Fig. 4.

13 nm AuNPs induce apoptosis by mitochondrial damage. a FCM analysis with Rho 123 staining on the loss of ΔΨm induced by 3, 13, and 45 nm AuNPs, respectively. b Statistical results from three independent FCM analyses. **P < 0.01, compared with control. c Time-lapse imaging of cells stained with Rho 123 after treatment with 13 nm AuNPs for 8 h. Scale bar 20 μm. d Fluorescence imaging of chondrocytes transfected with GFP-Cyt.c after treatment with 13 nm AuNPs for 8 h. Original magnification: ×400. e Confocal imaging of chondrocytes stained with Mitotracker Red 633 after treatment with 3, 13, and 45 nm AuNPs, respectively, for 8 h. Scale bar 20 μm