Physical landscapes in biological membranes: physico-chemical terrains for spatio-temporal control of biomolecular interactions and behaviour.

The evolving complexities of biological membranes are discussed from the point of view of potential roles of the physical constitution of the membrane. These include features of the surface and dipole potentials and membrane 'rafts'. These properties are outlined; they emphasize that protein-lipid and specific lipid environments are influential parameters in how biomolecular interactions may take place with and within membranes. Several fluorescence detection technologies directed towards measurement of these properties are also outlined that permit high-resolution experimental determination of intermolecular interactions with membranes by measuring small changes of these potentials. These point to the possibility that the membrane dipole potential in particular is enormously influential in determining the behaviour of receptor and signalling systems within membrane rafts, and offers the means of a novel mechanism for biological control.