IU Ph.D. student Xinyu Zhang, left, and professor Mark Cheng examine equipment in the lab. Photo by Liz Kaye, Indiana University
An electrical engineer who joined the Indiana University Indianapolis campus last semester is bringing his microplastics research to a new lab in the Hoosier State.
Mark Cheng, professor of biomedical engineering and informatics in the IU Luddy School of Informatics, Computing and Engineering in Indianapolis, is an expert on sensing technologies and instrumentation. This includes developing new methods to identify the concentration and composition of microplastics found in water.
Mark Cheng is a professor of biomedical engineering and informatics in the IU Luddy School of Informatics, Computing and Engineering in Indianapolis. Photo by Liz Kaye, Indiana University The work, which puts a twist on Cheng's year of experience on sensors in medical technology, received
"Microplastics are everywhere, even in the water we drink," Cheng said. "But before you can address the problem, you need to understand it. Identifying the exact types of microplastics in water is the first step toward solving the program."
Cheng will also serve as the director of the Advanced Sensing Group at the Convergent Bioscience and Technology Institute, one of two research institutes on the IU Indianapolis campus announced as part of the university's $250 million investment in the biosciences. The institute's mission is to drive interdisciplinary research and collaboration in the pursuit of innovative discoveries.
A persistent presence
According to Cheng, it's estimated that less than 10% of plastics are recycled. About 70% end up in landfills.
About 10% to 20% "simply break down in the environment, where they can persist for decades - entering the soil, the water and our food systems," he said.
An extreme example of microplastics in the environment is the "Great Pacific Garbage Patch," a massive accumulation of mostly plastic debris broken down into microscopic pieces and trapped by ocean currents between the West Coast and Hawaii.
Microplastics have also been found in the human bloodstream, reproductive organs and even the brain. They can also negatively affect many forms of wildlife.
Postdoctoral researchers Ziliang Zhang, left, and Leixin Ouyang calibrate the microplastics water sensor in Cheng's lab in Innovation Hall at IU Indianapolis. Photo by Liz Kaye, Indiana University
Cheng said the main uncertainties in the current research stem from the lack of reliable methods to measure the quantity and quality of microplastics in samples, including blood. Improving the ability to identify and measure microplastics in water should translate into better methods to identify and measure microplastics in the human body as well.
"It's surprisingly similar to the challenges that face medical researchers," Cheng said. "When you draw a blood sample, there's a lot of material you're not interested in. You need to find the biomarkers of interest and measure it in a high-throughput way. That's the same challenge we face with water samples."
His work combines engineering - pumping large volumes of water past high-speed cameras to capture images of microscopic debris - with software design that leverages artificial intelligence to rapidly identify and assess any plastics in the images.
"We use computer vision and vibrational spectroscopy to classify plastic types and build high-throughput inspection systems," Cheng said. "We are also developing algorithms to make detection more accurate and efficient."
Assessing the risk
Microplastics found in water often include polyethylene and polypropylene from packaging; synthetic rubber from tires; and polymers from thin plastic sheets used to improve crop growth in agriculture. Each type has different chemical additives and degradation patterns, with some likely posing greater health risks than others.
By classifying microplastics by size, shape and chemical composition, Cheng said, researchers can finally start to unravel the biggest and most harmful sources of these pollutants.
IU Ph.D. student Xinyu Zhang is seen through the tubes and wires that comprise the internals of the microplastics water sensor. Photo by Liz Kaye, Indiana University
"We may find that some microplastics are worse than others," he said. "This research will help policymakers take a more targeted approach to the issue."
Cheng's partners in the research include postdoctoral researchers Leixin Ouyang and Ziliang Zhang and Ph.D. students Xinyu Zhang and Rong Fu, who also joined IU from his previous institution, the University of Alabama, where they developed deep expertise in different aspects such as algorithm development, microfluidic design and sensor integration.
Although it's packed with cutting-edge technology, the researchers' prototype device for filtering and identifying microplastics resembles little more than a small black cube, not much larger than a desktop computer.Normally, it sits quietly on a bench in Cheng's lab, but it's also been tested in the field. Many of these tests have been conducted on waterways in Alabama, including the Black Warrior River and Mobile Bay, as well as Myrtle Beach in South Carolina. Some early prototype testing also occurred in Michigan.
Next, Cheng is eager to create more connections in Indiana and possibly conduct some local testing. He also wants to work with medical researchers to explore new research into microplastics in the body.
"I believe that good solutions require good data," he said. "Only once we've got the right information can we finally start to solve a problem."
