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Journal of Biomedical Optics • Open Access

Molecular basis for optical clearing of collagenous tissues
Author(s): Jason M. Hirshburg; Krishnakumar M. Ravikumar; Wonmuk Hwang; Alvin T. Yeh

Paper Abstract

Molecular interactions of optical clearing agents were investigated using a combination of molecular dynamics (MD) simulations and optical spectroscopy. For a series of sugar alcohols with low to high optical clearing potential, Raman spectroscopy and integrating sphere measurements were used to quantitatively characterize tissue water loss and reduction in light scattering following agent exposures. The rate of tissue water loss was found to correlate with agent optical clearing potential, but equivalent tissue optical clearing was measured in native and fixed tissue in vitro, given long-enough exposure times to the polyol series. MD simulations showed that the rate of tissue optical clearing correlated with the preferential formation of hydrogen bond bridges between agent and collagen. Hydrogen bond bridge formation disrupts the collagen hydration layer and facilitates replacement by a chemical agent to homogenize tissue refractive index. However, the reduction in tissue light scattering did not correlate with the agent index of refraction. Our results suggest that a necessary property of optical clearing agents is hyperosmolarity to tissue, but that the most effective agents with the highest rates of optical clearing are a subset with the highest collagen solubilities.

Paper Details

Date Published: 1 September 2010
PDF: 8 pages
J. Biomed. Opt. 15(5) 055002 doi: 10.1117/1.3484748
Published in: Journal of Biomedical Optics Volume 15, Issue 5
Show Author Affiliations
Jason M. Hirshburg, Texas A&M Univ. (United States)
Krishnakumar M. Ravikumar, Texas A&M Univ. (United States)
Wonmuk Hwang, Texas A&M Univ. (United States)
Alvin T. Yeh, Texas A&M Univ. (United States)

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