Search for: dna-biosensor
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    Amplified electrochemical DNA sensor based on polyaniline film and gold nanoparticles

    , Article Electroanalysis ; Volume 25, Issue 6 , 2013 , Pages 1373-1380 ; 10400397 (ISSN) Saberi, R. S ; Shahrokhian, S ; Marrazza, G ; Sharif University of Technology
    In this work, an electrochemical DNA biosensor, based on a dual signal amplified strategy by employing a polyaniline film and gold nanoparticles as a sensor platform and enzyme-linked as a label, for sensitive detection is presented. Firstly, polyaniline film and gold nanoparticles were progressively grown on graphite screen-printed electrode surface via electropolymerization and electrochemical deposition, respectively. The sensor was characterized by scanning electron microscopy (SEM), cyclic voltammetry and impedance measurements. The polyaniline-gold nanocomposite modified electrodes were firstly modified with a mixed monolayer of a 17-mer thiol-tethered DNA probe and a spacer thiol,... 

    Impedimetic biosensor for the DNA of the human papilloma virus based on the use of gold nanosheets

    , Article Microchimica Acta ; Volume 184, Issue 6 , 2017 , Pages 1729-1737 ; 00263672 (ISSN) Karimizefreh, A ; Aghakhani Mahyari, F ; VaezJalali, M ; Mohammadpour, R ; Sasanpour, P ; Sharif University of Technology
    The authors describe an impedimetric method for the quantitation of the DNA of the human papilloma virus (HPV) type 16. A glassy carbon electrode (GCE) was modified with gold nanosheets and is shown to be superior to a common gold disk electrode. A single-stranded 25mer oligonucleotide (ssDNA) acting as the probe DNA was immobilized via its thiolated 5′ end on both electrodes. After hybridization with target (analyte) DNA, electrochemical impedance spectra were acquired in the presence of hexacyanoferrate as a redox marker. The sensor can distinguish between complementary, non-complementary and single base pair mismatches of HPV ssDNA. At a 1 mM hexacyanoferrate concentration, the biosensors... 

    A simple label-free electrochemical DNA biosensor based on carbon nanotube-DNA interaction

    , Article RSC Advances ; Volume 6, Issue 19 , 2016 , Pages 15592-15598 ; 20462069 (ISSN) Shahrokhian, S ; Salimian, R ; Kalhor, H. R ; Sharif University of Technology
    Royal Society of Chemistry  2016
    A simple platform based on a hairpin oligonucleotide switch and multi-walled carbon nanotubes (MWCNTs) for the ultrasensitive detection of specific DNA sequences has been developed. In this approach, the π-stacking interaction of single-strand DNA-MWCNT was employed to construct an electrochemical DNA biosensor. Changes to the surface conductivity, based on the MWCNT replacement, were monitored by using the electrochemical species [Fe(CN)6]3-/4- as a redox probe. Morphological and voltammetric characterizations of the electrode surface were performed using atomic force microscopy (AFM), energy dispersive spectroscopy (EDS), cyclic voltammetry (CV), differential pulse voltammetry (DPV) and... 

    The field effect transistor DNA biosensor based on ITO nanowires in label-free hepatitis B virus detecting compatible with CMOS technology

    , Article Biosensors and Bioelectronics ; Volume 105 , 15 May , 2018 , Pages 58-64 ; 09565663 (ISSN) Shariati, M ; Sharif University of Technology
    Elsevier Ltd  2018
    In this paper the field-effect transistor DNA biosensor for detecting hepatitis B virus (HBV) based on indium tin oxide nanowires (ITO NWs) in label free approach has been fabricated. Because of ITO nanowires intensive conductance and functional modified surface, the probe immobilization and target hybridization were increased strongly. The high resolution transmission electron microscopy (HRTEM) measurement showed that ITO nanowires were crystalline and less than 50 nm in diameter. The single-stranded hepatitis B virus DNA (SS-DNA) was immobilized as probe on the Au-modified nanowires. The DNA targets were measured in a linear concentration range from 1fM to 10 µM. The detection limit of...