Custom 3D-Printed Molds for Zebrafish Imaging and Cardiac Development

Embryo mounting is one of the technical challenges researchers encounter when undertaking an imaging project. Embryos need to be oriented in a reproducible manner such that the tissue of interest is accessible to a microscope objective for the entire imaging period. To overcome this challenge, researchers can embed embryos in viscous media or create specialized dishes and casts to hold embryos in a desired orientation during imaging. Here, we describe a method for using an inexpensive stereolithographic (SLA) 3D-printer to manufacture reusable molds that create agarose wells in which embryos can be mounted for imaging. These agarose wells provide a reliable means for orienting multiple embryos for imaging. This method includes a design framework that can be easily customized for a variety of tissues, organisms, and imaging challenges. Using this method, we have created molds for imaging cardiac development in zebrafish for both upright and inverted microscopes. By utilizing materials and equipment that are accessible, this method allows researchers to easily create molds specific to their mounting needs.