Fig. 7

Engineering of a neutrophil-targeting self-luminescent nanoprobe for imaging of pulmonary micrometastasis in mice. A A scheme illustrating the synthesis of PGP peptide-conjugated DSPE-PEG (DSPE-PEG-PGP) capable of targeting neutrophils by binding to the CXCR2 receptor. B A sketch showing preparation of the neutrophil-targeting nanoprobe (LAD-PGP NPs). C, D A typical TEM image (C) and size distribution (D) of LAD-PGP NPs. E Fluorescence microscopic images of neutrophils at 1 h after incubation with the same dose of LAD NPs, LAD-PEG NPs, or LAD-PGP NPs. Nuclei were labeled with DAPI (blue). Scale bars, 20 μm. F, G Typical flow cytometry profiles (F) and quantitative data (G) of fluorescence intensities in neutrophils after 1 h of incubation with different NPs. H Luminescence images (left) and quantitative analysis (right) of PMA-stimulated neutrophils after treatment with different NPs. I Ex vivo fluorescence images (left) and quantified intensities (right) showing the accumulation of three NPs in lung tissues of mice at week 3 after i.v. inoculation of 4T1-GFP cells. Diseased mice injected with PBS served as a control. J Immunofluorescence images of lung tissue sections of healthy mice and diseased mice at week 3 after inoculation of 4T1-GFP cells. Lung tissues were isolated for analyses at 12 h after i.v. injection of 3 mg LAD-PGP NPs in each mouse. K, L Comparison of in vivo luminescence intensities in lung tissues after i.v. injection of 3 mg different nanoprobes in mice at week 3 after inoculation of 4T1-GFP cells. K Representative in vivo luminescence images. L Quantitative analysis of luminescence intensities. Data are expressed as means ± SD (G, I, L, n = 4; H, n = 3). *P < 0.05, **P < 0.01, ***P < 0.001