David Kirkpatrick

June 4, 2009

Photon driven nanomotor

Fair warning to all readers, a major press release dump is coming. Mostly nanotechnology news.

First up is research on a molecular nanomotor driven by light.

The release:

New, light-driven nanomotor is simpler, more promising, scientists say

GAINESVILLE, Fla. — Sunflowers track the sun as it moves from east to west. But people usually have to convert sunlight into electricity or heat to put its power to use.

Now, a team of University of Florida chemists is the latest to report a new mechanism to transform light straight into motion – albeit at a very, very, very tiny scale.

In a paper expected to appear soon in the online edition of the journal Nano Letters, the UF team reports building a new type of “molecular nanomotor” driven only by photons, or particles of light. While it is not the first photon-driven nanomotor, the almost infinitesimal device is the first built entirely with a single molecule of DNA — giving it a simplicity that increases its potential for development, manufacture and real-world applications in areas ranging from medicine to manufacturing, the scientists say.

“It is easy to assemble, has fewer parts and theoretically should be more efficient,” said Huaizhi Kang, a doctoral student in chemistry at UF and the first author of the paper.

The scale of the nanomotor is almost vanishingly small.

In its clasped, or closed, form, the nanomotor measures 2 to 5 nanometers — 2 to 5 billionths of a meter. In its unclasped form, it extends as long as 10 to 12 nanometers. Although the scientists say their calculations show it uses considerably more of the energy in light than traditional solar cells, the amount of force it exerts is proportional to its small size.

But that won’t necessarily limit its potential.

In coming years, the nanomotor could become a component of microscopic devices that repair individual cells or fight viruses or bacteria. Although in the conceptual stage, those devices, like much larger ones, will require a power source to function. Because it is made of DNA, the nanomotor is biocompatible. Unlike traditional energy systems, the nanomotor also produces no waste when it converts light energy into motion.

“Preparation of DNA molecules is relatively easy and reproducible, and the material is very safe,” said Yan Chen, a UF chemistry doctoral student and one of the authors of the paper.

Applications in the larger world are more distant. Powering a vehicle, running an assembly line or otherwise replacing traditional electricity or fossil fuels would require untold trillions of nanomotors, all working together in tandem — a difficult challenge by any measure.

“The major difficulty lies ahead,” said Weihong Tan, a UF professor of chemistry and physiology, author of the paper and the leader of the research group reporting the findings. “That is how to collect the molecular level force into a coherent accumulated force that can do real work when the motor absorbs sunlight.”

Tan added that the group has already begun working on the problem.

“Some prototype DNA nanostructures incorporating single photo-switchable motors are in the making which will synchronize molecular motions to accumulate forces,” he said.

To make the nanomotor, the researchers combined a DNA molecule they created in the lab with azobenzene, a chemical compound that responds to light. A high-energy photon prompts one response; lower energy another.

To demonstrate the movement, the researchers attached a fluorophore, or light-emitter, to one end of the nanomotor and a quencher, which can quench the emitting light, to the other end. Their instruments recorded emitted light intensity that corresponded to the motor movement.

“Radiation does cause things to move from the spinning of radiometer wheels to the turning of sunflowers and other plants toward the sun,” said Richard Zare, distinguished professor and chairman of chemistry at Stanford University. “What Professor Tan and co-workers have done is to create a clever light-actuated nanomotor involving a single DNA molecule. I believe it is the first of its type.”

 

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The National Institutes of Health and the National Science Foundation funded the research. The other coauthors of this paper are Haipeng Liu, Joseph A. Phillips, Zehui Cao, Youngmi Kim, Zunyi Yang and Jianwei Li.

April 16, 2008

World’s first thermal nanomotor

Filed under: Science, Technology — Tags: , , , , — David Kirkpatrick @ 2:35 pm

The release:

Researchers create the first thermal nanomotor in the world

The motor functions as a nanotransporter by moving and rotating cargo from one end of the carbon nanotube to the other

This release is available in Spanish.

Researchers from the UAB Research Park have created the first nanomotor that is propelled by changes in temperature. A carbon nanotube is capable of transporting cargo and rotating like a conventional motor, but is a million times smaller than the head of a needle. This research opens the door to the creation of new nanometric devices designed to carry out mechanical tasks and which could be applied to the fields of biomedicine or new materials.

The “nanotransporter” consists of a carbon nanotube – a cylindrical molecule formed by carbon atoms – covered with a shorter concentric nanotube which can move back and forth or act as a rotor. A metal cargo can be added to the shorter mobile tube, which could then transport this cargo from one end to the other of the longer nanotube or rotate around its axis.

Researchers are able to control these movements by applying different temperatures at the two ends of the long nanotube. The shorter tube thus moves from the warmer to the colder area and is similar to how air moves around a heater. This is the first time a nanoscale motor is created that can use changes in temperature to generate and control movements.

The movements along the longer tube can be controlled with a precision of less than the diameter of an atom. This ability to control objects at nanometre scale can be extremely useful for future applications in nanotechnology, e.g. in designing nanoelectromechanical systems with great technological potential in the fields in biomedicine and new materials.

 

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The research has been published in the online journal Science Express (www.sciencexpress.org) and was directed by Adrian Bachtold, researcher at CIN2 (Nanoscience and Nanotechnology Research Centre, CSIC-ICN) and at CNM (National Microelectronics Centre, CSIC), and by Eduardo Hernández at ICMAB (Institute of Material Science, CSIC), all of which form part of the UAB Research Park. Research members included Riccardo Rurali from the UAB Department of Electronic Engineering, and Amelia Barreiro and Joel Moser from CIN2 (CSIC-ICN), with the collaboration of researchers from the University of Vienna, Austria and from EPFL in Lausanne, Switzerland.

The Catalan Institute of Nanotechnology is a private foundation publicly funded by the Catalan Government and Universitat Autònoma de Barcelona. The Nanoscience and Nanotechnology Research Centre is run jointly by the Spanish National Research Council and the Catalan Institute of Nanotechnology. The National Microelectronics Centre (CNM) and the Institute of Material Sciences (ICMAB) both belong to the Spanish National Research Council. The UAB Research Park – a joint alliance between UAB, CSIC and IRTA (Institute for Food and Agricultural Research and Technology) – is formed by a group of research centres and consortiums located at the Bellaterra campus of Universitat Autònoma de Barcelona.

(Hat tip: KurzweilAI.net)