(712e) Aggregation State Determines Uptake, Intracellular Processing, and Long-Term Fate of Single-Walled Carbon Nanotubes in Mammalian Cells

The intrinsic fluorescence of single-walled carbon nanotubes (SWCNTs), which exhibits exceptional photostability, near-infrared (NIR) tissue-penetrating emission, and microenvironmental sensitivity, makes them ideal candidates for a variety of biomedical imaging and sensing applications. Single-stranded DNA was found to disperse SWCNTs in water and enable their uptake into mammalian cells through an energy-dependent endocytosis mechanism. Previous empirical models of cellular uptake have been introduced that assume single SWCNTs are interacting with the cell membrane. Here, we show that DNA-wrapped SWCNTs reversibly aggregate in the presence of media containing serum proteins and this loose aggregation significantly affects the manner in which the SWCNTs interact with mammalian cells. We show that SWCNT aggregation not only alters the rate of uptake into the cells but further affects the endosomal processing and expulsion of the internalized material. These effects are highly cell-type dependent. Future work includes the development of a cellular uptake and expulsion model that accounts for the aggregation state of SWCNTs.