The gecko is the poster animal for biomimetics, hence the title of my book: The Gecko’s Foot. Now, according to an article in Science, it heralds a new approach to the subject. Ever since the huge success of Velcro, derived from the hooked seeds of a burr, scientist and engineers have looked at individual species with outstanding characteristics and tried to harness their properties for use in human engineering and materials science. But, as the author of the article, S. N. Patek, from Duke University, points out, biomimetic research is burgeoning yet biomimetic products are still very thin on the ground.

The article lauds Geckskin, developed by Duncan Irschick and colleagues at the University of Massachusetts Amherst, an artificial gecko adhesion material developed by considering the evolution of geckos and the physical requirements of scaling up the gecko principle to larger surfaces than the of a gecko’s feet. Will this technique be the one that gets biomimetics out of the lab and onto the High Street?

Science, 19 September 2014, pp. 1448-9

The search goes on for the first killer graphene app. Batteries might seem a pretty humble application for such a highly touted, supposedly miraculous substance but, as any smartphone user knows, batteries are the Achilles heel of hi-tech. A lot of our gear spends a lot of time on the charger.

Micro-supercapacitors might be the answer. Power  density in some experimental graphene super-capacitor devices is several times that of standard thin-film lithium batteries but volume is a problem: graphene is only one atom thick. A Chinese team, working in China, Singapore and the USA, may have come up with the solution: creating a mesh of carbon nanotubes with interposed doped graphene sheets. They claim more than twice the power density of ordinary batteries and “a long cycle life”. Ah – how long, that is the question.

Nature Nanotechnology, July 2014

There is a small constellation of atoms – 4 manganese, 5 oxygens and one calcium – that lies embedded in a protein matrix in what is known as Photosystem II (PSII). This is the water-splitting complex in plants: the key process in photosynthesis and one which technologists would dearly love to replicate to create solar fuels. An intense effort is revealing the secrets of this cubane structure and how it performs. A paper in the August 15th issue of Science takes the structure further: the process of water splitting has 5 stages and everything up to an including stage 4 is now revealed. As the journal’s commentary has it, we are now one step away from the oxygen releasing step itself. In fact, of course, the important product if the process is not oxygen (although this has many industrial uses) but the other component  of water: hydrogen – key to the low carbon economy.

By itself, understanding the natural process  won’t enable an instant solar fix. Attempts have been made to create synthetic cubanes but the water splitting ability is a millionth of that of the natural system. PSII, like all enzymatic processes, is orders of magnitude more efficient that simple inorganic catalysis.

But that efficient ways of mimicking photosystem II will now be discovered seems inevitable. The goal is to create from air, water and sunlight liquid fuels and feedstocks such as methanol that will not only power motor vehicles (allowing all the existing infrastructure  of pipelines and filling stations to remain) but allow the chemicals and plastics industries to be fed from a carbon-neutral source. In some cases these processes will even be carbon negative in taking carbon dioxide (to be reduced by solar-generated hydrogen) from power station effluent or even the air.

Watch that cubane space!

Science, 15 August 2014, pp. 736 and 804-808

Self assembly is nature’s best kept secret. Non-scientists have always been baffled by the idea that the complex components of living things have somehow assembled themselves in the precise way needed for them to function. It is counter intuitive because in the world as we see it if you leave things to their own devices everything mixes up or falls apart – entropy rules.

But self assembly is actually nature’s greatest trick and it operates at every level from the assembly of proteins and complex multi-protein structures such as the ribosome to the behaviour of animals such as ants and termites which build complex structures on the basis of simple local chemical signals between individuals.

Technologists are now beginning to replicate this technique and the latest effort, reported in the August 15th issue of Science, involves a swarm of 1024 robots which can form any two dimensional shape you like by varying just 3 local signals: edge following, gradient formation and localization. Of course there is a difference between these technical self-assemblies and natural ones in that in the technical assemblies the overall goal has been set by the human programmers; in nature there is no master plan at all: the pattern of operation has been naturally selected to take the course it has. In the two cases the human and natural selector are playing the same roles.

Self assembly looks like being one of science’s hottest topics for decades to come. It is the underlying theme of Nanoscience: Giants of the Infinitesimal.

Science 15 August 2014, pp.795-799.