In vivo SPECT imaging of tumors by 198,199Au-labeled graphene oxide nanostructures

Abstract

Graphene oxide (GO) sheets functionalized by aminopropylsilyl groups (8.0wt.%) were labeled by 198,199Au nanoparticle radioisotopes (obtained through reduction of HAuCl4 in sodium citrate solution followed by thermal neutron irradiation) for fast in vivo targeting and SPECT imaging (high purity germanium-spectrometry) of tumors. Using instant thin layer chromatography method, the physicochemical properties of the amino-functionalized GO sheets labeled by 198,199Au NPs (198,199Au@AF-GO) were found to be highly stable enough in organic phases, e.g. a human serum, to be reliably used in bioapplications. In vivo biodistribution of the 198,199Au@AF-GO composite was investigated in rats bearing fibrosarcoma tumor after various post-injection periods of time. The 198,199Au@AF-GO nanostructure exhibited a rapid as well as high tumor uptake (with uptake ratio of tumor to muscle of 167 after 4h intravenous injection) that resulted in an efficient tumor targeting/imaging. Meantime, the low lipophilicity of the 198,199Au@AF-GO caused to its fast excretion (~24h) throughout the body by the kidneys (as also confirmed by the urinary tract). Because of the short half-life of 198,199Au radioisotopes, the 198,199Au@AF-GO with an excellent tumor targeting/imaging and fast washing out from the body can be suggested as one of the most effective and promising nanomaterials in nanotechnology-based cancer diagnosis and therapy.