Figure 5: In vivo tumour targeting.

Epf images of (a) mice bearing MCF-7 xenografts and (b) averaged Epf intensity of the tumour ROI are shown, acquired 5, 24, 48 or 96 h after exposure to 5NP-1Tz and 5NP-2Tz labelled with AF660. The colour scales in a indicate fluorescence expressed as radiant efficiency ((p s⁻¹ cm⁻² sr⁻¹) (μW cm⁻²)⁻¹), where p s⁻¹ cm⁻² sr⁻¹ is the number of photons per second that leave a square centimetre of tissue and radiate into a solid angle of one steradian (sr). The scale extends from the following minimum–maximum values (left to right, top to bottom): 4.94 × 10⁷–6.03 × 10⁷; 1.19 × 10⁸–1.50 × 10⁸; 8.45 × 10⁷–1.01 × 10⁸; and 1.30 × 10⁸–1.80 × 10⁸. In the control mouse no injection was performed. Averaged Epf intensity of (c) tumour ROI and (d) isolated tumours are shown, acquired 5 or 48 h after exposure to non-functionalized 12 (12NP) or 20 nm (20NP) NPs, or to 5NP-1Tz and 5NP-2Tz or 5NP-1IgG and 5NP-2IgG, labelled with AF660. In e, fluorescence intensities (FIs) of tumour homogenates are displayed. Epf and FI values were normalized to the FI of injected solution to keep into account the differences in intrinsic fluorescence emission for each NP-antibody conjugate. Mean value±s.e. of three different samples for each experimental condition are provided. *P<0.05, **P<0.01 and ***P<0.001 versus 5 h; ^§P<0.01 and ^§§P<0.001 versus 5NP-1Tz (Student’s t-test). ND, non-detectable.