2010 Franklin medal and prize
Professor Thomas Duke
University College London
For the application of physical principles to the development of elegant molecular sorting devices, for providing new insights into the organising principles of cells and for his primary contributions to a new generation of theories of how the inner ear works.
Professor Thomas Duke first worked on DNA separation technology, providing a theoretical elucidation of the microscopic dynamics underlying the capillary electrophoresis methods. The work has enabled high-throughput DNA sequencing and the pulsed field gel electrophoresis techniques used in DNA fingerprinting. He pioneered the development of microfluidic separation methods, demonstrating that they could analyse DNA in seconds rather than hours, and introduced the concept of continuous lateral separation in asymmetric arrays of microfabricated pillars. The ideas are now being developed to sort blood cells, viruses and nanoparticles. Duke's research on the physical basis of cellular processes has focussed on sensory and motor systems.
He has shown how the molecular structure of the myosin protein is designed to permit many molecules to work together efficiently to drive muscle contraction. His work on the clustering of membrane receptors, showing that neighbouring receptors can significantly enhance a cell's internal response to extracellular signals, has been very influential. The theory was initially developed to explain the remarkable chemosensory ability of bacteria, but has since found applications in a wide range of receptor systems.
Duke has also shown that the propagation of allosteric states in multiprotein complexes can account for the stochastic switching of the bacterial rotary motor. Duke was one of the proponents of the concept of 'self-tuned criticality', which posits that sensory systems achieve the combination of high sensitivity and wide dynamic range by being poised at the onset of an instability. This theory has been strikingly confirmed in the auditory system of lower vertebrates, where the sensory hair bundles have been found to oscillate spontaneously and respond to mechanical stimuli in a characteristic nonlinear fashion.
While the extension of this theory to human hearing remains tentative, Duke has shown that it is consistent with the observed propagation of nonlinear waves within the cochlea that carry sound energy of different frequencies to different locations, and that it can provide an explanation of a wide range of psychophysical phenomena.