Controlled Nanoparticle Formation by Enzymatic Deshelling of Biopolymer-Stabilized Nanosuspensions

The synthesis and characterization of iron oxide (magnetite), cobalt oxide, manganese oxide (hausmannite) nanoparticles, and mixed phase iron oxide, were reported. Mixed-valence oxide particles stabilized by the biopolymer dextran were prepared using alkali treatment and microwave heating of metal salt solutions. Stable suspensions of dextran-bound nanoparticles of the metal oxide were used to cast as flexible transparent films. Transmission electron microscopy (TEM) observation revealed that discrete nanoparticles were obtained with metal oxide complexes using dextran. Purified dextran-coated metal oxide suspensions were dried to produce transparent brown-colored films, while dextran and iron oxide-dextran composites were dried to produce brittle films. The study concluded that enzyme treated nanoparticle materials can be converted to carbon-coated nanoparticles for magnetic storage or as high surface area catalysts.