In vivo bio-distribution of intravenously injected Tc-99m labeled ferrite nanoparticles bounded with biocompatible medicals

Superparamagnetic nanoparticles have been widely utilized for in vivo or in vitro biomedical applications. Knowledge on the distribution of injected particles in organs is necessary to gain access to diagnosis or therapeutics. Thus, an in vivo study on the bio-distribution of the directly Tc-99m-labeled ferrite nanoparticles which were intravenously injected into tail vein of Wistar rats is performed. The dynamic bio-distribution was monitored by gamma camera. The scintigrams show that the injected dose are taken up by liver and lung. From dynamic scintigraphic image, it is observed that the uptake of particles by the organ is very fast and completed within first few minutes after intravenous injection. To investigate to what extent the Tc-99m labeled ferrite beads can be further conjugated with therapeutic drug, poly(ethylene glycol) (PEG) and two types of herb medicines, i.e. the Gentiana comnination and Trionyx sinensis with a function for chronic hepatitis, were sequentially conjugated with the ferrite adio-beads. It is demonstrated that the relative radioactivity of liver compared to that by lung and heart is lowered by the PEG modification. We also have performed in vivo study by applying the commercially available Nd-Fe-B magnet onto the site before intravenous injection into rat. The result implies that the directly Tc-99m labeled ferrite nanoparticles, conjugated with biocompatible medicals, may implicate for diagnostic and therapeutic applications.