A predictive model for cytotoxicity of 20 and 50 nm silica nanoparticles has been built using so-called optimal descriptors as
mathematical functions of size, concentration and exposure time. These parameters have been encoded into 31 combinations
‘concentration-exposure-size’. The calculation has been carried out by means of the CORAL software
(http://www.insilico.eu/coral/) using three random splits of the obtained systems into training and test sets. The statistical quality
of the best model for cell viability (%) of cultured human embryonic kidney cells (HEK293) exposed to different concentrations
of silica nanoparticles measured by MTT assay is satisfactory.