| Magnetic nanoparticles (MNPs) have been successfully applied to the field ofclinical medicine as a new contrast agent for magnetic resonance imaging (MRI) dueto their proper paramagnetic and excellent biocompatibility. Thanks to theirmagnetocaloric effect in the external alternating magnetic field, MNPs has apromising future as the medium of tumor hyperthermia, especially for the localimplantation treatment. However, there are still some limitations on the MNPs’application as nanocarriers in magnetic targeting drug delivery system for systemictherapy. Therefore, it is extremely siginificant to develop a kind of MNPs with highdrug loading efficiency, long circulation time, good dispersion and stability as acarrier of anticancer drugs in the systemic therapy.In this research, MNPs (Fe3O4-SiO2-PLA-MPEG) with three different SiO2coating thicknesses were prepared, in which, Fe3O4is designed as the magnetic core,SiO2is the core coating, the amphiphilic polymer of polylactic acid-co-methoxypolyethylene glycol (PLA-MPEG) is the shell. The SiO2coating can increase thesurface area of the magnetic core and protect it. Hydrophobic anticancer drugs can beloaded in PLA segment due to the hydrophobic effect. MPEG segment can improvewater-dispersity of MNPs, and extend the circulation time in vivo. The inorganic coreand organic shell are connected by3-aminopropyltrimethoxysilane (APS), which isused as the chemical bridge.The prepared MNPs were characterized by transmission electron microscopy(TEM), X-ray diffraction (XRD), vibrating sample magnetometer (VSM), inductivelycoupled plasma atomic emission spectrometry (ICP-AES), et al. The Fe3O4core wasdetermined as face-centered cubic crystal and paramagnetism. The MNPs arespherical, whose size increases with the thickness of the SiO2coating, and the meansize of nanoparticles is about200nm with a narrow size distribution. The graftquantity and density of the polymer on the surface of magnetic cores are bothincreased with the increase of the thickness of SiO2coating. The results of thehemolysis tests showed that the MNPs had a good biocompatibility withouterythrocyte agglutination and hemolysis phenomenon. Paclitaxel (PTX) was used as the model drug to study the drug loading andrelease behavior of MNPs. The drug loading results showed that the presence of SiO2coating could significantly improve the drug loading of PTX, the highest drug loadingwas up to7.18%, and was much larger than that of the control group (1.68%). Thedrug release results showed that the MNPs could provide the sustained release ofdrug.These results indicate that Fe3O4-SiO2-PLA-MPEG would be a suitable carrierfor hydrophobic anticancer drugs in magnetic targeting drug delivery system and hasa good prospect of application in the malignant tumors treatment. |
