Richard Feynman, the eccentrically brilliant American physicist, once described the immense possibilities offered to scientific innovators working at the molecular end of the size spectrum.

The title of Feynman’s famous 1959 talk to the American Physical Society summed up his thesis: “There’s plenty of room at the bottom”. It was the first time anyone had suggested in such a high-profile way that it may one day be possible to “swallow the doctor” in the form of tiny robotic pills that could perform internal surgery under autonomous control.

Half a century later, Klaus-Peter Zauner has taken up Feynman’s challenge with an ambitious goal of developing molecular computers. He believes that living organisms, and the biological molecules they create and use, offer new research opportunities that could revolutionise computing in its widest sense. The future he envisages will be populated by swarms of extremely small robots or intelligent materials that could be programmed to carry out the most complex or menial of tasks, from heart surgery to clearing up an oil spill.

Crucially, Zauner says, biological systems can provide us with the inspiration to make computers based on a radically different hardware architecture to the silicon-based machines we have been building for the past 50 years. He believes that this new breed of molecular computer, based on the information processing of living organisms, could be far more energy-efficient than existing devices and be capable of repairing themselves, as well as being so small that they could be put just about anywhere they are needed, from the retina at the back of the human eye to a space probe destined for Mars.

“Life without information processing is impossible,” explains Zauner, a researcher in the School of Electronics and Computer Science at the University of Southampton. “As a consequence of this, all organisms – even the simplest microbes – have developed sophisticated and highly efficient ways of computing at the molecular scale. I want to better understand how they do this and harvest their mechanisms and materials for technical applications.”

Computing passion

Zauner, who spent his school days in the German town of Schwäbisch Gmünd, developed his passion for computers in early childhood after an even earlier obsession with rockets and space travel – he built his first computer at the age of 12. But he took the conscious decision not to study computing at university, choosing biochemistry instead to broaden his academic outlook. It was then that he began to realise the possibility of using biological molecules as computers.

“All living matter is highly organised and only a small subset of its states is compatible with being alive. Without constantly maintaining its organisation, a task which requires information processing, physical entropy would quickly turn animate matter into dead matter,” he says.

‘Life without information processing is impossible... As a consequence of this, all organisms – even the simplest microbes – have developed sophisticated and highly efficient ways of computing at the molecular scale.’

‘We have now a well characterised model system we can use for intracellular molecular information processing.’

International recognition of his research soon followed his decision to explore this new area of computing. In 2005, Zauner was awarded a Microscoft Research European Fellowship, funding that allowed him to automate the process of exploring the capabilities of enzymes and networks of enzymes in a process he calls “autonomous experimentation”.

“We are developing a system where the computer performs experiments – using lab-on-chip micro fluids technology – and decides what experiments should be performed on the basis of machine-learning algorithms that formulate working hypotheses,” he says.

On a grander scale, Zauner is one of the many scientists trying to understand how to improve what some have called the “carbon-silicon” interface – in other words how to marry the information processing of carbon-based living systems, including the human brain, with the silicon-based architecture of the computer.

It is well established, for instance, that silicon-based computers are excellent at the logical processing of data – they are good for example at computing every possible move in a game of chess. The human brain, however, is supreme at the more holistic level of pattern recognition, such as understanding speech and recognising faces.

“If we look at the human brain as the most powerful information processor we know, and take a crude, high-level view, we have a system where one half deals with rational logic reasoning and the other is responsible for a more holistic, pictorial fusion of information,” Zauner says. “That both halves exist after many millions of years of evolution indicates that, in practice, it is useful to have both modes of information-processing available.”

Half a brain

“Computer scientists and engineers have built only half of a brain, a very powerful version of the logic mode of information processing, and it is quite possible that this other mode can be implemented more easily with carbon,” he says.

One of his projects has been to attach a living, single-celled organism (a slime mould) to a six-legged robot designed not to fall over no matter what signals it receives from the microbe. “Did we succeed? Not in the sense that the robot would do anything particularly interesting. But we have now a well characterised model system we can use for intracellular molecular information processing – including the capability of keeping the living cell alive in micro fluidic chips for several days,” Zauner says.

The slime-mould cells can even be kept in their natural dormant state for many weeks before being activated to control the robots – a potentially useful trait.

Klaus-Peter Zauner’s six-legged robot is controlled by a slime mould that avoids light.

Most importantly, Zauner emphasises that he is not simply trying to construct a molecular computer based on conventional architecture. “Rather than trying to train a molecule to follow the rules of a logic gate – I think electronics and photonics are better at that – my team investigates what macromolecules can naturally do and then sees how the innate capabilities of the molecule can be exploited by a suitably tailored computing architecture,” he says.

As to when we will see such computers in everyday use, Zauner says that he does not expect to see biological computers replacing conventional computers in his lifetime. “But I would expect simple molecular computers – on the level of a washing machine’s control – to become a standard technology for synthetic biology within 10 to 15 years, and molecular-controlled robots to become available within 30 years,” he says. So it may take time, but there’s still plenty of room for research at the bottom.

Steve Connor is the Science Editor of The Independent

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