How jelly is playing a role in the creation of a substance that can mimic natural skin

Researchers use a jelly dessert to demonstrate how ions move in hydrogels. (Kai Jacobson/UBC Faculty of Applied Science)

A group of scientists is working to design a material that can mimic the ability of human skin to sense touch, and they're using a dessert popular with children and hospital cafeterias to do it.

It sounds futuristic, but the research being conducted at the University of British Columbia would offer a wearer of a prosthetic arm or robotic hand a more natural, comfortable feel.

Most so-called "smart skins" are made of metals and plastics, but some, called ionic skins, are made of more flexible materials.

These hydrogels use ions to carry an electrical charge, meaning when they're touched, the "skin" can generate voltages. This was known, according to a news release from UBC summarizing the team's peer-reviewed work that was published Thursday, but what was unclear is how this happened.

So a then-master's student in the biomedical engineering program at the University of British Columbia came up with a way to incorporate different sized hydrogel sensors into the skin.

The student, Yuta Dobashi, then worked with others in the school's physics and chemistry departments to apply magnetic fields. What this did was allow them to monitor how the ions moved.

And to demonstrate this movement, they used an unlikely substance: a jelly dessert, similar to what kids might take to school as a lunchtime treat, or what a hospital might serve its patients.

"When pressure is applied to the gel that pressure spreads out the ions in the liquid at different speeds, creating an electrical signal," Dobashi said in the UBC news release. Dobashi is now completing his PhD in Toronto, but started the work while getting his master's.

Because positive and negative ions, contained in salt inside the sensors, move at different speeds, "this results in an uneven ion distribution, which creates an electric field," he said.

This answered the "how" question scientists had.

For those less familiar with the concept, the researchers said what it means is that these hydrogels used in ionic skins actually work in a similar way to human skin. Ions move then, too, in response to pressure.

It's exciting news for those who see the implications of the work.

According to an electrical and computer engineering professor at UBC who oversaw the work, it means sensors could be created that would be able to interact with the nervous system.

"You can imagine a prosthetic arm covered in an ionic skin. The skin senses an object through touch or pressure, conveys that information through the nerves to the brain, and the brain then activates the motors required to lift or hold the object," John Madden said.

"With further development of the sensor skin and interfaces with nerves, this bionic interface is conceivable."

Another way the science could be used is to monitor a hospital patient's pulse, blood pressure and temperature, rather than the systems used in hospitals currently.

At some point too, these jelly-like materials could be used for implants such as artificial knees and hips, and they could even release drugs based on how much pressure it senses.

The research was published in Science, an academic journal published by the American Association for the Advancement of Science that has been around since the late 1800s. 

 

Study lead author Yuta Dobashi, a graduate of UBC's master in biomedical engineering program, is shown. (Kai Jacobson / UBC Faculty of Applied Science)