Study of structural and magnetic properties and heat induction of gadolinium-substituted manganese zinc ferrite nanoparticles for in vitro magnetic fluid hyperthermia.

This article outlines the synthesis of gadolinium (Gd)-doped manganese zinc ferrite magnetic nanoparticles (MNPs) as potential magnetic carriers for magnetic fluid hyperthermia (MFH). MNPs with high specific loss power (SLP; 146 W/g) have been developed and used for an in vitro hyperthermia study. The treatment of MFH is fruitful if there is an adequate number of MNPs in tumor cells with the highest SLP to rapidly generate heat while minimizing thermal injury to surrounding healthy tissue. X-ray diffraction patterns of the studied particles confirm the formation of a cubic spinel structure. Field emission scanning electron micrographs showed homogeneous distributions of particles with some agglomerates with a granular appearance. Transmission electron microscopy analysis showed the presence of agglomerated spherical particles at the surface. The substitution of Gd resulted in superparamagnetism at room temperature as confirmed by vibrating sample magnetometer analysis. The estimated saturation magnetization reduced from 48.6 to 28.2 emu/g with an increase in Gd concentration. However, the coercivity increased from 1093 Oe to 1597 Oe. Field cooled and zero field cooled measurements showed Curie temperatures from 315 to 326 K, as required for MFH applications. Cell viability measurements indicated that the MNPs are nontoxic to A549 cells for the studied concentrations of particle fraction and a contact time of up to 24 h. The interaction of the MNPs with A549 cells was highlighted from an image captured by an inverted microscope. In order to treat cancer in vivo, an in vitro hyperthermia study has initially been carried out with A549 cells.

Synthesis, characterization and biocompatibility of chitosan functionalized superparamagnetic nanoparticles for heat activated curing of cancer cells.

Surface functionalization, colloidal stability and biocompatibility of magnetic nanoparticles are crucial for their biological applications. Here, we report a synthetic approach for the direct preparation of superparamagnetic nanoparticles consisting of a perovskite LSMO core modified with a covalently linked chitosan shell that provides colloidal stability in aqueous solutions for cancer hyperthermia therapy. The characterization of the core-shell nanostructure using Fourier transform infrared spectroscopy; thermo-gravimetric analysis to assess the chemical bonding of chitosan to nanoparticles; field-emission scanning electron microscopy and transmission electron microscopy for its size and coating efficiency estimation; and magnetic measurement for their magnetization properties was performed. Zeta potential and light scattering studies of the core shell revealed it to possess good colloidal stability. Confocal microscopy and MTT assay are performed for qualitative and quantitative measurement of cell viability and biocompatibility. In depth cell morphology and biocompatibility is evaluated by using multiple-staining of different dyes. The magnetic@chitosan nanostructure system is found to be biocompatible up to 48 h with 80% cell viability. Finally, an in vitro cancer hyperthermia study is done on the MCF7 cell line. During in vitro hyperthermia treatment of cancer cells, cell viability is reduced upto 40% within 120 min with chitosan coated nanoparticles. Our results demonstrate that this simplified and facile synthesis strategy shows potential for designing a colloidal stable state and biocompatible core shell nanostructures for cancer hyperthermia therapy.

Structured superparamagnetic nanoparticles for high performance mediator of magnetic fluid hyperthermia: synthesis, colloidal stability and biocompatibility evaluation.

Core-shell structures with magnetic core and metal/polymer shell provide a new opportunity for constructing highly efficient mediator for magnetic fluid hyperthermia. Herein, a facile method is described for the synthesis of superparamagnetic LSMO@Pluronic F127 core-shell nanoparticles. Initially, the surface of the LSMO nanoparticles is functionalized with oleic acid and the polymeric shell formation is achieved through hydrophobic interactions with oleic acid. Each step is optimized to get good dispersion and less aggregation. This methodology results into core-shell formation, of average diameter less than 40 nm, which was stable under physiological conditions. After making a core-shell formulation, a significant increase of specific absorption rate (up to 300%) has been achieved with variation of the magnetization (<20%). Furthermore, this high heating capacity can be maintained in various simulated physiological conditions. The observed specific absorption rate is almost higher than Fe3O4. MTT assay is used to evaluate the toxicity of bare and core-shell MNPs. The mechanism of cell death by necrosis and apoptosis is studied with sequential staining of acridine orange and ethidium bromide using fluorescence and confocal microscopy. The present work reports a facile method for the synthesis of core-shell structure which significantly improves SAR and biocompatibility of bare LSMO MNPs, indicating potential application for hyperthermia.