Fig. 3. Cellular uptake study of functional DNA nanotubes targeting miR-155. (A) CLSM imaging of the internalized NTR155 in H1299 non-small cell lung cancer (NSCLC) cells. Cells were incubated with Cy3-tagged NTR155 (nanotube concentration: 50 nM; Cy3 fluorophore concentration: 300 nM) for 12 hours before imaging. The nucleus was stained with Hoechst 33342 (blue). Scale bar: 20 μm. (B) Flow cytometry analysis of the internalized NTR155 at different concentrations. A Cy3-tagged antisense oligonucleotide (ASON, miR-155 capturing unit) was also used as a control. The concentrations of ASON or capturing units of DNA nanotubes were 300 nM, 600 nM and 900 nM. The transfection time was 12 hours. (C) Flow cytometry evaluation of the transfection efficiency of all three types of capturing unit designs: single-stranded (NTR155), duplex (NTR155D) and hairpin (NTR155H). The capturing unit concentration used in this experiment was 300 nM. The transfection time was 12 hours. (D) Histograms showing the quantification of the internalized amount of DNA nanomaterials in (B). (E) Histograms showing the quantification of the internalized amount of DNA nanomaterials in (C). The data are representative of three separate experiments (mean ± S.E., n = 3) Student's t-test, P-values: *P < 0.05, ^#P < 0.05.