Synthesis and Characterization of PEGylated Magnetite Nanoparticles for Drug Delivery Applications

Magnetite nanoparticles (MNP) of about 10 nm were synthesized by an economic, biocompatible chemical co-precipitation of Fe2+ and Fe3+ in an ammonia solution. Synthetic methodology has been developed to get a well dispersed and homogeneous aqueous suspension of MNPs. Citric acid was used to stabilize the magnetite particle suspension, it was anchored on the surface of freshly prepared MNPs by direct addition method. Carboxylic acid terminal group not only render the particles more water dispersible but also provides a site for further surface modification. The surface modification of the particles is provided by polyethylene glycol (PEG). The naked MNPs are often insufficient for their stability, hydrophilicity and further functionalization. To overcome these limitations, citric acid was conjugated on the surface of the MNPs and PEG was covalently attached to carboxylic moieties of citric acid anchored MNPs by carbodiimide chemistry. The colloidal stability of MNPs in aqueous suspension was improved after the surface modification. The microstructure and morphology of the nanoparticles were characterized by X-ray diffraction (XRD) and transmission electron microscopy (TEM), and the interaction between citric acid and MNPs and citric acid and PEG were characterized by Fourier transform infrared spectroscopy (FTIR), whereas the magnetic properties were investigated by vibrating sample magnetometry (VSM). It was found that the nanoparticles demonstrated well defined superparamagnetic behavior.

Keywords:

Drug delivery , Magnetite nanoparticle , Citric acid , Polyethylene glycol (PEG