New bio ink may enable 3D printing organs to achieve frozen storage

2023-12-25

Although 3D bioprinting of tissues and organs does have great prospects in the medical field, the shelf life of printed materials is usually quite short. However, an experimental new bio ink can allow bioprinted tissues to be stored in a frozen state for several months. According to factors such as the printing materials used, 3D bioprinted tissues must currently be implanted within a few hours to days after creation.

In cases where the organization is printed in one place but needs to be used on patients in another place, this limitation may be particularly problematic. This also means that things like replacement organs cannot be printed out in advance and immediately implanted when needed.

To address these issues, scientists from Brigham Women's Hospital affiliated with Harvard University have created this new freezeable bio ink. The tissue made from it can not only be frozen for several months but also thawed and ready for use within a few minutes.

Like other more traditional bio inks, it is composed of a scaffold like gelatin matrix embedded in living cells. However, its special component is a refrigerant, which can prevent osmotic shock and limit the formation of ice crystals that damage cell membranes. Assistant Professor Yu Shrike Zhang, the chief scientist of this study, introduced that these drugs include dimethyl sulfoxide (DMSO) and maltose.

Biological ink deposits directly from the nozzle of the biological printer onto a -20 º C cold plate and freezes instantly. This process overcomes the limitations of existing bio inks, as some bio inks may be too soft and fluid to form the desired items.

Zhang said, "The bio ink filament freezes within a few milliseconds of reaching the cold plate, so it doesn't have time to lose its original shape. Then you can build layers on top of each other and ultimately create an independent three-dimensional structure that can withstand its own weight."

In laboratory testing, tissues printed with bio ink were stored at -196 º C for at least three months. When it is subsequently thawed in a warm liquid medium, the cells inside are still viable and continue to differentiate as they usually do.

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