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Description
Dielectrophoresis (DEP) is a technique that influences the motion of polarizable particles in an electric field gradient. DEP can be combined with other effects that influence the motion of a particle in a microchannel, such as electrophoresis and electroosmosis. Together, these three can be used to probe properties of an analyte, including charge, conductivity, and zeta potential. DEP shows promise as a high-resolution differentiation and separation method, with the ability to distinguish between subtly-different populations. This, combined with the fast (on the order of minutes) analysis times offered by the technique, lend it many of the features necessary to be used in rapid diagnostics and point-of-care devices.
Here, a mathematical model of dielectrophoretic data is presented to connect analyte properties with data features, including the intercept and slope, enabling DEP to be used in applications which require this information. The promise of DEP to distinguish between analytes with small differences is illustrated with antibiotic resistant bacteria. The DEP system is shown to differentiate between methicillin-resistant and susceptible Staphylococcus aureus. This differentiation was achieved both label free and with bacteria that had been fluorescently-labeled. Klebsiella pneumoniae carbapenemase-positive and negative Klebsiella pneumoniae were also distinguished, demonstrating the differentiation for a different mechanism of antibiotic resistance. Differences in dielectrophoretic behavior as displayed by S. aureus and K. pneumoniae were also shown by Staphylococcus epidermidis. These differences were exploited for a separation in space of gentamicin-resistant and -susceptible S. epidermidis. Besides establishing the ability of DEP to distinguish between populations with small biophysical differences, these studies illustrate the possibility for the use of DEP in applications such as rapid diagnostics.
Here, a mathematical model of dielectrophoretic data is presented to connect analyte properties with data features, including the intercept and slope, enabling DEP to be used in applications which require this information. The promise of DEP to distinguish between analytes with small differences is illustrated with antibiotic resistant bacteria. The DEP system is shown to differentiate between methicillin-resistant and susceptible Staphylococcus aureus. This differentiation was achieved both label free and with bacteria that had been fluorescently-labeled. Klebsiella pneumoniae carbapenemase-positive and negative Klebsiella pneumoniae were also distinguished, demonstrating the differentiation for a different mechanism of antibiotic resistance. Differences in dielectrophoretic behavior as displayed by S. aureus and K. pneumoniae were also shown by Staphylococcus epidermidis. These differences were exploited for a separation in space of gentamicin-resistant and -susceptible S. epidermidis. Besides establishing the ability of DEP to distinguish between populations with small biophysical differences, these studies illustrate the possibility for the use of DEP in applications such as rapid diagnostics.
ContributorsHilton, Shannon (Author) / Hayes, Mark A. (Thesis advisor) / Borges, Chad (Committee member) / Herckes, Pierre (Committee member) / Arizona State University (Publisher)
Created2019
Description
Antibodies are naturally occurring proteins that protect a host during infection through direct neutralization and/or recruitment of the innate immune system. Unfortunately, in some infections, antibodies present unique hurdles that must be overcome for a safer and more efficacious antibody-based therapeutic (e.g., antibody dependent viral enhancement (ADE) and inflammatory pathology). This dissertation describes the utilization of plant expression systems to produce N-glycan specific antibody-based therapeutics for Dengue Virus (DENV) and Chikungunya Virus (CHIKV). The Fc region of an antibody interacts with Fcγ Receptors (FcγRs) on immune cells and components of the innate immune system. Each class of immune cells has a distinct action of neutralization (e.g., antibody dependent cell-mediated cytotoxicity (ADCC) and antibody dependent cell-mediated phagocytosis (ADCP)). Therefore, structural alteration of the Fc region results in novel immune pathways of protection. One approach is to modulate the N-glycosylation in the Fc region of the antibody. Of scientific significance, is the plant’s capacity to express human antibodies with homogenous plant and humanized N-glycosylation (WT and GnGn, respectively). This allows to study how specific glycovariants interact with other components of the immune system to clear an infection, producing a tailor-made antibody for distinct diseases. In the first section, plant-produced glycovariants were explored for reduced interactions with specific FcγRs for the overall reduction in ADE for DENV infections. The results demonstrate a reduction in ADE of our plant-produced monoclonal antibodies in in vitro experiments, which led to a greater survival in vivo of immunodeficient mice challenged with lethal doses of DENV and a sub-lethal dose of DENV in ADE conditions. In the second section, plant-produced glycovariants were explored for increased interaction with specific FcγRs to improve ADCC in the treatment of the highly inflammatory CHIKV. The results demonstrate an increase ADCC activity in in vitro experiments and a reduction in CHIKV-associated inflammation in in vivo mouse models. Overall, the significance of this dissertation is that it can provide a treatment for DENV and CHIKV; but equally importantly, give insight to the role of N-glycosylation in antibody effector functions, which has a broader implication for therapeutic development for other viral infections.
ContributorsHurtado, Jonathan (Author) / Chen, Qiang (Thesis advisor) / Arntzen, Charles (Committee member) / Borges, Chad (Committee member) / Lake, Douglas (Committee member) / Arizona State University (Publisher)
Created2019
Description
DNA, RNA and Protein are three pivotal biomolecules in human and other organisms, playing decisive roles in functionality, appearance, diseases development and other physiological phenomena. Hence, sequencing of these biomolecules acquires the prime interest in the scientific community. Single molecular identification of their building blocks can be done by a technique called Recognition Tunneling (RT) based on Scanning Tunneling Microscope (STM). A single layer of specially designed recognition molecule is attached to the STM electrodes, which trap the targeted molecules (DNA nucleoside monophosphates, RNA nucleoside monophosphates or amino acids) inside the STM nanogap. Depending on their different binding interactions with the recognition molecules, the analyte molecules generate stochastic signal trains accommodating their “electronic fingerprints”. Signal features are used to detect the molecules using a machine learning algorithm and different molecules can be identified with significantly high accuracy. This, in turn, paves the way for rapid, economical nanopore sequencing platform, overcoming the drawbacks of Next Generation Sequencing (NGS) techniques.
To read DNA nucleotides with high accuracy in an STM tunnel junction a series of nitrogen-based heterocycles were designed and examined to check their capabilities to interact with naturally occurring DNA nucleotides by hydrogen bonding in the tunnel junction. These recognition molecules are Benzimidazole, Imidazole, Triazole and Pyrrole. Benzimidazole proved to be best among them showing DNA nucleotide classification accuracy close to 99%. Also, Imidazole reader can read an abasic monophosphate (AP), a product from depurination or depyrimidination that occurs 10,000 times per human cell per day.
In another study, I have investigated a new universal reader, 1-(2-mercaptoethyl)pyrene (Pyrene reader) based on stacking interactions, which should be more specific to the canonical DNA nucleosides. In addition, Pyrene reader showed higher DNA base-calling accuracy compare to Imidazole reader, the workhorse in our previous projects. In my other projects, various amino acids and RNA nucleoside monophosphates were also classified with significantly high accuracy using RT. Twenty naturally occurring amino acids and various RNA nucleosides (four canonical and two modified) were successfully identified. Thus, we envision nanopore sequencing biomolecules using Recognition Tunneling (RT) that should provide comprehensive betterment over current technologies in terms of time, chemical and instrumental cost and capability of de novo sequencing.
To read DNA nucleotides with high accuracy in an STM tunnel junction a series of nitrogen-based heterocycles were designed and examined to check their capabilities to interact with naturally occurring DNA nucleotides by hydrogen bonding in the tunnel junction. These recognition molecules are Benzimidazole, Imidazole, Triazole and Pyrrole. Benzimidazole proved to be best among them showing DNA nucleotide classification accuracy close to 99%. Also, Imidazole reader can read an abasic monophosphate (AP), a product from depurination or depyrimidination that occurs 10,000 times per human cell per day.
In another study, I have investigated a new universal reader, 1-(2-mercaptoethyl)pyrene (Pyrene reader) based on stacking interactions, which should be more specific to the canonical DNA nucleosides. In addition, Pyrene reader showed higher DNA base-calling accuracy compare to Imidazole reader, the workhorse in our previous projects. In my other projects, various amino acids and RNA nucleoside monophosphates were also classified with significantly high accuracy using RT. Twenty naturally occurring amino acids and various RNA nucleosides (four canonical and two modified) were successfully identified. Thus, we envision nanopore sequencing biomolecules using Recognition Tunneling (RT) that should provide comprehensive betterment over current technologies in terms of time, chemical and instrumental cost and capability of de novo sequencing.
ContributorsSen, Suman (Author) / Lindsay, Stuart (Thesis advisor) / Zhang, Peiming (Thesis advisor) / Gould, Ian R. (Committee member) / Borges, Chad (Committee member) / Arizona State University (Publisher)
Created2016
Description
Efficient separation techniques for organelles and bacteria in the micron- and sub-micron range are required for various analytical challenges. Mitochondria have a wide size range resulting from the sub-populations, some of which may be associated with diseases or aging. However, traditional methods can often not resolve within-species size variations. Strategies to separate mitochondrial sub-populations by size are thus needed to study the importance of this organelle in cellular functions. Additionally, challenges also exist in distinguishing the sub-populations of bio-species which differ in the surface charge while possessing similar size, such as Salmonella typhimurium (Salmonella). The surface charge of Salmonella wild-type is altered upon environmental stimulations, influencing the bacterial survival and virulence within the host tissue. Therefore, it is important to explore methods to identify the sub-populations of Salmonella.
This work exploits insulator-based dielectrophoresis (iDEP) for the manipulation of mitochondria and Salmonella. The iDEP migration and trapping of mitochondria were investigated under both DC and low-frequency AC conditions, establishing that mitochondria exhibit negative DEP. Also, the first realization of size-based iDEP sorting experiments of mitochondria were demonstrated. As for Salmonella, the preliminary study revealed positive DEP behavior. Distinct trapping potential thresholds were found for the sub-populations with different surface charges.
Further, DEP was integrated with a non-intuitive migration mechanism termed absolute negative mobility (ANM), inducing a deterministic trapping component which allows the directed transport of µm- and sub-µm sized (bio)particles in microfluidic devices with a nonlinear post array under the periodic action of electrokinetic and dielectrophoretic forces. Regimes were revealed both numerically and experimentally in which larger particles migrate against the average applied force, whereas smaller particles show normal response. Moreover, this deterministic ANM (dANM) was characterized with polystyrene beads demonstrating improved migration speed at least two orders of magnitude higher compared to previous ANM systems with similar sized colloids. In addition, dANM was induced for mitochondria with an AC-overlaid waveform representing the first demonstration of ANM migration with biological species. Thus, it is envisioned that the efficient size selectivity of this novel migration mechanism can be employed in nanotechnology, organelle sub-population studies or fractionating protein nanocrystals.
This work exploits insulator-based dielectrophoresis (iDEP) for the manipulation of mitochondria and Salmonella. The iDEP migration and trapping of mitochondria were investigated under both DC and low-frequency AC conditions, establishing that mitochondria exhibit negative DEP. Also, the first realization of size-based iDEP sorting experiments of mitochondria were demonstrated. As for Salmonella, the preliminary study revealed positive DEP behavior. Distinct trapping potential thresholds were found for the sub-populations with different surface charges.
Further, DEP was integrated with a non-intuitive migration mechanism termed absolute negative mobility (ANM), inducing a deterministic trapping component which allows the directed transport of µm- and sub-µm sized (bio)particles in microfluidic devices with a nonlinear post array under the periodic action of electrokinetic and dielectrophoretic forces. Regimes were revealed both numerically and experimentally in which larger particles migrate against the average applied force, whereas smaller particles show normal response. Moreover, this deterministic ANM (dANM) was characterized with polystyrene beads demonstrating improved migration speed at least two orders of magnitude higher compared to previous ANM systems with similar sized colloids. In addition, dANM was induced for mitochondria with an AC-overlaid waveform representing the first demonstration of ANM migration with biological species. Thus, it is envisioned that the efficient size selectivity of this novel migration mechanism can be employed in nanotechnology, organelle sub-population studies or fractionating protein nanocrystals.
ContributorsLuo, Jinghui (Author) / Ros, Alexandra (Thesis advisor) / Hayes, Mark (Committee member) / Borges, Chad (Committee member) / Arizona State University (Publisher)
Created2015
Description
Quiescin sulfhydryl oxidase 1 (QSOX1) is a highly conserved disulfide bond-generating enzyme that represents the ancient fusion of two major thiol-disulfide oxidoreductase gene families: thioredoxin and ERV. QSOX1 was first linked with cancer after being identified as overexpressed in pancreatic ductal adenocarcinoma (but not in adjacent normal ductal epithelia, infiltrating lymphocytes, or chronic pancreatitis). QSOX1 overexpression has been confirmed in a number of other histological tumor types, such as breast, lung, kidney, prostate, and others. Expression of QSOX1 supports a proliferative and invasive phenotype in tumor cells, and its enzymatic activity is critical for promoting an invasive phenotype. An in vivo tumor growth study utilizing the pancreatic tumor cell line MIAPaCa-2 containing a QSOX1-silencing shRNA construct revealed that QSOX1 expression supports a proliferative phenotype. These preliminary studies suggest that suppressing the enzymatic activity of QSOX1 could represent a novel therapeutic strategy to inhibit proliferation and invasion of malignant neoplasms.
The goal of this research was to identify and characterize biologically active small molecule inhibitors for QSOX1. Chemical inhibition of QSOX1 enzymatic activity was hypothesized to reduce growth and invasion of tumor cells. Recombinant QSOX1 was screened against libraries of small molecules using an enzymatic activity assay to identify potential QSOX1 inhibitors. Two lead QSOX1 inhibitors were confirmed, 2-phenyl-1, 2-benzisoselenazol-3-one (ebselen), and 3-methoxy-n-[4-(1 pyrrolidinyl)phenyl]benzamide. The biological activity of these compounds is consistent with QSOX1 knockdown in tumor cell lines, reducing growth and invasion in vitro. Treatment of tumor cells with these compounds also resulted in specific ECM defects, a phenotype associated with QSOX1 knockdown. Additionally, these compounds were shown to be active in pancreatic and renal cancer xenografts, reducing tumor growth with daily treatment. For ebselen, the molecular mechanism of inhibition was determined using a combination of biochemical and mass spectrometric techniques. The results obtained in these studies provide proof-of-principle that targeting QSOX1 enzymatic activity with chemical compounds represents a novel potential therapeutic avenue worthy of further investigation in cancer. Additionally, the utility of these small molecules as chemical probes will yield future insight into the general biology of QSOX1, including the identification of novel substrates of QSOX1.
The goal of this research was to identify and characterize biologically active small molecule inhibitors for QSOX1. Chemical inhibition of QSOX1 enzymatic activity was hypothesized to reduce growth and invasion of tumor cells. Recombinant QSOX1 was screened against libraries of small molecules using an enzymatic activity assay to identify potential QSOX1 inhibitors. Two lead QSOX1 inhibitors were confirmed, 2-phenyl-1, 2-benzisoselenazol-3-one (ebselen), and 3-methoxy-n-[4-(1 pyrrolidinyl)phenyl]benzamide. The biological activity of these compounds is consistent with QSOX1 knockdown in tumor cell lines, reducing growth and invasion in vitro. Treatment of tumor cells with these compounds also resulted in specific ECM defects, a phenotype associated with QSOX1 knockdown. Additionally, these compounds were shown to be active in pancreatic and renal cancer xenografts, reducing tumor growth with daily treatment. For ebselen, the molecular mechanism of inhibition was determined using a combination of biochemical and mass spectrometric techniques. The results obtained in these studies provide proof-of-principle that targeting QSOX1 enzymatic activity with chemical compounds represents a novel potential therapeutic avenue worthy of further investigation in cancer. Additionally, the utility of these small molecules as chemical probes will yield future insight into the general biology of QSOX1, including the identification of novel substrates of QSOX1.
ContributorsHanavan, Paul D (Author) / Lake, Douglas (Thesis advisor) / LaBaer, Joshua (Committee member) / Mangone, Marco (Committee member) / Borges, Chad (Committee member) / Arizona State University (Publisher)
Created2015
Description
For reading DNA bases more accurately, a series of nitrogen-containing aromatic heterocycles have been designed and synthesized as candidates of universal reader to interact with all naturally occurring DNA nucleobases by hydrogen bonding interaction and eventually is used to read DNA by recognition tunneling. These recognition molecules include 6-mercapto-1H-benzo[d]imidazole-2-carboxamide, 5-(2-mercaptoethyl)-1H-imidazole-2-carboxamide, 5-(2-mercaptoethyl)-4H-1,2,4-traizole-3-carboxamide and 1-(2-mercaptoethyl)-1H-pyrrole-3-carboxamide. Their formation of hydrogen bonding complexes with nucleobases was studied and association constants were measured by proton NMR titration experiments in deuterated chloroform at room temperature. To do so, the mercaptoethyl chain or thiol group of these reading molecules was replaced or protected with the more lipophilic group to increase the solubility of these candidates in CDCl3. The 3' and 5' hydroxyl groups of deoxyadenosine (dA), deoxyguanosine (dG), deoxycytidine (dC) and thymidine (dT) were protected with tert-butyldimethylsilyl (TBDMS) to eliminate hydrogen bonding competition from the hydroxyl protons with these candidates as well as to increase the solubility of the nucleosides in CDCl3 for NMR titration experiment. Benzimidazole and imidazole containing readers exhibited the strongest H-bonding affinity towards DNA bases where pyrrole containing reader showed the weakest affinity. In all cases, dG revealed the strongest affinity towards the readers while dA showed the least.
The molecular complex formation in aqueous solution was studied by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry. The formation of both 1:1 and 2:1 complexes between one or two reading molecules and a DNA nucleotide were observed by ESI mass. A series of amino acids and carbohydrates were also examined by mass spectrometry to show the formation of non-covalent complexes with imidazole reader in aqueous solution. The experimental results were compared by calculating energies of ground state conformers of individual molecules and their complexes using computer modeling study by DFT calculations. These studies give insights into the molecular interactions that happen in a nanogap during recognition tunneling experiments.
The molecular complex formation in aqueous solution was studied by electrospray ionization mass spectrometry (ESI-MS) and tandem mass spectrometry. The formation of both 1:1 and 2:1 complexes between one or two reading molecules and a DNA nucleotide were observed by ESI mass. A series of amino acids and carbohydrates were also examined by mass spectrometry to show the formation of non-covalent complexes with imidazole reader in aqueous solution. The experimental results were compared by calculating energies of ground state conformers of individual molecules and their complexes using computer modeling study by DFT calculations. These studies give insights into the molecular interactions that happen in a nanogap during recognition tunneling experiments.
ContributorsBiswas, Sovan (Author) / Lindsay, Stuart (Thesis advisor) / Zhang, Peiming (Thesis advisor) / Borges, Chad (Committee member) / Gould, Ian (Committee member) / Arizona State University (Publisher)
Created2016
Description
In this thesis, a breadboard Integrated Microarray Printing and Detection System (IMPDS) was proposed to address key limitations of traditional microarrays. IMPDS integrated two core components of a high-resolution surface plasmon resonance imaging (SPRi) system and a piezoelectric dispensing system that can print ultra-low volume droplets. To avoid evaporation of droplets in the microarray, a 100 μm thick oil layer (dodecane) was used to cover the chip surface. The interaction between BSA (Bovine serum albumin) and Anti-BSA was used to evaluate the capability of IMPDS. The alignment variability of printing, stability of droplets array and quantification of protein-protein interactions based on nanodroplet array were evaluated through a 10 x 10 microarray on SPR sensor chip. Binding kinetic constants obtained from IMPDS are close with results from commercial SPR setup (BI-3000), which indicates that IMPDS is capable to measure kinetic constants accurately. The IMPDS setup has following advantages: 1) nanoliter scale sample consumption, 2) high-throughput detection with real-time kinetic information for biomolecular interactions, 3) real-time information during printing and spot-on-spot detection of biomolecular interactions 4) flexible selection of probes and receptors (M x N interactions). Since IMPDS studies biomolecular interactions with low cost and high flexibility in real-time manner, it has great potential in applications such as drug discovery, food safety and disease diagnostics, etc.
ContributorsXiao, Feng (Author) / Tao, Nongjian (Thesis advisor) / Borges, Chad (Committee member) / Guo, Jia (Committee member) / Arizona State University (Publisher)
Created2017
Description
Cancer is a heterogeneous disease with discrete oncogenic mechanisms. P53 mutation is the most common oncogenic mutation in many cancers including breast cancer. This dissertation focuses on fundamental genetic alterations enforced by p53 mutation as an indirect target. p53 mutation upregulates the mevalonate pathway genes altering cholesterol biosynthesis and prenylation. Prenylation, a lipid modification, is required for small GTPases signaling cascades. Project 1 demonstrates that prenylation inhibition can specifically target cells harboring p53 mutation resulting in reduced tumor proliferation and migration. Mutating p53 is associated with Ras and RhoA activation and statin prevents this activity by inhibiting prenylation. Ras-related pathway genes were selected from the transcriptomic analysis for evaluating correlation to statin sensitivity. A gene signature of seventeen genes and TP53 genotype (referred to as MPR signature) is generated to predict response to statins. MPR signature is validated through two datasets of drug screening in cell lines. As advancements in targeted gene modification are rising, the CRISPR-Cas9 technology has emerged as a new cancer therapeutic strategy. One of the important risk factors in gene therapy is the immune recognition of the exogenous therapeutic tool, resulting in obstruction of treatment and possibly serious health consequences. Project 2 describes a method development that can potentially improve the safety and efficacy of gene-targeting proteins. A cohort of 155 healthy individuals was screened for pre-existing B cell and T cell immune response to the S. pyogenes Cas9 protein. We detected antibodies against Cas9 in more than 10% of the healthy population and identified two immunodominant T cell epitopes of this protein. A de-immunized Cas9 that maintains the wild-type functionality was engineered by mutating the identified T cell epitopes. The gene signature and method described here have the potential to improve strategies for genome-driven tumor targeting.
ContributorsRoshdi Ferdosi, Shayesteh (Author) / Anderson, Karen S (Thesis advisor) / LaBaer, Joshua (Thesis advisor) / Woodbury, Neel (Committee member) / Borges, Chad (Committee member) / Arizona State University (Publisher)
Created2017
Description
Quiescin Sulfhydryl Oxidase 1 (QSOX1) generates disulfide bonds in its client substrates via oxidation of free thiols. Localized to the Golgi and secreted, QSOX1 helps to fold proteins into their active form. Early work with QSOX1 in cancer began with the identification of a peptide from the long form of QSOX1 in plasma from patients with pancreatic ductal adenocarcinoma. Subsequent work confirmed the overexpression of QSOX1 in numerous cancers in addition to pancreatic, including those originating in the breast, lung, brain, and kidney. For my work, I decided to answer the question, “How does inhibition of QSOX1 effect the cancer phenotype?” To answer this I sought to fulfill the following goals A) determine the overexpression parameters of QSOX1 in cancer, B) identify QSOX1 small molecule inhibitors and their effect on the cancer phenotype, and C) determine potential biological effects of QSOX1 in cancer. Antibodies raised against rQSOX1 or a peptide from QSOX1-L were used to probe cancer cells of various origins for QSOX1 expression. High-throughput screening was utilized to identify 3-methoxy-n-[4(1pyrrolidinyl)phenyl]benzamide (SBI-183) as a lead inhibitor of QSOX1 enzymatic activity. Characterization of SBI-183 activity on various tumor cell lines revealed inhibition of viability and invasion in vitro, and inhibition of growth, invasion, and metastasis in vivo, a phenotype that was consistent with QSOX1 shKnockdown cells. Subsequent work identified 3,4,5-trimethoxy-N-[4-(1-pyrrolidinyl)phenyl]benzamide (SPX-009) as an SBI-183 analog with stronger inhibition of QSOX1 enzymatic activity, resulting in a more potent reduction in tumor invasion in vitro. Additional work with QSOX1 shKnockdown and Knockout (KO) cell lines confirmed current literature that QSOX1 is biologically active in modulation of the ECM. These results provide evidence for the master regulatory role of QSOX1 in cancer, making it an attractive chemotherapeutic target. Additionally, the small molecules identified here may prove to be useful probes in further elucidation of QSOX1 tumor biology and biomarker discovery.
ContributorsFifield, Amber (Author) / Lake, Douglas (Thesis advisor) / Ho, Thai (Committee member) / Rawls, Jeffery (Committee member) / Borges, Chad (Committee member) / Arizona State University (Publisher)
Created2020
Description
Cytometry is a method used to measure and collect the physical and chemical characteristics of a population of cells. In modern medical settings, the trend of precision and personalized medicines has imposed a need for rapid point-of-care diagnostic technologies. A rapid cytometric method, which aims at detecting and analyzing cells in direct patient samples, is therefore desirable. This dissertation presents the development of light-scattering-based imaging methods for detecting and analyzing cells and applies the technology in four applications. The first application is tracking phenotypic features of single particles, thereby differentiating bacterial cells from non-living particles in a label-free manner. The second application is a culture-free antimicrobial susceptibility test that rapidly tracks multiple, antimicrobial-induced phenotypic changes of bacterial cells with results obtained within 30 – 90 minutes. The third application is rapid antimicrobial susceptibility testing (AST) of bacterial cell growth directly in-patient urine samples, without a pre-culture step, within 90 min. This technology demonstrated rapid (90 min) detection of Escherichia coli in 24 clinical urine samples with 100% sensitivity and 83% specificity and rapid (90 min) AST in 12 urine samples with 87.5% categorical agreement with two antibiotics, ampicillin and ciprofloxacin. The fourth application is a multi-dimensional imaging cytometry system that integrates multiple light sources from different angles to simultaneously capture time-lapse, forward scattering and side scattering images of blood cells. The system has demonstrated capacity to detect red blood cell agglutination, assess red blood cell lysis, and differentiate red and white blood cells for potential implementation in clinical hematology analyses. These large-volume, light-scattering cytometric technologies can be used and applied in clinical and research settings to study, detect, and analyze cells. These studies developed rapid point-of-care diagnostic and imaging technologies for collectively advancing modern medicine and global health.
ContributorsMo, Manni (Author) / Borges, Chad (Thesis advisor) / Tao (Deceased), Nongjian (Thesis advisor) / Wang, Shaopeng (Committee member) / Chiu, Po-Lin (Committee member) / Haydel, Shelley (Committee member) / Arizona State University (Publisher)
Created2020