Magnetic nanoparticles assembly on peptide nanotube

In this report a novel nanostructured magnetic assembly that consists of magnetic nanoparticles coated on peptide nanotubes (MPN) is presented. Specifically, MPN samples that consist of nanoparticles of different magnetic materials including bacteria-produced magnetite (Fe₃O₄) and nickel were examined. The bacterial magnetite nanoparticles can be coated inside or outside the peptide nanotubes depending on the synthesis condition. The structure and morphology of MPNs were examined by transmission electron microscopy (TEM) and the magnetic properties were characterized using a vibrating sample magnetometer (VSM). Results show that the assembled morphology and resulting magnetic behavior of Fe₃O₄ nanoparticles coated on the nanotubes depend on the synthesis condition and indeed vary with the concentration of the nanoparticles in the solution. The magnetic behavior clearly reflects the geometry of the magnetic particles. The magnetic properties of nickel nanoparticles mineralized and coated onto peptide nanotubes are governed by the particle size and crystallinity, controlled by the pH during the synthesis.