Surface roughness and charge influence the uptake of nanoparticles: fluorescently labeled pickering-type versus surfactant-stabilized nanoparticles.

The influence of surface roughness and charge on the cellular uptake of nanoparticles in HeLa cells is investigated with fluorescent, oppositely charged, rough, and smooth nanoparticles. Flow cytometry, cLSM, and TEM reveal that rough nanoparticles are internalized by the cells more slowly and by an unidentified uptake route as no predominant endocytosis route is blocked by a variety of inhibitory drugs, while the uptake of smooth nanoparticles is strongly dependent on dynamin, F-actin, and lipid-raft. Negatively charged nanoparticles are taken up to a higher extent than positively charged ones, independent of the surface roughness.