Although 3D printing of tissues and organs has great potential in the medical field , the materials used in printing usually have a rather short shelf life. Recently, American scientists have created a new bio-ink that ensures the preservation of printed tissues in a frozen state for several months.
Modern technologies allow the use of biomaterials for implantation in a period from several hours to several days from the date of creation. This indicator can be influenced by a variety of factors, but the main ones are the properties of the printed material itself. Such restrictions can be especially relevant in situations where tissue is printed far from the patient’s location. This also means that replacement organs cannot be printed out in advance and then kept ready for immediate implantation in an emergency.
A group of researchers from Harvard University and the Women’s Hospital undertook to solve this problem. They have developed a new bio-ink that allows them to print tissue that not only can be stored frozen for months, but can be prepared for implantation in minutes.
Like other materials for 3D printing organs, the new composition consists of a gelatinous matrix that acts as a scaffold, which is filled with living cells. Its special ingredients are cryopreservatives that prevent osmotic shock and limit the formation of ice crystals that damage cell membranes.
New bio-ink includes the pharmaceutical drug dimethyl sulfoxide (DMSO) and maltose sugar. They are applied directly from the printer nozzle onto a cold plate with a temperature of -20 C and instantly freeze. In their decision, American scientists overcame the limitations of existing materials, which are often too soft and fluid, which makes it difficult to obtain a given shape.
“The bio-ink filament freezes within milliseconds of contact with the cold plate, so it doesn’t have time to lose its original shape,” says Professor Shrike Zhang. “You can then build layers on top of each other, ultimately creating a separately strong three-dimensional structure that can support its own weight.”
In laboratory tests, tissue printed with bio-ink was stored at -196 ºC for at least three months. When it was subsequently placed in a warm liquid environment, its constituent cells remained viable and continued to differentiate as in their natural environment.