Magnetic Resonance Imaging (MRI) is a technique based on Nuclear Magnetic Resonance (NMR). The NMR signal is produced by spinning nuclei, typically hydrogen (1H) and carbon (13C), which have been deflected from their equilibrium positions by radiofrequency pulses. The technique is non-invasive, can probe optically opaque objects and is able to provide a wealth of chemical and physical information. MRI relies on the application of magnetic field gradients, which spatially locate nuclei by their spinning frequency because this is dependent on position. Image contrast is produced through differences in the density of nuclei within a pixel or the relaxation time of the nuclei (the time taken for nuclei to return to their equilibrium positions).
Work done in Dr Britton's group uses MRI to probe chemical systems. In these systems image contrast is produced by transition metal ion complexes which oscillate between two oxidative states and affect the relaxation time of surrounding water molecules, depending on their oxidation number. MRI measurements are able to not only visualise the oscillations, showing waves and patterns (below) but are able also to probe the chemistry and underpinning mechanisms behind pattern formation in these systems. A collaboration with Dr Timmel at Oxford University has looked into how these chemical waves can be manipulated by magnetic field gradients. Motivation for this work lies not only in better understanding these complicated chemical systems, but also in understanding how these model chemical systems can relate to wave and pattern formation in biology.
Other areas of research include Redox chemistry in chemical and biological systems, the development of MRI contrast agents, oscillatory and autocatalytic reactions, flow and diffusion in porous media and kinetics and mixing effects in micro-reactors. MRI is a powerful technique and able to solve problems in chemistry, chemical engineering, physics, biosciences and materials, both within academia and also in industry.
Dr Melanie Britton, School of Chemistry
Tel: 0121 414 4391