Preparation of degradable magnetic temperature- and redox-responsive polymeric/Fe3O4 nanocomposite nanogels in inverse miniemulsions for loading and release of 5-fluorouracil

This work reports the synthesis of novel degradable magnetic temperature- and redox-responsive polymer/Fe3O4 nanocomposite nanogels (NCGs) through inverse miniemulsion polymerization and their potential application as nanocarriers for controlled drug delivery. Surface of Fe3O4 magnetic nanoparticles (MNPs) were vinyl-modified with 2-isocyanatoethyl methacrylate. Poly(N-vinylcaprolactam) (PNVCL)/Fe3O4 NCGs were prepared via inverse miniemulsion polymerization by using a disulfide-containing cross-linker. The Fe3O4 MNPs were chemically attached to the polymer matrix of NCGs, offering a good structural integrity of NCGs in aqueous systems. The PNVCL/Fe3O4 NCGs not only inherited the good superparamagnetism of Fe3O4 MNPs, but also displayed a reversible temperature-responsiveness as well as marked redox-responsiveness. The release behavior of a model anticancer drug 5-fluorouracil from the PNVCL/Fe3O4 NCGs could be conveniently tuned by the external temperature, redox condition of media, or their combination. The prepared PNVCL/Fe3O4 NCGs displayed a low cytotoxicity, holding a great potential in functioning as magnetic guiding nanocarriers for controlled drug delivery.