LAUSR

The goal of this project was to fabricate a diagnostic system based on polyethylenimine (PEI) coated superparamagnetic iron oxide nanoparticles (Fe3O4 NPs) containing curcumin (CUR) in order to appraise the influence of CUR on increase of r2 relaxation rate of a negative contrast agent in magnetic resonance imaging (MRI). Based on the obtained results, the structural properties of the final product (i.e., Fe3O4-PEI-CUR NPs) were validated according to the initial hypothesis (i.e., NPs of about 50 nm in diameter with proper magnetic properties). Also, the CUR to Fe3O4-PEI NPs weight ratio of 2:1 was determined as an optimal ratio resulting in an 8% increase in the amount of loaded CUR as compared to the weight ratio of 1:1. In addition, CUR release from Fe3O4-PEI-CUR NPs was evaluated at two pH of 5.5 and 7.4 which revealed that the CUR release mechanism was pH-sensitive. The visual and numerical data of in vitro MRI all suggested an increase in negative contrast in the presence of CUR, as the r2 values for Fe3O4-PEI, Fe3O4-PEI-CUR (30% CUR loading), and Fe3O4-PEI-CUR (38% CUR loading) NPs were determined 78.278, 93.854, and 95.685 (1/mM sec), respectively. It was also shown that an 8% increase of CUR content in Fe3O4-PEI-CUR (38%) NPs merely led to a 2% increase in r2 and therefore in negative contrast. This result suggested that increasing CUR content more than a specific amount could not improve contrast considerably, while there was a significant difference (about 20%) between r2 values of Fe3O4-PEI and Fe3O4-PEI-CUR (30%) NPs.