1. Cell Adhesion Matt Tanke Will Howerton Stewart Bewley Jeff Mills

2. Cell Adhesion Measurement Device  Cell sits between two plates  One plate fixed, one plate attached to linear spring  Actuator pulls spring into tension

3. Adhesion of Cell  Cell will have a smooth outer membrane or flagellum  Both exhibit non-linear cell/plate separation Flagellum Smooth Membrane http://library.thinkquest.org/16985/cellmain.htm http://fig.cox.miami.edu/Faculty/Dana/105F00_4.html

4. Adhesion of Cell

5. Current Design: Optical Tweezers  Nm displacement  pN force  Glass bead dependent

6. Scratch Drive  μN forces  500 μm displacement  Difficult to model

7. Nano-tractor  40 nm step size  Moves at 3 mm/s  Stalls when 2.5 mN max tangential force is reached

8. How it works

9. Accuracy

10. SUMMiT V Process Flow  Conformal Deposition  Planar Depostion  Dry Etch  Wet Etch  Release Etch

11. Diagram and Variables  6 variables: D 2, P 2, k s, D 1, P 1, k c  2 equations can be derived: P 1 = D 1 *(k c + k s ) – D 2 *k s P 2 = k s *(D 2 – D 1 ) D2D2 P2P2 ksks kckc D1D1 P1P1  D 2 is controlled by nano-tractor  P 2 is the force needed for nano-tractor  P 1 is the force needed to pull the cell  D 1 is the displacement of the cell  k c is the spring constant of the cell  k s is the spring constant of the spring

12. Assumptions  P2 is not needed  Assumptions need to be made for other variables in order to find values for k’s D2D2 P2P2 ksks kckc D1D1 P1P1 Finding k c  Assumptions Cell is a cylinder Diameter equals length Diameter roughly 10-50 um  Calculation kc = E*pi*d/4 kc =.0076-.0393 N/m

13. Finding ks D2D2 P2P2 ksks kckc D1D1 P1P1 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

14. Overview of Range Case K s (N/m) K c (N/m) P 1 (nN) D 1 (um) D 2 (um) # of Increments Most Elastic Cell.0246.007610022.025.0100 Least Elastic Cell.0246.039311.744.7420

15. Spring Dimensions  2 double cantilever beams  ks = E*t*(w/l) 3 w = 2.25 um l = 785 um T = 7 um

16. Results

17. Thank You Questions?