title: Alterations in Gold Nanoparticle Levels Are Size Dependent, with the Smaller Ones Inducing the Most Toxic Effects and Related to the Time of Exposure of the Gold Nanoparticles.
abstract: BACKGROUND
  Gold nanoparticle (GNP) levels in the blood of ratsin vivohave not been previously documented. This study aimed to evaluate the influence of size and exposure duration of GNPs on the gold levels in the blood of ratsin vivo.
  
  
  METHODS
  Thirty rats were divided into five groups, NG = control group, G1A: infusion of 10 nm GNPs for three days, G1B: 10 nm GNPs for seven days, G2A: 50 nm GNPs for three days and G2B: 50 nm GNPs for seven days. Fifty microlitres of GNPs dissolved in aqueous solution were administered intraperitoneally every day for three and seven days. Gold concentrations in different samples were measured using inductively coupled plasma-optical emission spectrometer (ICP-OES).
  
  
  RESULTS
  The percentage normalized value of 50nm GNPs increased in the blood of rats in both three and seven days when compared with 10 nm GNPs.
  
  
  CONCLUSIONS
  It became evident from the results of this study that the alterations in GNP levels were size dependent, with the smaller ones inducing the most toxic effects and related to the time of exposure of GNPs. The results might indicate that the smaller GNPs are mostly taken up and accumulate in the different rat organs, suggesting their toxic effects, while the 50 nm GNPs are retained in the blood of rats for a long time. These conclusions are further supported by the histological investigation.
authors.affiliation: Department of Physics and Astronomy, College of Science, King Saud University, Saudi Arabia. E-mail: abdelhalimmak@yahoo.com; mabdulhleem@ksu.edu.sa.
authors.forename: Mak
authors.initials: M
authors.lastname: Abdelhalim
keywords: Blood of rats; cancer; exposure duration; gold nanoparticles; in vivo