Cyborgs against pneumonia
Tiny floating Robots Treat deadly pneumonia in Mice
Julia Tisler, ERR
An image of a micro robot for fighting pneumonia, consisting of an algae cell (green) coated with nanoparticles of a biodegradable polymer (brown). The nanoparticles contain antibiotics and are covered with neutrophil cell membranes. Authors: Fangyu Zhang and Zhengxing Li.
Nanoengineers from the University of California, San Diego have developed microscopic robots that can float in the lungs, deliver medicines and be used to treat life-threatening cases of bacterial pneumonia.
In mice, the micro-robots safely destroyed pneumonia-causing bacteria in the lungs and resulted in 100% survival. Mice from the control group died within three days after infection.
Microrobots are made of algae cells, the surface of which is covered with antibiotic-filled nanoparticles. Algae provide movement, which allows the micro-robots to swim and deliver antibiotics to bacterial accumulations in the lungs. Nanoparticles containing antibiotics consist of tiny biodegradable polymer spheres. They are covered with neutrophil cell membranes, which are a type of white blood cells. The peculiarity of these cell membranes is that they absorb and neutralize inflammatory molecules produced by bacteria and the body's immune system.
The work is a joint effort of the laboratories of professors of nanoengineering Joseph Wang and Liangfang Zhang from the Jacobs School of Engineering at the University of California, San Diego. Wang is a world leader in research in micro- and nanorobotics, and Zhang is a leader in the development of cell—mimicking nanoparticles for the treatment of infections and diseases. Together they pioneered the development of tiny robots for drug delivery. Micro robots can already be safely used on live animals to treat bacterial infections in the stomach and blood. The treatment of bacterial infections of the lungs is the last direction of their activity.
"Our goal is targeted drug delivery to more complex parts of the body, such as the lungs. And we want to do it in a safe, simple, biocompatible and long—lasting way," Zhang said.
The team used micro-robots to treat mice with an acute and potentially fatal form of pneumonia caused by Pseudomonas aeruginosa bacteria. This form of pneumonia usually affects patients who are on artificial ventilation in the intensive care unit. The researchers injected micro-robots into the lungs of mice through a tube inserted into the trachea. The infections completely disappeared after a week. All mice treated with micro-robots survived for 30 days, and mice that did not receive treatment died within three days.
Treatment with micro-robots also proved to be more effective than intravenous administration of antibiotics into the bloodstream. In addition, with intravenous administration, a dose of antibiotics is required to achieve the same effect, which is 3000 times higher than the amount used in micro robots.
The new approach is effective because it puts the medicine exactly where it is needed, rather than scattering it all over the body. "These results show how targeted drug delivery combined with active movement of microalgae increases therapeutic efficacy," Wang said.
And if the idea of putting algae cells in your lungs makes you squeamish, then the researchers answer that this approach is safe. After treatment, the body's immune cells efficiently recycle algae along with any remaining nanoparticles. "There's nothing toxic left," Wang said.
The work is still in the proof-of-concept stage. The team plans to conduct additional fundamental research to understand exactly how micro-robots interact with the immune system.
The results were published on September 22 in Nature Materials (Zhang et al., Nanoparticle-modified microrobots for in vivo antibiotic delivery to treat acute bacterial pneumonia).
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