Figure 3: Biodistribution of NPs.
(a) Body distribution of dye-functionalised NPs with an infrared cargo (DY-635[NP](DY-780)) in an athymic Nude-Foxn1nu mouse bearing a MDA-MB-231 human breast cancer xenograft (‘T’) confirmed selective uptake and excretion via the hepatobiliary route as reflected in accumulation of the dye in the gall bladder (‘G’). (b,c) CD1 mice injected with the same NP and assessed by multispectral optoacoustic tomography acquiring image data from several wavelengths (690, 710, 750, 770, 780, 800, 810 and 850 nm, 4 frames/wavelength, 0.1 mm step size) over an abdominal area of 1.7 cm using a frequency of 54.55 kHz (scale bars 5 mm). (b) Sections through the upper abdomen are single-spectral that elucidate anatomical structures (left panel; ‘I’ intestines, ‘L’ liver, ‘V’ vertebral column, ‘M’ autochthonous back muscles and ‘A’ aorta) or processed multispectrally to visualise the dye cargo (DY-780) immediately prior to injection (0 min) or during early uptake (20–30 min after injection). Far right panel: Corresponding cryosection of the upper abdomen; ‘G’ indicates gall bladder containing the dye. (c) Subsequent sections through the lower abdomen processed for structural information (left panel; in addition the kidneys (‘K’) and spleen (‘S’) are visible) middle and right panels are processed to visualise the dye cargo. The IR dye is restricted to the upper abdomen and depicts liver and biliary tree.
