Biomedical Engineering and Bioengineering Commons^™

Corrosion Characteristics Of Magnesium Under Varying Surface Roughness Conditions, Yahya Efe Yayoglu

USF Tampa Graduate Theses and Dissertations

The biggest challenge with magnesium alloy biodegradable implants is the rapid corrosion at the earlier stages of the healing process after implantation. In this research, the impact of surface roughness generated by different means on the corrosion rate of AZ31 magnesium alloy in a simulated biologic environment is investigated. In order to perform accurate experimentation, an in vitro setup is assembled that simulates the human body environment accurately has been prepared using Schinhammer’s in vitro immersion testing setup and Kokubo’s Simulated Body Fluid (SBF). For the immersion test of Mg in SBF, several surface texture groups of Mg have been …

Synthesis, Characterization, And Application Of Monosized Mesoporous Silica Nanoparticle-Supported Lipid Bilayers For Targeted Therapeutic Delivery To Individual Cells, Paul Durfee

Biomedical Engineering ETDs

Mesoporous silica nanoparticle (MSNP) supported-lipid bilayers, termed ‘protocells,’ represent a potentially transformative class of therapeutic and theranostic delivery vehicles. The field of targeted drug delivery poses considerable challenges that cannot be addressed with a single ‘magic bullet’. Consequently, the protocell has been designed as a modular platform composed of interchangeable biocompatible components. The mesoporous silica core can have variable size and shape to direct biodistribution and controlled pore size and surface chemistry to accommodate diverse cargos. The encapsulating supported lipid bilayer can be modified with targeting and trafficking ligands as well as polyethylene glycol (PEG) to effect selective binding, endosomal …

Biomarker Detection At Risk Forecasting Level Using Metal-Enhanced Fluorescence Combined With Surface Acoustic Wave, Jun Liu

USF Tampa Graduate Theses and Dissertations

In this paper, metal-enhanced fluorescence (MEF) technique is used to lower the detection limit of carcinoembryonic antigen (CEA) which is able to be utilized in forecasting the risk of having certain kinds of cancers, especially colon and rectal cancer. By incubating silver nanocubes (Ag NCs) on the surface of the chips, the detection limit goes down to below 1ng/mL of CEA. Also, when combining MEF with surface acoustic wave (SAW) devices, the incubation time between antigen and antibody will decrease significantly with the fluorescence signal keeping similar or higher level.

Fluorescent Materials Design At Nanoscale For Biomedical Photonics In Near Infrared Window, Kohei Soga, Masao Kamimura

The 8th International Conference on Physical and Numerical Simulation of Materials Processing

No abstract provided.

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 …

Customization Of Titanate Nanofiber Bioscaffolds, Jared Hopkins

Biomedical Engineering Undergraduate Honors Theses

In the field of orthopedic devices implant loosening is a major issue resulting in the majority of device failures. These failures result in the need for costly secondary procedures. To reduce device loosening an improved method of tissue anchoring is required. A previously studied titanate nanofiber bioscaffold has been shown to be safely implantable and to contribute to the differentiation of mesenchymal stem cells to osteocytes. Through the customization of both physical and chemical characteristics this titanate nanofiber bioscaffold was fabricated as a potential means to enhance tissue anchoring for use with orthopedic devices. This customization was enabled by acoustic …

A Numerical Approach To Investigate The Influence Of Deformable Blockages On Blood Flow In An Elastic Vessel, Tai-Hsien Wu

Research and Creative Activities Poster Day

In this work, we presented a new numerical approach to study the deformation of blockages and fluid properties in an elastic blood vessel. In computational hemodynamics, only few of the current numerical models considered the elasticity of vessels, and those models were difficult to extend to other topics like the deformation of blockages in elastic blood vessels. In addition, the approach that we employed is especially effective on visualization. A validation for the present method is carried out by comparing the simulation results with a theoretical prediction of the deformation of the pulmonary blood vessel in a steady flow. Subsequently, …

Molecular Combing Of Dna Nanofibers And Comparison To Electrospinning, Tanner L. Buresh

UCARE: Research Products

The goal of these experiments was to create DNA nanofibers through the method of molecular combing (MC) and then compare the MC fibers to fibers created with electrospinning (ES). The experiment was designed and initial samples were created. After confirming that the method would succeed in creating DNA fibers, several parametric studies were performed in order to optimize the experiment and create the most uniform fibers possible. The parametric studies were done on the following variables: substrate material, pH level of DNA solution, and DNA solution concentration. After completion of all experiments, it was determined that although fibers could be …

Dendrimer Nanoconjugates And Their Oral Inhalation Formulations For Lung Cancer Therapy, Qian Zhong

Wayne State University Dissertations

Lung cancers are leading cause of cancer death for both men and women in the world. Lungs are also one of the primary organs to which almost all cancer can spread. Chemothepray plays a crucial role in the fight against both primary lung cancers and lung metastases. Doxorubicin (DOX) is a potent anticancer drug that has been approved for treating many cancers including lung cancers. However, only a few percent of systemically administered DOX can be found in the lungs. The issue is further complicated by dose-limiting toxicity of DOX. Another major challenge in the use of DOX is its …

Enhancement Of Cancer Vaccine Efficacy Via Nanoparticle Or Molecular-Based Adjuvants, Myunggi An

Wayne State University Theses

Adjuvants are immunomodulators which enhance immune responses to vaccines. However, parenteral administration of unformulated adjuvants fails to reach lymph nodes (LNs), the anatomic organ where the primary functions of immune cells are orchestrated. The LN-targeting delivery plays the key roles in promoting immune activation and has the great potential to transform disease treatment. The main goal of this thesis is to develop efficient vaccine delivery systems to target therapeutics into draining lymph nodes (dLNs) for ensuring their immunostimulatory activity. We introduced therapeutic applications of activating TLR9 with synthetic CpG oligodeoxynucleotide (ODN) agonists in nanoparticle or molecular form to activate immune …

Effects Of Antidepressants On Human Mesenchymal Stem Cell Differentiation On Clinically Relevant Titanium Surfaces, Nancy B. Ayad

Theses and Dissertations

Selective Serotonin Reuptake Inhibitors (SSRIs) are the most frequently prescribed class of drugs worldwide and are implemented in the treatment of depression and other psychiatric disorders. SSRIs relieve depressive symptoms by modulating levels of the neurotransmitter serotonin in the brain. SSRIs block the function of the serotonin transporter, thereby increasing concentrations of extracellular serotonin. However, serotonin levels in the neurons of the brain only account for 5% while the remaining 95% is present outside the brain. Serotonin receptors and transporter are located on bone resident cells (mesenchymal stem cells (MSCs)), osteoblasts and osteoclasts, and serotonergic activity is believed to affect …

Bioactive Poly(Beta-Amino Ester) Biomaterials For Treatment Of Infection And Oxidative Stress, Andrew L. Lakes

Theses and Dissertations--Chemical and Materials Engineering

Polymers have deep roots as drug delivery tools, and are widely used in clinical to private settings. Currently, however, numerous traditional therapies exist which may be improved through use of polymeric biomaterials. Through our work with infectious and oxidative stress disease prevention and treatment, we aimed to develop application driven, enhanced therapies utilizing new classes of polymers synthesized in-house. Applying biodegradable poly(β-amino ester) (PBAE) polymers, covalent-addition of bioactive substrates to these PBAEs avoided certain pitfalls of free-loaded and non-degradable drug delivery systems. Further, through variation of polymer ingredients and conditions, we were able to tune degradation rates, release profiles, cellular …

Biodegradable Electronic And Optical Devices Toward Temporary Implants, Md Shihab Adnan

Masters Theses

"Implantable biomedical devices have a high potential to revolutionize health care technologies in near future. Implantable devices can be classified as permanent prosthetic devices such as pacemakers or nerve stimulants and temporary devices for intermediate monitoring and control scenario which are still in research phase. In contrast to permanent device, temporary implants lose functionality and become unnecessary after intended operational lifetime which may pose serious electromagnetic and biomedical safety concern, latent complications at the implanted sites and possible ethical issues if not removed from body by an additional surgical operation.

The first paper of this thesis focuses on exploring the …

Inhibition Of Bacterial Growth And Prevention Of Bacterial Adhesion With Localized Nitric Oxide Delivery, Julia Osborne

Dissertations, Master's Theses and Master's Reports

Bacterial infections continue to be a problem at the site of an indwelling medical device, and over the years, various bacterial strains have become more resistant to current antibiotic treatments. Bacterial infection at an indwelling medical device can be dangerous and affect the performance of the medical device which can ultimately lead to the failure of the device due to bacterial resistance to treatment.

Nitric Oxide (NO) has been shown to possess antibacterial properties to prevent and inhibit bacterial growth. NO releasing coatings on indwelling medical devices could provide a reduction in bacterial infections that occur at the device site …

Incorporation Of Fibrin Into A Collagen–Glycosaminoglycan Matrix Results In A Scaffold With Improved Mechanical Properties And Enhanced Capacity To Resist Cell-Mediated Contraction, Claire Brougham, Tanya J. Levingstone, Stefan Jockenhoevel, Thomas C. Flanagan, Fergal J. O'Brien

Articles

Fibrin has many uses as a tissue engineering scaffold, however many in vivo studies have shown a reduction in function resulting from the susceptibility of fibrin to cell-mediated contraction. The overall aim of the present study was to develop and characterise a reinforced natural scaffold using fibrin, collagen and glycosaminoglycan (FCG), and to examine the cell-mediated contraction of this scaffold in comparison to fibrin gels. Through the use of an injection loading technique, a homogenous FCG scaffold was developed. Mechanical testing showed a sixfold increase in compressive modulus and a thirtyfold increase in tensile modulus of fibrin when reinforced with …

The Role Of Biological Fluid And Dynamic Flow In The Behavior And Cellular Interactions Of Gold Nanoparticles, Emily K. Breitner, Saber M. Hussain, Kristen K. Comfort

Chemical and Materials Engineering Faculty Publications

Background: Due to their distinctive physicochemical properties, nanoparticles (NPs) have proven to be extremely advantageous for product and application development, but are also capable of inducing detrimental outcomes in biological systems. Standard in vitro methodologies are currently the primary means for evaluating NP safety, as vast quantities of particles exist that require appraisal. However, cell-based models are plagued by the fact that they are not representative of complex physiological systems. The need for a more accurate exposure model is highlighted by the fact that NP behavior and subsequent bioresponses are highly dependent upon their surroundings. Therefore, standard in vitro models …

Simulating Low-Frequency Sonic Pulsations To Achieve Thrombolysis, Joseph C. Muskat, Matthew C. Pharris, Charles F. Babbs

The Summer Undergraduate Research Fellowship (SURF) Symposium

Cardiovascular thrombosis may result in critical ischemia to a range of anatomical regions, constituting a leading cause of death in the United States. Current invasive treatments for such arterial blockages often yield blood clot recurrence, resulting in repeated hospitalization of patients. This research aims to show how internally introduced pressure oscillations may be used to initiate thrombolysis. We present a novel computational model for determining the resonant frequency and corresponding deformation of an idealized thrombus. Sinusoidal pressure differences across the thrombus induce axial displacements of frequency dependent amplitude. The maximum peak displacement occurs at a resonant frequency of 73 Hz …

Adsorption Mechanisms Of Palladium On The Tobacco Mosaic Virus Surface, Gloriia D. Novikova, Oluwamayowa Adigun, Erin Retzlaff-Roberts, Michael T. Harris

The Summer Undergraduate Research Fellowship (SURF) Symposium

Organic-inorganic materials synthesis using biological templates has recently drawn immense attention of researchers. Biotemplating has shown to be an efficient and economic means of nanomaterials production. Naturally stable, readily available and genetically malleable, Tobacco Mosaic Virus (TMV) is one of the most extensively studied and characterized biotemplates. Particularly, templated synthesis using TMV has produced high quality nanorods and nanowires that have been applied to batteries, memory devices and catalysis. The fundamental mechanisms, governing the adsorption of palladium on the TMV Wild Type and genetically modified versions (TMV1Cys and TMV2Cys), are not fully understood; this knowledge, however, is essential for future …

Molecular Dynamics Investigation Of The Arabinan-Cellulose Interface For Cellulose Nanocomposite Applications, Luke Thornley

Materials Engineering

Atom level computer simulations of the arabinan and cellulose interface were performed to better understand the mechanisms that give arabinan-cellulose composites (ArCCs) their strength with the goal to improve man-made ArCCs. The molecular dynamics (MD) software LAMMPS was used in conjunction with the ReaxFF/c force field to model the bond between cellulose and arabinan. A cellulose nanocrystal with dimensions 51 x 32 x 8 Å was minimized with various weight percent of water, 0%, 3%, 5%, 8%, 10%, and 12%. After the system was equilibrated for at least 100,000 femtoseconds, an arabinan molecule composed of 8 arabinose rings was added …

Self-Contained Breathing Apparatus For Firefighter With A Permanent Stoma, Jason Delgadillo, Aaron Wheeler, Zachary Wishbow

Biomedical Engineering

The purpose of this project was to create a unique SCBA (self-contained breathing apparatus) for a firefighter named Chris Gauer. This prototype consists of a SCBA headgear connected to a polycarbonate-formed stoma mask with a medical-grade sanitary silicone hose.

Electrospinning Of Polycaprolactone Core-Shell Nanofibers With Anti-Cancer Drug, Sakib Iqbal, Mujibur Khan, Saheem Absar, Andrew Diamanduros, Samuel Chambers

GS4 Student Scholars Symposium

Encapsulation of a model anti-cancer drug, 5-Fluorouracul (5-FU) into biocompatible core-shell nanofibers of polycaprolactone (PCL) nanofibers was fabricated using a coaxial electrospinning process. Our work aims to solve these issues using a novel method of fabrication of fibers featuring confinement of drugs within a biodegradable core-shell structure, thereby permitting sustained release of drugs to specific sites of treatment, such as tissues affected with tumor cells. The coaxial electrospinning was performed using a sheath polymer solution consisting of a 14 wt% PCL solution and a 5 wt% solution of 5-FU as the core solution. Dimethylformamide (DMF) was used as the solvent …

Assessing Viscoelastic Properties Of Polydimethylsiloxane (Pdms) Using Loading And Unloading Of The Macroscopic Compression Test, Mustafa Fincan

USF Tampa Graduate Theses and Dissertations

Polydimethylsiloxane (PDMS) mechanical properties were measured using custom-built compression test device. PDMS elastic modulus can be varied with the elastomer base to the curing agent ratio, i.e. by changing the cross-linking density. PDMS samples with different crosslink density in terms of their elastic modulus were measured. In this project the PDMS samples with the base/curing agent ratio ranging from 5:1 to 20:1 were tested. The elastic modulus varied with the amount of the crosslinker, and ranged from 0.8 MPa to 4.44 MPa. The compression device was modified by adding digital displacement gauges to measure the lateral strain of the sample, …

Surface Modification Of Traditional And Bioresorbable Metallic Implant Materials For Improved Biocompatibility, Emily Kristine Walker

Open Access Dissertations

Due to their strength, elasticity, and durability, a variety of metal alloys are commonly used in medical implants. Traditionally, corrosion-resistant metals have been preferred. These permanent materials can cause negative systemic and local tissue effects in the long-term. Permanent stenting can lead to late-stent thrombosis and in-stent restenosis. Metallic pins and screws for fracture fixation can corrode and fail, cause loss of bone mass, and contribute to inflammation and pain at the implant site, requiring reintervention. Corrodible metallic implants have the potential to prevent many of these complications by providing transient support to the affected tissue, dissolving at a rate …

Unveiling The Mechanical Behavior Of The Rod-Like Microstructure In The Radular Teeth Of Cryptochiton Stelleri, Enrique Escobar De Obaldia

Open Access Dissertations

Natural ceramics provided with high volume fractions of mineralized materials that are surrounded by a weak organic interface combine the stiff mechanical behavior of building blocks, like hydroxyapatite or aragonite, and the compliance of the organic surroundings. Unique mechanical properties (e.g. light density and toughness) distinguish bio-composites from common engineering materials. A key example is the highly mineralized shell of the radular teeth of the Crypochiton stelleri. Nature has provided the radular teeth with a highly oriented rod-like microstructure of nano-scale dimensions embedded in a matrix of chitin sheaths. Compared to other biological materials, the external iron oxide layer of …

Continual Cell Deformation Induced Via Attachment To Oriented Fibers Enhances Fibroblast Cell Migration, Sisi Qin, Vincent Ricotta, Marcia Simon, Richard A. F. Clark, Miriam Rafailovich

Department of Biomedical Engineering Faculty Publications

Fibroblast migration is critical to the wound healing process. In vivo, migration occurs on fibrillar substrates, and previous observations have shown that a significant time lag exists before the onset of granulation tissue. We therefore conducted a series of experiments to understand the impact of both fibrillar morphology and migration time. Substrate topography was first shown to have a profound influence. Fibroblasts preferentially attach to fibrillar surfaces, and orient their cytoplasm for maximal contact with the fiber edge. In the case of en-mass cell migration out of an agarose droplet, fibroblasts on flat surfaces emerged with an enhanced velocity, v …

Development Of Scaffold Architectures And Heterotypic Cell Systems For Hepatocyte Transplantation, Dalia Alzebdeh

Wayne State University Dissertations

In vitro assembly of functional liver tissue is needed to enable the transplantation of tissue-engineered livers. In addition, there is an increasing demand for in vitro models that replicate complex events occurring in the liver. However, tissue engineering of sizable implantable liver systems is currently limited by the difficulty of assembling three dimensional hepatocyte cultures of a useful size, while maintaining full cell viability, an issue which is closely related to the high metabolic rate of hepatocytes. In this study, we first compared two designs of highly porous chitosan-heparin scaffolds seeded with hepatocytes in dynamic perfusion bioreactor systems. The aim …

Biomimetic Oral Mucin From Polymer Micelle Networks, Sundar Prasanth Authimoolam

Theses and Dissertations--Chemical and Materials Engineering

Mucin networks are formed by the complexation of bottlebrush-like mucin glycoprotein with other small molecule glycoproteins. These glycoproteins create nanoscale strands that then arrange into a nanoporous mesh. These networks play an important role in ensuring surface hydration, lubricity and barrier protection. In order to understand the functional behavior in mucin networks, it is important to decouple their chemical and physical effects responsible for generating the fundamental property-function relationship. To achieve this goal, we propose to develop a synthetic biomimetic mucin using a layer-by-layer (LBL) deposition approach. In this work, a hierarchical 3-dimensional structures resembling natural mucin networks was generated …

Understanding The Role Of Colloidal Particles In Electroporation Mediated Delivery, Alisha Peterson

USF Tampa Graduate Theses and Dissertations

Electroporation (EP) is a physical non-viral technique used to deliver therapeutic molecules across the cell membrane. During electroporation an external electric field is applied across a cell membrane and it causes pores to form. These pores then allow the surrounding media containing the therapeutics to diffuse across the membrane. This technique has been specifically studied as a promising gene and drug delivery system. Colloidal particles have also proven to be promising for a variety of biological applications including molecular delivery, imaging, and tumor ablation, due to their large surface area and tunable properties. In more recent years researchers have explored …

Healing Of Bone Defects In A Rodent Calvarial Defect Model Using Strong Porous Bioactive Glass (13-93) Scaffolds, Yinan Lin

Masters Theses

"The main objective of this project was to evaluate the capacity of strong porous silicate (13-93) bioactive glass scaffolds prepared by a robocasting technique to regenerate bone and stimulate angiogenesis in a rat calvarial defect model. The scaffolds were created with the same grid-like microstructure but in a variety of formulations: (i) as-fabricated, (ii) pretreated in an aqueous phosphate solution to convert the glass surface to hydroxyapatite, (iii) loaded with bone morphogenetic protein-2 (BMP2) (1 µg per scaffold), and (iv) doped with copper (0.4-2.0 wt. % CuO). When compared to the as-fabricated scaffolds, the pretreated scaffolds enhanced bone regeneration at …

Multi-Platform Arabinoxylan Scaffolds As Potential Wound Dressing Materials, Donald C. Aduba Jr

Theses and Dissertations

Biopolymers are becoming more attractive as advanced wound dressings because of their naturally derived origin, abundance, low cost and high compatibility with the wound environment. Arabinoxylan (AX) is a class of polysaccharide polymers derived from cereal grains that are primarily used in food products and cosmetic additives. Its application as a wound dressing material has yet to be realized. In this two-pronged project, arabinoxylan ferulate (AXF) was fabricated into electrospun fibers and gel foams to be evaluated as platforms for wound dressing materials. In the first study, AXF was electrospun with varying amounts of gelatin. In the second study, AXF …