Freeze-Dried Mouse Sperm Sent by Postcard Produces Baby Mice

Rather than relying on samples that need to be shipped in glass vials and on ice, researchers have developed a new method that allows mouse sperm to be sent easily at room temperature using standard mail delivery.

Written byAmanda Heidt

| 4 min read

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One hand holds a white envelope with a blue and red striped border, while a second hand places a clear sheet of plastic inside with small squares of paper on it

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ABOVE: By freeze-drying mouse sperm on weighing paper and sandwiching the paper between protective plastic sheets, researchers were able to successfully mail the samples between labs in Japan.
DAIYU ITO, UNIVERSITY OF YAMANASHI

With mouse models undergirding so much scientific research, scientists have a vested interest in developing techniques to safely store and transport sperm samples between labs. Currently, most methods rely on shipping sperm in glass vials packed on dry ice, but glass is both heavy—raising the cost of shipping—and prone to breakage. In addition, any delays in shipping can result in thawed and unusable samples. In search of a better option, a team of scientists in Japan recently sent mouse sperm that was freeze-dried onto simple weighing paper and stored between two plastic sheets by postcard roughly 200 kilometers, from Kyoto to Yamanashi, where the rehydrated sperm fertilized eggs and produced healthy baby mice.

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Meet the Author

Amanda Heidt
Amanda first began dabbling in scicom as a master’s student studying marine science at Moss Landing Marine Labs, where she edited the student blog and interned at a local NPR station. She enjoyed that process of demystifying science so much that after receiving her degree in 2019, she went straight into a second master’s program in science communication at the University of California, Santa Cruz. Formerly an intern at The Scientist, Amanda joined the team as a staff reporter and editor in 2021 and oversaw the publication’s internship program, assigned and edited the Foundations, Scientist to Watch, and Short Lit columns, and contributed original reporting across the publication. Amanda’s stories often focus on issues of equity and representation in academia, and she brings this same commitment to DEI to the Science Writers Association of the Rocky Mountains and to the board of the National Association of Science Writers, which she has served on since 2022. She is currently based in the outdoor playground that is Moab, Utah. Read more of her work at www.amandaheidt.com.
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