Multifunctional Core-Shell NiFe 2 O 4 Shield with TiO 2 /rGO Nanostructures for Biomedical and Environmental Applications.

Multifunctional core@shell nanoparticles have been synthesized in this paper through 3 stages: NiFe 2 O 4 nanoparticles by microwave irradiation using Pedalium murex leaf extract as a fuel, core@shell NiFe 2 O 4 @TiO 2 nanoparticles by sol-gel, and NiFe 2 O 4 @TiO 2 @rGO by sol-gel using preprepared reduced graphene oxide obtained by modified Hummer's method. XRD analysis confirmed the presence of both cubic NiFe 2 O 4 spinel and tetragonal TiO 2 rutile phases, while Raman spectroscopy analysis displays both D and G bands ( I D / I G  = 1.04) associated with rGO. Morphological observations by HRTEM reveal a core-shell nanostructure formed by NiFe 2 O 4 core as confirmed by SAED with subsequent thin layers of TiO 2 and rGO. Magnetic measurements show a ferromagnetic behavior, where the saturation magnetization drops drastically from 45 emu/g for NiFe 2 O 4 to 15 emu/g after TiO 2 and rGO nonmagnetic bilayers coating. The as-fabricated multifunctional core@shell nanostructures demonstrate tunable self-heating characteristics: rise of temperature and specific absorption rate in the range of Δ T  = 3-10°C and SAR = 3-58 W/g, respectively. This effectiveness is much close to the threshold temperature of hyperthermia (45°C), and the zones of inhibition show the better effective antibacterial activity of NTG against various Gram-positive and Gram-negative bacterial strains besides simultaneous good efficient, stable, and removable sonophotocatalyst toward the TC degradation.