Improving the methotrexate loading/release of magnetite by coating with silica of various thicknesses

Abstract

The stability of magnetite nanoparticles can be improved by coating with inert, biocompatible and non-toxic materials. The coated magnetite nanoparticles are the potential candidates for drug delivery, cancer treatment and MRI. In the present study, magnetite nanoparticles (MNPs) were synthesized by co-precipitation, while silica-coated magnetite nanoparticles (SMNPs) of various thicknesses were prepared by oil in water (o/w) microemulsion method. The concentration of sodium silicate (silica precursor) was taken in w/w with respect to MNPs. The size and shape of the MNPs and SMNPs were analyzed by field emission scanning electron microscopy (FESEM) equipped with an energy dispersive X-rays (EDX) spectroscopy, transmittance electron microscopy (TEM), X-rays diffraction (XRD) and dynamic light scattering (DLS). The surface functional groups were detected by using Fourier-transform infrared (FTIR) spectroscopy. The magnetic properties were measured in vibrating sample magnetometer (VSM) and a decrease in the magnetization was noted by increasing the thickness of silica coating around MNPs. Finally, the MNPs and SMNPs of various thicknesses were loaded with anticancer drug methotrexate (MTX) and the release study was monitored by dialysis method. The MNPs have shown a burst release of MTX whereas a sustained drug release was noted for SMNPs of various thicknesses. Among silica coated MNPs, 2 times silica-coated magnetite (2SMNPs) displayed a more sustained drug release. The work presented here therefore, describes a facile and convenient method to fabricate silica coated magnetite nanoparticles for the potential use in the drug delivery systems.