Synthesis and characterization of PEG coated superparamagnetic iron oxide nanoparticles

In this study, superparamagnetic iron oxide nanoparticles (SPIONs) were synthesized by co-precipitation method and the parameters affecting the magnetic properties of the nanoparticles were investigated. Effective parameters were optimized to obtain SPIONs with high saturation magnetization. Then, the obtained SPIONs were coated with polyethylene glycol (PEG) and the magnetic properties of PEG-coated SPIONs were investigated. Firstly, co-precipitation parameters were changed and their effects on the properties of the nanoparticles were investigated. The determined effective parameters, synthesis temperature and base concentration, were optimized and SPIONs with the highest saturation magnetization were obtained. The saturation magnetization value of the optimum SPIONs was measured as 67.9 emu/g and the particle size was calculated as 10.1±2.2 nm. Then, the optimum SPIONs were coated with polyethylene glycol (PEG) using mechanical stirring and ultrasonic bath and their magnetic properties were investigated. With mechanical stirring, 2.8 % coating was obtained for optimum SPIONs and 1.3 % increase in saturation magnetization value (68.8 emu/g) was observed. The particle size of PEG coated SPIONs obtained with mechanical stirring was calculated to be 11.0±2.6 nm. In the coating process performed by using ultrasonic bath, 4.0 % coating was obtained and 6.6 % increase in saturation magnetization value (72.4 emu/g) was observed. The particle size of PEG coated SPIONs obtained using ultrasonic bath was 10.9±2.9 nm. The uncoated and PEG coated SPIONs with high saturation magnetization value obtained in this study may have the potential to be used in various applications such as wastewater treatment, magnetic separation, biosensor.