Opportunities and Challenges of Single Protein Detection with iSCAT

In recent decades large efforts have been made to push optical imaging to the limit, for example for detecting very small proteins. Great achievements have been obtained with fluorescence microscopy, both in terms of localization precision and study of the dynamics of different molecules. Despite the constant improvements, fluorescence-based methods suffer from intrinsic limitations, such as the finite number of emitted photons and photo damage, which limits the temporal resolution and the duration of a measurement. Furthermore, if the molecule of interest is intrinsically non-fluorescent, it has to be labelled with a suitable fluorophore, which in case of biological molecules could interfere with their activity and behavior.