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Prevascularized Acellular Construct for Tissue Engineering. Ryan Nagao Apr 9, 2010. Objective. Create a construct that can be connected to the host vascular system for rapid anastomosis and tissue survival for large defects. Current Solutions to Vascularization.
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PrevascularizedAcellular Construct for Tissue Engineering Ryan Nagao Apr 9, 2010
Objective • Create a construct that can be connected to the host vascular system for rapid anastomosis and tissue survival for large defects
Current Solutions to Vascularization Jain RK., et al. Nat Biotechnol, 2005
PrevascularizingAcellular Tissue in vitro Decellularization EC cell seeding Excision Perfusion culture
Specific Aim 1 • Specific Aim 1 – Preservation of intricate microvasculature using decellularization • Evaluate the scaffold composition for cellularity and ECM components against unmodified tissue from the same source • Implantation subcutaneously to evaluate immunogenicity in vivo
Aim 1: Experimental Strategy neurophilosophy.files.wordpress.com/ Tom WJ., et al. IEEE T Med Imaging, 2008
Preliminary Research—Presence of CD-31 Following Decell Low concentration DAPI CD-31 High concentration Acell Lung Fresh Lung
Preliminary Research—Preservation of ECM Proteins Following High Concentration Decell DAPI FN LN Acell Lung Fresh Lung
Speckle Imaging • Gives relative flow velocities • Used by Dunn’s lab to visualize occlusions and opened pathways in the brain • Modify resolution and depth of field using different objectives • I can determine the patency following decellularization using this method Tom WJ., et al. IEEE T Med Imaging, 2008
Fractal Analysis • Way to measure geometries that are not of integer order • Describes self similarity • Describes complexity http://www.proetcontra.com/wp-content/uploads/fractal_geometry.jpg
What Am I Talking About? • Consider • Increasing L by 2 results in 4 similar objects • Follows a power law • Dim=2, thus a triangle is considered a 2 dimensional figure yay! Length = L Length = 2L N= scaledim 4= 2dim
Calculating a Fractal Dimension • Now consider • 2dim=3 • Dim=ln(3)/ln(2) = 1.58 http://scienceblogs.com/goodmath/2007/08/fractal_dimension_1.php
Fractal Dimensions are Present in Nature • Trees, coastlines, and vascular beds have all been characterized using fractal analysis • Vessels, Df = ~1.7 • Capillaries, Df = ~2 • Tumors, Df = ~1.9 • Implement a box-counting algorithm on a skeletonized figure • This yields regressions lines whose slope will give the fractal dimension of your figure • Can also get information about branching from the skeletonized image through an analysis algorithm
Perfusion System Calculations • Shear calculation • My culture system *Inoguchi H., et al. Biomaterials, 2006
Flow System Set-up • Flow rates will be measured real-time using Doppler ultrasound • Shear rates can be determined based off of flow rates • Side project could determine the benefits that acellular vascular ECM imparts on endothelial cell alignment 1 mm Pressure control valve Reservoir T T Incubator