Final Activity Report Summary - CEMIM (Development and application of combined scanning electrochemical -confocal microscopy for investigating lateral diffusion process in model biomembranes) Thin films are of huge commercial and fundamental importance across many areas of science, from the life sciences to engineering and materials. In the life sciences, membranes separate the internal components of a cell from its external environment and the transport of chemical species along or across the membrane is fundamental to life itself. In materials and engineering, thin films are used to protect everyday objects from their environment or to give objects special properties. Materials and the life sciences come together in the area of sensors, where tailored, chemically-functionalised interfaces are used to selectively recognise and register particular molecules. Biochemical sensors have the potential to revolutionise point of care diagnostics. This project has developed new techniques which are able to provide greater insight into the way in which ions and molecules diffuse and react with specific thin films. First, a new methodology combining tiny electrodes with optical (fluorescence microscopy) detection has been developed and used to study proton diffusion at model biomembranes. Such studies are important in revealing the mechanisms by which protons move along membranes, which is a basic process in the functioning of living cells. The method is essentially a time of flight imaging technique in which the tiny electrode dispenses protons towards a small part of a membrane and the optical microscopy method registers the resulting dispersion in real time. To achieve this, the membrane or solution is labelled with pH-sensitive reporter molecules. Second, pure microelectrode (scanning electrochemical microscopy) methods have been developed for probing diffusion and reactivity in ultrathin films on electrodes. Techniques have been developed for measuring diffusion and charge propagation in synthetic polymer films, which is significant as these are key materials for sensor and energy applications. Novel materials have been developed for hydrogen evolution and models have been developed to explain their intrinsic characteristics and reactivity. This is an area with huge further potential, given the prime issues of energy and the hydrogen economy for the 21st Century.
