Nanoemulsões catiônicas: caracterização físico química e avaliação da toxicidade em caenor habditis elegans

Abstract

In recent years, gene therapy has emerged as a promising approach in the treatment of different diseases. Cationic nanoemulsions appear as an alternative strategy to the use of viral carriers. However, the toxicity of cationic nanoemulsions has been related to the cationic lipid used in its composition. So the objective of this study was to produce and characterized cationic nanoemulsions composed by differ- ent concentrations of DOTAP or oleylamine, relating these properties to their toxicity in vivo. Nanoemulsions were prepared by the spontaneous emulsification procedure and characterized just after preparation, at different pH and in culture medium. Their toxicity was evaluated in C. elegans model. They presented narrow distributed (Span<2) droplet size (150-400 nm) and positive and progressive zeta potential. Their charge inverted to negative values and their droplet sizes became polydisperse (Span>2) in M9 culture medium, which may be related to the adsorption of salts and to a partial annulation of emulsions charge in the medium pH. Cationic nanoemul- sions (at high DOTAP and oleilamine concentrations) presented lower survival rates than blank nanoemulsions. DOTAP presented lower LD50 than oleylamine. The low toxicity was not correlated to formulations physicochemical properties, but to the ca- tionic lipid final concentration in medium. No toxicity on reproduction or alteration in worm’s body lenght were observed for DOTAP or oleylamine formulations, although they were in fact internalized by the worms.