Perfused Bioreactor with MatrixEnabled Capillary Scaffold MECS Team
Perfused Bioreactor with Matrix-Enabled Capillary Scaffold (MECS) Team Members: Allyson Fry Bryan Gorman Jonathan Lin William Wong Advisor: Dr. John P. Wikswo A continuation from 2004 -2005 (Barnett, Garrett, Harvill, Mayer, Mc. Clintock)
Objective Design a tissue engineering scaffold and supporting microfluidic control system to guide the development of a network of capillary tubes in vitro.
Introduction l l Bioreactor Capillary network Matrix-Enabled Capillary Scaffold (MECS) Perfusion
Motivation l Simplified model for disease research l Human system l Control at many levels l Variety of uses http: //www. kids 4 research. org/mouse%20 in%20 hand%20 facing%20 left. jpg
Martins-Green -Overall transwell culture -Culture images from Martins-Green -Cross sectional image Dec. 05 showing capillaries a a
Bioreactor Design Supply Network Support Filter Collagen Capillary Scaffold Collagen Support Filter Supply Network
Fractal pattern of vasculature Vasculature of Mouse Ear (L. Nanney) Representation of Chick Chorioallantoic Membrane (CAM) Vasculature
Matrix Enabled Capillary Scaffold (MECS) Designs 1. PDMS ‘Eggcrate’ Design 2. Collagen Micromold Design Both designs fabricated angioconductive potential assessed!
PDMS Eggcrate Scaffold 1 st layer Exposure time 2 nd layer Exposure time Height 35 -um 1. 960 min. 15 -um 0. 714 min. 69. 75 um
Cross-Section 50 um 20 um 70 um 50 um 20 um Thick PDMS eggcrate scaffold 190 um 290 um
Integrate pumping system for Eggcrate scaffold Fluid in Fluid out. Matrix Enabled Capillary Scaffold (MECS) Challenge: Fabrication of three layer SU-8 needed.
Overall Superstructure
Overall fluidics
Pumps and Lab. VIEW
Main Control Program Graphs p. H ranges PID coefficients p. H sensor settings Pump settings Histories of graph values
Proportional Integral Differential (PID) Control Equation C(t) = P*e(t) + I*∫e(t) + D*d[e(t)]/dt Components l P – compensates for immediate error l l I – compensates for steady-state error l l Allows for quick response to changes Slowly steers persistent error to 0 D – compensates for trends in error l Increases damping of system response
Project Goals l l l Model a complete microvascular network Support cellular processes Allow evaluation of molecular mechanisms Provide environment for endothelial cell differentiation Facilitate formation of stable tubular structures Support a flow of perfusate
Collaborators Dmitry Markov, Ph. D Research advisor in microfabrication Lisa Mc. Cawley, Ph. D Research advisor in tissue culture Philip Samson Research advisor in microfabrication Jason Greene Graduate student working on related bioreactor projects Advice on interfacing pumps with computer Clean room manager Walter Georgescu Ron Resiserer
References l l l Martins-Green M, Li Q, Yao M. A New Generation Organ Culture Arising from Cross-Talk Between Primary Human Cell Types. Unpublished. Nanney, Lillian et al. Unpublished research. Tang MD et al. Fabrication of collagen gels that contain patterned micrometerscale cavities. Adv. Mater, 2004.
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