Labeling nanoparticles: Dye leakage and altered cellular uptake

S Snipstad, S Hak, H Baghirov, E Sulheim, Y Mørch, S Lelú, Eva Haartman von, M Bäck, KPR Nilsson, AS Klymchenko, C de Lange Davies, AKO Åslund

Research output: Contribution to journalArticleScientificpeer-review

74 Citations (Scopus)


In vitro and in vivo behavior of nanoparticles (NPs) is often studied by tracing the NPs with fluorescent dyes. This requires stable incorporation of dyes within the NPs, as dye leakage may give a wrong interpretation of NP biodistribution, cellular uptake, and intracellular distribution. Furthermore, NP labeling with trace amounts of dye should not alter NP properties such as interactions with cells or tissues. To allow for versatile NP studies with a variety of fluorescence-based assays, labeling of NPs with different dyes is desirable. Hence, when new dyes are introduced, simple and fast screening methods to assess labeling stability and NP–cell interactions are needed. For this purpose, we have used a previously described generic flow cytometry assay; incubation of cells with NPs at 4 and 37°C. Cell–NP interaction is confirmed by cellular fluorescence after 37°C incubation, and NP-dye retention is confirmed when no cellular fluorescence is detected at 4°C. Three different NP-platforms labeled with six different dyes were screened, and a great variability in dye retention was observed. Surprisingly, incorporation of trace amounts of certain dyes was found to reduce or even inhibit NP uptake. This work highlights the importance of thoroughly evaluating every dye–NP combination before pursuing NP-based applications.
Original languageUndefined/Unknown
Pages (from-to)760–766
JournalCytometry Part A
Issue number8
Publication statusPublished - 2017
MoE publication typeA1 Journal article-refereed

Cite this