Cell penetration of NYAD-201 and its linear analog NYAD-209 in 293T cells. Confocal microscopy images of 293T cells incubated for 20 hours at 37°C with FITC-conjugated peptides. Upper panel: Left, Differential Interference Contrast (DIC) image of cells with FITC-β-Ala-NYAD-209; Center, FITC fluorescent image of the same cells with FITC-β-Ala-NYAD-209; and Right, Overlay of DIC and FITC fluorescent images. Lower panel: Left, DIC image of cells with FITC-β-Ala-NYAD-201; Center, FITC fluorescent image of the same cells with FITC-β-Ala-NYAD-201; and Right, Overlay of DIC and FITC fluorescent images. A total of 200 cells were scored in each treatment with FITC-β-Ala-NYAD-209 or FITC-β-Ala-NYAD-201. The percentage of cells in the population that exhibited the internal staining is shown at the bottom right of the middle panel.