CT monitoring of the
biodistribution. (A) Plot of HU versus Au concentration
collected on phantoms containing the Au(50)Fe(50)
NPs at variable dilution. CT images of phantoms’ cross-section
are also reported. (B, C) Comparative biodistribution study of Au(50)Fe(50)
and pure Au NPs administered on healthy mice and monitored by CT up
to 78 days. Top: Images of mouse spleen showing the evolution of contrast
over time, where it is appreciable that Au(50)Fe(50) NPs massively
leave the spleen after 78 days, while Au NPs persisted to a large
extent. Bottom: Plot of the relative increment of CT contrast over
time, measured as ΔHU (%), in the liver, spleen, and kidneys.
The biodistribution curve of Au(50)Fe(50) NPs exhibits a peak, while
the curve of Au NPs shows a step, except for kidneys, which are not
affected by Au distribution after 60 days. (D) Plot of ΔHU for
liver, spleen, kidneys, and bladder at 78 days after administration,
suggesting the flow of Au(50)Fe(50) NPs through the renal clearance
pathway, in contrast to the persistence of Au NPs in the liver and
spleen.