Biomedical Engineering and Bioengineering Commons^™

Brown Adipogenesis Of Mouse Embryonic Stem Cells In Alginate Microstrands, Andrea Mannarino Unser

Legacy Theses & Dissertations (2009 - 2024)

The ability of brown adipocytes (fat cells) to dissipate energy as heat shows great promise for the treatment of obesity and other metabolic disorders. Employing pluripotent stem cells, with an emphasis on directed differentiation, may overcome many issues currently associated with primary fat cell cultures. However, brown adipocytes are difficult to transplant in vivo due to the instability of fat, in terms of necrosis and neovascularization, once injected. Thus, 3D cell culture systems that have the potential to mimic adipogenic microenvironments are needed, not only to advance brown fat implantation, but also to better understand the role of brown adipocytes …

Comparison Of Glucose, Fructose And Sucrose Amperometric And Thermal Sensors For Detection Of Carbohydrates In Living Plant Tissue, Scott Mcadoo

Legacy Theses & Dissertations (2009 - 2024)

Ecologists currently cannot test concentrations of carbohydrates in sap in vivo. Testing carbohydrates with current technology would require destructive tissue sampling. The tissue sampling involves large amounts of time and money to collect and test. Aphids are an insect that can bypass a tree’s passive immune system and feed off a phloem region for weeks. A series of enzymatic biosensors could be used to detect the concentration changes of specific carbohydrates. A calcium chelant can be added to defeat a tree’s immune system like an aphid. The detection of three carbohydrates, fructose, glucose and sucrose are involved in this study. …

3d-Bioengineering Of The Conventional Outflow Tract For High Throughput Drug Or Gene Transfer Screening For Glaucoma Treatment, Cula Nolise Dautriche

Legacy Theses & Dissertations (2009 - 2024)

Among ocular pathologies, glaucoma remains the second leading cause of blindness. The molecular mechanisms that lead to glaucoma have been attributed to damage of the conventional outflow tract. Conventional outflow tissues, a composite of the trabecular meshwork and the Schlemm's canal, regulate and maintain homeostatic responses of aqueous humor outflow. In glaucoma, drainage of aqueous humor into the Schlemm's canal is hindered, leading to an increase in intraocular pressure (IOP). That increase in IOP is directly correlated with retinal ganglion cell death, eliminating the relay of visual information to the thalamus and visual cortex, leading to blindness. Although disturbance in …

Bioengineering In Vitro Human Trabecular Meshwork Models For Glaucoma Therapeutic Screening, Karen Yud Torrejon

Legacy Theses & Dissertations (2009 - 2024)

Glaucoma refers to a group of slowly progressing eye disorders that lead to damage to the optic nerve, resulting in irreversible vision loss. Recent statistics by the World Health Organization places glaucoma as a leading cause of blindness worldwide, affecting nearly 80 million people. Lowering intraocular pressure (IOP) is currently the only effective target for therapeutic intervention in glaucoma. IOP is mostly controlled by the outflow of the aqueous humor (AH) through the trabecular meshwork (TM). The TM and adjacent endothelium of Schlemm’s canal, known as the conventional outflow-tract, control AH outflow and thus determine IOP.

Systematic Study Of The Biological Effects Of Nitric Oxide (No) Using Innovative No Measurement And Delivery Systems, Weilue He

Dissertations, Master's Theses and Master's Reports

Nitric oxide (NO) is recognized as the most important small signaling molecule in the human body. An imbalance of NO is closely associated with many serious diseases such as neurological disorders, cardiovascular diseases, chronic inflammations and cancers. Herein two chemiluminescence-based devices (a real-time NO measurement device and a controllable NO delivery device) were developed to facilitate the NO quantitative study and obtain information for NO related drug design.

The first device used for real-time measuring NO(g) flux from living cells was developed and validated. The principle was to use a two-chamber design, with a cell culture chamber and a gaseous …

Engineering Approaches For Suppressing Deleterious Host Responses To Medical Implants, Connor Mccarthy

Dissertations, Master's Theses and Master's Reports

Small diameter (< 6 mm) vascular grafts suffer from serious deleterious effects not encountered with their larger diameter relatives, leading to premature graft failure through restenosis. Platelet activation, inflammation, and smooth muscle cell proliferation are leading contributors to thrombosis and neointimal hyperplasia, both contributors to the progression of restenosis. It may be possible to suppress negative biological responses to vascular implants through the modification of surface properties and incorporation of drug release into blood contacting materials. In this work, bioengineering approaches are presented to improve the biocompatibility of small diameter vascular grafts.

We demonstrate a novel engineering approach for incorporating natural, decollagenized elastin matrices into PEU 1074A reinforced vascular grafts through spray-coating and electrospinning processes in a manner that retains elastin’s excellent blood contacting properties. A vascular construct with excellent mechanical and surgical handling properties demonstrating the suppression of neointimal hyperplasia is presented after 21 days in vivo.

Nitric oxide (NO) has been investigated over the past several decades due to its platelet, inflammation, and smooth muscle cell suppressing effects; and if appropriately delivered, could positively mediate the contributors to restenosis. Here, we characterize a novel macrocyclic NO …

Programmable Dna Delivery To Cells Using Bioreducible Layer-By-Layer (Lbl) Polyelectrolyte Thin Films, Maria Muniz

Wayne State University Theses

Bioreducible, layer-by-layer (LbL) polyelectrolyte films show great promise for use in biomedical implant and gene-delivery applications. These nanometer-scale thin films can easily be coated onto a variety of implantable surfaces or devices. To achieve proof of concept, HEK-293, NIH/3T3, RAW, and MC3T3 cells were transfected using plasmid DNA with the green fluorescent protein reporter gene (GFP-DNA). In order to optimize transfection, a number of polyelectrolytes and biological components were systematically incorporated into the two similar basic LbL structures. Based on our previous degradation assays, it is shown that cellular interactions in vitro can break down the layers of the thin …

Assessment Of Temporal And Spatial Alterations In Spinal Glial Reactivityand The Extent Of Cervical Spinal Axonal Injury In The Rat After Blast Overpressure, Heena S. Purkait

Wayne State University Theses

Blast induced neurotrauma (BINT) is the signature wound of veterans returning from various military operations. A substantial percentage of Operations Enduring Freedom (OEF) and Iraqi Freedom (OIF) veterans have reported to experience ongoing or new pain following their military service. Head (58%) and back (55%) have been the high prevailing locations of pain in these returning OIF and OEF veterans and the underlying pathomechanism of these conditions is yet to be understood. In the context of blast overpressure induced pathological changes, the fundamental question that still needs to be addressed is whether there are any underlying cellular injury changes the …

Using The Symmetry Of False Matches To Solve The Correspondence Problem, Cherlyn J. Ng, Bart Farell

Biomedical and Chemical Engineering - All Scholarship

Veridical stereoscopic depth depends on matching corresponding image points. This requires solving the stereo correspondence problem: how are true matches distinguished from false ones? Conventional algorithms select true matches on the basis of feature detection [what do you mean by ‘feature detection’ here? Is there some more specific term?] and adherence to natural statistics. They reject false matches as noise. We propose here an alternative that uses the signals present in false matches to delineate the true solution. When visualized in a Keplerian array, binocular matches are symmetrically reflected about an axis that is a potential solution. Properties such as …

Diffuse Optical Measurements Of Head And Neck Tumor Hemodynamics For Early Prediction Of Chemo-Radiation Therapy Outcomes, Lixin Dong

Theses and Dissertations--Biomedical Engineering

Chemo-radiation therapy is a principal modality for the treatment of head and neck cancers, and its efficacy depends on the interaction of tumor oxygen with free radicals. In this study, we adopted a novel hybrid diffuse optical instrument combining a commercial frequency-domain tissue oximeter (Imagent) and a custom-made diffuse correlation spectroscopy (DCS) flowmeter, which allowed for simultaneous measurements of tumor blood flow and blood oxygenation. Using this hybrid instrument we continually measured tumor hemodynamic responses to chemo-radiation therapy over the treatment period of 7 weeks. We also explored monitoring dynamic tumor hemodynamic changes during radiation delivery. Blood flow data analysis …

The Effect Of Cholesterol On The Osteoblast Responsiveness To Hydrodynamic Pressure Stimulation, Kristen Lough

Theses and Dissertations--Biomedical Engineering

Hypercholesterolemia is a risk factor for osteoporosis but the underlying mechanism is unknown. Previous evidence suggests that osteoporosis results from an impaired regulation of osteoblasts by fluid pressure fluctuations in the bone matrix. Recently, our laboratory showed that enhanced cholesterol in the cell membrane, due to hypercholesterolemia, alters leukocyte mechanosensitivity. We predict a similar link between osteoblasts and hypercholesterolemia leading to osteoporosis. Specifically, we hypothesize that extracellular cholesterol modifies the osteoblast sensitivity to pressure. MC3T3-E1 cells were exposed to hydrodynamic pressures regimes (mean=40mmHg, amplitude=0-20mmHg, frequency=1Hz) for 1-12 hours. To assess the impact of membrane cholesterol enrichment, cells were pre-treated with …

Human Cardiovascular Responses To Simulated Partial Gravity And A Short Hypergravity Exposure, Qingguang Zhang

Theses and Dissertations--Biomedical Engineering

Orthostatic intolerance (OI), i.e., the inability to maintain stable arterial pressure during upright posture, is a major problem for astronauts after spaceflight. Therefore, one important goal of spaceflight-related research is the development of countermeasures to prevent post flight OI. Given the rarity and expense of spaceflight, countermeasure development requires ground-based simulations of partial gravity to induce appropriate orthostatic effects on the human body, and to test the efficacy of potential countermeasures.

To test the efficacy of upright lower body positive pressure (LBPP) as a model for simulating cardiovascular responses to lunar and Martian gravities on Earth, cardiovascular responses to upright …

Long Term Blood Oxygenation Membranes, Joseph V. Alexander

Theses and Dissertations--Biomedical Engineering

Hollow fiber membranes are widely used in blood oxygenators to remove carbon dioxide and add oxygen during cardiopulmonary bypass operations. These devices are now widely used off-label by physicians to perform extracorporeal blood oxygenation for patients with lung failure. Unfortunately, the hollow fiber membranes used in these devices fail prematurely due to blood plasma leakage and gas emboli formation.

This project formed ultrathin (~100nm) polymer coatings on polymer hollow fiber membranes. The coatings were intended to “block” existing pores on the exterior surfaces while permitting high gas fluxes. This coating is synthesized using surface imitated control radical polymerization.

The coating …

Body Armor Induced Changes In The Trunk Mechancial And Neuromuscular Behavior, Rebecca Leigh Tromp

Theses and Dissertations--Biomedical Engineering

While military body armor is used among warfighters for protection on and off the battlefield, it has been suggested to impede performance and act as a risk factor for the development of musculoskeletal disorders, especially low back pain. Apart from personal suffering, low back pain in soldiers is a great economic burden on the US economy. The objective of this study was to quantify the changes in trunk mechanical and neuromuscular behavior following prolonged exposure to body armor compared to exposure without. A crossover study design was used where 12 sex-balanced participants completed a series of tests before and after …

Inhalable Nanocomposites And Anticancer Agents For Cancer Therapy, Nathanael A. Stocke

Theses and Dissertations--Chemical and Materials Engineering

Cancer is designated as the leading cause of mortality worldwide and lung cancer is responsible for nearly 30% of all cancer related deaths. Over the last few decades mortality rates have only marginally increased and rates of recurrence remain high. These factors, among others, suggest the need for more innovative treatment modalities in lung cancer therapy. Targeted pulmonary delivery is well established for treating pulmonary diseases such as asthma and provides a promising platform for lung cancer therapy. Increasing local deposition of anticancer agents (ACAs) and reducing systemic exposure of these toxic moieties could lead to better therapeutic outcomes and …

Investigation Of Phanerochaete Chrysosporium And Clostridium Thermocellum For Improved Saccharification Of Lignocellulose Under Nonsterile Conditions, William E. Simon

Theses and Dissertations--Biosystems and Agricultural Engineering

Current research efforts are directed at developing competitive processes that can utilize lignocellulose as a feedstock for biorefineries. The purpose of this study was to investigate methods of processing lignocellulosic material so that its monosacharides can be more easily accessed for fermentation, the lack of which is hindering the economics and widescale adoption of lignocellulosic biorefining. The monosaccharides are of interest because they can be used by Clostridium beijerinckii downstream of P. chrysosporium and C. thermocellum in a sequential bioprocess to produce butanol. Butanol is an attractive biofuel because it can be utilized without modifying current transportation infrastructure. Butanol is …

Up Regulation Of Heat Shock Protein 70b (Hsp70b) And Ssa1 In Chlamydomonas Reinhardtii Via Hsp70a-Rbcs2 And Psad Promoter, B. Kirtley Amos

Theses and Dissertations--Biosystems and Agricultural Engineering

Fabrication of effective algae cultivation systems adjacent to coal-fired power plants to fixate waste CO₂ would represent a sizable step towards achieving a carbon neutral energy cycle. However, emission gas would elevate the algal cultivation system temperature and decreases its pH without expensive preprocessing. Increased temperature and acidity constitutes a profound stress on the algae. Although stressed algae produce heat shock proteins (HSPs) that promote protein folding and protect against stress, the ordinary biological response is insufficient to protect against coal flue gas. Experimental upregulation of HSPs could make algae respond to the stress caused by high temperatures and …

Target-Directed Biosynthetic Evolution: Redirecting Plant Evolution To Genomically Optimize A Plant’S Pharmacological Profile, Dustin Paul Brown

Theses and Dissertations--Neuroscience

The dissertation describes a novel method for plant drug discovery based on mutation and selection of plant cells. Despite the industry focus on chemical synthesis, plants remain a source of potent and complex bioactive metabolites. Many of these have evolved as defensive compounds targeted on key proteins in the CNS of herbivorous insects, for example the insect dopamine transporter (DAT). Because of homology with the human DAT protein some of these metabolites have high abuse potential, but others may be valuable in treating drug dependence. This dissertation redirects the evolution of a native Lobelia species toward metabolites with greater activity …

Computational Modeling Of Cardiac Biomechanics, Amir Nikou

Theses and Dissertations--Mechanical and Aerospace Engineering

The goal of this dissertation was to develop a realistic and patient-specific computational model of the heart that ultimately would help medical scientists to better diagnose and treat heart diseases. In order to achieve this goal, a three dimensional finite element model of the heart was created using magnetic resonance images of the beating pig heart. This model was loaded by the pressure of blood inside the left ventricle which was measured by synchronous catheterization. A recently developed structurally based constitutive model of the myocardium was incorporated in the finite element solver to model passive left ventricular myocardium. Additionally, an …

Morphology Of Brain Sulci Trabeculae And Its Effect On Brain During Impacts, Sharlin Anwar

Dissertations and Theses

Traumatic brain injury (TBI) is an intracranial injury caused by direct contact or non-contact head impacts to the brain. TBI is a major problem that accounts for high incidents of hospitalizations each year. Thus, it is important to understand and predict the occurrence of TBI in an impact. It has been shown that the subarachnoid space (SAS) trabeculae play an important role in damping the effect of an impact, thus reducing the injuries. However, the influence of sulci parameters and the sulci trabeculae in TBI due to impact is unexplored. Studies have shown that inclusion of sulci in brain models …