Slide-Set-7-BAF-Scaffolds-SFB-2002

Slide-Set-7-BAF-Scaffolds-SFB-2002 - Slide Set #7 -...

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Unformatted text preview: Slide Set #7 - Bioactive FiberSlide Based Scaffolds in Bone Based Replacement Tissue Engineering Engineering CA Seegert1, BM Hatcher1, AB Brennan1,2 CA Biomedical Engineering, University of Florida, Biomedical Gainesville, FL 32611 Gainesville, 2 Materials Science and Engineering, University of Materials Florida, Gainesville, FL 32611 Florida, 1 Bone Replacement and Reconstruction and • Autologous bone – Limited supply – Donor site Morbidity • Allogenic bone – – Incorporation Ltd. Pathogenic Pot. • Synthetics – Porosity – Stiffness Properties Fiber Based Scaffolds Fiber • Synthetic Synthetic • Mechanical Mechanical Flexibility Flexibility • Superior Porosity/ Superior Diffusion properties. Diffusion 77S Discontinuous Bioactive Glass Fibers Glass 20µm • Sol Gel Synthesis • Air Spraying Air Technique Technique η ~ 2 Pa-s Pa-s – 3.45 x 106 Pa • Sintered at 900°C °C for 3 hrs for 10µm Culture Methods Culture • Rat Mesenchymal Rat Stem Cells (RMSC) Manitoupolos et al. 1988 1988 – 15% FBS – 50 µ g/ml ascorbic 50 g/ml acid – 10 mM β -glycero10 phosphate – No Dexamethasone 21 day Von Kossa Stained RMSC culture Multilayering Effects Multilayering • Discontinuous Discontinuous bioactive glass fibers fibers • 6 days Bar = ~150 µm BG Fiber SEM BG • JEOL 6400 JEOL scanning electron microscope microscope • Preparation: – 3% Glutaraldehyde – Serial EtOH Serial Dehydration Dehydration – Pd/Au ~20 Å Bars ~100 µm Bridging Phenomenon Bridging 50µm • Bioactive Glass Bioactive Fibers (6 days) Fibers • Multicellular Multicellular Bridging > 70 µm µm • • Floor-Fiber Fiber-Fiber 20µm Polymer Fiber Bridging Polymer 50µm • 4-0 Ethilon™ Nylon 4-0 Sutures (Day 12). Sutures • 7-0 Maxon™ Polyglyconate Polyglyconate Sutures (Day 13) (Day 20µm Bridging on Polystyrene (Day 7) (Day 250µm Flask Wall Flask Floor Bridging on Polystyrene (Day 8) (Day 250µm Bridging on Polystyrene (Day 10) (Day 250µm 250µm Bridging on Polystyrene (Day 11) (Day 250µm Bridging on Stainless Steel Bridging Day 10 Day 12 Day 15 Bar ~150µm Day 18 Day 23 Sequence of Events Sequence Theoretical Explanation Theoretical • Adhesion-⇑ Proliferation ⇑ Mineralization Mineralization – Roughness/Topography (Ti1, HA2, PS3) – Chemistry/Surface Energy (Pr. Mediated) • Mechanics-. – Cl- Stretch Receptors &Topography4 – Stretch ⇒ Differentiation & ECM Orientation5 Stretch • Architecture- Mechanical Advantage – – Bridging Effects Spacing Distance Cell Based Tension Generation is Required for Proper Cell Function Proliferation Experiments Proliferation • Fibers Packed in Fibers Constructs Constructs • Increased Mass/ Increased Constant Volume Constant ⇑ Density = ⇓ Spacing Spacing • Beckman Coulter Beckman Multisizer III Multisizer – 500 µ l analytical vol. 500 – Isoton II diluent 9.17 ± 0.05 mm 1.85 ± 0.09 mm Analysis Analysis Rat MSC Proliferation on 77S Bioactive Fiber Scaffolds 2.75E+06 2.50E+06 Cellular Concentration (Cells/mL) • Seeding Density Seeding 1.10 ± 0.07 x 105 0.07 Cells/mL Cells/mL • 9 days in culture • [Cell]/ ml vs. [Cell]/ % Porosity Porosity 2.25E+06 2.00E+06 1.75E+06 1.50E+06 1.25E+06 1.00E+06 100.00 95.00 90.00 85.00 Porosity (%) 1 way ANOVA P<0.05 80.00 Conclusions Conclusions • BG Fiber Matrix Fosters Proliferation BG Apparently Through Bridging. Apparently • Fiber Density & Spacing Influence Fiber RMSC Proliferation in this System. RMSC • Overall: Tension Development Seems to be Integral in Proper Cell Function. to Acknowledgements Acknowledgements • • • • Dr. Colin Sumners & Group at UFBI Brennan Research Group Funding from the Whitaker Foundation Office of Naval Research (US Navy Office N0014-99-1-0795) References References 1) Singhvi, R., Stephanoupolos, G., Wang, D.. Review: Effects of 1) Substratum Morphology on Cell Physiology. Biotechnology and Bioengineering, 1994, 43: 764-771. Bioengineering, 2) Deligianni, D., Katsala, N., Koutsoukos, P., Missirlis, Y.. Effect of 2) Surface Roughness of Hydroxyapatite on Human Bone Marrow Cell Adhesion , Proliferation, Differentiation and Detachment Strength. Biomaterials, 2001, 22: 87-96. Biomaterials, 3) Gomi, K., Davies, J.. Guided Bone Tissue Elaboration by Osteogenic 3) Cells in vitro. Journal of Biomedical Materials Research, 1993, 27: 429Cells 431. 4) Tobasnick, G., Curti, A.. Chloride Channels and the Reactions of Cells 4) to Topography. European Cells and Materials, 2001, 2: 49-61. to 5) Altman, G., Horan, R., Martin, I., Farhadi, J., Stark, P., Volloch, V., 5) Vunjak-Novakovic, G., Richmond, J., Kaplan, D.. Cell Differentiation by Mechanical Stress. The FASEB Journal, 2002, 16: 270-272. The ...
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This note was uploaded on 09/18/2011 for the course EMA 4760 taught by Professor Staff during the Spring '10 term at University of Florida.

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