Absorption optical density as a diagnostic tool for indicating the toxicity of gold nanoparticles
Nanotechnology has recently emerged as a promising approach for treatment and diagnosis of a variety of diseases. The aim of this study was to evaluate the blood absorption spectra to assess bioaccumulation and toxic effects of 100 μl of 10 and 50 nm gold nanoparticles (GNPs) upon intraperitoneal administration in rats for periods of three and seven days. Healthy 30 male Wistar-Kyoto rats were individually caged and divided into control group (NG: n = 10), group 1 (A: infusion of 10 nm GNPs for three days; n = 5; B: infusion of 10 nm GNPs for seven days; n = 5) and group 2 (A: infusion of 50 nm GNPs for three days; n = 5; B: infusion of 50 nm GNPs for seven days; n = 5). Dose of 100 μl of 10 and 50 nm GNPs were administered intraperitonealy to the animals. The blood absorbance peaks for G1A, G1B, G2A and G2B significantly decreased compared with the control. The blood absorbance peaks for G1A significantly decreased compared with G1B; and G2A significantly decreased compared with G2B. This implies that G1A is highly reactive than G1B, and G2A is highly reactive than G2B. A significant decrease (p<0.05) in all blood absorbance peaks observed by the administration of 10 and 50 nm GNPs for periods of three and seven days compared with the control. For the same GNPs size, the accumulation of GNPs in the blood after the administration of GNPs for three days was greater than that for seven days. In addition to non-significant blood absorbance peak differences were observed with the different GNP sizes for the same period of administration of GNPs. This study suggests that the 10 nm GNPs are mostly up taken and accumulated by tissues which support the toxic effects of the smaller GNPs by tissues. However, the 50 nm GNPs are and highly accumulated in blood, suggesting the toxic effects of the larger GNPs by blood. Thus, the absorption optical density can be considered as a diagnostic tool indicating the bioaccumulation and toxicity effects of GNPs in the tissues of rats.
Key words: Gold nanoparticles, UV-visible spectroscopy, toxicity, histology.