Evaluation of the toxicity of oligonucleotide/cationic nanoemulsion complexes on Hep G2 cells through MTT assay.

The purpose of this study was to evaluate the toxicity of the oligonucleotide/cationic nanoemulsion complexes on Hep G2 cells through MTT assay. Complexes exhibit droplet size, zeta potential and viscosity of approximately 270 nm, +50mV, and 1.0 cP. Different parameters which may have an influence on toxicity results obtained by MTT assay, i.e. cells number, concentration of MTT reagent and the addition of Soerensen's glycine buffer were first evaluated. In the optimized conditions (1 x 10(4) cells and 0.5 mg/mL MTT), the overall results showed that the addition of increasing amounts of complexes (or nanoemulsions) lead to a progressive toxicity on cells attributed to the presence of the cationic lipid stearylamine in the formulations, whatever the medias's pH is. The IC50 was approximately 200 microg/ml. Such results open interesting perspectives on the use of these nanoemulsions as oligonucleotide delivery systems for Hep G2 cells.