Preparation and characterized of polyethylenimine-coated magnetic nanoparticles

In this paper, we prepared the magnetite nanoparticles coated with polyethlenimine, (CH2-CH2-NH)_n with the coprecipitation method. X-ray diffraction (XRD) and Transmission Electron Microscope (TEM) methods were used to analyze their phase and size; The groups adhered on the surface were observed by Fourier transform infrared spectroscopy(FTIR); adsorption rate of the PEI was got by thermogravimetric analysis(TG) and magnetic properties were measured by vibrating sample magnetometer(VSM). Both uncoated and PEI-coated magnetic particles exhibited the superparamagnetic behavior and strong saturation magnetization at room temperature, about 70 cmu/g. The PEI-coated magnetic nanoparticles can be used in the fields of medical biotechnology, such as gene detection and vector for magnetic guidance etc.