Quantifying Particle Dynamics in 3D with Light Field Microscopy

Optical microscopy is often used to quantify the dynamics of colloidal particles or other objects and applied to disciplines ranging from materials science to biophysics. However, most microscopy methods can only quantify dynamics in two dimensions (2D). Here we show how images collected with light field microscopy (LFM) can be easily analyzed with single particle tracking and differential dynamic microscopy. We have adapted these image analysis techniques, often used to measure dynamics in 2D, to quantify 3D dynamics when applied to data from a LFM. Existing methods to extract 3D information from LFM are often computationally expensive and complex. We bypass the need to computationally reconstruct 3D volumes, as is commonly done with LFM, by applying either differential dynamic microscopy methods or single particle tracking on the raw images collected with our LFM. We showcase how LFM, a relatively inexpensive form of microscopy, can be used with our image analysis methods to quantify the 3D dynamics of diffusing and sedimenting colloidal particles.