Brain tissue kept alive for weeks on an artificial membrane

Researchers at the RIKEN Center for Biosystems Dynamics Research in Japan have developed a new system for keeping tissue viable for long-term study once transferred from an animal to a culture medium. The new system uses a microfluidic device that can keep tissue from both drying out and from drowning in fluid.

A proof-of-concept experiment showed that tissue explanted from the mouse brain remained viable after almost one month in culture, much longer than is possible with other microfluidic culturing methods, and also much simpler.

Experimenting on tissues in culture can facilitate drug discovery because researchers can systematically manipulate the tissue and test different drugs or drug combinations. However, when studying a whole system in which many cells must interact with each other, it has proven difficult to keep the tissue "alive" for more than a few days. Tissue dries out quickly and dies unless it is put into a wet culture medium with appropriate nutrients. On the other hand, immersing complex tissue in fluid can damage the tissue because it does not allow the normal transfer of gases between them.

To solve this problem, the RIKEN scientists developed a microfluidic device using polydimethylsiloxane (PDMS), the material often used as a defoamer in over-the-counter drugs. The device has a semi-permeable channel surrounded by an artificial membrane and solid PDMS walls.

Rather than constantly being immersed in fluid, the tissue benefited from having the culture medium circulate within the microchannel and pass through the permeable membrane, which allowed proper gas exchange.