Fig. 4: Dark/photo-toxicity and homologous targeting in cells and penetration of tumor spheres.

a Dark and phototoxicity of 4T1 cells after different treatments. [NIR (-)] represented without 808 nm laser irradiation; [NIR (+)] represented with 808 nm laser irradiation. Data are given as means ± SD (n  =  5 biologically independent samples). Significant differences were evaluated by two-tailed unpaired t-test. b Fluorescence images of live/dead staining of 4T1 cells. The live cells were stained with AM (green) and the dead cells were stained with PI (red). Scale bar =100 μm c Homotypic targeting of ICG@CCM-AuNC-PO₂-Hb on co-cultured 4T1/ NIH3T3 cells (blue = nucleus, green = 4T1 cells membrane, red = ICG@CCM-AuNC-PO₂-Hb). (1) blank, (2) ICG@CCM-AuNC-PO₂-Hb and (3) ICG@CCM-AuNC-PO₂-Hb + NIR. Scale bar = 50 μm (left), scale bar = 10 μm (right). The images on the right represent enlargements of the numbers corresponding to the embedded boxes in the image on the left, respectively. d Flow cytometric images of 4T1, NIH3T3 and B16-F10 cells after incubation with ICG@CCM-AuNC-PO₂-Hb, followed by 808 nm laser irradiation for 1.5 min (0.5 W cm⁻²). e In vitro penetration of ICG@CCM-AuNC-PO₂-Hb after laser irradiation. Z-stack images using CLSM with thickness of 20 μm were obtained from the top to the equatorial plane of 3D 4T1/ NIH3T3 tumor spheroids. Scale bar = 100 μm. Experiments were performed three times (b–e), with similar results. Source data are provided as a Source Data file.