Characterizing matrix remodeling in collagen gels using optical coherence tomography

David Levitz, Monica T. Hinds, Stephen R. Hanson, Steven L. Jacques

Research output: Chapter in Book/Report/Conference proceedingConference contribution

2 Scopus citations

Abstract

Optical coherence tomography (OCT) has shown promise at non-destructively characterizing engineered tissues such as collagen gels. However, as the collagen gels develop, the OCT images lose contrast of structures as the gels develop, making visual assessment difficult. Our group proposed quantitatively characterizing these gels by fitting the optical properties from the OCT signals. In this paper, we imaged collagen gels seeded with smooth muscle cells (SMCs) over a 5-day period and used the data to measure their optical properties. Our results showed that over time, the reflectivity of the samples increased 10-fold, corresponding to a decrease in anisotropy factor g, without much change in the scattering coefficient μs. Overall, the optical properties appeared to be dominated by scattering from the collagen matrix, not the cells. However, SMCs remodeled the collagen matrix, and this collagen remodeling by the cells is what causes the observed changes in optical properties. Moreover, the data showed that the optical properties were sensitive to the activity of matrix metalloproteinases (MMPs), enzymes that break down local collagen fibrils into smaller fragments. Blocking MMPs in the SMC gels greatly impeded both the remodeling process and change in optical properties at day 5. Treating day 1 acellular gels with MMP-8 for 3 hr managed to partially reproduce the remodeling observed in SMC gels at day 5. Altogether, we conclude that matrix remodeling in general, and MMPs specifically, greatly affect the local optical properties of the sample, and OCT is a unique tool that can assess MMP activity in collagen gels both non-destructively and label free.

Original languageEnglish (US)
Title of host publicationOptical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIV
DOIs
StatePublished - May 3 2010
EventOptical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIV - San Francisco, CA, United States
Duration: Jan 25 2010Jan 27 2010

Publication series

NameProgress in Biomedical Optics and Imaging - Proceedings of SPIE
Volume7554
ISSN (Print)1605-7422

Other

OtherOptical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIV
CountryUnited States
CitySan Francisco, CA
Period1/25/101/27/10

Keywords

  • Anisotropy
  • Cells
  • Collagen
  • Optical coherence tomography
  • Optical properties
  • Scattering
  • Tissue engineering

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Biomaterials
  • Atomic and Molecular Physics, and Optics
  • Radiology Nuclear Medicine and imaging

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  • Cite this

    Levitz, D., Hinds, M. T., Hanson, S. R., & Jacques, S. L. (2010). Characterizing matrix remodeling in collagen gels using optical coherence tomography. In Optical Coherence Tomography and Coherence Domain Optical Methods in Biomedicine XIV [75540T] (Progress in Biomedical Optics and Imaging - Proceedings of SPIE; Vol. 7554). https://doi.org/10.1117/12.843261