Quantitative Phase Imaging for Label-Free Analysis of Cancer Cells—Focus on Digital Holographic Microscopy

Abstract

Abstract:To understand complex biological processes, scientists must gain insight into the function of individual living cells. In contrast to the imaging of fixed cells, where a single snapshot of the cell's life is retrieved, live-cell imaging allows investigation of the dynamic processes underlying the function and morphology of cells. Label-free imaging of living cells is advantageous since it is used without fluorescent probes and maintains an appropriate environment for cellular behavior, otherwise leading to phototoxicity and photo bleaching. Quantitative phase imaging (QPI) is an ideal method for studying live cell dynamics by providing data from noninvasive monitoring over arbitrary time scales. The effect of drugs on migration, proliferation, and apoptosis of cancer cells are emerging fields suitable for QPI analysis. In this review, we provide a current insight into QPI applied to cancer research.

Evaluation of holographic imaging cytometer holomonitor M4® motility applications

“…Recently, several approaches for quantitative phase imaging (QPI) have been developed for live-imaging of cancer cells in culture (8)(9)(10)(11)(12)(13)(14)(15)(16)(17). As a label-free imaging technology that is non-cytotoxic even with prolonged exposure, QPI is a noninvasive method for single cell analysis of adherent cell behavior.…”

“…(8)). (8,24)). Collectively, these and other reports have fully established QPI platforms as quantitative time-lapse cytometers with single cell resolution.…”

“…QPI has been used as the basis for reporting on cell proliferation, morphology, and motility (reviewed in Ref. (8)). More recent reports have used machine learning based analyses of features derived from QPI images to distinguish metastatic potential, drug-response, program activation, and modes of cellular migration (17)(18)(19)(20)(21)(22).…”

“…Motility was among the first cellular behaviors analyzed by QPI, and many groups have reported the measurement of cancer cell motility using QPI platforms (reviewed in Refs. (8,24)). However, as commercial systems with proprietary application-specific data analysis software packages (or referred to here as modules) are distributed to a wider range of laboratories, it is important to demonstrate not only that cellular behavior can be quantified using these systems, but also to evaluate the accuracy and reproducibility of these approaches, as well as their correlation to known standards.…”

Moving into a new dimension: Tracking migrating cells with digital holographic cytometry in 3D

“…Indeed, this opens up for almost unlimited possibilities to perform cell morphology analysis using the QPI methodology, since each image is very rich in cellular information. As discussed in a review by El-Schich et al, automated analysis and machine learning is one approach to handle the large amount of morphological data that can now be generated when analyzing cells with QPI (8). Only the computer resources and the training speed will set the limitations.…”