Search for: fluorescent-dyes
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    A smartphone-based fluorescent electronic tongue for tracing dopaminergic agents in human urine

    , Article ACS Chemical Neuroscience ; Volume 12, Issue 17 , 2021 , Pages 3157-3166 ; 19487193 (ISSN) Shahdost Fard, F ; Bigdeli, A ; Hormozi Nezhad, M. R ; Sharif University of Technology
    American Chemical Society  2021
    The importance of tracing dopaminergic agents in the progression assessment of Parkinson's disease has boosted the demand for fast, sensitive, and real-time multi-analyte detection. Herein, visual and fingerprint fluorimetric patterns have been created by an optical sensor array to simultaneously detect and discriminate among levodopa, carbidopa, benserazide, and entacapone, as important dopaminergic agents. A dual emissive nanoprobe consisting of red quantum dots and blue carbon dots with an overall pink emission has been fabricated to provide unique emission patterns in the presence of the target analytes. The sensor elements in the array come from it's differential response in the absence... 

    Multiway investigation of interaction between fluorescence labeled DNA strands and unmodified gold nanoparticles

    , Article Analytical Chemistry ; Volume 84, Issue 15 , July , 2012 , Pages 6603-6610 ; 00032700 (ISSN) Akhlaghi, Y ; Kompany Zareh, M ; Hormozi Nezhad, M. R ; Sharif University of Technology
    ACS  2012
    The single stranded DNA can be adsorbed on the negatively charged surface of gold nanoparticles (AuNPs), but the rigid structure of double stranded DNA prevents it from adsorption. Signal of a tagged single stranded DNA will be quenched by the plasmon effect of the AuNP surface after its adsorption. This phenomenon has been used to study the DNA hybridization and interactions of two complementary 21mer oligonucleotides each tagged with a different fluorescent dye in the presence of 13 nm gold nanoparticles. The DNA strands used in this study belong to the genome of HIV. The obtained rank deficient three-way fluorescence data sets were resolved by both PARAFAC and restricted Tucker3 models.... 

    In situ LIF temperature measurements in aqueous ammonium chloride solution during uni-directional solidification

    , Article Experiments in Fluids ; Volume 48, Issue 4 , April , 2010 , Pages 651-662 ; 07234864 (ISSN) Shafii, M. B ; Lum, C. L ; Koochesfahani, M. M ; Sharif University of Technology
    We present in situ whole-field measurements of the temperature field using laser-induced fluorescence in a study of bottom-chilled uni-directional solidification of aqueous ammonium chloride. We utilize a two-color, two-dye, ratiometric approach to address the significant spatial and temporal variations of laser sheet intensity field due to refractive index variations caused by the evolving concentration and temperature fields. In our work we take advantage of two temperature sensitive fluorescent dyes with opposite temperature sensitivities in order to increase the overall sensitivity and temperature resolution of the measurements. The resulting temperature sensitivity (about 4% K-1) is... 

    Identification of catecholamine neurotransmitters using a fluorescent electronic tongue

    , Article ACS Chemical Neuroscience ; Volume 11, Issue 1 , November , 2020 , Pages 25-33 Jafarinejad, S ; Bigdeli, A ; Ghazi Khansari, M ; Sasanpour, P ; Hormozinezhad, M. R ; Sharif University of Technology
    American Chemical Society  2020
    Catecholamine neurotransmitters, specifically, dopamine (DA), epinephrine (EP), and norepinephrine (NE), are known as substantial indicators of various neurological diseases. Developing rapid detection methods capable of simultaneously screening their concentrations is highly desired for early clinical diagnosis of such diseases. To this aim, we have designed an optical sensor array using three fluorescent dyes with distinct emission bands and have monitored variations in their emission profiles upon the addition of DA, EP, and NE in the presence of gold ions. Because of the different reducing power of catecholamines, differently sized gold nanoparticles (GNPs) with different levels of... 

    Fluid particle diffusion through high-hematocrit blood flow within a capillary tube

    , Article Journal of Biomechanics ; Volume 44, Issue 1 , Jan , 2011 , Pages 170-175 ; 00219290 (ISSN) Saadatmand, M ; Ishikawa, T ; Matsuki, N ; Jafar Abdekhodaie, M ; Imai, Y ; Ueno, H ; Yamaguchi, T ; Sharif University of Technology
    Fluid particle diffusion through blood flow within a capillary tube is an important phenomenon to understand, especially for studies in mass transport in the microcirculation as well as in solving technical issues involved in mixing in biomedical microdevices. In this paper, the spreading of tracer particles through up to 20% hematocrit blood, flowing in a capillary tube, was studied using a confocal micro-PTV system. We tracked hundreds of particles in high-hematocrit blood and measured the radial dispersion coefficient. Results yielded significant enhancement of the particle diffusion, due to a micron-scale flow-field generated by red blood cell motions. By increasing the flow rate, the...