Sometimes a technology comes along that, seemingly, fits in seamlessly with the complex system of the human body.

Cue the introduction to a team of scientists from the ANU Research School of Chemistry and their super-strong gel that can recreate human flesh and other parts of the body, and can even heal itself and change shape. The team’s study, which involved rigorous experiments to test these features in the gel, has been published in the prestigious international journal Advanced Materials.

The team say the hydrogel could enable a new class of medical implants, or artificial muscles for next-generation robots that could one day swim.

Hydrogels are gels with a high water content and used in a range of products, including contact lenses.

Lead senior researcher Associate Professor Luke Connal says the new hydrogel's dynamic chemical bonds give it features unlike any other materials previously reported.

“With the special chemistry we’ve engineered in the hydrogel, it can repair itself after it has been broken, like human skin can,” he says.

“There’s potential for the material to be used as a replacement for skin, much like a Band-Aid.

“Our hydrogels' ability to self-heal, as well as its flexibility and strength, make it an ideal material for wearable technology and various other biomedical devices.”

There are precedents of self-healing material around the world, but these materials are not strong, Associate Professor Connal says.

“Usually, the features of self-healing and strength counteract each other,” he says.

“Our gel could be used to replace damaged cruciate ligaments. If someone has done their knee we could make materials that are strong enough to withstand forces acting on it. Furthermore, if the ligament-replacement breaks it could heal itself over time.”

Dr Zhen Jiang, a co-researcher and Postdoctoral Fellow, says the new shape-changing gel could be used to build robots with enhanced abilities by using temperature control to make artificial muscles that contract and expand.

“Hydrogels are usually weak, but our material is so strong it could easily lift very heavy objects,” he says.

“This makes our hydrogel suitable for artificial muscles in what we call ‘soft robotics’.

“Our hydrogel responds to temperature control within seconds, compared to other hydrogel’s response time of up to 10 minutes.”

Dr Jiang says the dynamic chemical bonds that the team engineered into their hydrogel enabled it to change quickly on demand, as would be required by an artificial muscle.  

“In the last decade, there has been an increasing interest in soft robotics, which can be employed to do incredible tasks that humans are unable to perform,” he says.

“Stimuli-responsive hydrogels represent a new class of soft materials that are highly desirable to be considered for this application,” he says.

Dr Jiang says the gel could be used when building autonomous robots specially equipped for search-and-rescue operations or those that could support the elderly and people with disabilities.   

“Soft robots may assist with the creation of automated ‘suits’ that could be used to rehabilitate patients recovering from injuries,” he says.

“If we could design an autonomous robot fitted with a camera to be capable of swimming into a spot where it’s not safe for a human, we could potentially make a real positive difference to these types of operations.

“In a lot of science fiction movies, we see the most challenging jobs being done by artificial humanoid robots. Our research has made a significant step towards making this possible,” he says.

Dr Jiang had the inspiration for the new hydrogel from one of his PhD projects.

“We anticipate that researchers working on the next-generation of soft robots will be interested and excited about our new way of making hydrogels,” he says.

The team can make the hydrogel with simple and scalable chemistry. They will develop a 3D printable ink based on the hydrogel.  

Associate Professor Connal says the sky is the limit with their invention, and they are keen to work with industry to develop the hydrogel for a range of commercial products that would benefit society.

“It’s entirely feasible that, with the right kind of investment and support from industry, we could see our gel being used as medical implants and in soft robotics within the next five to 10 years,” he says.

“Watch this space. I’m excited to see what the future holds for our work.”