Synthesis, MR Relaxivities, and In Vitro Cytotoxicity of 3,5-Diiodo-L-tyrosine-Coated Gd₂O₃ Nanoparticles

In this study, we report the synthesis and characterization of 3,5-Diiodo-L-tyrosine (DLT)-coated gadolinium oxide (Gd₂O₃) nanoparticles. The bonding status of DLT-coated Gd₂O₃ nanoparticles (DLT-NPs) were confirmed by Fourier transform infrared (FT-IR) absorption spectra and thermogravimetric analysis (TGA). The surface coating amount was estimated to be 73% in weight percent from a TGA. High-resolution transmission electron microscope (HR-TEM) shows that DLT-NPs were spherical in shape with an average diameter 2 nm. The MR relaxivity measurements confirmed that the DLT-NPs have higher r₁ = 9.24 s-1 mM-1 than commercially available contrast agents. Furthermore, the bio-compatibility of the DLT-NPs were measured by cytotoxicity test, which has demonstrated that the cell viability reached up to 60% with Gd concentrations up to 50 μM for both DU145 and NCTC1469 cell lines, making them a promising candidate for biomedical applications.