Blog @ NanoVic - Nanotechnology Blog

Dye-sensitized solar cells are a type of solar cell which uses an organic dye to to absorb incoming photons and produce excited electrons. Have a look here for a nice diagram of one. Typically, these sorts of cells contain a transparent, conductive coating (typically an oxide such as titanium dioxide, on glass), acting as the anode. A separate coating, on the other plate, consists of platinum and acts as a catalytic conductor.

These types of coatings have their drawbacks though. The oxide films work best when they are spread on rigid, stable structures such as glass, limiting the types of structures that can be made. Platinum films are effective, but expensive to produce.

In order to tackle these problems researchers tried to replace both of the films with nanotubes. This meant finding a way to achieve the optimal parameters for transparency, conductivity and catalytic function. Ordinarily, carbon nanotubes are mid-range for these three properties. Researchers found that introducing defects into the tubes, by exposing them to ozone which adds extra chemical groups into the tube, they actually found a big increase in the catalytic function. A great example of how changes in the structures of nanomaterials can have such huge effects on their properties. The link to the research article can be found here.

The researchers are currently applying to patent this technology, which will hopefully mean cheaper, more flexible solar cells on their way to meet the demands of the ever increasing renewable energy market.

Researchers at Swansea University are developing a new, eco-friendly nanomaterial that they claim could generate as much electricity as 50 wind farms.

They are investigating ways of painting solar cells, which efficient at capturing low light radiation, onto the flexible steel surfaces commonly used for cladding buildings. This could then create buildings that could power themselves!!

Researchers are working closely with a company that produces around 100 million square meters of steel building cladding a year. If all this cladding was treated with the new solar cell material, it could be generating 4,500 gigawatts of electricity a year, the equivalent of 50 wind farms!

The people of South Australia, faced with living in the driest state on the driest continent on earth, know the value of clean fresh water. Researchers at the Ian Wark Research Institute at the University of South Australia have used a nano approach to produce clean, safe drinking water. Billions of people around the world do not have access to safe drinking water, and the result is that a child dies every 15 seconds due to water-bourne disease. Methods for purifying water often require complex and expensive equipment that is difficult to maintain in areas around the world which need this technology the most.

In this study, reported in the International Journal of Nanotechnology, silica beads were coated with an active material based on a hydrocarbon with a silicon-containing anchor. This formed a nano-layer around each bead, so called Surface enegineered silica (SES). The process works by simply mixing Surface engineered silica beads with contaminated water. After stirring for an hour and filtering out the beads the water was tested. Biological molecules, pathogens such as viruses like the Polio virus, bacteria like Escherichia coli, and Cryptosporidium parvum, which is a waterborne parasite were all removed. This process was effective across the normal pH ranges of drinking water, and the researchers attribute the removal of organic material by electrostatic attraction and immobilisation on the surface of the particles.

This is a great example of how nanotechnology is not just a ‘gimmick science’ aiming to produce endless gadgets for us, but how it is a science that can genuinely have an impact on improving the lives of many people. And also a great example of Australian nanotechnology at work!

The wikipedia entry on nanobacteria still cautiously starts by defining them as ‘a possible class of living organisms’, but two recently published, independent studies have given increased weight to the hypothesis that they are not living creatures after all.

Image credit: Martel and Young. PNAS.

The nanoscale structures containing calcium and protein were first termed ‘nanobacteria’ by geologist Robert Folk who reported them after seeing nanoparticles on scanning electron micrographs of mineral samples he’d collected from hot springs in Italy.

Ever since they were first reported, there has been controversy as to whether or not they could possibly be ‘alive’, as DNA is around 2nm wide, and some proteins are known to be bigger than the proposed size of the nanobacteria. Studies conflicted, with some reports showing that the nanobacteria could increase in number, implying an ability to reproduce (at a slow rate), yet other studies showed that no DNA could be detected in the nano-sized structures.

The two most recent papers in PLoS and PNAS show that, whilst these structures do exist and have interesting properties, they do not seem to be alive. A group from Taiwan were able to show that the nanostructures could be formed when calcium carbonate solution was incubated in a nutrient solution. A protein in the nutrient solution called albumin, commonly found in serum which is used in routine human cell culture, was found to help seed formation of these particles. No DNA was found in the particles. A team from France also found that the nanostructures of calcium carbonate could form in complex with a protein called Fetuin, and that these particles could seed formation of new particles, in a process likened to that of prions- catalytic proteins that cause mad-cow disease and scrapie but are themselves not ‘alive’.

The nanoparticles of calcium carbonate have been reported to be involved in all sorts of disease states such as arthritis, artherosclerosis and kidney stones, and while these recent studies mean they might not be living organisms, they still may have interesting medical implications. I’ll wait to see what the after-life holds for the ‘nanobacteria’!

Nanotechnology: The Power of Small, the first major television series to look at the implications of advances in nanotechnology, will begin airing on local US public broadcasting stations in April.

The series’ three programs explore critical questions about nanotechnology’s potential impact on privacy, the environment and human health: Will nanotechnology make you safer, or will it be used to track your every move? Will nanotechnology keep you young, and what happens if you live to be 150? Will nanotechnology help clean up the earth, or will it be the next asbestos?

The programme is funded by the National Science Foundation (NSF) and involves the host asking policymakers, scientists, journalists and community leaders to wrestle with difficult but essential issues about nanotechnology’s potential to impact people’s privacy and security, health and environment. Featured experts include Harvard University researcher George M. Whitesides, PEN chief scientist Andrew Maynard, and author Joel Garreau, among others.

To view the series click here

Predicting the future is never easy, but a team of scientists, journalists and policy makers was asked to do just that, looking at new and novel threats to biodiversity in the UK in the next 40 years. 

The results, published in Journal of Applied Ecology (original article), predictably included issues to do with the looming energy crises, potentially toxic nanomaterials, as well as some more out-there predictions like the threat of biomimetic robots that could become ‘invasive species’, a modern day equivalent of the devastation the cane-toad continues to cause across Australia. 

The effect of nanomaterials on biodiversity is a complex issue that definitely does require more research.  It’s not known, for example, how long various nanomaterials may persist or how easily they can be dispersed in different environments. 

Science writer Matt walker spoke to New Scientist about the project, saying that:

“The purpose of the exercise was to raise awareness. The more into the future you try to look, the more uncertain it gets, but that doesn’t mean we shouldn’t take such threats seriously.  It’s important to look beyond the immediate well-known threats and try to predict the next great challenge to biodiversity.”

It is hoped that the paper will stimulate further research into the areas identified by the group.

The line between artificial and biological life is becoming increasingly blurry,and the latest development is robots that feed themselves. It’s not a new concept to create robots which don’t need ‘refueling’ so to speak, of course you can whack a few solar cells on to create a renewable fuel source. But the Bristol Robotics Laboratory has actually created the worlds first robot that eats unrefined biological material to produce it’s energy.

So what does a robot eat when it’s hungry? EcoBotII eats flies, generating electricity from a microbial fuel cell which digests the chitin in the exoskeleton of the insects. And although the power output is tiny, EcoBotII won’t break any speed records at a measly 13 cm per hour, it is able to be fuelled for 2 weeks on just 8 flies! At this stage EcoBotII has been ‘fed’ flies, but next generation EcoBotIII will not only attract it’s own food with a trap system using attractant pheremones, it will be the first complete artificial digestive system, able to excrete it’s own waste.

Why make a robot that can eat insects? One group that has been very interested, says scientist Allan Winfield, is organic farmers, who would be able to control pests without using pesticides, with the added bonus that the robots are able to ‘poo’ out nutrient rich fertiliser!

Just as we’ve all (hopefully) finally made the switch to energy-saving fluorescent light bulbs, researchers at the University of Glasgow have announced a way of utilising LEDs for household lighting.

LEDs are currently used in computers and mobile phones and are significantly more energy efficient, but because of the way they are designed they trap a lot of light, and have not been bright enough for household lighting uses. However, by creating microscopic holes in the surface of LEDs, more light can escape resulting in a brighter light for no more energy consumption. But the process is costly and inefficient.

Researchers at the University of Glasgow have used nanoimprint lithography to create the holes, which can be done on billions of LEDs for much lower cost. LEDs also last far longer than even current energy-efficient fluorescent bulbs.

Nanotechnologists must be very good at ‘thinking outside the square’ or even just at ‘thinking outside’ with many of their inspirations coming from nature. 

Similarly to the article on ‘gecko tape’, scientist at a US university have developed a novel responsive material inspired by the Venus flytrap. Venus flytraps work by material on the leaves snapping rapidly from a concave shape to convex when hairs on the leaves are triggered. To imitate this, the scientists have developed a polymer surface covered with tiny holes capped by thin lenses that can snap between convex and concave conformations when triggered. 

This material has great potential for creating release-on-command coatings and could allow for the removal of superglues, wallpapers and paints without toxic solvents, as well as surfaces with responsive reflective properties, such as road signs that change their reflectivity with changing weather conditions. 

They are also working on a Venus flytrap-gecko hybrid, investigating the adhesion and release properties of geckos toes as a means of controlling the sticking and releasing of this new material.

So what will they be inspired by next?……..

The premier journal Nature Nanotechnology has published two free online papers as part of a global effort to raise awareness and stimulate research into poverty and human research. The articles discuss how nantoechnology might impact on countries of the developing world. The first publication, entitled Nanotechnology and the Challenge of Clean Water, presents the opinion that although nanoscience does offer a great deal of potential for increasing global access to appropriate drinking water, care must be taken to ensure that nanotechnology transfer is accompanied by technology adaptation and technology adoption to suit the country in which it is applied. The second publication, Are Natural Resources a Curse?, presents an interesting discussion pertaining to the changes in global demand for elemental resources with emerging technologies, and how this can have a very strong impact on nations and commmunities. For example, should carbon nanotubes emerge as a contender to replace copper wires for transmission of electricity, countries such as Zambia may lose out since a quarter of its foreign exchange relies on minerals such as copper. Equally, it might be possible that nanotechnology adds value to a particular country’s exports in a way that mitigates heavy reliability on a particular resource. Follow the links to the articles above for more interesting aspects relating to nanotechology and the developing world; an editorial also addresses the issue. Clearly it’s a topic which requires further multidisciplinary discussion.