Biomedical Engineering and Bioengineering Commons^™

Blow-Spun Hybrid Pcl-Peo/Hnts Scaffolds With Enhanced Biological And Mechanical Properties, Meichen Liu

Doctoral Dissertations

With the development of technology and engineering, nanotechnology has been a multidisciplinary scientific field applied in nearly all science areas, including medicine, genetics, food industry, robotics. In this respect, nanomedicine has gained increasing attention and been a useful, effective therapy for cancer diagnosis, gene transfer, and drug delivery. To design an ideal nano drug delivery system with controlled drug releasing and improved encapsulated drug’s pharmacokinetic and pharmacodynamic profiles, hydrogels and polymer composites have witnessed increased research interest during the last decades. Recently, numerous polymers have been studied to fabricate the ideal wound dressing with biocompatibility, biodegradability, porous structural, and suitable …

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 …

Angiogenic Supports For Microvascular Engineering, Zain Siddiqui

Dissertations

Ischemic tissue disease is caused by a lack of circulation / blood supply to tissue. This can be treated by introducing a number of angiogenic (pro-blood vessel forming) factors into the tissue. This work presents strategies for ischemic tissue treatment utilizing a novel proangiogenic self-assembling peptide hydrogel platform. To demonstrate the utility of this platform, its use alone as an angiogenic therapeutic (both alone as a self-assembling hydrogel and with two-component systems), and its ability to vascularize implants is explored. Due to these angiogenic scaffolds demonstrating efficacy to regenerate microvasculature, this work evaluates diseases that can be treated by the …

Enhancing Human Schwann Cells Reparative Behavior Using Heparin/Collagen Layer-By-Layer Coatings, Luis Carlos Pinzon-Herrera

Graduate Theses and Dissertations

When a peripheral nerve injury (PNI) occurs, the gold standard for tissue regeneration is the use of autografts. However, due to the secondary effects produced by multiple surgeries involved in the removal and implantation of autografts for very small lesions, it is possible to replace them with the use of Nerve Guide Conduits (NGCs). However, NGCs are limited to short lesions (less than 1 cm). This limitation is caused by the absence of compounds in the extracellular matrix (ECM) that autografts can provide. Since much of the regenerative process takes place on the NGC surface, our work aims to modify …

The Influence Of Processing And Additives On Cellulose Nanofiber Properties For Orthopedic Application, Mitchell P. Chesley

Electronic Theses and Dissertations

Current orthopedics are separated into three different classes of materials, metals, polymers, and ceramics. While these devices have had success throughout the years they are not without their faults. Metallic devices for example are usually extraordinarily stiff when compared with the surrounding bone. This difference in stiffness induces localized stress-shielding promoting cortical atrophy, which can lead to osteoporosis. Polymers while having the capacity of being biodegradable and bioabsorbable also have the potential to incite localized demineralization and weakness in surrounding bone. A result of breakdown byproducts not efficiently being evacuated from the area, which additionally acts as catalysts expediating the …

Effects Of Surface Topography On Macrophages And Bacterial Cells, Joseph Carnicelli

Theses - ALL

An association has been found between the texture of breast implants and anaplastic large cell lymphoma, which led to some textured implants to be withdrawn from the market in 2019. There is evidence that these cancers are associated with the harboring of bacteria on the surfaces of the textured implants. It is possible that specific topographic features hinder the removal of attached bacteria by inhibiting macrophage phagocytosis or promoting biofilm formation. Here we examine how bacteria and macrophages interact with recessive surface topographies as analogs to the surfaces seen on textured breast implants. Changes in bacteria morphology were observed among …

Development Of Brain-Derived Bioscaffolds For Neural Progenitor Cell Culture And Delivery, Julia Terek

Electronic Thesis and Dissertation Repository

The use of brain extracellular matrix (ECM) as a biomaterial has the potential to promote neural tissue regeneration by providing cell-instructive cues that direct survival, proliferation, and differentiation. This study developed a novel detergent-free decellularization protocol that effectively reduced cellular content while preserving key ECM components in porcine and rat brains. The resulting decellularized brain tissue (DBT) was incorporated into microcarriers to assess its effects on the growth, phenotype and neurotrophic factor gene expression of rat brain-derived progenitor cells cultured within spinner flask bioreactors, using purified collagen microcarriers as a control. Both types of microcarriers supported cell expansion and survival, …

Combinatorial Approaches For Effective Design, Synthesis, And Optimization Of Enzyme-Based Conjugates, Jordan Scott Chapman

Graduate Theses, Dissertations, and Problem Reports

The specificity and efficiency with which enzymes catalyze selective chemical reactions far exceeds the performance of traditional heterogeneous catalysts that are predominant in industrial applications such as conversion of commodity chemicals to value-added products, fuel cells, and petroleum refinement. Moreover, biocatalysts exhibit exceptionally high product turnover at ambient conditions with little health and environmental burden. These advantageous qualities have led to the prolific use of enzyme catalysis in pharmaceutical, detergents, and food preservation industries wherein their use has greatly reduced waste generation, Unfortunately, the full slate of benefits that enzymes can impart to a broader range of chemical processes is …

Development Of Multifunctional Drug Delivery Systems For Locoregional Therapy, Xinyi Li

Electronic Thesis and Dissertation Repository

Locoregional treatment is the specific delivery of therapeutics to their desired sites of action with minimized systemic adverse effects. In this approach, drug is administered through topical instillation, inhalation, intra-lesional or intra-arterial injection. Decades of experience in locoregional treatment have delivered meaningful benefits to patients with localized diseases (e.g., osteoarthritis, ocular disorders and liver cancers). However, improvements are required for this type of treatment to be more effective. For transarterial chemoembolization (TACE) therapy of hepatocellular carcinoma (HCC), the most current approaches do not allow repeat treatment as the drug delivery vehicle is not degradable. In addition, image contrast agents for …

Synthesis And Performance Testing Of Ecm Fiber Scaffolds, Cassandra Reed

Graduate Theses and Dissertations

The progression of regenerative medicine has advanced the treatment of multiple illnesses and injuries throughout the years. A good example of the benefits of this research is the work that has gone into volumetric muscle loss (VML), where more than 20% of the muscle is loss. Skeletal muscle makes up 40% of the human body so a loss of that size greatly diminishes the strength, the flexibility, physiology, and quality of life of the injured individual. For that reason, various techniques are used to counteract the loss of structure and innate cellular signaling in order to circumvent that from happening. …

Laminin-Mimetic Peptide-Functionalized Hydrogel Systems For The Phenotypic Modulation Of Cells Of The Nucleus Pulposus, Marcos Nicolas Barcellona

McKelvey School of Engineering Theses & Dissertations

The intervertebral disc (IVD) has been widely observed to undergo significant structural and biochemical changes with age and maturation. As degeneration progresses, changes in extracellular matrix composition and deposition, tissue cellularity, and metabolic activity have been characterized. Although the epidemiology of disc degeneration remains unclear, it is believed that the nucleus pulposus (NP) region of the IVD may be implicated in early degeneration. Specifically, cells of the nucleus pulposus have been observed to undergo a shift from their notochordal-like juvenile phenotype to a more fibroblast-like state in a manner concomitant to degenerative events. Because the disc has inherently little capacity …

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 …

Effects Of Genipin Crosslinking On The Properties Of Tendon Derived Extracellular Matrix Hydrogels, Alicia Cheyenne Coombs

Theses and Dissertations

Extracellular matrix (ECM) hydrogels are a useful biomaterial in the tissue engineering field used for injectables in drug delivery systems, wound dressing, tissue regeneration and many other applications. ECM hydrogels are highly biocompatible, contain proper ratios of biomolecules required for complex bioactivity of tissues and they promote tissue repair. However, ECM hydrogels typically have poor mechanical strength, which leads to hydrogel instability, and a limitation in their ability to be modified for translational applications. In this research, genipin, a natural crosslinker derived from plants, was utilized in an attempt to improve upon the mechanical limitations of ECM hydrogels. Genipin has …

Bioink Optimization And Effects Of Microgravity On 3d Bioprinted Cell Laden Constructs, Likitha Somasekhar

Theses and Dissertations

Bioengineered 3D tissue constructs have gained attention as in vitro tools for the study of cell-cell and cell-matrix interactions and are being explored for potential use as experimental models for mimicking human tissues. One of the main problems in tissue engineering is the necessity to vascularize complex engineered tissues and sacrificial printing has been recognized as a possible solution to vascularization of the bioprinted tissues. Research studies have demonstrated that exposure to microgravity in space induces adaptive alterations in vascular structure and function. Changes in the morphology and gene expression is observed when endothelial cells are exposed to microgravity and …

Immunomodulatory Biomaterials For Cancer Immunotherapy, Larry Donnell Stokes Jr

Honors Theses

Cancer immunotherapy has become an effective treatment in the toolbox of oncologists. Immunotherapy offers a less toxic alternative to standard cancer treatments such as chemotherapy and can have prolonged curative effects to decrease cancer recurrence. Today, many drugs and biological agents have been developed that target the immune system and elicit an antitumor/cancer response. These agents are known collectively as cancer immunotherapies. While immunotherapies have radically improved treatment outcomes for many cancer patients, there are drawbacks to using these treatments. Immunotherapy treatments have poor clinical responses in patients with tumors that lack immunogenicity. Some of the treatments also pose a …

Promotion Of Human Schwann Cell Proliferation Using Heparin/Collagen Coated Nerve Conduits, John Magness

Chemical Engineering Undergraduate Honors Theses

Often in the aftermath of an injury or surgery, the sense of touch and muscle control is lost in the affected area as nerves are damaged or severed and fail to grow back completely. The regeneration of the nerve cells can be promoted by treating the nerves with nerve conduits. Nerve conduits are hollow cylinders of bio-compatible materials that can be surgically implanted to the disconnected nerve to promote and direct the growth of nerves. The objectives of this research are to investigate the ability of nerve conduits treated with layer-by-layer coatings to promote the growth of Schwann cells, to …

Injectable Gelatin-Silk Fibroin Composite Hydrogels For In Situ Cell Encapsulation, Ryann D. Boudreau

Honors Theses and Capstones

Hydrogels are widely used tools for tissue engineering and regenerative medicine. Characterized as biofunctional, water-based polymer matrices with tunable mechanical properties, hydrogels have promising but limited applications in biomedical engineering, due to poor and static matrix strength. Here we plan to rectify this issue by introducing a new hydrogel made from a composite of gelatin and silk fibroin crosslinked by microbial transglutaminase (mTG) instantly and beta sheet formation gradually, respectively. This interpenetrating network (IPN) shows enhanced mechanical stiffness and strength compared to gelatin hydrogels, and is capable of encapsulating human cells with high viability demonstrated by the encapsulation of human …

Nature-Inspired Material Strategies Towards Functional Devices, Sayantan Pradhan

Theses and Dissertations

Naturally sourced, renewable biomaterials possess outstanding advantages for a multitude of biomedical applications owing to their biodegradability, biocompatibility, and excellent mechanical properties. Of interest in this dissertation are silk (protein) and chitin (polysaccharide) biopolymers for the fabrication of functional biodevices. One of the major challenges restricting these materials beyond their traditional usage as passive substrate materials is the ability to combine them with high-resolution fabrication techniques. Initial research work is directed towards the fabrication of micropatterned, flexible 2D substrates of silk fibroin and chitin using bench-top photolithographic techniques. Research is focused on imparting electrochemical properties to silk proteins using conducting …

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 …

Carbon Nanotube-Coated Scaffolds For Tissue Engineering Applications, Soham Dipakbhai Parikh

Browse all Theses and Dissertations

Carbon Nanotubes (CNTs) have beneficial properties for cell scaffolding, which has translated into effective growth of bone, muscle, and cardiac cells. However, loose carbon nanotubes can cause in vivo toxicity. To reduce this risk, our team has developed biomimetic scaffolds with multiscale hierarchy where carpet-like CNT arrays are covalently bonded to larger biocompatible substrates. In this study, we have tested such scaffolds in two distinct types of biomedical applications involving glioblastoma and keratinocyte cells. The growth of glioblastoma (GBM) cells on our CNT-coated biomimetic scaffolds was evaluated to check their suitability as a potential chemotherapy-loaded implant for GBM patient treatment. …

Engineering Stimuli-Responsive Polymeric Nanoassemblies: Rational Designs For Intracellular Delivery Of Biologics, Kingshuk Dutta

Doctoral Dissertations

Biologic drugs have gained enormous research attention in recent years as reflected by the development of multiple candidates to the clinical pipelines and an increased percentage of FDA approval. This is reasoned by the fact that biologics have been proven to deliver more predictive and promising benefits for many hard-to-cure diseases by ‘drugging the undruggable’ targets. However, the challenges associated with biologic drug development are multi-fold, viz, poor encapsulation efficacy, systemic instability, low cellular internalization and endosomal escape capability. Thus, it is essential to develop new molecular strategies that can not only address the associated drug delivery challenges, but also …

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 …

3-D Silk Fibroin Porous Particles Created By The Ouzo Effect For Biomedical Applications, Ashley Nicole Lamb

UNLV Theses, Dissertations, Professional Papers, and Capstones

Due to its high biocompatibility and biodegradability, silk fibroin – produced from

Bombyx mori (B. mori) cocoons – has been at the forefront of research for many

biomedical application formats: hydrogels, films, microspheres, and porous

sponges/scaffolding, to name a few. For drug delivery, in particular, porous particles are

desirable for their large surface area, uniform and tunable pore structure, and high

porosity. This thesis focuses on the fabrication of porous particles from silk fibroin by the

very interesting Ouzo effect. The Ouzo effect, so named because of the Greek

beverage ouzo, describes the phenomenon of an ethanol + anethole oil …

Ph-Sensitive Oxygen Release Microspheres To Enhance Cell Survival In Ischemic Condition, Zhongting Liu

McKelvey School of Engineering Theses & Dissertations

Ischemic diseases such as myocardial infarction, stroke and limb ischemia are severe cardiovascular diseases with high rate of death and millions of people suffered from these diseases. Under ischemic environment, cells die due to deficient supply of nutrient and oxygen. To regenerate ischemic tissues, stem cell therapy is a promising approach because stem cells can differentiate into cells necessary for the regeneration. However, stem cell therapy has limitations. For example, few cells can survive under harsh ischemic environment. To enhance stem cells survival, implantation of oxygen release microspheres to sustained supply cells with oxygen represents an effective strategy. Previously, our …

The Co-Delivery Of Syngeneic Adipose-Derived Stromal Cells And Macrophages On Decellularized Adipose Tissue Bioscaffolds For In Vivo Soft Tissue Regeneration, Hisham A. Kamoun

Electronic Thesis and Dissertation Repository

Decellularized adipose tissue (DAT) bioscaffolds are a promising platform for the delivery of pro-regenerative cell populations with the goal of promoting adipose tissue regeneration. The current study investigated the effects of seeding DAT bioscaffolds with syngeneic bone marrow-derived macrophages and/or adipose-derived stromal cells (ASCs) on in vivo soft tissue regeneration. Methods were established to derive the macrophages from MacGreen mice, which were dynamically seeded onto the DAT scaffolds alone or in combination with ASCs. Seeded and unseeded scaffolds were implanted subcutaneously into C57Bl/6 mice. At 2 and 4 weeks, cell infiltration, angiogenesis, and adipogenesis were analyzed through histology and immunohistochemistry. …

Application Of Halloysite Nanotubes In Bone Disease Remediation And Bone Regeneration, Yangyang Luo

Doctoral Dissertations

Customized patient therapy has been a major research focus in recent years. There are two research fields that have made a significant contribution to realizing individualized-based treatment: targeted drug delivery and three-dimensional (3D) printing technology. With benefit from the advances in nanotechnology and biomaterial science, various drug delivery systems have been established to provide precise control of therapeutic agents release in time and space. The emergence of three-dimensional (3D) printing technology enables the fabrication of complicated structures that effectively mimic native tissues and makes it possible to print patient-specific implants. My dissertation research used a clay nanoparticle, halloysite, to develop …

Characterization Of Nano-Cellulose Based Composites For Biomedical Applications, Mitchell P. Chesley

Electronic Theses and Dissertations

The number of orthopedic surgeries performed globally has steadily increased over the past decade due to the standardization of procedures as well as technological advancements. During this time orthopedic devices have been composed predominantly of metals, such as Titanium, Vanadium, Molybdenum, and Stainless steel, as well as their alloys, due to the high strength and durability of these materials. However, metals may, in fact, be suboptimal for orthopedic devices. For example, metals exhibit Young’s modulus much greater than the surrounding bone, inducing localized stress-shielding promoting cortical atrophy, which can lead to osteoporosis. In recent years polymers have been successfully explored …

Design, Construction And Application Of A Home-Built, Two-Photon Microscope, William P. Breeding

Electronic Theses and Dissertations

Two-photon microscopy (TPM) is a powerful, versatile imaging modality for the study of biological systems. This thesis overviews the relevant physics involved in TPM, design considerations and process of constructing a home-built, two-photon microscope, and provides a set of procedures to operate the system. Furthermore, this work explores several applications of TPM through the study of single-cell metabolism and imaging the cellular-material interface. Explored in particular depth was the imaging of cellulose nanofiber (CNF) materials, with the goal of understanding the three-dimensional nature of fibroblast cell growth when embedded within the materials. This work uncovered several optical properties of CNF, …

Investigation Of The Effect Of Age On Regenerative Outcomes Following Treatment Of Volumetric Muscle Loss Injuries, John Taehwan Kim

Graduate Theses and Dissertations

Volumetric muscle loss (VML) is a traumatic injury in skeletal muscle resulting in the bulk loss of more than 20% of the muscle’s volume. Included in the bulk loss of muscle is the skeletal muscle niche comprised of nerve bundles, vasculature, local progenitor cells, basal lamina, and muscle fibers, overwhelming innate repair mechanisms. The hallmark of VML injury is the excessive accumulation of non-contractile, fibrotic tissue and permanent functional deficits. Though predominant in the younger demographic, the elderly population is also captured within VML injuries. There are many factors that change with aging in skeletal muscle that may further hinder …

Two And Three-Dimensional Models For Material And Cells Interaction, Nam H. Nguyen

Doctoral Dissertations

Three-dimensional (3D) cell spheroid model has been long considered a better model to mimic in vivo physiology compared to two-dimensional (2D) cell culture model. Traditional 2D cell models provide a simple, convenient and quick technique for drug screening but fail to simulate the complexity and heterogeneity of cells in the in vivo environment. The last few decades have remarked substantial progress toward the advancement of three-dimensional (3D) cell cultures as systems which better mimic cellcell and cell-matrix interaction in the in vivo physiology. Nowadays, 3D cell models have been emerging, not only as an important approach in drug discovery and …