For years, scientists have been fascinated by the tantalizing possibilities of these particles for their potential applications in electronic display devices, sensors and many other devices.
However, realizing these applications requires precise control over the positions and orientation of the particles, something which has until now eluded scientists.
Duke University engineers say they can for the first time control all the degrees of the particle's motion, opening up broad possibilities for nanotechnology and device applications. Their unique technology should make it more likely that Janus particles can be used as the building blocks for a myriad of applications, including such new technologies as electronic paper and self-propelling micromachines.
Typical Janus particles consist of miniscule spherical beads that have one hemisphere coated with a magnetic or metallic material. External magnetic or electric fields can then be used to control the orientation of the particles. However, this coating interferes with optical beams, or traps, another tool scientists use to control positioning.
The breakthrough of Duke engineers was to devise a fabrication strategy to coat the particle with a much smaller fraction of material. This discovery allows these particles to be compatible with optical traps and external magnetic fields, allowing for total control over the particles' positions and orientations."Past experiments have only been able to achieve four degrees of control using a combination of magnetic and optical techniques," said Nathan Jenness, a graduate student who completed his studies this year from Duke's Pratt School of Engineering. He and co-author Randall Erb, also a graduate student, were first authors of a paper appearing online in the journal Advanced Materials. "We have created a novel Janus particle that can be manipulated or constrained with six degrees of freedom."
Using optical traps on dot-Janus particles, researchers controlled three degrees of movement – up and down, left and right, forward and backward, while constraining one degree of rotation - side-to-side tilting. Using magnetic fields, they controlled the remaining two degrees of rotation - forward and backward tilting, and left and right turning.
"The solution was to create a particle with a small cap of cobalt that covers about a quarter of the particle," Erb said. He and Jenness conducted their research in the laboratory of Benjamin Yellen, Duke assistant professor of Mechanical Engineering and Materials Science. "This gave the particle just enough of a magnetic handle to allow it to be manipulated by magnetism without interfering with the optical tweezers."
The researchers said that the fabrication of these unique dot-Janus particles combined with the ability to control their orientation will have important ramifications in the burgeoning field of nanoengineering.
"Being able to more completely control these particles affords us a greater ability to measure the mechanical properties of biomolecules, including DNA," Yellen said. "It may also be possible to control the behavior of cells by manipulating dot-Janus particles attached to cell surfaces. These biological applications, as well as the ability to control the assembly of nanostructures, establish the broad scientific value of these findings."
The research was supported by the National Science Foundation and the Nanoscale Interdisciplinary Research Team. Robert Clark, former Duke dean of engineering and now in the same position at the University of Rochester, was also part of the research team.
Richard Merritt | EurekAlert!
Researchers shoot for success with simulations of laser pulse-material interactions
29.03.2017 | DOE/Oak Ridge National Laboratory
Nanomaterial makes laser light more applicable
28.03.2017 | Christian-Albrechts-Universität zu Kiel
The Institute of Semiconductor Technology and the Institute of Physical and Theoretical Chemistry, both members of the Laboratory for Emerging Nanometrology (LENA), at Technische Universität Braunschweig are partners in a new European research project entitled ChipScope, which aims to develop a completely new and extremely small optical microscope capable of observing the interior of living cells in real time. A consortium of 7 partners from 5 countries will tackle this issue with very ambitious objectives during a four-year research program.
To demonstrate the usefulness of this new scientific tool, at the end of the project the developed chip-sized microscope will be used to observe in real-time...
Astronomers from Bonn and Tautenburg in Thuringia (Germany) used the 100-m radio telescope at Effelsberg to observe several galaxy clusters. At the edges of these large accumulations of dark matter, stellar systems (galaxies), hot gas, and charged particles, they found magnetic fields that are exceptionally ordered over distances of many million light years. This makes them the most extended magnetic fields in the universe known so far.
The results will be published on March 22 in the journal „Astronomy & Astrophysics“.
Galaxy clusters are the largest gravitationally bound structures in the universe. With a typical extent of about 10 million light years, i.e. 100 times the...
Researchers at the Goethe University Frankfurt, together with partners from the University of Tübingen in Germany and Queen Mary University as well as Francis Crick Institute from London (UK) have developed a novel technology to decipher the secret ubiquitin code.
Ubiquitin is a small protein that can be linked to other cellular proteins, thereby controlling and modulating their functions. The attachment occurs in many...
In the eternal search for next generation high-efficiency solar cells and LEDs, scientists at Los Alamos National Laboratory and their partners are creating...
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are less stable. Now researchers at the Technical University of Munich (TUM) have, for the first time ever, produced a composite material combining silicon nanosheets and a polymer that is both UV-resistant and easy to process. This brings the scientists a significant step closer to industrial applications like flexible displays and photosensors.
Silicon nanosheets are thin, two-dimensional layers with exceptional optoelectronic properties very similar to those of graphene. Albeit, the nanosheets are...
20.03.2017 | Event News
14.03.2017 | Event News
07.03.2017 | Event News
29.03.2017 | Materials Sciences
29.03.2017 | Physics and Astronomy
29.03.2017 | Earth Sciences