Sterilization on dextran-coated iron oxide nanoparticles: Effects of autoclaving, filtration, UV irradiation, and ethanol treatment

Dextran-coated magnetic iron oxide nanoparticles (DMNPs) have attracted significant attention for their many applications in biomedical area such as diagnostic magnetic resonance imaging (MRI), and gene therapy. For biomedical applications, nanoparticles must be sterile, and several terminal sterilization methods can be used. However, very little is known regarding the effect of sterilization methods on the properties of DMNPs. It is crucial to find out whether the DMNPs are affected by the sterilization process. This paper reported the influences on the physicochemical properties of DMNPs from four different methods: autoclaving, sterile filtration, UV irradiation and chemical sterilization with ethanol. In addition, cell viability was also studied. Our results indicate that filter sterilization changes the iron oxide/dextran ratio in DMNPs sample significantly. Besides, the autoclaving and ethanol treatment affected the polydispersity index of DMNPs sample. Thus, caution must be taken when choosing an appropriate method to perform sterilization for DMNPs.