Search for: biosensors
Total 116 records
Article Journal of Bioresources and Bioproducts ; Volume 6, Issue 3 , 2021 , Pages 215-222 ; 23699698 (ISSN) ; Rabiee, N ; Seidi, F ; Farasati Far, B ; Bagherzadeh, M ; Lima, E. C ; Rabiee, M ; Sharif University of Technology
KeAi Communications Co 2021
A one-pot synthesis method was conceptualized and implemented to develop green carbon-based nanocomposites working as biosensors. Porphyrin was synthesized to adorn the surface of nanocomposites making them highly sensitive for giving rise to π-π interactions between the genetic materials, proteins and porphyrin rings. The hydrogen bond formed between the proteins (analytes) and the nitrogen in the porphyrin structure as well as the surface hydroxyl groups was equally probable. In this context, different forms of porphyrins were incorporated to explore the interrelationship between the surface morphology and the ability of detection of genetic material and/or proteins by the aid of the...
M.Sc. Thesis Sharif University of Technology ; Parsafar, Gholamabbas ; Tafazzoli, Mohsen ; Ejtehadi, Mohammad Reza
In this project, the behavior of single strand DNA (ssDNA) that is end-tethred to surface (surface is covered with an layer of mercaptohexane ) through the Monte Carlo simulation has been investigated. To understand this behavior, a ssDNA has been studied through freely jointed chain (FJC) model with electrostatic, base paring, and base-pair stacking interaction. The concentration of sodium chloride salt in solution is 1 mM and the applied surface potential is -1.5 - +0.25 V. Computational results show that the ssDNA chain can have the following configurations: 1) “very closed”, 2) “closed”, and 3) “open” that considering the amount of energy, the mentioned configurations can be compared...
Ionic liquid/graphene oxide as a nanocomposite for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase, Article Journal of Solid State Electrochemistry ; Vol. 17, Issue 1 , January , 2013 , pp 183-189 ; ISSN: 1432-8488 ; Ghasemi, S. (Shahnaz) ; Ghourchian, H. (Hedayatollah) ; Gholami, M. R. (Mohammad Reza) ; Sharif University of Technology
By combination of 1-ethyl-3-methyl immidazolium ethyl sulfate as a typical room temperature ionic liquid (IL) and graphene oxide (GO) nanosheets, a nanocomposite was introduced for improving the direct electrochemistry and electrocatalytic activity of glucose oxidase (GOx). The enzyme on the IL–GO-modified glassy carbon electrode exhibited a quasireversible cyclic voltammogram corresponding to the flavine adenine dinucleotide/FADH2 redox prosthetic group of GOx. At the scan rate of 100 mV s−1, the enzyme showed a peak-to-peak potential separation of 82 mV and the formal potential of −463 mV (vs Ag/AgCl in 0.1 M phosphate buffer solution, pH 7.0). The kinetic parameters of the charge transfer...
Article Electroanalysis ; Volume 25, Issue 6 , 2013 , Pages 1373-1380 ; 10400397 (ISSN) ; 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,...
A turn-on graphene quantum dot and graphene oxide based fluorometric aptasensor for the determination of telomerase activity, Article Microchimica Acta ; Volume 186, Issue 12 , 2019 ; 00263672 (ISSN) ; Bagheri, H ; Norouzian, D ; Sharif University of Technology
Springer-Verlag Wien 2019
A turn-on fluorometric assay is described for determination of the activity of enzyme telomerase. For this purpose, graphene quantum dots (GQDs) were first modified with the telomeric sequence (5′-amino-AATCCGTCGAGCAGAGTT-3′) via a condensation reaction. Injection of graphene oxide causes instant quenching of the blue fluorescence of the GQDs. Addition of cell extract containing telomerase, triggers the extension of telomer via addition of specific sequence (TTAGGG)n to its 3′ end. Fluorescence, best measured at excitation/emission wavelengths of 390/446 nm, is subsequently restored due to folding of the extended telomeric sequence into G-quadruplex structure. The method was applied to the...
Quick, single-frequency dielectric characterization of blood samples of pediatric cancer patients by a cylindrical capacitor: Pilot study, Article Electronics (Switzerland) ; Volume 9, Issue 1 , 2020 ; Ahmadian, M. T ; Ghanbarzadeh Dagheyan, A ; Sharif University of Technology
MDPI AG 2020
In this paper, as an application in biometrics, the electrical capacitance of normal and cancerous blood samples is experimentally determined in order to test the null hypothesis that the electrical capacitance of the two samples differs. The samples taken from healthy donors and patients diagnosed with different types of hematologic cancer are examined by a cylindrical capacitor with blood as its dielectric. The capacitance of these samples is measured at room temperature and a single frequency of 120 Hz, well below the frequency where β-dispersion starts, using a simple LCR meter device. The measurements indicate that the capacitance of the blood increases under applied electric field for...
Article European Journal of Clinical Microbiology and Infectious Diseases ; 2020 ; Dowlatshahi, S ; Abdekhodaie, M. J ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH 2020
Coronaviruses are a group of envelop viruses which lead to diseases in birds and mammals as well as human. Seven coronaviruses have been discovered in humans that can cause mild to lethal respiratory tract infections. HCoV-229E, HCoV-OC43, HCoV-NL63, and HCoV-HKU1 are the low-risk members of this family and the reason for some common colds. Besides, SARS-CoV, MERS-CoV, and newly identified SARS-CoV-2, which is also known as 2019-nCoV, are the more dangerous viruses. Due to the rapid spread of this novel coronavirus and its related disease, COVID-19, a reliable, simple, fast, and low-cost detection method is necessary for patient diagnosis and tracking worldwide. Human coronaviruses detection...
Development of a sensitive diagnostic device based on zeolitic imidazolate frameworks-8 using ferrocene-graphene oxide as electroactive indicator for pseudomonas aeruginosa detection, Article ACS Sustainable Chemistry and Engineering ; Volume 7, Issue 15 , 2019 , Pages 12760-12769 ; 21680485 (ISSN) ; Ranjbar, S ; Sharif University of Technology
American Chemical Society 2019
Since Gram-negative bacteria have a predominant role in nosocomial infections, there are high demands to develop a fast and sensitive method for diagnosis of bacteria in clinical samples. To address this challenge, we designed a novel electrochemical biosensor based on aptamers immobilized in engineered zeolitic imidazolate Framework-8 (ZIFs-8) via EDC-NHS chemistry. Cyclic voltammetry and electrochemical impedance spectroscopy techniques were conducted to monitor the electrochemical characterization. With respect to unique π-πinteractions between aptamer and graphene oxide (GO), the differential pulse voltammetry technique was applied with ferrocene-graphene oxide (Fc-GO) as an...
M.Sc. Thesis Sharif University of Technology ; Kalhor, Hamid Reza
The most important factor in protein's function and its 3D structure is folding. Misfolding or native folding perturbation in some peptides and proteins force them get into amyloid fibril aggregation. It has been observed that these aggregations are the cause of some debilitative diseases especially ones that are related to aging like Alzheimer disease, Hantington's disease, typeII diabets etc. Recently it has been shown that specific regions in human catalase protein interact with some amyloid fibrils, such as Aß, IAPP, PrP etc. Inteins are self-splicing protein enzymes, which excise themselves from the mature protein and join the two flanking adjacent sequences by a new peptide bond in a...
Quantitative determination of linear alkylbenzene sulfonate (LAS) concentration and simultaneous power generation in a microbial fuel cell-based biosensor, Article Journal of Cleaner Production ; Volume 294 , 2021 ; 09596526 (ISSN) ; Vahabzadeh, F ; Mardanpour, M. M ; Sharif University of Technology
Elsevier Ltd 2021
Linear alkylbenzene sulfonate (LAS), one of the most widely used synthetic surfactants in laundry detergent industry, is considered a hazardous contaminant in wastewater. In the present study, a microbial fuel cell (MFC) based biosensor is developed to quantitively determine the LAS concentration in wastewater. To do so, the developed MFC is fed with LAS concentration of 60 mg l−1. Finally, a sustained biofilm is formed after almost 34 days and the highest open circuit potential of 425 mV is recorded. The maximum power and current densities of 75 mW m−3 and 663 mA m−3 are obtained, respectively; and the internal resistance of the MFC-based biosensor is calculated to be about 1 kΩ. After 98...
M.Sc. Thesis Sharif University of Technology ; Tabandeh, Mahmoud ; Jahed, Mehran
This research presents an efficient thermal-aware routing protocol based on Shortest Hop Routing algorithms for implanted bi medical sensor network. Implanted biomedical sensor networks provide a major application of sensor networks in the near future. These in-vivo sensor nodes collect desired biometric data and communicate the data wirelessly to a base-station through a multi-hop network. They generate the heat due to wireless communication and circuitry power consumption. A high temperature of the in-vivo nodes for a prolonged period might damage the surrounding tissues. Most of the protocols for sensor networks don’t take the thermal issue as a factor in the routing of packets. In its...
Article Microchimica Acta ; Volume 184, Issue 6 , 2017 , Pages 1729-1737 ; 00263672 (ISSN) ; 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...
Enzymatic biosensing by covalent conjugation of enzymes to 3D-networks of graphene nanosheets on arrays of vertically aligned gold nanorods: application to voltammetric glucose sensing, Article Microchimica Acta ; Volume 185, Issue 3 , 2018 ; 00263672 (ISSN) ; Simchi, A ; Aashuri, H ; Sharif University of Technology
Springer-Verlag Wien 2018
The authors demonstrate efficient direct electron transfer from the enzyme glucose oxidase to vertically aligned gold nanorods with a diameter of ~160 nm and a length of ~2 μm that are covalently linkage to a 3-dimensional network of reduced graphene oxide nanosheets. The assembly can be prepared by a 2-step electrochemical procedure. This hybrid structure holds the enzyme in a favorable position while retaining its functionality that ultimately provides enhanced performance for enzymatic sensing of glucose without utilizing mediators. The nanorod assembly was applied to the voltammetric detection of glucose. Figures of merit include an electrochemical sensitivity of 12 μA·mM−1·cm−2...
M.Sc. Thesis Sharif University of Technology ; Alemzadeh, Iran ; Kalantarian, Asadollah
Wastewater, especially with heavy metal contamination, is a global environmental concern. Numerous techniques have been tested for online controlling and monitoring the concentration of heavy metal ions; yet, there are many challenges in performing these techniques. Biosensor is cheap, easily available, simple, fast, selective, sensitive, and repeatable so it is an excellent alternative for the detection and quantification of hazardous particles in the wastewater. In this study, a Nano biosensor with high detection of copper ions has been fabricated. PEDOT:PSS as a highly conductive polymer is coupled with gold nanoparticles to modify the surface of graphite electrode and results in higher...
Synthesis and Characterization of Hybrids 3D Graphene/gold Nanostructures for Supercapacitors and Electrochemical Biosensors, Ph.D. Dissertation Sharif University of Technology ; Simchi, Abdolreza
Energy conversion and storage as well as life sciences are among the areas of our daily life. Interest in carbon nanomaterials for energy storage systems such as supercapacitors has enormously risen due to their attractive electrical conductivity, chemical inertness, and charge storage capacity. Producing these nanomaterials with a simple, scalable, and cost-effective method is the major problem for commercializing them. The reduction of graphitic oxide is a versatile procedure to prepare 3D graphene. Despite many green methods, the dynamics behind ultrafast thermal graphitization have remained elusive. Here, we demonstrate an effort to understand the graphitization mechanism of graphitic...
Application of Cellulose Nanofibers Coated Quartz Crystal Microbalance (QCM)Biosensor for Amino Acid Detection in Aqueous Media, Ph.D. Dissertation Sharif University of Technology ; Iraji Zad, Azam ; Vossoughi, Manouchehr
Developing a simple, cost effective and accurate detection method for L-lysine (Lys), L-leucine (Leu) and glycine (Gly) as the important analytes in clinical diagnostics, biological processes and food industries is of great interest. Therefore, in the first part of this research, cellulose nanofibrils (CNFs) were coated on a quartz crystal microbalance (QCM) surface by spin coating to achieve a QCM biodetector for Gly. Thus, the two-layer CNFs coating was selected as sensing film and was applied for following experiments. In the next step, the coated QCMs were carefully characterized before and after interaction with Gly using water contact angle (WCA), Fourier transform infrared...
Size and geometry of multielectrode arrays determine the efficiency of electrical interaction with neurons through double-layer capacitance, Article IEEE Sensors Journal ; Volume 19, Issue 8 , 2019 , Pages 2829-2836 ; 1530437X (ISSN) ; Mohammadpour, R ; Vossoughi, M ; Sasanpour, P ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2019
Multielectrode array (MEA) structures are the vital parts in the interface between neural structures and external electronic circuits, both in excitation and detection. As a transducer, the performance of electrodes has direct effect on the quality of the recorded neural signal, as well as induced charge density during the stimulation in neural prosthesis. The size and geometry of the electrode structure have distinct effect on the performance of electrodes accordingly. In this paper, the effect of size and geometry of the electrodes has been investigated in their performance and the impedimetric features of the fabricated electrodes with different structures have been studied. Based on the...
Article Advanced Science ; Volume 7, Issue 5 , 2020 ; Kiaee, K ; Vela Jarquin, D ; De la Garza Hernández, R. L ; Wang, T ; Joshi, S ; Rezaei, Z ; de Melo, B. A. G ; Ge, D ; Mannoor, M. S ; Shin, S. R ; Sharif University of Technology
John Wiley and Sons Inc 2020
Advances in biomanufacturing techniques have opened the doors to recapitulate human sensory organs such as the nose and ear in vitro with adequate levels of functionality. Such advancements have enabled simultaneous targeting of two challenges in engineered sensory organs, especially the nose: i) mechanically robust reconstruction of the nasal cartilage with high precision and ii) replication of the nose functionality: odor perception. Hybrid nasal organs can be equipped with remarkable capabilities such as augmented olfactory perception. Herein, a proof-of-concept for an odor-perceptive nose-like hybrid, which is composed of a mechanically robust cartilage-like construct and a biocompatible...
M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza ; Kariminia, Hamid Reza
In this project, quantification of sulfide ion was investigated based on peroxidase enzyme inhibition. The fungal peroxidase was obtained from the liquid culture of Coprinus cinereus NBRC 30628. Two different biosensing systems were suggested for sulfide ion measurement: (1) An amperometric inhibition peroxidase biosensor proposed for determination of sulfide by in situ bulk polymerization of acrylamide for immobilization of peroxidase on screen-printed carbon electrode. Measurements were performed using phosphate buffer solution as a supporting electrolyte in the presence of hydroquinone as a mediator. Identification method was based on reduction of generation current, caused by hydrolysis...
M.Sc. Thesis Sharif University of Technology ; Roosta Azad, Reza ; Musavi, Abbas
In this research, an amperometric inhibition biosensor for the detection of cyanide has been fabricated by immobilization of the horseradish peroxidase (HRP) on the surface of glassy carbone electrode (GCE). Chitosan/acrylamide was applied for immobilization of HRP on the working electrode. All electrochemical measurement were carried out with three electrode: Ag/AgCl electrode as reference electrode, GCE as working electrode and platinium electrode as counter electrode which immersed in phosphate buffer solution. The amperometric measurement was done at an applied potential of -100 mV versus Ag/AgCl with a scan rate of 100 mV in the presence of hydroquinone as electron mediator and...