Live-cell imaging confirms
APH-mediated, targeted coumarin delivery
to nucleolin-expressing cells. We incubated APHs that couple a Cy5-labeled
nucleolin aptamer (red) with a polymer scaffold loaded with coumarin
(blue) with MCF-7 (top) and MCF-10A (bottom) cells, which express
high and low levels of nucleolin, respectively. After 10 min, we washed
the cells thoroughly; over the next 4 h, we observed nucleolin-mediated
cell-surface binding, APH internalization and cytoplasmic payload
release in MCF-7 but not MCF-10A cells. Scale bar = 40 μm.