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Preparation of 3D Collagen Gels and Microchannels for the Study of 3D Interactions In Vivo
Published on: May 9, 2016
Predicting bulk mechanical properties of cellularized collagen gels using multiphoton microscopy.
C B Raub1, A J Putnam, B J Tromberg
1Department of Biomedical Engineering, University of California, Irvine, CA 92697-2730, USA.
Acta Biomaterialia
|July 13, 2010
Summary
Multiphoton microscopy reveals how collagen gel microstructure, including cellularity and crosslinking, dictates mechanical properties. Image analysis parameters can predict gel stiffness, crucial for tissue engineering applications.
Area of Science:
- Biomaterials Science
- Tissue Engineering
- Biophysics
Background:
- Cellularized collagen gels are vital tissue engineering models, but their microstructural determinants of mechanical properties remain unclear.
- Multiphoton microscopy (MPM) offers non-invasive imaging of collagen microstructure, cellularity, and crosslinking within these gels.
Purpose of the Study:
- To identify image parameters from MPM that robustly characterize microstructural features influencing the bulk elastic modulus of collagen gels.
- To correlate microstructural parameters with the mechanical properties (Young's modulus) of acellular and cellularized collagen hydrogels.
Main Methods:
- Serial multiphoton microscopy (MPM) and mechanical testing were performed on acellular and cellularized collagen hydrogels.
- Gels were analyzed before and after glutaraldehyde crosslinking, and over a 16-day contraction period.
- Image parameters derived from second harmonic generation (SHG) and two-photon fluorescence (TPF) signals were quantified.
Main Results:
- Young's modulus (E) of acellular gels showed power-law concentration dependence (exponents 2.1-2.2).
- Cellularized gels exhibited different concentration-dependent exponents (0.7 uncrosslinked, 1.1 crosslinked) and higher stiffness.
- SHG and TPF image skewness and speckle contrast significantly predicted Young's modulus (R² up to 0.83) in cellularized gels.
Conclusions:
- Microstructural image parameters, specifically SHG and TPF skewness and speckle contrast, can accurately predict the elastic modulus of cellularized collagen gels.
- These image parameters capture essential information on collagen fiber, cell density, and crosslinking, correlating microstructure with bulk mechanical behavior.
- Findings advance understanding of collagen gel mechanics, crucial for designing biomimetic materials in tissue engineering.
