Nanometric emulsions encapsulating solid particles as alternative carriers for intracellular delivery.

Aim: Formulate nanometric oil droplets for encapsulating solid nanoparticles and assess their interactions with cells.

Materials & Methods: Soybean oil droplets, stabilized by Pluronic F68 surfactant, incorporating hydrophobically modified fluorescent silica, nanoparticles were obtained. Cytotoxicity over time, internalization, subsequent intracellular localization and internalization pathways were assessed by microscopy (fluoresence and TEM) in vitro with HeLa cells.

Results: Oil droplets encapsulating solid nanoparticles are readily internalized by HeLa cells like free nanoparticles but the intracellular localization differs (nanoemulsions less colocalized with lysosomes) as well as internalization pathway is used (nanoemulsions partially internalized by nonendocytic transport). No cytotoxicity could be observed for either particles tested.

Conclusion: Our results confirm that nanometric emulsions encapsulating solid nanoparticles can be used for alternative and multifunctional intracellular delivery.