Could magnetic bacteria be used to deliver cancer therapies to where they are most needed in the body?

To find out, 2025 Schmidt Science Fellow Lucia Brunel has pivoted from the materials science focus of her PhD at Stanford University to the robotics lab at ETH Zürich.

As our 2025 Cohort embarks on the second convening of their Science Leadership Program, co-hosted by Stanford University and UC Berkeley, Lucia explains what it has been like to cross disciplines and continents to pursue her ambitious, interdisciplinary research.

Lucia Brunel has been fascinated by materials and their properties for as long as she can remember.

“As a child, I was always concocting strange combinations of materials with whatever I could find in the kitchen and then storing them in the freezer amongst the frozen vegetables, to my parents’ chagrin,” she smiles.

But what really ignited her research career was seeing first-hand how those materials could be applied to make a real-world difference for patients.

During her PhD, she shadowed eye surgeons as they operated on patients with corneal blindness, inspiring her research on bioprinting artificial corneas to restore vision on demand.

So far in her career, Lucia has pivoted between disciplines not just once, but twice, while crisscrossing between Europe and the US.

As a Northwestern University chemical engineering graduate, she hopped across the pond to venture into biomaterials and tissue engineering at Cambridge.

She did her PhD back in the US, at Stanford University.

As a 2025 Schmidt Science Fellow, she has pivoted again, from biomaterials into robotics, returning to Europe for a postdoc at ETH Zürich.

“The Schmidt Science Fellowship has been an amazing opportunity to allow me to take really big intellectual risks, to dream up big ideas that are unconventional, and to just go for them. It’s so exciting to be given permission, even encouraged, to evolve and redefine ourselves as scientists.”

Among the gadgets and machinery of ETH’s Medical Microsystems Lab, Lucia works on ‘living therapeutics’.

These are genetically engineered, drug-carrying bacteria that can be controlled from outside of the body using magnets.

“What makes these living therapeutics different from conventional treatments is that they don’t just passively carry a drug or payload, but rather they can also sense and decide and act in a more autonomous way.

“And in this way, we hope to more effectively get that drug or payload to where it belongs,” explains Lucia.

A muddy puddle might seem an unlikely origin for such futuristic science.

But it was within a sample of Italian bog sediments in 1963 that an unusual group of bacteria were first discovered.

Viewed under the microscope, they were all pointing in one direction: towards the North Pole.

It turned out that the microbes – known as magnetotactic bacteria – contain magnetic crystals that allow them to orient to the Earth’s magnetic field lines.

This enables them to swim in one direction, helping them to navigate more efficiently to their favourite low-oxygen environments at the bottom of ponds and bogs, while avoiding getting stuck on barriers in the sediments as they travel.

“We took inspiration from these magnetotactic bacteria, which are kind of like nature’s robots, to also engineer bacteria-based micro robots that can be used to deliver therapeutics, especially for cancer,” explains Lucia.

Some tumors have a necrotic core, which essentially means they are dying from the inside outwards.

Dead tissue contains very little oxygen, so magnetotactic bacteria, which follow gradients of high to low oxygen, have a natural ability to find their way to the center of tumors.

“The challenge with conventional bacteria-based cancer therapy is that when the bacteria are systemically applied to the body, they’re too far away from the tumors.

“They’re not localized at a high enough concentration to efficiently reach and deliver their cargo, the drugs, to the tumor,” explains Lucia.

“So that’s where this magnetic actuation aspect comes into play, of using magnetic control to localize them at the tumor tissue so that their innate system can take over and produce this positive therapeutic effect.”

Ultimately, Lucia and team envisage using technology similar to Magnetic Resonance Imaging (MRI) to localize the drug-carrying bacteria to exactly where they are needed in cancer patients.

So what has it been like to start her postdoc in a new country, a new discipline and a new lab?

“It requires a lot of adaptability and being comfortable with ambiguity.

“But it’s been an exciting chance to engage with people from all different backgrounds and life experiences.

“I’ve also found it interesting how different policies and priorities in countries influence the types of research directions that labs choose to pursue,” Lucia says.

Looking ahead, Lucia intends to bring together her interdisciplinary postdoc and PhD expertise to create artificial, self-healing organs that could be used for transplantation.

“I want to synergize these different fields to develop bioengineered organs that are self-regulating.

“I hope to design tissue-engineered constructs with integrated microtechnologies that can autonomously sense and adjust to stress signals in the body, such as inflammation or disease.”

And in the more immediate future, she is looking forward to her next Schmidt Science Fellows Senior Leadership Program (SLP) this month: “This will be my first time back in the US since I left for my postdoc last year, and coming back to Stanford will feel like coming home.

“It was a place where I grew so much as a creative scientist and leader. And the environment in the San Francisco Bay Area is just so vibrant and innovative,” Lucia says.

“I think we’ll have a lot of interesting discussions as a cohort as we reflect on the broader impacts and applications of our work beyond the ivory tower of academia,” she adds.

At the first SLP, she was excited to meet the other Fellows in person and to find herself part of a supportive, engaging and dynamic community.

“What was also really cool was engaging with this toolkit of skills – communicating across disciplines, perseverance, risk-taking and leadership in science – that are useful not just for my postdoc but really for the rest of my career and life,” she adds.

“The Schmidt Science Fellowship has been an amazing opportunity to allow me to take really big intellectual risks, to dream up big ideas that are unconventional, and to just go for them. It’s so exciting to be given permission, even encouraged, to evolve and redefine ourselves as scientists.”