Eden Tanner coats nanoparticles in liquid salts for targeted drug delivery

Chemist Eden Tanner didn’t recognize her own disability for many years. She had always been more fatigued than others; as an undergraduate at the University of New South Wales, she could hardly stay awake during lectures and needed naps throughout the day. Despite her challenges, one of her professors invited her to join their lab, and that research sparked an interest in what would become the focus of her career: ionic liquids.

These unique compounds are bulky and asymmetric, which prevents them from fitting together. “It’s like a forbidden love story between the cation and the anion,” says Tanner, who heads a lab at the University of Mississippi. “They desperately want to align their charges, but they can’t, so they end up being liquid.” These liquid salts can make strong ionic bonds with other molecules, which allows them to be used in many applications of chemistry, including synthesis and energy production.

Tanner continued researching ionic liquids as a graduate student at the University of Oxford. But during her final year, her symptoms reached a breaking point. After pushing herself to run a half-marathon, she couldn’t get out of bed for a week, and even everyday tasks like showering became difficult, as did research. Despite her condition, Tanner didn’t apply for formal accommodations at Oxford due to the unclear process, but her adviser was understanding and allowed her to take breaks when she needed to rest during the workday.

Not until Tanner began her postdoctoral research at Harvard University was she diagnosed with dysautonomia, a disorder of the autonomic nervous system that can cause issues with regulating one’s blood pressure and heart rate. She began intermittently using a motorized scooter, which helped alleviate her symptoms. With a diagnosis in hand, she also asked Harvard to provide anti-fatigue mats to help her stand at her lab bench for longer periods of time and to install automatic doors to make navigating her work environment easier with her scooter and without overexerting herself. But the university didn’t install the latter until 2 weeks before she left for the University of Mississippi.

Tanner might have struggled to receive proper accommodations during her postdoc, but her research still flourished. At Harvard, she combined her knowledge with the bioengineering perspective of her adviser, Samir Mitragotri, to determine how to use ionic liquids in a groundbreaking way: for targeted drug delivery.

Certain medicines, like chemotherapy, need to reach specific places in the body to be most effective and avoid unwanted side effects. Scientists have tried to use nanoparticles for targeted drug delivery, but the body’s barriers hinder them. So Tanner coats nanoparticles with ionic liquids that are similar in chemical composition to fatty acids or sugars. The liquid salts are then able to interact with the body in ways that mimic natural biological processes while simultaneously helping the particles reach their target tissues. There, the coating breaks down to release the medicine in a more controlled way than actual fats or sugars could.

“Her ideas are providing a new direction to the field,” Mitragotri says. “She has made tremendous progress.”

Tanner’s team is continuing to explore how to use ionic liquids in biomedical applications and has made recent breakthroughs. Previously, nanoparticles could be delivered to the brain only through injections to the central nervous system or by drilling into the skull and injecting into the brain itself. But Tanner’s team has developed a way to coat nanoparticles with ionic liquids resembling fatty acids; these coated nanoparticles can bind with red blood cells, hitching a ride through the blood-brain barrier. This method could help antiretroviral therapies, which are often blocked by this barrier, get to the brains of people with HIV and prevent cognitive symptoms.

The group is also studying sugar-like ionic liquids that can hitch a ride on a type of white blood cell called a macrophage, which is taken up by sugar-hungry breast cancer tumors. This ability could help them deliver cancer medications directly into the tumors without hurting healthy breast cells.

Tanner had the opportunity to build her lab from the ground up, so she incorporated accessibility from the start. Her lab features height-adjustable lab benches and automatic doors—features that make the lab more accessible not only to her but also to any scientist who might work there, removing barriers for potential future chemists. “It’s critical that we have disabled people be scientists because they bring an experience and perspective to the table that otherwise wouldn’t be there,” she says.

Tanner also has Cocoa, her service dog, who’s trained to sense when Tanner is close to overexerting herself. With Cocoa nearby, Tanner rarely needs to use her scooter, which makes her disability invisible to others. Many people assume she’s not disabled because that’s what they expect of a successful scientist, she says.

“It’s incredible to me how difficult it is for people to see a scientist and disability in the same person,” Tanner says.

That’s why Tanner is open about her identities as both disabled and queer. She’s the first openly queer faculty member in her department and often talks about her experiences being a first-generation university student.

Her openness has attracted scientists from a variety of underrepresented backgrounds to her lab. “I have a large team of people that I work with, several of whom are disabled, others of whom hold other identities that marginalize them in science,” she says. She wants everyone to feel welcome in chemistry.

“The students absolutely adore her,” says Abby Boyd, a chemist at the University of Mississippi and one of Tanner’s colleagues. “She really tries to promote a sense of belonging in chemistry,” Boyd says. “She tries to highlight that anybody can be a chemist.”