We cured pneumonia in mice by filling their lungs with swimming microrobots

When The Jetsons premiered in September of 1962, its visual design was dominated by midcentury hypermodernism. The aesthetic is precisely what you’d expect from creators in the 1960s imagining what the world might be like a hundred years in the future. It’s mostly the same, just more high-tech. That’s probably why, when we imagined the family unit of the future, it included a household robot named Rosie, who happily — or unhappily, depending on the episode — took care of all the domestic chores.

That view of robots largely persists in the public consciousness, with images of domestic robots vacuuming our houses, washing the dishes, and folding the laundry. We imagine them cleaning things the way that we clean things with washrags clutched in their metal fists.

While we’re still waiting for our very own Rosie, Fangyu Zhang from the Department of Nanoengineering and Chemical Engineering Program at the University of California San Diego, and colleagues, have developed a different sort of robot which cleans out lungs like a germ-killing Roomba. Their findings were published in the journal Nature Materials.

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Researchers wondered if they might have more success fighting off pneumonia infections if they took a more direct approach. That’s where their microrobots came in. A swarm of millions of microscopic, partially biological robots were deployed inside the lungs of mice in order to test whether they could eradicate the infection more effectively than conventional treatments.

“The microrobots are made of two parts. One is the microalgae which are capable of swimming in versatile mediums,” Zhang told SYFY WIRE. In this case, the versatile medium the microrobots encounter is an infection-riddled pair of living lungs. “The other part is the cell membrane-coated polymeric nanoparticles containing the antibiotics.”

Those nanoparticles are comprised of two main parts. The first is a polymeric core loaded full of antibiotics, and the second is a shell made of biological cell membranes. Scientists took the cell membranes of neutrophils, a type of white blood cells, and slipped them over the drug-filled cores like an autumn jacket.

The cell membrane outer covering works as both a set of armor and a disguise. It protects the antibiotic capsule inside from environmental hazards while also reducing immune clearance, allowing the microrobots to move freely in the lungs and find pathogens.

In experiments, the scientists used about 5 million microrobots for each treatment. While that might sound like a lot, it was actually much more efficient than conventional antibiotic delivery methods.

“Treatment with microrobots was more effective than an IV injection of antibiotics into the bloodstream. We proved that the IV injection required a dose of antibiotics that was 3,000 times higher than that used in the microrobots to achieve the same effect,” Zhang said.

What’s more, in the course of their experiments, every single mouse treated with microrobots was cured of pneumonia-causing bacteria and symptoms resolved themselves. By contrast, mice who did not receive microrobotic treatment were dead within three days.

The success of this system is due to the ways in which it’s different from previous treatment methods. When antibiotics are given orally or intravenously, they have to get into and navigate the blood stream in order to end up where they’re needed. As a result, only a portion of the administered antibiotics actually end up interfacing with the infection. The microrobots, however, can be delivered directly to the site of the infection and move around once inside, increasing the likelihood they’ll find a suitable target. Then, when they’re finished, they vanish into the proverbial night like 5 million miniature Batmans… Batmen… you get the picture.

“After the treatment, the algae can be digested and cleared by the immune cells, which also indicates our formulation is safe and biocompatible,” Zhang said.

Looking forward, the team hopes to better understand how the microrobots interact with the immune system as well as find out if their system might be effective at defending against other types of infections. Alas, there are plenty of steps remaining before this current work can make its way into clinical applications in people. Researchers still need to scale their system and test it on larger animal models before humans get their first crack at vacuuming their lungs out with microrobots.