Probing multi-scale dynamics in complex fluids and biological systems with differential dynamic microscopy
Roberto Cerbino
Wednesday 8 Mars 2023 32-42 room 101
Abstract
Complex and biological fluids are often composed of a variety of structures that can exhibit a wide range of dynamic phenomena at different spatial and temporal scales. From the diffusion of individual particles to the collective motion of large ensembles, being able to quantify the dynamics is crucial to understanding the properties and behavior of such systems. To this aim, researchers have developed a variety of experimental techniques, including microscopy, rheology, spectroscopy, and scattering, each with its own advantages and limitations. Among these techniques, differential dynamic microscopy (DDM) has emerged as a flexible and powerful tool to perform a multiscale characterization of the dynamics by analyzing videos of the sample acquired in direct space during microscopy experiments. These videos are analyzed to extract reciprocal space information about the system dynamics (similar to Dynamic Light Scattering or X-Ray Photon Correlation Spectroscopy), and one single DDM experiment can probe simultaneously hundreds to thousands of different wave-vectors. In this talk, we will focus on DDM and its applications in soft matter and biological fluids. We will explore the fundamental principles behind DDM, discuss the experimental setup required for DDM measurements, and highlight the analysis methods used to extract quantitative information from the data. We will also showcase examples of DDM applications, including the study of the dynamics of nanoparticles and the characterization of non-equilibrium behavior, also in active systems.
