Eradicating Microplastics with Magnetic Nanotech

In the last few decades, an abundance of information has come to light about the chemicals we use in cookware, food packaging, and a host of other daily products. Microplastics, PFAS, and PFOS have been dubbed “forever chemicals” due to the inability of the environment and our bodies to break them down or remove them — and the public is becoming increasingly concerned at the implications this has for our health and our planet.

Assistant Professor of Physics Kristen Repa, alongside undergraduate students including Ryan O’Connor and Avery Di Iulio, is working on a way to remove these chemicals from water.

“They’re very harmful in small quantities, and they can cause a multitude of health problems. And they’re found pretty much everywhere. We find them in the body, you find them in our food, in plants, they’re in animals — they’re just everywhere,” said Di Iulio.

Some health risks associated with these chemicals include thyroid disease, fertility problems, a weakened immune system, fetal developmental effects, and increased risk of cancer, to name a few.

As such, legislators are working to cease the use of these chemicals in manufacturing, and researchers are exploring ways to get rid of those already in circulation. One potential method is the use of magnetic nanoparticles, which Repa and her team have spent the last few years developing.

“Nanoparticles refers to the size. Nano is ten to the negative nine, or one billionth. So if you took a human hair and cut it down about 100,000 times, that’s the size of the particles. They’re little tiny magnets,” Repa explained.

“So if you take something like a refrigerator magnet and you put that around the particles, they will dance for you. But you take the magnet away and they go back to sitting on their own. Their (ferro)magnetism doesn’t affect each other because they’re too small.”

What this means is that the particles can be designed with special coatings to attract contaminants. So, when they are added to contaminated water, they’ll attach to targeted chemicals. When an external magnet is brought near, the particles — with the targeted chemicals now attached — will attract to the magnet, leaving behind purified water.

These nanoparticles can be used in a whole host of applications, including cancer treatment (hyperthermia) and enhancing MRI scans. While those use cases are widely studied already, Repa and her team found water purification to be much less covered.

O’Connor, who recently graduated in May of 2024, has spent three semesters working with Repa to advance this research.

“During the summer of my freshman year and going into my sophomore year, we focused on ways that we could create the particles themselves,” he said. “One method we tried was called chemical precipitation, which is what I mostly focused on for two years.”

“Then we started looking for ways that we could pivot the project from just making the particles to actually using them. So we started testing on E.coli.”

“That took a couple different trials, but eventually we came up with something that worked beautifully. So we’re like all right, this is a relevant target contaminant, especially in our area. But again, it’s also pretty well studied,” said Repa.

“So then I started reading a little bit more and found that forever chemicals are a huge problem. So we start thinking, how can we use these nanoparticles to get rid of forever chemicals in our water?”

Di Iulio, who is entering her sophomore year in the fall, has joined the team this summer to figure out just that.

“Avery is brand new, but has been doing some deep dives and has some really amazing ideas that I never would’ve thought of,” said Repa. “I’ve had to reference my graduate level textbooks to find answers to some of the questions that Avery has asked me so far.”

“It’s really interesting to me,” added Di Iulio. “While I was doing readings and literature searches last week, I was definitely reminded of why I chose this major. I think I’d be interested to go further into this research in graduate school eventually.”

If their work is effective and efficient, Repa’s team could eventually connect with engineers and local water authorities on upscaling their method into real-world application, purifying local drinking water of these dangerous chemicals. However, that stage would still be several years away.

“This is graduate level stuff. It’s really high-quality research, and these students really rise to the occasion,” Repa said. “Anybody who says that undergrads can’t do quality research just needs to come take a look at what our students are doing here.”

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