Biomedical Engineering and Bioengineering Commons^™

Evaluation Of Polyvinyl Alcohol (Pva) For Electrospinning Utility In The Blood Vessel Mimic (Bvm) Lab, Logan Vandenbroucke

Master's Theses

Electrospinning has provided the opportunity to create extracellular matrix (ECM) mimicking scaffolds for the development of tissue-engineered constructs. Within Professor Kristen Cardinal’s Blood Vessel Mimic (BVM) Lab, at Cal Poly, there exists a constant demand for innovation and the expansion of polymer types and electrospinning capabilities for its BVM model. Along these lines, the BVM Lab has recently acquired two new electrospinning systems: the Spinbox, a commercially graded electrospinning system, and the Learn-By-Doing system, which was part of a recently completed thesis conducted by Jason Provol. Additionally, recently published literature has demonstrated polyvinyl alcohol (PVA) as a viable option for …

Effect Of Human Decellularized Skeletal Muscle On Recovery From Volumetric Muscle Loss Injury, Jacob Schluns

Graduate Theses and Dissertations

Volumetric muscle loss (VML) overwhelms muscle’s robust capacity for regeneration. A key event in the etiology of VML injury is the bulk loss of structural cues provided by the underlying extracellular matrix (ECM). While muscle is a highly structured tissue, with cell and ECM alignment in the direction of contractile force production, the impact of scaffold alignment on recovery remains unclear. Bulk human decellularized skeletal muscle (DSM) tissues were sectioned into 10 x 1-2 mm fibers. VML defects were repaired using multi-fiber implants consisting of approximately 8 fibers per defect arranged into two layers. Fibers were oriented 1) to the …

Preparing Homogenous Composites Of Collagen And Cellulose Nanocrystals For Tissue Engineering Research, Zachary Stanley

Biological and Agricultural Engineering Undergraduate Honors Theses

Advancements in medicine and our understanding of stem cells have led to a greater emphasis on further developing research focused on tissue engineering. This research has led to the rise of both two-dimensional and three-dimensional scaffolds that can be utilized to repair bone, skin, vascular, and potentially even nervous tissue. One of the prominent compounds used in modern scaffolds is collagen-based hydrogels due to their low antigenicity and ability to provide structure to cells. There is potential to further improve upon this three-dimensional scaffold by incorporating cellulose nanocrystals (CNCs) into a composite hydrogel with collagen. The addition would increase the …

In Vitro Bioreactor For Mechanical Control And Characterization Of Tissue Constructs, Samuel Coeyman

All Dissertations

Heart failure (HF) currently affects over 6 million Americans, 50% of whom die within 5 years of their initial diagnosis. A major contributor to the onset of HF is cardiac fibrosis in the myocardium, which arises when fibroblasts (FBs) are activated in response to heightened mechanical stress from overload conditions like hypertension. Activated FBs remodel the extracellular matrix (ECM) and secrete ECM proteins including collagen. FB remodeling has been studied in the past by applying forces and/or deformations to three-dimensional, cell-seeded gels and tissue constructs in vitro. Unfortunately, previous stretching platforms have traditionally not enabled mechanical property assessment to be …

Development Of A Tissue Engineered Cardiac Patch, Howard Herbert

All Dissertations

Cardiovascular Disease(CVD) is the leading cause of mortality in the developed world. CVD is most commonly manifested as atherosclerosis of the coronary arteries leading to Myocardial Infarction(MI). After MI, fibrosis of the ventricular wall leads to heart failure(HF), a pandemic affecting 26 million people globally. While therapies are continuously developed to combat HF, the treatment of choice, whole heart transplant, is limited by the availability of donor hearts. It is clear that there is a need to develop a long-term solution to combat HF and its enormous economic burden. Tissue Engineering and Regenerative Medicine holds promise as a possible solution …

Fumarate-Based Polymers: Oligo(Poly(Ethylene Glycol) Fumarate) And Poly(Butylene Fumarate) For Tissue Engineering Heart Valve And Bone Tissue, Christian T. Denny

Biomedical Engineering ETDs

Tissue engineering is an emerging field that came from the fields of medicine, materials science, and engineering. The foundation of tissue engineering uses a paradigm that incorporates cells, biomaterials, and exogenous factors to create living tissues for medical, pharmaceutical, and research purposes. Within the last 100 years, biomaterials have been developed to solve many medical and research problems. As biomaterials have developed throughout the years new materials have been developed to have specific properties appropriate for medical applications. Fumarate is a naturally derived molecule in the body and has been found useful for developing polyesters that can be crosslinked into …

Controlled Codelivery Of Mir-26a And Antagomir-133a With Osteoconductive Scaffolds To Promote Healing Of Large Bone Defects, Cole J. Ferreira

Masters Theses

Often caused by trauma or tumor removal, large bone defects frequently result in delayed or non-union. The current gold standard for treatment is autograft. However, due to limitations, such as the size and location of the defect, these cannot always be utilized. A common alternative to autograft is the use of BMP-2 with a collagen scaffold, however, this treatment is limited by numerous side effects. In recent years, genetic materials such as microRNAs (miRNAs) have offered possible alternative therapies. MiRNAs are small non-coding RNA molecules that generally range from 20-24 nucleotides, serve as repressors of gene expression, and are involved …

Bone And Cartilage Compression Simulator, Karoline M. Wucherer, Benjamin A. Parmentier, Thomasina E. Hinkle

Biomedical Engineering

A device was developed that delivers mechanical loads to bone and soft tissue samples under physiological conditions to aid in the research of tissue engineering bone and cartilage. To begin the design process, a Network Diagram and Gantt Chart were produced to create a general timeline for the project to follow. This allowed us to measure our progress and determine what effects (if any) delays could have on our project.

Towards The Systematic Evaluation Of Variable Modes Of Mechanical Conditioning On The Compositional, Microstructural And Mechanical Properties Of Engineered Tissue Vascular Grafts., Sarah Saunders

Theses and Dissertations

Coronary artery bypass surgery (CABG) remains one of the most common cardiac surgical procedures performed worldwide, frequently involving multiple bypasses, and commonly employing the patient’s internal mammary artery, radial artery, or saphenous vein. CABG is often not possible because native vessels were already employed in previous interventions or are diseased themselves. Synthetic vascular grafts are currently integral tools of vascular surgery and have had relative success in large-caliber applications providing substantial benefit to aortic or iliac grafting; however, small diameter (< 6 mm) arterial grafts have not yet translated into clinical effectiveness due to thrombosis and anastomotic intimal hyperplasia. ETVGs present an exciting potential alternative in vascular grafting by offering a blood vessel substitute that could exhibit all the functional characteristics of native vasculature. In addition to relieving supply limitations associated with coronary artery bypass surgery ETVGs are especially ideal for pediatric patients with congenital heart disease who require grafts that grow as they do, eliminating the need for reoccurring invasive surgeries.

Though the role of biomechanics in regulating cellular behavior promoting non-thrombogenicity, vasoactivity, and ECM synthesis and maintenance is well …

Understanding And Improving Adult Stem Cells For Cartilage Tissue Engineering, Dakota Katz

McKelvey School of Engineering Theses & Dissertations

Articular cartilage allows for near frictionless joint movement; however, when damaged the tissue has very little capacity for self-repair. Tissue engineering can be used to both repair damaged articular cartilage and as an in vitro model for joint disease. Commonly used cell sources for tissue engineering are adipose-derived and bone marrow-derived mesenchymal stem cells (ASCs and MSCs) because they can be patient matched, expand rapidly in culture, and have multipotent differentiation potential. However, donor-to-donor variability of differentiation potential can mask the results of in vitro experiments and ASCs and MSCs only retain their multipotency for a limited number of passages. …

Engineering Nucleus Pulposus Cell-Matrix Interactions With Laminin Ligands For Tissue Regeneration, Julie Elizabeth Speer

McKelvey School of Engineering Theses & Dissertations

Low back pain and degenerative conditions of the intervertebral disc (IVD) represent major global socioeconomic and medical burdens. The structures that comprise the IVD including the anulus fibrosis and the nucleus pulposus (NP) work together to stabilize the axial skeleton and distribute mechanical forces. However, the degenerative cascade, which is thought to begin with changes to the NP, results in alterations to the disc that can be seen across length scales including elongated cell shapes, tissue dehydration, and loss of disc height. Patients who present clinically with these changes may also experience altered biomechanics, pain upon motion, impairments to their …

Developing Aligned Nerve Scaffolds In A 3d Type-I Collagen Gel, Gabriel David

Biomedical Engineering Undergraduate Honors Theses

Despite significant progress in the field of peripheral nerve repair, clinical success is still limited, leaving millions to suffer from peripheral neuropathy with billions spent every year for treatment. Nerve repair methods that are capable of maximizing the regenerative properties of peripheral nerves are greatly desired in the field of medical science. This research aims to fill the gap between modern methods and the future of nerve repair by creating type-I collagen scaffolds with aligned degradation pores that will assist and nurture nerves growing through them. This is achieved by incorporating adipose stem cells into type-I collagen hydrogels and aligning …

Peptoid-Based Microsphere Coatings For Biomaterial Applications, Jesse Leland Roberts

Graduate Theses and Dissertations

Peptoids are peptidomimetic oligomers that predominantly harness similarities to peptides for biomimetic functionality. The incorporation of chiral, aromatic side chains in the peptoid sequence allows for the formation of distinct secondary structures and self-assembly into supramolecular assemblies, including microspheres. Peptoid microspheres can be coated onto substrates for potential use in biosensor technologies, tissue engineering platforms, and drug-delivery systems. They have the potential for use in biomedical applications due to their resistance to proteolytic degradation and low immunogenicity. This dissertation focuses on the physical characteristics and robustness of the peptoid microsphere coatings in various physiological conditions, along with their ability to …

Using A Lubricin Reporter Cell To Test Current Vs. Optimized Media Compositions, Sean M. Kennedy

Honors Undergraduate Theses

Osteoarthritis is a joint disease characterized by the breakdown of articular cartilage. The field of tissue engineering is interested in developing methods to produce biological alternatives to current orthopedic procedures. Lubricin is a molecule which is important in the proper lubrication of articular cartilage. It is a challenge in the field of tissue engineering to produce cartilage with sufficient lubricin expression. Developing a reporter cell for lubricin allowed for a more efficient investigation of the conditions wh­­­ich may influence its expression. By comparing "optimized" and traditional media solutions, it was determined that the use of a previously reported type II …

Development Of An Injectable Methylcellulose Hydrogel System For Nucleus Pulposus Repair And Regeneration, Nada A. Haq-Siddiqi

Dissertations and Theses

Low back pain is the most common cause of disability in the world and is often caused by degeneration or injury of the intervertebral disc (IVD). The IVD is a complex, fibrocartilaginous tissue that allows for the wide range of spinal mobility. Disc degeneration is a progressive condition believed to begin in the central, gelatinous nucleus pulposus (NP) region of the tissue, for which there are few preventative therapies. Current therapeutic strategies include pain management and exercise, or surgical intervention such as spinal fusion, none of which address the underlying cause of degeneration. With an increasingly aging population, the socioeconomic …

Elucidating Mechanisms Of Metastasis With Implantable Biomaterial Niches, Ryan Adam Carpenter

Doctoral Dissertations

Metastasis is the leading cause of cancer related deaths, yet it remains the most poorly understood aspect of tumor biology. This can be attributed to the lack of relevant experimental models that can recapitulate the complex and lengthy progression of metastatic relapse observed in patients. Mouse models have been widely used to study cancer, however they are critically limited to study metastasis. Most models generate aggressive metastases in the lung without the use of unique cell lines or specialized injection techniques. This limits the ability to study disseminated tumor cells (DTCs) in other relevant metastasis prone tissues. Prolonged observation of …

Manipulation And Patterning Of Mammalian Cells Using Vibrations And Acoustic Forces, Joel Cooper

USF Tampa Graduate Theses and Dissertations

Recently, there has been a surge in researchers and scientists investigating different methods which move, manipulate, and pattern biological cells. Multiple different mechanisms can be used for cellular manipulation, microfluidics, biochemical queues, and even optics, just to name a few. However, all techniques have their downsides. A majority of these methods require expensive equipment or reagents and can only manipulate a small number of cells at a time.

Some of the most common cell manipulation devices utilize acoustic pressure waves to move the cells to desired locations. Currently, it is unknown what level of force from these types of devices …

In Vitro Atherosclerosis Disease Model Via The Ring Stacking Method, Cameron Brandon Pinnock

Wayne State University Dissertations

Creation of an in vitro atherosclerotic disease model using the novel Ring Stacking Method. Singular self-assembling tissue rings made up smooth muscle cells and fibrin hydrogel are stacked on one another to create a tissue engineered vessel. These biologically engineered blood vessels are then seeded with endothelial cells via combined static rotational and dynamic bioreactor in order to create a functional intima layer. Early stage atherosclerosis was induced via the addition of oxidized low-density lipoproteins (ox-LDL) to the fibrin hydrogel that creates the media layer of the engineered vessel. After the creation of the intima layer the engineered vessel was …

Artificial Synthetic Scaffolds For Tissue Engineering Application Emphasizing The Role Of Biophysical Cues, Samerender Nagam Hanumantharao

Dissertations, Master's Theses and Master's Reports

The mechanotransduction of cells is the intrinsic ability of cells to convert the mechanical signals provided by the surrounding matrix and other cells into biochemical signals that affect several distinct processes such as tumorigenesis, wound healing, and organ formation. The use of biomaterials as an artificial scaffold for cell attachment, differentiation and proliferation provides a tool to modulate and understand the mechanotransduction pathways, develop better in vitro models and clinical remedies. The effect of topographical cues and stiffness was investigated in fibroblasts using polycaprolactone (PCL)- Polyaniline (PANI) based scaffolds that were fabricated using a self-assembly method and electrospinning. Through this …

Development Of Investment Casting Method For Production Of Metal Foams For Tissue Engineering, Justin Aaron Womack

Theses and Dissertations

Ideal biomaterials for bone tissue regeneration are bone-mimicking structures that present a fully interconnected porous structure, have similar mechanical properties to bone, and exhibits a specific biodegradation behavior that is at the same rate as adjoining cell growth. Metals have high wear resistance, ductility, impact strength, and strain energy absorption capacity compared to other materials, which makes them suitable candidates for tissue engineering scaffolds. Magnesium and zinc are of interest for bone tissue regeneration for their biocompatibility and mechanical properties close to human bone. A newly developed process, presented in this thesis, for the creation of porous magnesium and zinc …

Customization Of Aneurysm Scaffold Geometries For In Vitro Tissue-Engineered Blood Vessel Mimics To Use As Models For Neurovascular Device Testing, Camille D. Villadolid

Master's Theses

Cerebral aneurysms occur due to the ballooning of blood vessels in the brain. Rupture of aneurysms can cause a subarachnoid hemorrhage, which, if not fatal, can cause permanent neurologic deficits. Minimally invasive neurovascular devices, such as embolization coils and flow diverters, are methods of treatment utilized to prevent aneurysm rupture. The rapidly growing market for neurovascular devices necessitates the development of accurate aneurysm models for preclinical testing. In vivo models, such as the rabbit elastase model, are commonly chosen for preclinical device testing; however, these studies are expensive, and aneurysm geometries are difficult to control and often do not replicate …

Fluid Delivery System For A Cell Culture On A Microfluidic Chip, Austin J. Roeder, Colleen A. Richards, Emily A. Matteson

Biomedical Engineering

This project report provides a description of the progress made in the development of a fluid delivery system for a microfluidic cell culture on a chip. The system is intended to be used in a humidified incubator in a university laboratory and the fluid delivery system is required to exist and operate within that incubator for extended periods of time. Therefore, the system will be gravity-driven and contain no electronic components. The key specification of the system is to provide fluid flow at a constant velocity.

After manufacturing and testing the device, all specifications were met except for the fluid …

Engineering The Alveolar Gas Exchange Barrier With Extracellular Matrix Coatings For Bioengineered Lungs, Bethany M. Young

Theses and Dissertations

Lower respiratory diseases are currently the third leading cause of death worldwide. For many end-stage patients with these diseases, there is no cure and a shortage of donor organs available for transplant. A promising solution is to design regenerative scaffolds or complete bioengineered lungs, using decellularized lung tissues as a template for regeneration. Recent advances in the field have made significant strides towards developing a transplantable lung. However, the current technology has not produced a functional lung for in vivo transplant due to immature gas exchange barriers. The mechanisms driving alveolar barrier maturation and role that extracellular matrix (ECM) plays …

Chemically Modified Monolayer Surfaces Influence Valvular Interstitial Cell Attachment And Differentiation For Heart Valve Tissue Engineering, Matthew N. Rush

Nanoscience and Microsystems ETDs

As a cell mediated-process, valvular heart disease (VHD) results in significant morbidity and mortality world-wide. In the US alone, valvular heart disease VHD is estimated to affect 2.5% of the population with a disproportionate impact on an increasing elderly populous. It is well understood that the primary driver for valvular calcification is the differentiation of valvular interstitial cells (VICs) into an osteoblastic-like phenotype. However, the factors leading to the onset of osteoblastic-like VICs (obVICs) and resulting calcification are not fully understood and a more complete characterization of VIC differentiation and phenotypic change is required before treatment of valve disease or …

Determinants Of Multi-Scale Patterning In Growth Plate Cartilage, Alek Erickson

Theses & Dissertations

ABSTRACT

Functional architectures of complex adaptive systems emerge by dynamic control over properties of individual components. During skeletal development, growth plate cartilage matches bone geometries to body plan requisites by spatiotemporally regulating chondrocyte actions. Bone growth potential is managed by the proximodistal patterning of chondrocyte populations into differentiation zones, while growth vectors are specified by the unique columnar arrangement of clonal groups. Chondrocyte organization at both tissue and cell levels is influenced by a cartilage-wide communication network that relies on zone-specific release and interpretation of paracrine signals. Despite genetic characterization of signaling interactions necessary for cartilage maturation, the regulatory mechanisms …

Three-Dimensional Endothelial Spheroid-Based Investigation Of Pressure-Sensitive Sprout Formation, Min Song

Theses and Dissertations--Biomedical Engineering

This study explored hydrostatic pressure as a mechanobiological parameter to control in vitro endothelial cell tubulogenesis in 3-D hydrogels as a model microvascular tissue engineering approach. For this purpose, the present investigation used an endothelial spheroid model, which we believe is an adaptable microvascularization strategy for many tissue engineering construct designs. We also aimed to identify the operating magnitudes and exposure times for hydrostatic pressure-sensitive sprout formation as well as verify the involvement of VEGFR-3 signaling. For this purpose, we used a custom-designed pressure system and a 3-D endothelial cell spheroid model of sprouting tubulogenesis. We report that an exposure …

Oxygen Transport, Shear Stress, And Metabolism In Perfused Hepatocyte-Seeded Scaffolds With Radial Pore Architecture: Experimental And Computational Analyses, Chijioke Mbanu

Wayne State University Dissertations

Several modalities have been proposed as treatments or temporary stop-gap for patients suffering from liver failure until a suitable organ is available. However there is still an urgent need for an off-the-shelf device that can accommodate clinically relevant cell numbers, be cultured at physiological oxygen tensions and, can be fully integrated into and heal the injured hepatic space. In this study we investigated the effects that convective and direct oxygenation had on hepatocyte functionality, morphology and viability while cultured in bulk 3D chitosan scaffolds and perfusion bioreactor systems. Cylindrical chitosan scaffolds with radial directed pore structures were fabricated by a …

Polysaccharide-Based Shear Thinning Hydrogels For Three-Dimensional Cell Culture, Vasudha Surampudi

Theses and Dissertations

The recreation of the complicated tissue microenvironment is essential to reduce the gap between in vitro and in vivo research. Polysaccharide-based hydrogels form excellent scaffolds to allow for three-dimensional cell culture owing to the favorable properties such as capability to absorb large amount of water when immersed in biological fluids, ability to form “smart hydrogels” by being shear-thinning and thixotropic, and eliciting minimum immunological response from the host. In this study, the biodegradable shear-thinning polysaccharide, gellan-gum based hydrogel was investigated for the conditions and concentrations in which it can be applied for the adhesion, propagation and assembly of different mammalian …

Humidity Effect On The Structure Of Electrospun Core-Shell Pcl-Peg Fibers For Tissue Regeneration Applications, Adam P. Golin

Electronic Thesis and Dissertation Repository

With the aim of creating a biodegradable scaffold for tympanic membrane (TM) tissue regeneration, core-shell nanofibers composed of a poly(caprolactone) shell and a poly(ethylene glycol) core were created using a coaxial electrospinning technique. In order to create fibers with an optimal core-shell morphology, the effect of relative humidity (RH) on the core-shell nanofibers was systematically studied, with a FITC-BSA complex encapsulated in the core to act as a model protein. The core-shell nanofibers were electrospun at relative humidity values of 20, 25, 30, and 40% RH within a glove box outfitted for humidity control. The core-shell morphology of the fibers …

Design Of Controlled Environment For Tissue Engineering, Malcolm Gerald Lapera

Master's Theses

Design of Controlled Environment for Tissue Engineering

Malcolm Lapera

Tissue engineering aims at relieving the need for donor tissue and organs by developing a process of creating viable tissues in the laboratory setting. With over 120,000 people awaiting a transplant, the need for generating tissue engineered organs is very large [3]. In order for organs to be engineered, a few issues need to be overcome. A work space that both creates an environment which maintains cell viability over an extended period of time as well as accommodates the necessary fabrication equipment will be needed to further tissue engineering research. Therefore, …