Cotton candy mishap leads to new way to model scar tissue

Sunday, November 1, 2015 - 7:07pm

Just before Halloween, the University announced that an unsuccessful attempt at making cotton candy inspired the discovery of a new bioengineering technique.

A University team, led by Biomedical Engineering Prof. Shuichi Takayama, announced in a press release last week they discovered a new method to model extra-soft silicone for cell research.

The team’s project studied scar tissue formation in soft-celled organs like the lung and liver, as the body recuperates from internal scarring caused by diseases such as diabetes and cancer.

“In general, our research group is concerned with using small tools to understand what happens in the body, by doing the experiments outside the body,” said Engineering graduate student Joseph Labuz, a member of the team. “This project works on measuring the forces exerted by cells, as well as the mechanical properties of tissue.’’

Their original plan was to position cells around tiny pillars of soft silicone that acted as scar tissue, then apply different treatments to the cells and measure the deformation of silicone as the cells expand and contract.

But to do so, the team first needed to figure out how to mold the soft silicone, a material known as Sylgard 527, into the desired shape — which is where the cotton candy came in. The team’s initial instrument of choice, hard epoxy molds, proved unviable because silicone pillars were so soft they disintegrated upon removal from the mold.

However, a chance encounter in the kitchen for a member of the team, Christopher Moraes, assistant professor of chemical engineering at McGill University, led to a new idea. Moraes worked on the team as a postdoctoral researcher at the University.

In the process of making an unsuccessful batch of cotton candy, Moraes noticed that the hard slab of candy he was left with captured every detail of the pan in which it was molded.

This fueled an idea to make a mold out of sugar, cast the Sylgard 527 in the candy mold and finally, immerse the mold water so it will dissolve, leaving only the silicon pillars.

“I actually wouldn’t describe it as a ‘Eureka’ moment, as much as a ‘hmm … that’s odd’ moment, before I threw away the candy disaster in disgust and went to bed,” he said. “I woke up the next morning with the idea of what that might mean in the lab. This accidental process happens quite frequently, but perhaps 99 percent of the ideas that I have end up failing.”

The team had by then spent nine months trying to find the right materials for their project through repeated trial and error — leaving them open to the new idea.

After testing Moraes’ conjecture with stunt glass, a common feature of Hollywood action films and an essentially sugar-based material, the team formulated the recipe for the perfect mold: a simple, sweet-smelling concoction made largely of sugar and corn syrup.

“For me, this project is unusual in that it really emphasizes the fun and surprise of doing science and engineering research, an aspect that is often overlooked when scientists reflect on their work,” he said. “I mean — who would have thought that candy-makers would have figured out the secrets needed to micro-fabricate tissues?”

Labuz echoed his sentiments, and said their project proves out-of-the-box thinking can often be useful for research.

“A lot of times, both people who work on research, and also people who don’t, imagine that research has to be done a certain way, and ideas can only come from big complicated textbooks and long equations and things like that,” he said. “But a lot of times the best ideas are the simplest or the most obvious ones.”

Takayama said the discovery will allow new avenues for cell-based research in modeling delicate processes.

“It is important technologically because it enables practical measurements of forces otherwise very difficult to perform,” he said.

For this reason, the team has decided not to patent the fabrication technique, first published earlier this year.

“That’s not to say that patents or being the first to publish or being recognized for being the first to discover something isn’t important,” Labuz said. “But at least the way our lab operates is, once we have an idea or technique down or validated, we are happy to share it with other people.”

Moraes said he hoped that the technique can also be leveraged beyond the field of science, suggesting that it could be used to make "smart" or "dynamic" candy that was customized to specific flavor profiles.

Moving forward, he still faced a personal challenge: figuring out how to make cotton candy successfully.

“My last attempt wasn’t nearly as horrible as my first, but still nowhere near the expert hand-pulled cotton candy product,” he said. “I might switch over to trying hand-pulled noodles first, which uses a similar pulling technique but seems to be a little more forgiving than candy.”