Thesis (Ph.D.) - Cairo University - Faculty of Science - Department of Analytical Chemistry

Magnetite nanoparticles constitute a class of nanoparticles which is easily manipulated using a magnetic field. In this work, Magnetite nanoparticles doped with ruthenium (Ru) ions [RuxFe(3-x)O₄] were synthesized via co-precipitation method where 0.0 {u2264} x {u2264} 0.5 with step 0.1. Also magnetite nanoparticles were doped with different concentrations of silver (Ag) ions Fe²⁺AgxFe₂³₋x/₃ O₄ and incorporated into the electro spun nanofibrous {u025B}-polycaprolactone (PCL) scaffolds for their use as wound dressings. Combined photoelectron spectroscopic and diffractometric studies demonstrated that Ru and Ag were incorporated in the magnetite lattice in form of cations, without forming any metallic clusters. The accommodation of Ag and Ru ions expanded the unit cell and lowered the crystallinity of the magnetite phase; which increased the concentration of topological irregularities and inhibited agglomeration. Amorphization of the structure led to its expansion in the bulk and contraction accompanied by a broadened distribution of Fe-O coordination on the surface. Ru ions were incorporated successfully into a magnetite structure with a slight influence on the value of the lattice parameter which increased from 8.354 Å at x = 0.0 to be 8.403 Å at x = 0.3; while crystallite size deteriorated from 20.1 nm at x = 0.0 to be around 3 nm at x = 0.3. In addition, surface roughness average was influenced by the dopant content, where it decreased from 35.6 nm at the pure magnetite to be 25.87 nm at x = 0.3. The ICP examination indicated that measured contents of Ru ions through competitions were around 41 ppm and increased to 190 ppm comparing with 43 and 199 ppm as a theoretical values both at x = 0.1 and at x = 0.5 respectively. Regarding magnetic properties; the coercivity raise from 40.11 Oe and raised 44.66 Oe for x = 0.0 and 0.5, respectively

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