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Full-Text Articles in Engineering

Acceleration Of The Maturation Of Tissue Engineered Grafts By Dynamic Force Stimulation Or Gene Therapy, Shila Taylor Dec 2007

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

All Theses

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 Dec 2007

Optical Force Based Cancer Cell Identification, Justin Roman

All Theses

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 Dec 2007

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

All Dissertations

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 Dec 2007

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

All Theses

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 Dec 2007

Glycosaminoglycan Stabilization In Bovine Pericardium, Lauren Browne

All Theses

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 Aug 2007

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

All Theses

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 Aug 2007

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

All Theses

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 …


Activation Of Systemic Adhesion Molecules And C Reactive Protein In Response To Biomaterial Particle Induced Cytokine Production, Robin Graham Aug 2007

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

All Dissertations

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 …


In Situ Photopolymerized Hydrogels For Enhancing Protein Delivery, Chien-Chi Lin Aug 2007

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

All Dissertations

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 …


Non-Boltzamann Sampling For The Accurate Calculation Of Peptide-Surface Adsorption Free Energy, Feng Wang Aug 2007

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

All Dissertations

%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 …


Differentiation Modulation Of Adult Stem Cells In An Adipose System, Aditya Chaubey Aug 2007

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

All Dissertations

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 …


The Differential Effects Of Two Critical Osteoclastogenesis Stimulating Factors On Bone Biomechanics, Yuyu Yuan May 2007

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

All Dissertations

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. …


Spatial Sensors For Quantitative Assessment Of Retrieved Arthroplasty Bearings, Melinda Harman May 2007

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

All Dissertations

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 …


Viability, Functionality, And Genetic Assessment Of Cells After Laser Guidance, Tabitha Rosenbalm May 2007

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

All Theses

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 …


Dynamic Measurements Of Lubrication Film Thickness Of Uhmwpe Contacts For Total Joint Replacements, Andrew Clark May 2007

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

All Dissertations

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 …


Effects Of Ionizing Radiaton On Diaphyseal Cortical Bone, Neil Travis May 2007

Effects Of Ionizing Radiaton On Diaphyseal Cortical Bone, Neil Travis

All Theses

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 …