New lab-made substances mimic human tissue and could reduce/replace the use of animal-derived materials in research

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 group 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. Hydrogels’ properties make them very useful for biomedical research, as they mimic human tissue and allow cells to grow in the laboratory.

There are also man-made hydrogels that are used in a wide range of everyday products, from food and cosmetics to contact lenses and absorbent materials, and more recently in medical research to close wounds and replace damaged tissue. . Although synthetic hydrogels may work well as space-filling materials to promote tissue growth, they are insufficient to reproduce the complex properties of real human tissue.

However, in a research paper published in 2017, nature communicationsUNSW scientists explain how a new hydrogel made in the lab behaves like natural tissue and has many surprising properties with implications for medicine, food and manufacturing technology. I am.

Associate Professor Chris Killian, from the NSW School of Materials Science and Engineering and Chemistry, said the hydrogel material was made from very simple short peptides, which are the building blocks of proteins.

“This material is bioactive, meaning the encapsulated cells behave as if they were living in a natural tissue,” says Professor A. Killian says.

“At the same time, this material is antibacterial, meaning it prevents bacterial infections. This combination hits the sweet spot of a material that could potentially be useful in medicine. The material is also self-healing. “reconstituted” after being crushed, broken, or expelled from a syringe. This makes it ideal as an injectable material for 3D bioprinting and medical applications. ”

Surprising discoveries during lockdown

Dr Ashley Nguyen, a NSW Chemistry student and lead author of the paper, made the discovery using computer simulations during the COVID-19 lockdown. Nguyen was looking for molecules that self-assemble (molecules that arrange themselves spontaneously without human intervention) and he stumbled upon the concept of “tryptophan his zipper.” These are short chains of amino acids with multiple tryptophans that act as zippers to facilitate self-assembly and are called “Trpzips.”

“We were excited to use computer simulations to identify unique peptide sequences that have the potential to form hydrogels,” Nguyen says.

“Once we got back to the lab, we synthesized our best candidate and were excited to see it actually form a gel.”

Nguyen said the hydrogel discovery could provide an ethical alternative to widely used natural materials.

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

“Also, materials of animal origin are problematic for use in humans due to negative immune reactions. Using Trpzip shows potential in many areas where natural materials are currently used. Not only do we have synthetic materials that have the potential to outperform natural materials, but also in other areas such as clinical research. ”

real world results

To test the feasibility of Trpzip in biomedical research, A/Prof. Killian’s team partnered with researcher Dr Shaffer Waters from the School of Biomedical Sciences at UNSW Sydney University, and the study used Matrigel, a hydrogel taken from mouse tumors, to culture patient tissue.

“Matrigel has some disadvantages in research applications because it varies from batch to batch. Chemically defined alternatives could be cheaper and more uniform, which could be very beneficial for biomedical research.” That will prove to be the case,” says Dr. Waters.

Professor A/Killian pointed out that the natural materials business is a billion dollar industry and said the team is keen to explore avenues to commercialization.

“We believe that Trpzip hydrogels and materials like them offer a more uniform and cost-effective alternative to animal-based products. We believe that our materials will reduce the number of animals used in scientific research. If we can do that, it will be a huge accomplishment.”

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