PPG Scholars Gain Research Experience While Creating Chemistry Solutions

Every chemist, no matter how skilled, has reactions fail when they try to synthesize something new. When that happens, Luke Cerwin, an undergraduate student in Carnegie Mellon’s Department of Chemistry, turns to Ph.D. student Chloë Zimovets for advice.

“Chloë helped me learn that sometimes bad data is better than good data because it shows you that you don’t understand the full picture,” Cerwin said. “I can always discuss which directions we can go next.”

The strongest discoveries emerge when scientists work together. That sense of collaboration drives the Department of Chemistry’s PPG Scholar Teams program, where undergraduate and graduate students partner on research ranging from cleaning wastewater to developing potential new medical treatments.

Supported by a gift from the PPG Foundation and matching funds from the department, the program funded five summer teams — including Cerwin and Zimovets — where graduate students mentored undergraduate students on immersive research projects under the guidance of faculty members. Funds were used to support undergraduate and graduate student stipends as well as pay for chemicals and other supplies.

“There is no more impactful activity that a student can undertake than research,” said Bruce Armitage, professor and department head of chemistry. “The PPG Scholars program is the latest example of our approach to uplifting and rewarding our graduate students for the vital role they play in undergraduate research. Supporting our undergraduates, graduate students and faculty in this endeavor is central to advancing our knowledge of the world around us and training the next generation of scientists.”

This summer, the first cohort of PPG Scholar Teams conducted a range of research from investigating safer ways to treat people exposed to heavy metals to finding ways to remove antidepressants from wastewater. Their contributions could lead to potential real-world changes that improve human and environmental health.

Improving heavy metal treatments

Heavy metal poisoning affects millions of people worldwide, causing brain damage, kidney disease and increased risk of cancer. However, the standard treatment for severe cases, chelation, targets metals in the body indiscriminately. As the body tries to metabolize the metals during chelation, the treatment can lead to kidney and liver damage.

Cerwin and Zimovets work to make chelators safer and more effective.

“There is no safe threshold for lead levels, and the existing treatments are drugs that are painful, non-selective and don’t last long enough in the body to be effective,” Cerwin said. “Our goal is to create a drug that addresses all of those issues.”

With Zimovets’ guidance, Cerwin created a way to link chelators to a chain of peptides, collections of amino acids that are bound together. The human body makes its own peptides, so the body can absorb synthetic versions relatively easily. By attaching the chelators to synthetic peptides, Cerwin and Zimovets hope to target the chelators to specific metals in the body and make the chelators easier for the body to process.

Cerwin spent the summer finding ways to ensure that the chelators properly bound to the peptides. From there, he started testing to see if the peptides and chelators could effectively remove metals from a liquid solution.

“It’s a very ambitions problem, and there hasn’t been a good solution for it,” Zimovets said. “We successfully synthesized the family of peptides we wanted to, and now we're trying to figure out the best way to actually measure their metal chelating abilities.”

Cerwin will continue working with Zimovets on the project, testing the peptide bonded chelators. They hope to apply their treatment to Caenorhabditis elegans, a species of nematode, to ensure the treatment works in a living organism.

Cerwin and Zimovets are both part of Associate Professor Stefanie Sydlik’s lab. Sydlik said that through the PPG Scholars program, she has watched them both become better researchers.

“Chloë grew into her role as a mentor, and Luke gained confidence in his role as a researcher,” said Sydlik, who also had a second PPG scholars team of researchers working on materials used to repair bones. “It’s been a great program that encourages graduate students and undergraduates, hand in hand, working together to grow and make these really impressive scientific discoveries.”

Removing common drugs from wastewater

Millions of Americans benefit from antidepressant medications annually. As with many pharmaceuticals, small amounts of these compounds can pass through wastewater treatment systems and enter rivers and streams. Some of these medications, like Zoloft, can affect wild salmon’s health and development. Researchers are developing new technologies that protect aquatic ecosystems.

Undergraduate student Matthew McCowen and Ph.D. student Debojyoti Chakraborty create and analyze new ways to quickly and safely remove sertraline, the active ingredient in Zoloft, from water.

“It’s going to have pretty direct real-world applications,” McCowen said. “All of this information is going to be used to further a broader study in the Puget Sound to help with their wastewater treatment.”

McCowen and Chakraborty are part of the lab of Terrence Collins, Teresa Heinz Professor in Green Chemistry and director of the Institute for Green Science. Working with TAML catalysts, which were invented by Collins, the lab develops ways to remove micropollutants from wastewater without creating toxic byproducts. Researchers have successfully used TAMLs against contaminants including pesticides, dyes and pharmaceuticals.

With Chakraborty’s help, McCowen investigated how TAML catalysts break down sertraline and its byproducts completely. He also developed new ways to track the compounds created during the process. By the end of the summer, McCowen had identified both the amount of TAML catalyst and the reaction time needed to fully degrade sertraline in a water sample.

“When the antidepressant sertraline degrades, it leaves behind a stubborn byproduct called sertraline ketone that standard oxidation processes can rarely get rid of,” Chakraborty said. “Luckily, a new TAML and hydrogen peroxide treatment can break it down completely.”

McCowen and Chakraborty will continue refining the methods to improve their efficiency in detection and identify all of the compounds the reaction produces.

Collins said their research as part of PPG scholars has the potential to significantly help the environment.

“Funding undergraduate research is key to American leadership in building a sustainable future for humanity and for life in general,” Collins said. “Mathew and Debo are wonderful examples of how that leadership consolidates when it receives support from insightful companies like PPG. This is a wonderful collaboration for the two of them to learn from each other while advancing science at the same time.”

Producing the next generation of chemists

The PPG Scholar Teams program will fund undergraduate and graduate student work again in summer 2027, and the Department of Chemistry hopes to expand the program to include more teams.

“We’re immensely grateful for the PPG Foundation’s support of this program,” Armitage said. “Looking further down the road, we would love to see this program receive endowed funding so that it could continue indefinitely.”

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