Hello again – just to remind you that I am posting more over at the Nature Newsblog – do take a look…

The Sci Mix poster session last night was hot, sweaty, and yet again underground with no natural light. I think I’m going to turn into a mole. And what’s this? Free beer at the poster session? Hooray. But there was a catch – you needed tokens, and my humble press registration didn’t include any. Thankfully the look of horror on my face when I realised this prompted the nice man standing behind me in the queue to donate one of his tokens. Thanks very much.

The session had some interesting posters – here’s a brief run down of my faves…. (oh, and watch out for a news story on the news@nature site later on one of them)

“was Boltzmann wrong?” screamed one poster. Well, I couldn’t quite remember what Boltzmann had done apart from have a constant named after him, and the details of that were hazy. Wikipedia tells me it’s the physical constant that relates temperature to energy. So was he wrong? No, it turns out, he just didn’t have to consider nanoscale properties.

Another poster was looking at using titanium dioxide to neutralise astronaut’s waste. And I don’t mean their used teabags. Yuck. But I suppose they can’t all wear nappies all the time.

There was a great poster that detailed how barnacles can be kept off ship’s hulls – but I will let you check back later to read a news piece about that…

This week’s papers from Boston labs

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Tiny magnets provide a picture of RNA delivery

The technology of RNA interference (RNAi)—where small RNA molecules can selectively silence virtually any gene—promises to yield a new type of targeted therapy. But developers of RNAi-based drugs have had trouble both getting the compounds into the right cells and determining whether they actually got there.

Researchers at Massachusetts General Hospital offer a solution: iron nanoparticles, which can simultaneously deliver small RNAs and be detected by magnetic resonance imaging (MRI) within living animals.

Investigator Anna Moore and colleagues coated tiny particles of iron oxide with RNA molecules, plus a short protein that ushered the whole package through the cell membrane. When they injected the particles into tumor-carrying mice, the tumors, which normally appear bright in MRI scans, took on a darker appearance, as they became loaded with the iron particles.

The researchers also attached fluorescent dye molecules to the particles, and under infrared light, the tumors fluoresced brightly, further confirming the uptake of the particles. The particles got into some normal cells, too, but without any apparent toxic effects.

When the researchers removed the tumors for further study, they found that the delivered RNA molecules were effective at silencing a gene important for the survival of the cancer cells, resulting in an increased rate of cell death in the tumors.

The results offer a potential way to track the delivery of RNA drug candidates safely and noninvasively in people, a necessary step toward clinical testing.

The results appear in Nature Medicine. Pat McCaffrey

Nanomaterials grab hydrogen

Before hydrogen-powered cars can become practical, they will need a way of storing and releasing large amounts of hydrogen. A new study by Efthimios Kaxiras of Harvard and colleagues suggests that nanotubes made of boron and studded with titanium atoms may fit the bill.

If you want to store large quantities of hydrogen in a small volume, solid materials that absorb it do a better job than tanks in which it’s compressed or liquefied. But finding a material that can absorb large quantities of hydrogen and then release it in a controlled manner has been a big challenge. Some materials absorb hydrogen only when it’s under high pressure. Others soak up a lot of hydrogen but then don’t let it go, or do so only at high temperatures.

The researchers did detailed atomic-level computer modeling of titanium diboride nanotubes and found that they could solve both problems. The nanotubes should be able to hold and release about 5.5 percent of their own weight in hydrogen without requiring high pressures or temperatures. That’s close to the target of 6 percent that the U.S. government has set for hydrogen storage materials for cars.

Using nanotubes rather than sheets of titanium diboride could be crucial. Not only do nanotubes have a larger surface area, but, the modeling suggests, they also bind to hydrogen more easily than other forms of the same material. The next step would be to test the nanotubes in the lab.

The study appears online in Nano Letters. Mason Inman