Differential sub-cellular processing of single-wall carbon nanotubes via interfacial modifications

Strategies for cell-specific targeting and delivery of carbon nanotubes have made significant advancements over recent years. However, control of sub-cellular localization, an important criterion for many biomedical applications, remains largely unexplored. In this work, we experimentally demonstrate how different molecules that are used to non-covalently suspend hydrophobic SWCNTs in aqueous conditions also influence cellular processing and localization. We utilized complementary imaging modalities to show that SWCNTs dispersed using the membrane active tri-block copolymer Pluronic (R) F-127 (PF127) were endocytosed into cells by the millions but eventually escaped endosomes and altered F-actin structures. In contrast, SWCNTs dispersed with the protein bovine serum albumin (BSA) were endocytosed into cells at similarly high levels but remained in the endosomal pathway, ultimately co-registering with endoplasmic reticulum and vesicles. Interestingly, cellular exposure to SWCNTs-BSA in the presence of the endosome disrupter, chloroquine, led to altered F-actin structures that were similar to the alterations induced by cellular exposure to SWCNTs-PF127. These results suggest that PF127 facilitated endosome escape and that SWCNTs might have an energetically favorable interaction with stiff, filamentous structures inside the cell. Thus, our results provide a design principle for non-covalent surface modifications of SWCNTs that do not degrade the desirable, intrinsic SWCNT properties but provide differential trafficking to intracellular compartments for sub-cellular biomedical applications.