Many of the biological functions of a cell are dictated by the intricate motion of proteins within
its membrane over a spatial range of nanometres to tens of micrometres and time intervals of
microseconds to minutes. This rich parameter space is not accessible by fluorescence
microscopy, but it is within reach of interferometric scattering (iSCAT) particle tracking.
However, as iSCAT is sensitive even to single unlabelled proteins, it is often accompanied
by a large speckle-like background, which poses a substantial challenge for its application …

Tracking the diffusive mobility of individual membrane proteins within the cell offers a route
to unravel how protein function is sculpted by the architecture of the membrane and its
constituents. To meet this challenge fully, however, demands a high resolution in both space
and time which exceeds the capabilities of fluorescence microscopies. Interferometric
scattering (iSCAT) microscopy is an emerging fluorescence-free technique highly suited to
the sensitive detection and precise tracking of nanoscopic biological entities, including …