Over the last few years, parallel developments in imaging technologies, optical probes, new nanomaterials and genetic engineering have allowed the fast emergence of single molecule fluorescence techniques and their application to biological imaging. These techniques now provide unprecedented details on the spatial and temporal heterogeneities of nanoscale biological processes and are just starting to reshape our understanding of molecular organizations and interactions in cells and tissues. An emerging cell biology concept is that spatially defined subcellular compartments (e.g. immune and neuronal synapses, lipid microdomains, membrane cavities…) influence the diffusion, the location, the interactions, and thus the activity of subpopulations in an otherwise homogenous pool of the same protein. Stable nanoscale cellular compartments can thus accommodate discrete molecular interactions that deviate from the classical laws of mass action at the ensemble level, thereby allowing a few copies of a biomolecule to influence whole cell processes.
In the Single Molecule Biophotonics Group, we aim at understanding how such discrete nanoscale interactions in plasma and nuclear membranes are capable of finely modulating normal and pathological cellular signaling and responses. For this, we design and implement ultra-sensitive imaging tools and probes that quantitatively report and influence such interactions in living cells and also in whole animals. Using highly interdisciplinary approaches, at the interface between cell and molecular biology, biological chemistry, biophysics, nanomaterial sciences and optical imaging, we seek to grasp the fundamental molecular mechanisms that govern nanostructures/protein function relationships during cellular signal processing, integration and regulation. We also aim at providing novel probes and imaging techniques for molecular diagnostics and therapeutics.