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Articles 121 - 150 of 224

Full-Text Articles in Biomedical Engineering and Bioengineering

Induced Elastic Matrix Synthesis Within 3-Dimensional Collagen Constructs, Lavanya Venkataraman Dec 2012

Induced Elastic Matrix Synthesis Within 3-Dimensional Collagen Constructs, Lavanya Venkataraman

All Dissertations

Elastin, a primary component of elastic arteries, maintains structural stability of the cyclically recoiling artery, and critically regulates vascular cell behavior. Accelerated degradation of elastic matrix, such as that seen in vascular pathologies like abdominal aortic aneurysms (AAA), can therefore severely compromise vessel homeostasis. Tissue engineering and in-situ matrix repair strategies evaluated so far are primarily limited in inducing adult vascular cells to replicate the complex elastic matrix assembly process, and restore lost matrix integrity. Previously, our lab established the elastogenic benefits of concurrent delivery of TGF-β1 and HA-oligomers (together termed elastogenic factors, EFs), within 2D cultures of rat aortic …


Develop Novel Frap Techniques For Determining Anisotropic Solute Diffusion In Cartilaginous Tissues, Changcheng Shi Dec 2012

Develop Novel Frap Techniques For Determining Anisotropic Solute Diffusion In Cartilaginous Tissues, Changcheng Shi

All Dissertations

Cartilaginous tissue is a connective tissue composed of specialized cells (e.g., chondrocytes and fibroblasts) that produce a large amount of extracellular matrix (ECM), which is comprised mostly of collagen fibers, abundant ground substance rich in proteoglycan, and elastic fibers. It is characterized by its avascular structures within the tissue, implying that nutrition for normal tissue cells, for maintaining a healthy ECM, is mainly supplied through diffusion from nearby vascularized tissues and synovial fluid. Poor nutritional supply to the cartilaginous tissue is believed to be an important factor leading to tissue degeneration. Moreover, due to the complex collagen fiber structures, the …


The Effects Of Low Dose Ionizing Radiation Exposure On The Metabolic And Mechanical Properties Of Articular Cartilage, Carl Lindburg Dec 2012

The Effects Of Low Dose Ionizing Radiation Exposure On The Metabolic And Mechanical Properties Of Articular Cartilage, Carl Lindburg

All Theses

Radiation therapy is necessary treatment for many cancer patients due to its non-surgical, yet aggressive and efficacious properties. In fact, over 50% of patients with cancer will undergo some form of radiotherapy during the course of their treatment. While the biological response to ionizing radiation has been examined over the years and many adverse effects have been identified, the effects of radiation on mature cartilage and musculoskeletal tissues are not well understood. Bone, once thought to be a tissue relatively resistant to radiation, has recently been shown to have osteoporosis-like bone atrophy after exposure to low doses (2 Gy) of …


Bioswellable Amphiphilic Copolymers, David Ingram Dec 2012

Bioswellable Amphiphilic Copolymers, David Ingram

All Theses

The suture is one of the most commonly used medical devices, consisting of a fiber, a surgical needle and the packaging in which it is stored. The fiber itself remains after implantation for a defined time and is responsible for the approximation of the wound during the healing process. The needle merely serves to aid in insertion, and preferably has a diameter larger than the diameter of the fiber .
The 1970's marked the birth of a new family of fibrous materials for the approximation of wounds: synthetic absorbable sutures. This family has the ability to provide wound support during …


A Novel Haptic Simulator For Evaluating And Training Salient Force-Based Skills For Laparoscopic Surgery, Ravikiran Singapogu Aug 2012

A Novel Haptic Simulator For Evaluating And Training Salient Force-Based Skills For Laparoscopic Surgery, Ravikiran Singapogu

All Dissertations

Laparoscopic surgery has evolved from an 'alternative' surgical technique to currently being considered as a mainstream surgical technique. However, learning this complex technique holds unique challenges to novice surgeons due to their 'distance' from the surgical site. One of the main challenges in acquiring laparoscopic skills is the acquisition of force-based or haptic skills. The neglect of popular training methods (e.g., the Fundamentals of Laparoscopic Surgery, i.e. FLS, curriculum) in addressing this aspect of skills training has led many medical skills professionals to research new, efficient methods for haptic skills training.
The overarching goal of this research was to demonstrate …


Investigating The Role Of Mechanosensitive Ion Channels In Urothelial Cell Pressure Mechanotransduction, Shawn Olsen Aug 2012

Investigating The Role Of Mechanosensitive Ion Channels In Urothelial Cell Pressure Mechanotransduction, Shawn Olsen

All Dissertations

Overactive bladder (OAB) is a bladder disorder that is characterized by bladder storage symptoms of urgency with or without urge incontinence, frequency, nocturia, and, as of 2003, affected approximately 16.5% of adults in the United States with an annual treatment cost of over $65 billion. While therapies are available to mitigate the symptoms of OAB, there are no treatments for the cause of OAB, due to the lack of understanding of the etiology of the disorder. Recent research has provided evidence that the bladder urothelium is not just a passive barrier, but is also sensitive to various chemical and mechanical …


Effects Of Physiological Dynamic Compression Loading On Gold Nanoparticle Permeation Of Articular Cartilage, Britton Mccaskill Aug 2012

Effects Of Physiological Dynamic Compression Loading On Gold Nanoparticle Permeation Of Articular Cartilage, Britton Mccaskill

All Theses

Articular cartilage is essential part of the human body that aids in support and locomotion. It has unique biochemical and biomechanical properties that allow it to act as a shock absorber to disperse and distribute loading of the joints. However, it has a limited capacity to repair itself because it is not vascularized and must receive its nutrients from the surrounding synovial fluid. Articular cartilage damage can lead to many pathological conditions, including osteoarthritis. Currently, there are many surgical treatment methods that repair some of the damage if it is localized, but for widespread degradation seen in osteoarthritis, there are …


Oral Delivery Of Peptide Drugs For Mitigation Of Crohn's Disease, Paul Blichmann Aug 2012

Oral Delivery Of Peptide Drugs For Mitigation Of Crohn's Disease, Paul Blichmann

All Theses

Protein drugs are typically administered intravenously, but this practice has clear disadvantages such as widespread circulation and swift clearance from the body. Orally delivered protein drugs are not yet available but potentially offer improved distribution, retention, and activity by use of protective matrices and cell-specific targeting. Much work has been done on delayed release formulations for the upper intestine, but there has not been overwhelming evidence of protection of peptides from gastric conditions. In many instances the large intestine may be a better release target due to lower proteolytic activity. Afflictions of the colon such as Inflammatory Bowel Disease and …


The Formulation Of A Bone Targeted Drug Delivery System Of Poly(Glycolic Acid)-Poly(Ethylene Glycol) Coated Hydroxyapatite Nanoparticles For The Delivery Of Statins, Erika Jelen Aug 2012

The Formulation Of A Bone Targeted Drug Delivery System Of Poly(Glycolic Acid)-Poly(Ethylene Glycol) Coated Hydroxyapatite Nanoparticles For The Delivery Of Statins, Erika Jelen

All Theses

Bone is a form of mineralized connective tissue that provides strength and rigidity to the skeleton. The two primary components within bone tissue are an organic extracellular matrix, containing type I collagen, and an inorganic mineral component composed mainly of calcium phosphate hydroxyapatite crystals. Over time the microarchitecture of bone can break down due to a variety of different factors, mainly the onset of osteoporosis in post-menopausal women, Paget's disease, and the experience of a loss of gravity during space flight. Currently there are about ten million people in the United States alone suffering from osteoporosis.
The prevention of further …


Stabilization Of Extracellular Matrix Components In Bioprosthetic Heart Valves Using Neomycin And Pentagalloyl Glucose Enhanced Crosslinking, Daniel Tripi Aug 2012

Stabilization Of Extracellular Matrix Components In Bioprosthetic Heart Valves Using Neomycin And Pentagalloyl Glucose Enhanced Crosslinking, Daniel Tripi

All Theses

Bioprosthetic heart valves (BHVs) fail within 12-15 years of implantation due to limited durability. This limits their application to elderly population. Younger patients with contraindications for long-term anticoagulant therapy necessary for mechanical heart valves may also receive BHVs. Investigation into improving valve durability can lead to longer implant life, increased quality of life for patients receiving BHVs, and a broadened patient demographic.
Current BHVs are chemically treated with glutaraldehyde (GLUT) to stabilize collagen via chemical crosslinking and to reduce tissue antigenicity. GLUT fails to adequately stabilize elastin and glycosaminoglycans (GAGs), essential extracellular matrix components for valve function and durability. Degradation …


Surface Damage In Retrieved Total Knee Replacement Femoral Components, Estefania Alvarez May 2012

Surface Damage In Retrieved Total Knee Replacement Femoral Components, Estefania Alvarez

All Dissertations

The metallic femoral components of total knee replacements are subject to in vivo surface damage and roughening that can severely limit the service lifetime of the bearing system. To date, there are no national standards by which to characterize the severity and damage modes of these critical bearing surfaces, and therefore it remains difficult to accurately assess how femoral damage influences total joint replacement bearing longevity. In vitro and in vivo studies have shown that severe surface damage of the femoral component can occur, however, there is still no defined test methodology that can identify or replicate the types of …


Nanopillar Based Electrochemical Biosensor For Monitoring Microfluidic Based Cell Culture, Rajan Gangadharan May 2012

Nanopillar Based Electrochemical Biosensor For Monitoring Microfluidic Based Cell Culture, Rajan Gangadharan

All Dissertations

In-vitro assays using cultured cells have been widely performed for studying many aspects of cell biology and cell physiology. These assays also form the basis of cell based sensing. Presently, analysis procedures on cell cultures are done using techniques that are not integrated with the cell culture system. This approach makes continuous and real-time in-vitro measurements difficult. It is well known that the availability of continuous online measurements for extended periods of time will help provide a better understanding and will give better insight into cell physiological events.
With this motivation we developed a highly sensitive, selective and stable microfluidic …


Evaluation Of A Bisphosphonate Enriched Ultra-High Molecular Weight Polyethylene For Enhanced Total Joint Replacement Bearing Surface Functionality, Cassandra Wright-Walker May 2012

Evaluation Of A Bisphosphonate Enriched Ultra-High Molecular Weight Polyethylene For Enhanced Total Joint Replacement Bearing Surface Functionality, Cassandra Wright-Walker

All Dissertations

Each year in the United States there is an increasing trend of patients receiving total joint replacement (TJR) procedures. Approximately a half million total knee replacements (TKRs) are performed annually in the United States with increasing prevalence attributed to baby-boomers, obesity, older, and younger patients. This trend is also seen for total hip replacements (THRs) as well. The use of ultra high molecular weight polyethylene (UHMWPE) inserts in TJRs results in wear particle-induced osteolysis, which is the predominant cause for prosthesis failure and revision surgery. Sub-micron size particle generation is inevitable despite the numerous efforts in improving this bearing material. …


Quantitative, Spatial Imaging Based Measurements To Assess Cellular Health And Oxygenation In A Tissue Engineered Test System, Erik Bland May 2012

Quantitative, Spatial Imaging Based Measurements To Assess Cellular Health And Oxygenation In A Tissue Engineered Test System, Erik Bland

All Dissertations

Three-dimensional in vitro tissue test systems are employed to examine cell behavior, test responses to drugs and vaccines, and answer basic biological questions. These systems are more physiologically relevant than two-dimensional cell cultures, and are more relevant, easier and less expensive to maintain than animal models. However, methods used to measure cell behavior and viability have been developed specifically for two-dimensional cell cultures or animal models, and are often not optimally translated to three-dimensional in vitro test systems. The purpose of this work was to aid in the development of three-dimensional, spatially controlled in vitro test systems, and to develop …


Assembly And Disassembly Of Myofibrils In Dissociated Cardiomyocytes, Honghai Liu May 2012

Assembly And Disassembly Of Myofibrils In Dissociated Cardiomyocytes, Honghai Liu

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Significance
1) We have developed a hybrid TPEF-SHG imaging system with an onstage incubator for long-term living-cell imaging. Using the imaging system, the assembly of myosin filaments onto the myofibrils can be investigated without fluorescently labeling the specific proteins, which enabled us to study the dynamic process of the assembly and dedifferentiation of myofibrils in living cardiomyocytes without labeling any sarcomeric proteins for long time.
2) We observed the addition of new sarcomeres during myofibrillogenesis while neonatal cardiomyocytes were spreading on the substrate for up to 10 hours under the customized TPEF-SHG imaging system. New-sarcomere addition at both the ends …


Bioengineering Approach To Understanding Tmj Pathobiology, Jonathan Kuo May 2012

Bioengineering Approach To Understanding Tmj Pathobiology, Jonathan Kuo

All Dissertations

The temporomandibular joint (TMJ) is a load-bearing joint consisting of the condyle of the mandibular bone, the fossa eminence of the temporal bone, and a fibrocartilaginous disc held in between the bone surfaces by ligaments. The TMJ disc serves to distribute stress, lubricate movement, and protect the articular surfaces of the joint. Over ten million Americans suffer from TMJ disorders (TMD) that affect the movement and function of the joint, making everyday tasks like talking and eating difficult and painful. A wide variety of treatments and surgeries have been proposed and undertaken with limited success based on the varying degree …


The Effects Of Coated Gold Nanorods On Porcine Atrioventricular Valve Tissues Using Atomic Force Microscopy, Heather L'Ecuyer May 2012

The Effects Of Coated Gold Nanorods On Porcine Atrioventricular Valve Tissues Using Atomic Force Microscopy, Heather L'Ecuyer

All Theses

In this Master's thesis we examine the effect of surface modified gold nanorods (AuNRs) coated with polyelectrolyte multilayers (PEMs) on the mechanical properties of porcine mitral valve tissue ex vivo. The presence of healthy mitral valve tissue in the body is important to ensuring unidirectional flow of blood through the systemic circuit. Unfortunately, due to its anatomic complexity and unique mechanical behavior, pathological mitral valve tissue remains difficult to treat with conventional methods. We hope that the knowledge gleaned from these studies could be useful for developing new and novel treatments treating pathological mitral valve mechanical properties.
Specifically, we examine …


Effects Of Different Microenvironmental Conditions On The Growth And Differentiation Of Dental Pulp Stem Cells, Matthew Cupelli May 2012

Effects Of Different Microenvironmental Conditions On The Growth And Differentiation Of Dental Pulp Stem Cells, Matthew Cupelli

All Theses

Human teeth are very complex structures that are susceptible to many different pathologies due to poor dental health. Currently, there are many restorative methods to reestablish some of the function that teeth have, but the materials used in these methods all have drawbacks and cannot fully mimic the native teeth. Tissue engineering research groups have begun to explore regenerating bone or dental tissue using mesenchymal stem cells derived from the bone marrow. However, our group focuses on regenerating dental tissues using multipotent stem cells from dental pulp.
Dental pulp stem cells (DPSCs) have shown similarities to bone marrow stem cells …


Development Of A Lower Extremity Mobility Assessment Methodology For Motor Vehicle Operation And Initial Validation, Justin Arnosky May 2012

Development Of A Lower Extremity Mobility Assessment Methodology For Motor Vehicle Operation And Initial Validation, Justin Arnosky

All Theses

Limited quantifiable data exists on lower extremity mobility and function during driving. To date, the most appropriate existing measures of successful driving function are assessed by a driving rehabilitation specialist during an on-road evaluation. Establishing the kinematic chain- or the order and magnitude in which joints are moved- during driving may prove to be a useful tool in lower extremity function assessment in drivers. To this end, a study was conducted instrumenting both the left and right legs of healthy licensed male drivers (18-26 years old) with a system of angle measuring goniometers (Biometrics, Ltd.) in a driving simulator (DriveSafety …


Electrochemical Capacitance Measurements To Study Molecular Surface Interactions, Nrutya Madduri May 2012

Electrochemical Capacitance Measurements To Study Molecular Surface Interactions, Nrutya Madduri

All Theses

The behavior of biological molecules such as proteins at the electrode/electrolyte has been of considerable interest for the development of biosensors. Several investigative techniques including Potentiometry, Voltammetry, Amperometry, and Electrochemical Impedance Spectroscopy are being employed to study and analyze these molecular surface interactions. Investigative techniques such as cyclic voltammetry involve the application of a large potential to probe the electrode characteristics and capture the bulk membranous events to obtain the required measurements. This study looks to achieve two major objectives through the use of a novel technique, namely, the double layer capacitive method: 1) to analyze the electrochemical behavior of …


Dynamic Endothelialization Of Aortic Heart Valve Scaffolds, Richard Pascal Jan 2012

Dynamic Endothelialization Of Aortic Heart Valve Scaffolds, Richard Pascal

All Theses

Cardiovascular disease is the number one killer worldwide affecting both the heart and blood vessels. Valvular heart disease can arise from calcification, and structural deterioration resulting in a stenotic or regurgitant valve incapable of proper function. With approximately 275,000 valve replacements performed annually worldwide, the need for replacement heart valves is well established. Currently, treatment of valvular heart disease is limited to two options (mechanical and bioprosthetic). Both replacement valves have their own drawbacks, which have driven research in the bioengineering field to focus on the development of a tissue engineered heart valve (TEHV) capable of growth and self-repair.
A …


Electrical Coupling Between Micropatterned Cardiomyocytes And Stem Cells, Zhen Ma Dec 2011

Electrical Coupling Between Micropatterned Cardiomyocytes And Stem Cells, Zhen Ma

All Dissertations

To understand how stem cells functionally couple with native cardiomyocytes is crucial for cell-based therapies to restore the loss of cardiomyocytes that occurs during heart infarction and other cardiac diseases. Due to the complexity of the in vivo environment, our knowledge of cell coupling is heavily dependent on cell-culture models. However, conventional in vitro studies involve undefined cell shapes and random length of cell-cell contacts in addition to the presence of multiple homotypic and heterotypic contacts between interacting cells. Thus, it has not been feasible to study electrical coupling corresponding to isolated specific types of cell contact modes.
To address …


Development Of A Dynamic In Vitro Model Of A Stented Blood Vessel To Evaluate The Effects Of Stent Strut Material Selection And Surface Coating On Smooth Muscle Cell Response, Bradley Winn Dec 2011

Development Of A Dynamic In Vitro Model Of A Stented Blood Vessel To Evaluate The Effects Of Stent Strut Material Selection And Surface Coating On Smooth Muscle Cell Response, Bradley Winn

All Dissertations

Cardiovascular disease is the leading cause of mortality in The United States and Europe, accounting for approximately half of all deaths. The most common form of cardiovascular disease is atherosclerosis, which is characterized by the formation of fatty atheromatous plaques that can grow to occlude the vessel lumen, thus causing ischemia distal to the occlusion. This is commonly treated using balloon angioplasty, which is usually done in conjunction with the deployment of a stent. Stent deployment helps hold the vessel open following the local injury caused by balloon inflation and prevents elastic recoil and subsequent negative remodeling. Stenting has been …


Characterizing Mechanical Heterogeneity In Cardiovascular Cells, Sandra Deitch Dec 2011

Characterizing Mechanical Heterogeneity In Cardiovascular Cells, Sandra Deitch

All Dissertations

Most tissue-level mechanical models assume homogeneous mechanical properties within a single cell type. However, measurements of cellular mechanical properties show large variability in whole-cell mechanical properties between cells from a single population. This heterogeneity has been observed in many cell populations and with several measurement techniques but the sources are not yet fully understood. Cell mechanical properties are directly related to the composition and organization of the cytoskeleton, which is physically coupled to neighboring cells through adherens junctions and to underlying matrix scaffolds through focal adhesion complexes. As such, we believe that this high level of heterogeneity can be attributed …


A Computational Investigation For Potential Improvements, Angela Grujicic Dec 2011

A Computational Investigation For Potential Improvements, Angela Grujicic

All Theses

Mild traumatic brain injury (mTBI), colloquially known as a concussion, is the most common injury in modern wars. This domination of mTBI is hypothesized to be due to a combination of unconventional explosives and better protection and care of the patients, increasing survivability. While the majority of the body is covered in armor, the head is left relatively unprotected. The current Advanced Combat Helmet (ACH) has been designed to protect the warfighter against ballistic impacts and impacts against a hard surface, with little to no regard to blast loading. Polyureas, a class of microsegregated, elastomeric copolymers, has been shown to …


'Exploring The Potential Of Using Antimicrobial Peptides And Copper Nanoparticles In Tackling Surgical Site Infections', Sriram Sankar Dec 2011

'Exploring The Potential Of Using Antimicrobial Peptides And Copper Nanoparticles In Tackling Surgical Site Infections', Sriram Sankar

All Theses

Postoperative wound site infections remain a major source of illness with approximately 500,000 infections per year, among an estimated 27 million surgical procedures. Such infections account for approximately one quarter of the estimated 2 million nosocomial infections in the United States which causes about 90,000 deaths each year. More than 70% of the bacteria that causes such infections are resistant to at least one of the antibiotics and result in longer hospitalization; besides requiring second option treatments that may be less effective, more toxic and expensive. Hence, there is a frenetic search for alternatives and in this regard, antimicrobial peptides …


Interfacial Force Field Parameterization Using The Dual Force Field Charmm Program For The Accurate Simulation Of Peptide-Surface Interaction, Nadeem Vellore Dec 2011

Interfacial Force Field Parameterization Using The Dual Force Field Charmm Program For The Accurate Simulation Of Peptide-Surface Interaction, Nadeem Vellore

All Dissertations

Protein adsorption to solid material surfaces is a complex phenomenon and various factors play a role in controlling these processes. Inherent limitations to understand these biological interactions using experimental approaches alone have led to the possibility of exploring these systems using computational molecular simulation methodologies. Before confidence can be placed on these computational protocols, however, rigorous validation of the applicability of these methods to accurately represent protein adsorption processes is needed. In this research, we evaluated the use of all-atom empirical force field (FF) based simulations using the CHARMM simulation program and FF for the study of peptide adsorption processes …


Methods Development And Force Field Evaluation For Molecular Simulations Of Interactions Between Structured Peptides And Functionalized Material Surfaces, Galen Collier May 2011

Methods Development And Force Field Evaluation For Molecular Simulations Of Interactions Between Structured Peptides And Functionalized Material Surfaces, Galen Collier

All Dissertations

The process of protein adsorption to material surfaces is highly complex and it is one of the most fundamental concepts upon which progress in the field of bioengineering is based. The strategic design of material surfaces for optimal utility in specific biological environments is absolutely dependent upon a thorough understanding of the mechanisms underlying protein adsorption, yet there is still a very limited understanding of these mechanisms. The primary reason for this lack of understanding is that protein adsorption is a dynamic process which occurs at the atomic and macromolecular scale, where experimental analyses provide a view that is static …


Novel Nanofiber Structures And Advanced Tissue Engineering Applications, Vince Beachley May 2011

Novel Nanofiber Structures And Advanced Tissue Engineering Applications, Vince Beachley

All Dissertations

Extracellular matrix (ECM) nanofibers such as collagen and elastin make up an important component of natural tissues. These structural components serve to impart mechanical strength and provide locations for cell attachment and biomolecule storage. Cells respond to their structural environment in a wide variety of ways beyond physical support, and it has been demonstrated that this environment directly modulates cell behaviors such as, morphology, differentiation, ECM production, attachment, and migration. ECM nanofibers also play an important role as a template for tissue formation during development, remodeling, and regeneration. Nanofiber based tissue engineering strategies aim to mimic the geometry of the …


Application Of Nanotechnology For Targeted Delivery Of Antibacterial Enzymes And For Enzyme-Based Coatings On Medical Devices And Implants, Rohan Satishkumar May 2011

Application Of Nanotechnology For Targeted Delivery Of Antibacterial Enzymes And For Enzyme-Based Coatings On Medical Devices And Implants, Rohan Satishkumar

All Dissertations

The frequency of S. aureus infection and subsequent biofilm formation associated with vascular catheterization has been increasing in recent years and often begins as a local colonization at the site of the catheter insertion. Antimicrobial enzymes and peptides, which are effective against a broad range of pathogens and low rates of resistance, have attracted attention as promising alternative candidates in treatment of infections caused by antibiotic resistant bacteria. The use of nanoparticles as carriers for enzymes, in addition to their size, charge, high surface area per volume etc. offers targeted delivery of enzymes to pathogenic bacteria. We proposed to use …