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