approaches. Herein, a colorimetric sensor array has been proposed for discrimination and identification of triazole fungicides using monometallic and bimetallic silver and gold nanoparticles. Aggregation-induced behavior of AgNPs, AuNPs, and Au-AgNPs in the presence of four triazole fungicides produced a fingerprint response pattern for each analyte. Innovative changes to the metal composition of nanoparticles leads to the production of entirely distinct response patterns... 

    Development of a colorimetric sensor array based on monometallic and bimetallic nanoparticles for discrimination of triazole fungicides

    , Article Analytical and Bioanalytical Chemistry ; Volume 414, Issue 18 , 2022 , Pages 5297-5308 ; 16182642 (ISSN) Kalantari, K ; Fahimi Kashani, N ; Hormozi Nezhada, M. R ; Sharif University of Technology
    Springer Science and Business Media Deutschland GmbH  2022
    Abstract
    Due to the widespread use of pesticides and their harmful effects on humans and wildlife, monitoring their residual amounts in crops is critically essential but still challenging regarding the development of high-throughput approaches. Herein, a colorimetric sensor array has been proposed for discrimination and identification of triazole fungicides using monometallic and bimetallic silver and gold nanoparticles. Aggregation-induced behavior of AgNPs, AuNPs, and Au-AgNPs in the presence of four triazole fungicides produced a fingerprint response pattern for each analyte. Innovative changes to the metal composition of nanoparticles leads to the production of entirely distinct response patterns... 

    Nanoparticle-based optical sensor arrays

    , Article Nanoscale ; v. 9 , 2017 , pages 16546 – 16563 ; 2040-3364 Hormozi-Nezhad, M. R ; Bigdeli, Arafeh ; Ghasemi, Forough ; Golmohammadi, Hamed ; Abbasi-Moayed, Samira ; Farahmand Nejad, M. Amin ; Fahimi-Kashani, Nafiseh ; Jafarinejad, Somayeh ; Shahrajabian, Maryam ; Sharif University of Technology
    Royal Society of Chemistry  2017
    Abstract
    As in many other methods that have integrated nanoparticles (NPs), the chemical nose/tongue strategy has also progressed greatly since the entrance of NPs into this field. The fascinating tunable physicochemical properties of NPs have made them powerful candidates for array-based sensing platforms and have enabled the development of real-time, sensitive and portable systems that are able to target complex mixtures of analytes. In particular, the unique optical properties of NPs have a key role in providing promising array-based sensing approaches. This review will describe the main aspects and processes of most common NP-based optical sensor arrays. The fundamental steps in the design of a...