Biomedical Engineering and Bioengineering Commons^™

Degradability Of Poly(Ethylene) Based Microgels And Methods Of Improving High Polydispersity Index, Abrar Alniemi

Williams Honors College, Honors Research Projects

In order to improve upon the utilization of poly(ethylene glycol) (PEG) microgel-based scaffolds in drug delivery applications, this work explores the use of degradable and non-degradable PEG for tunable scaffolds. Previously, issues concerning the required uniformity in microgel size and low polydispersity index have been encountered. As such, methods of refining polymer synthesis, microgel fabrication, and microgel size separation were explored. Overall, no solution has been found to correct the issue for the microgels were still observed to have high polydispersity index regardless of varied troubleshooting alterations.

Development Of Entubulation Strategies For Treating Central Nervous System Injuries, Ivy Brosch

Williams Honors College, Honors Research Projects

According to the McKnight Brain Institute, at least 10,000 people annually in the USA suffer from a central nervous system (CNS) injury. These injuries can cause serve disabilities including paralysis. Due to the complexity of the spinal cord, it is common that potential CNS treatments are first applied to an optic nerve crush (ONC) model in rats. Two proposed treatments were employed; one where nerve growth factor (NGF) was immobilized to a chitosan substrate to stimulate axonal regeneration, and the other using pentadecafluorooctanoyl chloride modified methacrylamide chitosan (MAC(Ali15)F) hydrogel to enhance local oxygenation. The two different treatments were formed into …

Engineering Surface Properties To Modulate Inflammation And Stem Cell Recruitment Through Macrophage Activation, Kelly M. Hotchkiss

Theses and Dissertations

Biomaterials are becoming the most commonly used therapeutic method for treatment of lost or damaged tissue in the body. Metallic materials are chosen for high strength orthopaedic and dental applications. Titanium (Ti) implants are highly successful in young, healthy patients with the ability to fully integrate to surrounding tissue. However the main population requiring these corrective treatments will not be healthy or young, therefore further research into material modifications have been started to improve outcomes in compromised patients. The body’s immune system will generate a response to any implanted material, and control the final outcome. Among the first and most …

Electrochemical And Spectroscopic Study Of Peptide-Template Melanins, Daniel Courter, Olivia Rossi, Zhen Tian

Honors Theses and Capstones

Melanins are organic polymers made up of 5,6-dihydroxyindole carboxylic acid (DHICA) and 5,6-dihydroxyindole (DHI). Biochemical systems synthesize melanins through a complex reaction pathway. Previous research exhibited that naturally-occurring melanins (NatMel) and their synthetic analogues (SynMel) can potentially serve as electrode materials for aqueous charge storage devices. Small surface area creates technical challenges for these melanins as charge storage materials. This research herein demonstrates that the structure of melanins can affect the charge storage capacities of monovalent Na⁺cations and divalent Mg²⁺ cations. 2-D sheet-like peptide melanins (PepMel) were synthesized into tripeptides consisting of aspartic acid (D), phenylalanine (F), …

Integration Of Biology, Ecology And Engineering For Sustainable Algal‑Based Biofuel And Bioproduct Biorefinery, James Allen, Serpil Unlu, Yaşar Demirel, Paul N. Black, Wayne R. Riekhof

Department of Chemical and Biomolecular Engineering: Faculty Publications

Despite years of concerted research efforts, an industrial-scale technology has yet to emerge for production and conversion of algal biomass into biofuels and bioproducts. The objective of this review is to explore the ways of possible integration of biology, ecology and engineering for sustainable large algal cultivation and biofuel production systems. Beside the costs of nutrients, such as nitrogen and phosphorous, and fresh water, upstream technologies which are not ready for commercialization both impede economic feasibility and conflict with the ecological benefits in the sector. Focusing mainly on the engineering side of chemical conversion of algae to biodiesel has also …

An Injectable Thermosensitive Biodegradable Hydrogel Embedded With Snap Containing Plla Microparticles For Sustained Nitric Oxide (No) Delivery For Wound Healing, Nikhil Mittal

Dissertations, Master's Theses and Master's Reports

After injury, wound healing is a complex sequential cascade of events essential for the proper recovery of the wound without the scar formation. Nitric oxide (NO) is a small, endogenous free-radical gas with antimicrobial, vasodilating and growth factor stimulating properties. NO has wide biomedical application especially in wound healing however, its usability is hindered due its administration problem as it is highly unstable.

In this work, poly (l-lactic acid) microparticles encapsulated with NO donor S-nitroso-N-acetyl-D-penicillamine (SNAP) were prepared using water-in-oil-water double emulsion solvent evaporation method for controlled delivery for NO at the specific site. The NO release from SNAP-PLLA microparticles …

Reversibly Switching Adhesion Of Smart Adhesives Inspired By Mussel Adhesive Chemistry, Ameya R. Narkar

Dissertations, Master's Theses and Master's Reports

Catecholic groups in mussel adhesive proteins transition from being strongly adhesive in a reduced state under acidic conditions to being weakly adhesive in an oxidized state under basic conditions. Here, we exploit this pH responsive behavior of catechol and demonstrate that its oxidation state can be manipulated by incorporation of boronic acid to facilitate reversible transitions between strong and weak adhesion. Our first approach involved the addition of 3- acrylamido phenylboronic acid (APBA) to dopamine methacrylamide (DMA) containing adhesives. The synthesized adhesives showed strong adhesion to quartz surface in an acidic medium (pH 3), while weak adhesion was observed on …

Studying Mass And Mechanical Property Changes During The Degradation Of A Bioadhesive With Mass Tracking, Rheology And Magnetoelastic (Me) Sensors, Zhongtian Zhang

Dissertations, Master's Theses and Master's Reports

In this research, the degradable polymer 4-arm poly (ethylene glycol)-glutaric acid-dopamine (PEG-GA-DM₄) was synthesized. The degradation behavior of crosslinked PEG-GA-DM₄ bioadhesive was studied with mass tracking, oscillatory rheology, and magnetoelastic (ME) sensors. Changes in mechanical properties were correlated with both dry mass and wet mass changes during the degradation. The results indicate that the loss of mechanical property in the bioadhesive can take place without losing the dry mass. The mass loss profile cannot describe the degradation behavior completely. In addition to studying the degradation of PEG-GA-DM₄, this research also confirms the application of ME …

Collapsible Silicone Tubes: An In Vitro Model For Tracheal Traction, Kevin D. Garman

Master's Theses (2009 -)

Obstructive sleep apnea (OSA) is characterized by recurrent episodes of airway collapse and airflow limitation during sleep. Fragmented sleep and reductions in blood oxygen saturation lead to several comorbidities, including hypertension, cardiovascular disease, and cerebrovascular disease. Longitudinal forces (tracheal traction) acting on the soft tissues surrounding the upper airway have been proposed to play a significant role in stabilizing the airway and preventing collapse. However, the relative contribution of longitudinal forces as compared to other factors that affect airway stability (airway geometry, tissue properties, muscle activity) remains unclear. This in-vitro study aimed to investigate to what extent longitudinal forces can …

Development Of Starch-Polyvinyl Alcohol (Pva) Biodegradable Film: Effect Of Cross-Linking Agent And Antimicrobials On Film Characteristics, Aniket Satish More, Chandani Sen, Madhusweta Das

Journal of Applied Packaging Research

To satisfy the need of developing eco-friendly flexible antimicrobial packaging film with minimum use of synthetic chemical ingredients, the present study examined the efficacy of citric acid (CA) as cross-linking agent and essential oils (EOs), viz., cinnamon essential oil (CEO) and oregano essential oil (OEO) as natural antimicrobials in corn starch-polyvinyl alcohol (CS-PVA) film. Compared to film prepared from filmogenic solution (FS) containing 75 kg CS+8.75 kg PVA+24.6 kg glycerol per m³ FS, film additionally containing CA at 0.07 kg/kg CS indicated 95% higher ultimate tensile strength (UTS) and 27% lower water vapor permeability (WVP). Film developed with incorporation …

Identifying And Reducing Variability, Improving Scaffold Morphology, And Investigating Alternative Materials For The Blood Vessel Mimic Lab Electrospinning Process, Evan M. Dowey

Master's Theses

The work of the Cal Poly Tissue Engineering Lab is primarily focused on the fabrication, characterization, and improvement of “Blood Vessel Mimics” (BVMs), tissue engineered constructs used to evaluate cellular response to vascular medical devices. Currently, cells are grown onto fibrous, porous tubes made using an in-house electrospinning process from PLGA, a biocompatible co-polymer. The adhesion and proliferation of cells in a BVM is reliant on the micro-scale structure of the PLGA scaffold, and as such it is of great importance for the electrospinning process to consistently produce scaffolds of similar morphologies. Additionally, it has been shown that cell proliferation …

Rice Hull Bioreactor For Recirculating Aquaculture, Marlon A. Greensword

LSU Doctoral Dissertations

The engineering of floating media biofilters has been optimized over the years. The backwashing process has made them more energy and water efficient. Likewise, moving bed bioreactors (MBBR) are gaining interest and popularity because they are relatively affordable to build. Yet, developing countries’ aquaculture production remains largely excluded from the advances made in recirculating aquaculture systems (RAS). This discrepancy is partially driven by the high costs of media such plastic beads and Kaldnes (KMT) media, commonly used in MBBR.

This dissertation evaluates the usability and profitability of rice hulls (RH), an abundant by-product in many developing nations, as a sinking …

How Strongly Do Oysters Stick?, Nicolás M. Morato, Andrés M. Tibabuzo, Jonathan J. Wilker

The Summer Undergraduate Research Fellowship (SURF) Symposium

Biological adhesives are a type of interfacial material that has incredible potential to generate new biomimetic compounds that can replace current strong, but toxic, adhesives. Therefore, a study of the chemical composition and mechanical properties of those bio-adhesives is necessary. However, in the case of oysters, despite known chemical characterization of the adult’s adhesive, there are almost no studies on its mechanical properties. Furthermore, there is no available information on the adhesive properties of spat (oysters in their larvae state). Herein, we present the first mechanical characterization of the spat adhesive, measuring its adhesion strength by hydrodynamic determination using a …

Study Of Iron Ion Transit Through Three-Fold Channel Of Ferritin Cage, Shah Alam Limon

Graduate Theses/Dissertations

Ferritin is an iron-storage globular protein with an ability to uptake, mineralize and release iron ions in a controllable manner. The globular hollow shell allows storage of mineralized iron, with several channels responsible for the transit of ions into the shell and out of it. Understanding of the detailed molecular functioning of ferritin is required for rational design of biomimetic conjugate nano-biosystems containing ferritin-like constituents. In this work, ferritin was investigated both numerically by all-atom molecular dynamics (MD) simulations, and experimentally by Raman spectroscopy. Molecular dynamic simulations of a model system comprising iron ions (Fe2+) and a ferritin trimer expressing …

A Wood-Powered Lawn Mower: Separating The Rules Of Thumb From Engineering Design, William White

Mahurin Honors College Capstone Experience/Thesis Projects

Biomass gasification, the thermal process of exracting combustible gasses from organic matter, is an established procedure that has been used for many years to provide fuel in various applications. It is a potential source of renewable fuel and has proven useful as a crisis energy source. This thesis investigates the primary engineering science principles involved in gasifier-engine system design. It arises from and supplements a WKU mechanical engineering senior project. The senior project has developed a wood gasification system designed to power a riding lawn mower. The thesis reiews theory-based design and separates it from informal hit and miss approaches—rule …

A Tunable, Three-Dimensional In Vitro Culture Model Of Growth Plate Cartilage Using Alginate Hydrogel Scaffolds, Alek G. Erickson, Taylor D. Laughlin, Sarah Romereim, Catherine Sargus-Patino, Angela K. Pannier, Andrew T. Dudley

Department of Agricultural and Biological Systems Engineering: Faculty Publications

Defining the final size and geometry of engineered tissues through precise control of the scalar and vector components of tissue growth is a necessary benchmark for regenerative medicine, but it has proved to be a significant challenge for tissue engineers. The growth plate cartilage that promotes elongation of the long bones is a good model system for studying morphogenetic mechanisms because cartilage is composed of a single cell type, the chondrocyte; chondrocytes are readily maintained in culture; and growth trajectory is predominately in a single vector. In this cartilage, growth is generated via a differentiation program that is spatially and …

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 …

Patient-Derived Hydrogel As A Sacrificial Matrix For Efficient Cell Loading, Shalmli U. Joshi

Honors Scholar Theses

The field of tissue engineering focuses on delivering patient-derived stem cells to the body through the use of degradable biomaterials, such as hydrogels, which are infused into engineered scaffolds. Hydrogels act as templates to support and guide cells towards the regeneration of new tissue. In this study, we introduce a completely intraoperative procedure for obtaining a fibrin hydrogel for tissue engineering applications. In the past, fibrin hydrogel has been commonly formed by combining fibrinogen protein with animal-derived thrombin. Instead, we have developed an automated, and therefore reproducible, protocol to isolate and form fibrin hydrogel without the use of animal-derived thrombin. …

Chitosan Nanoparticle Modifications For Improved Gene Delivery In An Oral Dna Vaccine Application, Austin Helmink

Honors Program: Senior Projects (Public)

Vaccines represent one of the most significant medical innovations of the 20^th century, resulting in the eradication or near eradication of a handful of deadly diseases. However, many infectious diseases remain resistant to effective vaccination, largely due to a lack full immune activation by traditional protein-based vaccines. A promising alternative vaccination strategy is the emerging development of DNA vaccines, which rely upon the delivery of exogenous genetic material to host cells encoding for a viral or bacterial antigen in order to induce a robust immune response by closely mimicking live infection. The delivery of genetic material requires a carrier …

Toxicity Evaluation Of Magnetic Hyperthermia Induced By Remote Actuation Of Magnetic Nanoparticles In 3d Micrometastasic Tumor Tissue Analogs For Triple Negative Breast Cancer, Nathanael A. Stocke, Pallavi Sethi, Amar Jyoti, Ryan Chan, Susanne M. Arnold, J. Zach Hilt, Meenakshi Upreti

Chemical and Materials Engineering Faculty Publications

Magnetic hyperthermia as a treatment modality is acquiring increased recognition for loco-regional therapy of primary and metastatic lung malignancies by pulmonary delivery of magnetic nanoparticles (MNP). The unique characteristic of magnetic nanoparticles to induce localized hyperthermia in the presence of an alternating magnetic field (AMF) allows for preferential killing of cells at the tumor site. In this study we demonstrate the effect of hyperthermia induced by low and high dose of MNP under the influence of an AMF using 3D tumor tissue analogs (TTA) representing the micrometastatic, perfusion independent stage of triple negative breast cancer (TNBC) that infiltrates the lungs. …

The Sub-Chronic Vascular Response To Water-Borne Embolic Coacervates., Joshua P. Jones, Monika Sima, Russell J. Stewart

Biomedical Engineering Western Regional Conference

Water-borne coacervates that solidify in response to decreasing ionic strength have been developed as an agent for small vessel transcatheter embolization. Here, the sub-chronic vascular response to these agents will be presented. Embolic coacervates demonstrated a benign foreign body response, which supported tissue ingrowth and stabilized vessel occlusion out to 28 days. As with other liquid embolics, occlusion is dependent upon mechanical obstruction of the vessel and native thrombus. Over time, the thrombus becomes more organized by fibroblasts. Continuation of the processes seen at 28 days will likely result in fibrous encapsulation of the embolic coacervate, further stabilizing the occlusion.

Differentiation And Containment Of Derived Pancreatic Beta Cells, Caden Duffy, Alonzo Cook Ph.D.

Biomedical Engineering Western Regional Conference

Currently, the only permanent cure for Type 1 Diabetes is a pancreatic or islet transplant. With the shortage of donors, we are progressing research towards alternative therapies by differentiating induced pluripotent stem cells into derived pancreatic β-cells that can be transplanted and used as treatment for Type 1 Diabetes. We are investigating methods to increase the yield of fully derived, insulin producing pancreatic β-cells and are additionally researching the use of hydrophilized expanded polytetrafluoroethylene for use in cell containment devices. These devices could offer a future alternative for islet transplantation in human patients.

Super-Hydrophobic And Anti-Microbial Surfaces Via Carbon Infiltrated-Carbon Nanotubes, Christian Dalon Esplin, Anton Bowden, Brian Jensen

Biomedical Engineering Western Regional Conference

No abstract provided.

Structural Mrsa Resistance Through Carbon-Infiltrated Carbon Nanotube Coating Of External Fixator Pins, Jaclyn Larsen, Stephanie Morco, Brian Jensen, Anton Bowden

Biomedical Engineering Western Regional Conference

No abstract provided.

Resorption Rate Of Bioresorbable Materials For Possible Use In Self-Expanding Stents, Jared R. Park, Jason Porter, Anton Bowden

Biomedical Engineering Western Regional Conference

This study investigates the mechanical behavior of various polymers after a period of degradation from exposure to a Saline Solution. The study found that PLA and PDLLA do not have significant degradation over a period of 2 months, while PLA has a sharp decrease in strength after 7 days.

Effect Of Multiple Confined Compression/Stress Relaxation Cycles On Cross-Linked Alginate Pore Size., Sindhu Kolar Venkat, Erik L. Risa, Bergren Antell, Maryam Mobed-Miremadi

Biomedical Engineering Western Regional Conference

No abstract provided.

Towards A Bioselective Surface For Treatment Of Sepsis In A Hemoperfusion Device, Karl F. Schilke, Ramya Raman, Bonan Yu, Erik Hahn, Jonathan Su

Biomedical Engineering Western Regional Conference

Sepsis is a dysregulated immune response to circulating bacteria/endotoxin. Hemoperfusion is a promising treatment, but is not universally effective and can unacceptable blood damage. We are developing protein-repellent hydrogel nanofilms that can be grown on a variety of surfaces, and functionalized with “click-ready” pathogen-binding proteins expressed by Genetic Code Expansion (GCE). The extremely rapid, bioorthogonal “click” immobilization chemistry eliminates prior purification, maximizes surface loading, and guarantees spatial orientation of the immobilized proteins. We have demonstrated pathogen binding and blood protein repulsion by these layers, suggesting that they may be part of effective treatments for sepsis and other applications.

Molecular Modeling Of Antibody-Antigen Binding Near Solid Surfaces, Derek Bush, Thomas Knotts

Biomedical Engineering Western Regional Conference

Antibody microarrays are biosensors that have the potential to revolutionize molecular detection in medicine, scientific research, and national defense. However, current microarrays are not widely used due to problems including poor reproducibility and signal quality, unbalanced antibody performance, and cross-reactivity. Prior work in the area focused mainly on the stability of the antibody alone and not its affinity for its antigen. This presentation shows results of using molecular simulation to determine how different types of surfaces affect antigen binding to surface-tethered antibodies. The results offer an unprecedented, molecular-level view into these protein-protein-surface interactions and how to drive binding to occur.

The Effect Of Tgfβ-1 On Adipose-Derived Stem Cell (Asc) Ring Constructs, Ashley C. Apil

Research Opportunities for Engineering Undergraduates (ROEU) Program 2016-17

Adipose-derived Stem Cells (ASC’s) provide an optimal source for potentially graft replacing, tissue-engineered vessel constructs due to their ease of extraction and ability to be patient-specific. In order to make ASC ring constructs a more viable replacement for grafts, they need to have mechanical properties similar to native arteries, which is largely influenced by the extracellular matrix protein collagen. TGFβ-1 is known to stimulate collagen production in ASC’s, so this study explores the effect that TGFβ-1 has on the resulting thickness and tensile strength of ASC ring constructs.

Synthesis And Characterization Of Poly(Simvastatin) - Incorporated Copolymers And Blends For Bone Regeneration, Theodora Asafo-Adjei

Theses and Dissertations--Biomedical Engineering

Common biodegradable polyesters such as poly(lactic acid) (PLA), poly(lactic-co-glycolic acid) (PLGA) and poly(ε-caprolactone) (PCL) are used as drug delivery vehicles for tissue regenerative applications. However, they are typically bioinert, with drug loading limitations. Polymerizing the active agent or precursor into its respective biodegradable polymer would control drug loading via molar ratios of drug to initiator used for synthesis. Simvastatin was chosen due to its favorable anti-inflammatory, angiogenic, and osteogenic properties. In addition, its lactone ring lends itself to ring-opening polymerization and, consequently, the synthesis of poly(simvastatin) with controlled simvastatin release.

Simvastatin was first polymerized with a 5kDa methyl-terminated poly(ethylene glycol) …