The first biological quantum light microscope used squeezed light in an optical tweezer to probe the interior of a living yeast cell. In experiments it was shown that squeezed light allowed more precise tracking of lipid granules that naturally occur within the cell, and that this provided a more accurate measurement of the local viscosity of the cell. Viscosity is an important property of cells that is connected to their health, structural properties and local function. Later, the same microscope was employed as a photonic force microscope, tracking a granule as it diffused spatially. This allowed quantum enhanced resolution to be demonstrated, and for this to be achieved in a far-sub-diffraction limited microscope.