Quantitative phase velocimetry measures bulk intracellular transport of cell mass during the cell cycle

Transport of mass within cells helps maintain homeostasis and is disrupted by disease and stress. Here, we develop quantitative phase velocimetry (QPV) as a label-free approach to make the invisible flow of mass within cells visible and quantifiable. We benchmark our approach against alternative image registration methods, a theoretical error model, and synthetic data. Our method tracks not just individual labeled particles or molecules, but the entire flow of bulk material through the cell. This enables us to measure diffusivity within distinct cell compartments using a single approach, which we use here for direct comparison of nuclear and cytoplasmic diffusivity. As a label-free method, QPV can be used for long-term tracking to capture dynamics through the cell cycle.

Automated summary

This study develops a quantitative phase velocimetry method to visualize and quantify the flow of mass within cells without the need for labeling. The method is benchmarked against alternative image registration methods, error models, and synthetic data, and is capable of tracking bulk material flow throughout the cell. It allows for measurement of diffusivity within different cell compartments and long-term tracking of dynamics through the cell cycle.