  We describe the effect of optical aberrations on fluorescence fluctuations
microscopy (FFM), when focusing through a single living cell. FFM measurements
are performed in an aqueous fluorescent solution and prove to be a highly
sensitive tool to assess the optical aberrations introduced by the cell. We
demonstrate an adaptive optics (AO) system to remove the aberration-related
bias in the FFM measurements. Our data show that AO is not only useful when
imaging deep in tissues but also when performing FFM measurements through a
single cellular layer. This work paves the way for the application of FFM to
complex three-dimensional multicellular samples.
