Fabio Giavazzi, Probing multi-scale dynamics of complex fluids and biological systems with differential dynamic microscopy

Department of Medical Biotechnology and Translational Medicine, University of Milan

Imaging is, in its many forms, a cornerstone of modern science. From astronomy to cell biology, from medicine to material science, obtaining space-resolved maps – images – of the system under study is considered a key step in the process of “understanding” it. Nevertheless, and despite the common belief that “a picture is worth a thousand words”, releasing the full informative potential of an image or an image sequence can be a challenging task, in particular when the objects of interest are small, or the system is crowded, or the environment is complex, or the detection chain is noisy, or all the above together.In this seminar, I will introduce the basics of differential dynamic microscopy – an image analysis scheme based on the study of time correlations in the spatial Fourier domain – enabling the extraction of statistically robust information on the dynamics of a sample from a sequence of images, even in conditions where a direct-space approach, based for example on image segmentation or particle tracking, would be difficult or impossible.I will discuss the potential and limitations of the method, presenting selected applications in a broad spectrum of soft and bio-soft matter problems, ranging from thermal fluctuations in liquid crystals and critical fluids to collective migration in cell monolayers,  from microrheology of complex fluids to bubble rearrangement dynamics in a coarsening foam.