The optical microscopy of single molecules has recently been beneficial for many applications, in particular in biology. It allows a sub-wavelength localization of the molecules and a subtle probing of the spatio temporal nano-environment of the molecules (1). For many bio-applications, more photostable nanoprobes than fluorescent ones are desirable. For this aim, we developed far-field photothermal methods based on absorption instead of luminescence(2). Such approaches do not suffer from the inherent photophysical limitations of luminescent objects and allows the ultra-sensitive detection of tiny absorbing individual nano-objects such as gold nanoparticle down to 1.4nm or semiconductor nanocrystals(2). Approaches were further developed to measure the diffusion of proteins labelled with 5 nm gold nanoparticles in living cells for arbitrary long times(3). Complementary to studying an individual molecule for arbitrary long times, it is also crucial to study a large ensemble of molecules on a single cell while keeping the sub-wavelength localization provided by single molecule microscopy. Several super-resolution imaging methods were developed recently toward this aim. However, none of them were able to image the dynamical properties of endogenous proteins at high densities on living cells with spatial resolution below 100nm on large fields. We developed a new super-resolution technique, named universal PAINT (uPAINT) which provides super-resolved images as well as long single-molecule trajectories (up to tens of seconds) at unprecedented high densities on living cells (4). (1) Heine et al., Science (2008) (2) Berciaud.et al Phys Rev Lett (2004) (3) Lasne et al Biophys. J. (2006), Rossier et al, submitted (4) Giannone et al . Biophys. J. (2010)< Leer menos