Transcript Document
Force Microscopy of
Nonadherent Cells:
A Comparison of Leukemia
Cell Deformability
by Rosenbluth, Lam & Fletcher
Sangjin Ryu
Department of Mechanical Engineering
Background
Better knowledge of mechanical property
changes in leukemia cells
→ Improved understanding of leukemia
Atomic force microscopy (AFM) to
measure the stiffness of cells
→ Lab module 2: Elastic modulus
Nonadhesive cells tend to slip from the
cantilever tip under an applied load
How to Fix Leukemia Cells?
Sticky surface
Trapping within Millipore filters
Micropipette aspiration
Microfabricated well
Rosenbuth, Lam & Fletcher 2006 Biophys. J.
Experiments
Cells for investigation
Acute
myeloid leukemia cell: HL60 cell
Acute lymphoid leukemia cell: Jurkat cell
Normal leukocyte: Human neutrophil
Tips for investigation
Pyramid
AFM tip
Sphere indenter
Mechanical Models
Hertzian model: Elastic modulus
2
4
F
1
2
3E tan
Liquid droplet model: Membrane tension
8TS 2 1 cos
d
k Rc
S
Results
Hertzian model is better
Stiffness: HL60>Jurkat>Neutrophil