Technology

Shrinky Dinks, nail polish, and smelly bacteria

In a lab on the fourth ground of MIT’s Constructing 56, a bunch of Massachusetts highschool college students gathered round a tool that measures conductivity.

Vincent Nguyen, 15, from Saugus, considered the occasions the fabric on their pattern electrode flaked off the second they took it out of the oven. Or how the electrode would fold weirdly onto itself. The large fails had been form of humorous, however discouraging. The scholars had labored for a month, experimenting with completely different supplies, and 17-year-old Brianna Tong of Malden puzzled in the event that they’d lastly gotten it proper: Would their electrode work properly sufficient to energy a microbial gas cell?

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The scholars secured their electrode with alligator clips, somebody hit begin, and the teenagers watched anxiously because the gadget looked for even the faintest electrical present.

Capturing electrons from micro organism

Final July, Tong, Nguyen, and 6 different college students from Malden Catholic Excessive College commuted between the lab of MIT chemical engineer Ariel L. Furst and their college’s chemistry lab. Their aim was to style electrodes for low-cost microbial gas cells — miniature bioreactors that generate small quantities of electrical energy by capturing electrons transferred from dwelling microbes. These units can double as electrochemical sensors.

Furst, the Paul M. Cook dinner Profession Growth Professor of Chemical Engineering, makes use of a mixture of electrochemistry, microbial engineering, and supplies science to handle challenges in human well being and clear vitality. “The aim of all of our tasks is to extend sustainability, clear vitality, and well being fairness globally,” she says.

Electrochemical sensors are highly effective, delicate detection and measurement instruments. Usually, their electrodes must be inbuilt exactly engineered environments. “Excited about methods of constructing units while not having a cleanroom is vital for developing with cheap units that may be deployed in low-resource settings below non-ideal situations,” Furst says.

For 17-year-old Angelina Ang of Everett, the challenge illuminated the importance of “coming collectively to problem-solve for a more healthy and extra sustainable earth,” she says. “It made me understand that we maintain the solutions to repair our dying planet.”

With the assistance of a youngsters’s toy referred to as Shrinky Dinks, carbon-based supplies, nail polish, and a sure smelly bacterium, the scholars received — actually — a trial-by-fire introduction to the scientific methodology. At one level, one in all their experimental electrodes burst into flames. Different outcomes had been extra promising.

The scholars took benefit of {the electrical} properties of a bacterium — Shewanella oneidensis — that’s been referred to as nature’s microscopic energy plant. As a part of their metabolism, Shewanella oneidensis generate electrical energy by oxidizing natural matter. In essence, they spit out electrons. Put sufficient collectively, and also you get just a few milliamps.

To construct bacteria-friendly electrodes, one of many first issues the scholars did was tradition Shewanella. They realized easy methods to pour a development medium into petri dishes the place the reddish, usually lake-living micro organism may multiply. The microbes, Furst notes, are a little bit smelly, like cabbage. “However we predict they’re actually cool,” she says.

With the proper engineering, Shewanella can produce electrical present after they detect toxins in water or soil. They may very well be used for bioremediation of wastewater. Low-cost variations may very well be helpful for areas with restricted or no entry to dependable electrical energy and clear water.

Subsequent-generation chemists

The Malden Catholic-MIT program resulted from a fluke encounter between Furst and a Malden Catholic mother or father.

Mary-Margaret O’Donnell-Zablocki, then a medicinal chemist at a Kendall Sq. biotech startup, met Furst by way of a mutual buddy. She requested Furst if she’d take into account internet hosting highschool chemistry college students in her lab for the summer season.

Furst was intrigued. She traces her personal ardour for science to a program she’d occurred upon between her junior and senior years in highschool in St. Louis. The daughter of a software program engineer and a businesswoman, Furst was casting round for potential profession pursuits when she got here throughout a summer season program that enlisted scientists in academia and personal analysis to introduce highschool college students and academics to elements of the scientific enterprise.

“That’s after I realized that analysis shouldn’t be like a lab class the place there’s an anticipated end result,” Furst recollects. “It’s a lot cooler than that.”

Utilizing startup funding from an MIT Vitality Initiative seed grant, Furst developed a curriculum with Malden Catholic chemistry trainer Seamus McGuire, and college students had been invited to use. Along with Tong, Ang, and Nguyen, individuals included Chengxiang Lou, 18, from China; Christian Ogata, 14, of Wakefield; Kenneth Ramirez, 17, of Everett; Isaac Toscano, 17, of Medford; and MaryKatherine Zablocki, 15, of Revere and Wakefield. O’Donnell-Zablocki was shocked — and happy — when her daughter utilized to this system and was accepted.

Furst notes that girls are nonetheless underrepresented in chemical engineering. She was significantly excited to mentor younger girls by way of this system.

A conductive ink

The scholars had been charged with figuring out supplies that had excessive conductivity, low resistance, had been a bit soluble, and — with the assistance of a suitable “glue” — had been in a position to stick with a substrate.

Furst confirmed the Malden Catholic crew Shrinky Dinks — a typical polymer popularized within the Seventies as a craft materials that, when heated in a toaster oven, shrinks to a 3rd of its dimension and turns into thicker and extra inflexible. Electrodes primarily based on Shrinky Dinks would value pennies, making it a great, cheap materials for microbial gas cells that might monitor, as an illustration, soil well being in low- and middle-income international locations.

“Proper now, monitoring soil well being is problematic,” Furst says. “You need to acquire a pattern and produce it again to the lab to research in costly tools. But when we’ve these little units that value a few bucks every, we are able to monitor soil well being remotely.”

After a crash course in conductive carbon-based inks and solvent glues, the scholars went off to Malden Catholic to determine what supplies they wished to attempt.

Tong rattled them off: carbon nanotubes, carbon nanofibers, graphite powder, activated carbon. Potential solvents to assist glue the carbon to the Shrinky Dinks included nail polish, corn syrup, and embossing ink, to call just a few. They examined and retested. Once they hit a lifeless finish, they revised their hypotheses.

They tried utilizing a 3D printed stencil to daub the ink-glue combination onto the Shrinky Dinks. They hand-painted them. They tried printing stickers. They labored with little squeegees. They tried scooping and dragging the fabric. A few of their electro-materials both flaked off or wouldn’t stick within the heating course of.

“Embossing ink by no means dried after baking the Shrinky Dink,” Ogata recollects. “In truth, it’s in all probability nonetheless liquid! And corn syrup had a bent to boil. Seeing activated carbon ignite or corn syrup boiling within the convection oven was fairly the spectacle.”

“After the electrode was out of the oven and cooled down, we might examine the conductivity,” says Tong, who plans to pursue a profession in science. “If we noticed there was a excessive conductivity, we received excited and thought these supplies labored.”

The second of reality got here in Furst’s MIT lab, the place the scholars had entry to extra refined testing tools. Would their electrodes conduct electrical energy?

A lot of them didn’t. Tong says, “At first, we had been unhappy, however then Dr. Furst advised us that that is what science is, testing repeatedly and typically not getting the outcomes we wished.” Lou agrees. “If we simply copy the information left by different students and don’t acquire and determine it out by ourselves, then it’s troublesome to be a professional researcher,” he says.

A few of the college students plan to proceed the challenge one afternoon per week at MIT and as an unbiased examine at Malden Catholic. The long-term aim is to create a field-based soil sensor that employs a bacterium like Shewanella.

By probability, the scholars’ very first electrode — made from graphite powder ink and nail polish glue — generated essentially the most present. One of many group’s greatest surprises was how a lot better black nail polish labored than clear nail polish. It seems black nail polish incorporates iron-based pigment — a conductor. The surprising win took a number of the sting out of the failures.

“They realized a really laborious lesson: Your outcomes may be superior, and issues are thrilling, however then nothing else would possibly work. And that’s completely effective,” Furst says.

This text seems within the Winter 2023 concern of Vitality Futures, the journal of the MIT Vitality Initiative.

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