Matching Items (10)
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- All Subjects: Bioengineering
- All Subjects: Characterization
- Creators: Goryll, Michael
- Member of: ASU Electronic Theses and Dissertations
Description
The past two decades have been monumental in the advancement of microchips designed for a diverse range of medical applications and bio-analysis. Owing to the remarkable progress in micro-fabrication technology, complex chemical and electro-mechanical features can now be integrated into chip-scale devices for use in biosensing and physiological measurements. Some of these devices have made enormous contributions in the study of complex biochemical processes occurring at the molecular and cellular levels while others overcame the challenges of replicating various functions of human organs as implant systems. This thesis presents test data and analysis of two such systems. First, an ISFET based pH sensor is characterized for its performance in a continuous pH monitoring application. Many of the basic properties of ISFETs including I-V characteristics, pH sensitivity and more importantly, its long term drift behavior have been investigated. A new theory based on frequent switching of electric field across the gate oxide to decrease the rate of current drift has been successfully implemented with the help of an automated data acquisition and switching system. The system was further tested for a range of duty cycles in order to accurately determine the minimum length of time required to fully reset the drift. Second, a microfluidic based vestibular implant system was tested for its underlying characteristics as a light sensor. A computer controlled tilt platform was then implemented to further test its sensitivity to inclinations and thus it‟s more important role as a tilt sensor. The sensor operates through means of optoelectronics and relies on the signals generated from photodiode arrays as a result of light being incident on them. ISFET results show a significant drop in the overall drift and good linear characteristics. The drift was seen to reset at less than an hour. The photodiodes show ideal I-V comparison between photoconductive and photovoltaic modes of operation with maximum responsivity at 400nm and a shunt resistance of 394 MΩ. Additionally, post-processing of the tilt sensor to incorporate the sensing fluids is outlined. Based on several test and fabrication results, a possible method of sealing the open cavity of the chip using a UV curable epoxy has been discussed.
ContributorsMamun, Samiha (Author) / Christen, Jennifer Blain (Thesis advisor) / Goryll, Michael (Committee member) / Yu, Hongyu (Committee member) / Arizona State University (Publisher)
Created2011
Description
In-field characterization of photovoltaics is crucial to understanding performance and degradation mechanisms, subsequently improving overall reliability and lifespans. Current outdoor characterization is often limited by logistical difficulties, variable weather, and requirements to measure during peak production hours. It becomes a challenge to find a characterization technique that is affordable with a low impact on system performance while still providing useful device parameters. For added complexity, this characterization technique must have the ability to scale for implementation in large powerplant applications. This dissertation addresses some of the challenges of outdoor characterization by expanding the knowledge of a well-known indoor technique referred to as Suns-VOC. Suns-VOC provides a pseudo current-voltage curve that is free of any effects from series resistance. Device parameters can be extracted from this pseudo I-V curve, allowing for subsequent degradation analysis. This work introduces how to use Suns-VOC outdoors while normalizing results based on the different effects of environmental conditions. This technique is validated on single-cells, modules, and small arrays with accuracies capable of measuring yearly degradation. An adaptation to Suns-VOC, referred to as Suns-Voltage-Resistor (Suns-VR), is also introduced to complement the results from Suns-VOC. This work can potentially be used to provide a diagnostic tool for outdoor characterization in various applications, including residential, commercial, and industrial PV systems.
ContributorsKillam, Alexander Cameron (Author) / Bowden, Stuart G (Thesis advisor) / Goryll, Michael (Committee member) / Augusto, Andre (Committee member) / Rand, James (Committee member) / Arizona State University (Publisher)
Created2022
Description
Drug delivery has made a significant contribution to cancer immunotherapy and can have a tremendous impact on modulating immunometabolism, thereby affecting cancer outcomes. Notably, the science of delivery of cancer vaccines and immunotherapeutics, modulating immune cell functions has inspired development of several successful companies and clinical products. For example, cancer vaccines require activation of dendritic cells (DCs) and tumour associated Mɸs (TAMs) through modulation of their energy metabolism (e.g., glycolysis, glutaminolysis, Krebs cycle). Similar to activated immune cells, cancer cells also upregulate glucose and glutamine transporters for proliferation and survival. Cancer cells having accelerated energy metabolism, which has been exploited as a target for various therapeutic studies. In the first strategy, an immunometabolism strategy based on sustained release of succinate from biomaterials, which incorporate succinate in the backbone of the polymer was developed. This study demonstrates that succinate-based polymeric microparticles act as alarmins by modulating the immunometabolism of DCs and Mɸs to generate robust pro-inflammatory responses for melanoma treatment in immunocompetent young as well as aging mice. In the second strategy, a biomaterial-based strategy was developed to deliver metabolites one-step downstream of the node where the glycolytic pathway is inhibited, to specifically rescue DCs from glycolysis inhibition. The study successfully demonstrated for the first time that the glycolysis of DCs can be rescued both in vitro and in vivo using a biomaterial strategy of delivering metabolites downstream of the inhibitory node. Overall, it is believed that advanced drug delivery strategies will play an important role in marrying the fields of immunometabolism and immunotherapy to generate translatable anti-cancer treatments.
ContributorsInamdar, Sahil (Author) / Acharya, Abhinav P (Thesis advisor) / Rege, Kaushal (Committee member) / Green, Matthew (Committee member) / Curtis, Marion (Committee member) / Seetharam, Mahesh (Committee member) / Arizona State University (Publisher)
Created2022
Description
Sutures, staples, and tissue glues remain the primary means of tissue approximation and vessel ligation. Laser-activated tissue sealing is an alternative approach that conventionally employs light-absorbing chromophores and nanoparticles for converting near-infrared (NIR) laser to heat. The local increase in temperature engenders interdigitation of sealant and tissue biomolecules, resulting in rapid tissue sealing. Light-activated sealants (LASE) were developed in which indocyanine green (ICG) dye is embedded within a biopolymer matrix (silk or chitosan) for incisional defect repair. Light-activated tissue-integrating sutures (LATIS) that synergize the benefits of conventional suturing and laser sealing were also fabricated and demonstrated higher efficacies for tissue biomechanical recovery and repair in a full-thickness, dorsal surgical incision model in mice compared to commercial sutures and cyanoacrylate skin glue. Localized delivery of modulators of tissue repair, including histamine and copper, from LASE and LATIS further improved healed skin strength. In addition to incisional wounds, histamine co-delivered with silk fibroin LASE films accelerated the closure of full thickness, splinted excisional wounds in immunocompetent BALB/c mice and genetically obese and diabetic db/db mice, resulting in faster closure than Tegaderm wound dressing. Immunohistochemistry analyses showed LASE-histamine treatment enhanced wound repair involving mechanisms of neoangiogenesis, myofibroblast activation, transient epidermal EMT, and also improve healed skin biomechanical strength which are hallmarks of improved healing outcomes. Benefit of temporal delivery was further investigated of a second therapeutic (growth factor nanoparticles) in modulating wound healing outcomes in both acute and diabetic wounds. The hypothesis of temporal delivery of second therapeutic around the ‘transition period’ in wounds further improved wound closure kinetics and biomechanical recovery of skin strength. Laser sealing and approximation, together with delivery of immunomodulatory mediators, can lead to faster healing and tissue repair, thus reducing wound dehiscence, preventing wounds moving towards chronicity and lowering incidence of surgical site infections, all of which can have significant impact in the clinic.
ContributorsGhosh, Deepanjan (Author) / Rege, Kaushal (Thesis advisor) / Acharya, Abhinav (Committee member) / Holloway, Julianne (Committee member) / DiCaudo, David (Committee member) / P. Leung, Kai (Committee member) / Arizona State University (Publisher)
Created2021
Description
The use of mRNA for therapeutic purposes has gained significant attention due to its potential to treat a wide range of diseases, including cancer, infectious diseases, and genetic disorders. However, the efficient delivery of mRNA to target cells remains a major challenge, and delivery of mRNA faces major issues such as rapid degradation and poor cellular uptake. Aminoglycoside-derived lipopolymer nanoparticles (LPNs) have been shown as a promising platform for plasmid DNA (pDNA) delivery due to their stability, biocompatibility, and ability to encapsulate mRNA. The current study aims to develop and optimize LPNs formulation for the delivery of mRNA in aggressive cancer cells, using a combination of chemical synthesis, physicochemical characterization, and in vitro biological assays. From a small library of aminoglycoside-derived lipopolymers, the lead lipopolymers were screened for the efficient delivery of mRNA. The complexes were synthesized with different ratios of lipopolymers to mRNA. The appropriate binding ratios of lipopolymers and mRNA were determined by gel electrophoresis. The complexes were characterized using dynamic light scattering (DLS) and zeta potential. The transgene expression efficacy of polymers was evaluated using in vitro bioluminescence assay. The toxicity of LPNs and LPNs-mRNA complexes was evaluated using a 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay. The current study comprehensively investigates the optimization of the LPNs-mRNA formulation for enhanced efficacy in transgene expression in human advanced-stage melanoma cell lines.
ContributorsWubhayavedantapuram, Revanth (Author) / Rege, Kaushal (Thesis advisor) / Acharya, Abhinav (Committee member) / Yaron, Jordan (Committee member) / Arizona State University (Publisher)
Created2023
Description
This work describes efforts made toward the development of a compact, quantitative fluorescence-based multiplexed detection platform for point-of-care diagnostics. This includes the development of a microfluidic delivery and actuation system for multistep detection assays. Early detection of infectious diseases requires high sensitivity dependent on the precise actuation of fluids.
Methods of fluid actuation were explored to allow delayed delivery of fluidic reagents in multistep detection lateral flow assays (LFAs). Certain hydrophobic materials such as wax were successfully implemented in the LFA with the use of precision dispensed valves. Sublimating materials such as naphthalene were also characterized along with the implementation of a heating system for precision printing of the valves.
Various techniques of blood fractionation were also investigated and this work demonstrates successful blood fractionation in an LFA. The fluid flow of reagents was also characterized and validated with the use of mathematical models and multiphysics modeling software. Lastly intuitive, user-friendly mobile and desktop applications were developed to interface the underlying Arduino software. The work advances the development of a system which successfully integrates all components of fluid separation and delivery along with highly sensitive detection and a user-friendly interface; the system will ultimately provide clinically significant diagnostics in a of point-of-care device.
Methods of fluid actuation were explored to allow delayed delivery of fluidic reagents in multistep detection lateral flow assays (LFAs). Certain hydrophobic materials such as wax were successfully implemented in the LFA with the use of precision dispensed valves. Sublimating materials such as naphthalene were also characterized along with the implementation of a heating system for precision printing of the valves.
Various techniques of blood fractionation were also investigated and this work demonstrates successful blood fractionation in an LFA. The fluid flow of reagents was also characterized and validated with the use of mathematical models and multiphysics modeling software. Lastly intuitive, user-friendly mobile and desktop applications were developed to interface the underlying Arduino software. The work advances the development of a system which successfully integrates all components of fluid separation and delivery along with highly sensitive detection and a user-friendly interface; the system will ultimately provide clinically significant diagnostics in a of point-of-care device.
ContributorsArafa, Hany M (Author) / Blain Christen, Jennifer M (Thesis advisor) / Goryll, Michael (Committee member) / Smith, Barbara (Committee member) / Arizona State University (Publisher)
Created2018
Description
Silicon carbide (SiC) has always been considered as an excellent material for high temperature and high power devices. Since SiC is the only compound semiconductor whose native oxide is silicon dioxide (SiO2), it puts SiC in a unique position. Although SiC metal oxide semiconductor (MOS) technology has made significant progress in recent years, there are still a number of issues to be overcome before more commercial SiC devices can enter the market. The prevailing issues surrounding SiC MOSFET devices are the low channel mobility, the low quality of the oxide layer and the high interface state density at the SiC/SiO2 interface. Consequently, there is a need for research to be performed in order to have a better understanding of the factors causing the poor SiC/SiO2 interface properties. In this work, we investigated the generation lifetime in SiC materials by using the pulsed metal oxide semiconductor (MOS) capacitor method and measured the interface state density distribution at the SiC/SiO2 interface by using the conductance measurement and the high-low frequency capacitance technique. These measurement techniques have been performed on n-type and p-type SiC MOS capacitors. In the course of our investigation, we observed fast interface states at semiconductor-dielectric interfaces in SiC MOS capacitors that underwent three different interface passivation processes, such states were detected in the nitrided samples but not observed in PSG-passivated samples. This result indicate that the lack of fast states at PSG-passivated interface is one of the main reasons for higher channel mobility in PSG MOSFETs. In addition, the effect of mobile ions in the oxide on the response time of interface states has been investigated. In the last chapter we propose additional methods of investigation that can help elucidate the origin of the particular interface states, enabling a more complete understanding of the SiC/SiO2 material system.
ContributorsKao, Wei-Chieh (Author) / Goryll, Michael (Thesis advisor) / Chowdhury, Srabanti (Committee member) / Yu, Hongbin (Committee member) / Marinella, Matthew (Committee member) / Arizona State University (Publisher)
Created2015
Description
A single cell is the very fundamental element in an organism; however, it contains the most complicated and stochastic information, such as DNA, RNA, and protein expression. Thus, it is a necessity to study stochastic gene expression in order to discover the biosignatures at the single-cell level. The heterogeneous gene expression of single cells from an isogenic cell population has already been studied for years. Yet to date, single-cell studies have been confined in a fashion of analyzing isolated single cells or a dilution of cells from the bulk-cell populations. These techniques or devices are limited by either the mechanism of cell lysis or the difficulties to target specific cells without harming neighboring cells.
This dissertation presents the development of a laser lysis chip combined with a two-photon laser system to perform single-cell lysis of single cells in situ from three-dimensional (3D) cell spheroids followed by analysis of the cell lysate with two-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The 3D spheroids were trapped in a well in the custom-designed laser lysis chip. Next, each single cell of interest in the 3D spheroid was identified and lysed one at a time utilizing a two-photon excited laser. After each cell lysis, the contents inside the target cell were released to the surrounding media and carried out to the lysate collector. Finally, the gene expression of each individual cell was measured by two-step RT-qPCR then spatially mapped back to its original location in the spheroids to construct a 3D gene expression map.
This novel technology and approach enables multiple gene expression measurements in single cells of multicellular organisms as well as cell-to-cell heterogeneous responses to the environment with spatial recognition. Furthermore, this method can be applied to study precancerous tissues for a better understanding of cancer progression and for identifying early tumor development.
This dissertation presents the development of a laser lysis chip combined with a two-photon laser system to perform single-cell lysis of single cells in situ from three-dimensional (3D) cell spheroids followed by analysis of the cell lysate with two-step reverse transcription-quantitative polymerase chain reaction (RT-qPCR). The 3D spheroids were trapped in a well in the custom-designed laser lysis chip. Next, each single cell of interest in the 3D spheroid was identified and lysed one at a time utilizing a two-photon excited laser. After each cell lysis, the contents inside the target cell were released to the surrounding media and carried out to the lysate collector. Finally, the gene expression of each individual cell was measured by two-step RT-qPCR then spatially mapped back to its original location in the spheroids to construct a 3D gene expression map.
This novel technology and approach enables multiple gene expression measurements in single cells of multicellular organisms as well as cell-to-cell heterogeneous responses to the environment with spatial recognition. Furthermore, this method can be applied to study precancerous tissues for a better understanding of cancer progression and for identifying early tumor development.
ContributorsWang, Guozhen (Author) / Meldrum, Deirdre R (Thesis advisor) / Chao, Shih-hui (Committee member) / Wang, Hong (Committee member) / Goryll, Michael (Committee member) / Arizona State University (Publisher)
Created2016
Description
InAs/InAsSb type-II superlattices (T2SLs) can be considered as potential alternatives for conventional HgCdTe photodetectors due to improved uniformity, lower manufacturing costs with larger substrates, and possibly better device performance. This dissertation presents a comprehensive study on the structural, optical and electrical properties of InAs/InAsSb T2SLs grown by Molecular Beam Epitaxy.
The effects of different growth conditions on the structural quality were thoroughly investigated. Lattice-matched condition was successfully achieved and material of exceptional quality was demonstrated.
After growth optimization had been achieved, structural defects could hardly be detected, so different characterization techniques, including etch-pit-density (EPD) measurements, cathodoluminescence (CL) imaging and X-ray topography (XRT), were explored, in attempting to gain better knowledge of the sparsely distributed defects. EPD revealed the distribution of dislocation-associated pits across the wafer. Unfortunately, the lack of contrast in images obtained by CL imaging and XRT indicated their inability to provide any quantitative information about defect density in these InAs/InAsSb T2SLs.
The nBn photodetectors based on mid-wave infrared (MWIR) and long-wave infrared (LWIR) InAs/InAsSb T2SLs were fabricated. The significant difference in Ga composition in the barrier layer coupled with different dark current behavior, suggested the possibility of different types of band alignment between the barrier layers and the absorbers. A positive charge density of 1.8 × 1017/cm3 in the barrier of MWIR nBn photodetector, as determined by electron holography, confirmed the presence of a potential well in its valence band, thus identifying type-II alignment. In contrast, the LWIR nBn photodetector was shown to have type-I alignment because no sign of positive charge was detected in its barrier.
Capacitance-voltage measurements were performed to investigate the temperature dependence of carrier densities in a metal-oxide-semiconductor (MOS) structure based on MWIR InAs/InAsSb T2SLs, and a nBn structure based on LWIR InAs/InAsSb T2SLs. No carrier freeze-out was observed in either sample, indicating very shallow donor levels. The decrease in carrier density when temperature increased was attributed to the increased density of holes that had been thermally excited from localized states near the oxide/semiconductor interface in the MOS sample. No deep-level traps were revealed in deep-level transient spectroscopy temperature scans.
The effects of different growth conditions on the structural quality were thoroughly investigated. Lattice-matched condition was successfully achieved and material of exceptional quality was demonstrated.
After growth optimization had been achieved, structural defects could hardly be detected, so different characterization techniques, including etch-pit-density (EPD) measurements, cathodoluminescence (CL) imaging and X-ray topography (XRT), were explored, in attempting to gain better knowledge of the sparsely distributed defects. EPD revealed the distribution of dislocation-associated pits across the wafer. Unfortunately, the lack of contrast in images obtained by CL imaging and XRT indicated their inability to provide any quantitative information about defect density in these InAs/InAsSb T2SLs.
The nBn photodetectors based on mid-wave infrared (MWIR) and long-wave infrared (LWIR) InAs/InAsSb T2SLs were fabricated. The significant difference in Ga composition in the barrier layer coupled with different dark current behavior, suggested the possibility of different types of band alignment between the barrier layers and the absorbers. A positive charge density of 1.8 × 1017/cm3 in the barrier of MWIR nBn photodetector, as determined by electron holography, confirmed the presence of a potential well in its valence band, thus identifying type-II alignment. In contrast, the LWIR nBn photodetector was shown to have type-I alignment because no sign of positive charge was detected in its barrier.
Capacitance-voltage measurements were performed to investigate the temperature dependence of carrier densities in a metal-oxide-semiconductor (MOS) structure based on MWIR InAs/InAsSb T2SLs, and a nBn structure based on LWIR InAs/InAsSb T2SLs. No carrier freeze-out was observed in either sample, indicating very shallow donor levels. The decrease in carrier density when temperature increased was attributed to the increased density of holes that had been thermally excited from localized states near the oxide/semiconductor interface in the MOS sample. No deep-level traps were revealed in deep-level transient spectroscopy temperature scans.
ContributorsShen, Xiaomeng (Author) / Zhang, Yong-Hang (Thesis advisor) / Smith, David J. (Thesis advisor) / Alford, Terry (Committee member) / Goryll, Michael (Committee member) / Mccartney, Martha R (Committee member) / Arizona State University (Publisher)
Created2015
Description
Early detection and treatment of disease is paramount for improving human health and wellness. Micro-scale devices promote new opportunities for the rapid, cost-effective, and accurate identification of altered biological states indicative of disease early-onset; these devices function at a scale more sensitive to numerous biological processes. The application of Micro-Electro-Mechanical Systems (MEMS) in biomedical settings has recently emerged and flourished over course of the last two decades, requiring a deep understanding of material biocompatibility, biosensing sensitively/selectively, biological constraints for artificial tissue/organ replacement, and the regulations in place to ensure device safety. Capitalizing on the inherent physical differences between cancerous and healthy cells, our ultra-thin silicone membrane enables earlier identification of bladder cancer—with a 70% recurrence rate. Building on this breakthrough, we have devised an array to multiplex this sample-analysis in real-time as well as expanding beyond bladder cancer. The introduction of new materials—with novel properties—to augment current and create innovative medical implants requires the careful analysis of material impact on cellular toxicity, mutagenicity, reactivity, and stability. Finally, the achievement of replacing defective biological systems with implanted artificial equivalents that must function within the same biological constraints, have consistent reliability, and ultimately show the promise of improving human health as demonstrated by our hydrogel check valve. The ongoing proliferation, expanding prevalence, and persistent improvement in MEMS devices through greater sensitivity, specificity, and integration with biological processes will undoubtedly bolster medical science with novel MEMS-based diagnostics and therapeutics.
ContributorsPodlevsky, Jennie Hewitt Appel (Author) / Chae, Junseok (Thesis advisor) / Goryll, Michael (Committee member) / Kozicki, Michael (Committee member) / Nikkhah, Mehdi (Committee member) / Arizona State University (Publisher)
Created2018