Mechanical interferometry of nanoscale motion and local mechanical properties of living zebrafish embryos.

We present an interferometric imaging technique that permits local measurement of mechanical properties and nanomechanical motion in small living animals. Measurements of nanomechanical properties and spatially resolved pulsations of <60 nm were recorded for the developing eye of a living zebrafish (Danio rerio) embryo, an important model organism. We also used magnetic microreflectors to conduct contact nanomechanical indentation measurements of the stiffness of the embryonic eye.