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Journal of Biomedical Optics • Open Access

Reconstruction of explicit structural properties at the nanoscale via spectroscopic microscopy
Author(s): Lusik Cherkezyan; Di Zhang; Hariharan Subramanian; Allen Taflove; Vadim Backman

Paper Abstract

The spectrum registered by a reflected-light bright-field spectroscopic microscope (SM) can quantify the microscopically indiscernible, deeply subdiffractional length scales within samples such as biological cells and tissues. Nevertheless, quantification of biological specimens via any optical measures most often reveals ambiguous information about the specific structural properties within the studied samples. Thus, optical quantification remains nonintuitive to users from the diverse fields of technique application. In this work, we demonstrate that the SM signal can be analyzed to reconstruct explicit physical measures of internal structure within label-free, weakly scattering samples: characteristic length scale and the amplitude of spatial refractive-index (RI) fluctuations. We present and validate the reconstruction algorithm via finite-difference time-domain solutions of Maxwell’s equations on an example of exponential spatial correlation of RI. We apply the validated algorithm to experimentally measure structural properties within isolated cells from two genetic variants of HT29 colon cancer cell line as well as within a prostate tissue biopsy section. The presented methodology can lead to the development of novel biophotonics techniques that create two-dimensional maps of explicit structural properties within biomaterials: the characteristic size of macromolecular complexes and the variance of local mass density.

Paper Details

Date Published: 17 February 2016
PDF: 11 pages
J. Biomed. Opt. 21(2) 025007 doi: 10.1117/1.JBO.21.2.025007
Published in: Journal of Biomedical Optics Volume 21, Issue 2
Show Author Affiliations
Lusik Cherkezyan, Northwestern Univ. (United States)
Di Zhang, Northwestern Univ. (United States)
Hariharan Subramanian, Northwestern Univ. (United States)
Allen Taflove, Northwestern Univ. (United States)
Vadim Backman, Northwestern Univ. (United States)

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