Detecting active Lévy particles using differential dynamic microscopy

Area of Science:

• Biophysics
• Cell Biology
• Statistical Mechanics

Background:

• Detecting Lévy flights in cellular systems is experimentally challenging due to the need for broad spatiotemporal data.
• Differential dynamic microscopy (DDM) offers a powerful approach for analyzing motion across various scales.

Purpose of the Study:

• To extend differential dynamic microscopy (DDM) for detecting active Lévy particles with algebraic tail run-time distributions.
• To validate the enhanced DDM protocol using synthetic data and experimental biological samples.

Main Methods:

• Extension of differential dynamic microscopy (DDM) to analyze self-propelled particles exhibiting Lévy flight characteristics.
• Validation using simulated imaging data to determine necessary length scales for detection.
• Application of the DDM protocol to experimental data from E. coli and E. gracilis.

Main Results:

• Reliable detection of active Lévy particles requires observing length scales significantly larger than their persistence length.
• Experimental data analysis revealed that E. coli does not display Lévy walk signatures.
• E. gracilis movement patterns are better characterized as active Lévy particles.

Conclusions:

• The enhanced DDM method provides a robust framework for identifying active Lévy particles in biological systems.
• Differential dynamic microscopy is a versatile tool for uncovering complex cellular motility patterns.
• Distinguishing between different motility regimes, such as normal diffusion versus Lévy flights, is crucial for understanding cell behavior.