CAJUN EJECTOR V1.0: 3D PRINTED STRAW FREEZING DEVICE
BILL CHILDRESS - RESEARCH ASSOCIATE
Cajun Ejector v1.0 (Fig. 1) is a type of Positional Cooling Platform Devices (PCPD). It is a 3-D printed standardizable freezing device that can be used with nitrogen vapor shipping dewars for on-site sperm cryopreservation for aquatic species and be distributed as open-source hardware. The Cajun Ejector comprised eight 3-D printed components and a metal spring. There were nine height slots to provide a range of cooling rates by control of vertical positioning within a liquid nitrogen shipping dewar. The Cajun Ejector could hold 22 French straws (0.25-mL or 0.5-mL) and a quick-release ring design could eject straws directly into a canister inside a dewar by pressing a button after freezing. The final prototypes produced cooling rates of 1 to 64 °C/min for 0.25-mL straws, and 3 to 37 °C/min for 0.5-mL straws. These cooling rates would cover needs for sperm cryopreservation of most animal taxa. The material cost of a single unit is about $4. The Cajun Ejector can be used with a shipping dewar in laboratories or for remote field work to cryopreserve sperm and assist short-term frozen storage and transportation.