Cellular metabolism is a complex, integrated process that is supported by key organelles, such as lipid droplets and mitochondria, which engage in numerous energetic and signaling mechanisms.

A better understanding of the dynamics and interactions of such organelles could advance research in aging, cancer, degenerative diseases or obesity.

Non-invasive live cell imaging overcomes phototoxicity problem while imaging cellular metabolism processes

A major problem with current imaging techniques is phototoxicity that leads to the observation of perturbed dynamics. Consequently, the mitigation of phototoxicity leads to poor time resolution of time lapse approaches. This is particularly true for small organelles like mitochondria or lipid droplets that are extremely sensitive to photo-induced oxidation. Last but not least, the use of chemical or genetically-encoded fluorescent markers perturbs the targeted biological processes.

However, the 3D Cell Explorer overcomes this problematic as it injects in the sample ~100 times less energy (~0.02 nW/µm2) than light sheet microscopes (~1nW/µm2) that are the reference in the matter. With a resolution below 200 nm, it enables high resolution and high-frequency imaging even with sensitive material, giving access to organelle dynamics that were previously out of reach.

Novel movies showing lipid droplets and mitochondria fine dynamics live and at high resolution

Thanks to the 3D Cell Explorer’s live imaging capabilities, highlights of lipid droplets and mitochondria fine dynamics that were previously out of reach are clearly visible now.

The movies presented hereafter were taken at a frequency of one image per five seconds. This acquisition frequency can be reached over long periods of time thanks to the absence of phototoxicity with Nanolive’s imaging technique which allows to obtain label-free images at high spatial and temporal resolution (the 3D Cell Explorer has a unique implementation of holotomographic microscopy).

The two movies here below, obtained from the same time-lapse, show the close and mysterious relation between lipid droplets and mitochondria1. On top of sharing common dynamics and trajectories, mitochondria are reaching out towards lipid droplets, making clear contacts and moving away. LD-mitochondria contacts are seen here like never before, which opens doors towards a better understanding of LD-mitochondria interdependency in unperturbed or perturbed conditions.