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Babesiosis is an infectious disease that manifests like malaria and spreads like Lyme disease. Once rare in the United States, it is now becoming more prevalent, particularly in the Northeast, Mid-Atlantic, and Upper Midwest.

To help scientists learn more about babesiosis, researchers at Carnegie Mellon University developed a new platform for monitoring the infection in red blood cells.

The disease is caused by the parasite Babesia microti, which lives in the blood of rodents. It is transmitted when a tick bites an infected rodent and then bites a human. The parasite enters the bloodstream, infecting and damaging red blood cells.

Early and accurate diagnosis is critical for available treatments. Babesiosis can be asymptomatic or cause flu-like symptoms, which can be severe in older and immunocompromised people.

The parasite's mechanisms of transmission and infection are not well-understood. In Advanced Science, Tagbo Niepa and collaborators a microfluidic system that can be used to study Babesia microti.

It is challenging to cultivate a parasite outside the host system, so traditional methods for the study of infectious diseases rely on animal models. "We wanted to make a tool in which the parasite can reside and remain viable, so that it can be studied in vitro," says Niepa, associate professor of chemical engineering and biomedical engineering.

The Niepa μBiointerface Lab designs microfluidic platforms to cultivate microorganisms near native conditions. Microorganisms behave differently in laboratory conditions than in natural environments, which has been a significant limitation for in vitro experiments.

To better study the life cycle of Babesia microti, researchers created a platform that maintains the whole blood microenvironment for the parasite. Collaborators include Chao Li, a research scientist in the Niepa μBiointerface Lab at the time of the study, and Danielle Tufts, assistant professor of infectious diseases and microbiology and immunology at the University of Pittsburgh.

Their technology functionalizes the hydrophobic and hydrophilic properties of a surface. By precisely placing oil and water, they can fabricate a microscopic channel, just big enough for a single layer of red blood cells.

"You can observe the monolayer of cells and see the infection dynamics of Babesia over time," says Niepa. Because the open microfluidic system offers better physical and optical access to samples than closed-system microfluidic platforms, scientists can assess Babesia microti in individual cells.

The platform makes it easier to identify the parasite, measure the density of the parasite in the blood, and track damage to infected red blood cells. Niepa and collaborators stained Babesia microti so that they are fluorescent in confocal microscopy images, offering a clear contrast with red blood cells.

Niepa is working to integrate the platform with automated device operation, imaging, and AI-powered image analysis. High-resolution confocal images are expensive and require days of data collection compared to the quick and inexpensive test used in hospitals. In about five minutes, a medical provider can use a standard microscope to look for Babesia microti in a single-droplet blood smear.

Niepa sees the potential for AI to optimize their more advanced process, increasing its speed of detection and providing the medical community with more information about the level of infection.

"There's much more characterization to do," says Niepa. For example, while Babesia microti is known to infect rodents and humans, the deer that carry and spread ticks are not infected. "This comes with some interesting biological questions that will be easier to study in our in vitro platform than in animal models."

Cell concentration in a blood sample diminishes naturally over time, and in Niepa and Li's system, samples last for 72 hours. The Niepa μBiointerface Lab is working on platform enhancements that will allow them to assess the viability of the parasite for a week, superseding the state-of-the-art platform.