Focal Adhesion Mechanotransduction: Focal Adhesion - - PowerPoint PPT Presentation

▶
focal adhesion mechanotransduction focal adhesion
SMART_READER_LITE
LIVE PREVIEW

Focal Adhesion Mechanotransduction: Focal Adhesion - - PowerPoint PPT Presentation

Dec 25, 2022 267 likes •397 views

The 5 th Korean-US NanoForum: Nanobiotechnology. Jeju Island, April 17 th -19 th , 2008 Focal Adhesion Mechanotransduction: Focal Adhesion Mechanotransduction: Cellular Response to Nanoscale Cellular Response to Nanoscale Mechanical Factors

slide-1
SLIDE 1

The 5th Korean-US NanoForum: Nanobiotechnology. Jeju Island, April 17th-19th, 2008

Focal Adhesion Mechanotransduction: Focal Adhesion Mechanotransduction: Cellular Response to Nanoscale Cellular Response to Nanoscale Mechanical Factors Mechanical Factors

Nathan J. Sniadecki, Ph.D.

Mechanical Engineering Department University of Washington Seattle, Washington

slide-2
SLIDE 2

Mechanotransduction at Focal Adhesions Mechanotransduction at Focal Adhesions

Focal adhesions are force sensitive integrin-receptor complexes (100 nm – 1 μm).

Extracellular Matrix (ECM) Cell Actin Myosin

Extracellular matrix (ECM)

F

  • c

a l A d h e s i

  • n

( F A )

Structural proteins Structural proteins link integrins to actin to develop traction force for cellular migration or contraction Signaling proteins Signaling proteins activated with integrin- matrix binding and force

vin vin tal tal FAK tal p130 Actin Integrins Integrins α-Act FAK Src pax

Traction Force External Force

Traction forces or external forces are transduced into biological signals that can regulate cell function

slide-3
SLIDE 3

Traction Force Sensor Array Traction Force Sensor Array

20 nN

DAPI Actin PDMS Vinculin

10 μm

Arrays of flexible microposts to measure traction forces Made with soft lithography of polydimethlysiloxane (PDMS) 3-μm diameter, 10-μm height microposts

slide-4
SLIDE 4

Magnetic Microposts Magnetic Microposts

Sensor and Actuator System Sensor and Actuator System

  • Measure traction forces with microposts
  • Apply forces with magnetic nanowires

Cobalt Nanowires Cobalt Nanowires

  • 300 nm diameter, 5-7 μm long
  • High magnetic moment (µ) along long axis

Nanowire

Nanowires

N.J. Sniadecki, et al., PNAS, 2007, 104:114553-8 N.J. Sniadecki, et al., Rev Sci Instr, 2008, 79, 044302

2 2

3 ( ) 2( )

w Mag w w

L L F L L L L τ + = + +

d 3

3 E δ δ 64L

tr

F K π   = =     B µ ⋅ =

⊥

τ

slide-5
SLIDE 5

Magnetic Nanowires Magnetic Nanowires

2e-

Co2+ Co Co2+ Co2+ Co2+

Co2+(aq) + 2e- → Co(s) 2 µm

Template

Cobalt Electrodeposition Vibrating Sample Magnetometer

N.J. Sniadecki, et al., PNAS, 2007, 104:114553-8 N.J. Sniadecki, et al., Rev Sci Instr, 2008, 79, 044302

slide-6
SLIDE 6

Fabrication Fabrication

  • 1. Lithography

Nanowires magnetically embedded into PDMS mold

  • 4. Deposit Nanowires
  • 2. Develop
  • 5. Encase in PDMS
  • 3. Cast in PDMS
  • 6. Release

SEM Image EDS Measurement

N.J. Sniadecki, et al., PNAS, 2007, 104:114553-8 N.J. Sniadecki, et al., Rev Sci Instr, 2008, 79, 044302

slide-7
SLIDE 7

Magnetic Stimulation Magnetic Stimulation

N.J. Sniadecki, et al., PNAS, 2007, 104:114553-8

Magnetic actuation for external force Focal adhesion protein recruitment Stimulation relaxes traction forces

slide-8
SLIDE 8

Spatial Response Spatial Response

Jump Jump Gradual Gradual Control Control

Magnetic Post

Relaxation occurs at remote sites along cell periphery but not at interior posts Binomial Analysis: Edge posts have significant loss versus interior posts (p<0.05) Post local to magnetic posts have no significant difference to distal posts (p>0.25)

N.J. Sniadecki, et al., PNAS, 2007, 104:114553-8

slide-9
SLIDE 9

Nanoposts Nanoposts

Sloped-wall cantilever

High Spatial Resolution of Traction Forces

830 nm dia, 3.3 μm tal 16 nN/μm 830 nm dia, 3.0 μm tall 28 nN/μm 670 nm dia, 3.3 μm tal 8 nN/μm

M.T. Yang, N.J. Sniadecki, C.S. Chen, Adv Mat, 2007, 104:114553-8

slide-10
SLIDE 10

SUPPORT:

National Institutes of Health National Science Foundation The Hartwell Foundation UW Royalty Research Fund

Nathan J. Sniadecki Sangyoon Han Aimi Ahmad Shukri Collaborators: Christopher S. Chen (UPenn) Daniel H. Reich (JHU)

Acknowledgements Acknowledgements

slide-11
SLIDE 11
slide-12
SLIDE 12
  • J. L. Tan, et al., Proc. Nat. Acad. Sci., 2003, 100:1484-1489
  • C. A. Lemmon, et al., Mech. & Chem. Biosystems., 2005, 2(1) 1-16

Micropost Force Sensors Micropost Force Sensors

4 3

3 Ed F 64L K π δ δ   = =    

F … Cellular Force K … Spring Stiffness (32 nN/μm) δ … Displacement E … Elasticity Modulus of PDMS d … Post diameter (3 μm dia) L … Post Length (10 μm)

Posts deflects as simple cantilever springs:

Microcontact printing: No adhesion blocking: Adhesion only on tips: Post Array:

Fibronectin

Measurements:

PEO PPO