The invention relates to an in vitro method for quantifying nano-objects of mammalian skin cells comprising the following steps: a) Collecting mammalian corneocytes; b) Analysing the surface topography of corneocytes at nanoscale resolution; c) Identifying subcellular objects of typical size smaller than 500 nm with a circularity index > 0.5 (circular nano-objects, CNOs); d) counting these CNOs; e) relating the number of CNOs to a unit area for obtaining a density parameter, especially a structural index in the form of a dermal topographic Index, DTI.
