Synthesis and Biodistribution Study of Biocompatible 198Au Nanoparticles by use of Arabinoxylan as Reducing and Stabilizing Agent

Radioactive gold-198 is a useful diagnostic and therapeutic agent. Gold in the form of nanoparticles possesses even more exciting properties. This work aimed at arabinoxylan-mediated synthesis and biodistribution study of radioactive gold nanoparticles (198AuNPs). The particles were synthesized by mixing suspension of arabinoxylan with H198AuCl4 without use of any additional reducing and stabilizing agents. An aqueous suspension of arabinoxylan was added to a H198AuCl4 solution, which resulted in reduction of Au3+ to 198AuNPs. Biodistribution was studied in vitro and in rabbit. The particles having exceptional stability were readily formed. Highest radioactivity was recorded in spleen after 3 h followed by liver, heart, kidney, and lungs after i.v. administration. After 24 h, the activity was not detectable in the spleen; it accumulated in the liver. However, after oral administration, the activity mainly accumulated in the colon. In serum proteins, the distribution was α1-globulin 6.5%, α2-globulin ~ 2%, β-globulin ~ 1%, γ-globulin 0.7%, and albumin 0.7% of the administered dose. This indicates a low protein binding implying high bioavailability of the particles. The cytotoxicity study showed that the particles were inactive against HeLa cell line and Agrobacteriumtumefaciens. Highly stable 198AuNPs reported in this work have the potential for targeting the colon. They show affinity for globulins, the property that can be used in the study of the immune system.