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Biomedical Engineering and Bioengineering

Collagen

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Articles 31 - 42 of 42

Full-Text Articles in Engineering

Investigation Of A New Material For Heart Valve Tissue Engineering, Claire Brougham, Nian Shen, Allison Cudsworth, Thomas Flanagan, Stefan Jockenhoevel, Fergal O'Brien Jan 2012

Investigation Of A New Material For Heart Valve Tissue Engineering, Claire Brougham, Nian Shen, Allison Cudsworth, Thomas Flanagan, Stefan Jockenhoevel, Fergal O'Brien

Conference Papers

No abstract provided.


Quantification Of Collagen Organization Using Fractal Dimensions And Fourier Transforms, Kayt E. Frisch, Sarah E. Duenwald-Kuehl, Hirohito Kobayashi, Connie S. Chamberlain, Roderic S. Lakes, Ray Vanderby Jr. Jan 2012

Quantification Of Collagen Organization Using Fractal Dimensions And Fourier Transforms, Kayt E. Frisch, Sarah E. Duenwald-Kuehl, Hirohito Kobayashi, Connie S. Chamberlain, Roderic S. Lakes, Ray Vanderby Jr.

Faculty Publications - Biomedical, Mechanical, and Civil Engineering

Collagen fibers and fibrils that comprise tendons and ligaments are disrupted or damaged during injury. Fibrillogenesis during healing produces a matrix that is initially quite disorganized, but remodels over time to resemble, but not replicate, the original roughly parallel microstructure. Quantification of these changes is traditionally a laborious and subjective task. In this work we applied two automated techniques, fast Fourier transformation (FFT) and fractal dimension analysis (FA) to quantify the organization of collagen fibers or fibrils. Using multi-photon images of collagen fibers obtained from rat ligament we showed that for healing ligaments, FA differentiates more clearly between the different …


Optimization Of A Tri-Layered Vascular Graft: The Influence Of Cellular And Mechanical Properties, Michael Mcclure Jun 2011

Optimization Of A Tri-Layered Vascular Graft: The Influence Of Cellular And Mechanical Properties, Michael Mcclure

Theses and Dissertations

Electrospinning is a polymer processing technique which allows for the production of nano to micro size fibers and scaffolds which can be composed of numerous synthetic biodegradable materials and natural biopolymers. Natively, elastin and collagen are the main components of vascular tissue. Arranged in a tri-layered structure, they create a specific mechanical environment that can withstand the rigors of circulation. The goal of this study was to develop a mechanically ‘biomimicking’ vascular graft composed of three distinct layers through the process of electrospinning. We hypothesize that the use of bioactive agents such as elastin, collagen, and silk to supplement poly(caprolactone) …


Second-Harmonic Imaging Microscopy Of Living Cells, Paul J. Campagnola, Heather Clark, William A. Mohler, Aaron Lewis (Prof.), Leslie M. Loew Nov 2010

Second-Harmonic Imaging Microscopy Of Living Cells, Paul J. Campagnola, Heather Clark, William A. Mohler, Aaron Lewis (Prof.), Leslie M. Loew

Heather Clark

Second harmonic generation (SHG) has been developed in our laboratories as a high-resolution nonlinear optical imaging microscopy for cellular membranes and intact tissues. SHG shares many of the advantageous features for microscopy of another more established nonlinear optical technique: two-photon excited fluorescence (TPEF). Both are capable of optical sectioning to produce threedimensional images of thick specimens and both result in less photodamage to living tissue than confocal microscopy. SHG is complementary to TPEF in that it uses a different contrast mechanism and is most easily detected in the transmitted light optical path. It can be used to image membrane probes …


Lipids And Collagen Matrix Restrict The Hydraulic Permeability Within The Porous Compartment Of Adult Cortical Bone, Demin Wen, Caroline Androjna, Amit Vasanji, Joanne M. Belovich, Ronald J. Midura Mar 2010

Lipids And Collagen Matrix Restrict The Hydraulic Permeability Within The Porous Compartment Of Adult Cortical Bone, Demin Wen, Caroline Androjna, Amit Vasanji, Joanne M. Belovich, Ronald J. Midura

Chemical & Biomedical Engineering Faculty Publications

In vivo the hydraulic permeability of cortical bone influences the transport of nutrients, waste products and signaling molecules, thus influencing the metabolic functions of osteocytes and osteoblasts. In the current study two hypotheses were tested: the presence of (1) lipids and (2) collagen matrix in the porous compartment of cortical bone restricts its permeability. Our approach was to measure the radial permeability of adult canine cortical bone before and after extracting lipids with acetone-methanol, and before and after digesting collagen with bacterial collagenase. Our results showed that the permeability of adult canine cortical bone was below 4.0 × 10 …


Neomycin Enhances Glutaraldehyde Crosslinking And Glycosaminoglycan Stability In Bioprosthetic Heart Valves, Vincent Friebe Dec 2009

Neomycin Enhances Glutaraldehyde Crosslinking And Glycosaminoglycan Stability In Bioprosthetic Heart Valves, Vincent Friebe

All Theses

The native heart valve will open and close an astonishing 3 billion times in the average lifetime, implicating immense biomechanical ramifications that necessitate near-flawless structure and functional behavior. Deviations from this idyllic function as a result of heart valve disease (HVD) affect millions of individuals worldwide and result in over 275,000 heart valve replacements worldwide every year. Glutaraldehyde (GLUT) cross-linked porcine aortic heart valves, a common type of bioprosthetic heart valve (BHV), are used frequently in these valve replacement surgeries. The native valve leaflets entail a tri-composite design of type I collagen, elastin and glycosaminoglycans (GAGs), each of which are …


Design Of An Electrospun Type Ii Collagen Scaffold For Articular Cartilage Tissue Engineering, Catherine Pemble Barnes Jan 2007

Design Of An Electrospun Type Ii Collagen Scaffold For Articular Cartilage Tissue Engineering, Catherine Pemble Barnes

Theses and Dissertations

Traumatic defects in articular cartilage can lead to joint disease and disability including osteoarthritis. Because cartilage is unable to regenerate when injured, the field of tissue engineering holds promise in restoring functional tissue. In this research, type II collagen was electrospun, cross-linked, and tested as scaffolds for supporting chondrocyte growth. The mechanical, biochemical, and histological characteristics of the engineered tissue were assessed as a function of the electrospinning solution concentration (i.e. scaffold fiber diameter and pore properties) and as a function of the time in culture (evaluated at 2, 4, and 6 weeks). Fiber diameter had a linear relationship with …


Collagen Fibres Are Not Required For Initial Matrix Mineralization By Bone Cells, M. M. Hosseini, S. A. F. Peel, J. E. Davies Jan 1996

Collagen Fibres Are Not Required For Initial Matrix Mineralization By Bone Cells, M. M. Hosseini, S. A. F. Peel, J. E. Davies

Cells and Materials

Passaged primary cultures of young adult rat bone marrow cells were maintained in medium containing combinations of the supplements dexamethasone, ascorbic acid and Na-ß-glycerophosphate. The cultures were examined by both light and scanning electron microscopy (with additional energy dispersive X-ray analysis). In cultures with fully supplemented medium, an extracellular matrix formed at the culture dish surface, beneath developing bone nodules; this matrix was mineralized but collagen-fibre free and corresponded to that which we have reported previously as the equivalent of the cement line in vivo. In selected samples this interfacial, cement line, matrix was analyzed by X-ray …


A Simple Freeze Fracture Technique For Scanning Electron Microscopy Of Collagenous Biomaterials, David L. Christiansen, George Pins, Frederick H. Silver Jan 1993

A Simple Freeze Fracture Technique For Scanning Electron Microscopy Of Collagenous Biomaterials, David L. Christiansen, George Pins, Frederick H. Silver

Cells and Materials

A simple freeze fracture technique for the ultrastructural analysis of fragile collagenous biomaterials is presented. Following standard methods of preparation and dehydration, fragile biomaterials are fractured with a sharp blade attached to a modified slide hammer. The sliding mass imparts a sudden impact load on the frozen surface of the material , creating a distortion free cleavage plane across the material. More traditional methods including bending and cutting with scissors introduce artifacts indirectly associated with stress concentration produced by bending, and sample compression at the edges with cutting. The impact loading of the sample during fracture results in preservation of …


A Scanning Electron Microscope Study Of The Ultrastructural Organization Of Bone Mineral, F. B. Bagambisa, U. Joos, W. Schilli Jan 1993

A Scanning Electron Microscope Study Of The Ultrastructural Organization Of Bone Mineral, F. B. Bagambisa, U. Joos, W. Schilli

Cells and Materials

Scanning electron microscopy (SEM) was used to study samples of lamellar bone at magnifications typical for the published transmission electron micrographs, to gain more insight into the three-dimensional ultrastructure of bone mineral. Untreated (whole bone) samples allowed an assessment of the degree of mineralization. Deproteinized samples revealed the ultrastructural form and organization of bone apatite to be a function of the extent to which collagen fibers were imbibed with mineral. Numerous parallel formations reminiscent of troughs, gutters, or furrows, pierced and traversed the mineralization front. These troughs showed varying diameters identifiable with collagen fibers, and were separated from one another …


A Model For A Model: Pressure Jackets On Nude Mice With Implants Of Hypertrophic Scars, C. Ward Kischer, Jana Pindur Jan 1992

A Model For A Model: Pressure Jackets On Nude Mice With Implants Of Hypertrophic Scars, C. Ward Kischer, Jana Pindur

Cells and Materials

The hypertrophic scar, a consequence of deep surface injury, is peculiar to humankind. Subcutaneous implants of these tissues in nude mice provide a quasi - animal model for experimental use. An efficacious treatment to promote acceleration of maturation of the hypertrophic scar is controlled topical pressure produced by flexible dacron fabric wraps. Implants in the nude mouse provide a model for study of the effects of pressure. Preliminary results indicate that those implants in nude mice, responding favorably to pressure jackets, show changes consistent with those previously obtained in human studies. The collagen matrix shows reduced density and parallel layering …


Peripheral Nerve Regeneration Within Tubular Prosthesis: Effects Of Laminin And Collagen Matrices On Cellular Ingrowth, Ivar J. Kljavin, Roger D. Madison Jan 1991

Peripheral Nerve Regeneration Within Tubular Prosthesis: Effects Of Laminin And Collagen Matrices On Cellular Ingrowth, Ivar J. Kljavin, Roger D. Madison

Cells and Materials

Bridging a severed peripheral nerve with a tubular conduit, "entubulation repair" , allows manipulation of the microenvironment encountered by regenerating axons. In the present study, we placed the ends of severed mouse sciatic nerves into nonpermeable Tygon tubes to bridge a 4 mm nerve gap. The tube lumen was filled with either a collagen or laminin matrix. The matrices formed a stable 3-D structure connecting both proximal and distal stumps, and provided a scaffolding for the regenerating axons and their supporting cells. We examined with scanning electron microscopy (SEM), transmission electron microscopy (TEM) and light microscopy, the initial events of …