title: In vivo quantification of spatially varying mechanical properties in developing tissues.
abstract: The mechanical properties of the cellular microenvironment and their spatiotemporal variations are thought to play a central role in sculpting embryonic tissues, maintaining organ architecture and controlling cell behavior, including cell differentiation. However, no direct in vivo and in situ measurement of mechanical properties within developing 3D tissues and organs has yet been performed. Here we introduce a technique that employs biocompatible, magnetically responsive ferrofluid microdroplets as local mechanical actuators and allows quantitative spatiotemporal measurements of mechanical properties in vivo. Using this technique, we show that vertebrate body elongation entails spatially varying tissue mechanics along the anteroposterior axis. Specifically, we find that the zebrafish tailbud is viscoelastic (elastic below a few seconds and fluid after just 1 min) and displays decreasing stiffness and increasing fluidity toward its posterior elongating region. This method opens new avenues to study mechanobiology in vivo, both in embryogenesis and in disease processes, including cancer.
authors.affiliation: Department of Mechanical Engineering, University of California, Santa Barbara, California, USA.|California NanoSystems Institute, University of California, Santa Barbara, California, USA.
authors.forename: Friedhelm
authors.initials: F
authors.lastname: Serwane
authors.affiliation: Department of Mechanical Engineering, University of California, Santa Barbara, California, USA.|California NanoSystems Institute, University of California, Santa Barbara, California, USA.
authors.forename: Alessandro
authors.initials: A
authors.lastname: Mongera
authors.affiliation: Department of Mechanical Engineering, University of California, Santa Barbara, California, USA.|California NanoSystems Institute, University of California, Santa Barbara, California, USA.
authors.forename: Payam
authors.initials: P
authors.lastname: Rowghanian
authors.affiliation: California NanoSystems Institute, University of California, Santa Barbara, California, USA.|Department of Physics, University of California, Santa Barbara, California, USA.
authors.forename: David A
authors.initials: DA
authors.lastname: Kealhofer
authors.affiliation: Department of Mechanical Engineering, University of California, Santa Barbara, California, USA.|California NanoSystems Institute, University of California, Santa Barbara, California, USA.
authors.forename: Adam A
authors.initials: AA
authors.lastname: Lucio
authors.affiliation: Department of Mechanical Engineering, University of California, Santa Barbara, California, USA.|California NanoSystems Institute, University of California, Santa Barbara, California, USA.
authors.forename: Zachary M
authors.initials: ZM
authors.lastname: Hockenbery
authors.affiliation: Department of Mechanical Engineering, University of California, Santa Barbara, California, USA.|California NanoSystems Institute, University of California, Santa Barbara, California, USA.|Department of Molecular, Cell and Developmental Biology, University of California, Santa Barbara, California, USA.
authors.forename: Otger
authors.initials: O
authors.lastname: Campàs
mesh_terms: D000180:Acrylic Resins / Q000737:chemistry; D000818:Animals; D001672:Biocompatible Materials / Q000737:chemistry*; D001696:Biomechanical Phenomena; D001703:Biophysics / Q000295:instrumentation / Q000379:methods*; D004625:Embryo, Nonmammalian; D004867:Equipment Design; D060526:Magnetic Fields; D018613:Microscopy, Confocal / Q000379:methods; D013623:Tail / Q000196:embryology; D014783:Viscosity; D015027:Zebrafish / Q000196:embryology*
chemical_list: D000180:Acrylic Resins; D001672:Biocompatible Materials; C016680:polyacrylamide gels