Small swimming robots treat fatal pneumonia in mice!

Small swimming robots treat fatal pneumonia in mice!

Nanoengineers at the University of California, San Diego have developed microscopic robots, called microbots, that can swim into the lungs and deliver and use drugs to clear life-threatening cases of bacterial pneumonia.

In mice, the microbots safely eliminated pneumonia-causing bacteria in the lungs and resulted in 100% survival. By contrast, all untreated mice died within three days after infection.

The results were published on September 22 in nature materials.

Microbots consist of algae cells whose surfaces are strewn with nanoparticles filled with antibiotics. The algae provide locomotion, allowing the microbots to swim around and deliver antibiotics directly to more bacteria in the lungs. The antibiotic nanoparticles consist of small biodegradable polymer pellets encased in the membranes of neutrophils, a type of white blood cell. What sets these cell membranes apart is that they absorb and neutralize inflammatory molecules produced by bacteria and the body’s immune system. This gives the tiny robots the ability to reduce harmful infections, which in turn makes them more effective in fighting lung infections.

This work is a joint effort between the laboratories of nanoengineering professors Joseph Wang and Liangfang Zhang, both at the University of California, San Diego Jacobs School of Engineering. Wang is a world leader in micro and nanorobots research, while Chang is a world leader in the development of nanoparticles that mimic cells to treat infections and diseases. Together, they pioneered the development of small drug-delivery robots that could be used safely in live animals to treat bacterial infections in the stomach and blood. Treatment of bacterial lung infections is the latest in their field.

“Our goal is to deliver targeted drugs to more challenging parts of the body, like the lungs. And we want to do that in a way that’s safe, easy, biocompatible, and long-lasting,” Zhang said. “That’s what we showed in this work.”

The team used the tiny robots to treat mice severely and fatally from pneumonia caused by the bacteria Pseudomonas aeruginosa. This type of pneumonia usually affects patients who receive mechanical ventilation in the intensive care unit. The researchers administered the microbots into the lungs of mice through a tube inserted into the windpipe. The infection was completely gone after one week. All mice treated with microrobots survived the past 30 days, while untreated mice died within three days.

Treatment with microrobots was more effective than intravenous injections of antibiotics into the bloodstream. The latter required a dose of antibiotics 3,000 times higher than that used in microbots to achieve the same effect. For comparison, a dose of microrobots delivered 500 nanograms of antibiotics per mouse, while an IV syringe delivered 1.644 milligrams of antibiotics per mouse.

The team approach is very effective because it puts the drug where it is needed instead of spreading it to the rest of the body.

“These results show how targeted drug delivery combined with the energetic movement of microalgae improves therapeutic efficacy,” said Wang.

“With intravenous administration, sometimes a very small portion of the antibiotics get into the lungs. That is why many current antibiotic treatments for pneumonia do not work as well as they should, resulting in very high mortality rates in the sickest patients,” he said. Victor Nizet, MD, professor at the University of California, San Diego School of Medicine and the Skaggs School of Pharmacy and Pharmaceutical Sciences, is a study co-author and physician and collaborating scientist with Wang and Zhang. “Based on these mice data, we see that microbots can improve antibiotic penetration to kill bacterial pathogens and save more patients’ lives.”

And if the thought of putting algae cells in your lungs makes you feel allergic, researchers say this approach is safe. After the treatment, the body’s immune cells efficiently digest the algae along with any remaining nanoparticles. “Nothing toxic was left,” Wang said.

Work is still in the proof-of-concept stage. The team plans to conduct more basic research to understand exactly how the microbots interact with the immune system. Next steps also include studies to validate and scale up the microrobot therapy before testing it in larger animals, and eventually in humans.

“We are pushing the boundaries further in the area of ​​targeted drug delivery,” Zhang said.

This work is supported by the National Institutes of Health (R01CA200574).

Story source:

Materials Introduction of University of California – San Diego. Original by Lisle Lapius. Note: Content can be modified according to style and length.

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