Live-cell mass profiling: an emerging approach in quantitative biophysics

Abstract

Cell mass, volume and growth rate are tightly controlled biophysical parameters in cellular development and homeostasis, and pathological cell growth defines cancer in metazoans. The first measurements of cell mass were made in the 1950s, but only recently have advances in computer science and microfabrication spurred the rapid development of precision mass-quantifying approaches. Here we discuss available techniques for quantifying the mass of single live cells with an emphasis on relative features, capabilities and drawbacks for different applications.

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

“…Typically, it consists of one or several reconstruction stages using Fourier Transforms and a focal selection stage, followed by one or more post-processing calculations where modular phase recordings are unwrapped and edge effects removed [4]. The risk of introducing image artefacts in the unwrapping stage is reduced if the sample phase shift is less than one wavelength, or it can be avoided completely by imaging at several wavelengths, thus also allowing for imaging thicker specimens [73,77,78]. All image reconstruction and manipulation stages can be performed after capture, as the complete three-dimensional information of the sample is stored in the interferometric recording.…”

Time-stretch microscopy on a DVD for high-throughput imaging cell-based assay

“…cell size, mass, density and other cellular mechanical properties. These intrinsic phenotypes are known to be closely correlated with the malignancy transformation and are thus effective biomarkers of cancer screening as well as drug development [23][24][25]. Especially regarding the drug development process, largeformat spinning disc also favors highly-multiplexed imaging assay and can potentially be used for efficient (cancer) drug screening against hundreds to tens of thousands compounds.…”

High-Resolution 3-D Refractive Index Tomography and 2-D Synthetic Aperture Imaging of Live Phytoplankton

“…The error term means a standard deviation of the parameter. The dry masses of non-aqueous biomolecules [35][36][37] in individual phytoplankton are determined from the measured high-resolution 2-D quantitative phase images using the synthetic aperture algorithm. The integration of optical path length values over an area of individual phytoplankton is linearly proportional to the total dry mass in the phytoplankton via a proportional constant called RI increment [37], because the RI of biomaterials such as cells and tissues is linearly proportional to the concentration of nonaqueous biomolecules.…”