data blitz eric spivey 5 may 2010. background: using pulsed laser-generated multiphoton excitation...
TRANSCRIPT
Data Blitz
Eric Spivey5 May 2010
Background: Using pulsed laser-generated multiphoton excitation to fabricate micron scale hydrogel matrices from biopolymer solutions.
Motivation: Use this method to fabricate cell scaffolds for neural tissue engineering applications.
Goal: Fabricate hydrogel microstructures with tunable functional and mechanical properties.
Focused, pulsed laser
Biopolymer Solution
Biopolymer Hydrogel Matrix Microscope Objective
Hertz Model
RadiusR
Force = F
Displacement = d
• Can calculate Young’s Modulus with F, R and d,• Assume:
Poisson’s ratio is 0.5 and Substrate measured is infinitely thick
• Corrections exist for non-infinite substrates
Force-indentation
Dwell time measurements
Dwell Time Measurements
Dwell Time Measurements
Finite Element Modeling
From Dintwa et. al. Granular Matter. 2008
Implications
Protein Cantilevers
From Khirpin et. al. Soft Matter. 2010 (in press)
BSA/GMHA Cantilevers
Next
• Validate system using PDMS standard – initial attempts with high modulus sample did not work
• Use lower force, lower strain system (low spring constant, large R) to take measurements (reduce high strain systemic error)
• Incorporate high-strain systemic error estimation into current model
• Further explore “protein cantilever” method
Fabricated Microstructures
5 µm
5 µm
Other
Repeatability
Day 3
Day 1
1 mW 2 mW 3 mW 4 mW
80 µm/sec