Evaluating the effect of assay preparation on the uptake of gold nanoparticles by RAW264.7 cells

BACKGROUND Cell culture conditions can greatly influence the results of nanoparticle (NP) uptake assays. In this study, 10 nm gold nanoparticles (AuNPs) and RAW 264.7 macrophages were used as a model system, while instrumental neutron activation analysis (NAA) was used as the elemental analysis technique to determine AuNP levels produced by the various culturing conditions. Static plate-based and insert-based culture conditions were compared with a dynamic suspension culture to evaluate the conditions' effect on the rate and extent of AuNP uptake. RESULTS The results indicate that a dynamic culturing condition allows for the greatest NP uptake (approximately 3-5 times over the adherent conditions), whereas the plate-based assays have the initial highest rate of NP incorporation. CONCLUSIONS These data highlight the importance of judiciously choosing the assay conditions prior to evaluating NP uptake.