Engineering Commons^™

Automated Methods For Fiber Diameter Measurement Of Fibrous Scaffolds, Anna Bulysheva

Theses and Dissertations

The purpose of this work was to develop an automated method of measuring fiber diameters of electrospun scaffolds from scanning electron microscopy images of these scaffolds. Several automated methods were developed and evaluated by comparison to known values and data obtained via the standard manual method. Simulated images with known diameters were used as test images to evaluate the accuracy of each measurement technique. Eight scanning electron microscopy images were also used for the evaluation of the automated methods compared to the standard manual method. All diameter measurements were made in pixels. Five new automated methods coded in MATLAB were …

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 …

Preparation And Characterization Of An Electrospun Gelatin/Dendrimer Hybrid Nanofiber Dressing, Alicia P. Smith-Freshwater

Theses and Dissertations

A novel dendritic wound dressing was designed and characterized for its potential to treat chronic wounds. Comprised of gelatin, dendrimer, synthetic polymer and antibiotics, the dressing was electrospun to mimic the natural extracellular matrix (ECM). Gelatin is biocompatible, biodegradable, non-toxic, and easily available. The antibiotic, doxycycline, has the ability to inhibit matrix metalloproteinases. Matrix metalloproteinases, which occur in excess in chronic wounds, degrade the reconstituted ECM. Starburst™ polyamidoamine (PAMAM) dendrimer G3.5, which provides a versatile and structurally controlled architecture to construct nanomedicine, was covalently bonded to the gelatin backbone and electrospun into nanofibers with gelatin, doxycycline and stabilizing polymers. The …

The Production And Filtration Efficiency Testing Of Nonwoven Electrospun Fiber Mats, Jan Uecker

Theses and Dissertations

In this thesis the production and filtration performance of electrospun nylon-4,6 nanofiber mats was experimentally studied. The average fiber diameter of nylon-4,6 fibers is controlled by altering the polymer concentration in solution. Adding small amount of pyridine to the electrospinning solution controlled fiber beading and other defects. These fibers were then deposited onto a wide variety of conductive and dielectric substrate materials. A corona ion source was used to eliminate surface charging effects observed at the surface of all substrates. The resulting fiber mats, uniform in size and distribution as verified by SEM imaging, are tested for filtration efficiency and …

Fabrication And Characterization Of Bioactive, Composite Electrospun Bone Tissue Engineering Scaffolds Intended For Cleft Palate Repair, Parthasarathy Madurantakam

Theses and Dissertations

Tissue Engineering is a scientific discipline that aims to regenerate tissues and organs that are diseased, lost or congenitally absent. It encompasses the use of suitable synthetic equivalents of native extracellular matrix that may or may not be supplemented with cells or relevant growth factors. Such scaffolds are designed to reside at the site of implantation for a variable period of time during which they induce the regeneration of native tissue. During this time, they also provide a template for new cells to attach, infiltrate, differentiate into appropriate phenotype and eventually restore function of the concerned tissue. Among the factors …

Tissue Engineering Cellularized Silk-Based Ligament Analogues, Scott Sell

Theses and Dissertations

The resurgence, and eventual rise to prominence in the field of tissue engineering, that electrospinning has experienced over the last decade speaks to the simplicity and adaptability of the process. Electrospinning has been used for the fabrication of tissue engineering scaffolds intended for use in nearly every part of the human body: blood vessel, cartilage, bone, skin, nerve, connective tissue, etc. Diverse as the aforementioned tissues are in both form and function, electrospinning has found a niche in the repair of each due to its capacity to consistently create non-woven structures of fibers ranging from nano-to-micron size in diameter. These …

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 …

Structural And Functional Considerations In The Design Of Collagen-Based Electrospun Scaffolds, Chantal Ayres

Theses and Dissertations

Electrospinning can be used to selectively process a variety of natural and synthetic polymers into highly porous scaffolds composed of nano-to-micron diameter fibers. This process shows great potential as a gateway to the development of physiologically relevant tissue engineering scaffolds. In this study we examine the structural and functional considerations regarding electrospun scaffolds for dermal template applications using novel quantification techniques. In order to characterize scaffold structure, a technique utilizing the fast Fourier transform was developed to systematically quantify fiber alignment and evaluate how different electrospinning parameters impact the structure and material properties of an electrospun scaffold. Gelatin was suspended …