An Effort on Homogenizing Size Distribution of Magnetic Nanosphere Fe3O4-Poly-Lactic Acid for Hyperthermia Treatment

An effort on homogenizing the size distribution of magnetic nanosphere (MN) base on Fe3O4 nanoparticle coated by Poly-lactic acids (PLA) has been carried out. MN synthesis parameters were optimized to obtain MN with narrow size distribution, but still maintaining other properties especially its magnetic property. The synthesis process was then followed by sequential centrifugation with different speed for selective separation of MN with different size distribution. The size distribution characteristics of the MN were evaluated by Scanning Electron Microscope (SEM), Transmission Electron Microscope (TEM), and Particle Size Analyzer (PSA). As a result, fractional MNs having different size distribution smaller than 400 nm were successfully obtained. The highest fraction was achieved for MN with size distribution < 150 nm, which was almost reaching 73% of total weight. However, the colloidal stability was still rather poor due to agglomeration tendency of MN which was observed clearly in its SEM and TEM images. The magnetic properties were analyzed by Vibrating Sample Magnetometer (VSM), which gave the saturation magnetization (Ms values). These values were slightly affected by the MN size distributions with maximum Ms value of 15.3 emu/g. Considering the composition used within the experiment and from the Ms values, the Fe3O4 nanoparticle loading efficiency of around 78.9% could be determined. Referring to these results, the colloidal stability problem could be overcome by co-polymer grafting on PLA surface, hence the MN could be expected to be applied for magnetic hyperthermia based therapy.