30.10.2017 change 06.11.2017

Mussels inspire scientists who print tissues

Goose Barnacles and Mussels attached to rocks background Goose Barnacles and Mussels attached to rocks background

Mussels - and more precisely the substance that allows them to stick to rocks - inspired scientists. They are working on a hydrogel that mimics its properties. In the future, it will help in 3D tissue printing or tissue adhesion.

Bioprinting, or printing tissues in 3D technology, is a relatively new but thriving field. The difference between bioprinting and ordinary 3D printing is that biomaterial containing cells of suitable tissues is used for printing layers.

"The future is of course the printing functional tissues and organs, but this is still ahead" - explained Dr Małgorzata Włodarczyk-Biegl from the German INM Leibniz Institute for New Materials.

As noted, the requirements for bioprinting are much higher than for normal 3D printing. "The entire printing process must be compatible with cells so that they can survive the material stiffening process, and at the same time it must ensure that the shape of the tissue we print is maintained" - she said.

One of the most important challenges that bioprinting teams face is controlling the position of the cells and maintaining the shape of the printed tissue. Despite these difficulties, in January a group of Spanish scientists presented a prototype 3D bioprinter capable of printing human skin. According to the authors of the method, such skin can be used, among other things, for transplantation or in tests of cosmetics or chemicals.

In August, a team from the University of Oxford presented a new 3D printing method that allows to arrange various types of cells in stable shapes. The researchers placed the cells in microscopic droplets surrounded by a fatty membrane. Such structures - they argued - can be stacked in desirable, stable shapes in layers - one over the other.

"Many groups are currently developing biological inks that will be compatible with cells. These inks are usually hydrogels, gels composed of polymers suspended in water" - the researcher explained.

Dr. Małgorzata Włodarczyk-Biegun and her colleagues from the INM Leibniz Institute for New Materials are working on a hydrogel inspired by natural materials, specifically mussels.

"We develop polymers that mimic the natural proteins produced by mussels. These proteins allow mussels to strongly adhere to rocks, A mussel extends the foot releasing the protein, which hardens due to pH change or the presence of oxygen" - the researcher described.

"We are working on a material that stagnates and hardens precisely under the influence of pH changes or the presence of oxygen. Our material should have a liquid form to provide a very good environment for cells. The problem is how to make the material gelous as quickly as possible without affecting the cells, while maintaining the structure of the printed object" - the researcher said. The substance designed to enable rapid gelling of the material without harming the cells is inspired by the mussel proteins.

"Our material allows to obtain layers that contain different types of cells. This allows to build different types of tissue" - said Włodarczyk-Biegun.

In addition to the use in bioprinting, the substance can be used as a medical adhesive that connects tissues instead of traditional stitches. The substance works very effectively in the aquatic environment and in the presence of blood, so it could be used during internal operations and microsurgical procedures that require small and precise stitches.

This is the preliminary stage of research of the Prof. Aránzazu del Campo\'s team, in which Dr. Włodarczyk-Biegun works. The material is now being tested. "We already know that it allows to build stable structures and that it is biocompatible with cells, so when we introduce cells into it, they will be able to function. However, when printing, cells are subjected to high force, so now we must verify that they can survive the entire process" - described the researcher.

Dr Małgorzata Włodarczyk-Biegun presented the results of her research during the German edition of the conference "Science. Polish Perspectives - Meetup", which took place in Berlin in October. One of the media sponsors of the event was PAP - Science and Scholarship in Poland.

author: Ewelina Krajczyńska

editor: Anna Ślązak

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