Abstract

The fundamental goal of optical microscopy is to visualise and thereby enable the study of dynamics on the microscopic or even nanoscopic scale. The past decades have been dominated by fluorescence-based approaches, in particular in super-resolution methodologies. Despite the advantages of fluorescence imaging, the requirement of introducing labels can be both complex and perturbative, while limited photophysics and photochemistry limits imaging speed, precision and duration. I will highlight the capabilities of an alternative approach to optical microscopy based on light scattering called interferometric scattering microscopy. Contrary to intuition, I will show that iSCAT can achieve sensitivities approaching and possibly rivalling those of a fluorescence microscope including label-free imaging of single molecules. Importantly, this sensitivity has wide-ranging applications for studies of nanoscale phenomena in general, such as phase separation, dynamics at interfaces, bilayers or biological filaments.