Biodistribution of 1.4-and 18-nm Gold Particles in Rats

An experiment was conducted to show that very small nanoparticles (NP) can be translocated through the air/blood barrier of the respiratory tract in significant amounts, whereas 18-nm particles are almost trapped in the lungs. Au55 (Ph2PC6H4SO3Na) 12Cl6 and Au NPs were synthesized. Both NPs were activated by neutron activation. These NPs were sealed in quartz tubes either in solid form or in aqueous suspensions and activated at a neutron flux of 10 14 cm-2s-1 at the research reactor of the Hahn-Meitner, Germany. The Np suspension was visually checked for precipitates, and also checked by examination of the UV absorption peak at 523 nm, prior to the administration to rats. The rats were sacrificed by exsanguinations under deep anesthesia through the prepared abdominal aorta 24h after NP administration. Subsequent cytotoxicity investigations with various human tumor cell lines indicated that the cytotoxicity of this compound is unexpectedly high.