Researchers from the University of California have developed acid-fueled micro-machines capable of traveling and delivering cargo directly inside a living creature. It's a breakthrough that's expected to significantly advance the field of medical nano-robotics.
Scientists have developed drug-delivering micro-machines before, but these systems were only tested under in vitro conditions (i.e., cell cultures outside the body). But in this latest breakthrough, Wei Gao and colleagues have shown that artificial micromotors can travel inside a live mouse, deliver its cargo, and produce no toxic effects.
This is definitely an important proof-of-concept. Nanotechnology has the potential to reshape the way medicine is done. In the future, scaled-up versions of this rudimentary micro-machine could deliver important medicines to previously inaccessible parts of the body (e.g., to treat peptic ulcers and other illnesses), fight infectious diseases, or even perform complex tasks like direct cellular manipulation and repair.
The University of California researchers say the breakthrough is an important step forward in the field of synthetic nano/micromotors, one that will "promote interdisciplinary collaborations toward expanding the horizon of [human-made] machines in medicine."
To make it happen, the researchers constructed polymer tubes coated with zinc. The miniscule machines were a mere 20 micrometers long, which is about the width of a strand of human hair. Once implanted in the gut of a live mouse, the zinc reacted to the acid in the stomach by producing bubbles of hydrogen, which propelled the nanobots into the stomach lining. Once attached, they began to dissolve, thereby delivering their nanoparticle contents within the stomach tissue.
"Such an active motor-based delivery strategy offers dramatic improvement in the efficiency compared to common passive diffusion of orally administrated cargoes," write the authors of the study, which now appears in the journal ACS Nano. "While additional in vivo [in the body] characterizations are warranted to further evaluate the performance and functionalities of various [human-made] micromotors in living organisms, this study represents the very first step toward such a goal."
Images: Wei Gao et al./ACS Nano.