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- All Subjects: Biomedical Engineering
- Creators: Arizona State University
Description
Characterizing and identifying neuroinflammatory states is crucial in developing treatments for neurodegenerative diseases. Microglia, the resident immune cells of the brain, regulate inflammation and play a vital role in maintaining brain health by producing cytokines, performing phagocytosis, and inducing or reducing inflammation. These functional states can be described by specific patterns of gene expression called transcriptional programs, which are determined by the activity of a set of key transcription factors that have mostly been identified. Thus, an assay for transcription factor activity could reveal the state of the microglial cells and neuroinflammation across the brain. This research developed an assay that uses a transcription factor dependent reporter to indicate which transcriptional programs are activated in the cell when exposed to different stimuli. The prototype assay quantifies nuclear factor kappa B (NF-kB) response in cultured human cells. NF-kB is a well-characterized transcription factor associated with inflammatory pathways in most cells, including microglia. The reporter construct contains an NF-kB specific responsive element that can induce fluorescence/luminescence upon activation of the transcription factor. In an iterative refinement, a dual response fluorescent reporter was developed, which uses a secondary constitutively fluorescent reporter for built-in normalization of the responsive element for microscopy studies. With further refinement, this modular system will serve as a template for less understood transcriptional enhancers allowing for rapid, low-cost assays of neuroimmune regulators and potential in vivo applications in the study of neuroinflammation.
ContributorsLieberman, Emma (Author) / Bartelle, Benjamin B (Thesis advisor) / Plaisier, Christopher L (Committee member) / Andrews, Madeline G (Committee member) / Arizona State University (Publisher)
Created2023
Description
Chimeric antigen receptor (CAR)-T cell therapy is a type of cancer immunotherapy has shown promising results in engineering the T cells which targets a specific antigen. Despite their success rate, there are certain limitations to the use of CAR-T therapies that includes cytokine release syndrome (CRS), neurologic toxicity, lack of response in approximately 50% of treated patients, monitoring of patients treated with CAR-T therapy. However, rapid point- of- care testing helps in quantifying the circulating CAR T cells and can enhance the safety of patients, minimize the cost of CAR-T cell therapy, and ease the management process. Currently, the standard method to quantify CAR-T cell in patient blood samples are flow cytometry and quantitative polymerase chain reaction (qPCR). But these techniques are expensive and are not easily accessible and suitable for point- of- care testing to assist real- time clinical decisions. To overcome these hurdles, here I propose a solution to these problems by rapid optical imaging (ROI)- based principle to monitor and detect CAR-T cells. In this project, a microfluidic device is developed and integrated with two functions: (1) Centrifuge free, filter- based separation of white blood cells and plasma; (2) Optical imaging- based technique for digital counting of CAR T- cells. Here, I carried out proof- of- concept test on the laser cut prototype microfluidic chips as well as the surface chemistry for specific capture of CAR-T cells. These data show that the microfluidic chip can specifically capture CAR-T positive cells with concentration dependent counts of captured cells. Further development of the technology could lead to a new tool to monitor the CAR-T cells and help the clinicians to effectively measure the efficacy of CAR-T therapy treatment in a faster and safer manner.
ContributorsElanghovan, Praveena (Author) / Wang, Shaopeng (Thesis advisor) / Forzani, Erica (Committee member) / Nikkhah, Mehdi (Committee member) / Arizona State University (Publisher)
Created2023
Description
Low back pain (LBP) is the most common symptom leading to hospitalization and medical assistance. In the US, LBP is the fifth most prevalent case for visiting hospitals. Approximately 2.06 million LBP incidents were reported during the timeline between 2004 and 2008. Globally, LBP occurrence increased by almost 200 million from 1990 to 2017. This problem is further implicated by physical and financial constraints that impact the individual’s quality of life. The medical cost exceeded $87.6 billion, and the lifetime prevalence was 84%. This indicates that the majority of people in the US will experience this symptom. Also, LBP limits Activities of Daily Living (ADL) and possibly affects the gait and postural stability. Prior studies indicated that LBP patients have slower gait speed and postural instability. To alleviate this symptom, the epidural injection is prescribed to treat pain and improve mobility function. To evaluate the effectiveness of LBP epidural injection intervention, gait and posture stability was investigated before and after the injection. While these factors are the fundamental indicator of LBP improvement, ADL is an element that needs to be significantly considered. The physical activity level depicts a person’s dynamic movement during the day, it is essential to gather activity level that supports monitoring chronic conditions, such as LBP, osteoporosis, and falls. The objective of this study was to assess the effects of Epidural Steroid Injection (ESI) on LBP and related gait and postural stability in the pre and post-intervention status. As such, the second objective was to assess the influence of ESI on LBP, and how it influences the participant’s ADL physical activity level. The results indicated that post-ESI intervention has significantly improved LBP patient’s gait and posture stability, however, there was insufficient evidence to determine the significant disparity in the physical activity levels. In conclusion, ESI depicts significant positive effects on LBP patients’ gait and postural parameters, however, more verification is required to indicate a significant effect on ADL physical activity levels.
ContributorsMoon, Seong Hyun (Author) / Lockhart, Thurmon (Thesis advisor) / Honeycutt, Claire (Committee member) / Peterson, Daniel (Committee member) / Lee, Hyunglae (Committee member) / Soangra, Rahul (Committee member) / Arizona State University (Publisher)
Created2023
Description
A current thrust in neurorehabilitation research involves exogenous neuromodulation of peripheral nerves to enhance neuroplasticity and maximize recovery of function. This dissertation presents the results of four experiments aimed at assessing the effects of trigeminal nerve stimulation (TNS) and occipital nerve stimulation (ONS) on motor learning, which was behaviorally characterized using an upper extremity visuomotor adaptation paradigm. In Aim 1a, the effects of offline TNS using clinically tested frequencies (120 and 60 Hz) were characterized. Sixty-three participants (22.75±4.6 y/o), performed a visuomotor rotation task and received TNS before encountering rotation of hand visual feedback. In Aim 1b, TNS at 3 kHz, which has been shown to be more tolerable at higher current intensities, was evaluated in 42 additional subjects (23.4±4.6 y/o). Results indicated that 3 kHz stimulation accelerated learning while 60 Hz stimulation slowed learning, suggesting a frequency-dependent effect on learning. In Aim 2, the effect of online TNS using 120 and 60 Hz were characterized to determine if this protocol would deliver better outcomes. Sixty-three participants (23.2±3.9 y/o) received either TNS or sham concurrently with perturbed visual feedback. Results showed no significant differences among groups. However, a cross-study comparison of results obtained with 60 Hz offline TNS showed a statistically significant improvement in learning rates with online stimulation relative to offline, suggesting a timing-dependent effect on learning. In Aim 3, TNS and ONS were compared using the best protocol from previous aims (offline 3 kHz). Additionally, concurrent stimulation of both nerves was explored to look for potential synergistic effects. Eighty-four participants (22.9±3.2 y/o) were assigned to one of four groups: TNS, ONS, TNS+ONS, and sham. Visual inspection of learning curves revealed that the ONS group demonstrated the fastest learning among groups. However, statistical analyses did not confirm this observation. In addition, the TNS+ONS group appeared to learn faster than the sham and TNS groups but slower than the ONS only group, suggesting no synergistic effects using this protocol, as initially hypothesized.
The results provide new information on the potential use of TNS and ONS in neurorehabilitation and performance enhancement in the motor domain.
ContributorsArias, Diego (Author) / Buneo, Christopher (Thesis advisor) / Schaefer, Sydney (Committee member) / Helms-Tillery, Stephen (Committee member) / Santello, Marco (Committee member) / Kleim, Jeffrey (Committee member) / Arizona State University (Publisher)
Created2023
Description
Over the past 20 years, the fields of synthetic biology and synthetic biosystems engineering have grown into mature disciplines, leading to significant breakthroughs in cancer research, diagnostics, cell-based medicines, biochemical production, etc. Application of mathematical modelling to biological and biochemical systems have not only given great insight into how these systems function, but also have lent enough predictive power to aid in the forward-engineering of synthetic constructs. However, progress has been impeded by several modes of context-dependence unique to biological and biochemical systems that are not seen in traditional engineering disciplines, resulting in the need for lengthy design-build-test cycles before functional prototypes are generated.In this work, two of these universal modes of context dependence – resource competition and growth feedback –their effects on synthetic gene circuits and potential control mechanisms, are studied and characterized. Results demonstrate that a novel competitive control architecture can be utilized to mitigate the effects of winner-take-all resource competition (a form of context dependence where distinct gene modules influence each other by competing over a shared pool of transcriptional/translational resources) in synthetic gene circuits and restore circuits to their intended function. Application of the fluctuation-dissipation theorem and rigorous stochastic simulations demonstrate that realistic resource constraints present in cells at the transcriptional and translational levels influence noise in gene circuits in a nonmonotonic fashion, either increasing or decreasing noise depending on the transcriptional/translational capacity.
Growth feedback on the other hand links circuit function to cellular growth rate via increased protein dilution rate during exponential growth phase. This in turn can result in the collapse of bistable gene circuits as the accelerated dilution rate forces switches in a high stable state to fall to a low stable state. Mathematical modelling and experimental data demonstrate that application of repressive links can insulate sensitive parts of gene circuits against growth-fluctuations and can in turn increase the robustness of multistable circuits in growth contexts.
The results presented in this work aid in the accumulation of understanding of biological and biochemical context dependence, and corresponding control strategies and design principles engineers can utilize to mitigate these effects.
ContributorsStone, Austin (Author) / Tian, Xiao-jun (Thesis advisor) / Wang, Xiao (Committee member) / Smith, Barbara (Committee member) / Kuang, Yang (Committee member) / Cheng, Albert (Committee member) / Arizona State University (Publisher)
Created2023
Description
Evolving knowledge about the tumor microenvironment (TME) is driving innovation in designing novel therapies against hard-to-treat breast cancer. Addressing the immune elements within the tumor microenvironment (TME) has emerged as a highly encouraging strategy for treating cancer. Although current immunotherapies have made advancements in reinstating the body's ability to fight tumors, the search for effective cancer treatments to combat tumor evasion remains a formidable challenge. In line with this objective, there is a pressing need to better understand the complex tumor-immune dynamics and crosstalk within the TME. To evaluate the cancer-immune interaction, this study aimed at investigating the crosstalk between naïve macrophages and cytotoxic T cells in driving tumor progression using an organotypic 3D ex vivo tumor on-a-chip model. The presented microfluidic platform consists of two distinct regions namely: The tumor region and the stroma region separated by trapezoidal microposts to ensure interconnectivity between regions thereby incorporating high spatial organization. In the established triculture platform, the complex Tumor Immune Microenvironment was successfully recapitulated by incorporating naïve macrophage and T cells within an appropriate 3D matrix. Through invasion and morphometric analyses, definitive outcomes were obtained that underscore the significant contribution of macrophages in facilitating tumor progression. Furthermore, the inclusion of T cells led to a notable decrease in the migratory speed of cancer cells and macrophages, underscoring the reciprocal communication between these two immune cell populations in the regulation of tumor advancement. Overall, this study highlights the complexity of TME and underscores the critical role of immune cells in regulating cancer progression.
ContributorsManoharan, Twinkle Jina Minette (Author) / Nikkhah, Mehdi (Thesis advisor) / Acharya, Abhinav P (Committee member) / Wang, Shaopeng (Committee member) / Arizona State University (Publisher)
Created2023
Description
Multisensory integration is the process by which information from different sensory modalities is integrated by the nervous system. This process is important not only from a basic science perspective but also for translational reasons, e.g., for the development of closed-loop neural prosthetic systems. A mixed virtual reality platform was developed to study the neural mechanisms of multisensory integration for the upper limb during motor planning. The platform allows for selection of different arms and manipulation of the locations of physical and virtual target cues in the environment. The system was tested with two non-human primates (NHP) trained to reach to multiple virtual targets. Arm kinematic data as well as neural spiking data from primary motor (M1) and dorsal premotor cortex (PMd) were collected. The task involved manipulating visual information about initial arm position by rendering the virtual avatar arm in either its actual position (veridical (V) condition) or in a different shifted (e.g., small vs large shifts) position (perturbed (P) condition) prior to movement. Tactile feedback was modulated in blocks by placing or removing the physical start cue on the table (tactile (T), and no-tactile (NT) conditions, respectively). Behaviorally, errors in initial movement direction were larger when the physical start cue was absent. Slightly larger directional errors were found in the P condition compared to the V condition for some movement directions. Both effects were consistent with the idea that erroneous or reduced information about initial hand location led to movement direction-dependent reach planning errors. Neural correlates of these behavioral effects were probed using population decoding techniques. For small shifts in the visual position of the arm, no differences in decoding accuracy between the T and NT conditions were observed in either M1 or PMd. However, for larger visual shifts, decoding accuracy decreased in the NT condition, but only in PMd. Thus, activity in PMd, but not M1, may reflect the uncertainty in reach planning that results when sensory cues regarding initial hand position are erroneous or absent.
ContributorsPhataraphruk, Preyaporn Kris (Author) / Buneo, Christopher A (Thesis advisor) / Zhou, Yi (Committee member) / Helms Tillery, Steve (Committee member) / Greger, Bradley (Committee member) / Santello, Marco (Committee member) / Arizona State University (Publisher)
Created2023
Description
Finite element models (FEMs) of spine segments validated in their intact states are often used to make predictions following structural modifications simulating surgical procedures, including posterior fusion with pedicle screws and rods (PSR) and laminectomy (removal of posterior column bone to decompress the spinal cord). The gold standard for spine FEM validation compares predicted vs. experimental intervertebral ranges of motion (ROM). Given that muscle co-contraction compresses the spine, validation that considers compression may produce a more robust FEM. One research goal was to evaluate an experimental method of compressing a lumbar spine segment through its sagittal plane balance (pivot) point (BP) using a 6DOF robotic test system. Experimental data supported the hypothesis that structural modifications, such as PSR and laminectomy alter the segment’s BP location and its compressive stiffness. However, evaluation showed that the experimental BP method is sensitive to specimen posture in the robotic test frame; slight flexion or extension produced shear loads during compression that affect BP location and should be included in specimen-specific FEMs to ensure similar load conditions. Another goal was to develop a uniquely calibrated specimen-specific FEM of an intact L4-5 motion segment using the experimental BP data. A specimen-specific FEM was created and calibrated using experimental BP compressive stiffness data, however matching experimental BP location data was unsuccessful. The BP-compression calibrated FEM was evaluated by comparing predicted responses to loads following simulated PSR and laminectomy to specimen-specific experimental data. Predictions using the BP-calibrated and ROM-calibrated FEMs were compared. The BP-calibration process helped identify an unrealistic FEM disc geometry (nucleus pulposus size and location). Both BP-compression and ROM-calibrated FEMs predicted effects of PSR on stiffness (compressive and flexural) that were greater than experimental, which helped identify a problem with simplified representations of bone in the posterior column and at the anterior column interface. The BP-compression calibrated FEMs predicted relative shifts in BP locations and bone surface strains during compression that were closer to experimental data than similarly modified ROM-calibrated FEMs. Collectively, these results support the use of BP measures in experimental and model-based investigations of surgical modifications of the spine.
ContributorsSawa, Anna Genowefa Ulrika (Author) / Abbas, James (Thesis advisor) / Crawford, Neil R (Thesis advisor) / Kelly, Brian P (Committee member) / Helms-Tillery, Stephen (Committee member) / Sadleir, Rosalind (Committee member) / Arizona State University (Publisher)
Created2023
Description
Non-invasive biosensors enable rapid, real-time measurement and quantification of biological processes, such as metabolic state. Currently, the most accurate metabolic sensors are invasive, and significant cost is required, with few exceptions, to achieve similar accuracy using non-invasive methods. This research, conducted within the Biodesign Institute Center for Bioelectronics and Biosensors, leverages the selective reactivity of a chemical sensing solution to develop a sensor which measures acetone in the breath for ketosis and ketoacidosis diagnostics, which is relevant to body weight management and type I diabetes. The sensor displays a gradient of color changes, and the absorbance change is proportional to the acetone concentration in the part- per-million range, making applicable for detection ketosis and ketoacidosis in human breath samples. The colorimetric sensor response can be fitted to a Langmuir-like model for sensor calibration. The sensors best performance comes with turbulent, continuous exposure to the samples, rather than batch sample exposure. With that configuration, these novel sensors offer significant improvements to clinical and at- home measurement of ketosis and ketoacidosis.
ContributorsDenham, Landon (Author) / Forzani, Erica (Thesis advisor) / Wang, Shaopeng (Committee member) / Kulick, Doina (Committee member) / Arizona State University (Publisher)
Created2023
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