Biomedical Engineering and Bioengineering Commons^™

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 …

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 …

Superelastic And Ph-Responsive Degradable Dendrimer Cryogels Prepared By Cryo-Aza-Michael Addition Reaction, Juan Wang, Hu Yang

Chemical and Biochemical Engineering Faculty Research & Creative Works

Dendrimers exhibit super atomistic features by virtue of their well-defined discrete quantized nanoscale structures. Here, we show that hyperbranched amine-terminated polyamidoamine (PAMAM) dendrimer G4.0 reacts with linear polyethylene glycol (PEG) diacrylate (575 g/mol) via the aza-Michael addition reaction at a subzero temperature (-20 °C), namely cryo-aza-Michael addition, to form a macroporous superelastic network, i.e., dendrimer cryogel. Dendrimer cryogels exhibit biologically relevant Young's modulus, high compression elasticity and super resilience at ambient temperature. Furthermore, the dendrimer cryogels exhibit excellent rebound performance and do not show significant stress relaxation under cyclic deformation over a wide temperature range (-80 to 100 °C). The …

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 …

Using Crosslinked Hyaluronic Acid (Ha) And Collagen Scaffolds With Sustained Brain-Derived Neurotrophic Factor (Bdnf) Release For Post-Sci Nerve Regeneration, Panth Doshi

UROP Posters

Traumatic events resulting in spinal cord injuries (SCIs) often leave people paralyzed or with partial loss of motor function. The physical disabilities arising from traumatic events prevent people from functioning at the same level as pre-injury. My work aims to identify a plausible method to overcome the inhibitory post-SCI environment and to regenerate nervous tissue in order to restore neural function and, subsequently, motor function. I identified components of a new, hypothetical nerve scaffold based on the immune response after SCIs and the efficacy of currently used scaffolds for nerve regeneration. Hyaluronic acid (HA) polymer scaffolds and collagen-based scaffolds are …

Naturally-Derived Extracellular Matrix Materials For Meniscus Repair And Regeneration, Jinglei Wu

Bioengineering Dissertations - Archive

Human meniscus plays critical roles in a knee joint by transmitting weight-bearing force, absorbing shock, and stabilizing the knee joint capsule. Meniscal injuries are mainly caused by sports-related activities and age-related degeneration, which significantly reduce the life quality of patients. The injured meniscus has a very limited self-healing capability due to its poorly vascularized nature, specifically in the inner area. Surgical interventions are required to treat the injured meniscus, but the current treatments are not satisfactory because the post-surgery complications are frequently observed. Therefore, tissue regeneration approaches are developed to repair and functionally restore injured menisci. In this thesis, we …

Ultrasonically Responsive Tissue Engineering Scaffolds For The Temporal Control Over Osteo-Inductive Growth Factor Delivery, Catherine Linh

Senior Honors Projects

In 2012, approximately 6.8 million people in the United States were diagnosed with orthopedic injuries or diseases. Over 500,000 people in the United States underwent bone grafting procedures, which cost 2.5 billion dollars per year and can result in complications. Polymer-based grafting scaffolds can facilitate 3D bone tissue growth in a localized, sustained manner. However, bone regeneration requires the orchestration of a sequence of events. Current scaffolds based on degradation and diffusion cannot provide sequential deliveries. We aimed to design a polymer scaffold that can release one payload diffusively at early time points, followed by ultrasonically triggered release of a …

Alginate Hydrogels As Three-Dimensional Scaffolds For In Vitro Culture Models Of Growth Plate Cartilage Development And Porcine Embryo Elongation, Taylor D. Laughlin

Department of Agricultural and Biological Systems Engineering: Dissertations, Theses, and Student Research

The establishment of in vitro culture models utilizes tissue engineering principles to design functional mimics of in vivo environments in vitro. Advantages for the use of in vitro culture models include ethical alleviation of animal models for therapeutic testing, cost efficiency, and a greater ability to study specific mechanisms via a systematic, ground-up approach to development. In this thesis, alginate hydrogels are utilized in the development of in vitro culture models of porcine embryo elongation and growth plate cartilage development. First, the effect of scaffold and modifications to the scaffold were explored in both projects. In order to modulate …

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 …

Bioengineering In Vitro Human Trabecular Meshwork Models For Glaucoma Therapeutic Screening, Karen Yud Torrejon

Legacy Theses & Dissertations (2009 - 2024)

Glaucoma refers to a group of slowly progressing eye disorders that lead to damage to the optic nerve, resulting in irreversible vision loss. Recent statistics by the World Health Organization places glaucoma as a leading cause of blindness worldwide, affecting nearly 80 million people. Lowering intraocular pressure (IOP) is currently the only effective target for therapeutic intervention in glaucoma. IOP is mostly controlled by the outflow of the aqueous humor (AH) through the trabecular meshwork (TM). The TM and adjacent endothelium of Schlemm’s canal, known as the conventional outflow-tract, control AH outflow and thus determine IOP.

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 …

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, …

Human Hair Keratin Protein, Hair Fibers And Hydroxyapatite (Ha) Composite Scaffold For Bone Tissue Regeneration, Samuel Siyum

ETD Archive

The field of tissue engineering aims at promoting the regeneration of tissues or replacement of failing or malfunctioning tissue by means of combining a scaffold material, adequate cells and bioactive molecules. Different materials have been proposed for use as three-dimensional porous scaffolds for bone tissue engineering procedures. Among them, polymers of natural origin are one of the most attractive options mainly due to their similarities with the extracellular matrix (ECM), chemical versatility as well as typically good biological performance. In this study, two biocompatible composite scaffolds were developed from natural polymer by tissue engineering approach and tested in vitro. The …

Investigating The Reproducibility Of The Current Bvm Protocol, Corey Gross

Biomedical Engineering

Coronary Artery Disease (CAD) is responsible for 1 death every minute in the US. Angioplasty with the implantation of stents is a common treatment method for CAD. Although there is a variety of stents currently on the market, there is still a need to develop new types for different pathologic conditions. Preliminary assessment of the physiological response to new stents is needed as they are being developed. The FDA approval process implemented today is a long, tedious path with a range of testing methods that include static in vitro testing and high-cost animal testing. Tissue engineered blood vessels have been …

Integrated Fiber Electrospinning: Creating Spatially Complex Electrospun Scaffolds With Minimal Delamination, Casey Grey

Theses and Dissertations

Tissue engineering scaffolds come in many shapes and sizes, however, due to difficulty manufacturing the microstructure architecture required in tissue engineering, most scaffolds are architecturally non-dynamic in nature. Because the microstructural architecture of all biological tissues is inherently complicated, non-dynamic tissue engineering scaffolds tend to be a poor platform for tissue regeneration. The current method for manufacturing dynamic tissue engineering scaffolds involves electrospinning successive layers of different fibers, an approach that exhibits no fiber transition between layers and subsequent delamination problems. In this study we aim to address the design challenges of tissue engineering scaffolds through our novel integrated fiber …

Preparation And Characterization Of A Self-Crimp Side-By-Side Bicomponent Electrospun Material, Yang Han

Theses and Dissertations

Bicomponent composite fibers have been widely used in the textile industry and are gaining increasing attention on biomedical applications. In this research, polycaprolactone/poly (lactic acid) side-by-side bicomponent fibers were created for the application of a biodegradable scaffold. The side-by-side structure endowed the fiber with self-crimps when it was processed under certain conditions. This material was produced by electrospinning and collected on a high speed rotating mandrel to get highly oriented fibers. A mechanical stretch at the same direction was done followed by a wet heat treatment for polymer retraction. Crimped fibers were demonstrated by scanning electron microscopy. The quantitative porosity …

Tissue Engineering A Blood Vessel Mimic While Monitoring Contamination Through Sterility Assurance Testing, Navid Djassemi

Master's Theses

Tissue Engineering A Blood Vessel Mimic While Monitoring Contamination Through Sterility Assurance Testing

Navid Djassemi

Tissue engineering blood vessel mimics has been proposed as a method to analyze the endothelial cell response to intravascular devices that are used in today’s clinical settings for the treatment of cardiovascular disease. Thus, the development of in vitro blood vessel mimics (BVMs) in Cal Poly’s Tissue Engineering Lab has introduced the possibility of assessing the characteristics of cellular response to past, present, and future intravascular devices that aim at treating coronary artery disease.

This thesis aimed at improving the methods and procedures utilized in …

Development And Characterization Of An In-House Custom Bioreactor For The Cultivation Of A Tissue Engineered Blood-Brain Barrier, Amin Hadi Mirzaaghaeian

Master's Theses

The development of treatments for neurological disorders such as Alzheimer’s and Parkinson’s disease begins by understanding what these diseases affect and the consequences of further manifestation. One particular region where these diseases can produce substantial problems is the blood-brain barrier (BBB). The BBB is the selective diffusion barrier between the circulating blood and the brain. The barrier’s main function is to maintain CNS homeostasis and protect the brain from the extracellular environment. The progression of BBB research has advanced to the point where many have modeled the BBB in vitro with aims of further characterizing and testing the barrier. Particularly, …

Development And Characterization Of Plga And Eptfe Blood Vessel Mimics Using Gene Expression Analysis, Michael Gibbons, Sarah Ur

Biomedical Engineering

Tissue engineered blood vessels (TEBV’s) have the potential to act not only as a replacement for diseased vessels, but also as a testing platform for intravascular devices such as stents. To this end, the goal of this study was to develop protocols for the construction of TEBV’s composed of human vascular cells and either expanded polytetrafluoroethylene (ePTFE) or poly-lactic-co-glycolic acid (PLGA), as well as a protocol for gene expression in those TEBV’s. Initial experiments involved only human umbilical vein endothelial cells (HUVEC’s), but after low cell confluency and spreading in single-sodded vessels a second cell type, human umbilical vein smooth …

In Vivo Immunotoxicological Evaluation Of Electrospun Polycaprolactone (Epcl) And Investigation Of Epcl As A Drug Delivery System For Immunomodulatory Compounds, Colleen Mcloughlin

Theses and Dissertations

Electrospun materials have potential use in many biomedical applications such as soft tissue replacements or as scaffolds to target drug delivery to local sites. Electrospinning is a polymer processing technique that can be used to create materials composed of fibers with diameters ranging from the micron to the nanoscale. We investigated the effects of microfibrous and nanofibrous electrospun polycaprolactone (EPCL) on innate, cell-mediated, and humoral components of the immune system. Results demonstrated that in both young (12 week) and old (6 month) mice, EPCL had no effect on various immune parameters. With its lack of immunotoxicity, EPCL presents an excellent …

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 …

Magnetic Resonance Elastography Methodology For The Evaluation Of Tissue Engineered Construct Growth., Evan Curtis, Simeng Zhang, Vahid Khalilzad-Sharghi, Thomas Boulet, Shadi F. Othman

All Faculty Articles - School of Engineering and Computer Science

Traditional mechanical testing often results in the destruction of the sample, and in the case of long term tissue engineered construct studies, the use of destructive assessment is not acceptable. A proposed alternative is the use of an imaging process called magnetic resonance elastography. Elastography is a nondestructive method for determining the engineered outcome by measuring local mechanical property values (i.e., complex shear modulus), which are essential markers for identifying the structure and functionality of a tissue. As a noninvasive means for evaluation, the monitoring of engineered constructs with imaging modalities such as magnetic resonance imaging (MRI) has seen increasing …

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 …

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 …

Silk Fibroin-Based Scaffolds For Tissue Engineering Applications, Jennifer Mccool

Theses and Dissertations

This study focused on the comparison of the electrospun silk scaffolds to the electrospun silk fibroin gel scaffolds. Moreover, this study examined the differences in cross-linking effects of genipin and methanol as well as solvents on the mechanical properties and cell compatibility of the scaffolds. Silk scaffolds were electrospun from an aqueous solution or 1,1,1,3,3-hexafluoro-2-propanol (HFIP) without genipin, immediately after 8 % (wt) genipin was added to the solution, and 18 hours after genipin blended with the solution. Uniaxial tensile testing determined that the silk scaffolds electrospun from water exhibit a higher modulus and peak stress than that of the …

Characterization And Implementation Of A Decellularized Porcine Vessel As A Biologic Scaffold For A Blood Vessel Mimic, Aubrey N. Smith

Master's Theses

Every 34 seconds, someone in the United States suffers from a heart attack.  Most heart attacks are caused by atherosclerotic build up in the coronary arteries, occluding normal blood flow.  Balloon angioplasty procedures in combination with a metal stent often result in successful restoration of normal blood flow.  However, bare metal stents often lead to restenosis and other complications.  To compensate for this problem, industry has created drug-eluting stents to promote healing of the artery wall post stenting.  These stents are continually advancing toward better drug-eluting designs and methods, resulting in a need for fast and reliable pre-clinical testing modalities. …