Functionalized multimodal ZnO@Gd 2 O 3 nanosystems to use as perspective contrast agent for MRI

The main aim of this research was the synthesis of the multimodal hybrid ZnO@Gd 2 O 3 nanostructures as prospective contrast agent for Magnetic Resonance Imaging (MRI) for bio-medical applications. The nanoparticles surface was functionalized by organosilicon compounds (OSC) then, by folic acid (FA) as targeting agent and doxorubicin (Dox) as chemotherapeutic agent. Doxorubicin and folic acid were attached to the nanoparticles surface by amino groups as well as due to attractive physical interactions. The morphology and crystallography of the nanostructures were studied by HRTEM and SAXS techniques. After ZnO nanoparticles surface modification by Gd 3+ and annealing at 900 °C, ZnO@Gd 2 O 3 nanostructures are polydispersed with size 30–100 nm. NMR (Nuclear Magnetic Resonance) studies of ZnO@Gd 2 O 3 were performed on fractionated particles with size up to 50 nm. Fourier transform infrared spectroscopy (FTIR), UV–vis spectroscopy, zeta-potential measurements and energy dispersive X-ray analysis (EDX) showed that functional groups have been effectively bonded onto the nanoparticles surface. The high adsorption capacity of folic acid (up to 20%) and doxorubicin (up to 40%) on nanoparticles was reached upon 15 min of adsorption process in a temperature-dependent manner. The nuclear magnetic resonance (NMR) relaxation measurements confirmed that the obtained ZnO@Gd 2 O 3 nanostructures could be good contrast agents, useful for magnetic resonance imaging.