Radiotracer methods and neutron activation analysis for the investigation of nanoparticle biokinetics in living organisms

The physical foundations and methodological issues of nuclear activation methods (radiotracers and neutron activation analysis) have been discussed in regards to a study of assimilation of a number of inorganic nanoparticles (NPs) by living organisms and their distribution in organs and excretion. The methods of activation of NPs within a colloidal solution or biological samples have been analyzed. Advantages of the radioactive tracer method and neutron activation analysis have been compared. A brief overview of a number of successful works using nuclear methods for studying the interaction of silver, gold, selenium, and zinc and titanium oxide NPs with living organisms has been given. As an example, a description and results of the experiment on long-term (28 days) injection of silver NPs into laboratory mice have been given. The abilities of neutron activation analysis to estimate the mass of residual blood (and the NPs in it) in biological samples and to confirm the penetration of the NPs through the blood-brain barrier in quantitative terms have been demonstrated.