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Biomedical Engineering and Bioengineering Commons

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Articles 1 - 9 of 9

Full-Text Articles in Biomedical Engineering and Bioengineering

Biochemical And Biomechanical Modulation Of Nucleus Pulposus Cells Encapsulated In Novel Cellulose-Based Hydrogels, Anna T. Reza Dec 2009

Biochemical And Biomechanical Modulation Of Nucleus Pulposus Cells Encapsulated In Novel Cellulose-Based Hydrogels, Anna T. Reza

Publicly Accessible Penn Dissertations

Low back pain may be caused by a direct, acute injury or degeneration of the intervertebral disc (IVD). Intradiscal replacement of the nucleus pulposus (NP) with a tissue engineered hydrogel scaffold may provide a biologic therapy capable of restoring the structure and mechanical function of the IVD. Therefore, the global objective of this dissertation was to develop and optimize a novel, cell-laden, covlently crosslinkable carboxymethylcellulose (CMC) hydrogel construct as a functional tissue engineered NP replacement. The versatility of the photocrosslinkable CMC system was explored by examining the resultant differences in material and mechanical properties due to varying the macromer concentration ...


Differential Cellular Response To Linear And Strain Stiffening Hydrogel Substrates, Jessamine P. Winer Dec 2009

Differential Cellular Response To Linear And Strain Stiffening Hydrogel Substrates, Jessamine P. Winer

Publicly Accessible Penn Dissertations

The mechanical properties of the substrate upon which cells are cultured have been shown to influence a variety of cell properties including cell adhesion, spreading, protein expression and differentiation. The work presented here examines how the nonlinear mechanical properties of biopolymer gels affect the cellular responses to substrate stiffness. Cell spread area decreases with decreasing substrate stiffness when cells are cultured on linearly elastic polyacrylamide gels but display no spread area sensitivity when cultured on fibrin gels of various moduli. Fibrin gels, and other semiflexible biopolymer networks, exhibit strain stiffening, whereby the elastic modulus of the gel increases with increasing ...


The Electrical Properties Of Human Tissue For The Diagnosis And Treatment Of Melanoma Skin Cancer, Glenn Cameron Stante Dec 2009

The Electrical Properties Of Human Tissue For The Diagnosis And Treatment Of Melanoma Skin Cancer, Glenn Cameron Stante

Master's Theses and Project Reports

This thesis discusses the research, experimental methods, and data gathered for the investigation of a novel method for the diagnosis of melanoma skin cancer. First, a background about human skin tissue is presented. Then, a detailed description of melanoma along with current diagnosis techniques and treatment options are presented. In the experimental methods, the electrical properties of several types of tissue were analyzed, the purpose of which was to discover if a tissue type can be distinguished by its electrical properties alone. This would allow for the diagnosis of melanoma to be done by examining the electrical properties of the ...


Regression Analysis Of Fracture Toughness For Secondary Osteons Located In Human Cortical Bone, Chase A. Fetzer Oct 2009

Regression Analysis Of Fracture Toughness For Secondary Osteons Located In Human Cortical Bone, Chase A. Fetzer

Master's Theses and Project Reports

An experiment was carried out in order to locate and quantify osteon types within a sample of cortical bone taken from a human tibia. This was done using a microscope-camera assembly and the BioQuant computer software. The results of this were correlated with a previous experiment’s results on fracture toughness so that an analysis could be run on the data in order to determine the factors that most affect the value of fracture toughness of this cortical bone. Results were examined closely and the analysis repeated until the author was satisfied that the best possible model for fracture toughness ...


Assessment Of Electrospinning As An In-House Fabrication Technique For Blood Vessel Mimic Cellular Scaffolding, Colby M. James Sep 2009

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

Master's Theses and Project Reports

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 ...


Mechanical And Chemical Effects In Adhesion Of Thin Shell Structures With Applications In Wafer Bonding And Adhesion Of Living Cells, Richard M. Springman Aug 2009

Mechanical And Chemical Effects In Adhesion Of Thin Shell Structures With Applications In Wafer Bonding And Adhesion Of Living Cells, Richard M. Springman

Publicly Accessible Penn Dissertations

A theoretical model is analyzed to investigate the adhesion of thin shell structures to both rigid and deformable substrates under a variety of surface conditions. The thermodynamic forces driving the adhesive process are determined from an interfacial free energy, which is described within a classical thermodynamics framework. Deformations of the thin, elastic shells are studied using a geometrically nonlinear shell theory. Finite-range adhesive tractions, chemical segregation, substrate compliance, and substrate topography all are considered over a wide range of geometric and material parameters. Equilibrium adhesion states are characterized by a shell flatness parameter, the contact radius, and the adhesive and ...


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 Jun 2009

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 and Project Reports

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 ...


Development Of An In-Vitro Tissue Engineered Blood Vessel Mimic Using Human Large Vessel Cell Sources, Dimitri E. Delagrammaticas May 2009

Development Of An In-Vitro Tissue Engineered Blood Vessel Mimic Using Human Large Vessel Cell Sources, Dimitri E. Delagrammaticas

Master's Theses and Project Reports

Tissue engineering is an emerging field that offers novel and unmatched potential medical therapies and treatments. While the vast aim of tissue engineering endeavors is to provide clinically implantable constructs, secondary applications have been developed to utilize tissue-engineered constructs for in-vitro evaluation of devices and therapies. Specifically, in-vitro blood vessel mimics (BVM) have been developed to create a bench-top blood vessel model using human cells that can be used to test and evaluate vascular disease treatments and intravascular devices. Previous BVM work has used fat derived human microvascular endothelial cells (EC) sodded on an ePTFE scaffold. To create a more ...


Nano-Mechanics Of Cartilage Glycosaminoglycans Using Molecular Dynamics Methods, Kevin Neil Hendrickson Jan 2009

Nano-Mechanics Of Cartilage Glycosaminoglycans Using Molecular Dynamics Methods, Kevin Neil Hendrickson

Master's Theses and Project Reports

Articular Cartilage (AC) is the main load carrying material in synovial joints {Hamerman, 1962} and degeneration of AC can cause pain in the form of arthritis. Current work is centered on the method of replacing damaged cartilage inside the body (in vivo) with tissue engineered outside the body (ex vivo) {Temenoff, 2000}. In order to engineer tissue ex vivo similar to the native tissue in structure and function there must be a comprehensive understanding of the mechanical properties of AC. This work focuses on the study of glycosaminoglycans (GAGs), a molecule known to be primarily responsible for the compressive stiffness ...