Medicine and Health Sciences Commons^™

Chemical Modification And Evaluation Of Cells Towards Use As Delivery Tools, Bishnu Prasad Joshi

Doctoral Dissertations

CHEMICAL MODIFICATION AND EVALUATION OF CELLS TOWARDS USE AS DELIVERY TOOLS SEPTEMBER 2023 BISHNU PRASAD JOSHI M.S., SRI SATHYA SAI INSTITUTE OF HIGHER LEARNING Ph.D., UNIVERSITY OF MASSACHUSETTS AMHERST Directed by: Professor Michelle E. Farkas Endogenous cells are being studied for use in various applications, such as next generation therapeutics and drug delivery vehicles. This is on account of their biocompatibility, amenable distribution profiles, and in many instances, recruitment to and localization of diseased tissues. Multiple cell types have been employed, including macrophages, stem cells, red blood cells, and T cells. Most examples of cell-based delivery utilize phagocytosed entities as …

Mechanism-Driven Approaches And Novel Constructs For High Purity Rna Synthesis, Kithmie Malagodapathiranage

Doctoral Dissertations

RNA is poised to revolutionize medicine. By simply changing the sequence, one therapeutic can be converted into a wholly new one, with little or no change in manufacturing and formulation. While a single mRNA vaccine produced at massive scale can treat billions, the re-codability of RNA will also enable the widespread growth of personalized medicines. T7 RNA polymerase is highly efficient at the synthesis of therapeutic RNA, but is known to produce unintended RNA impurities during synthesis. These products arise from the encoded RNA rebinding the enzyme such that its 3’ end serves as a primer for extension. This leads …

Frontiers In The Self-Assembly Of Charged Macromolecules, Khatcher O. Margossian

Doctoral Dissertations

The self-assembly of charged macromolecules forms the basis of all life on earth. From the synthesis and replication of nucleic acids, to the association of DNA to chromatin, to the targeting of RNA to various cellular compartments, to the astonishingly consistent folding of proteins, all life depends on the physics of the organization and dynamics of charged polymers. In this dissertation, I address several of the newest challenges in the assembly of these types of materials. First, I describe the exciting new physics of the complexation between polyzwitterions and polyelectrolytes. These materials open new questions and possibilities within the context …

Biomedical Applications Of Protein Films And Polymeric Nanomaterials, Sanjana Gopalakrishnan

Doctoral Dissertations

Biomaterials are widely applied for the diagnosis and treatment of numerous diseases. In addition to fulfilling specific biological functions, biomaterials must also be non-toxic, biocompatible, and sterilizable to be regarded as safe-for-use. Polymers are excellent candidates for fabricating functional biomaterials due to their wide availability and varied properties and may be natural or synthetic. Polymer precursors are fabricated into coatings, foams, scaffolds, gels, composites, and nanomaterials for several biomedical applications. This dissertation focuses on two types of polymeric biomaterials – protein-based materials and synthetic polymeric nanoparticles. Proteins are biopolymers that naturally occur with a variety of structural and functional properties. …

Protein Detection And Structural Characterization By Mass Spectrometry Using Supramolecular Assemblies And Small Molecules, Bo Zhao

Doctoral Dissertations

Mass spectrometry (MS) has played an increasingly prominent role in proteomics and structure biology because it shows superior capabilities in identification, quantification and structural characterization of proteins. To realize its full potential in protein analysis, significant progress has been made in developing innovative techniques and reagents that can couple to MS detection. This dissertation demonstrates the use of polymeric supramolecular assemblies for enhanced protein detection in complex biological mixtures by MS. An amphiphilic random co-polymer scaffold is developed to form functional supramolecular assemblies for protein/ peptide enrichment. The influences of charge density and functional group pK_a on host-guest interactions …

Engineering Nanomaterials For Imaging And Therapy Of Bacteria And Biofilm-Associated Infections, Akash Gupta

Doctoral Dissertations

Infections caused by multidrug-resistant (MDR) bacteria pose a serious global burden of mortality, causing thousands of deaths each year. The “superbug” risk is further exacerbated by chronic infections generated from antibiotic-resistant biofilms that are highly resistant to available treatments. Synthetic macromolecules such as polymers and nanoparticles have emerged as promising antimicrobials. Moreover, ability to modulate nanomaterial interaction with bacterial cellular systems plays a pivotal role in improving the efficacy of the strategy. In the initial studies on engineering nanoparticle surface chemistry, I investigated the role played by surface ligands in determining the antimicrobial activity of the nanoparticles. In further study, …

Game-Assisted Rehabilitation For Post-Stroke Survivors, Hee-Tae Jung

Doctoral Dissertations

Stroke is a leading cause of permanent impairments among its survivors. Although patients need to go through intensive, longitudinal rehabilitation to regain function before the stroke, patients show poor engagement and adherence to rehabilitation therapies which hampers their recovery. As a means to enhance stroke survivors' motivation, engagement, and adherence to intensive and longitudinal rehabilitation, the use of games in stroke rehabilitation has received attention from research and clinical communities. In order to realize this, it is important to take a holistic, end-to-end research approach that encompasses 1) the development of game technologies that are not only entertaining but also …

Hybridized Polymeric Nano-Assemblies: Key Insights Into Addressing Mdr Infections, Ryan Landis

Doctoral Dissertations

Multidrug-resistant (MDR) bacteria contribute to more than 700,000 annual deaths world-wide. Millions more suffer from limb amputations or face high healthcare treatment costs where prolonged and costly therapeutic regimens are used to counter MDR infections. While there is an international push to develop novel and more powerful antimicrobials to address the impending threat, one particularly interesting approach that has re-emerged are essential oils, phytochemical extracts derived from plant sources. While their antimicrobial activity demonstrates a promising avenue, their stability in aqueous media, limits their practical use in or on mammals. Inspired by the versatility of polymer nanotechnology and the sustainability …

Direct Printing Of Conductive Inks For Organic Electronics And Wearable Microfluidics, Aditi Naik

Doctoral Dissertations

This dissertation examines the direct printing of conductive inks on polymeric substrates for applications in organic electronics, microfluidic valving systems, and wearable sweat sensors. The inexpensive production of solution-based electrodes with high electrical conductivity is necessary to enable the next-generation of printed, flexible, and organic electronics. Specifically, the optimization and printing of liquid-phase graphene ink and nanoparticle-based silver ink by soft nanoimprint lithography and inkjet-printing is discussed to achieve printed functional devices. Using scalable low-cost patterning systems, these flexible applications are compatible with roll-to-roll processing, enabling large-scale manufacturing. This research expands the knowledge of high-resolution printing optimization for the direct …

Investigating The Regulation Of Indole-3-Acetic Acid Production By The Plant Associated Microbe Pantoea Sp. Yr343, Kasey Noel Estenson

Doctoral Dissertations

The auxin indole-3-acetic acid (IAA) plays a central role in plant growth and development and many plant-associated microbes produce IAA. Several IAA biosynthetic pathways have been identified in microbes which use the precursor tryptophan. Pantoea sp. YR343, which was isolated from the Populus deltoides rhizosphere, is a robust plant root colonizer that produces IAA. Using genomic and metabolomics analyses, we predicted that the indole-3-pyruvate (IPA) pathway is the major pathway in Pantoea sp. YR343 for IAA production. To better understand IAA biosynthesis and the effects of IAA exposure on cell physiology, we performed proteomics on Pantoea sp. YR343 grown in …

Robust Biosensors For Healthcare Applications: From High-Content Screening To Point-Of-Care Testing, Ngoc D. B. Le

Doctoral Dissertations

Efficient detection of proteins, mammalian cells, microorganisms and other biological systems in complex mixture is essential in disease diagnosis and environmental health. Therefore, technological platforms that provide sensors of high sensitivity, selectivity and stability are greatly desired. Recently, the ‘chemical-nose’ sensing approach has proved to be an effective strategy for profiling bio-relevant targets in complex mixtures. Detecting analytes in complex mixture is a challenge that conventional specificity-based sensors are still trying to solve due to the requirement of prior knowledge of the analyte, which is unknown in many cases. This thesis focuses on how to develop simple and robust …

Colicins - A Sound Antimicrobial Approach For The Prevention Of Catheter-Associated Urinary Tract Infections, Sandra M. Roy

Doctoral Dissertations

The emergence and spread of antibiotic resistance has created one of the greatest challenges in fighting infectious disease. We address the rise of antibiotic-resistant pathogens by examining the evolutionary history of a class of resistance determinants, the SHV b-lactamases. We isolated the genes that encode the SHV beta-lactamases (bla_SHV genes) from clinical settings and from an environment essentially devoid of antibiotic use. Our data suggests that, counter to current dogma, the use of antibiotics in the clinic is not creating these resistance genes; genes for antibiotic resistance already exist in nature and our use of antibiotics in clinical …

Development Of A Patient Machine Time Model To Evaluate Dose Perturbation By Respiratory Tumor Motion In Pencil Beam Scanning Proton Radiation Therapy, Mark Artz

Doctoral Dissertations

The pencil beam scanning (PBS) modality for delivering intensity modulated proton radiation therapy is being adopted quickly. Drawing from the dosimetric advantages provided by the Bragg Peak, PBS proton therapy has been shown to produce dose distributions with improved healthy tissue sparing.

Although PBS proton therapy is very promising, lung cancer treatment is not without its challenges. Rapid tissue density changes and respiratory tumor motion present a particularly difficult treatment geometry. The tumor moves continuously within the lung as the patient breathes.

In this project, the dose perturbation of a PBS proton therapy lung plan is evaluated and time based …

Engineering Novel Detection And Treatment Strategies For Bacterial Therapy Of Cancer, Jan T. Panteli

Doctoral Dissertations

Finding and treating cancer is difficult due to limited sensitivity and specificity of current detection and treatment strategies. Many chemotherapeutic drugs are small molecules that are limited by diffusion, making it difficult to reach cancer sites requiring high doses that lead to systemic toxicity and off-target effects. Tomographic detection techniques, like PET, MRI and CT, are good at identifying macroscopic lesions in the body but are limited in their ability to detect microscopic lesions. Biomarker detection strategies are extremely sensitive and able to identify ng/ml concentrations of protein, but are poor at discriminating between healthy and disease state levels due …

Dynamic Simulation And Neuromuscular Control Of Movement: Applications For Predictive Simulations Of Balance Recovery, Misagh Mansouri Boroujeni

Doctoral Dissertations

Balance is among the most challenging tasks for patients with movement disorders. Study and treatment of these disorders could greatly benefit from combined software tools that offer better insights into neuromuscular biomechanics, and predictive capabilities for optimal surgical and rehabilitation treatment planning. A platform was created to combine musculoskeletal modeling, closed-loop forward dynamic simulation, optimization techniques, and neuromuscular control system design. Spinal (stretch-reflex) and supraspinal (operational space task-based) controllers were developed to test simulation-based hypotheses related to balance recovery and movement control. A corrective procedure (rectus femoris transfer surgery) was targeted for children experiencing stiff-knee gait and how this procedure …

Ligand-Receptor Interactions For Supramolecular Disassembly With Applications In Screening And Drug Delivery, Diego Amado Torres

Doctoral Dissertations

Proteins have the capacity to bind specific sets of compounds known as ligands, these are small molecules with a recurrent theme in their molecular design that is a characteristic exploited here to (i) identify particular affinities of small molecules for proteins with the aim of using them as ligands, inhibitors, or targeting moieties in more complex systems by means of a methodology that screens small molecules based on protein affinity; (ii) decorate a self-assembling supramolecular system at different positions, making it responsive to a complementary protein with the aim of exploring differences in disassembly and sensitivity of the release of …

Virtual Reality Aided Mobile C-Arm Positioning For Image-Guided Surgery, Zhenzhou Shao

Doctoral Dissertations

Image-guided surgery (IGS) is the minimally invasive procedure based on the pre-operative volume in conjunction with intra-operative X-ray images which are commonly captured by mobile C-arms for the confirmation of surgical outcomes. Although currently some commercial navigation systems are employed, one critical issue of such systems is the neglect regarding the radiation exposure to the patient and surgeons. In practice, when one surgical stage is finished, several X-ray images have to be acquired repeatedly by the mobile C-arm to obtain the desired image. Excessive radiation exposure may increase the risk of some complications. Therefore, it is necessary to develop a …

Immunologic Risk Prediction Model For Kidney Graft Function, Christina Diane Bishop

Doctoral Dissertations

Clinicians lack appropriate non-invasive methods to be able to predict, diagnose, and reduce the risk of rejection in the years following kidney transplantation. Protocol biopsies and monitoring of serum creatinine levels are the most common methods of monitoring graft function after transplant; however, they have several negative aspects. Use of traditional factors regarding donors and recipients such as Human Leukocyte Antigen (HLA) DNA typing, pre-transplant anti-HLA antibody levels, and basic demographics (age, ethnicity/race, gender), has proved inadequate for post-transplant graft monitoring past the first few years. We propose that by utilizing immunologic factors available to clinicians across the United States, …

Development Of An Autonomous Mammalian Lux Reporter System, Daniel Michael Close

Doctoral Dissertations

Since its characterization, the definitive shortcoming of the bacterial luciferase (lux) bioluminescent reporter system has been its inability to express at a functional level in the eukaryotic cellular background. While recent developments have allowed for lux function in the lower eukaryote Saccharomyces cerevisiae, they have not provided for autonomous function in higher eukaryotes capable of serving as human biomedical proxies. Here it is reported for the first time that, through a process of poly-bicistronic expression of human codon-optimized lux genes, it is possible to autonomously produce a bioluminescent signal directly from mammalian cells. The low background of …