A new technique for culturing printed tissues for transplantation

Researchers at the Technion have developed an innovative technique to grow transplanted tissue
by printing it into a microgel bath as a support material.
The study, published in Advanced Science, was led by Professor Shulamit Levenberg and her PhD student Majd Machour in the School of Biomedical Engineering, and Professor Havazelet biano-peled and PhD student Noy Hen in the Wolfson School of Chemical Engineering, and was led by the Norman Seiden Multidisciplinary Graduate Program
in Nanoscience and Nanotechnology.

Tissue printing is an innovative way
to create transplanted tissue.
In this technique, also known as bioprinting, living cells are embedded in bioink, printed layer by layer
.
The printed tissue then grows for days or weeks until it is ready to be printed
.

According to Professor Levenberg, "Many research groups around the world are working to improve tissue printing, but most of them are focused on the printing phase and the initial product – the printed tissue
.
However, the stage of tissue growth – the period between printing and transplantation to the target organ – is equally important
.
It is a complex period in which printed cells divide, migrate, secrete an extracellular matrix, and connect with each other to form tissues
.
One of the problems is that in this complex process, tissues tend to twist and contract
in uncontrolled ways.
”

Therefore, Technion's researchers focused on preventing the printed tissue from shrinking
unevenly in the weeks after printing.
The solution is found by altering the medium in which the tissue is printed and
grown.
The new concept of "print-grow" is based on an original medium developed by the researchers – an innovative microgel that is used as a support material in the process, a substance composed mainly of carrageenan that is produced from red algae
.
In fact, the new support bath preserves the size of the printed tissue, preventing it from shrinking and losing shape
.
This process enables the reliable and controlled production of functional tissue
of the required size and shape.
Because the material is transparent, scientists can monitor tissue development
through imaging.

Technion researchers hope this new method will lead to the development of
new bioprinting technologies.
The research was funded
by ERC (European Research Council) from the European Union.

About a year ago, Professor Levenberg published another breakthrough
in bioprinting in the field of advanced materials.
In this study, she was able to create printed tissue flaps based on collagen and living cells that contain the large and small blood vessels that supply blood to the tissue and make it possible
to connect with arteries after transplantation.
This allows blood to flow into the engineered tissue immediately after transplantation, accelerating and improving the fusion
of tissues in the body.