Label-free 3D visualization and quantification of endogenous and exogenous intracellular particles in single cells by phase-contrast holographic flow tomography

Detection and quantification of intracellular structures is fundamental in biomedical sciences. New emerging inspection tools based on holographic microscopy and quantitative phase imaging can give answers to such critical demands. Holographic tomography (HT) systems are the best candidates for this challenge. Recently, HT has been demonstrated working in flow-cytometry (FC) modality. Results show that the novel HTFC tool is capable to furnish 3D visualization and quantifications of the different intracellular particles. In particular, here we report that exogenous nanographene oxide particles as well as endogenous lipid droplets can be detected, measured, and visualized in each flowing cell by label-free HTFC. This method opens the way for accurate and high-throughput measurements at the 3D single-cell level for different applications such as diagnosis of diseases, development of drug delivery applications, and examination of cell functionalities. Experiments and processing methods will be described, and several examples will be discussed.