Three-dimensional label-free imaging and quantification of lipid droplets in live hepatocytes

TL;DR

This paper introduces a label-free 3-D imaging technique using quantitative phase imaging to analyze lipid droplets in live hepatocytes, enabling detailed structural, biochemical, and dynamic studies without exogenous labels.

Contribution

It presents a novel optical method for 3-D quantitative imaging of lipid droplets in live cells, capturing their structure, biochemistry, and dynamics in real-time.

Findings

Quantitative 3-D distribution and biochemical parameters of LDs were measured.

LDs' response to oleic acid treatment was quantitatively analyzed.

Fast 4-D tracking revealed intracellular transport dynamics of LDs.

Abstract

Lipid droplets (LDs) are subcellular organelles with important roles in lipid storage and metabolism and involved in various diseases including cancer, obesity, and diabetes. Conventional methods, however, have limited ability to provide quantitative information on individual LDs and have limited capability for three-dimensional (3-D) imaging of LDs in live cells especially for fast acquisition of 3-D dynamics. Here, we present an optical method based on 3-D quantitative phase imaging to measure the 3-D structural distribution and biochemical parameters (concentration and dry mass) of individual LDs in live cells without using exogenous labelling agents. The biochemical change of LDs under oleic acid treatment was quantitatively investigated, and 4-D tracking of the fast dynamics of LDs revealed the intracellular transport of LDs in live cells.