Now one of the problems with creating nanotech is, of course, it’s invisibility to the human eye, or in fact, anything but extremely high powered equipment. So to verify that they had created a surface with nano-size bubbles, the samples were taken to the National Synchrotron Light Source for x-ray measurements. The x-rays diffracted (bounced) off the surface, which was captured in images that showed the cavities to be filled mostly with air. The bubbles were only about 10 nanometers in size and rather surprisingly had flat tops (most bubbles have convex – upward curving – tops). This would significantly increase the slippage along the tops of the bubbles. They also discovered that water barely penetrated the cavities, perhaps only 15-30 molecules deep, which meant the bubbles would be very stable.

The end result was an extremely water-repellant surface, for which the team coined a word – superhydrophobicity (try that in Scrabble sometime). This has a wide variety of potential (and important) applications. As a member of the team put it…

“Our results explain how these nanocavities trap tiny bubbles which render the surface extremely water repellent,” said Brookhaven physicist and lead author Antonio Checco. The research could lead to a new class of non-stick materials for a range of applications, including improved-efficiency power plants, speedier boats, and surfaces that are resistant to contamination by germs.

Non-stick surfaces are important to many areas of technology, from drag reduction to anti-icing agents. These surfaces are usually created by applying coatings, such as Teflon, to smooth surfaces. But recently — taking the lead from observations in nature, notably the lotus leaf and some varieties of insects — scientists have realized that a bit of texture can help. By incorporating topographical features on surfaces, they’ve created extremely water repellant materials.

[Source: Brookhaven National Laboratories]

As is often the case with nanotechnology, this work is a long way from commercial application. In some respects, this was a proof of concept more than a technical demonstration. There is still much work to be done with other materials (like the surfactant) as well as addressing many questions about manufacturing in quantity.

The first announcement sort of fits the battle metaphor. It’s characterized as ‘zapping nanobubbles.’ …Researchers at Rice University (Houston, USA) have developed a technique for treating cancer cells – one at a time if appropriate – by using gold nanoparticles. The nanoparticles are targeted for a specific type of cancer, where they attach to individual cells. Then a laser device, set to a specific frequency, causes the gold nanoparticles to heat causing either a (nano)bubble inside the cancer cell or exploding it (zapping).

“Single-cell targeting is one of the most touted advantages of nanomedicine, and our approach delivers on that promise with a localized effect inside an individual cell,” said Rice physicist Dmitri Lapotko, the lead researcher on the project. “The idea is to spot and treat unhealthy cells early, before a disease progresses to the point of making people extremely ill.”

[Source: EurekAlert]

The technique is not only good for an onco-shooting gallery. It can also be used for diagnosis because the nanobubbles are highly visible to microscopes. The researchers refer to this as a ‘theranostic’ opportunity – combining diagnostics followed immediately by therapy. The technique has been tested on human cancer cells. The next steps are trials of various methods of application.

The second announcement is less dramatic. It involves using nanoparticles to cross mucus barriers. That’s less dramatic, but it’s an important achievement. The human body has many organs with natural mucus barriers – the stomach, intestines, lungs, eyes, throat, cervix – some of which are nearly impermeable to traditional drug chemistry. The nanoparticles developed by the Johns Hopkins School of Medicine (Maryland, USA) have a special outer layer of polyethylene glycol (commercially, Carbowax), which makes it possible for the particles to penetrate mucus membranes with ease. The nanoparticles have been created with an inner layer of polysebacic acid, which can hold a variety of drug or genetic molecules, making the particles a drug delivery system that can be targeted for specific diseases. Better yet, the nanoparticles are designed to release their drug cargo as they biodegrade. In effect, the dissolving of the particles is the timer for release of the drugs, and when that’s over, the nanoparticle compounds are flushed out with normal bodily systems.

The original target for these nanoparticles is cystic fibrosis, which is notorious for creating unusually thick and sticky mucus in the lungs and gut.

The team’s work was reported recently in the Proceedings of the National Academy of Sciences. Hanes’ collaborators included cystic fibrosis expert Pamela Zeitlin, a professor of pediatrics at the Johns Hopkins School of Medicine and director of pediatric pulmonary medicine at the Johns Hopkins Children’s Center.

“Cystic fibrosis mucus is notoriously thick and sticky and represents a huge barrier to aerosolized drug delivery,” she said. “In our study, the nanoparticles were engineered to travel through cystic fibrosis mucus at a much greater velocity than ever before, thereby improving drug delivery. This work is critically important to moving forward with the next generation of small molecule and gene-based therapies.”

[Source: Nanotechnology Today]

This use of nanoparticles has many potential applications, some of which are in development.