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Spare parts from small parts: novel scaffolds to grow muscle



Researchers have for the first time incorporated the natural processes of embryonic development to build a material that can more naturally communicate with stem cells for effective tissue repair. The breakthrough offers hope to people suffering from injuries where their muscles cannot repair themselves due to trauma or disease, and our rapidly aging population.

Led by Richard Williams, Ph.D., from RMIT University, the scientists combined lab-made peptides with natural proteins and polymers to create a 3D hydrogel scaffold. The scaffold uses natural mechanisms to incorporate signals found in the natural developmental environment to support and engineer stem cells into muscle fiber.

“Our stem cells are at their best during development, where a scaffold drives them to produce all our tissues and organs; yet as people grow and age, they lose this ability and get a buildup of undesirable structures,” Dr. Williams explained. “So there is a real need for ways to repair and replace parts of the body as they wear out or become damaged, particularly as our population is now living longer.  

“Essentially, we made a scaffold that sends healthy signals to the cells to reorganize themselves to start to grow the small fibers that make up a healthy muscle. It’s like travelling back in time when our potential for tissue development and repair was at its best.”

Dr. Williams said it is a simple process to deliver complex structures inspired by the way nature pieces structures together during development, starting with only two cells.

“We have developed a simple, cheap, yet powerful toolkit that encourages different environments to let different tissues grow,” he said.

The material properties of natural tissues, like muscles, are complex and extremely difficult to mimic synthetically. Researchers have been producing “organizing” signals for years to understand how cells work but only in a flat, or 2D, environment.

“We have found a way to use the proteins present during embryonic development in a 3D scaffold, and use this extra dimension to potentially grow muscle,” Dr. Williams said.

The study, recently published in Biomacromolecules, showed that combining a hydrogel with these small proteins is easy and effective. In fact, just 24 to 72 hours after seeding the cells into the tissue, there was a noticeable reorganization of individual cells into the multicellular structures that go on to make up functioning muscle, the researchers reported.

A detail of the muscle tissue the researchers are replicating with their novel 3D material. Image courtesy of RMIT.

The RMIT researchers are now exploring how they can bioprint muscle with the stem cells already embedded to put nerves, blood vessels and muscles together into lab grown “spare parts.”

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DOI: 10.1021/acs.biomac.7b01632