Preparation and characterization of carboxyl functionalization of chitosan derivative magnetic nanoparticles

The functionalized magnetic Fe3O4-chitosan derivative nanoparticles have been prepared by the covalent binding of alpha-ketoglutaric acid chitosan (KCTS) onto the surface of Fe3O4 magnetic nanoparticles via carbodiimide activation. Transmission electron microscopy (TEM) showed that the KCTS-bound Fe3O4 nanoparticles were regular spheres with a mean diameter of 26 nm. X-ray diffraction (XRD) patterns indicated that the Fe3O4 nanoparticles were pure Fe3O4 with a spinel structure, and the binding of KCTS did not result in a phase change. The binding of KCTS to the Fe3O4 nanoparticles was also demonstrated by the measurement of thermogravimetric analysis (TGA), differential scanning calorimetry analysis (DSC) and Fourier transform infrared (FTIR) spectra. Magnetic measurement revealed that the saturated magnetization of the KCTS-bound Fe3O4 nanoparticles reached 24.8 emu g−1 and the nanoparticles showed the characteristics of superparamagnetism.