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Cell Adhesion. Matt Tanke Will Howerton Stewart Bewley Jeff Mills. Cell Adhesion Measurement Device. Cell sits between two plates One plate fixed, one plate attached to linear spring Actuator pulls spring into tension. Adhesion of Cell. Cell will have a smooth outer membrane or flagellum
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Cell Adhesion Matt Tanke Will Howerton Stewart Bewley Jeff Mills
Cell Adhesion Measurement Device • Cell sits between two plates • One plate fixed, one plate attached to linear spring • Actuator pulls spring into tension
Adhesion of Cell • Cell will have a smooth outer membrane or flagellum • Both exhibit non-linear cell/plate separation Flagellum Smooth Membrane http://fig.cox.miami.edu/Faculty/Dana/105F00_4.html http://library.thinkquest.org/16985/cellmain.htm
Current Design: Optical Tweezers • Nm displacement • pN force • Glass bead dependent
Scratch Drive • μN forces • 500 μm displacement • Difficult to model
Nano-tractor • 40 nm step size • Moves at 3 mm/s • Stalls when 2.5 mN max tangential force is reached
SUMMiT V Process Flow • Conformal Deposition • Planar Depostion • Dry Etch • Wet Etch • Release Etch
Diagram and Variables ks kc D1 D2 P2 P1 • 6 variables: D2, P2, ks, D1, P1, kc • 2 equations can be derived: • P1 = D1*(kc + ks) – D2*ks • P2 = ks*(D2 – D1) • kc is the spring constant of the cell • ks is the spring constant of the spring • D2 is controlled by nano-tractor • P2 is the force needed for nano-tractor • P1 is the force needed to pull the cell • D1 is the displacement of the cell
P2 is not needed Assumptions need to be made for other variables in order to find values for k’s Finding kc Assumptions Cell is a cylinder Diameter equals length Diameter roughly 10-50 um Calculation kc = E*pi*d/4 kc = .0076-.0393 N/m Assumptions ks kc D1 D2 P2 P1
Assumptions P1 = 1-100 nN D2 = 11 um – ls + D1 Due to limit of optical measuring tool Assume ls = 8 um Made spreadsheet ks = 0.0246 N/m Verification Find increment for D2 that works for range Must be greater than 40 nm Selected 250 nm Check if increment will be detectable Finding ks ks kc D1 D2 P2 P1
Spring Dimensions • 2 double cantilever beams • ks = E*t*(w/l)3 • w = 2.25 um • l = 785 um • T = 7 um
Thank You Questions?