Biomedical Engineering and Bioengineering Commons^™

Assessment Of Fifth Metatarsal Etiology, Daniel Reed

All Theses

The fifth metatarsal 'Jones Fracture' is a fracture that occurs 3.5cm distal to the tuberosity. It is an injury that is common in athletes, especially those who participate in sports with a lot of lateral movement. The Jones Fracture is known for its difficulty to heal due to non-union and re-fracture. There has been much research recently regarding in-shoe pressure distributions and their relation to shoe type, movement, and shoe surface interaction. However, only the forces along the bottom of the foot have been investigated. Literature and the direction of fracture seem to implicate a force on the lateral portion …

Risedronate Prevents Early Bone Loss Resulting From Whole-Body Irradiation, Eric Livingston

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Osteoporosis is a condition characterized by a reduction in bone strength resulting in an overall increase in the risk of fracture. There are many factors that contribute to the development of this condition, including ionizing radiation exposure. Declines in bone volume and trabecular micro-architecture have been found following exposure to multiple types of radiation. Past research has implicated reduction of osteoblast function and changes to vasculature as the primary sources of bone deterioration. Recently, an early increase in osteoclast number was observed following exposure to low-energy X-rays, identifying an increase in resorption as a possible cause and potential target for …

Biomechanical Evaluation Of Two Methods Of Humeral Shaft Fixation, Joshua Catanzarite

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Biomechanical evaluations of fracture fixation devices attempt to determine implant performance by approximating the in vivo conditions. This performance is affected by many factors and relies on the complex bone-implant interface. Biomechanical tests can be designed in a variety of ways in order to evaluate device performance with respect to any number of these bone-implant interactions. Standardized tests, designed by groups such as the American Society for Testing and Materials (ASTM), are often designed either to determine the performance of a specific type of fixation device or for direct comparison between different devices. Additionally, many biomechanical evaluations are designed for …

Quantifying Antalgic Gait Knee Function Using Inertial Sensor Technology, William Mostertz

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The use of body-fixed inertial sensors to analyze human movement may prove useful in the medical field. Improving orthopaedic device design, diagnosing musculoskeletal disorders, and rehabilitation assessment could all benefit from a mobile gait analysis system based on inertial sensors. More specifically, patients recovering from lower limb corrective surgeries tend to adjust gait patterns to accommodate pain, a condition referred to as antalgic gait. Currently there is no quantitative method available to assess recovery for this patient population during post-operative management. A comparison of the inertial sensor system with the camera-based industry standard has confirmed it as a viable method …

Radiation-Induced Osteoporosis: Bone Quantity, Architecture, And Increased Resorption Following Exposure To Ionizing Radiation, Jeffrey Willey

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Skeletal complications from radiation therapy have been described for breast, brain, pelvic, and blood cancers. These problems include atrophy, fractures, and osteoradionecrosis. Improved survivorship rates of cancer patients receiving radiotherapy increases the importance of understanding the causal mechanisms and long-term effects of radiation-induced bone loss. One such long-term effect is bone fractures following radiation therapy for cancer treatment. The incidence of hip fractures is significantly increased following targeted radiotherapy for cancer. This decline in bone health can have a severe impact on the patient's functional capabilities. This damage to bone following irradiation is thought to involve damage to both osteoblasts …

Study Of Electrospinning Of Property-Modulated Biomedical Microfibers, Scott Taylor

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Electrospinning technologies have been of great interest in recent years, due in large part to developments in the field of Bioengineering, including the preparation of novel polymers and advances in tissue engineering, specifically for therapeutic applications. The electrospinning process is, in general, a very benign process that allows the preparation, under mild conditions, of micro- and nano-scale fibers from fiberforming materials, as well as traditionally non-fiber forming materials. This process is of specific interest to the biomedical community because it affords an opportunity to create highly-tailored novel constructs with a multitude of possible uses. Some proposed uses for these materials …

Acceleration Of The Maturation Of Tissue Engineered Grafts By Dynamic Force Stimulation Or Gene Therapy, Shila Taylor

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Over 16 million people suffer from osteoarthritis (OA). As the body ages OA and other cartilage diseases create an imbalance of anabolic and catabolic cell activities in cartilage and or over time the cartilage is damaged and wears away which creates lesion that resulting in pain. Most clinical surgeries are either temporary or have not gone through trials to test their success. For a long term solution researchers have been looking at replacing cartilage with a tissue engineered graft. One of the major problems to date has been is the strength of the scaffold.
Natural cartilage needs loading for its …

Optical Force Based Cancer Cell Identification, Justin Roman

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We present the basis of a novel, non-invasive technique for cell diagnostics which utilizes the optical force generated by a weakly focused laser beam to distinguish cells based on their size, structure, composition, and membrane properties. Cell populations of different types, biological states or with different treatments can be studied. This research focuses on two particular instances where other methods of cell sorting, such as those that require fluorescent markers, are not ideal. What's more, this research emphasizes the ability to sort morphologically similar cells that are identical to the naked eye, but phenotypically different on the molecular level. The …

Development Of An In Vitro Test System For Breast Cancer Research, Chih-Chao Yang

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In the United States, breast cancer is the third most common cause of cancer death (after lung cancer and colon cancer). In 2007, breast cancer is expected to cause 40,910 deaths (7% of cancer deaths; almost 2% of all deaths) in the U.S. The long term goal of this project is to develop an in vitro test system that can be used to develop breast cancer vaccine or screen breast cancer chemotherapy. This dissertation was driven by four objectives and it can be thought as a toolbox that provides practical experimental design and lab work for the development of an …

Adipocyte Response To Injectable Beads Engineered For Breast Tissue Reconstruction, Katherine Neser

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It is estimated that over 150,000 patients will be diagnosed with invasive breast cancer in 2007. Patients must undergo a mastectomy or a lumpectomy to remove the cancerous tissue, but only a mastectomy allows breast reconstructive surgery. Due to the limitations of current reconstruction options, new alternatives are being explored. Injectable materials have been suggested for breast tissue reconstruction because of their versatility. Cells cultured on injectable beads form cell carriers that may be mixed with a hydrogel, resulting in a construct that may be injected through a syringe to restore normal tissue mass. This solution offers breast cancer patients …

Glycosaminoglycan Stabilization In Bovine Pericardium, Lauren Browne

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Glutaraldehyde crosslinked bovine pericardium has been used for fabrication of bioprosthetic heart valves as well as cardiac patches for soft tissue repair. However, calcification and limited mechanical stability result in shortened life for the prostheses. Previous research has shown that glutaraldehyde crosslinking does not stabilize glycosaminoglycans (GAGs) and that GAGs are lost from porcine bioprosthetic heart valves[1]. Bovine pericardial tissue is composed of an amorphous network of collagen and elastin fibers, proteoglycans, and GAGs. The GAGs of bovine pericardium include dermatan sulfate, chondroitin sulfate, and hyaluronan [2].
It is hypothesized that Glut does not stabilize GAGs in pericardium and loss …

Glycosaminoglycan Stabilization Reduces Tissue Buckling In Bioprosthetic Heart Valves, Sagar Shah

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Currently, bioprosthetic heart valves are crosslinked with glutaraldehyde to prevent tissue degradation and to reduce tissue antigenicity. Glutaraldehyde forms stable crosslinks with collagen via a Schiff base reaction of the aldehyde with an amine group of the hydroxylysine/lysine in collagen. However, within a decade of implantation, 20-30% of these bioprostheses will become dysfunctional and over 50% will fail due to degeneration within 12-15 years post-operatively.
Gylcosaminoglycans, a major constituent of valvular tissue, play an important role in maintaining a hydrated environment necessary for absorbing compressive loads, modulating shear stresses, and resisting tissue buckling. One of the disadvantages of glutaraldehyde crosslinking …

An In Vitro Evaluation Of Dbm As A Tissue Engineered Scaffold, Stephanie Arnold

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Over 500,000 bone graft procedures are performed each year in the United States. Bone grafting involves a surgical procedure to replace missing bone. Problems can arise with donor and defect sites during and after surgery, sometimes resulting in poor clinical results. The development and optimization of bone graft substitutes via a tissue engineering approach could markedly improve bone graft surgical outcome. Demineralized bone matrix (DBM), a bone graft material, is currently used in a clinical setting but has variable success rates.
The primary objective of the research presented in this thesis was to assess the cellular activity of D1 mouse …

Non-Boltzamann Sampling For The Accurate Calculation Of Peptide-Surface Adsorption Free Energy, Feng Wang

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%Abstract
The objectives of this project are 1) the setup and refinement of peptide-SAM surface model systems with explicit water using CHARMM and 2) the development of up-to-date simulation protocols for the accurate calculation of adsorption free energy by incorporating the recent development of non-Boltzmann sampling methods in molecular dynamics and applying it for the calculation of adsorption free energy of short peptides onto well-characterized self-assembled monolayers, which is important for understanding protein/surface interactions.
A software package called the Simulation Template Engine for Peptides at Surfaces (STEPS) was developed for the fulfillment of the first objective. It facilitates the automatic …

In Situ Photopolymerized Hydrogels For Enhancing Protein Delivery, Chien-Chi Lin

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In recent years, there has been immense interest in the utilization of photopolymerized hydrogels as carriers for controlled protein delivery and cell scaffolds for tissue engineering applications. Although poly(ethylene glycol) (PEG)-based hydrogels formed from mild photopolymerization methods have been suggested as biocompatible matrices that allow for safely encapsulating biomolecules including proteins, peptides, DNA, and cells, the adverse effects of photopolymerization reactions on the encapsulated proteins have largely been overlooked. In addition, conventional hydrophilic hydrogels fail to effectively control protein delivery rates due to their high permeability. These two problems are critical since the delivery of protein therapeutics from hydrogel matrices …

Differentiation Modulation Of Adult Stem Cells In An Adipose System, Aditya Chaubey

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The need for soft tissue reconstruction or augmentation has increased continuously over the years. This need is compounded by patients suffering from post-traumatic repair and congenital soft-tissue deformities. All the current options available to treat the soft tissue deformities have inherent difficulties associated with them. Hence, more research is needed to come up with a better solution to this problem which is only going to increase in magnitude. Tissue engineering is a relatively new technique which has the potential to deliver a cell-based device which can overcome the problems associated with traditional therapies. However, before it becomes clinically viable we …

Activation Of Systemic Adhesion Molecules And C Reactive Protein In Response To Biomaterial Particle Induced Cytokine Production, Robin Graham

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Chronic inflammation has been identified as a major contributor to many diseases including, atherosclerosis, osteoporosis, dementia, Alzheimer's disease and type 2 diabetes, to name a few. Many of the same markers of inflammation found in the diseases listed above, including IL-1, IL-6, TNF-α, NF-B and adhesion molecules, have also been found in wear debris induced osteolysis. While the local response to biomaterial wear debris has been characterized quite extensively, very little is known about the systemic effect of biomaterial wear debris on the inflammatory system. The objectives of this study were to evaluate the in vitro and in vivo inflammatory …

The Differential Effects Of Two Critical Osteoclastogenesis Stimulating Factors On Bone Biomechanics, Yuyu Yuan

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Many skeletal diseases, such as osteoporosis and malignant bone metastases, are generally osteolytic and associated with increased bone resorption and decreased bone strength. Within a complex cytokine environment, the proteins RANKL and M-CSF are critical for osteoclast differentiation and activation, and thus fundamental effectors of osteolytic disorders. Previous studies showed that M-CSF stimulates the proliferation and early differentiation of osteoclast progenitors to osteoclast lineage, while RANKL targets the later stages of fusion and activation, and stimulates the formation of functional active osteoclasts. However, impacts of artificially elevated levels of these proteins on the skeleton system have not been fully characterized. …

Viability, Functionality, And Genetic Assessment Of Cells After Laser Guidance, Tabitha Rosenbalm

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We systematically vary the controllable laser parameters, namely, wavelength, intensity, and exposure time of the laser on single cells to clearly establish laser parameters that allow negligible cell damage with significant cellular position control. To accomplish this goal, embryonic day 7 (E7) chick forebrains neurons were cultured with control and test cells selected one hour after seeding to allow attachment, at which time test cells were subjected to the laser. Cells were imaged at 4, 12, 24, and 36 hours after laser exposure to evaluate viability and functionality by using the Live/Dead Viability Cytotoxicity Kit (Molecular Probes L3224) and measuring …

Spatial Sensors For Quantitative Assessment Of Retrieved Arthroplasty Bearings, Melinda Harman

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Evaluation of retrieved joint arthroplasty bearings provides unique evidence related to the physiological environment in which bearing materials are expected to perform. This dissertation describes the development of novel spatial sensors and measurement strategies for standardized, quantitative assessments of arthroplasty bearings, including total knee replacements, unicompartmental knee replacements, and total hip replacements. The approach is to assess bearings that endured a finite duration of function in patients, with particular emphasis on expanding our understanding of the biomechanical conditions specific to bearing function and wear in the physiological environment. Several quantifiable parameters are identified that prove comparable to pre-clinical in vitro …

Effects Of Ionizing Radiaton On Diaphyseal Cortical Bone, Neil Travis

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Radiation exposure is experienced in both radiotherapy and exploratory space missions. As cancer treatments improve and astronauts aim to explore beyond low earth, radiation's effects on bone must be clearly understood. Nine-week old female C57BL/6 mice were evaluated for cortical bone changes by mechanical testing, micro-computed tomography, quantitative histomorphometry, percent mineralization and micro-hardness indentation. Study one, Multi-Type study, mice received a 2 Gray (Gy) gamma, proton, iron and carbon whole body radiation dose and sacrificed 110 days post-exposure. Study two, High-Dose study, mice received a 7 Gy gamma radiation whole body dose and sacrificed 14 days post-exposure. Neither study revealed …

Dynamic Measurements Of Lubrication Film Thickness Of Uhmwpe Contacts For Total Joint Replacements, Andrew Clark

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A new contact sensing technology previously developed in the Biotribology Laboratory at Clemson University was further studied, evaluated, and characterized to extend its use to the measurement of lubricating film thickness. First, the laboratory's force-controlled knee joint simulator was used while dynamic contact pressure measurements under both dry and lubricated conditions were made using the sensor technology employed in two different artificial knee implant geometries. Each implant was machined by the manufacturer from custom blocks of ultra high molecular weight polyethylene (UHMWPE) containing a grid of discrete sensing regions. The difference between the dry and lubricated contact areas measured at …

Elastic Degradable Polyurethanes For Biomedical Applications, Changhong Zhang

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Several series of polyurethanes were synthesized with linear or crosslinked structures by using different synthesis routes. Two studies are mentioned: (1) the synthesis of degradable polyurethanes with linear structure and the investigation of the elasticity and cytophilicity of the materials as function of the chain extender, and (2) the synthesis and the investigation of the biocompatibility, degradation, hydrophilicity and mechanical properties of the polyurethane-based hydrogels with crosslinked structure.

Validation Of An Inertial Sensor System For Quantifying Knee Function, Aaron Koslin

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Gait analysis has become a useful tool for clinicians in evaluating the progression of pathologies through functional analysis. The high cost and dedicated laboratories associated with the traditional camera-based motion analysis systems present the need for an alternative system. Direct measurement of kinetic parameters using inertial sensors (gyroscopes and accelerometers), in place of indirect calculations from position data obtained using cameras, has been shown effective in resolving important gait parameters.
In order to directly compare gait parameters obtained using inertial sensors and a camera system, data was simultaneously collected from both systems for seven test subjects during normal gait. Three …

Tannic Acid Crosslinked Collagens And Potential For Breast Tissue Engineering, Cheryl Parzel

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The purpose of this study was to develop and assess a potential key feature in a minimally-invasive breast reconstruction device and to collect information for an in vitro tissue test system. Tannic acid is a hydrolysable plant tannin, and it has been determined that tannic acid functions as a collagen crosslinking agent through both hydrogen bonding mechanisms and hydrophobic effects. Additionally, current research suggests that tannic acid may have anti-tumor properties. Therefore, it has been proposed that tannic acid can be used as an agent to induce apoptotic processes in any transplanted adult stem cells that are inclined to spontaneously …

Development Of A Cellular Fiber Spinning Technology For Regenerative Medicine, Willie Jones

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In order to prove that our textile hollow fiber spinning apparatus was adequate for cellular encapsulation, we confirmed the viability and metabolic activity of green fluorescent protein (GFP) labeled bovine mammary epithelial cells (MAC-Ts) that were encapsulated in either the wall or lumen of alginate fibers. After a 21 day in vitro macroscopic evaluation, no decrease in fluorescence was observed; and it was determined that MAC-Ts encapsulated under both methods produced lactic acid and consumed glucose. Histomorphological analyses revealed that the diameter of the MAC-Ts increased under both encapsulation scenarios, with little to no evidence of cell cluster propagation. Based …

Tribological Systems For The Evaluation Of Supercritical Carbon Dioxide Sterilized Ultra-High Molecular Weight Polyethylene, John Desjardins

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Polymeric biomaterials are especially susceptible to changes in mechanical and surface material properties as a result of sterilization processes that involve heat, moisture and/or irradiation. This is problematic for polymeric materials used in total joint replacement bearings, as these constructs must retain their superior mechanical and tribological properties over their expected 10-20 years of implantation. A younger more active patient population has now exacerbated this longevity issue with service lifetimes of 20+ years now being expected. Supercritical phase carbon dioxide (SC-CO2) is an industrial solvent that has shown great promise as a sterilizing agent in the food industry. Recently, SC-CO2 …

Stabilization Of Vascular Elastin By Treatment With Tannins, Jason Isenburg

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Elastin is an important component of the extracellular matrix that endows cardiovascular tissue with the ability to extend and recoil repetitively. It has been shown that elastin may be vulnerable to enzymatic degradation and calcification in certain pathological cases. As a result, elastin degeneration may be associated with the failure of tissue-derived cardiovascular devices, such as bioprosthetic heart valves, as well as the development and progression of aortic aneurysms, a disease associated with progressive connective tissue degeneration of the arterial wall. Therefore, an elastin stabilizing agent may be beneficial for both applications. As such, our objectives for elastin stabilization are …

Soccer Headgear Effects On Impact Profiles During A Heading Scenario, Ryan Posey

All Theses

The risk of head injuries in the sport of soccer has recently become a topic of concern, particularly with youth players whom may suffer long-lasting or even permanent effects from a severe head injury. In response to these worries, headguards have been developed specifically for use in soccer. These headguards have been studied using crash test dummy heads mounted with various electronic instruments - accelerometers, gyroscopes, etc. The headgear-mounted dummy heads have been struck with various objects (soccer ball, another dummy head, pole, etc) to test for changes in head acceleration response.
Testing of soccer headgear has previously been limited …

The Synthesis, Characterization, And Cell Seeding Of A Collagen/Hydroxyapatite Porous Scaffold For Treatment Of Osseous Defects, Kim Rachel Patterson

All Theses

The need for finding a bone graft substitute stems from the fact that approximately 200,000 bone grafting procedures are performed annually in the U.S. alone. Although biological grafting options (i.e. autografts & allografts) exist, they do suffer from inherent problems. These include limited resources, costly processing, and potential for pathogen transfer. Thus, investigators have sought synthetic alternatives.

The objective of this research was to utilize hydroxyapatite (HA) and collagen, both analogues to the major constituents of bone, to fabricate an optimal synthetic osteoconductive/osteoinductive bone scaffold. Current attempts by other investigators to combine the two materials have been met with some …