Just in time for the World Cup final, researchers have succeeded in building the first ‘buckyballs’  made entirely from boron atoms. Unlike true, carbon-based buckyballs, the boron molecules are not shaped exactly like footballs.  But this novel form of boron might lead to new nanomaterials and could find uses in hydrogen storage.

Robert Curl, Harold Kroto and Richard Smalley found the first buckyball — or buckminsterfullerene — in 1985. The hollow cage, made of 60 carbon atoms arranged in pentagons and hexagons like a football, got its name from the US architect and engineer Richard Buckminster Fuller, who used the same shapes in designing his domes. The discovery opened the flood gates for creating more carbon structures with impressive qualities, such as carbon nanotubes and the single-atom-thick graphene. Since then, materials scientists have also searched for buckyball-like structures made of other elements.

Clusters of 40 boron atoms form a hollow cage similar to the carbon buckyball{credit}Wang lab/Brown University{/credit}

In 2007, Boris Yakobson, a materials scientist at Rice University in Houston, Texas, theorized that a cage made of 80 boron atoms should be stable. Another study published just last week predicts a stable structure with 36 boron atoms.

Publishing today in Nature Chemistry, a team led by Lai-Sheng Wang, a chemist at Brown University in Providence, Rhode Island, has become the first to see such a beast — although its structure is slightly different from that predicted. The researchers call their 40-atom molecule borospherene. It is arranged in hexagons, heptagons and triangles.

“We predicted the possibility of B80 fullerene, and now, seven years after, it is remarkable to see experimental evidence,” says Yakobson. “Especially as it is not what any of the theoretical calculations predicted.”

Wang’s team found the structure while looking for analogues of graphene made of boron. They found that clusters of 40 boron atoms seemed to be unusually stable, but they didn’t know what form these clusters were taking. Further calculations and experiments revealed that they had made two stable structures — one an almost flat molecule, the other a hollow, ball-like structure made of tesselated shapes, similar to the carbon buckyball.

In addition to having a less elegant shape, the borosphene balls form a different type of internal bond from their carbon counterparts. This makes them difficult to use as isolated building blocks as they have a tendency interact with each other, but this reactivity may make boron buckyballs good for connecting in chains. It also makes the balls capable of bonding with hydrogen, which the team says could make them useful in hydrogen storage.

Boron is not the first element after carbon to get buckyballed, but the result may be the closest analogue to the carbon variety. Scientists have formed buckyball-like structures out of uranium-based and silicon-based compounds, mutli-walled boron nitride and molybdenum disulphide structures and smaller single-element cages of gold, tin and lead. But only boron seems to match the large hollow cage and  symmetry of the original carbon buckyball, says Yakobson.

Atomic resolution, scanning transmission electron microscope image of part of a nanosheet of shear exfoliated graphene. Credit: CRANN/SuperSTEM

Don’t try this at home. No really, don’t: it almost certainly won’t work and you won’t be able to use your kitchen blender for food afterwards. But buried in the supplementary information of a research paper published today is a domestic recipe for producing large quantities of clean flakes of graphene.

The carbon sheets are the world’s thinnest, strongest material;  electrically conductive and flexible; and tipped to transform everything from touchscreen displays to water treatment. Many researchers — including Jonathan Coleman at Trinity College Dublin — have been chasing ways to make large amounts of good-quality graphene flakes.

In Nature Materials, a team led by Coleman (and funded by the UK-based firm Thomas Swan) describe how they took a high-power (400-watt) kitchen blender and added half a litre of water, 10–25 millilitres of detergent and 20–50 grams of graphite powder (found in pencil leads). They turned the machine on for 10–30 minutes. The result, the team reports: a large number of micrometre-sized flakes of graphene, suspended in the water.

Coleman adds, hastily, that the recipe involves a delicate balance of surfactant and graphite, which he has not yet disclosed (this barrier dissuaded me from trying it out; he is preparing a detailed kitchen recipe for later publication). And in his laboratory, centrifuges, electron microscopes and spectrometers were also used to separate out the graphene and test the outcome. In fact, the kitchen-blender recipe was added late in the study as a bit of a gimmick — the main work was done first with an industrial blender (pictured).

Five litres of suspended graphene (in an industrial blender). Credit: CRANN.

Still, he says, the example shows just how simple his new method is for making graphene in industrial quantities. Thomas Swan has scaled the (patented) process up into a pilot plant and, says commercial director Andy Goodwin, hopes to be making a kilogram of graphene a day by the end of this year, sold as a dried powder and as a liquid dispersion from which it may be sprayed onto other materials.

“It is a significant step forward towards cheap and scalable mass production,” says Andrea Ferrari, an expert on graphene at the University of Cambridge, UK. “The material is of a quality close to the best in the literature, but with production rates apparently hundreds of times higher.”

The quality of the flakes is not as high as that of the ones the winners of the 2010 Nobel Prize in Chemistry, Andre Geim and Kostya Novoselov from Manchester University, famously isolated using Scotch Tape to peel off single sheets from graphite. Nor are they as large as the metre-scale graphene sheets that firms today grow atom by atom from a vapour. But outside of high-end electronics applications, smaller flakes suffice — the real question is how to make lots of them.

Although hundreds of tons of graphene are already being produced each year — and you can easily buy some online — their quality is variable. Many of the flakes in store are full of defects or smothered with chemicals, affecting their conductivity and other properties, and are tens or hundreds of layers thick. “Most of the companies are selling stuff that I wouldn’t even call graphene,” says Coleman.

The blender technique produces small flakes some four or five layers thick on average, but apparently without defects — meaning high electrical conductivity. Coleman thinks the blender induces shear forces in the liquid sufficient to prise off sheets of carbon atoms from the graphite chunks (“as if sliding cards from a deck”, he explains).

Kitchen blenders aren’t the only way to produce reasonably high-quality flakes of graphene. Ferrari still thinks that using ultrasound to rip graphite apart could give better materials in some cases. And Xinliang Feng, from the Max Planck Institute for Polymer Research in Mainz, Germany, says that his recent publication, in the Journal of the American Chemical Society, reports a way to produce higher-quality, fewer-layer graphene at higher rates by electrochemical means. (Coleman points out that Thomas Swan have taken the technique far beyond what is reported in the paper.)

As for applications, “the graphene market isn’t one size fits all”, says Coleman, but the researchers report testing it as the electrode materials in solar cells and batteries. He suggests that the flakes could also be added as a filler into plastic drinks bottles — where their added strength reduces the amount of plastic needed, and their ability to block the passage of gas molecules such as oxygen and carbon dioxide maintains the drink’s shelf life.

In another application altogether, a small amount added to rubber produces a band whose conductivity changes as it stretches — in other words, a sensitive strain sensor. Thomas Swan’s commercial manager, Andy Goodwin, mentions flexible, low-cost electronic displays; graphene flakes have also been suggested for use in desalination plants and even condoms.

In each case, it has yet to be proven that the carbon flakes really outperform other options — but the new discoveries for mass-scale production mean that we should soon find out. At the moment, an array of firms is competing for different market niches, but Coleman predicts a thinning-out as a few production techniques dominate. “There are many companies making and selling graphene now: there will be many fewer in five years’ time,” he says.

A self-assembling nanoparticle designed to target tumour cells as a virus would was unveiled today.

Viruses are extremely effective at targeting cells and delivering proteins into them. Mimicking a virus should therefore be a very useful way to deliver drugs to cancerous cells.

This morning at the American Chemical Society’s annual fall meeting in Philadelphia, Pennsylvania, Yuhong Chen presented data on a fully synthetic self-assembling virus-like nanoparticle. These particles fuse with cells “like real viruses”, notes Chen’s abstract. Chen, a chemist at the National Cancer Institute in Frederick, Maryland, gave a presentation on these particles before I arrived in the city. But earlier this week, his fellow researcher Nadya Tarasova explained some of the thinking behind them.

Tarasova, head of the Synthetic Biologics Core at the National Cancer Institute, notes that viruses are perfect delivery systems because they self-assemble and enter cells using receptors on cell surfaces.

To mimic a virus, the team used amino acids to build a molecule that resembles a known protein that spans cell membranes. In a paper in the Proceedings of the National Academy of Sciences (PNAS), the team previously described how these proteins self-assemble into spherical nanoparticles in solution. Now the team has gone further, showing that these nanoparticles can fuse with cells through receptors. By incorporating compounds into their nanoparticles that normally bind prostate tumour cells, their virus-mimic selectively targets these cells.

These nanoparticles were shown in the PNAS paper to hamper tumour growth in vivo. But the real trick is that they can be used to encapsulate drugs, meaning that a synthetic virus-like particle could be created to target cancer cells and then deliver a chemotherapy payload precisely to the tumour.

Creating virus-like nanoparticles using synthetic chemistry allows a huge degree of control over the particles’ properties such as their size and shape, says Tarasova. The team’s particles assemble with remarkable precision, and the researchers are now working on getting the nanoparticles into an animal model.

“In several respects, we outdid nature,” says Tarasova.