Post Tagged with: "NanoLett"


Stephen J. Ebbens

Jonathan Howse

The current state of the art in nanopropulsion devices was recently reviewed by Ebbens and Howse in an article last Friday.[SoftMatter] A short summary of the nano- systems is presented below with video action shots when I could find them.

The Whitesides

Catalyst: Pt
Fuel: H2O2
Propulsion: Bubble propulsion
Terrain: Aqueous meniscus
Max Speed: 2 cm/s
Mitch’s Name: The Karl Benz (since it was the first)
Article: Autonomous Movement and Self-Assembly

The Sen-Mallouk-Crespi

Catalyst: Pt
Fuel: H2O2
Propulsion: Self electrophoresis/Interfacial tension
Terrain: Settled near boundary in aqueous solution
Max Speed: 6.6 um/s
Mitch’s Names: The Ford Mustang of nanopropulsion. (It is a hot rod, get it?)
Article: Catalytic Nanomotors: Autonomous Movement of Striped Nanorods

The Jones-Golestanian

Catalyst: Pt
Fuel: H2O2
Propulsion: Pure self diffusiophoresis
Terrain: Free aqueous solution
Max Speed: 3um/s
Mitch’s Name: The Volkswagen Beetle
Article: Self-Motile Colloidal Particles: From Directed Propulsion to Random Walk

The Mano-Heller

Catalyst: Glucose oxidase and Biliruben oxidase
Fuel: Glucose
Propulsion: Self electrophoresis
Terrain: Aqueous meniscus
Max Speed: 1 cm/s
Mitch’s Name: The Komatsu Truck (because it is huge)
Article: Bioelectrochemical Propulsion

The Feringa

Catalyst: Synthetic catalse
Fuel: H2O2
Propulsion: Bubble/interfacial
Terrain: Acetonitrile solution
Max Speed: 35 um/s
Mitch’s Name: The F150 (has some exhaust issues)
Article: Catalytic molecular motors: fuelling autonomous movement by a surface bound synthetic manganese catalase

The Sen-Mallouk

Catalyst: Pt (CNT) (+cathodic reactions at Au)
Fuel: H2O2/N2H4
Propulsion: Self electrophoresis
Terrain: Settled near boundary in aqueous solution
Max Speed: 200 um/s
Mitch’s Names: The Ford Mustang GT (has more kick than the regular version)
Article: Bipolar Electrochemical Mechanism for the Propulsion of Catalytic Nanomotors in Hydrogen Peroxide Solutions

The Feringa v2

Catalyst: Glucose oxidase and catalse
Fuel: Glucose
Propulsion: Local oxygen bubble formation
Terrain: Free aqueous buffer solution
Max Speed: 0.2–0.8 um/s
Mitch’s Name: The Chevrolet Nova (more hot rod action)
Article: Autonomous propulsion of carbon nanotubes powered by a multienzyme ensemble

The Gibbs-Zhao

Catalyst: Pt
Fuel: H2O2
Propulsion: Bubble release mechanism
Terrain: Aqueous solution
Max Speed: 6 um/s
Mitch’s Name: The Rover
Article: Autonomously motile catalytic nanomotors by bubble propulsion

The Bibette

Engine: External magnetic field
Propulsion: Flagella
Terrain: Aqueous solution
Max Speed: unknown
Mitch’s name: The BMW Mini E (because there is no such thing as a magnetic car)
Article: Microscopic artificial swimmers

The Sagués

Engine: External magnetic field
Propulsion: Doublet rotation coupling with boundary interactions
Terrain: Settled near boundary in aqueous solution
Max Speed: 3.2 um/s
Mitch’s Name: The Smart ED
Article: Magnetically Actuated Colloidal Microswimmers

The Fischer

Engine: External magnetic field
Propulsion: Propeller drive
Terrain: Aqueous solution
Max Speed: 40 um/s
Mitch’s Name:
Article: Controlled Propulsion of Artificial Magnetic Nanostructured Propellers

The Najafi-Golestanian

Engine: Conformation changes in linking units
Propulsion: Time irreversible translations
Terrain: Free solution
Max Speed: ?
Mitch’s Name: The Eternal Concept Car
Article: Propulsion at low Reynolds number

Some devices that were not included by the authors of the review article, but should definitely be included in any list like this are below:

The Gracias

Engine: External magnetic field
Propulsion: Brute Force
Terrain: Aqueous solution
Max Speed: ?
Mitch’s Name: The Truck Cranes
Article: Tetherless thermobiochemically actuated microgrippers

Tetherless Microgrippers Grabs Tissue SampleWatch today’s top amazing videos here

The Nelson

Engine: External electromagnetic fields
Propulsion: Flagella
Terrain: ?
Max Speed: 18 um/s
Mitch’s Name: The Tesla Roadster (simply awesome)
Article: Characterizing the Swimming Properties of Artificial Bacterial Flagella

Artificial SpermWatch more funny videos here

Link to Review Article: In pursuit of propulsion at the nanoscale


By January 16, 2010 5 comments materials chemistry

Metallic Flagella

The control of metallic flagella with magnetic fields is the subject of a recent paper by Li Zhang and Bradley Nelson.[NanoLett] The synthetic approach is a top-down process, and an image of a pre-released flagellum is shown below.

metal flagellum

Although typical bacteria like E. Coli are 1-2 μm long, this system is still a fascinatingly model of the motion of objects at low Reynolds numbers. The head of the artificial bacterium is composed of thin films of chromium, nickel, and gold. While the helical body is a composite of layers of indium gallium arsenide, gallium arsenide, and chromium. Motion is controlled by using three orthogonal electromagnetic coil pairs at 1-2 mT and a frequency of 5-35 Hz. A video of two of their flagella in action is shown below.

A couple of other videos showing the ability of the authors to steer the flagella are provided here: 1 flagellum, 3 flagella.

This system is a fascinating example of precise control of small devices that do not require outside chemical or photo sources. These systems have enormous promise and will likely comprise the type of motion the first nanorobots will utilize. One should couple this system to Gracias’ current generation of microgrippers for even more awesomeness.

Link to the article is here: Characterizing the Swimming Properties of Artificial Bacterial Flagella


By September 6, 2009 4 comments materials chemistry

Linear-Motor from Carbon Nanotubes

A recent paper this week by Somada et al. regarding making a linear-motor from carbon nanotubes piqued my interest.[NanoLett] The general design idea is to encapsulate a piece of carbon nanotube material within a larger carbon nanotube. If done correctly you can end up with a configuration as shown below.

Reprinted with permission from American Chemical Society: Nano Letters (Nov. 2008).

The cargo, in yellow, transverses the carbon nanotube and rests in either position A or position B. An abridged summary of their observations is as follows: 1) From observing the system for 170 s the cargo traveled back-and-forth seven times; 2) The cargo was never filmed in between positions A and B, indicating the movement was less than the frame rate (0.5 s). From this information I can construct a likely energy landscape for this system.

Mitch’s hypothetical potential energy map for the linear-motor.

The diagram replicates the observation that the cargo at room temperature will be trapped at either position A or B. It also explains why it’s never seen between A or B, as there is no energy minimum for it to rest in. Lets assume every ~20 s there is randomly enough thermal energy to kick the system over the barrier, and that this accessible energy exists for less than 0.5 s. Then you would expect the cargo to be able to move either to A or B, and to do it faster than the shutter speed.

This is an interesting system for analysis, but it’s not a motor. Or conversely, it is as much a motor as ethane is a useful rotor. Just because thermal energy provides the means for things to happen it doesn’t mean it generates usable work. There is no way to construct a usable motor or any device from this system, but it’s a first step in that direction. I suspect if the authors raised the temperature they would see the cargo undergoes random walk motion. Thermal energy yields a random linear-motor.

Link to article: A Molecular Linear Motor Consisting of Carbon Nanotubes

Update 1: Tim Reid also covered it at Nature Chemistry — Nanotube motors: Sliding and spinning


By November 30, 2008 0 comments materials chemistry