Research Fellows Directory
Professor Paul French
Imperial College London
My work concerns the development and application of new fluorescence imaging and measurement technology to create and address opportunities for biomedicine, particularly to understand the roles and interactions of proteins in order to develop therapies for disease. Fluorescence is the characteristic emission from specific molecules (“fluorophores”) that can be used as molecular “labels” for proteins in cells and tissue and are particularly useful to study the biomolecular interactions that make up cell signalling processes. In some cases biomolecules in cells and tissue fluoresce intrinsically and can be used to report on changes in cell metabolism and in structural tissue components such as collagen, which can change as a result of disease.
Fluorescence intensity imaging can map the localization - and colocalisation - of specific proteins, from which interactions may be inferred but this is limited by the (~200 nm) spatial resolution of optical instruments. Thus we usually cannot image proteins or their interactions directly. We are addressing this challenge by developing super-resolving microscopes, and by utilising spectroscopic readouts, e.g. of Förster resonant energy transfer (FRET), which is the transfer of excitation energy from one fluorophore to another that can only occur when they are collocated within a few nm. If one fluorophore is excited, it loses energy faster due to this energy transfer, which leads to a decrease in its fluorescence decay time when it is excited by an ultrashort pulse. By mapping the change in this fluorescence “lifetime” imaging, we can image protein-protein interactions that lead to FRET to study the spatio-temporal properties of cell signalling. My group is implementing this fluorescence lifetime imaging (FLIM) in automated microscopes for high throughput applications including drug discovery, as well as in endoscopes and tomographic instrumentation for in vivo studies and for clinical diagnosis.