Facile preparation of magnetic nanocrystals using amphiphilic hyperbranched polymers as unimolecular nanoreactors and magnetofection in vitro

A new strategy for the preparation of Fe3O4 nanocrystals (NCs) and FePt bimetal NCs with amphiphilic hyperbranched polymers as unimolecular nanoreactors has been described. The amphiphilic hyperbranched polymers were synthesized by grafting methyl acrylate to hyperbranched poly(ethylenimine)s (HPEI) with the help of Michael addition reaction. The hydrophilic HPEI core was used to stabilize the magnetic NCs, whereas the hydrophobic methyl ester terminals can prevent the aggregation of polymers and NCs, thus magnetic NCs with a narrow size distribution were prepared. The resulting Fe3O4 NC/amphiphilic hyperbranched polymer nanocomposites also showed slightly better magnetofection property than HPEI transfection and their luciferase expression level in maximum was 1.3-fold greater than that for HPEI transfection. (C) 2014 Society of Plastics Engineers