Magnetic%20Tweezer%20System%20Development

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Magnetic Tweezer System Development
Probing mechanical properties across multiple
scales

• Jason Sherfey
• Senior BME, Vanderbilt University

Advisor Dr. Franz Baudenbacher
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Force displacement measurements on magnetic beads
linked to the cell surface through E-Cadherin
Fit to Mechanical Analog
Extract Model parameter
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Force-Displacement Curves MDCK cells
P120 Knockout
Wild-type
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Viscosity (Pa-s-m)
N 10
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Elasticity (Pa-m)
N 10
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Relaxation Time (s)
N 10
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No significant difference in WT KO Viscosities
WT Elasticity is significantly larger than KO
WT Relaxation Time is significantly faster than KO
N 10 cells
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Conclusions

• The stiffness and relaxation time constants are
  significantly different in p120 knockout and
  wild-type MDCK cells.
• 2. The stiffness decreases relaxation time
  slows down when p120 expression is reduced in
  MDCK cells.

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Strain Hardening
Stiffness (Pa-m)

• The stiffness of the adhesion protein linker
  system increases when stress is repeatedly
  applied.

Pull  Wild-type Cell
1 0.0132
2 0.0152
3 0.0193
4 0.0249
  Knockout Cell
1 0.0051
2 0.0063
3 0.0081