Measurement of cortical elasticity in Drosophila melanogaster embryos using ferrofluids

Significance A physically realistic understanding of any morphogenetic process requires the knowledge of material properties of the tissue, almost all of which we currently lack. This paper introduces a technique that allows measuring physical properties of the interior constituents of a fruit fly embryo. To interpret our measurements, we developed a computational framework that allowed us to deduce underlying material properties of embryonic tissues from the measured data. Using our protocol we have determined a number of key physical properties of embryonic tissue (e.g., cytoplasmic viscosity and the timescale of elastic stress relaxation). Finally, we used pharmacological perturbations to examine which cellular structures are responsible for the observed elastic response.