Biomedical Engineering and Bioengineering Commons^™

Modulation Of Bone And Nerve Cell Behavior Using Biodegradable Polymer Networks, Lei Cai

Doctoral Dissertations

This dissertation presents novel biodegradable and photo-crosslinkable building blocks to achieve polymer networks with controlled surface chemistry, stiffness, and topographical features for investigating cell-material interactions and targeting hard and soft tissue engineering applications. Chapter I reviews the recent progress in polymeric gel systems and how their physical properties can be tailored to regulate cell functions and satisfy the clinical needs. Chapter II presents a facile method to synthesize photo-crosslinkable poly(epsilon-caprolactone) acrylates (PCLAs) and reveal tunable cell responses to photo-crosslinked PCLAs. Chapter III investigates the mechanism of colorization in preparing crosslinkable polymers by reacting hydroxyl-containing polymers with unsaturated anhydrides or acyl …

Design Of Experimentation To Systematically Determine The Interaction Between Electrospinning Variables And To Optimize The Fiber Diameter Of Electrospun Poly (D, L-Lactide-Co-Glycolide) Scaffolds For Tissue Engineered Constructs, Yvette S. Castillo

Master's Theses

Cardiac disease causes approximately a third of the deaths in the United States. Furthermore, most of these deaths are due to a condition termed atherosclerosis, which is a buildup of plaque in the coronary arteries, leading to occlusion of normal blood flow to the cardiac muscle. Among the methods to treat the condition, stents are devices that are used to restore normal blood flow in the atherosclerotic arteries. Before advancement can be made to these devices and changes can be tested in live models, a reliable testing method that mimics the environment of the native blood vessel is needed. Dr. …

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 …

Co-Culture Of Smooth Muscle Cells And Endothelial Cells On Porous 3d Polyurethane Scaffolds For Vascular Tissue Engineering, Aparna Bhattacharyya

Electronic Thesis and Dissertation Repository

One of the challenges in the designing of clinically-relevant vascular substitutes is our lack of understanding on how vascular smooth muscle cells (VSMCs) and vascular endothelial cells (VECs) interact in the graft. The aim of this study was to examine the factors that play a role in VSMC and VEC interaction in 3D co-culture. Highly porous 3D poly(carbonate urethane) scaffolds were fabricated using a solvent casting and particulate leaching method. VSMCs and VECs were co-cultured for 48 hours. Immunofluorescence staining showed that VSMCs readily attached to the scaffold and formed dense confluent layers which facilitated the organization of VECs of …

Biomaterial-Microvasculature Interactions, Alisha Sarang-Sieminski, Keith Gooch

Alisha L. Sarang-Sieminski

The utility of implanted sensors, drug-delivery systems, immunoisolation devices, engineered cells, and engineered tissues can be limited by inadequate transport to and from the circulation. As the primary function of the microvasculature is to facilitate transport between the circulation and the surrounding tissue, interactionsbetween biomaterials and the microvasculature have been explored to understand the mechanisms controlling transport to implanted objects and ultimately improve it. This review surveys work on biomaterial-microvasculature interactions with a focus on the use of biomaterials to regulate the structure and function of the microvasculature. Several applications in which biomaterial-microvasculature interactions play a crucial role are briefly …

Evaluation Of Decellularization Procedures For Porcine Arteries, Charles Clapp

Biomedical Engineering

Coronary artery disease has become the leading cause of death in the United States, with over 425,000 deaths in 2006. Stenting has evolved into the preferred preventative technique for myocardial infarction by opening up an occluded artery, due to its low invasiveness compared to the alternative of coronary artery bypass grafting. Bare metal stents have been improved by coating with anti-proliferative drugs to advance their effects, but even drug eluting stents still have a risk of restenosis, thrombus formation, and necessary revascularization. Continual advancement in stent design necessitates faster, effective pre-clinical evaluation techniques. Kristen Cardinal, Ph.D., developed the blood vessel …

Investigation Of A New Material For Heart Valve Tissue Engineering, Claire Brougham, Nian Shen, Allison Cudsworth, Thomas Flanagan, Stefan Jockenhoevel, Fergal O'Brien

Conference Papers

No abstract provided.

A Novel In-House Design Of A Bioreactor For The Modeling Of An In Vitro Blood Brain Barrier Model, Ian Mahaffey

Biomedical Engineering

The blood brain barrier is the protector of the central nervous system and a physical barrier that functions to regulate the substances that can pass in and out of the brain; it is the function and integrity of this system that keeps the homeostasis of the central nervous system. Yet this shield against foreign invaders in the blood also prevents drugs designed for treatment of various ailments of the central nervous system from reaching their target in the brain. Developing drugs that can pass through this barrier, and understanding it’s function has become an area of increasing interest. Many researchers …

Shape-Shifting Surfaces For Rapid Release And Direct Stamping Of Organized Micro-Tissues, Samuel James Dupont

USF Tampa Graduate Theses and Dissertations

The primary aim of the research in this study is to develop a robust and simple platform for the in vitro organization of cells on surfaces which facilitate rapid cell release and allows for the direct stamping of highly organized micro-tissues. Current approaches towards this goal have been very successful but are lengthy and subject cells to harsh conditions for extended periods of time raising questions regarding cell health and maintenance of physiological state. To address these concerns a platform was developed to allow for rapid cell release by utilizing a release mechanism different from previous work.

Micron-scale structures comprised …

Magic From Human Regenerative Technologies -- Stem Cells, John M. Ritz

STEMPS Faculty Publications

The article discusses the developments in stem cell research and development. It mentions that through tissue engineering or regenerative medicine, many diseases are finding techniques for improvement and cure. It discusses the role of stem cells in mending the human body and the ethics associated with this technology . It is mentioned that stem cells are divided in 2 types: embryonic stem cells and adult stem cells. It includes the process of cell differentiation which determines the properties and characteristics of cells. It mentions several diseases related to sports injury, spinal cord injuries, blood and heart disorders to be to …

Micropatterned Electrospun Nanofibrous Substrates As Scaffolds For Engineered Salivary Glands, David Alexander Soscia

Legacy Theses & Dissertations (2009 - 2024)

The salivary gland is a complex organ exhibiting a branching, 3-dimensional structure made up of acinar (saliva-producing), and ductal (saliva transporting and modifying) epithelial cells. The high surface area of the gland allows it to efficiently provide the mouth with saliva, maintaining oral cleanliness and comfort. Salivary gland hypofunction, a significant clinical problem often caused by the autoimmune disease Sjögren's syndrome or head and neck radiation for cancer patients, affects millions of Americans and is characterized by a loss of function of salivary gland acinar cells. Chronic xerostomia, or dry mouth, arises as a result of salivary gland hypofunction and …

Tissue Engineering An Acellular Bioresorbable Vascular Graft To Promote Regeneration, Patricia Wolfe

Theses and Dissertations

Tissue engineering is an interdisciplinary field that aims to restore, maintain, or improve diseased or damaged tissues. Electrospinning has become one of the most popular means to fabricate a scaffold for various tissue engineering applications as the process is extremely versatile and inexpensive. The ability for electrospinning to consistently create nanofibrous structures capable of mimicking the native extracellular matrix (ECM) is the basis behind why this technique is so successful in tissue engineering. Cardiovascular disease has been the leading cause of death in the United States for over 100 years, and because of this, the need for coronary artery replacements …

Development Of An In-Vitro Hyperglycemic Tissue Engineered Blood Vessel Mimic, Brian C. Wong

Biomedical Engineering

No abstract provided.

A 3-Dimensional Vascularized Cardiac Tri-Culture Model Using Chitosan Nanofiber Scaffolds, Ali Hussain

Dissertations

The development of an in vitro tissue model that can mimic the 3-dimenisonal (3-D) cellular architecture and mosaic of myocardial tissue holds great value for cardiac tissue engineering, modeling, and cardiovascular drug screening applications. The main objective of this project was to develop a 3-D vascularized cardiac tissue model in vitro for improved survival and function.

The cellular mosaic of the myocardial tissue demands the intricate integration of an extracellular matrix-like scaffold, cellular constituents, and biological factors. The first aim of the research was to fabricate and characterize a biodegradable chitosan nanofiber scaffold that would resemble the extracellular matrix (ECM) …

Development Of Physiologic Contact Models For Articular Surfaces, John Owen

Theses and Dissertations

The superficial tangential zone (STZ) plays a significant role in normal articular cartilage’s ability to support loads and retain fluids. To date, tissue engineering efforts have not replicated normal STZ function in cartilage repairs. Finite element models were developed to examine the STZ’s role in normal and repaired articular surfaces under different contact conditions. Models were developed by incrementally adding improvements which culminated in contact loading of curved models by permeable and impermeable rigid surfaces and a normal cartilage layer. In the normal STZ, permeability was strain-dependent on volumetric strain; tension-compression nonlinearity modeled collagen behavior. Nonlinear geometry accounted for finite …

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 …

A Study On The Applications And Toxicity Assessments Of Carbon Nanotubes In Tissue Engineering, Rena Baktur

All Graduate Theses and Dissertations, Spring 1920 to Summer 2023

Carbon nanotubes (CNTs) are one of the most popular nanomaterials. There has been increasing interest in the development and applications of carbon nanotubes due to their huge potential in industrial and medical applications. Recent applications of carbon nanotubes include development of scaffolds and drug delivery systems. Despite rapidly emerging applications of CNTs, little is known about the impact of CNTs on cellular processes, especially mesenchymal stem cell (MSC)'s differentiation. Also, the effects of nanoparticle exposure under different conditions on cellular responses have not been well characterized yet.

To characterize the effects of CNTs on creating nanoscale scaffolds for tissue engineering, …

One-Dimensional Radial Diffusion Of Small Molecules (376 Da) In Bone Tissue, Kurt W. Farrell

ETD Archive

The flow of nutrients through any biological tissue is important to maintain homeostasis. If the transport process is understood, medical research teams can better design medications, prosthetic implants, and tissue scaffolds. Additionally, transport rates help physicians to better understand disease states and wound healing, including minor injuries such as breaks and sprains, which will aid in better diagnoses. We developed a novel method that measures the rate of diffusion in vitro, of fluorescein sodium salt. Samples were incubated at 37°C in a 5 CO2 atmosphere for various periods of time. Samples were sliced and analyzed using Image-Pro Plus and MATLAB …

Characterization And Evaluation Of A Novel Tissue Engineered Aortic Heart Valve Construct, Mary Tedder

All Dissertations

Tissue engineering holds great promise for treatment of valvular diseases. Scaffolds for engineered heart valves must function immediately after implantation, but must also permit repopulation with autologous host cells and facilitate gradual remodeling.
Native aortic heart valves are composed of three layers, i.e. two strong external fibrous layers (ventricularis and fibrosa) separated by a central, highly hydrated spongiosa. The fibrous layers provide strength and resilience while the spongiosa layer facilitates shearing of the external layers. Our working hypothesis is that partially cross-linked collagen scaffolds that closely mimic the layered histo-architecture of the native valve would fulfill these requirements. To test …

Evaluation Of Factors That Modulate Cellular Adipogenesis For Breast Tissue Engineering Strategies, Cheryl Gomillion

All Dissertations

It is estimated that this year more than 200,000 women in the United States will be diagnosed with breast cancer. Treatment for most occurrences of breast cancer will often include surgical removal of the tumorigenic tissue, resulting in a soft tissue defect within the subcutaneous tissue of the skin. Post-surgical reconstruction methods are often sought by patients to restore the aesthetic function of the breast via cellular or non-cellular methods; however, because of complications associated with currently used methods for breast reconstruction, researchers are investigating tissue engineering methods to produce viable autologous adipose tissue for breast reconstruction.
Previous research in …

Effect Of Mechanical Stimulation On Mesenchymal Stem Cell Seeded Cartilage Constructs, Karin Wartella

Theses and Dissertations

Cartilage tissue engineered constructs using mesenchymal stem cells were stimulated with 3 different stimulation algorithms to achieve characteristics mimicking the superficial tangential zone of articular cartilage. The stimulation algorithm of both compression and tension without an offset had the best properties out of all the evaluated groups.

Igf-I Releasing Plga Scaffolds For Growth Plate Regeneration, Sharath Kumar Chinnakavanam Sundararaj

University of Kentucky Master's Theses

Growth plate is a highly organized cartilaginous tissue found at the end of long bones and is responsible for longitudinal growth of the bones. Growth plate fracture leads to retarded growth and unequal limb length, which might have a lifelong effect on a person’s physical stature. This research is a tissue engineering approach for the treatment of growth plate injury. Insulin-like growth factor I (IGF-I), which can stimulate cartilage formation, was encapsulated within PLGA microspheres that were then used to form porous scaffolds. The release profile of the IGF-I from the PLGA scaffold showed a biphasic release pattern. In vitro …

Design, Development And Biomechanical Analysis Of Scaffolds For Augmentation Of Rotator Cuff Repairs, Amit Aurora

ETD Archive

Rotator cuff tears are a source of debilitating pain that commonly affects more than 40 of our aging population. Despite advances in surgical treatment, the failure rate of rotator cuff repairs is as high as 20-90 . Extracellular matrix (ECM) derived scaffolds have recently been investigated as augmentation devices for rotator cuff repairs, but none has yet demonstrated both the appropriate biological and mechanical properties for mitigating re-tears and enhancing healing. This dissertation proposes to engineer the mechanical properties of allograft fascia lata in a manner that will allow its use as an augmentation device for rotator cuff repairs. This …

Surface Microtopography Modulation Of Biomaterials For Bone Tissue Engineering Applications, Eun Jung Kim

ETD Archive

The ultimate goal of this project is to develop a biodegradable and implantable scaffold with precise surface topographies that can provide osteoconductive stimuli to connective tissue progenitor cells (CTPs), and subsequently, enhance bone regeneration applications without the complications of autogenous cancellous bone grafts. This dissertation presents the modification of surface microtextures to provide osteoconductive stimuli to CTPs for bone regeneration applications. First, the effect of surface topography on cell proliferation and osteogenic differentiation was validated through experiments using surface post microtextures and CTPs. Post microtextures accelerated CTP growth behaviors compared to smooth polydimethylsiloxane (PDMS) and standard cell culture dishes. Second, …

Preparation And Characterization Of Electrospun Poly(D, L-Lactide-Co-Glycolide) Scaffolds For Vascular Tissue Engineering And The Advancement Of An In Vitro Blood Vessel Mimic, Tiffany Richelle Pena

Master's Theses

PREPARATION AND CHARACTERIZATION OF ELECTROSPUN POLY(D,L-LACTIDE-CO-GLYCOLIDE) SCAFFFOLDS FOR VASCULAR TISSUE ENGINEERING AND THE ADVANCEMENT OF AN IN VITRO BLOOD VESSEL MIMIC

Tiffany Richelle Peña

Currently, an estimated 1 in every 3 adult Americans are affected by one or more cardiovascular complications. The most common complication is coronary artery disease, specifically atherosclerosis. Outcomes of balloon angioplasty treatments have been significantly improved with the addition of drug eluting stents to the process. Although both bare metal and drug eluting stents have greatly increased the effectiveness of angioplasty and decreased the occurrence of restenosis, several complications still exist. For this reason, the stent …

A Pulsatile Bioreactor For Conditioning Tissue Engineered Heart Valves, Leslie Sierad

All Theses

Tissue engineered constructs with autologous adult stem cells capable of self-repair and growth are highly desired replacements for diseased heart valves. However, the current approaches have inadequate mechanical properties to withstand in vivo implantation. Therefore, our group hypothesized that an in vitro environment of physiological intra-cardiac pressures and flow will stimulate stem cells to differentiate and remodel valvular scaffold constructs before implantation.
The group developed a pneumatic-driven conditioning system (Aim I) consisting of a three-chambered heart valve bioreactor, a pressurized compliance tank, a reservoir tank, one-way valves, pressure-retaining valves, and pressure transducers. The system can be sterilized using conventional autoclaving …

Applied Electrokinetics For Tissue Engineering Applications, Stephanie R. Tully-Dartez

Doctoral Dissertations

Tissue engineering could provide an alternative source of transplant tissue regardless of donor supply and with reduced risk of immune rejection. Engineered tissue requires three critical components for successful development: the cells, growth factors, and the scaffold on which they will initially grow. The scaffold acts as a temporary extracellular matrix (ECM) allowing cell attachment and acclimation to the environment prior to synthesis and construction of the cell's native ECM. Prior to cell seeding, the scaffold must be characterized to determine whether or not the pore geometry is conducive to cell implantation. Electrochemical impedance spectroscopy (EIS) provides a unique and …

Imaging Of Tyramine-Substituted Hydrogels For Tissue Replacement, Ediuska V. Laurens

ETD Archive

Novel tyramine-based hyaluronan (HA) and collagen hydrogels have been developed in which cross-linking is accomplished via peroxidase-mediated dityramine linkages allowing direct cross-linking in vivo. These TB hydrogels possess advantageous physical properties, which include excellent biocompatibility and the ability to mimic the biological, structural and mechanical properties of normal, healthy tissues, including cartilage, and thus provide for synthetic, implantable biomaterials suitable for a wide range of tissue types. The efficacy of these TB-hydrogels has been previously tested in a number of clinically relevant animal models, which have evaluated their applicability for the repair/replacement of various tissues, including cartilage. Nevertheless, there exists …

Cortical Bone Tissue Engineering;Scaffold Design And Cell Selection, Demin Wen

ETD Archive

Cortical bone tissue engineering provides a promising approach to generate graft materials needed to treat the large sized bone defects. The underling premise of tissue engineering is to mimic the in vivo microenvironment as best as possible in vitro culture system. To select an appropriate scaffold material used in this model system, mechanical and hydraulic permeability properties of 316L porous stainless steel and polymethylmethacrylate (PMMA) were studied, as well as their biocompatibility in short and long term cell culture. Results showed that scaffolds made of both stainless steel and PMMA: (1) could be manufactured to have similar permeability as that …

Design And Optimization Of A Blood Vessel Mimic Bioreactor System For The Evaluation Of Intravascular Devices In Simple And Complex Vessel Geometries, Sara M. Leifer

Master's Theses

Coronary artery disease affects millions of people and the ability to detect and treat the disease is advancing at a rapid rate. As a result, the development of intravascular technologies is the focus of many medical device manufacturers. Specifically, coronary stent implantation is being performed in an increasing number of patients and a number of new stent designs have been introduced to the market, resulting in the need for improved preclinical testing methods. An in vitro tissue engineered “blood vessel mimic” (BVM) system has previously been established and its feasibility for the initial testing of newly emerging intravascular technology has …