Figure 2

Photoacoustic “nanobombs” selectively disrupt acidic vesicles.

(a) A549 cells were pretreated with LysoTacker Green (green dots) for 1 h followed by incubation with FA-SWCNT-6G (red dots). The dynamic intracellular distribution was monitored by confocal fluorescence microscopy at 15, 30 and 60 min after FA-SWCNT-6G incubation. Yellow puncta depict colocalization of Lysotracker (green) and FA-SWCNT-6G (red) dots. The bottom panel shows the phase contrast of A549 cells. Scale bars = 10 μm. (b,c) A549 cells were pretreated with LysoTracker Green for 1 h followed by incubation with FA-SWCNT-6G for another hour. Cells were then irradiated or not for 15 min and (b) subjected immediately to confocal microscopy. Scale bars = 5 μm. (c) Intracellular vesicles were quantitatively ranked by size (<1μm or >1 μm) in cells without (left panel, n = 44) or with irradiation (right panel, n = 47). The percentage of each distribution is shown. (d,e) A549 cells were incubated with SWCNTs for 1 h and then treated with laser for 15 min. TEM showing vesicle morphology of cells before (d) and after (e) laser irradiation. Scale bar = 2 μm. Enlarged images show intracellular vacuoles (cyan arrows) and perforation of plasma membranes (orange arrows).