Researchers from the School of Computing at the University of Kent have made significant advances in molecular computing.

These include defining the fundamental limits of such 'biological computers'.

Molecular computing attempts to use components of organisms (eg genes) to run calculations inside living cells. Currently, most of the work in this area is theoretical or concerned with future applications of the technology, such as molecular computers being used to release drugs into the body or enhance our ability to study and learn from biological systems.

In a paper published by the Journal of the Royal Society Interface, the University's Dr Dominique Chu and his PhD student Radu Zabet have, by defining the fundamental limits that molecular computers are subject to, also addressed the question as to how fast they can perform a computation -- a prerequisite for the design of 'living machines'.

Dr Chu explained: 'There are a variety of different mechanisms by which living organisms perform computations, and they do so at many different levels. Examples include the nervous system in higher organisms or even individual proteins. Understanding what constrains the efficiency and the speed of these computations is not only of practical relevance -- for example, in the context of engineering purpose-built novel life forms ie synthetic biology -- but will most of all provide new insights into the design principles of living systems.

'Our research demonstrates that the speed of bio-molecular computers is fundamentally limited by their metabolic rate or their ability to process energy. One of our main findings is that a molecular computer has to balance a trade-off between the speed with which a computation is performed and the accuracy of the result. However, a molecular computer can increase both the speed and reliability of a computation by increasing the energy it invests in the computation. With molecular computers this energy may be derived from food sources.'

Dr Chu also explained the importance of these findings for computing in general. 'This is one of the first papers deriving fundamental limits on the speed of bio-molecular computers,' he said. 'Our results are potentially of high theoretical and practical importance. Much work remains to be done to fully understand its implications for the field of molecular computing but also for our understanding of design principles of the living world.'