Microwave assisted polyol process for time-saving synthesis of superparamagnetic nanoparticles and application in artificial mimic enzyme

A microwave assisted polyol process accomplished within 10 min was developed for synthesis of superparamagnetic Fe3O4 nanoparticles (MNPs) with well controlled size between 2 and 6 nm. Effects of reaction time and temperature on the size of the MNPs were investigated through transmission electronic microscope, x-ray diffraction pattern, thermogravimetic and magnetic analysis. The results indicates that longer reaction time or higher temperature lead to formation of MNPs with larger size. As a proof-of-concept, the MNPs were utilized as peroxidase and their activity was also investigated. Oxidation of typical substrate, 3, 3', 5, 5' -tetramethylbenzidine, can be proceeded by using the MNPs as artificial mimic enzyme. The MNPs display the maximal catalyzed activity under the optimum condition as pH = 3.5, 40 °C and concentration of TMB and H2O2 with 120 and 110 mmol·l−1, respectively. This work provides a new way for fast synthesis of MNPs, which are of potential application in artificial mimic enzyme.