Fig. 3.

Tumour targeting and biodistribution of cRGD-MNPs using an MDA-MB-231 xenograft mouse model. a In vivo merged PA and US images of MDA-MB-231 tumour-bearing mice at different times (pre, 1, 2, 4 and 12 h) after intravenous injection of MNPs or cRGD-MNPs (100 μM, 200 μL). Scale bar: 2 mm. b Quantitative analysis of PA intensities of tumour sites at the different time points in a. c Tumour-to-background tissue ratios obtained at 2 h post-injection of MNPs or cRGD-MNPs. d The biodistribution of rhodamine-labelled MNPs or cRGD-MNPs in the heart, liver, spleen, lung, kidney and tumour from MDA-MB-231 tumour-bearing mice 2 h post-injection. e Quantitative analysis of the fluorescence intensities of the tissues in (d). Data are presented as the mean ± SD (n = 3); ***p < 0.001, *p < 0.05