New nanoboxes take shape

Chemistry World ^ | 20 August 2009 | Lewis Brindley

[neverdem]

USresearchers have made nano-sized boxes from nickel and tin - marking the first time that patterned 3D structures have been built on the nanoscale. The boxes and fabrication process could have great potential for making interesting nanostructures, for applications ranging from electronics to drug delivery.

'I'm interested in miniaturising the world,' says David Gracias, who led the research at Johns Hopkins University in Baltimore, US. 'We have a lot of nanotechnology techniques that allow us to build very well in 2D - but building in 3D is more difficult.'

The cubes resemble tiny dice around 100nm in size - patterned on each side with the university initials, JHU, in lines as thin as  15nm. 'Patterning in 3D is just as important as building in 3D,' Gracias adds. 'This is because a complex surface allows the construction of circuits or attachment of substrates for biological or optical purposes.' 

Construction of the boxes started with a flat cross-shaped template, made from square 'panels' of nickel joined together by 'hinges' of fragmented tin, all fabricated on a silicon substrate. When heat is applied to the template, the tin grains liquefy and melt together, creating torque that folds and lifts the plates into place, making a cube. 

A flat template of nickel plates and tin hinges will fold up into a cube

© Nano Letters

Using a foldable template means that the panels can be etched in 2D beforehand - either punctured with holes or inscribed with metal such as gold. A downside of the technique is that it requires two treatments of electron-beam lithography - firstly to make the templates, and secondly to etch the sides of the cube away from the silicon surface so they can lift up. This second process is also the source of the heat needed to melt the tin hinges. 

By adjusting the amount of tin in the hinge, the angle of the fold can be changed. The team is hoping to use this to design other interesting shapes like four-sided pyramids or maybe even 12-sided dodecahedrons. 

Illustration of how the nickel plates and tin hinges move and SEM images of nanoboxes etched with the university initials

© Nano Letters

This is fantastic work - it uses a very unconventional approach to make unique 3D structures,' says Stephen Chou, a nanotechnology expert at Princeton University, US. 'I can see many applications of such a creative nanofabrication method in sensors, nanofluidic devices, and others.'

'The idea of folding up 2D structures is not radically new, but it is amazing to see how this strategy can be used to build such complicated structures,' says Chengde Mao, at Purdue University, Indiana, US. The boxes themselves may also prove useful in certain applications; they are metallic and quite stable, so there could be potential in storage, transportation, labelling or confinement, Mao notes. 

 

References

J-H Cho and D H Gracias, Nano Letters, 2009, DOI: 10.1021/nl9022176 

Also of interest

Nano-boxes from DNA origami

06 May 2009

Danish researchers have made a nano-sized box out of DNA that can be opened and closed in response to 'key' molecules

Building nano-scale electronic contacts

11 March 2009

Researchers have welded carbon nanotubes to metal particles to create conducting junctions

DNA shapes up for nanoelectronic devices

17 August 2009

DNA origami forms pre-defined shapes with new lithography technique, potential uses in next generation computer chips

[VisualizeSmallerGovernment]

Wow! A box like that could hold Nancy Pelosi’s brain and still have room left over for Harry Reid’s testicles.

[I see my hands]

Large enough to hold any words of wisdom I have to offer.

[DManA]

Good things come in small packages.

[Tolsti2]

This stuff is like looking at networking and PC’s in the 1980’s. You could tell it was going to take off someday, just took some time. This will be a major revolution in the next 20 years or less. I just hope the USA can stay on top of this one.

[null and void]

She got here first:

Smela box

Elisabeth Smela

[LRoggy]

There was an interesting article last week about a nanotechnology breakthrough on lithium-ion batteries that would make a big improvement in battery life and weight.

If developed it could multiply the run rate 5X.

That would make a big difference in an electric car or computer battery.

[colinhester]

ping for later read.....C

[neverdem]

Thanks for the links.

[Kevmo]

cool

bmflr

[neverdem]

Cardiovascular disease gets personal

Turkeys have been confirmed to have H1N1 (first non-pig/non-human infection)

Flu shot guidelines criticized - Mathematical model suggests that US experts got their priorities wrong.

FReepmail me if you want on or off my health and science ping list.

[Danae]

WAY past too cool...

Nanites here we come.....

[MHGinTN]

What an interesting Lady!

[AFPhys]

Fascinating concept and execution.

I don’t really see a use for this particular item, but the concept is going to have a lot of people with imagination mulling over patents and inventions.