The MVE BL-7 Straw Retriever is a specialized tool designed to safely and efficiently extract frozen French straws from the bottom of an MVE BL-7 nitrogen vapor shipping dewar—without tipping, inverting, or disturbing the vessel’s contents. Traditionally, retrieving French straws required turning the dewar upside down, posing risks of sample warming or loss of nitrogen containment. The Straw Retriever eliminates these hazards by enabling upright recovery of straws while maintaining cryogenic integrity.

Although it was designed specifically for the MVE BL-7, the straw retriever is compatible with any dewar that has a neck opening of 1.97 inches (50 mm).

The retriever can be pre-filled with a small volume of liquid nitrogen, helping maintain the straws at cryogenic temperatures throughout the retrieval process. A string or wire must be securely attached to the loop at the top of the device before it is lowered into the dewar. The triangular openings along the sides of the device serve a dual purpose: they prevent implosion when lowered into the dewar, and prevents overfilling liquid nitrogen when transferring out of the dewar. When paired with the Micro Cajun Ejector, the system forms a complete, field-ready solution for safe, repeatable access to cryopreserved germplasm—ideal for remote, mobile, or resource-limited environments.

Designed by Brittany Ratliff and colleagues at the Aquatic Germplasm and Genetic Resources Center (AGGRC). This work was funded by the National Institute of Health (NIH).

Please visit AGGRC.com to learn more about our work.

All Fusion 360 files can be found on our GitHub through the following link:

https://github.com/aggrc/MVE-BL-7-Straw-Retriever