Fig. 10. Analysis of in vivo fluorescence imaging for bio-responsive PEG NIR-AZA 1 (3.7 nmol) over time (n = 4). (a) Plot of TBR values at individual time-points over 96 h, dashed red line indicating threshold value of 2. Values determined by ROI total fluorescence signal of tumour divided by an averaged value of three independent background regions as measured by living image software v4.7. (b) Plot of tumour (solid trace) and averaged background (dashed trace) fluorescence intensity over 96 h. (c) Representative in vivo fluorescence images of 1 using a MDA-MB 231 subcutaneous tumour model at different time points (scale bar identical to Fig. 8 and 9). First image shows tumour ROI (solid circle) and three background ROIs (dashed circles).