MnZnFe nanoparticles for self-controlled magnetic hyperthermia

Manganese zinc iron magnetic nanoparticles were synthesized by a co-precipitation method for application as hyperthermia inducing agents. The structure, morphology and magnetic properties of the nanoparticles are characterized using scanning electron microscopy, X-ray diffraction, and a superconducting quantum interference device. The magnetic properties being investigated include Curie temperature, saturation magnetization, remnant magnetization, coercive field, and hysteresis. The study showed that adjusting the Mn contribution to the particles contributed to the adjustment of all magnetic properties of the complex.     

In situ synthesis of cobalt ferrite nanoparticle/polymer hybrid from a mixed Fe–Co methacrylate for magnetic hyperthermia

Hyperthermic CoFe₂O₄ nanoparticle (CFO NP)/polymer hybrids were synthesized by hydrolysis–condensation from a complex of Co and Fe possessing methacrylate ligands. Single-crystal analysis revealed that the complex consisted of two Co and four Fe metal atoms coordinated by methacrylate and 2-methoxyethoxy groups. The complex was copolymerized with 2-hydroxyethyl methacrylate (HEMA) and the resulting copolymer was then hydrolyzed to form a CFO NP/copolymer of poly(methacrylate) and poly(2-hydroxyethyl methacrylate) hybrid. Copolymerization with HEMA enhanced the stability of the hybrid in water. The size and magnetic properties of CFO in the hybrid were controlled by adjusting the hydrolysis conditions. Moreover, the hybrid generated heat under an alternating current magnetic field; its exothermal properties depended on the magnetic properties of the hybrid, the strength of the applied field, and the CFO NP content in the agar phantom matrix.     

Study of carbon encapsulated iron oxide/iron carbide nanocomposite for hyperthermia

Magnetic nanocomposite has been synthesized successfully using biopolymer route which acts as a source of carbon for carbide formation. The present approach based on thermal decomposition represents a considerable advance over previous reports that often use high-energy procedures or costly and hazardous precursors. X-ray diffraction, high-resolution transmission electron microscopy and vibrating sample magnetometer have been used to characterize the composites. Multi phase formation is evident from X-ray diffraction in the as-prepared samples. Phase confirmation was further done from M (magnetization) versus T (temperature) curve indicating presence of different phases of carbide along with iron oxide. TEM study suggests formation of cuboidal shape nanocomposite using two different quenching conditions. Transmission electron microscopy also confirmed the formation of carbon layer in the vicinity of the Fe₃O₄/Fe₃C nanoparticles. The magnetic measurement shows that the composite nanoparticles exhibit a maximum magnetization of 60 emu g⁻¹ at room temperature. Biocompatibility study with three different cell lines (HeLa, MCF-7 and L929) confirms that these nanocomposites are biocompatible. Temperature versus time measurement in an AC field suggests good heating ability of the samples. These investigations indicate that these nanocomposites may be useful for bioapplications, in particular for hyperthermia.     

SAR CHARACTERIZATION OF FOCUSED PLANAR ARRAY OF WATER-LOADED MODIFIED BOX-HORNS FOR HYPERTHERMIA

A 4×4 planar array of modified box-horns as a microwave hyperthermia applicator is theoretically studied to characterize power deposition (SAR) in heating tissue (muscle) at 2450 MHz. A modified box-horn is a novel improved version of conventional box-horn in which horn exciting the box waveguide is flared in both E-and H-planes. Modified box-horn supports TE₁₀ and TE₃₀ modes. The amplitude distribution over the H-plane of the box-horn aperture is a closer approximation to the uniform distribution. It is proposed that the interior of the box-horn be filled with water to provide a better impedance match to biological tissue. By applying Fresnel-Kirchhoff scalar diffraction field theory, the expression for electric field in heating region is derived and distribution of specific absorption rate (SAR) in that region due to planar array of modified box-horns as direct contact applicator is evaluated at 2450 MHz. The results of modified box-horn array are compared with those of a single modified box-horn operating at the same frequency. Results demonstrate that planar array of modified box-horns offers improvement in SAR distribution and penetration depth. It is shown that by changing the phase and amplitude of excitation of the modified box-horns of the array, the relative amplitude and position of the hot spot can be changed. The present analysis is validated through the results obtained by plane wave spectral technique.     

Controlled assembly of superparamagnetic iron oxide nanoparticles on electrospun PU nanofibrous membrane: A novel heat-generating substrate for magnetic hyperthermia application

A facile method of fabricating novel heat-generating membranes composed of electrospun polyurethane (PU) nanofibers decorated with superparamagnetic iron oxide nanoparticles (NPs) is reported. Electrospinning was used to produce polymeric nanofibrous matrix, whereas polyol immersion technique allowed in situ assembly of well-dispersed Fe₃O₄ NPs on the nanofibrous membranes without any surfactant, and without sensitizing and stabilizing reagent. The assembly phenomena can be explained by the hydrogen-bonding interactions between the amide groups in the PU matrix and the hydroxyl groups capped on the surface of the Fe₃O₄ NPs. The prepared nanocomposite fibers showed acceptable magnetization value of 33.12 emu/g, after measuring the magnetic hysteresis loops using SQUID. Moreover, the inductive heating property of electrospun magnetic nanofibrous membranes under an alternating current (AC) magnetic field was investigated. We observed a progressive increase in the heating rate with the increase in the amount of magnetic Fe₃O₄ NPs in/on the membranes. The present electrospun magnetic nanofibrous membrane may be a potential candidate as a novel heat-generating substrate for localized hyperthermia cancer therapy.     

In vitro application of Fe/MgO nanoparticles as magnetically mediated hyperthermia agents for cancer treatment

In this work we study the heating efficiency of Fe/MgO magnetic core/biocompatible shell nanoparticles and their in vitro application in magnetic hyperthermia on cancer cells. Different human breast cancer cell lines were used to assess the suitability of nanoparticles for in vivo application. The experiments revealed a very good cytotoxicity profile and significant uptake efficiency together with relatively high specific absorption rates and fast thermal response, features that are crucial for adequate thermal efficiency and minimum duration of treatment.     

Biocompatibility of various ferrite nanoparticles evaluated by in vitro cytotoxicity assays using HeLa cells

Magnetic nanoparticles for thermotherapy must be biocompatible and possess high thermal efficiency as heating elements. The biocompatibility of Fe₃O₄ (20-30 nm), ZnFe₂O₄ (15-30 nm) and NiFe₂O₄ (20-30 nm) nanoparticles was studied using a cytotoxicity colony formation assay and a cell viability assay. The Fe₃O₄ sample was found to be biocompatible on HeLa cells. While ZnFe₂O₄ and NiFe₂O₄ were non-toxic at low concentrations, HeLa cells exhibited cytotoxic effects when exposed to concentrations of 100 μg/ml nanoparticles.     

Biocompatible high-moment FeCo-Au magnetic nanoparticles for magnetic hyperthermia treatment optimization

A great deal of attention has been paid to the use of magnetite nanoparticles as heating elements in the research of magnetic fluid hyperthermia. However, these particles have a relatively low magnetization and as a result, have low heating efficiency as well as difficulties in detection applications. To maximize heating efficiency we propose and show the use of high-moment Fe(Co)-Au core-shell nanoparticles. Using a physical vapor nanoparticle-deposition technique the high-moment nanoparticles were synthesized. The water-soluble particles were placed in an AC magnetic field of variable magnetic field frequencies. The temperature rise was measured and compared to theory.     

Cobalt ferrite nanoparticles: The control of the particle size and surface state and their effects on magnetic properties

In order to improve the efficacy of magnetic fluid hyperthermia (MFH) mediators, we synthesised cobalt ferrite nanoparticles with different sizes (between 5 and 7 nm) via successive polyol synthesis. The static and dynamic magnetic properties of the prepared particles, dispersed in a solid matrix, were investigated in order to evaluate the possibility of applying cobalt ferrite as magnetic susceptors in MFH. The effect on magnetic properties coming from the surface anchoring of the model molecule cetyl phosphate, was also investigated.     

High-magnetic-moment multifunctional nanoparticles for nanomedicine applications

Multifunctional FeCo nanoparticles with narrow size distribution (less than 8% standard deviation) were fabricated by a novel physical vapor nanoparticle-deposition technique. The size of magnetic nanoparticles was controlled in the range from 3 to 100 nm. The shape of nanoparticles was controlled to be either spherical or cubic. The particles had a high specific magnetization of 226 emu/g at low saturation field, which is much higher than the currently commercialized iron oxide nanoparticles. Core–shell-type Co(Fe)–Au nanoparticles were produced by the same technique. They combined the high moment of the Co(Fe) core with the plasmonic feature of a Au shell.