Cryobiopechat

3d-printed fabrics can now be stored in the cold for several months

Tatiana Matveeva, "Scientific Russia"

American scientists have combined 3D bioprinting with cryopreservation to create artificial tissues that can be stored in a freezer at -196 °C and defrosted for several minutes to be used immediately, EurekAlert! reports. A description of the process is presented in the journal Matter (Ravanbakhsh et al., Freeform cell-laden cryobioprinting for shelf-ready tissue fabrication and storage).

In the case of conventional bioprinting, special ink is squeezed out of the nozzle, "printing" layer by layer the fabric of the desired shape. Cryobrinting works the same way, except that printing is performed directly on a cold plate, maintained at temperatures up to -20 °C. The finished fabric is immediately transferred to cryogenic conditions for long-term storage.

Printing at low temperatures has a significant advantage: it can be used to create more complex shapes. "The biochernil thread freezes within milliseconds after it touches the cold plate, so it does not have time to lose its original shape," the authors note. "Then you can lay out layers on top of each other, eventually creating a three–dimensional structure that can support its own weight."

Cryobrinting also allows the use of more types of biochernils. In traditional methods, ink must be viscous to maintain its shape, but at a lower temperature, most liquids naturally acquire such a texture.

To survive at low temperatures, a cryopreservant must be added to the cells, which prevents osmotic shock and prevents the formation of ice crystals that can damage cell membranes. The team managed to find a combination of cryopreservants that provide the highest cell viability. 

The printed fabrics were frozen for three months before being "brought back to life." For comparison, the shelf life of conventional biological tissues can range from several hours to several days.

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