Effect of oligonucleotide dimensionality on endocytosis. (A) Cy5–ssDNAs
cannot enter C166 cells in amounts detectable by confocal microscopy.
(B) However, with their 3D architecture, Cy5–SNAs that contain
the same total DNA concentration can readily enter cells, starting
from binding to the cell membrane 30 min after incubation to populating
the cytosol 2 h after incubation. (C) Encapsulation of Cy5–ssDNAs
with DharmaFECT, a conventional cationic transfection agent, led to
the tracing of the cell border by Cy5–ssDNAs without significant
intracellular accumulation. (D) Hollow Cy5–SNAs enter cells
with kinetics and degree comparable to Cy5–SNAs. Reproduced
with permission from ref (14). Copyright 2013 National Academy of Sciences.