Biomaterials Commons^™

Fluorescence Characterization Of Quantum Dots For Use As Biomarkers, Logan M. Grimes

Materials Engineering

Fluorescence profiles of quantum dots (QDs) were characterized to select the ideal QDs for encapsulation in phospholipids for use as biomarkers to selectively adhere to cancer cells. QDs were synthesized and extracted 0, 30, 60, and 90 seconds after precursor compounds were mixed. These extractions were isolated by extraction time. Portions from each vial were coated in a zinc sulfide shelling procedure, leaving at least half of the QD solution unshelled. These samples were characterized over four days to monitor fluctuations in fluorescence. This was done utilizing an Ocean Optics spectrometer in conjunction with Spectra Suite software. The central wavelength, …

Evaluation Of Thermophile Algae In Horizontal Photo-Bioreactor, Olivier Schmied

BioResource and Agricultural Engineering

No abstract provided.

Shelf Life Study Of Electrospun Plga Copolymers, Sean Youra, Nick Hudson

Biomedical Engineering

Poly(lactic-co-glycolic acid) (PLGA) is one of the most commonly used copolymers for electrospinning in tissue engineering applications. However, most research has not focused on the copolymer itself in regards to how long it can be used effectively and if varying the concentrations of polylactic acid (PLA) and polyglycolic acid (PGA) affect the resulting properties. Electrospinning is the method we use to create the three-dimensional constructs, or “scaffolds”, for the blood vessel mimic (BVM) in the tissue engineering lab. The aim of our project was to investigate if the morphology and mechanical properties of the scaffolds changed over time when they …

Modeling The Zimmer Fitmore And Ml Taper Implantation, Tyler Kazuo Franklin

Master's Theses

With more young adults requiring total hip

arthroplasties the need for bone saving implants becomes

more important. The Zimmer Fitmore is a new bone saving

implant that utilizes an implantation technique that

reduces the damage to the muscle tissue allowing for

patients to have a short recovery time as well as a new

design that allows it to rest on the medial cortex. There

has been anecdotal evidence that this device leads to early

revision within six months of implantation due to failures

occurring in the medial cortex. The main goal of this

study was to computationally model the Zimmer …

Design Of An Experimental Approach To Study The Growth Of Biofilm On Polymethylmethacrylate, Eireen S. Escalona

Biomedical Engineering

Biofilms are present in virtually every solid-liquid contact surface and are partially responsible for some diseases and water cleaning. They are a community of a variety of organisms that live symbiotically and are bound together by extracellular polymeric substances, or EPS. Biofilms go through five stages of development. These include initial and irreversible attachments, maturations I and II, and dispersion. In the dental world, biofilms are often associated with mouth infections including dental caries, gingivitis and periodontitis. Elderly denture wearers are susceptible to the pathogen-causing bacteria associated with these diseases, particularly those who have Alzheimer's disease or other forms of …

Bacterial Growth On Metal And Non-Metal Surfaces In A Static Bioreactor, Rolan Yuk Loong Liong

Master's Theses

Research was conducted to observe bacterial growth on the surface of metals in a static bioreactor. Metal and non-metal samples were subjected to bacterial exposure (1 day and 9 days). The metal samples were surface treated prior to bacterial exposure. The microstructures of the surface treated samples were analyzed by optical microscopy. After exposure, the microstructures of the samples were analyzed by scanning electron microscopy (SEM). The analysis suggested that microbial attachment on the surface was related to the underlying microstructure of steel. The preferential attachment of microbes could potentially be influenced by cathodic and anodic regions created by the …

Development Of In Vitro Tissue Engineered Blood Vessel Mimics In Complex Geometries For Coronary Stent Testing, Robert Dalton Chavez

Master's Theses

Coronary heart disease is the leading cause of death in the United States and occurs when plaque occludes coronary arteries. Coronary stents, which may be used to treat coronary occlusions, are small metal tubes that are implanted in coronary arteries to restore blood flow. After stent implantation, endothelial cells grow over the stent so that blood contacts the endothelial cells instead of the stent surface; this event is known as re-endothelialization. Re-endothelialization prevents blood from clotting on the stent surface and is a good predictor of stent success. Blood vessel mimics (BVMs) are in vitro tissue engineered models of human …

Design Of Experimentation To Systematically Determine The Interaction Between Electrospinning Variables And To Optimize The Fiber Diameter Of Electrospun Poly (D, L-Lactide-Co-Glycolide) Scaffolds For Tissue Engineered Constructs, Yvette S. Castillo

Master's Theses

Cardiac disease causes approximately a third of the deaths in the United States. Furthermore, most of these deaths are due to a condition termed atherosclerosis, which is a buildup of plaque in the coronary arteries, leading to occlusion of normal blood flow to the cardiac muscle. Among the methods to treat the condition, stents are devices that are used to restore normal blood flow in the atherosclerotic arteries. Before advancement can be made to these devices and changes can be tested in live models, a reliable testing method that mimics the environment of the native blood vessel is needed. Dr. …

Corrosion Of Stainless Steel 316l And Astm F75 Cobalt Chromium Alloy During Immersion Testing In Silver Salt Solutions, Meagan Higgins

Materials Engineering

This study evaluates the potential effects of silver salts on biocompatible metals used for prostheses during the chemical reduction process to produce a silver antimicrobial layer on the metal’s surface. Samples of two biocompatible metals were obtained: Stainless Steel 316L and ASTM F75 Cobalt Chromium Alloy. Three different silver salts were also acquired: silver nitrate, silver sulfadiazine, and silver chloride. Specimens of each metal were cut to size using a 4-1/2 inch aluminum oxide, 40 grit, cut off wheel for metal, attached to a Dewalt Angle Grinder. The biocompatible metal samples were then subject to either Solution 1, water with …

The Characterization Of Biofilm Attachment To Metal Interfaces: Effects Of Substratum Properties, Marcel D. Mendes

Master's Theses

Bacteria are among the most abundant microorganisms on earth, and can be found in essentially every environment. When a clean surface is exposed to media containing planktonic bacteria, the bacterial cells will attach to the surface and aggregate to form what is known as a biofilm. Biofilms have been shown to negatively affect many industries including medical, industrial, and food science applications. While biofilms have been well characterized from a microbiology perspective, there has been much less research from a materials science standpoint. It is hypothesized that the material properties of the substratum (such as the micro-structure) have a significant …

Evaluation Of Decellularization Procedures For Porcine Arteries, Charles Clapp

Biomedical Engineering

Coronary artery disease has become the leading cause of death in the United States, with over 425,000 deaths in 2006. Stenting has evolved into the preferred preventative technique for myocardial infarction by opening up an occluded artery, due to its low invasiveness compared to the alternative of coronary artery bypass grafting. Bare metal stents have been improved by coating with anti-proliferative drugs to advance their effects, but even drug eluting stents still have a risk of restenosis, thrombus formation, and necessary revascularization. Continual advancement in stent design necessitates faster, effective pre-clinical evaluation techniques. Kristen Cardinal, Ph.D., developed the blood vessel …

Improved Manufacturing Methods Of Bovine Femur Samples For Ultrasonic Testing And Assessment Of Materials Through Contract Angle Measurement, Kevin Mathew Lopez Galang

Biomedical Engineering

At California Polytechnic State University of San Luis Obispo (Cal Poly), the Biomedical Engineering department (BMED) requires its students to take the course listed as “BMED 420: Principles of Biomaterial Designs.” BMED 420 has a required laboratory section every week throughout the duration of the course that is meant to be a supplemental tool for learning. During the lab sections, students perform experiments and exercises that are currently being implemented in the industry. Despite accuracy of the methods and experiments relative to their use in the industry, there is always room for improvement. The objective of this project will illustrate …

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. …

Development Of An In-Vitro Hyperglycemic Tissue Engineered Blood Vessel Mimic, Brian C. Wong

Biomedical Engineering

No abstract provided.

Mammary Epithelial Cell Growth On A Three-Dimensional Scaffold In An Operating Bioreactor, Melissa Marie Davalle

Master's Theses

Mammary epithelial cells are highly efficient secreting cells. With genetic engineering, the uses of these cells could be endless. Research is being conducted on these cells to determine their full potential to the biotech industry.

This paper investigates whether bovine epithelial mammary cells can survive in glutaraldehyde-treated gelatin tubes in an operating bioreactor. Many bioreactors were developed and tested to suit the needs of the cells. Procedures were created and carried out to ensure sterility of the bioreactors. Bovine mammary epithelial cells were implanted in the bioreactors and samples of their growth were taken over time.

Design And Development Of Two Test Fixtures To Test The Longitudinal And Transverse Tensile Properties Of Small Diameter Tubular Polymers, Carolyn Berry

Master's Theses

Hundreds of thousands of vascular bypass grafts are implanted in the United States every year, but there has yet to be an ideal graft material to substitute for one’s own autologous vessel. Many synthetic materials have been shown to be successful vessel replacements; however, none have been proven to exhibit the same mechanical properties as native vessels, one of the most important criteria in selecting a vascular graft material. Part of this issue is due to the fact that, currently, there is no “gold standard” for testing the longitudinal and transverse tensile properties of small diameter tubular materials. While there …

An Investigation Of Process Parameters To Optimize The Fiber Diameter Of Electrospun Vascular Scaffolds Through Experimental Design, Steffi Wong

Biomedical Engineering

No abstract provided.

A Rapid Prototyping Method For Constructing A Complex Three-Dimensional Substrate, Kathryn Jacoba Hart

Master's Theses

Cell culturing on three-dimensional structures has increased the possibilities in tissue engineering and bioreactor research. These structures enable cells to differentiate, proliferate, mobilize, and function in a conformation that more accurately mimics in vivo conditions. Computer generated models aid in development and rapid alteration of three-dimensional cell substrates, defining their internal structure as well as their external morphology. The rapid transition from substrate design to a viable culture is imperative to quickly advance research in biomedical and tissue engineering applications.

The aim of this thesis is to investigate the feasibility of a rapid prototyping process by selectively cross-linking and assembling …

Assessment Of Electrospinning As An In-House Fabrication Technique For Blood Vessel Mimic Cellular Scaffolding, Colby M. James

Master's Theses

Intravascular devices, such as stents, must be rigorously tested before they can be approved by the FDA. This includes bench top in vitro testing to determine biocompatibility, and animal model testing to ensure safety and efficacy. As an intermediate step, a blood vessel mimic (BVM) testing method has been developed that mimics the three dimensional structure of blood vessels using a perfusion bioreactor system, human derived endothelial cells, and a biocompatible polymer scaffold used to support growth of the blood vessel cells. The focus of this thesis was to find an in-house fabrication method capable of making cellular scaffolding for …

The Effect Of Particle Surface Area To Volume Ratio On Ion Release From Cocr Spheres, Darin J. Grandfield

Master's Theses

In 2005, over 200,000 Americans underwent a hip arthroplasty, the replacement of a hip joint with an artificial prosthesis. Of these arthroplasties, metal-on-metal type implants represent an increasing usage percentage. Metal-on-metal implants are selected largely for their low volumetric wear rate, durability, and resistance to corrosion. In spite of these advantages, little is known concerning the long-term consequences of heavy metal alloy use in the body, although early research indicates potentially carcinogenic results. This thesis is a preliminary investigation into these long term effects and their root causes.

An improved comprehension of the corrosion kinetics and the rate of ion …

Evaluating The Electrical Response Of Polyaniline To Mechanical Strain, Matthew L. Goebel

Master's Theses

This thesis focuses on the electrical output of polyaniline films subjected to uniaxial strain in hydrochloric acid solutions. Polyaniline belongs to novel class of materials known as conducting polymers. Alternating single and double bonds in the backbone of conducting polymers allow them to transmit electric charge when they are doped with negatively charged ions. Modifying the degree of doping and other electrical/chemical treatments allow conducting polymers to exhibit conducting, semi-conducting, or insulating electrical properties. Resilient mechanical properties, good processability, and low cost make conducting polymers good candidates for applications traditionally held by metals and semi-conductors.

When tensile strain is applied …

Preparation And Characterization Of Electrospun Poly(D, L-Lactide-Co-Glycolide) Scaffolds For Vascular Tissue Engineering And The Advancement Of An In Vitro Blood Vessel Mimic, Tiffany Richelle Pena

Master's Theses

PREPARATION AND CHARACTERIZATION OF ELECTROSPUN POLY(D,L-LACTIDE-CO-GLYCOLIDE) SCAFFFOLDS FOR VASCULAR TISSUE ENGINEERING AND THE ADVANCEMENT OF AN IN VITRO BLOOD VESSEL MIMIC

Tiffany Richelle Peña

Currently, an estimated 1 in every 3 adult Americans are affected by one or more cardiovascular complications. The most common complication is coronary artery disease, specifically atherosclerosis. Outcomes of balloon angioplasty treatments have been significantly improved with the addition of drug eluting stents to the process. Although both bare metal and drug eluting stents have greatly increased the effectiveness of angioplasty and decreased the occurrence of restenosis, several complications still exist. For this reason, the stent …