Laser Speckle Rheology for evaluating the viscoelastic properties of hydrogel scaffolds
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Laser speckle.pdf
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Author(s)
Hajjarian, Zeinab
Nia, Hadi Tavakoli
Ahn, Shawn
Nadkarni, Seemantini K.
Grodzinsky, Alan J
Jain, Rakesh Kumar
Date Issued
December 2016
Journal
Scientific Reports
Publisher
Nature Publishing Group
Citation
Hajjarian, Zeinab, Hadi Tavakoli Nia, Shawn Ahn, Alan J. Grodzinsky, Rakesh K. Jain, and Seemantini K. Nadkarni. “Laser Speckle Rheology for Evaluating the Viscoelastic Properties of Hydrogel Scaffolds.” Scientific Reports 6, no. 1 (December 2016).
Version
Final published version
Abstract
Natural and synthetic hydrogel scaffolds exhibit distinct viscoelastic properties at various length scales and deformation rates. Laser Speckle Rheology (LSR) offers a novel, non-contact optical approach for evaluating the frequency-dependent viscoelastic properties of hydrogels. In LSR, a coherent laser beam illuminates the specimen and a high-speed camera acquires the time-varying speckle images. Cross-correlation analysis of frames returns the speckle intensity autocorrelation function, g[subscript 2](t), from which the frequency-dependent viscoelastic modulus, G*(ω), is deduced. Here, we establish the capability of LSR for evaluating the viscoelastic properties of hydrogels over a large range of moduli, using conventional mechanical rheometry and atomic force microscopy (AFM)-based indentation as reference-standards. Results demonstrate a strong correlation between |G*(ω)| values measured by LSR and mechanical rheometry (r = 0.95, p < 10−[superscript 9]), and z-test analysis reports that moduli values measured by the two methods are identical (p > 0.08) over a large range (47 Pa – 36 kPa). In addition, |G*(ω)| values measured by LSR correlate well with indentation moduli, E, reported by AFM (r = 0.92, p < 10−[superscript 7]). Further, spatially-resolved moduli measurements in micro-patterned substrates demonstrate that LSR combines the strengths of conventional rheology and micro-indentation in assessing hydrogel viscoelastic properties at multiple frequencies and small length-scales.
MIT Department
Harvard University--MIT Division of Health Sciences and Technology
Massachusetts Institute of Technology. Center for Biomedical Engineering
Massachusetts Institute of Technology. Department of Biological Engineering
Massachusetts Institute of Technology. Department of Electrical Engineering and Computer Science
Massachusetts Institute of Technology. Department of Mechanical Engineering
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Creative Commons Attribution 4.0 International License
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DOI of Published Version
https://doi.org/10.1038/srep37949
