The University of Tokyo and RIKEN develop method to instantly freeze cell clusters under high pressure

A research group consisting of Professor Yasuyuki Sakai, Associate Professor Masaki Nishikawa, Assistant Professor Takeshi Katsuda, and Graduate Student Fang Song of the Graduate School of Engineering at the University of Tokyo, along with Senior Technical Scientist Kiminori Toyooka and Technical Scientist Mayuko Sato of the Center for Sustainable Resource Science, RIKEN, has succeeded in cryopreserving monolayer cultured cells and cell aggregates (spheroids), which had been considered difficult using conventional freezing methods such as immersion in liquid nitrogen, by freezing cells and tissue instantly in just a few milliseconds under pressure approximately 2,000 times greater than atmospheric pressure. Cells and tissues after thawing showed very high viability and cellular activity, indicating the effectiveness of the high-pressure instant-freezing method. The findings were published in PNAS Nexus.

In this study, the high-pressure freezing device Leica EM ICE, which had previously been used to prepare samples for electron microscopy, was applied to the preservation of living cells for the first time. The group succeeded in cryopreserving monolayer cultured cells and cell aggregates, both considered difficult to cryopreserve with conventional freezing methods, and in growing them after thawing at high survival rates.

Compared to previous studies, the novelty lies in the very high survival rate after thawing, the possibility of stable culture afterwards, and the fact that cryoprotectants such as DMSO, which are considered highly toxic, do not need to be used.

These findings are expected to be useful in basic research fields such as regenerative medicine, various bioindustries, and bioengineering, for example, through the preservation of small cell structures like organoids (miniature models of body tissues and organs).

Journal Information
Publication: PNAS Nexus
Title: A proof-of-concept study on high-pressure freezing for cryopreservation
DOI: 10.1093/pnasnexus/pgag065