Nanorobots that are introduced into the body to eradicate tumor cells or clean out clogged arteries are not just science fiction; they are a realistic vision of the technological possibilities of the not-so-distant future.
Efficient nanomotors will be needed to drive these nanomachines. A team of scientists from University of California, San Diego (USA) and Arizona State University (Tempe, USA) has now developed nanorods that swim extremely fast.
“These nanorods travel about 75 times their own length in one second,” report Joseph Wang and his co-workers in the journal Angewandte Chemie. “We are approaching the speed of the most efficient biological nanomotors, including flagellated bacteria.”
The first simple applications for nanomotors could include rapid transportation of pharmaceutical agents to specific target areas, or the passage of specimen molecules through the tiny channels of diagnostic systems on a microchip.
However, forward motion through a liquid is not as trivial as one would like to think. One method for the construction of nanomotors that can achieve this is the fuel-driven catalytic nanowire. These are tiny nanoscopic rods whose ends are made of two different metals. Unlike macroscopic motors, they do not have a fuel tank; instead they move through a medium that contains the fuel they need.
The “classic” example of such a system is a gold–platinum nanotube that can travel at speeds of 10 to 20 µm per second with hydrogen peroxide as its fuel. Wang and his team have now dramatically accelerated these nanorod motors: they have achieved speeds of over 150 µm per second by replacing the gold portion with an alloy of silver and gold. How does the nanomotor work? The platinum segment catalyzes the splitting of hydrogen peroxide (H2O2) into oxygen (O2) and protons (H+). It absorbs the excess electrons.
These are transferred to the silver/gold segment, where they speed up the reduction reaction of H2O2 and protons to make water. The release of oxygen and water produces a small current, which drives the nanorod through the fluid, platinum side first. “The silver/gold alloy causes the electrons to be transferred more quickly,” explains Wang. “This increases the fuel decomposition rate and the nanorod is accelerated faster.” The speed of the nanorods can be tailored by changing the proportion of silver in the alloy. “Fuel additives or variations of the platinum segment will make these rods even faster,” predicts Wang.
Author: Joseph Wang, University of California, San Diego (USA), http://nanoengineering.ucsd.edu/~joewang/
Title: Ultrafast Catalytic Alloy Nanomotors
Angewandte Chemie International Edition, doi: 10.1002/anie.200803841
Repairing damaged hearts with self-healing heart cells
22.08.2017 | National University Health System
Biochemical 'fingerprints' reveal diabetes progression
22.08.2017 | Umea University
Whether you call it effervescent, fizzy, or sparkling, carbonated water is making a comeback as a beverage. Aside from quenching thirst, researchers at the University of Illinois at Urbana-Champaign have discovered a new use for these "bubbly" concoctions that will have major impact on the manufacturer of the world's thinnest, flattest, and one most useful materials -- graphene.
As graphene's popularity grows as an advanced "wonder" material, the speed and quality at which it can be manufactured will be paramount. With that in mind,...
Physicists at the University of Bonn have managed to create optical hollows and more complex patterns into which the light of a Bose-Einstein condensate flows. The creation of such highly low-loss structures for light is a prerequisite for complex light circuits, such as for quantum information processing for a new generation of computers. The researchers are now presenting their results in the journal Nature Photonics.
Light particles (photons) occur as tiny, indivisible portions. Many thousands of these light portions can be merged to form a single super-photon if they are...
For the first time, scientists have shown that circular RNA is linked to brain function. When a RNA molecule called Cdr1as was deleted from the genome of mice, the animals had problems filtering out unnecessary information – like patients suffering from neuropsychiatric disorders.
While hundreds of circular RNAs (circRNAs) are abundant in mammalian brains, one big question has remained unanswered: What are they actually good for? In the...
An experimental small satellite has successfully collected and delivered data on a key measurement for predicting changes in Earth's climate.
The Radiometer Assessment using Vertically Aligned Nanotubes (RAVAN) CubeSat was launched into low-Earth orbit on Nov. 11, 2016, in order to test new...
A study led by scientists of the Max Planck Institute for the Structure and Dynamics of Matter (MPSD) at the Center for Free-Electron Laser Science in Hamburg presents evidence of the coexistence of superconductivity and “charge-density-waves” in compounds of the poorly-studied family of bismuthates. This observation opens up new perspectives for a deeper understanding of the phenomenon of high-temperature superconductivity, a topic which is at the core of condensed matter research since more than 30 years. The paper by Nicoletti et al has been published in the PNAS.
Since the beginning of the 20th century, superconductivity had been observed in some metals at temperatures only a few degrees above the absolute zero (minus...
16.08.2017 | Event News
04.08.2017 | Event News
26.07.2017 | Event News
22.08.2017 | Health and Medicine
22.08.2017 | Materials Sciences
22.08.2017 | Life Sciences