Biomedical Engineering and Bioengineering Commons^™

Atomic Force Microscopy Based Dna Sensing And Manipulation, Matthew Shubert

Mechanical Engineering Undergraduate Honors Theses

Sequencing DNA provides a positive impact for the biomedical community by understanding a wide variety of applications such as human genetics, disease, and pathogens. The reason the Arkansas Micro & Nano Systems lab is involved with research in DNA sequencing is due to the current, leading industry method. Nanopore sequencing was developed by Oxford Nanopore Technology in which its sequencing method separates double stranded DNA to electrically characterize individual nucleotides traveling through a charged nanopore. Unfortunately, nanopore sequencing uses biological materials that require a shelf life and drives high cost. Therefore, the Arkansas Micro & Nano Systems lab has developed …

Pulse Rate Variability Analysis During Hemorrhage In An Experimental Porcine Model, Gabbie Bonvillain, Lauren Crimmins, Md Abul Hayat, Adria Abella Villafranca, Sam Stephens, Hanna K. Jensen, Joseph A. Sanford, Jingxian Wu, Kevin W. Sexton, Morten Jensen

Biomedical Engineering Undergraduate Honors Theses

During the acute phase of hemorrhage, heart rate and peripheral resistance increases to maintain proper oxygen delivery to vital organs. This response is mediated by the autonomic nervous system. Heart rate variability (HRV) has become a widely utilized measure to determine the autonomic nervous system control over the heart. Recently, pulse rate variability (PRV) has been suggested to serve as a surrogate for HRV. This study evaluates the ability of PRV obtained from peripheral arterial pressure waveforms as a method for detecting hemorrhage. Time domain and frequency domain metrics were evaluated for 5-minute and 15-minute arterial pressure waveform signals prior …

Localized Intra-Arterial Drug Delivery Device For Stroke Treatment, Benjamin Yip

Biomedical Engineering Undergraduate Honors Theses

Strokes are one of the leading causes of death and long-term disability in the United States, and according to the Centers for Disease Control and Prevention more than 795,000 people experience a stroke every year. Around 87% of all strokes are ischemic strokes making it the most common form of stroke. While ischemic strokes are treatable, current devices and methods still result in high mortality rates and high risks of hemorrhaging after treatment. The aim of this study is to design and test a prototype of a novel device for the localized delivery of thrombolytics to treat ischemic strokes. The …

Nonviral Approaches For Delivery Of Crispr-Cas9 Into Hepatocytes For Treatment Of Inherited Metabolic Disease, Tanner R. Rathbone

All Dissertations

Inherited metabolic diseases (IMDs) of the liver have a collective occurrence of about 1 in 800 births. Current therapies for IMDs of the liver are limited, and the only curative option for patients is orthotopic liver transplantation. Due to shortages of organ donors, immunosuppression following the transplantation, and mortality risks associated with the procedure, alternative treatment options are necessary for curing IMDs of the liver. Therapeutic gene editing has been proposed as a potential strategy for treating IMDs of the liver. Adeno-associated viral vectors (AAVs) are the most widely used delivery method for liver-targeted gene therapies. Although widely used for …

Additive Manufacturing Of Variable Contrast Computed Tomography Anatomical Phantoms Using A Single Feedstock In Fused Filament Fabrication, Cory J. Darling

LSU New Orleans Theses and Dissertations

Anatomical phantoms used in biomedical education and training benefit greatly from Fused filament fabrication’s (FFF) ability to rapidly produce complex and unique models. Current materials and methods used in FFF have limited ability to accurately produce phantoms that can mimic the radiological properties of multiple biological tissues. This research demonstrates that the CT contrast of FFF produced models can be modified by varying the concentration of bismuth oxide in acrylonitrile butadiene styrene (ABS) filaments and a tunable CT contrast that mimics the CT contrast ranging from fatty tissue to cortical bone using a single composite filament without introducing artificial image …

Porous Silicon Photonics For Label-Free Interferometric Biosensing And Flat Optics, Tahmid Hassan Talukdar

All Dissertations

This dissertation uses porous silicon as a material platform to explore novel optical effects in three domains: (i) It studies dispersion engineering in integrated waveguides to achieve high performance group index sensing. With proper design parameters, the sensor waveguides can theoretically achieve 6 times larger group index shift compared to the actual bulk effective refractive index shift. We demonstrate the guided mode confinement factor to be a key parameter in design and implementation of these waveguides. (ii) It explores multicolor laser illumination to experimentally demonstrate perceptually enhanced colorimetric sensing, overcoming the limitations faced by many contemporary colorimetric sensors. Our technique …

Investigating The Effect Of Polymer Hydrogels On The Antimicrobial Properties Of Activated Carbon Through The Utilization Of Bacterial, Viral, And Parasitic Microorganisms, Zoe Gunter

Honors Theses

Activated carbon (AC) has long been utilized in biomedical applications due to its innate antimicrobial characteristics. However, little is understood about the mechanism of action that allows AC to prohibit the propagation of different pathogen species. To further ascertain these characteristics and how they affect the propagation of pathogens, procedures were designed with bacterial, viral, and parasitic agents which were utilized in conjunction with varying concentrations of polymer hydrogels to examine the antimicrobial efficacy of AC. The studies performed for this thesis were conducted employing coconut-based AC and Noveon^® AA-1 Polycarbophil USP or Carbopol^® 974P NF hydrogels which, …

Synthesis Of Monodisperse Nanoscintillators At High Temperatures For Biomedical Relevant Applications, Eric Zhang

All Dissertations

Luminescent sub-100 nm particulates continuously generate immense research interest in the biomedical field for imaging, theranostics, and optogenetics. Conventionally, upconversion nanoparticles or UV activated semiconductors are studied, however these materials are limited by biological barriers such as the skin which reduces the penetration depth of these excitation sources, tissue's auto- fluorescence, and toxicity. One approach to overcome these challenges is to use nanoscintillators (sub-100 nm materials that can generate visible light using high energy excitation sources such as x-rays) which can generate light locally to the human body. Numerous scintillators have been reported since the discovery of x-rays from the …

The Effects Of Metronomic And Maximum-Tolerated Dose Chemotherapy In Colorectal Cancer Angiogenesis: A Combined Approach Using Endoscopic Diffuse Reflectance Spectroscopy And Mrna Expression, Ariel Isaac Mundo Ortiz

Graduate Theses and Dissertations

Colorectal cancer (CRC) continues to be one of the most incident and deadliest types of cancer worldwide. Chemotherapy has proven effective to reduce tumor burden for CRC patients, but there are several disadvantages associated with the use of mainstay maximtolerated dose (MTD) chemotherapeutic strategies. Metronomic chemotherapy (MET) has been developed as an alternative that addresses the shortcomings of maximum-tolerated dose chemotherapy but so far its effectiveness as a neoadjuvant strategy for CRC has not been explored.

This dissertation uses a combined optics and molecular biology approach (using diffuse reflectance spectroscopy and mRNA expression) to study the changes in angiogenesis and …

Diffusive Dynamics Of Biological Macromolecules In The Cytoplasm Of Live Bacteria, Asmaa Sadoon

Graduate Theses and Dissertations

Bacteria are small organisms that play important roles in our bodies and in maintaining our surrounding environment. However, bacterial infections are considered as one of the health diseases that threatens the lives of humans. Resistance of bacteria to antibiotics has made treating bacterial infections more challenging. With the emergence of many developed optical techniques, it has become possible to study various biological mechanisms of molecules inside these small organisms with high resolution and precise localization. In this research, single particle tracking photoactivation localization microscopy (sptPALM) technique was used to investigate the dynamics of fluorescent histonelike nucleoid-structuring proteins (H-NS) in live …

Cyanobacterial And Microcystin Response To Nutrient Additions At Lake Fayetteville Throughout The 2021 Growing Season, Lillie Haddock

Graduate Theses and Dissertations

Harmful Algal Blooms (HABs) are becoming a global concern due to their increasing distribution, frequency, intensity, and the occurrence of toxins. While it is known that eutrophication influences algal blooms, there is less known about what triggers these HABs to produce toxins, especially microcystin. In this study, we conducted 21 community bioassays at Lake Fayetteville, a hypereutrophic reservoir in Fayetteville, Arkansas, from April-November 2021 to examine how the addition of phosphorous and nitrogen influence cyanobacteria concentrations, microcystin concentrations, and microcystin toxin production. These experiments included a control, nitrogen (1.0 mg/L as KNO3), low phosphorus (0.025 mg/L as K2HPO4), high phosphorus …

Development Of A Long-Read Sequencing Protocol To Assess The Precision And Efficacy Of Gene Editing For Duchenne Muscular Dystrophy, Landon Andrew Burcham

Graduate Theses and Dissertations

This work establishes a method for assessing on-target precision due to CRISPR-Cas9 gene editing, especially within the context of exon skipping therapy for Duchenne Muscular Dystrophy. The proposed method utilizes an Oxford nanopore long-read sequencing approach to sequence amplified regions of DNA that have been edited using CRISPR-Cas9. NIH3T3 and C2C12 cell lines were treated with a dual-guide CRISPR-Cas9 system, that targets and deletes exon 23 from the DMD gene in mouse samples. Deletion PCR revealed deletion of exon 23 in both DNA and cDNA samples. Additionally, sequencing using Oxford Nanopore revealed targeted exon 23 deletion as the most prevalent …

Machine Learning Approaches For Early Prediction Of Hypertension., Heba Elsayed Mohamed Kandil

Electronic Theses and Dissertations

Hypertension afflicts one in every three adults and is a leading cause of mortality in 516, 955 patients in USA. The chronic elevation of cerebral perfusion pressure (CPP) changes the cerebrovasculature of the brain and disrupts its vasoregulation mechanisms. Reported correlations between changes in smaller cerebrovascular vessels and hypertension may be used to diagnose hypertension in its early stages, 10-15 years before the appearance of symptoms such as cognitive impairment and memory loss. Specifically, recent studies hypothesized that changes in the cerebrovasculature and CPP precede the systemic elevation of blood pressure. Currently, sphygmomanometers are used to measure repeated brachial artery …

A Modeling Platform To Predict Cancer Survival And Therapy Outcomes Using Tumor Tissue Derived Metabolomics Data., Hunter Allan Miller

Electronic Theses and Dissertations

Cancer is a complex and broad disease that is challenging to treat, partially due to the vast molecular heterogeneity among patients even within the same subtype. Currently, no reliable method exists to determine which potential first-line therapy would be most effective for a specific patient, as randomized clinical trials have concluded that no single regimen may be significantly more effective than others. One ongoing challenge in the field of oncology is the search for personalization of cancer treatment based on patient data. With an interdisciplinary approach, we show that tumor-tissue derived metabolomics data is capable of predicting clinical response to …

Characterization Of Fundamental Parameters That Modulate Acoustofluidic-Mediated Molecular Delivery To Cells., Connor Sterling Centner

Electronic Theses and Dissertations

Cell-based therapies represent the latest biotechnological revolution in medicine, but significant limitations exist in non-viral intracellular delivery techniques during manufacturing of cell therapies. To address these limitations, a novel acoustofluidic device was developed to deliver ultrasound waves into a flow chamber for rapid molecular delivery to human cells. Our acoustofluidic device delivers biomolecules by inducing expansion and collapse of exogenous gas-filled microbubbles (“cavitation”), which enhances molecular delivery to nearby cells. Experimental studies were conducted to characterize key parameters that influence acoustofluidic-mediated molecular delivery to human cells. A clinical ultrasound transducer was generally utilized with varying cationic microbubble concentrations. Intracellular delivery …

Computer Vision And Machine Learning Applications In Cellular Images And Clinical Data, Guochang Ye

Theses and Dissertations

With the progressive development of artificial intelligence (AI), automated analysis has been explored for substituting tedious manual methods in cellular image analysis. Additionally, medical information not included in the conventional statistical methods is now being reconsidered with AI-based personalized medicine. The adaptivity and flexibility of AI ensure its efficiency and accuracy. In this work, computer vision and machine learning (ML) methods under the scope of AI are explicitly investigated and applied to cellular images and clinical data for cytological analysis and to provide diagnosis-based assistance/predictions. Firstly, novel computer vision algorithms achieve cell detection and differentiation estimation on phase-contact microscopic images …

Investigating Arrhythmia Potential In Cardiac Myocytes In Presence Of Long Qt Syndrome, Victoria Lin Lam

Biomedical Engineering Theses & Dissertations

Long QT Syndrome (LQTS) is an increasingly studied condition that leads to potentially fatal heart rhythm disorders, called arrhythmias, and sudden cardiac death. The alterations in the electrocardiograms (ECGs) seen in LQTS patients is caused by mutations to genes related to ion channels in cardiac cells. Computational modeling allows the mechanistic study of these ion channel mutations in LQTS by providing quantitative predictors of cardiac behavior in human and rabbit heart models. This work hypothesizes that the repolarization reserve in cardiac Purkinje cells (PC), that form the cardiac conduction system, is lower than that of ventricular myocytes (VM), resulting in …

Training The Responsible Conduct Of Research And Design, Jay R. Goldberg

Biomedical Engineering Faculty Research and Publications

Students Supported by grants from the National Institutes of Health (NIH) are required to complete training in the responsible conduct of research (RCR). This training includes topics such as authorship, handling of data, reporting of results, maintaining confidentiality, and other topics related to the ethical and responsible conduct of research. It prepares students who are supported by NIH research grants for careers involving research.

Fabrication And Characterization Of Lactobacillus Crispatus Containing Bioprints For Bacterial Vaginosis Application., Anthony J. Kyser

Electronic Theses and Dissertations

Bacterial vaginosis (BV) is a condition in which healthy lactobacilli are replaced by an overabundance of pathogenic bacteria in the female reproductive tract. Current antibiotic treatments often fail to “cure” infection, resulting in recurrence in more than 50% of women, 6 months post-treatment. Recently, probiotics have demonstrated promise to restore vaginal health; however, as with other active agents, delivery requires once-to-twice daily administration. Recently, three-dimensional (3D)-bioprinting has enabled the fabrication of well-defined cell-laden architectures with tunable agent release, thereby presenting a novel approach with which to deliver probiotics. One promising bioink, gelatin alginate, was selected for study, due to its …

Release Kinetics Of Metronidazole From 3d Printed Silicone Scaffolds., Sydney E. Herold

Electronic Theses and Dissertations

Sustained local administration of active agents has been proposed to cure bacterial vaginosis in the female reproductive tract and restore the resident bacterial fauna. Bioprinting has shown promise for the development of systems for local agent delivery. In contrast to oral ingestion, agent release kinetics can be fine-tuned by bioprinting specialized scaffold designs tailored for particular treatments while enhancing dosage effectiveness via localized sustained release. It has been challenging to establish scaffold properties for sustained release as a function of fabrication parameters. Towards this goal, we evaluate 3D printed scaffold formulation and feasibility to sustain release of metronidazole, a representative …