Magnetic Nanoparticles Coated with a Thermosensitive Polymer with Hyperthermia Properties

Abstract

Magnetic nanoparticles (MNPs) have been widely used to increase the efficacy of chemotherapeutics, largely through passive accumulation provided by the enhanced permeability and retention effect. Their incorporation into biopolymer coatings enables the preparation of magnetic field-responsive, biocompatible nanoparticles that are well dispersed in aqueous media. Here we describe a synthetic route to prepare functionalized, stable magnetite nanoparticles (MNPs) coated with a temperature-responsive polymer, by means of the hydrothermal method combined with an oil/water (o/w) emulsion process. The effects of both pH and temperature on the electrophoretic mobility and surface charge of these MNPs are investigated. The magnetite/polymer composition of these systems is detected by Fourier Transform Infrared Spectroscopy (FTIR) and quantified by thermogravimetric analysis. The therapeutic possibilities of the designed nanostructures as effective heating agents for magnetic hyperthermia are demonstrated, and specific absorption rates as high as 150 W/g, with 20 mT magnetic field and 205 kHz frequency, are obtained. This magnetic heating response could provide a promising nanoparticle system for combined diagnostics and cancer therapy.

Polyethylene glycol-coated porous magnetic nanoparticles for targeted delivery of chemotherapeutics under magnetic hyperthermia condition

“…In spite of the increased particle size, the hysteresis and coercivity of the synthesized PMNPs were surprisingly negligible, probably due to the particular morphology of the aggregates which are consisted of numerous MNPs with average size of approximately 10 nm and superparamagnetic behavior. Formation of the polymer layer later decreased the specific magnetization value from 49 ± 3 to 34 ± 5 emuÁg À1 , most likely due to the diamagnetic nature of the polymeric nanoshell [36] as well as disordered surface spins [37], whereas no significant alteration was detected in the hysteresis and coercivity values of the nanostructures.…”

Aminodextran Coated CoFe2O4 Nanoparticles for Combined Magnetic Resonance Imaging and Hyperthermia

“…At every 1 s intervals, the temperature was recorded using a Neoptix that is an optical fiber used as a temperature sensor having a resolution of 0.1 • C. The heating curves have been used to obtain the specific absorption rate (SAR) of the CoFe 2 O 4 nanoparticles. This is the amount of heat generated per unit mass of the nanoparticles and calculated by using Equation (3) [27].…”

“…There is a rise of 50 • C in 120 s. Sample 3 attains therapeutic temperatures of 42 to 47 • C from the normal body temperature of 37 • C, at both sets of RF frequencies and magnetic field amplitudes. Saturation was attained in sample 3 after a temperature rise of 50 • C in 250 s. Further quantifiable understanding of the heating efficiencies of the diverse nanoparticles can be attained by calculating SAR values [27]. The initial slope has been extracted from the heating curves to calculate the SAR of the sample in the two different field conditions.…”

Thermosensitive Nanosystems Associated with Hyperthermia for Cancer Treatment

“…The rationale is to combine polymers and superparamagnetic nanoparticles to trigger drug release. Their incorporation into biopolymer coatings enables the preparation of magnetic field-responsive, biocompatible nanoparticles that are well dispersed in aqueous media [78]. Therefore, thermo-responsive nanomaterials of greater interest are those that respond to other stimuli besides temperature.…”