Generalized cell morphological parameters based on interferometric phase microscopy and their application to cell life cycle characterization

Pinhas Girshovitz,Natan T Shaked

doi:10.1364/boe.3.001757

Abstract

We present analysis tools which are formulated using wide-field interferometric phase microscopy measurements, and show their ability to uniquely quantify the life cycle of live cancer cells. These parameters are based directly on the optical path delay profile of the sample and do not necessitate decoupling the refractive index and the thickness in the cell interferometric phase profile, and thus can be calculated using a single-frame acquisition. To demonstrate the use of these parameters, we have constructed a wide-field interferometric phase microscopy setup and closely traced the full lifecycle of HeLa cancer cells. These initial results show the potential of the parameters to distinguish between the different phases of the cell lifecycle, as well others biological phenomena.

Highlights

Wide-field interferometric phase microscopy (IPM), known as digital holographic microscopy (DHM), provides a powerful quantitative tool for label-free biological cell investigation, while offering unique advantages over conventional bright-field microscopy techniques, which lack imaging contrast due to the cell transparency in the optical regime [1].IPM measures the quantitative phase profile that is proportional to the multiplication of the cell thickness by the difference between the refractive indices of the cell and the surrounding media
In [1,2,3], it has been shown that a constant value of the refractive index can be assumed for homogeneous cells such as enucleated red blood cells, and the quantitative phase profile is proportional to the thickness profile of the sample
The first type of methods cannot be used for most biological cells since the heterogeneity of the cell refractive index will lead to significant errors in the measurement, while the latter methods have a risk of losing cell dynamics since more than a single frame of acquisition is needed

Summary

Introduction

Wide-field interferometric phase microscopy (IPM), known as digital holographic microscopy (DHM), provides a powerful quantitative tool for label-free biological cell investigation, while offering unique advantages over conventional bright-field microscopy techniques, which lack imaging contrast due to the cell transparency in the optical regime [1].IPM measures the quantitative phase profile that is proportional to the multiplication of the cell thickness by the difference between the refractive indices of the cell and the surrounding media. Other studies have shown that it is possible to calculate the cell refractive index profile by restricting the Received 5 Apr 2012; revised 30 May 2012; accepted 3 Jun 2012; published 29 Jun 2012 1 August 2012 / Vol 3, No 8 / BIOMEDICAL OPTICS EXPRESS 1758 cells to a known thickness [8,9]. This method, might influence the cell normal behavior

Methods

Results

Conclusion