Algae-Based Microrobots Deliver Life-Saving Drugs

Nanotechnology engineers at UC San Diego have developed microscopic robots, called "microrobots." They can swim around in the lungs, deliver medication, and be used to clear up life-threatening cases of bacterial pneumonia.

"Our goal is to do targeted drug delivery into more challenging parts of the body, like the lungs. And we want to do it in a way that is safe, easy, biocompatible and long lasting," says research co-leader Liangfang Zhang in a press release issued by UC San Diego. "That is what we've demonstrated in this work."

The engineers had previously developed drug-delivering microrobots that can be safely used in live animals to treat bacterial infections in the stomach and blood. Treating bacterial lung infections is the latest in their line of work.

"With an IV injection, sometimes only a very small fraction of antibiotics will get into the lungs. That's why many current antibiotic treatments for pneumonia don't work as well as needed, leading to very high mortality rates in the sickest patients," adds co-author Victor Nizet. "Based on these mouse data, we see that the microrobots could potentially improve antibiotic penetration to kill bacterial pathogens and save more patients' lives."

A paper is published in Nature Materials. Engineers report that the microrobots safely eliminated pneumonia-causing bacteria in the lungs of laboratory mice, and resulted in 100% survival. All mice treated with the microrobots survived past 30 days, while untreated mice died within three days.

The paper explains that the microrobots are made of algae cells, whose surfaces are speckled with antibiotic-filled nanoparticles. The microrobots leverage the native movement system of the algae cells to swim around and deliver antibiotics directly to the bacteria in the lungs.

The nanoparticles containing the antibiotics also contain biomaterials that absorb and neutralize inflammatory molecules produced by the bacteria and the body's immune system. This gives the microrobots the ability to reduce harmful inflammation, which makes them more effective at fighting lung infection.

"These results show how targeted drug delivery combined with active movement from the microalgae improves therapeutic efficacy," summarizes research co-leader Joseph Wang.

After treatment, the body's immune cells efficiently digest the algae, along with any remaining nanoparticles. Nothing toxic is left behind.

The engineers are persuaded that these findings highlight the attractive functions of algae-nanoparticle hybrid microrobots for the delivery of therapeutics to the lungs in intensive care unit settings. The research work will continue with more studies to validate the microrobot treatment, scaling up before testing in larger animals, and eventually in humans.

"We're pushing the boundary further in the field of targeted drug delivery," concludes Zhang.

This shows that nanoparticle-based medicine is promising and could have a real clinical impact in, say, a decade or two. And it’s worth bearing in mind that the longer-term medical potential of advanced nanotechnology, as described in Eric Drexler’s classic book "Engines of Creation," is huge.