Synthesis and characterization of gadolinium nanosheets with bound rose bengal: potential use in photodynamic therapy and MRI

Gadolinium (Gd) is a trivalent paramagnetic element, making it useful as a contrast agent for magnetic resonance imaging (MRI). Gd-2(OH)(5)NO3-xH2O belongs to a new family of nanosheets. The advantages of these materials are their relatively small size, paramagnetic behavior, stability, lack of toxicity and highly ordered structure. In the present study, Gd-2(OH)(5)NO3 nanosheets were functionalized with amino groups and modified with the photosensitiser rose bengal (RB). This surface modification makes possible the use of the nanosheets in photodynamic therapy. The coated nanosheets were characterized with X-ray diffraction, fourier transform infrared spectroscopy and UV-Vis spectroscopy, as well as transmission electron microscopy. The possibility of using these nanosheets as potential spin-lattice (T-1) and spin-spin relaxation (T-2) contrast agents in MRI was evaluated at 1.5 T. Finally, the ability of Gd-2(OH)(5)NO3-RB to catalyze photooxidization reactions was examined using nuclear magnetic resonance (H-1 NMR) and gas chromatography-mass spectrometry (GC/MS).