New method for 3D-printing organs

Materials World magazine
1 Jul 2019

Researchers are developing a new method to 3D print organs using photosensitive hydrogels and light sheet illumination. Idha Valeur reports.

A new method of 3D printing organs has received three years of funding for development by a consortium of researchers. The project, Bioprinting by light sheet lithography: engineering complex tissues with high resolution at high speed, or BRIGHTER, will start this July.

Printing tissue has become more and more common, but complex organs are rarely viable as the process itself causes cells to die. There has been some research into using bio-inks, which have living cells incorporated into them, but it has not yet resulted in a living, functional organ. The objective of the BRIGHTER project is to print organs using the patient’s own cells rather than rely on donated organs or animal experiments.

One of the difficulties with existing bio-printing is the method. By printing from the bottom-up, adding layer upon layer, the cells in the ink are unable to survive, as the method takes too long. Other disadvantages include too low a resolution at approximately 300 micrometres, which is not high enough to create delicate structures such as natural tissue. This is where the consortium’s new process comes in.

Coordinated by the Institute for Bioengineering of Catalonia, Spain, Group Leader of biomimetic systems for cell engineering, Elena Martínez Fraiz, the new process relies on photosensitive hydrogels blended with living cells and light sheet illumination.

Buchmann Institute for Molecular Life Sciences (BMLS), Germany, Scientist, Dr Francesco Pampaloni, said, ‘With our project, we want to go the other way round by developing a top-down lithography method.’

According to the researchers, their proposed method has similarities with how semiconductor technology uses lithography. ‘Instead of the semiconductor and the photosensitive layer, which is illuminated by a mask, a hydrogel with photosensitive molecules is used. This is exposed to a thin laser light sheet using the microscopy technique invented by Professor Ernst Stelzer. This leads to the formation of branched-chain structures, polymers, that serve as a matrix for colonisation by living cells. The remaining, still liquid hydrogel is washed out.’

Pampaloni explained that, ‘This method will enable us to adjust the spatial structure and the stiffness with an unprecedented resolution so that we can create the same heterogeneous microstructures that cells find in natural tissues.’

Further, Pampaloni anticipates that this will lead to several prospects for bio-fabrication of intricate tissues and anatomical microstructures. It is also believed that production will be quicker and cheaper than current 3D printing systems.

The consortium is made up of researchers from Goethe University including BMLS, IBEC in Spain, Technion in Israel, Cellendes in Germany and Mycronic in Sweden.

The project is part of the European Union’s Future and Emerging Technologies Open Horizon 2020 programme and will receive total funding of €3.45mln, of which €700,000 will go directly to the team led by Pampaloni.