Development of Nanoclusters Using Tannic Acid-Coated Ultra-Small Iron Oxide Nanoparticles for Simultaneous MRI Imaging and Drug Delivery

Iron oxide nanoparticles are generally believed safe and effective magnetic resonance imaging (MRI) contrast agents and are in clinical use for iron deficiency treatment. We have shown that ultra-small nanoparticles (USNPs, < 4 nm) are great positive (T₁) contrast agents, the clinically preferred type. However, these extremely small nanoparticles experience fast renal clearance, limiting their use in therapy tracking. Here, we are forming nanoclusters by crosslinking individual small nanoparticles in order to increase the size, which subsequently improves their circulation times. In this presentation, we will discuss the method of synthesizing the ultra-small nanoparticles, surface functionalization of the nanoparticles, and the formation of the nanoclusters. The nanoclusters will be characterized by size, size distribution, and relaxivity. Bovine serum albumin (BSA) and tannic acid interactions will facilitate the formation nanoclusters and the procedure can be modified to tailor the size of the nanoclusters. The clusters were successfully formed within the desired size range with T₁ character.