Optical physicist Roberto Cerbino first proposed differential dynamic microscopy (DDM) in 2008, and the technique is now being used in a great variety of applications. In The Journal of Chemical Physics, Cerbino and biophysicist Pietro Cicuta review the most recent advances in DDM.
DDM extracts multi-scale, quantitative data encoded in movie images of dynamic samples, by calculating image differentials and spatial Fourier transforms. Cerbino describes DDM as “a powerful tool” because of its simplicity and flexibility to perform quantitative analysis on image-sequences captured on any type of optical microscope. The complexity of the technique lies in the analysis, where the experiment parameters determine which steps require adaptation on a case-to-case basis.
The review highlights the application of DDM for a variety of systems in physics and biology. For physicists, DDM enables the calculation of liquid dynamics, for example, measuring the viscosity of super-cooled water. For biologists, DDM’s strength lies in its standardization of analyzing unknown forms of dynamics in soft matter and biological systems. Cerbino points to one study that analyzed the multi-scale dynamics of the complex Drosophila oocyte interior, quantifying the actin mesh dynamics and vesicle transport simultaneously, and shedding light on their interplay.
The impact and range of DMM is still being explored and Cerbino believes that the technique still has a lot of untapped potential. Currently Cerbino and colleagues are attempting to adapt the algorithm to enable DDM readings to be supplied in real-time. The paper predicts DDM applications in health-care (e.g. assessing motility of sperm in fertility clinics), but also in applications beyond the microscope, for instance in crowd monitoring and analysis of ocean waves.
Source: “Perspective: Differential dynamic microscopy extracts multi-scale activity in complex fluids and biological systems,” by Roberto Cerbino and Pietro Cicuta, The Journal of Chemical Physics (2017). The article can be accessed at https://doi.org/10.1063/1.5001027.
