Search for: nanosensors
Total 37 records
Design and Construction of Tunneling Spectroscope to Study Reaction of Gas with Porous Silicon Surface, M.Sc. Thesis Sharif University of Technology ; Iraji zad, Azam
Studying the interactions between gas molecules and surface is one of the important issues in the field of sensing. In nanometer scales, it can play a key role in fabricating novel nanosensors. Tunneling spectroscopy, on the other hand, is a powerful method for studying the local electrical properties of surface. Our purpose in this project is to design and construct a local tunneling spectroscope, which is able to probe the effects of adsorption of gas molecules on local density of state (LDOS) in sub-nanometer scales. The designed and constructed local tunneling spectroscope system includes a small chamber, which is isolated from any vibrations by means of a set of dampers. In the main...
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...
Application of electrostatically actuated carbon nanotubes in nanofluidic and bio-nanofluidic sensors and actuators, Article Measurement: Journal of the International Measurement Confederation ; Volume 73 , September , 2015 , Pages 127-136 ; 02632241 (ISSN) ; Rastgoo, A ; Ahmadian, M. T ; Sharif University of Technology
The paper investigates the effects of fluid flow on the static and dynamic behaviors of electrostatically actuated carbon nanotubes using nonlocal elasticity theory. The influences of various parameters of fluid flow including fluid viscosity, velocity, mass and temperature on the mechanical behaviors of the carbon nanotubes under static and step DC voltages are studied using this theory. The results computed from the nonlocal elasticity theory are compared with those estimated using the classical elasticity theorem and the outcomes demonstrate the applicability of the electrostatically actuated carbon nanotubes as nano sensors and nano actuators in nanofluidic systems. The nanosystem can be...
Numerical Investigation of Off-axis translocation, Shape, and the Electrical Charge of a Nanoparticle in the Nanofluidic Conduit, M.Sc. Thesis Sharif University of Technology ; Taghipoor, Mojtaba
The advent of nanopore-based sensors based on resitive pulse sensing gave rise to a remarkable breakthrough in the detection and characterization of nanoscale species. The sensors can detect the species’concentration, size, and charge using the resistive pulse characteristics. Some strong correlations have been reported between the resitive pulse characteristics and the particle’s geometrical and physical properties. These correlations are commonly used to obtain information about the particles in commercial devices and research setups. The correlations, however, do not consider the simultaneous effect of influential factors such as particle shape, charge, and off-axis translocation, which...
Computational investigation of graphene behavior under differential water pressure and possible mass transfer influences, Article ASME 2016 5th International Conference on Micro/Nanoscale Heat and Mass Transfer, MNHMT 2016, 4 January 2016 through 6 January 2016 ; Volume 2 , 2016 ; 9780791849668 (ISBN) ; Darbandi, M ; Saidi, M.S ; Heat Transfer Division ; Sharif University of Technology
American Society of Mechanical Engineers 2016
Because of its unique properties, graphene has attracted the attentions of many academic research groups and recently, the industry. One of the promising applications of the graphene is in micro/nano-sensors, e.g. using it as a pressure sensor. To use it in mechanical-based nano-sensors, it is very important to investigate the mechanical behavior of the nano-sized graphene sheet and its sensitivity to the medium changes applied on its faces. In this work, we use the molecular dynamics MD method and simulate the behavior of graphene sheet under differential water pressure influences. In this regard, a square straight monolayer graphene sheet is placed as a separator diaphragm between two...
Article ASME 2007 International Mechanical Engineering Congress and Exposition, IMECE 2007, 11 November 2007 through 15 November 2007 ; Volume 11 , 2007 , Pages 99-104 ; 079184305X (ISBN) ; Ahmadian, M. T ; Vafai, A ; ASME ; Sharif University of Technology
American Society of Mechanical Engineers (ASME) 2007
Molecular structural mechanics is implemented to model vibrational behavior of defect free single-layered graphene sheets (SLGSs) at constant temperature. To mimic these two-dimensional layers, zigzag and armchair models with cantilever and bridge boundary conditions are adopted. Fundamental frequencies of these nano structures are calculated, and it is perceived that they are independent of the chirality and aspect ratio. Effects of point mass and atomistic dust on the fundamental frequencies are also considered in order to investigate the possibility of using SLGSs as sensors. Results of exhibit the principle frequencies are highly sensitive to the added mass in the order of 10-6 fg....
Article Journal of Micro-Bio Robotics ; 2021 ; 21946418 (ISSN) ; Jalili, N ; Ahmadian, M. T ; Sharif University of Technology
Springer Science and Business Media Deutschland GmbH 2021
Micro/Nano mechatronic systems might be defined as systems that include nano- or micro-scale components. These components can be sensors, actuators, and/or physical structures. Furthermore, the high-precision control laws for such small scales are important to ensure stability, accuracy, and precision in these systems. In this writing, four categories of such small-scale systems are considered by providing multifarious novel or key examples from the literature: control engineering and modeling, design and fabrication, measurement engineering, and sensor/actuator development. The applications discussed in the examples vary from nano-positioners, crucial in systems such as atomic force...
Article IEEE Transactions on Nanobioscience ; Volume 18, Issue 2 , 2019 , Pages 103-116 ; 15361241 (ISSN) ; Ahmadzadeh, A ; Wicke, W ; Jamali, V ; Schober, R ; Nasiri Kenari, M ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc 2019
In this paper, we propose using mobile nanosensors (MNSs) for early stage anomaly detection. For concreteness, we focus on the detection of cancer cells located in a particular region of a blood vessel. These cancer cells produce and emit special molecules, so-called biomarkers, which are symptomatic for the presence of anomaly, into the cardiovascular system. Detection of cancer biomarkers with conventional blood tests is difficult in the early stages of a cancer due to the very low concentration of the biomarkers in the samples taken. However, close to the cancer cells, the concentration of the cancer biomarkers is high. Hence, detection is possible if a sensor with the ability to detect...
Vibrational behavior of defective and repaired carbon nanotubes under thermal loading: A stochastic molecular mechanics study, Article Mechanics of Materials ; Volume 163 , 2021 ; 01676636 (ISSN) ; Moradi, K ; Zeraati, A. S ; Hosseinabadi, H. G ; Sharif University of Technology
Elsevier B.V 2021
Carbon nanotubes (CNTs) are promising candidates for high-resolution mass nanosensors owing to their unique vibrational behavior. The structural characteristic (e.g. defect type and density) and working temperature have a significant effect on the natural frequency of CNT-based sensors. Herein, a stochastic approach based on novel finite element and molecular mechanics simulations is implemented to model the effect of temperature and structural characteristics of single-wall CNTs including defects (vacancy defect with different densities) and chirality (zigzag and armchair) on their vibrational behavior. The results show that the vacancy defects exert a significant deterioration of the...
Article ASME International Mechanical Engineering Congress and Exposition, Proceedings (IMECE) ; Volume 2 , 2012 , Pages 193-201 ; 9780791845189 (ISBN) ; Ahmadian, M. T ; Sharif University of Technology
Nano-micro grippers are able to pick-transport-place the micro or nanometer -sized materials, such as manipulation of biological cells or DNA molecules in a liquid medium. This paper proposes a novel monolithic nano-micro gripper structure with two axis piezoresistive force sensor which its resolution is under nanoNewton. The results of the study have been obtained by the simulation of the proposed gripper structure in Matlab software. Motion of the gripper arm is produced by a voice coil actuator. The behavior of the cell has been derived using the assumptions in the literatures. Moreover, two simple PID controllers, one for control of the gripper motion and another for control of the force...
Active vibration control of a cmos-mems nano-newton capacitive force sensor for bio application using PZT, Article Advanced Materials Research, San Diego, CA ; Volume 628 , 2013 , Pages 317-323 ; 10226680 (ISSN) ; 9783037855706 (ISBN) ; Selkghafari, A ; Zabiholah, A ; Meghdari, A ; Sharif University of Technology
This paper reports the design of an optimal controller to prevent suppressvertical vibration due to undesired out of plane excitations generated by environment or gripper during manipulation for a CMOS-MEMS Nano-Newton capacitive force sensor applied for biomedical applications. Undesired out of plane excitations generated by environment or gripper during manipulation is the most prevalent source of vertical vibration in this type of sensors. To suppress the vibrational movement a PZT 5A is used as actuation mechanism. Discrete element method DEM model and Modal analysis were used to find dominant natural frequencies and mode shape vectors. To eliminate out of plane excitation an optimal...
Article 15th IEEE International Conference on Nanotechnology, 27 July 2015 through 30 July 2015 ; 2015 , Pages 45-50 ; 9781467381550 (ISBN) ; Hassan, M ; Chou, C. T ; Bayat, S ; Nanotechnology Council ; Sharif University of Technology
Institute of Electrical and Electronics Engineers Inc
Wireless Nano-scale Sensor Networks (WNSNs) are very simple and energy restricted networks that operate over terahertz band ranging from 0.1-10 THz, which faces significant molecular absorption noise and attenuation. Given these challenges, reliability, energy efficiency, and simplicity constitute the main criteria in designing communication protocols for WNSNs. Due to its simplicity and energy efficiency, carrier-less pulse based modulation is considered the best candidate for WNSNs. In this paper, we compare the performance of four different carrier-less modulations, PAM, OOK, PPM, and BPSK, in the context of WNSNs operating within the terahertz band. Our study shows that although BPSK is...
Article Nano Communication Networks ; Volume 9 , 2016 , Pages 43-57 ; 18787789 (ISSN) ; Hassan, M ; Chou, C. T ; Ebrahimi Warkiani, M ; Sharif University of Technology
Elsevier B.V 2016
We characterize terahertz wireless channels for extracting data from nanoscale sensors deployed within human lungs. We discover that the inhalation and exhalation of oxygen and carbon dioxide causes periodic variation of the absorption coefficient of the terahertz channel. Channel absorption drops to its minimum near the end of inhalation, providing a window of opportunity to extract data with minimum transmission power. We propose an algorithm for nanosensors to estimate the periodic channel by observing signal-to-noise ratio of the beacons transmitted from the data sink. Using real respiration data from multiple subjects, we demonstrate that the proposed algorithm can estimate the minimum...
Geometrical influence of a deposited particle on the performance of bridged carbon nanotube-based mass detectors, Article Physica E: Low-Dimensional Systems and Nanostructures ; Volume 94 , 2017 , Pages 31-46 ; 13869477 (ISSN) ; Ceballes, S ; Abdelkefi, A ; Sharif University of Technology
A nonlocal continuum-based model is derived to simulate the dynamic behavior of bridged carbon nanotube-based nano-scale mass detectors. The carbon nanotube (CNT) is modeled as an elastic Euler-Bernoulli beam considering von-Kármán type geometric nonlinearity. In order to achieve better accuracy in characterization of the CNTs, the geometrical properties of an attached nano-scale particle are introduced into the model by its moment of inertia with respect to the central axis of the beam. The inter-atomic long-range interactions within the structure of the CNT are incorporated into the model using Eringen's nonlocal elastic field theory. In this model, the mass can be deposited along an...
New efficient inorganic-organic nanofibers electrospun membrane for fluorescence detection and removal of mercury (II) ions, Article Journal of Molecular Structure ; Volume 1179 , 2019 , Pages 242-251 ; 00222860 (ISSN) ; Poush, M. K ; Ahmed, M ; Parsaee, Z ; Sharif University of Technology
Elsevier B.V 2019
In this study, a new inorganic-organic nano fibrous membrane (PTSNFM) has been fabricated via immobilization of carbazol-based Schiff base (S) into a polyvinyl alcohol (PVA) - tetraethyl orthosilicate (TEOS) polymeric support using the electrospinning method. PTSNFM has been used as an optode to detect and remove of mercury (II) ions. The characterization of PTSNFM has been fully carried out using different methods including FE-SEM, TEM, AFM, viscosity, surface tension and conductivity. FE-SEM and FT-IR analysis demonstrated the binding of Hg (II) to the PTSNFM via chelating of Hg (II) to the Schiff base ligand. PTSNFM can detect Hg (II) in the dynamic range of 0.020–0.50 ng/mL, with the LOD...
A novel sensitive aptamer-based nanosensor using rGQDs and MWCNTs for rapid detection of diazinon pesticide, Article Journal of Environmental Chemical Engineering ; Volume 9, Issue 1 , 2021 ; 22133437 (ISSN) ; Bozorg, A ; Faridbod, F ; Vossoughi, M ; Sharif University of Technology
Elsevier Ltd 2021
An optical apta-nanosensor was designed and developed based on reduced graphene quantum dots (rGQDs) and multi-walled carbon nanotubes (MWCNTs) and applied for the selective detection of diazinon as one of the most widely used organophosphorus pesticides. Considering the GQDs and rGQDs high fluorescence emission and optical stability, efficient optical transducers could be designed and precise detection methods could be developed based on such transducers. Herein, by using rGQDs, diazinon specific aptamer, and MWCNTs, a simple economical fluorescence method has been introduced to detect and measure diazinon with the detection limit of 0.4 nM (0.1 μg/L) in the range of 4-31 nM, meeting the...
Dynamics of Magnetic Nanoparticles in Biologically Inspired Flows under Effect of Electric and Magnetic Fields with Application in Epilepsy Detection, Ph.D. Dissertation Sharif University of Technology ; Alasty, Aria ; Ghaffarzadeh, Ebrahim ; Shamloo, Amir
This thesis presents my Ph.D. research study focusing on the dynamic analysis of magnetic nanoparticles (MNPs) for epilepsy and blood-brain barrier (BBB) applications. In this analysis, we took into account various parameters including the magnetic field, fluid behavior, geometry and material of MNPs. Based on this computational study, the generated magnetic field in epileptic foci results in the aggregation of nanoparticles. This may offer the advantage of using MNPs as a Magnetic Resonance Imaging (MRI) contrast agent. Furthermore, in this study, we also demonstrated and discussed the advantage of MNPs for crossing BBB using the external magnetic field. The outcome of this research project...
Application of elastically supported single-walled carbon nanotubes for sensing arbitrarily attached nano-objects, Article Current Applied Physics ; Volume 13, Issue 1 , 2013 , Pages 107-120 ; 15671739 (ISSN) ; Ghaffari, H ; Mehri, B ; Sharif University of Technology
The potential application of SWCNTs as mass nanosensors is examined for a wide range of boundary conditions. The SWCNT is modeled via nonlocal Rayleigh, Timoshenko, and higher-order beam theories. The added nano-objects are considered as rigid solids, which are attached to the SWCNT. The mass weight and rotary inertial effects of such nanoparticles are appropriately incorporated into the nonlocal equations of motion of each model. The discrete governing equation pertinent to each model is obtained using an effective meshless technique. The key factor in design of a mass nanosensor is to determine the amount of frequency shift due to the added nanoparticles. Through an inclusive parametric...
Article Technical Proceedings of the 2011 NSTI Nanotechnology Conference and Expo, NSTI-Nanotech 2011, 13 June 2011 through 16 June 2011, Boston, MA ; Volume 3 , 2011 , Pages 236-239 ; 9781439871386 (ISBN) ; Mohajerzadeh, S ; Janmaleki, M ; Akhavan, O ; Azimi, S ; Clean Technology and Sustainable Industries Organization (CTSI); European Patent Office; Greenberg Traurig; Innovation and Materials Science Institute; Jackson Walker L.L.P ; Sharif University of Technology
The photo-thermal therapy using nano-materials has attracted great attention as an efficient strategy for the next generation of cancer treatments. Recently, photo-thermal therapy based on nano-materials that can be activated by a skin-penetrating NIR (Near Infra Red) irradiation has been suggested as a noninvasive, harmless, and highly efficient therapeutic technique. Graphene nano-layers synthesized by a bio-compatible method, with reduced toxicity, will be a suitable candidate for the photo-thermal therapeutic agent. A significant amount of heat is generated upon excitation with near-infrared light (NIR, 700-1100nm) which is transparent to biological species including skins. In this...
Article Materials Letters ; Volume 65, Issue 9 , 2011 , Pages 1249-1251 ; 0167577X (ISSN) ; Barzegar, S ; Ebrahimi, G. R ; Varahram, N ; Sharif University of Technology
SnO2 is an important functional material having a wide range of applications in gas sensors and optoelectronic devices. There is a great interest for finding new cost-effective and straight-forward methods for production of these particles. In this research, hydrogel thermal decomposition method (HTDM) is used for production of high purity SnO2 nano-particles. Cost effective reactants and green routs of production are the advantages of polysaccharide based hydrogel as starting material for this method. Visual observations indicated that there is very little tendency for agglomeration in the SnO2 nano-particles produced by this method which can be considered as an advantage for this method...