Quantitative phase microscopy for non-invasive live cell population monitoring

Abstract

We present here a label-free development based on preexisting Quantitative Phase Imaging (QPI) that allows non-invasive live monitoring of both individual cells and cell populations. Growth, death, effect of toxic compounds are quantified under visible light with a standard inverted microscope. We show that considering the global biomass of a cell population is a more robust and accurate method to assess its growth parameters in comparison to compiling individually segmented cells. This is especially true for confluent conditions. This method expands the use of light microscopy in answering biological questions concerning live cell populations even at high density. In contrast to labeling or lysis of cells this method does not alter the cells and could be useful in high-throughput screening and toxicity studies.

Multiparametric quantitative phase imaging for real-time, single cell, drug screening in breast cancer

“…Quantitative phase imaging (QPI) is a real-time, label-free technique for determining the growth of individual cells by measuring the phase shift of light as it passes through a transparent sample such as a cell 23 , 26 . This quantity is directly proportional to cell mass, which increases due to cell growth, such as during progression through the cell cycle 27 , 28 .…”

Mitotic Index Determination on Live Cells From Label-Free Acquired Quantitative Phase Images Using a Supervised Autoencoder

“…We investigated whether high resolution quadri-wave lateral shearing interferometry, that allows quantitative linear retardance and birefringence measurements on biological samples could allow non-invasive monitoring of the cell cycle in populations. The QPI strategy, presented in [16], [28], only requires short bursts of low intensity white light which appears to have a negligible effect on cell physiology. The optical phase difference measured when photons exit a biological sample is a direct reflection of the dry mass present in the sample being analyzed.…”

“…It has been shown for example that the mass increase associated with cellular cell cycle progression (2N toward 4N chromosomes) can be accurately determined [1]. In addition, the characteristic cell rounding associated with the late G2 phase is also easily detected by QPI [28]. Biologists partners [17] have investigated how reliable this approach would be to monitor a live cell population under the microscope.…”

Functional imaging with dynamic quantitative oblique back-illumination microscopy

“…Quantitative phase imaging (QPI) has become a mainstay label-free technology for monitoring live cells and their growth without the need for exogenous labels or stains, which can alter their behavior and function. [1][2][3] This technique reveals information about a sample's optical path length, yielding access to cellular structures below a nanometer and a sample's refractive index (RI) distribution, which is linearly proportional to the cellular dry mass. 4 Additionally, dynamic and longitudinal studies of cells (and other thin, live organisms) are possible with this method, which provides insight into cell migration, proliferation, mass transport, and other metabolic and functional processes.…”