Synthesis And Functionalization Research Of Polymer-Modified Iron-Oxide Nanoparticles

Due to the superparamagnetism and facile synthesis, iron-oxide nanoparticles haveattracted great interests from worldwide researchers. By surface modification usingpolymers, the dispersivity can be changed, and the nanoparticles can obtain theproperties of polymers, such as biocompatibility and sensitivity. Furthermore, polymerscan supply reaction sites for further modification and functionalization. This papercarried on a systematic research on the approaches of polymer modification at thesurface of iron-oxide nanoparticles. On this basis, we induced some functional groupsonto the surface for the production of novel multifunctional magnetic materials, whichmay develop new applications.We synthesized polymer-modified iron-oxide nanoparticles by “graft from”,”graftto”, and”graft through” strategy, using ROP, RAFT and traditional free radicalpolymerization. The resulted nanoparticles were studied and characterized detailed byIR, TEM, VSM, and TGA. Then, we selected suitable functional molecules according toapplication needs, and linked them onto the surface of nanoparticles by the reactionswith the groups at the end of polymer chains or side chains. Finally, we explored thefunctions and applications of these multifunctional magnetic nanomaterials.We first reported the successful synthesis of maltose-modified magneticnanoparticles. Such nanoparticles can be used as magnetic support for separation,purification and immobilization of the fusion enzyme of maltose binding protein andHeparinase I (MBP-HepA), and simplify the process of industrial production for lowmolecular weight heparin. The maltose-modified magnetic nanoparticles demonstratedfollowing advantages: high selectivity for the immobilization of MBP-HepA; highMBP-HepA adsorption capability; facile and rapid separation; well-maintainedenzymatic activity; improved thermal stability compared with free enzyme; andrepeated recyclability. Further, maltose-modified magnetic nanoparticles should be ableto be used for separation and immobilization of other MBP fusion enzymes, whichimplies wide application of such nanoparticles.