Criteria impacting the cellular uptake of nanoparticles: A study emphasizing polymer type and surfactant effects

A detailed understanding of the particle–cell interaction is essential and of immense interest in order to create a “specific carrier” for each particular application. In this paper, the effect of the surfactant type (non-ionic vs ionic) and polymer nature on the cellular uptake of fluorescent polystyrene and poly(l-lactide) nanoparticles was studied on HeLa cells. Nanoparticles in a size range from 100 to 160 nm were synthesized by the miniemulsion process. The particles were detected in cells by confocal laser scanning fluorescence microscopy and flow cytometry. It was found that the influence of the surface charge is greater than that of the polymer type itself. In fact, particles stabilized with cationic surfactant were incorporated in a large number irrespective of polymer type. Cellular pathways at ultrastructural level were studied by transmission electron microscopy in more detail to shed light on the particle–cell interaction based on the material properties. The criteria governing the cellular uptake of nanoparticles based on the polymer and surfactant types are finally established.