Acoustic Tweezers for Microscopy of Living Organisms.

Studying zebrafish embryos' growth through imaging them in their natural growth environment may reveal what has not been possible through the current imaging technique which uses mechanically-confining and nutrient-limiting gel, like agarose. This paper presents, for the first time, the imaging of live zebrafish embryos in their natural environment over 20 hours through acoustic tweezers capable of contactless trapping and precise manipulation via trapping without standing waves. The tweezers is shown to trap and hold a zebrafish embryo in its growth medium from 17 hours post fertilization (hpf) to 37 hpf under a Light-Sheet microscope for imaging. The continuous trapping and imaging reveal organ development, such as the tail, eyes, ears, and pigmentation. The method is safe, as evidenced by natural development, heartbeats, and tail movement.