T1-weighted and T2-weighted MRI probe based on Gd-DTPA surface conjugated SPIO nanomicelles

Herein we report novel gadolinium chelate surface conjugated superparamagnetic iron oxide (SPIO) nanomicelles. In our design, Gd-diethylenetriaminepentaacetic acid (Gd-DTPA) was conjugated with folic acid (FA) targeting the polyaspartic derivative (PASPD) coating surface of SPIO nanoparticles (IO-PASPD). The morphology of Gd-DTPA-IO-PASPD was uniformly spherical with an average particle size of 50 nm measured using dynamic light scattering (DLS) and transmission electron microscopy (TEM) imaging. The stability results showed that the FA-Gd-DTPA-IO-PASPD can stably preserve IO under physiological conditions (pH 7.4). An MTT assay showed that the cytotoxicity of FA-Gd-DTPA-IO-PASPD against hepatoma carcinoma (HepG2) cells was not significant after 24 h incubation. MRI in vitro and in vivo effects were also imaged and characterized. In summary, FA-Gd-DTPA-IO-PASPD could achieve T-1-weighted and T-2-weighted MR imaging simultaneously and lengthen the half life time.