(628h) Microfluidic Embryo Well Array for Parallelized End-on Imaging and Microinjection

Many of the developmental processes that regulate embryogenesis are conserved across eukaryotes, and therefore make studying development in model organisms useful for understanding human embryonic development. The fruit fly, Drosophila melanogaster, is a well-documented model organism of developmental genetics that due to many compounding factors is more experimentally tractable than higher organisms such as mice. Yet, studies involving Drosophila are still hampered by labor intensive and time consuming protocols.  Here, we have developed a microfluidic platform that can improve throughput of two common, yet laborious tasks: live dorsal-ventral imaging and microinjection.

The microfluidic device is an array of embryo sized wells that when loaded with embryos will restrict embryo orientation to an end-on position (i.e. the dorsal-ventral plane is parallel to the device plane). Once in this position, the device can be used for directly imaging the dorsal-ventral patterning network in hundreds of embryos. Typically, dorsal-ventral imaging requires embryos to be manually oriented in an end-on position that is exceptionally time-consuming (e.g. on the order of a few embryos per minute). In comparison, this device can orient hundreds of embryos in a matter of minutes. The design of the microfluidic device also enables highly parallelized microinjection.

A second application is microinjection, which is a time-consuming process with low success rates that require many embryos to be injected to successfully create transgenic organisms. In fruit flies, this process is further hindered by the requirement of injecting embryos from the posterior. This microfluidic device arrays hundreds of embryos in an end-on position that can be used in a parallelized microinjection scheme. Our device is easy to use, because it can orient embryos through passive hydrodynamics requiring minimal manual manipulation. Furthermore, the wells robustly hold embryos in place during microinjection and negate the use of adhesives for immobilization. With this device, hundreds of embryos can be oriented and immobilized in a matter of minutes, and ready for injection. The dual functionality of this device should facilitate its use across the field of developmental biology and widen the available technology base.