Edera, Paolo Bergamini, Davide Trappe, Véronique Giavazzi, Fabio Cerbino, Roberto 2017-12-29 Particle-tracking microrheology (PT-μr) exploits the thermal motion of embedded particles to probe the local mechanical properties of soft materials. Despite its appealing conceptual simplicity, PT-μr requires calibration procedures and operating assumptions that constitute a practical barrier to its wider application. Here we demonstrate differential dynamic microscopy microrheology (DDM-μr), a tracking-free approach based on the multiscale, temporal correlation study of the image intensity fluctuations that are observed in microscopy experiments as a consequence of the translational and rotational motion of the tracers. We show that the mechanical moduli of an arbitrary sample are determined correctly over a wide frequency range provided that the standard DDM analysis is reinforced with an iterative, self-consistent procedure that fully exploits the multiscale information made available by DDM. Our approach to DDM-μr does not require any prior calibration, is in agreement with both traditional rheology and diffusing wave spectroscopy microrheology, and works in conditions where PT-μr fails, providing thus an operationally simple, calibration-free probe of soft materials. application/pdf https://folia.unifr.ch/global/documents/306266 https://folia.unifr.ch/documents/306266/files/tra_ddm.pdf eng info:eu-repo/semantics/altIdentifier/doi/10.1103/PhysRevMaterials.1.073804 info:eu-repo/semantics/openAccess License undefined Physical Review Materials. - 2017, vol. 1, no. 7, p. 073804 info:eu-repo/classification/udc/53 Differential dynamic microscopy microrheology of soft materials: A tracking-free determination of the frequency-dependent loss and storage moduli http://purl.org/coar/resource_type/c_6501