Probing nanoparticle interactions in cell culture media

► Gold nanoparticle interactions with culture medium and with two cancer cells are investigated. ► Gold nanoparticles of 10, 25, 50, and 100 nm form complexes around 100 nm in cell culture media. ► PANC1 uptake more gold than Jurkat, and 50 nm particles enter cells faster than the 25 nm particles.