New biomaterial could change the way human tissue can be grown in the lab

Scientists at UNSW Sydney have developed a new material that could change the way human tissue is grown in the lab and used in medical procedures.

The new material belongs to a family of materials called hydrogels, which are the essence of life’s ‘squishy’ substances found in all living things, such as animal cartilage and plants such as seaweed. The properties of hydrogels make them very useful in biomedical research because they can mimic human tissue, allowing cells to grow in a laboratory.

There are also man-made hydrogels that are used in a wide range of applications, from food and cosmetics to contact lenses and absorbent materials, and more recently in medical research to seal wounds and replace damaged tissue. Although they can function adequately as space fillers that allow tissue growth, synthetic hydrogels fall short in recreating and encouraging the complex properties of real human tissue.

But in a research paper published today, Dr Nature communicationScientists at UNSW have described how a new lab-made hydrogel behaves like natural tissue, with a number of surprising properties that have implications for medical, food and manufacturing technologies.

Associate Professor Chris Killian, from UNSW’s School of Materials Science and Engineering and School of Chemistry, said the hydrogel material is very simple, made from small peptides, which are the building blocks of proteins.

The material is bioactive, meaning that the encapsulated cells behave as if they were living in natural tissue.”

Chris Killian, Associate Professor from UNSW’s School of Materials Science and Engineering and School of Chemistry

“At the same time, the material is antimicrobial, meaning it will prevent bacterial infection. This combination puts it in the sweet spot for materials that could be useful in medicine. The material is self-healing, meaning it will reform. “After being squished, after being fractured. , or after ejection from a syringe. This makes it ideal for 3D bioprinting or as an injectable material for medicine.”

Amazing discovery in lockdown

Ashley Nguyen, a PhD student at the UNSW School of Chemistry and first author of the paper, made the discovery during the Covid 19 lockdown using computer simulations. Ms Nguyen was looking for molecules that self-assemble – where they arrange themselves spontaneously without human intervention – and stumbled upon the idea of ​​the ‘tryptophan zipper’. These are short chains of amino acids with multiple tryptophans that act as zippers to promote self-assembly, termed “Trpzip”.

“I was excited to use computational simulations to identify a unique peptide sequence that could form a hydrogel,” Ms. Nguyen said.

“After we got back to the lab, I synthesized the top candidate and was thrilled to see that it actually formed a gel.”

Ms Nguyen said the discovery of this hydrogel has the potential to be an ethical alternative to widely used natural materials.

“Natural hydrogels are used everywhere in society—from food processing to cosmetics—but require harvesting from animals, which raises ethical concerns,” she says.

“Furthermore, animal-derived materials are problematic for human use because of the negative immune response that occurs. With Trpzip, we have a synthetic material that not only shows potential in many areas where natural materials are currently used, but may even surpass them. among others, such as clinical research.”

Real world results

To test the efficacy of Trpzip in biomedical research, A/Prof. Dr. Killian’s team researchers. Shafag Waters at UNSW Sydney’s School of Biomedical Sciences, who in her research uses Matrigel – a hydrogel harvested from mouse tumors – to culture patient tissue.

“Matrigel has some disadvantages in research use because each batch is different. A chemically defined alternative could be cheaper and more uniform, which would prove extremely beneficial for biomedical research,” said Dr. Waters.

A/Professor Killian notes that the natural materials business is a billion-dollar industry and says the team is keen to explore commercialization avenues.

“We think that Trpzip hydrogels and similar materials will provide a more uniform and cost-effective alternative to animal-derived products. It would be a great result if our material reduces the number of animals used in scientific research.”

The next phase of research involves partnering with industry and clinical scientists to test the utility of Trpzip gels in tissue culture and explore applications that highlight its unique kinetic properties, such as 3D bioprinting and stem cell delivery.