Molecular, Cellular, and Tissue Engineering Commons^™

Experimental And Model-Based Terahertz Imaging And Spectroscopy For Mice, Human, And Phantom Breast Cancer Tissues, Tyler Bowman

Graduate Theses and Dissertations

The goal of this work is to investigate terahertz technology for assessing the surgical margins of breast tumors through electromagnetic modeling and terahertz experiments. The measurements were conducted using a pulsed terahertz system that provides time and frequency domain signals. Three types of breast tissues were investigated in this work. The first was formalin-fixed, paraffin-embedded tissues from human infiltrating ductal and lobular carcinomas. The second was human tumors excised within 24-hours of lumpectomy or mastectomy surgeries. The third was xenograft and transgenic mice breast cancer tumors grown in a controlled laboratory environment to achieve more data for statistical analysis.

Experimental …

Effects Of Uniaxial Cyclic Strain On Endothelial Progenitor Cells, Maria Alejandra Zeballos Castro

Biomedical Engineering Undergraduate Honors Theses

Despite the high prevalence of calcific aortic valve disease (CAVD), the underlying mechanisms of pathogenesis have not been found yet. Therefore, it is extremely important to study CAVD and understand how it develops. For this matter, we decided to study the potential of endothelial progenitor cells (EPCs) for use in tissue-engineered models of heart valves. EPCs were chosen as the cell source of interest for this study due to their high neovascularization potential and use in regenerative medicine and cardiovascular tissue engineering.

In this project, we aimed to engineer the microenvironment of cells that are involved in the formation of …

Intravenous Administration Of Iron Oxide Nanoparticles In The Chicken Model, Huong Thi Ngoc Le

Graduate Theses and Dissertations

To be used in health care, the safety and effectiveness of nanoparticles needs to be tested in a living organism. The objective of this project was to develop the chicken as a convenient animal model to examine tissue targeting of intravenously (i.v.)-injected iron oxide (IO) nanoparticles. In Experiment 1, different doses of IO-COOH were i.v. injected into chickens; blood was collected at 0, 5, 15, 30, and 60 minutes post-injection; liver, spleen, lung, and kidney were collected after the last blood collection. For Experiment 2, IO-COOH and IO-PEG were i.v. injected into chickens; blood and the organs were collected at …

Age's Effect On Regenerative Capabilities Of Myocytes Through Satellite Cell Analysis, Karam S. Sra

Biomedical Engineering Undergraduate Honors Theses

The objective of this study was to investigate potential effects aging had on muscle fiber area and satellite cell count in myocytes. This research could help elucidate the detrimental effect age has on regenerative capabilities whether in terms of satellite cell function or satellite cell number. Satellite cells are primarily responsible for generating new muscle tissue after being activated through mechanotransduction of injury. This study utilized immunofluorescence to examine the presence of the PAX7 gene expression, a unique marker of satellite cells, within a 12 month and 18 month old population of mice. The PAX7 marker was co-stained with DAPI …

Detection Of Leukocytes Stained With Acridine Orange Using Unique Spectral Features Acquired From An Image-Based Spectrometer, Courtney J. Hunter

Biomedical Engineering Undergraduate Honors Theses

A leukocyte differential count can be used to diagnosis a myriad blood disorders, such as infections, allergies, and efficacy of disease treatments. In recent years, attention has been focused on developing point-of-care (POC) systems to provide this test in global health settings. Acridine orange (AO) is an amphipathic, vital dye that intercalates leukocyte nucleic acids and acidic vesicles. It has been utilized by POC systems to identify the three main leukocyte subtypes: granulocytes, monocytes, and lymphocytes. Subtypes of leukocytes can be characterized using a fluorescence microscope, where the AO has a 450 nm excitation wavelength and has two peak emission …

Characterization Of The Response Of Trpv4 To Chemical Stimulation, Jacob V. Schluns

Biomedical Engineering Undergraduate Honors Theses

Traumatic Brain Injury (TBI) is a source of acute and chronic health issues for many patients. One of the components of the brain’s response to injury is astrogliosis, in which astrocytes that normally function to repair the brain instead form scar tissue that halts repair processes. Transient Receptor Potential Vanilloid Type 4 (TRPV4) is a trans-membrane calcium channel involved in astrogliosis. Through Fura-2AM based calcium imaging, the base activity of this channel in mouse astrocyte cells was recorded. The cells were then subjected to TRPV4 agonist and antagonist stimulation and their subsequent activity levels were recorded. The data showed that …

Role Of Trpv4 In Astrocyte Extracellular Matrix Production, Abby Terlouw

Biomedical Engineering Undergraduate Honors Theses

Traumatic Brain Injury (TBI) is an alteration of brain pathology following damage of the central nervous system (CNS) by an external force. In the CNS, glial scar formation often occurs following TBI, and astrocytes are widely believed to contribute to this scar formation. While the role of astrocytes in extracellular matrix (ECM) production is known, the exact mechanism(s) for this event remain unclear. One possible method is the activation of transient receptor potential vanilloid 4 (TRPV4). TRPV4 is a channel protein found in the astrocyte membrane which has been shown to generate intracellular calcium ions following mechanical stimulation. Previous research …

Scaffold And Tissue Based Therapies To Improve Skeletal Muscle Regeneration After Volumetric Muscle Loss, Benjamin Kasukonis

Graduate Theses and Dissertations

Volumetric muscle loss (VML) is an injury to skeletal muscle characterized by a loss of more than 20% of a muscles volume. The combination of the bulk loss of tissue, transection and separation of myofibers proximal and distal to the injury, loss of innervation and blood supply, and the depletion of muscle progenitor cells results in permanent fibrosis and functional deficits due to loss of contractile tissue. Scaffolds, cells, and engineered constructs have been explored as potential therapeutic interventions to induce myogenesis at the site of a VML injury in animal models, in addition to limited clinical trials. This dissertation …

Isolation Of Metallic Single-Walled Carbon Nanotubes For Electrically Conductive Tissue Engineering Scaffolds, Jakob Hockman

Biomedical Engineering Undergraduate Honors Theses

Metallic single-walled carbon nanotubes (m-SWNTs) were separated from pristine SWNTs using affinity chromatography for use in electrically conductive tissue engineering scaffolds. Approximately one third of SWNTs have metallic properties. Separations were achieved using a protocol modified from Liu & coworkers (2011) in order to improve the method for cell culture environments. Samples enriched in m-SWNTs were isolated and characterized. However, challenges still remain for the complete separation of m-SWNTs from their semiconducting counterpart (s-SWNTs) using this protocol. Approaches to improve separation and reduce the difficulties associated with processing the nanotubes were suggested. One of the ultimate destinations of these nanotubes …

Exploring Biomarkers For Point Of Care Bladder Cancer Detection, Cassandra M. Walker

Biomedical Engineering Undergraduate Honors Theses

Bladder cancer is the 5th most common non-cutaneous human cancer in the United States. While effective methods of detecting bladder cancer are currently practiced, they are often expensive and invasive. There is a need for a noninvasive detection method that can be used in areas with few medical resources. Cell free DNA in urine is normally present only in very low concentrations. Abnormally high levels of cell free DNA in urine could be indicative of disease. This study tests the hypothesis that DNA present in urine can be used as a biomarker for bladder cancer before hematuria is seen in …

Polyethylene Oxide Nanofiber Production By Electrospinning, H. E. Schneider, J. G. Steuber, W. Du, M. Mortazavi, D. W. Bullock

Journal of the Arkansas Academy of Science

Electrospinning is an inexpensive technique that is used to produce nanofibers for a variety of applications. In electrospinning, a polymer solution is dispensed from a hypodermic-like syringe where an intense electric field attracts the solution to a collector while drawing the polymer into a very thin fiber. The diameter of the fiber can be controlled by tuning the process parameters such as the applied electric field, solution flow rate, distance between syringe tip and collector, and the collector geometry. In this paper we describe results from electrospinning poly(ethylene oxide) (PEO), a likely candidate for applications involving scaffolding for tissue engineering. …

Modulation Of Valve Interstitial Cell Function Through Cell Shape And Phenotype, Atefeh Razavi

Graduate Theses and Dissertations

The aortic valve is a highly dynamic structure responding to actively to the chemical, mechanical and physical cues of the valve microenvironment. Valve interstitial cells are dispersed throughout the valve tissue and play an important role in maintaining the integrity and optimum function of the valve. They are a heterogeneous population composed of various phenotype. These phenotypes have specific functions characteristic of valve physiological and pathological conditions. The effect of mechanical loading and chemical modulators on the behavior of the valve interstitial cells have largely been studied. However the role of valve interstitial cell shape as an intrinsic physical cue …

Capillary Electrophoresis For Analysis Of Aβ1-42 Adsorption And Photo-Crosslinking, Jennifer Lynn Kurtz

Graduate Theses and Dissertations

The accumulation of amyloid-beta (Aβ) oligomers is believed to be the driving force behind Alzheimer’s disease (AD) pathogenesis. Due to the metastable nature of Aβ oligomers, the knowledge of Aβ aggregation and accumulation is not well understood. Here, we use capillary electrophoresis (CE) and photo-induced crosslinking of unmodified proteins (PICUP) to learn about the aggregation of Aβ.

First, we explore the effect of capillary coating on Aβ1-42 protein loss using CE. The dynamic coatings tested were PHEA and 50 kDa, 2000 kDa, 5000 kDa, and 8000 kDa PEO. The covalent coating tested was PVA. The results indicated that 2000 kDa …

Characterization Of Human Muscle Extracellular Matrix, Lauren Klaire Wilson

Graduate Theses and Dissertations

The performance of extracellular matrix (ECM) biological scaffolds for the treatment of volumetric muscle loss (VML) has shown promising results with regenerating native muscle in animal models and human patients. However, the limitations of these scaffolds include non-specific characteristics based on the original parameters of the muscle that is lost and this is why our group chose to characterize human skeletal ECM. By understanding the characteristics of the native human skeletal ECM, more desired queues for the biological scaffolds being used to treat VML can be provided. Upper limb and lower limb skeletal muscles were commercially obtained, decellularized using common …

Multiplexed Loop-Mediated Isothermal Amplification Of The 16s Rrna Gene For The Diagnosis Of Neonatal Sepsis In Resource-Limited Environments, Griffin T. Sonaty

Inquiry: The University of Arkansas Undergraduate Research Journal

Sepsis, or dysregulated inflammation caused by bacterial infection, places a disproportionately high burden on newborns in developing countries. This is due in part to a lack of diagnostic tools suitable for sustainable use in resource-limited nurseries. One potential vehicle for a new diagnostic assay is loop-mediated isothermal amplification (LAMP), a high-yield DNA amplification method. LAMP has previously been used to detect genes from single species of bacteria in blood serum samples to aid in sepsis diagnosis. LAMP could be adapted to detect a broad set of bacteria, while retaining a degree of specificity that allows clinicians to begin directed antimicrobial …

Development And Characterization Of An Autologous Whole Cell Breast Cancer Vaccine, Samantha Leigh Kurtz

Graduate Theses and Dissertations

Approximately 40,000 women will die from breast cancer in the United States in 2014. About 90% of these deaths will be due to metastases, rather than the primary tumor and majority of metastases are due to the recurrence and progression of non-metastatic disease. Current adjuvant treatments, such as chemotherapy and radiation, have severe side effects and may result in overtreatment and drug resistance.

Since greater than 90% of patients are diagnosed between stages I-III and have minimal residual disease after treatment, there is an opportunity to treat patients with an autologous breast cancer vaccine. Autologous vaccines under development have a …

A Novel Cell Based Assay For Mmp Inhibitor Screening, Pantrika Krisanarungson

Graduate Theses and Dissertations

Up to date, a plethora of protein based materials are used as implants to stimulate tissue regeneration or fillers to alleviate tissue or organ impairment. This includes glottal insufficiency, urinary bladder incontinence and especially in cosmetic industrial to improve facial contour. Once in vivo, protein-based materials are decomposed by cell secreted matrix metalloproteinases (MMP) and lose their volume within months. By introducing MMP inhibitor (MMPI), the extent of material degradation over time may be reduced. In this dissertation, the development of cell-based assay capable of identifying MMPI candidates for protein-based implant lifetime prolongation is described. To visualize the degradation, DQ-gelatin, …

Construction Of 3d Biomimetic Tissue Niches For Directing Pancreatic Lineage Differentiation Of Human Embryonic Stem Cells, Weiwei Wang

Graduate Theses and Dissertations

The potential of human embryonic stem cells (hESCs) to differentiate into insulin producing beta cells offers great hope for cell-based therapy for diabetes treatment. However, in vitro pancreatic differentiation of hESCs remains challenging. In the past decade, most protocols for differentiating pancreatic cells have been focused on the use of signaling molecule cocktails on 2D substrates. Studies on embryonic development biology strongly suggest that extracellular matrix (ECM) plays a critical role on hESCs behavior. In this work, we first established a 3D collagen scaffold culture system for hESCs differentiating into definitive endoderm (DE), which is the first and most important …

Improvements In Microdialysis Sampling Extraction Efficiency Using Recycled Flow, Justin Cole Deaton

Graduate Theses and Dissertations

Incomplete recovery during microdialysis sampling is hindering important research in neurology, proteomics, and immunology. Although the current generalized solution, decreasing volumetric flow rates (Q), has been and will remain to be a useful strategy it has reached it's a physical limitation due to evaporation at the collection site. Consequently, many important signaling molecules, such as signaling proteins, remain difficult to study. It is more fundamental to consider relative recovery as a function of the interaction time between the perfusate and the environment surrounding the probe.

In this work an increase in relative recovery was predicted by a mathematical model. Using …

Electrospun Polycaprolactone Nanofiber Scaffolds For Tissue Engineering, Andreas Haukas

Graduate Theses and Dissertations

Stem cell and tissue engineering offer us with a unique opportunity to research and develop new therapies for treating various diseases that are otherwise incurable using traditional medicines. However, development of these new therapies replies upon the establishment of in vitro cell culture and differentiation systems that mimic in vivo microenvironments required for cell-cell and cell-ECM interaction. The development of these cell culture systems depends upon the identification of appropriate biomaterials and cell sources. Biomaterials should be carefully selected and fabricated into scaffolds for supporting cell growth and differentiation. In this study, we explored the fabrication of 3D electrospun nanofiber …

Development Of A Microfluidic Device Coupled To Microdialysis Sampling For The Pre-Concentration Of Cytokines, Randy Francisco Espinal Cabrera

Graduate Theses and Dissertations

A proof-of-concept microfluidic device combined with heparin-immobilized magnetic beads was created to concentrate cytokine proteins collected from microdialysis samples. Cytokines are known to be related to several diseases such as cancer, and Parkinson's diseases, so to be able to develop more effective diseases treatments their interactions have to be well understood. Amine-functionalized polystyrene and carboxyl-functionalized magnetic microspheres of ~6.0 ìm in diameter were used to immobilize heparin. The amount of heparin immobilized on polystyrene beads was 5.82 x 10-8 ± 0.36 x 10-8 M per 1.0 x 106 beads and for magnetic beads was 0.64 x 10-8 ± 0.01 x …