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Title: Thermoset polymer-layered silicic acid nanocomposites
Creator: Wang, Zhen
Date: 1997
Collection: Electronic Theses & Dissertations

Title: Structural transitions in nanoscale systems
Creator: Yoon, Mina
Date: 2004
Collection: Electronic Theses & Dissertations

Title: Simulation study of lipid bilayer/nanoparticle interactions
Creator: Musolff, Corey Evan
Date: 2013
Collection: Electronic Theses & Dissertations
Description: A coarse-grained model is used to simulate lipid bilayers (LB) interacting with nanoparticles (NP). Different equilibrium states are observed as the size of the NP is varied along with the interaction strength between the NP and LB. Sufficient attraction causes the NP to become wrapped by the LB. Large NP are able to form pores in the LB. These various outcomes are explained using a continuum theory.The same model is used to simulate pore healing in LB. It is observed that the area of the...
Show moreA coarse-grained model is used to simulate lipid bilayers (LB) interacting with nanoparticles (NP). Different equilibrium states are observed as the size of the NP is varied along with the interaction strength between the NP and LB. Sufficient attraction causes the NP to become wrapped by the LB. Large NP are able to form pores in the LB. These various outcomes are explained using a continuum theory.The same model is used to simulate pore healing in LB. It is observed that the area of the pore decreases linearly with time as explained by Allen-Cahn theory. Bulk properties of the LB can be used to predict the closing time of a pore as well as the amount of charge able to flow through the pore while it is open.
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Title: Sensing and manipulation in a nano-bio environment using atomic force microscopy based robotic system
Creator: Li, Guangyong
Date: 2006
Collection: Electronic Theses & Dissertations

Title: Sensing and actuation of bead-tagged biomaterials on standard CMOS substrates
Creator: Abu-Nimeh, Faisal T.
Date: 2011
Collection: Electronic Theses & Dissertations
Description: Magnetic molecular-level sensing and manipulation are emerging as lab-on-chip platforms. These platforms entail low-cost, low-power, high efficiency, and portable implementations. Biomaterials are usually attached to magnetic beads and used in bio-analysis applications such as sorting, counting, purification, and assembly. Some of the potential applications are 2D biological or artificial tissue assembly at the micro-scale level.Here, we present the design and demonstration of a self...
Show moreMagnetic molecular-level sensing and manipulation are emerging as lab-on-chip platforms. These platforms entail low-cost, low-power, high efficiency, and portable implementations. Biomaterials are usually attached to magnetic beads and used in bio-analysis applications such as sorting, counting, purification, and assembly. Some of the potential applications are 2D biological or artificial tissue assembly at the micro-scale level.Here, we present the design and demonstration of a self-contained device for sensing and manipulating biomaterials tagged with magnetic beads. The core elements of the device consist of all-integrated programmable magnetic coil arrays for pseudo-parallel sensing and actuation, which are capable of maneuvering small (bead-bound) bio-objects individually and larger ones collaboratively. Our design does not require any external magnetic sources. It relies on the magnetic field generated by planar on-chip coil arrays. The coil arrays are selectively and dynamically controlled. Each element, composed of the coil and its logical control circuitry, can detect bio-objects in the order of 1$\mu$m diameter, or manipulate them using eight-level programmable AC or DC magnetic fields. All array sensing and actuation components are shared and multiplexed to reduce the overall imprint. The components are isolated and tuned to work at 900MHz by incorporating high-speed switching (up to 40MHz) for seamless pseudo-parallel execution.In addition, we present a new and unique on-chip biomedical proof-of-concept application. Adopting trends in neuroscience, we employ the magnetic beads to initiate and elongate neuronal axons in vitro on-chip. This application domain will assist in better understanding and studying the process of neuroregeneration, propel future clinical applications, and provide the foundation of techniques needed to wire ``neuronal circuits'' using living cells.
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Title: Segmented nano-force sensor
Creator: Dharuman, Gautham
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Nanoscale force sensors are finding widespread applications in atomic and biological force sensing where forces involved range from zeptonewtons to several nanonewtons. Different methods of nanoscale force sensing based on optical, electrical or purely mechanical schemes have been reported. However, each technique is limited by factors such as large size, low resolution, slow response, force range and alignment issues. In this research, a new device structure which could overcome the above...
Show moreNanoscale force sensors are finding widespread applications in atomic and biological force sensing where forces involved range from zeptonewtons to several nanonewtons. Different methods of nanoscale force sensing based on optical, electrical or purely mechanical schemes have been reported. However, each technique is limited by factors such as large size, low resolution, slow response, force range and alignment issues. In this research, a new device structure which could overcome the above mentioned constraints is studied theoretically and experimentally for the possibility of its application in nano-scale force sensing.
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Title: Robust control of systems with piecewise linear hysteresis
Creator: Edardar, Mohamed Mohamed
Date: 2013
Collection: Electronic Theses & Dissertations
Description: Hysteresis nonlinearity is found in many control system applications such as piezo-actuated nanopositioners. The positioner is represented as a linear system preceded by hysteresis. This hysteresis nonlinearity is usually modeled by operators in order to simulate their effects in the closed-loop system or to use their inverse to compensate for their effects. In order to reduce the hysteresis effect, an approximate inverse operator is used as a feedforward compensator. The first part of our...
Show moreHysteresis nonlinearity is found in many control system applications such as piezo-actuated nanopositioners. The positioner is represented as a linear system preceded by hysteresis. This hysteresis nonlinearity is usually modeled by operators in order to simulate their effects in the closed-loop system or to use their inverse to compensate for their effects. In order to reduce the hysteresis effect, an approximate inverse operator is used as a feedforward compensator. The first part of our work considers driving an upper bound on the inversion error using the hysteresis model. This bound is a function of the input references, which is much less conservative than constant bounds. It is used in designing the closed-loop control systems. The second part is to design feedback controller to achieve the desired performance. Three different methods are used throughout this work and a comparison between them is also provided. First, we use the conventional proportional Integral (PI) control method, which is extensively used in commercial applications. However, in our method we add a feedforward component which improves the performance appreciably. Second, a sliding-mode-control (SMC) scheme is used because it is one of the very powerful nonlinear robust control methods. Other schemes like high gain feedback and Lyapunov redesign have close results to SMC and hence it is not included in this work. The third control is H∞ control. It is a robust linear control method, which deals with uncertainty in the system in an optimal control structure. Unlike the PI controller, the H∞ controller uses the features of the linear plant in the design which allows to accomplish more than the simple PI controller. Mainly, it can shape the closed-loop transfer function of the system to achieve the design objectives. Including the operators in the closed-loop system, makes it hard to obtain explicit solutions of the dynamics using conventional methods. We exploit two features of piezoelectric actuators to provide a complete solution of the tracking error. First, the hysteresis is approximated by a piece-wise linear operator. Second, the linear plant has a large bandwidth which allows using singular perturbation techniques to put the system in a time-scale structure. We show that the slope of a hysteresis loop segment plays an important role in determining the error size. Our analysis also shows how error is affected by increasing the frequency of the reference input. We verify that the accumulation of the error, which is propagating from segment to another is bounded and derive its limit. We provide a comparison between simulation and the analytic expressions of the tracking error at different frequencies. Experimental results are also presented to show the effectiveness of our controllers compared with other techniques.
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Title: Polyelectrolyte multilayer coatings for conductive nanomaterials patterning and anti-wrinkling applications
Creator: Hendricks, Troy Richard
Date: 2008
Collection: Electronic Theses & Dissertations

Title: Physical properties and transformations of low-dimensional systems
Creator: Liu, Dan (Graduate of Michigan State University)
Date: 2019
Collection: Electronic Theses & Dissertations
Description: Evolving from the macroscopic scale to the nanometer scale, inparticular by reducing the dimensionality, fundamental properties(such as electronic and mechanical properties) of certain systemsexhibit dramatic changes, which not only give rise to a wide rangeof emergent phenomena, but also boost technology developmentincluding nanoelectronics, optoelectronics and catalysis. In thisthesis, I utilized combined techniques including densityfunctional theory (DFT), molecular dynamic simulations (MD...
Show moreEvolving from the macroscopic scale to the nanometer scale, inparticular by reducing the dimensionality, fundamental properties(such as electronic and mechanical properties) of certain systemsexhibit dramatic changes, which not only give rise to a wide rangeof emergent phenomena, but also boost technology developmentincluding nanoelectronics, optoelectronics and catalysis. In thisthesis, I utilized combined techniques including densityfunctional theory (DFT), molecular dynamic simulations (MD),continuum elasticity approach, and the tight-binding model toconduct a systematic study on low-dimensional nanostructuresregarding their electronic and mechanical properties as well asunderlying microscopic transformation mechanisms between differentstructural allotropes.First, I briefly introduce the motivation and background of thisthesis. Then, in Chapter 2, I describe the computationaltechniques, mainly the DFT approach, on which most of my thesis isbased.In Chapters 3 and 4, I apply the continuum elasticity method tostudy the phonon spectrum of two-dimensional (2D) andone-dimensional (1D) systems. My results highlight advantages ofthe continuum elasticity approach especially for the flexuralacoustic phonon modes close to the $\Gamma$ point, which areotherwise extremely hard to converge in atomistic calculationsthat use very large supercell sizes.From Chapter 5 to Chapter 7, I focus on allotropes of groupIII, V and VI elements and study boththeir stability and microscopic transformation mechanisms from oneallotrope to another. First, I predicted a stable phosphorus coilstructure, which may form by reconstruction of red phosphorous,and which was synthesized by filling a carbon nanotube withsublimed red phosphorus. Second, I proposed two stable 2Dallotropes of Se and Te. I also suggested and evaluated apromising fabrication approach starting from natural 1D structuresof these elements. After considering low-dimensional chargeneutral systems, I changed my focus to study the effect of netcharge on the equilibrium structure. Considering a heterostructureof alternating electron donor layers an monolayers of boron, Ihave identified previously unknown stable 2D boron allotropes thatmay change their structure under different levels of chargetransfer.From Chapter 8 to Chapter 10, I focus mainly on carbon-basednanomaterials and their properties. In Chapter 8, I proposed a wayto enhance the density of states at the Fermi level in dopedC60 crystals in order to increase their superconductingcritical temperature to room temperature. In Chapter 9, I haveinvestigated a shear instability twisted bilayer graphene usingthe tight binding model. This system is susceptible to very smallstructural changes, since it becomes superconducting in a verynarrow range of twist angles near the 'magic angle'. In Chapter10, I introduced the cause of an unusual negative Poisson ratioand a shape-memory behavior in porous graphene with anartificially designed pattern.In Chapter 11, I finally present general conclusions of my PhDThesis.
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Title: Nanorobotic end-effectors : design, fabrication, and in situ characterization
Creator: Fan, Zheng (Of Michigan State University)
Date: 2015
Collection: Electronic Theses & Dissertations
Description: Nano-robotic end-effectors have promising applications for nano-fabrication, nano-manufacturing, nano-optics, nano-medical, and nano-sensing; however, low performances of the conventional end-effectors have prevented the widespread utilization of them in various fields. There are two major difficulties in developing the end-effectors: their nano-fabrication and their advanced characterization in the nanoscale. Here we introduce six types of end-effectors: the nanotube fountain pen (NFP), the...
Show moreNano-robotic end-effectors have promising applications for nano-fabrication, nano-manufacturing, nano-optics, nano-medical, and nano-sensing; however, low performances of the conventional end-effectors have prevented the widespread utilization of them in various fields. There are two major difficulties in developing the end-effectors: their nano-fabrication and their advanced characterization in the nanoscale. Here we introduce six types of end-effectors: the nanotube fountain pen (NFP), the super-fine nanoprobe, the metal-filled carbon nanotube (m@CNT)-based sphere-on-pillar (SOP) nanoantennas, the tunneling nanosensor, and the nanowire-based memristor. The investigations on the NFP are focused on nano-fluidics and nano-fabrications. The NFP could direct write metallic "inks" and fabricating complex metal nanostructures from 0D to 3D with a position servo control, which is critically important to future large-scale, high-throughput nanodevice production. With the help of NFP, we could fabricate the end-effectors such as super-fine nanoprobe and m@CNT-based SOP nanoantennas. Those end-effectors are able to detect local flaws or characterize the electrical/mechanical properties of the nanostructure. Moreover, using electron-energy-loss-spectroscopy (EELS) technique during the operation of the SOP optical antenna opens a new basis for the application of nano-robotic end-effectors. The technique allows advanced characterization of the physical changes, such as carrier diffusion, that are directly responsible for the device's properties. As the device was coupled with characterization techniques of scanning-trasmission-electron-microscopy (STEM), the development of tunneling nanosensor advances this field of science into quantum world. Furthermore, the combined STEM-EELS technique plays an important role in our understanding of the memristive switching performance in the nanowire-based memristor. The developments of those nano-robotic end-effectors expend the study abilities in investigating the in situ nanotechnology, providing efficient ways in in situ nanostructure fabrication and the advanced characterization of the nanomaterials.
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Title: Multiscale modeling and computation of nano-electronic transistors and transmembrane proton channels
Creator: Chen, Duan
Date: 2010
Collection: Electronic Theses & Dissertations
Description: The miniaturization of nano-scale electronic transistors, such as metal oxide semiconductor field effect transistors (MOSFETs), has given rise to a pressing demand in the new theoretical understanding and practical tactic for dealing with quantum mechanical effects in integrated circuits. In biology, proton dynamics and transport across membrane proteins are of paramount importance to the normal function of living cells. Similar physical characteristics are behind the two subjects, and model...
Show moreThe miniaturization of nano-scale electronic transistors, such as metal oxide semiconductor field effect transistors (MOSFETs), has given rise to a pressing demand in the new theoretical understanding and practical tactic for dealing with quantum mechanical effects in integrated circuits. In biology, proton dynamics and transport across membrane proteins are of paramount importance to the normal function of living cells. Similar physical characteristics are behind the two subjects, and model simulations share common mathematical interests/challenges. In this thesis work, multiscale and multiphysical models are proposed to study the mechanisms of nanotransistors and proton transport in transmembrane at the atomic level.For nano-electronic transistors, we introduce a unified two-scale energy functional to describe the electrons and the continuum electrostatic potential. This framework enables us to put microscopic and macroscopic descriptions on an equal footing at nano-scale. Additionally, this model includes layered structures and random doping effect of nano-transistors.For transmembrane proton channels, we describe proton dynamics quantum mechanically via a density functional approach while implicitly treat numerous solvent molecules as a dielectric continuum. The densities of all other ions in the solvent are assumed to obey the Boltzmann distribution. The impact of protein molecular structure and its charge polarization on the proton transport is considered in atomic details. We formulate a total free energy functional to include kinetic and potential energies of protons, as well as electrostatic energy of all other ions on an equal footing.For both nano-transistors and proton channels systems, the variational principle is employed to derive nonlinear governing equations. The Poisson-Kohn-Sham equations are derived for nano-transistors while the generalized Poisson-Boltzmann equation and Kohn-Sham equation are obtained for proton channels. Related numerical challenges in simulations are addressed: the matched interface and boundary (MIB) method, the Dirichlet-to-Neumann mapping (DNM) technique, and the Krylov subspace and preconditioner theory are introduced to improve the computational efficiency of the Poisson-type equation. The quantum transport theory is employed to solve the Kohn-Sham equation. The Gummel iteration and relaxation technique are utilized for overall self-consistent iterations.Finally, applications are considered and model validations are verified by realistic nano-transistors and transmembrane proteins. Two distinct device congurations, a double-gate MOSFET and a four-gate MOSFET, are considered in our three dimensionalnumerical simulations. For these devices, the current uctuation and voltage threshold lowering effect induced by discrete dopants are explored. For proton transport, a realistic channel protein, the Gramicidin A (GA) is used to demonstrate the performance of the proposed proton channel model and validate the efficiency of the proposed mathematical algorithms. The electrostatic characteristics of the GA channel is analyzed with a wide range of model parameters. Proton channel conductances are studied over a number of applied voltages and reference concentrations. Comparisons with experimental data are utilized to verify our model predictions.
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Title: Modeling and control for micro and nano manipulation
Creator: Wejinya, Uchechukwu C.
Date: 2007
Collection: Electronic Theses & Dissertations

Title: Mathematical modeling and simulation of mechanoelectrical transducers and nanofluidic channels
Creator: Park, Jin Kyoung
Date: 2014
Collection: Electronic Theses & Dissertations
Description: Remarkable advances in nanotechnology and computational approaches enable researchers to investigate physical and biological phenomena in an atomic or molecular scale. Smaller-scale approaches are important to study the transport of ions and/or molecules through ion channels in living organisms as well as exquisitely fabricated nanofluidic channels. Both subjects have similar physical properties and hence they have common mathematical interests and challenges in modeling and simulating the...
Show moreRemarkable advances in nanotechnology and computational approaches enable researchers to investigate physical and biological phenomena in an atomic or molecular scale. Smaller-scale approaches are important to study the transport of ions and/or molecules through ion channels in living organisms as well as exquisitely fabricated nanofluidic channels. Both subjects have similar physical properties and hence they have common mathematical interests and challenges in modeling and simulating the transport phenomena. In this work, we first propose and validate a molecular level prototype for mechanoelectrical transducer (MET) channel in mammalian hair cells.Next, we design three ionic diffusive nanofluidic channels with different types of atomic surface charge distribution, and explore the current properties of each channel. We construct the molecular level prototype which consists of a charged blocker, a realistic ion channel and its surrounding membrane. The Gramicidin A channel is employed to demonstrate the realistic channel structure, and the blocker is a positively charged atom of radius $1.5$\AA\, which is placed at the mouth region of the channel. Relocating this blocker along one direction just outside the channel mouth imitates the opening and closing behavior of the MET channel. In our atomic scale design for an ionic diffusive nanofluidic channel, the atomic surface charge distribution is easy to modify by varying quantities and signs of atomic charges which are equally placed slightly above the channel surface. Our proposed nanofluidic systems constitutes a geometrically well-defined cylindrical channel and two reservoirs of KCl solution. For both the mammalian MET channel and the ion diffusive nanofluidic channel, we employ a well-established ion channel continuum theory, Poisson-Nernst-Planck theory, for three dimensional numerical simulations. In particular, for the nano-scaled channel descriptions, the generalized PNP equations are derived by using a variational formulation and by incorporating non-electrostatic interactions. We utilize several useful mathematical algorithms, such as Dirichlet to Neumann mapping and the matched interface and boundary method, in order to validate the proposed models with charge singularities and complex geometry. Moreover, the second-order accuracy of the proposed numerical methods are confirmed with our nanofluidic system affected by a single atomic charge and eight atomic charges, and further study the channels with a unipolar charge distribution of negative ions and a bipolar charge distribution. Finally, we analyze electrostatic potential and ion conductance through each channel model under the influence of diverse physical conditions, including external applied voltage, bulk ion concentration and atomic charge. Our MET channel prototype shows an outstanding agreement with experimental observation of rat cochlear outer hair cells in terms of open probability. This result also suggests that the tip link, a connector between adjacent stereocilia, gates the MET channel. Similarly, numerical findings, such as ion selectivity, ion depletion and accumulation, and potential wells, of our proposed ion diffusive realistic nanochannels are in remarkable accordance with those from experimental measurements and numerical simulations in the literature. In addition, simulation results support the controllability of the current within a nanofluidic channel.
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Title: In situ sensing and modeling of molecular events at the cellular level
Creator: Yang, Ruiguo
Date: 2014
Collection: Electronic Theses & Dissertations
Description: We developed the Atomic Force Microscopy (AFM) based nanorobot in combination with other nanomechanical sensors for the investigation of cell signaling pathways. The AFM nanorobotics hinge on the superior spatial resolution of AFM in imaging and extends it into the measurement of biological processes and manipulation of biological matters. A multiple input single output control system was designed and implemented to solve the issues of nanomanipulation of biological materials, feedback,...
Show moreWe developed the Atomic Force Microscopy (AFM) based nanorobot in combination with other nanomechanical sensors for the investigation of cell signaling pathways. The AFM nanorobotics hinge on the superior spatial resolution of AFM in imaging and extends it into the measurement of biological processes and manipulation of biological matters. A multiple input single output control system was designed and implemented to solve the issues of nanomanipulation of biological materials, feedback, response frequency and nonlinearity. The AFM nanorobotic system therefore provide the human-directed position, velocity and force control with high frequency feedback, and more importantly it can feed the operator with the real-time imaging of manipulation result from the fast-imaging based local scanning. The use of the system has taken the study of cellular process at the molecular scale into a new level.The cellular response to the physiological conditions can be significantly manifested in cellular mechanics. Dynamic mechanical property has been regarded as biomarkers, sometimes even regulators of the signaling and physiological processes, thus the name mechanobiology. We sought to characterize the relationship between the structural dynamics and the molecular dynamics and the role of them in the regulation of cell behavior. We used the AFM nanorobotics to investigate the mechanical properties in real-time of cells that are stimulated by different chemical species. These reagents could result in similar ion channel responses but distinctive mechanical behaviors. We applied these measurement results to establish a model that describes the cellular stimulation and the mechanical property change, a ``two-hit" model that comprises the loss of cell adhesion and the initiation of cell apoptosis. The first hit was verified by functional experiments: depletion of Calcium and nanosurgery to disrupt the cellular adhesion. The second hit was tested by a labeling of apoptotic markers that were revealed by flow cytometry. The model would then be able to decipher qualitatively the molecular dynamics infolded in the regulation of cell behavior.To decipher the signaling pathway quantitatively, we employed a nanomechanical sensor at the bottom of the cell, quartz crystal microbalance with energy dissipation monitoring (QCM-D) to monitor the change at the basal area of the cell. This would provide the real time focal adhesion information and would be used in accordance with the AFM measurement data on the top of the cell to build a more complete mechanical profile during the antibody induced signaling process. We developed a model from a systematic control perspective that considers the signaling cascade at certain stimulation as the controller and the mechanical and structural interaction of the cell as the plant. We firstly derived the plant model based on QCM-D and AFM measurement processes. A signaling pathway model was built on a grey box approach where part of the pathway map was delineated in detail while others were condensed into a single reaction. The model parameters were obtained by extracting the mechanical response from the experiment. The model refinements were conducted by testing a series of inhibition mechanisms and comparing the simulation data with the experimental data. The model was then used to predict the existences of certain reactions that are qualitatively reported in the literature.
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Title: Immunosensors using metallic nanoparticle-based signal enhancement for bacterial detection and tuberculosis diagnosis
Creator: Wang, Yun
Date: 2014
Collection: Electronic Theses & Dissertations
Description: Escherichia coli O157:H7 is one of the main foodborne/waterborne bacterial pathogens that can cause human illnesses with threat to public health. To control the spread of the contaminated food/water and minimize the harm to public health, rapid and sensitive detection methods need to be implemented. However, standard culture method requires two to four days to obtain results. The application of nanomaterials has drawn interest in the biosensor research to develop timely and...
Show moreEscherichia coli O157:H7 is one of the main foodborne/waterborne bacterial pathogens that can cause human illnesses with threat to public health. To control the spread of the contaminated food/water and minimize the harm to public health, rapid and sensitive detection methods need to be implemented. However, standard culture method requires two to four days to obtain results. The application of nanomaterials has drawn interest in the biosensor research to develop timely and low cost detection systems. Because of their unique characteristics, nanoparticles have been used to enhance biosensor sensitivity by increasing the target molecule capture efficiency or by amplifying detection signals. In this dissertation research, nanoparticle-based biosensors were designed for the rapid detection of E. coli O157:H7 in broth. Magnetic nanoparticles (MNPs) were conjugated with monoclonal antibodies to separate target E. coli O157:H7 cells from samples. Gold nanoparticles (AuNPs) conjugated with polyclonal antibodies were then introduced to the MNP-target complexes to form MNP-target-AuNP. By measuring the amount of gold nanoparticles through an electrochemical method, the presence and the amount of the target bacteria were determined. Based on this biosensor using AuNPs as labels for signal amplification, a tri-nano electrochemical immunosensor was developed by using three nanoparticles for the rapid detection. The gold nanoparticles (AuNPs) were conjugated with lead sulfide (PbS) nanoparticles as electrochemical reporters via oligonucleotide linkage. AuNPs were also functionalized with polyclonal anti-E. coli O157:H7 antibodies in order to bind the target bacterial cells which were captured and separated from the sample by antibody-functionalized MNPs. Because each AuNP was linked to multiple PbS nanoparticles, each binding event to the target resulted in substantial amplification. The signal of PbS was measured on screen-printed carbon electrode (SPCE) by square wave anodic stripping voltammetry (SWASV). Results showed that the biosensor could detect E. coli O157:H7 in the range of 101 to 106 colony forming units per milliliter (cfu/ml) with a signal-to-noise ratio ranging from 2.77 to 4.31. With sample preparation being minimized, results were obtained within 1 h from sample processing to final readout. Tuberculosis (TB) is considered as one of the most widely spread infectious diseases, with estimated 8.8 million new cases and 2 million deaths annually. The biosensor developed in this dissertation research was also applied for TB diagnosis. Gold nanoparticles with anti-IFN-gamma antibody were conjugated to oligonucleotides terminated with cadmium sulfide (CdS) nanoparticles. At the same time, AuNPs were conjugated with anti-IP-10 antibody and oligonucleotides terminated with PbS nanoparticles. Therefore, the electrochemical signals of cadmium and lead indicated IFN-gamma and IP-10, respectively. By introducing MNPs with antibodies to IFN-gamma or IP-10 and AuNP conjugates, IFN-gamma and IP-10 were detected separately in buffer and simultaneously in both buffer and plasma. The results showed that IFN-gamma in the range of 0.01 IU/ml to 10 IU/ml and IP-10 in the range of 0.01 ng/ml to 100 ng/ml were detected in 1 h. Due to its rapidity, high sensitivity and multiplex detection capability, this tri-nanobiosensor has potential applications in public health, biodefense, and food/water safety monitoring.
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Title: IMPROVING GAS BARRIER PROPERTIES OF SUGARCANE-BASED LLDPE WITH CELLULOSE NANOCRYSTALS
Creator: Natarajan, Madhumitha
Date: 2021
Collection: Electronic Theses & Dissertations
Description: This study was aimed at improving the gas barrier property of sugarcane-based LLDPE using cellulose nanocrystals (CNCs). Specifically, this study evaluated the effect of testing methods (isostatic versus gravimetric) on CO2 permeability coefficient (PCO2) and/or O2 permeability coefficient (PO2) of various bio-PE grades with different densities (LLDPE, LDPE, and HDPE) as well as the effect of CNC content on crystallinity, tortuosity factor, and gas barrier properties of bio-LLDPE sheets and...
Show moreThis study was aimed at improving the gas barrier property of sugarcane-based LLDPE using cellulose nanocrystals (CNCs). Specifically, this study evaluated the effect of testing methods (isostatic versus gravimetric) on CO2 permeability coefficient (PCO2) and/or O2 permeability coefficient (PO2) of various bio-PE grades with different densities (LLDPE, LDPE, and HDPE) as well as the effect of CNC content on crystallinity, tortuosity factor, and gas barrier properties of bio-LLDPE sheets and films. The isostatic and gravimetric methods yielded similar PCO2, irrespective of PE grade. However, the PCO2 negatively correlated with PE density. All nanocomposites showed considerable improvement in gas barrier irrespective of the CNC content. The PCO2 of LLDPE sheets decreased by 36% by adding 10 wt.% of CNCs into the sheet. Similarly, a significant decline in both PO2 (about 50%) and PCO2 (about 33%) of LLDPE films was obtained by adding 2.5 wt.% of CNCs into the films. Nevertheless, no correlation was established between gas permeability and percent crystallinity of LLDPE sheet since the PCO2 decreased almost linearly with increasing CNC content whereas the percent crystallinity of LLDPE increased only up to 2.5% CNC content and remained constant thereafter. In contrast, the tortuosity factors calculated from the diffusion coefficients increased almost linearly with CNC contents and correlated well with the gas permeability improvement in the bio-LLDPE-based nanocomposites. Consequently, the enhanced gas barrier in the nanocomposite was assigned to the tortuosity effect created by the impermeable cellulose nanocrystals rather than the changes in percent crystallinity.
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Title: Gas-phase synthesis of semiconductor nanocrystals and its applications
Creator: Rajib, Md, 1983-
Date: 2016
Collection: Electronic Theses & Dissertations
Description: Luminescent nanomaterials is a newly emerging field that provides challenges not only to fundamental research but also to innovative technology in several areas such as electronics, photonics, nanotechnology, display, lighting, biomedical engineering and environmental control. These nanomaterials come in various forms, shapes and comprises of semiconductors, metals, oxides, and inorganic and organic polymers. Most importantly, these luminescent nanomaterials can have different properties...
Show moreLuminescent nanomaterials is a newly emerging field that provides challenges not only to fundamental research but also to innovative technology in several areas such as electronics, photonics, nanotechnology, display, lighting, biomedical engineering and environmental control. These nanomaterials come in various forms, shapes and comprises of semiconductors, metals, oxides, and inorganic and organic polymers. Most importantly, these luminescent nanomaterials can have different properties owing to their size as compared to their bulk counterparts. Here we describe the use of plasmas in synthesis, modification, and deposition of semiconductor nanomaterials for luminescence applications.Nanocrystalline silicon is widely known as an efficient and tunable optical emitter and is attracting great interest for applications in several areas. To date, however, luminescent silicon nanocrystals (NCs) have been used exclusively in traditional rigid devices. For the field to advance towards new and versatile applications for nanocrystal-based devices, there is a need to investigate whether these NCs can be used in flexible and stretchable devices. We show how the optical and structural/morphological properties of plasma-synthesized silicon nanocrystals (Si NCs) change when they are deposited on stretchable substrates made of polydimethylsiloxane (PDMS). Synthesis of these NCs was performed in a nonthermal, low-pressure gas phase plasma reactor. To our knowledge, this is the first demonstration of direct deposition of NCs onto stretchable substrates.Additionally, in order to prevent oxidation and enhance the luminescence properties, a silicon nitride shell was grown around Si NCs. We have demonstrated surface nitridation of Si NCs in a single step process using non‒thermal plasma in several schemes including a novel dual-plasma synthesis/shell growth process. These coated NCs exhibit SiNx shells with composition depending on process parameters. While measurements including photoluminescence (PL), surface analysis, and defect identification indicate the shell is protective against oxidation compared to Si NCs without any shell growth.Gallium Nitride (GaN) is one of the most well-known semiconductor material and the industry standard for fabricating LEDs. The problem is that epitaxial growth of high-quality GaN requires costly substrates (e.g. sapphire), high temperatures, and long processing times. Synthesizing freestanding NCs of GaN, on the other hand, could enable these novel device morphologies, as the NCs could be incorporated into devices without the requirements imposed by epitaxial GaN growth. Synthesis of GaN NCs was performed using a fully gas-phase process. Different sizes of crystalline GaN nanoparticles were produced indicating versatility of this gas-phase process. Elemental analysis using X-ray photoelectron spectroscopy (XPS) indicated a possible nitrogen deficiency in the NCs; addition of secondary plasma for surface treatment indicates improving stoichiometric ratio and points towards a unique method for creating high-quality GaN NCs with ultimate alloying and doping for full-spectrum luminescence.
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Title: Fundamental electronic and structural properties of carbon onions in extreme environments
Creator: Al-Duhileb, Raied A.
Date: 2010
Collection: Electronic Theses & Dissertations

Title: Fabrication of nanostructures and nanostructure based interfaces for biosensor application
Creator: Srivastava, Devesh
Date: 2008
Collection: Electronic Theses & Dissertations

Title: Ex-vivo biomimetic interfaces for screening engineered nanomaterials
Creator: Liu, Ying, Ph. D.
Date: 2015
Collection: Electronic Theses & Dissertations
Description: AbstractEX-VIVO BIOMIMETIC INTERFACES For Screening engineered nanomaterialsByYing LiuEngineered nanomaterials (ENM) have attractive functional properties and are increasingly being used in commercial products. However, the potential health risks induced by ENM are poorly understood and difficult to evaluate. Since the first step in ENM toxicology pathway is to interface with cell membranes to trigger biological effects, improved methods are needed to measure ENM-biomembrane interactions....
Show moreAbstractEX-VIVO BIOMIMETIC INTERFACES For Screening engineered nanomaterialsByYing LiuEngineered nanomaterials (ENM) have attractive functional properties and are increasingly being used in commercial products. However, the potential health risks induced by ENM are poorly understood and difficult to evaluate. Since the first step in ENM toxicology pathway is to interface with cell membranes to trigger biological effects, improved methods are needed to measure ENM-biomembrane interactions. Therefore, the overall objective of my doctoral dissertation is to develop robust, high throughput nano-structured biosensors, to elucidate mechanisms of surface interaction between ENM and biomembrane, to evaluate ENM kinetics and performance, to predict ENM induced health risk, and to provide guideline for bio-safety design of nano-products with desired functions. The first generation of higher throughput interface was developed by accelerating the interface-assembly process and enhancing stability of a planar bilayer lipid membrane (pBLM). The diameter of a classical planar BLM is ~500 m. The novel planar BLM developed for this project was fabricated on nanopores (~700 nm) drilled through silicon nitride thin film using focused ion beam lithography. The resulting nano-biosensor enabled automatic BLM formation after integration into a microfluidic device with enhanced mechanical stability. Electrophysiology and electrochemical impedance spectroscopy was used to validate functionality of the nanopore pBLM. Then, transient current spikes induced by silica nanoparticles and integral conductance induced by carboxylate multi-wall carbon nanotubes, across giga-ohm nanopore pBLM, were measured. The chronoamperometric traces have single-pore sensitivity and temporal resolution on the order of millisecond. However, the first generation BLM requires manual formulation and expensive screening equipment, limiting its potential of commercialization.As a result, the second generation of high throughput biomimetic interface, tethered BLM on gold electrode was developed. Immobilization of BLM on surfaces offers advantages over pBLM, including enhanced stability and ion reservoir. Another advantage associated with tethered BLM is that it can be integrated onto complementary metal–oxide–semiconductor based microsystem with on-chip electrochemical detection. Using molecular self-assembly, the resulting microelectrode array based tethered BLM forms a continuous use and label-free detection platform that is suitable for microsystem implementation. The model interface, tethered BLM, verifies the viability of biocompatible fabrication technologies and is a milestone toward integrating electrochemical biosensor arrays and microelectronic instrumentation into high throughput, manual free and cost effective drug screening applications.Here, pore forming activities of functionalized silica nanoparticles, functionalized polystyrene nanoparticles (PNP) and functionalized polypropargyl glycolide nanoparticles (PGL) were characterized using high insulating tethered BLM. Electrical resistance trajectory was analyzed using empirical exponential model, providing dynamic information of ion leakage induced by various nanoparticles. Coupled with statistical hierarchical clustering post-analysis, the tethered BLM method could distinguish between nanoparticles based on size, charge and/or surface functional groups by monitoring dynamic electrical resistance and overall resistance loss. However, the exponential model failed to reproduce the resistance trend for –OH terminated PGL. As a result, a mechanistic kinetic model was developed to predict interaction kinetics of ENM with model BLM and to correlate effects of different component, and to assess biosensor performance. A 9 parameter model was designed using MATLAB and R, and then simplified into a 3 parameter model. The model developed helps elucidate molecular processes responsible for time-evolved electrochemical property/signal changes in tethered BLM following ENM exposure. Assuming second order reaction kinetics, the model uses two kinetic constants to describe the rates of ENM binding to, and lipid removal from, the interface. The rates were dependent on number of free nanoparticles, available site on the interface and mobile lipids fraction. The model was fit to membrane resistance, Rm vs. time data for interaction of a tethered BLM with two types of ENM: PGL and functionalized polystyrene nanoparticles. The model was able to predict diverse trends in the Rm vs. time data, including a continuous decrease (PNP) in Rm and an initial increase (PGL) in Rm followed by a decrease. The model also predicted that the biosensor is so sensitive that the interaction involving only 10-8% of bulk nanoparticles could generate measurable changes in the biosensor output. Then, kinetic constants for ENM extracted from time-evolved trends were analyzed using hierarchical clustering. The resulting dendrograms showed that ENM with different properties (composition, size, surface charge) could be statistically distinguished using this approach.
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