Uptake of Gold Nanoparticles in Several Rat Organs after Intraperitoneal Administration In Vivo: A Fluorescence Study

BACKGROUND The gold nanoparticles (GNPs) have potential applications in cancer diagnosis and therapy. In an attempt to characterise the potential toxicity or hazards of GNPs as a therapeutic or diagnostic tool, the fluorescence spectra in several rat organs in vivo were measured after intraperitoneal administration of GNPs. METHODS The experimental rats were divided into control and six groups (G1A, G1B, G2A, G2B, G3A, and G3B; G1: 20 nm; G2: 10 nm; G3: 50 nm; A: infusion of GNPs for 3 days; B: infusion of GNPs for 7 days). The fluorescence measurements were investigated in the liver, kidney, heart, and lung organs of rats after intraperitoneal administration of GNPs for periods of 3 and 7 days in vivo. RESULTS The 10 and 20 nm GNPs exhibited spherical morphology shape, while the 50 nm GNPs exhibited hexagonal shape. A sharp decrease in the fluorescence intensity induced with the larger 50 nm GNPs in the liver, kidney, heart, and lung organs of rats at the exposure duration of 3 and 7 days in vivo compared with the smaller 10 and 20 nm GNPs was observed. CONCLUSIONS The decrease in fluorescence intensity may be attributed to occurrence of strong quenching, decrease in number and surface area of GNPs, and high clearance of GNPs via urine and bile. Moreover, decreasing size may lead to an exponential increase in surface area relative to volume, thus making GNPs surface more reactive on aggregation and to its surrounding biological components. The size, shape, surface area, number, and clearance of GNPs play a key role in toxicity and accumulation in the different rat organs. This study demonstrates that fluorescence peak intensity is particle size and exposure duration dependent. This study suggests that fluorescence intensity can be used as a useful tool for pointing to bioaccumulation and toxicity induced by GNPs in the different rat organs.