Malaria parasites contain tiny iron-rich crystals that rapidly jiggle and tumble inside the single-celled organism. Scientists have observed their motion for years — some antimalarial drugs work by disrupting the process by which they’re formed — but the mechanism behind their wild motion remained a mystery.
Now, a collaboration between the University of Utah’s John and Marcia Price College of Engineering and the Spencer Fox Eccles College of Medicine has revealed that these crystals are powered by a chemical reaction similar to the one in jet fuel.
The crystals are made of heme, a compound produced when the parasite consumes red blood cells. These crystals catalyze hydrogen peroxide breakdown; when they do, they release energy, enough to push the crystals far beyond what random thermal motion can produce. The resulting propulsion appears to help the parasite manage oxidative stress and safely store heme.
Tamara Bidone, assistant professor in the Department of Biomedical Engineering conducted the computational modeling that helped explain how and why the crystals move, working alongside Henry Fu, professor in the Department of Mechanical Engineering. The research team also included Postdoctoral Researcher Tomasz Skóra and Software Engineer Keith Carney, both from the Scientific Computing and Imaging Institute, who contributed key computational and software expertise.
The study, published in the journal PNAS, was led by Paul Sigala, associate professor of biochemistry in the Spencer Fox Eccles School of Medicine, and Erica Hastings, a postdoctoral researcher in his lab. “People don’t talk about what they don’t understand, and because the motion of these crystals is so mysterious and bizarre, it’s been a blind spot for parasitology for decades,” said Sigala.
To understand the motion, the research team paired microscopy with Bidone’s modeling. Live imaging captured the crystals’ trajectories, while modeling tested possible forces behind the motion. They used computational tools to first analyze and quantify the trajectories, looking at average distance traveled and step sizes, and then for building a Brownian motion model to see whether temperature alone could explain the behavior.
It couldn’t. As Bidone explains, the initial comparison showed “the data just didn’t align with what you’d expect from pure Brownian motion. The crystals weren’t only moving because of thermal fluctuations.” Instead, she said the trajectories clearly reflected “an interplay between the random thermal motion and an added, directed push,” hinting at an energy source inside the parasite.
By accounting for different environmental and physical factors like, viscosity, crowding, confinement, and interactions between the crystals, the model pointed toward hydrogen peroxide as the driver. Laboratory experiments confirmed that when oxygen levels dropped, the crystals slowed down, and isolated crystals placed in hydrogen peroxide started tumbling more dynamically on their own.
Mechanical engineering professor Henry Fu said the findings connect biology and engineering in a way many wouldn’t expect. He explained that hydrogen peroxide–powered motion is well known in microrobots, but researchers typically view it as something that works only in artificial settings.
“People generally wouldn’t think this kind of propulsion could operate inside the human body,” he says. “But this work shows the exact same mechanism is happening inside a parasite’s cells.”
The tumbling benefits the parasite, keeping heme crystals from clumping together, which improves the parasite’s ability to store heme safely. As Fu described it, the crystals’ movement even accelerates the decomposition of hydrogen peroxide, giving the parasite a survival advantage.
The discovery also opens opportunities for engineers working with nanoscale systems. Fu notes that as structures become smaller, Brownian motion dominates more strongly, and the heme crystals offer a rare real-world example of how tiny particles behave when chemical propulsion acts.
“Insights like this could help engineers design biologically inspired materials capable of adapting to their environment, especially at micro- and nanoscale levels,” Fu says.
Both Bidone and Fu emphasized how essential interdisciplinary collaboration was to the discovery. Bidone explains that the modeling depended entirely on experimental data, while the biology team needed theoretical tools to interpret what they were seeing.
“We couldn’t build the model without the experiments, and they couldn’t fully understand the system without the theoretical framework,” she says. “This kind of result only happens when the fields work together.”
Fu agrees, saying the project showed that “it truly takes everyone involved,” including contributors like Skóra and Carney whose computational insight supported the core findings.
“After carefully capturing the movies in the microscopy lab,” says Carney, “what you end up with is, depending on how densely packed the crystals are, either raw changes in pixel intensities over time or, if you can distinguish single crystals, thousands of erratic trajectories.”
“It’s a huge amount of data and there is still a long way from there to extracting the physical mechanism of motion in a complex biological fluid” says Skóra. “That was my and Keith’s contribution — to learn as much as we can about the nature of hemozoin motion from this big and irregular dataset”.
By blending computation, engineering, and cutting-edge microscopy, University of Utah researchers helped uncover the hidden engine powering the malaria parasite’s wobbling crystals, offering new insights for both malaria biology and future nanoscale engineering.