From Knovel.com: Evoking Isaac Asimov, scientists unveil hydrogen-propelled microrockets capable of navigating the stomach
Scientists at the University of California, San Diego, are developing miniature machines capable of entering and moving throughout the bloodstream – without fuel.
Researchers from the California university said that they had designed "microrockets" that could easily travel in acidic environments without the need for a fuel source. They noted that physicians and other medical professionals could one day use such microrockets to more thoroughly study a patient's digestive tract, among other potential uses.
The breakthrough technology does not need a fuel supply to operate, Popular Science reports. It moves, rather, by manipulating hydrogen bubbles produced by a chemical reaction. The microrockets are made from zinc, and they react naturally with acidic solutions, which are naturally present in the stomach.
The microrockets have a lifespan ranging between 10 seconds and two minutes, according to the scientists. They affirmed that their lifespan varied depending on the rate of zinc dissolution. They are tiny tubes approximately 10 micrometers in length, but their diameters range from two to five micrometers. The researchers affirmed they crafted the tubes out of polymer polyaniline, inserting a thin layer of zinc in their inside surface.
While the microrockets currently navigate throughout acidic environments autonomously, the team of scientists contended it is possible to control their trajectory. What's more, they said they could program them to pick up and drop off "cargo" through the use of magnets.
The tiny vessels react readily in the hyper acidic environment of the stomach, creating hydrogen bubbles that form inside the rocket. Eventually, the hydrogen bubbles reach a critical mass, propelling the microrockets at speeds surpassing 100 body lengths per second, roughly equivalent to 1,050 micrometers per second.
PhysOrg reports that the scientists, Wei Gao, Aysegul Uygun and Joseph Wang, noted the microrockets could have far-reaching applications in both biomedical and industrial engineering research. They said that they envision physicians and engineers utilizing the devices in the future, molding them to perform specific tasks.
"This is the first reported example of chemically-powered microrockets that can be self-propelled without an external fuel," Wang asserted. "Such acid-powered microrockets could greatly expand the scope of applications of nano and microscale motors toward new extreme environments, and could thus lead to diverse new biomedical or industrial applications ranging from targeted drug delivery or nanoimaging to the monitoring of industrial processes."
They published their findings, "Hydrogen-Bubble-Propelled Zinc-Based Microrockets in Strongly Acidic Media," in the journal of the American Chemical Society.