Preparation and characterization of chitosan-capped radioactive gold nanoparticles: neutron irradiation impact on structural properties

Gold-198 nanoparticles (198AuNPs) can be engineered with precise size, shape, composition, surface chemistry, radioactivity and radionuclide purity for clinical applications in nuclear medicine. In the present work, chitosan-capped AuNPs were prepared by exposing HAuCl4 to acidic chitosan solution under appropriate conditions and then irradiated in Tehran Research Reactor (TRR). After that, UV–Vis spectroscopy, FTIR, SEM and DLS were used for irradiated and non-irradiated sample characterization. FTIR studies were performed for controlling radiation-induced degradation of AuNPs@chitosan. From these results, it is concluded that the chemical bonds and backbone structure of chitosan does not change after the irradiation in a neutron flux of 3 × 1012 n cm−2 s−1 for 30 min. The SEM photograph clearly indicated that gold nanoparticles were spherical with an average size of ~62 and 63 nm before and after neutron irradiation, respectively. So, there was no significant difference in the size of irradiated and non-irradiated nanoparticles. 198AuNPs@chitosan with high radionuclide purity produced using the epithermal neutron-capture reaction, 197Au (n, γ) 198Au, are especially useful for cancer treatment and imaging.