Hyperthermia Applications Research Articles

Investigating Nickel Ferrite (NiFe2O4) Nanoparticles for Magnetic Hyperthermia Applications

Many new promising therapeutic and diagnostic methods in medical science use magnetic nanoparticles (MNPs). Drug targeting, tumor detection, and magnetic hyperthermia treatment are the most common fields of interest where already clinical trials are being performed. Nickel ferrite (NiFe2O4) nanoparticles have received much attention for their potential applications in such fields. A series of samples of Nickel ferrite (NiFe2O4) nanoparticles have been synthesized using a co-precipitation route at different annealing temperatures ranging from 150 ? to 1000 ? and labeling them as S1, S2, S3, S4, and S5. The average particle size obtained from XRD data is found to lie in the range of 15 – 55 nm. The crystal structure of the prepared NiFe2O4 four samples annealed at different temperatures is FCC with a lattice constant of 8.34 Å, which agrees with the values. The magnetic properties of the samples were investigated from temperature-dependent hysteresis loops using Vibrating Sample Magnetometer (VSM). The saturation magnetization (coercivity) is found to increase (decrease) with particle size. The hyperthermia measurements are performed by applying alternating magnetic fields of various amplitudes (Oe) and frequencies (kHz). The measured heating ability of the prepared nanoparticles is obtained from the so-called specific absorption rate (SAR), which is found to increase with increasing frequency and field amplitudes. Using the experimentally obtained SAR value, we also used MATLAB code to model the heat diffusion equation to get information on the temperature rise within the tumor as a function of tumor radius and treatment time.The sample S4 annealed at a temperature of 900 ? is found to be the most suitable candidate for hyperthermia applications at the frequency of 543 kHz because of its capability to produce heat in the therapeutic range of 42-48 ? and with an SAR value of 500 W/g.

Application of magnetic iron oxide nanoparticles: Thrombotic activity, imaging and cytocompatibility of silica-coated and carboxymethyl dextrane-coated particles

Coated iron oxide nanoparticles (IONs) are promising candidates for various applications in nanomedicine, including imaging, magnetic hyperthermia, and drug delivery. The application of IONs in nanomedicine is influenced by factors such as biocompatibility, surface properties, agglomeration, degradation behavior, and thrombogenicity. Therefore, it is essential to investigate the effects of coating material and thickness on the behavior and performance of IONs in the human body. In this study, IONs with a carboxymethyl dextran (CMD) coating and two thicknesses of silica coating (TEOS0.98, and TEOS3.91) were screened and compared to bare iron oxide nanoparticles (BIONs). All three coated particles showed good cytocompatibility (>70%) when tested with smooth muscle cells over three days. To investigate their potential long term behavior inside the human body, the Fe2+ release and hydrodynamic diameters of silica-coated and CMD (carboxymethyl dextrane)-coated IONs were analyzed in simulated body fluids for 72 h at 37 °C. The ION@CMD showed moderate agglomeration of around 100 nm in all four simulated fluids and dissolved faster than the silica-coated particles in artificial exosomal fluid and artificial lysosomal fluid. The particles with silica coating agglomerated in all tested simulated media above 1000 nm. Increased thickness of the silica coating led to decreased degradation of particles. Additionally, CMD coating resulted in nanoparticles with the least prothrombotic activity, and the thick silica coating apparently decreased the prothrombotic properties of nanoparticles compared to BIONs and ION@TEOS0.98. For magnetic resonance applications, ION@CMD and ION@TEOS3.91 showed comparatively high relaxation rates R2 values. In magnetic particle imaging experiments ION@TEOS3.91 yielded the highest normalized signal to noise ratio values and in magnetic hyperthermia studies, ION@CMD and ION@TEOS0.98 showed similar specific loss power. These findings demonstrate the potential of coated IONs in nanomedicine and emphasize the importance of understanding the effect of coating material and thickness on their behavior and performance in the human body.

Dipolar and anisotropy effect on dextran coated Cu doped ferrite for magnetic hyperthermia applications

The dipolar interaction and magnetic anisotropy effect are the key parameters to tune the self-heating effect of magnetic nanoparticles (MNPs). In this paper, we investigate the impact of Cu2+ doped Fe3O4 and dextran coated nanoparticles (CuxFe3-xO4 with x = 0.15, 0.31, and 0.47) on thermal properties using specific absorption rate measurements (SAR). We look into the prospect of using dipolar and anisotropy effects to increase or decrease the heat released by magnetic nanoparticles, potentially boosting hyperthermia applications. Magnetic nanoparticles with an average particle size of 12–20 nm were observed via TEM. The influence of Cu2+ doping on the structural and magnetic properties of the samples was studied using a vibrating sample magnetometer (VSM). The effective anisotropy calculated for x = 0.15 and x = 0.47 were 5.5 and 4.4 j/m3 respectively. It was shown that increasing the copper doping reduced the effective anisotropy, lowering the SAR values. The SAR value obtained for x = 0.15 and dex-x = 0.15 were 787 and 591 W/g respectively. The uncoated CuxFe3-xO4 nanoparticles achieved hyperthermia temperatures (42–48 °C) much faster than the dextran-coated samples. Eventually temperature can be adjusted to the desired hyperthermia temperature range by altering the sample and Cu2+ concentration. The dextran coating has been shown to dramatically reduce SAR values while still assisting in magnetic hyperthermia temperature regulation. The study also demonstrated that the dipolar interaction influenced the Néel relaxation mechanism which was important in the heat generation mechanism of the MNPs

New synthesis route for high quality iron oxide-based nanorings: Structural and magnetothermal evaluations

The present study reports on the successful fabrication of high quality monocrystallite magnetite (Fe3O4) nanorings, based on the transformation of monocrystallite hematite (α-Fe3O4) nanorings, using a wet and mild-temperature-mediated chemical route, as an alternative to the traditional solid–solid annealing methods. Additionally, attempts to fabricate ferrite-based nanorings with different stoichiometry through metal-ion (Mn2+, Zn2+, Co2+, and Fe2+) doping and using solid–solid reaction by annealing the hematite nanorings is herein reported. The nanoring morphology is confirmed by electron microscopy micrographs whereas typical magnetic vortex signature is revealed in magnetic hysteresis cycle measurements recorded at room temperature, via collapsing of open loop at low magnetic fields. Rietveld refinement analysis revealed fabrication of single-phase (except one sample revealing two phases) and high-quality crystalline nanomaterials, identified with standard ICDD cards. The as-fabricated samples were tested in regard to their performance for magnetic hyperthermia application, using AC magnetic field amplitude of 100, 150, 200, and 240 Oe while setting frequency at 330 kHz. The recorded temperature versus time curves were successfully explained by the Box-Lucas method.

МОДЕЛЮВАННЯ ПРОЦЕСУ ІНДУКЦІЙНОГО НАГРІВУ ДЛЯ СИСТЕМ МАГНІТНОЇ ГІПЕРТЕРМІЇ

The paper is devoted to the challenges of applying the induction heating (IH) for magnetic hyperthermia. The analysis of the results of previous studies has shown that within the biologically safe range of AC magnetic fields, insufficient induction heating power still appears to be one of the key problems for the successful clinical application of magnetic hyperthermia. In this paper, several possible effective circuit design solutions for the IH system are proposed, and their influence on the parameters of the heating processes of ferrites and ferromagnets is investigated. The model of the induction heater created in COMSOL Multiphysics allowes to simulate the distribution of current density and temperature in the heater. The developed model ensures better assessment of the processes occurring in living tissues and enables to simulate the impact of the magnetic particle material type and size on the temperature of heating and power consumption of the device.

Development of core-shell nanocomposites containing iron oxide,silica and samarium for potential application in cancer treatments involving brachytherapy and magnetic hyperthermia

Nanocomposites formed of natural-origin iron oxide nanoparticles (magnetite and maghemite, Fe3O4 and γ-Fe2O3, respectively) were processed using the sol-gel process into core-shell structures containing silica and samarium to investigate their potential for applications in cancer treatments combining hyperthermia and brachytherapy. Mössbauer characterization showed that the iron oxides contained 64% magnetite, 18% hematite, 12% maghemite, and exhibit superparamagnetic behavior at room temperature. Transmission electron microscopy determined that the iron oxide particles were smaller than 15 nm, while magnetization was measured at 5 emu/g. Fourier transform infrared indicated the material was formed of Si-O-Si and Fe-O-Si bonds, while X-ray diffraction showed bands of amorphous silica from 5° to 23° and bands of iron oxide phases. X-ray fluorescence indicated 5.17% of incorporated samarium. The nanocomposite suspensions were subjected to an alternating magnetic field and the resulting heat dissipation was measured, falling within the ideal range for hyperthermia applications. Theoretical dosimetric calculation determined significant radioactive activity of 1.68x10-8 MBq.mg-1.Φ -1 after 24h decay time for 153Sm. The characteristics and behavior of these nanocomposites indicate that they may offer promise in applications involving hyperthermia for cancer treatment and a more accessible source for brachytherapy materials.

Electron spin resonance and induction heating studies of zinc substituted (Mn, Co) ferrite nanoparticles for potential magnetic hyperthermia applications

This study presents an investigation on the various spin relaxation processes taking place at X-Band microwave energy in Zn substituted MnFe2O4 and CoFe2O4 and their induction heating studies. The material properties of these citric acid assisted sol-gel synthesized nanoparticles have been explored using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), Field emission scanning electron microscope, Vibrating sample magnetometer (VSM) and Electron spin resonance spectroscopy. XRD and Rietveld refinement confirm the face centered cubic spinel structure of the synthesized samples, which is further supported by the observation of absorption bands characteristic of the spinel ferrites in the FTIR spectra. The remanence, coercivity and effective magnetocrystalline anisotropy values from VSM studies show lower value with zinc substitution which is desirable for biomedical application. Various spin resonance parameters like gyromagnetic ratio, peak to peak linewidth, resonance field, spin-lattice and spin-spin relaxation times have been calculated. The induction heating studies of the samples in an alternating magnetic field have been carried out using a field strength of 4.58 × 109 Am-1s-1. All the investigated MNPs are able to raise the temperature to the therapeutic limit of 42–45 °C. The specific absorption rate (SAR) which describe the heating potential of the MNPs is calculated using four different concentrations of each sample - 5 mg mL-1, 10 mg mL-1, 15 mg mL-1 and 20 mg mL-1. SAR values are found to decrease with increase in concentration and achieve the highest value of 303 W/g for Co0.5Zn0.5Fe2O4 nanoparticles with 5 mg mL-1 concentration. The ability of the MNPs to give rise to the therapeutic temperature points toward their suitability as an effective heat mediator in magnetic hyperthermia treatment of cancer.

Breast tumor‐targeted drug delivery via polymer nanocarriers: Endogenous and exogenous strategies

AbstractBreast cancer, one of the most common types of cancer worldwide, has a high degree of malignancy while lacking efficient treatments. The off‐target events frequently occurring in drug administration have been a major obstacle, which causes severe side effects to patients and reduces the therapeutic efficacy. An ideal medication should precisely target the specific site with precise control over concentration and duration. In recent years, there has been immense progress in polymer nanocarriers that demonstrate great potential in the targeted delivery. These nanocarriers are constructed from materials sensitive to a wide range of endogenous (e.g., pH, enzyme, redox) and exogenous stimuli (e.g., light, ultrasound, magnetic waves), driving cargo release to the targeted tissue or cells. Here, we elucidate the mechanism of current targeting strategies and the engineering methods to construct these targeting systems or to improve their targeting efficiency. We capture the recent progress in the targeted nanocarriers derived from polymers which span hydrogels and micelles, demonstrating their design and applications in chemo, hyperthermia, immuno, and gene therapies.

Evaluating the applications and effectiveness of magnetic nanoparticle-based hyperthermia for cancer treatment: A systematic review

Magnetic nanoparticle-based hyperthermia as a new cancer treatment technology has been applied for some kinds of tumors. To review the different applications and effectiveness of this new cancer treatment technique, PubMed, Science Direct, Web of Science, and Google Scholar databases were explored up to November 2022, using the following keywords combined in different ways: “Magnetic Nanoparticles Based Hyperthermia”, “Magnetic Nanoparticles” AND “Hyperthermia” AND “Cancer”. The obtained results were screened for the title and abstract and the relevant papers were reviewed for further details. Finally, 24 papers were included in the study. These papers have evaluated the application of magnetic nanoparticle-based hyperthermia for treating different cancers including breast, liver, prostate, pancreas, colon, brain, lung, and stem cell. Various nanoparticles including Iron Oxide (Fe2O3, Fe3O4), Dextran Spermine, Iron Chloride, Magnetic nanoparticles conjugated with Liposomes (MCLs), and Variable Molecular Weight Nanoparticles (VMWNPs) were used in different reviewed studies. The results of reviewed studies revealed that the nanoparticle-based hyperthermia technique as a new progressive modality can significantly improve treatment outcomes for some special cancers. Increasing life expectancy by up to 30% using Iron Oxide magnetic nanoparticle-based hyperthermia for pancreatic cancer and increasing tumor ablation by about 33% for other cancers were reported in reviewed articles. However, further studies are required to extend this new treatment technique to other cancers and for providing more accurate information on nanoparticle-based hyperthermia's effectiveness as a complementary technique in cancer treatment.

Study of protein encapsulated manganite nanoparticles for magnetic Hyperthermia

Used in the past as an efficient drug-delivery carrier, the natural protein Bovine Serum Albumin (BSA) has been tried in the present study to coat Lanthanum Strontium Manganese Oxide (LSMO) nanoparticles (NPs) called manganite, for magnetic Hyperthermia applications. LSMO NPs generate heat when subjected to a radiofrequency magnetic field and as a novel attempt; they were functionalized with BSA by its “denaturation” at 80°C. This was done to probe the effect of protein bonding with nanoparticles by “unfold” of its molecular structure and to enhance the biocompatibility of LSMO. Presence of BSA on NPs was assessed through electron microscopy (HRTEM), Fourier transform (IR) spectroscopy and thermogravimetric analysis (TGA); that showed successful outcomes. The magnetization was analyzed by super quantum interface device (SQUID). For Hyperthermia studies, BSA coated NPs were dispersed in phosphate buffer saline and attained an appreciable specific absorption rate of 126.9 W/g showing their potential for future applications.

Synthesis of CoFe2O4-CaCO3 nanocomposite for simultaneous magnetic hyperthermia and drug release applications

In the present research, CoFe2O4 nanostructures were produced using a sol-gel auto-combustion method. A novel approach was used for the synthesis of CoFe2O4-CaCO3 nanocomposite. The synthesized CoFe2O4-CaCO3 nanocomposite was examined for hyperthermia and drug release applications. Different methods including vibrating-sample magnetometer (VSM), X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier Transform infrared spectroscopy (FTIR), and field emission scanning electron microscopy (FESEM) were used to characterize the produced powders. TEM images showed that spherical and irregular particles were formed in the samples with particle sizes ranging from 30 to 60 nm. The cytotoxicity of the nanocomposite was evaluated via MTT assay using MG63 cells, which revealed that by increasing the percentage of CaCO3, the viability of the cells was increased. The sustained drug release revealed that the samples had an appropriate drug loading and controlled drug delivery capability in 72 h. Furthermore, with various magnetic fields or cobalt ferrite to CaCO3 ratios, it is feasible to produce heat and prepare this nanocomposite for magnetic hyperthermia-based treatment. SAR parameter calculation demonstrated that the samples were a suitable candidate for hyperthermia treatment. The current research demonstrates that a new method could be applied for making pH-sensitive CoFe2O4-CaCO3 as a magnetic nanocarrier for cancer treatment.

Influence of the modifiers in polyol method on magnetically induced hyperthermia and biocompatibility of ultrafine magnetite nanoparticles

Magnetite nanoparticles (Fe3O4 NPs) are widely tested in various biomedical applications, including magnetically induced hyperthermia. In this study, the influence of the modifiers, i.e., urotropine, polyethylene glycol, and NH4HCO3, on the size, morphology, magnetically induced hyperthermia effect, and biocompatibility were tested for Fe3O4 NPs synthesized by polyol method. The nanoparticles were characterized by a spherical shape and similar size of around 10 nm. At the same time, their surface is functionalized by triethylene glycol or polyethylene glycol, depending on the modifiers. The Fe3O4 NPs synthesized in the presence of urotropine had the highest colloidal stability related to the high positive value of zeta potential (26.03 ± 0.55 mV) but were characterized by the lowest specific absorption rate (SAR) and intrinsic loss power (ILP). The highest potential in the hyperthermia applications have NPs synthesized using NH4HCO3, for which SAR and ILP were equal to 69.6 ± 5.2 W/g and 0.613 ± 0.051 nHm2/kg, respectively. Their application possibility was confirmed for a wide range of magnetic fields and by cytotoxicity tests. The absence of differences in toxicity to dermal fibroblasts between all studied NPs was confirmed. Additionally, no significant changes in the ultrastructure of fibroblast cells were observed apart from the gradual increase in the number of autophagous structures.

Electromagnetic Performance of NiMgCuZn Ferrite for Hyperthermia Application in Cancer Treatment.

Ferrite with high permeability, high magnetic loss, and a low Curie temperature is a highly promising material for hyperthermia applications in cancer treatment. In this work, Ni(0.29-x)MgxCu0.14Zn0.60Fe1.94O3.94 (NiMgCuZn) ferrites were prepared at different Mg ion concentrations. The dependence of the Mg ion contents on the crystal structure, magnetic, and permeability properties of NiMgCuZn ferrite was investigated. Structural characterization showed a high crystallinity of the materials and an increase in the lattice constant with the Mg ion content. The magnetic hysteresis loops revealed that the saturation magnetization decreased with an increasing Mg content. Furthermore, the permeability measurements showed an increase in permeability and magnetic loss with the doping of Mg. More importantly, the Curie temperature of the NiMgCuZn ferrite decreases with the Mg ion content and reaches 42.37 °C for x = 0.26 as well as a real permeability of ∼797.88@1 MHz and a magnetic loss of 0.316@1 MHz, which meet the requirements of tumor hyperthermia.

Graphene Oxide/Reduced Graphene Oxide Nanomaterials for Targeted Photothermal Cancer Therapy

Abstract: A combination of cancer therapy (hyperthermia with other therapies) holds tremendous potential for therapeutic improvement. Conventional methods of inducing hyperthermia are incapable of limiting a high-temperature increase at the tumor location while also preserving unexposed healthy tissues. Different materials available are not suitable for the combined application of hyperthermia and photothermal therapy (PTT). The use of carbonbased nanomaterials for cancer therapy has increased rapidly due to their ability to transport various anticancer drugs and to function as a photothermal agent. In this regard, the graphene family of 2D carbon nanomaterial graphene oxide (GO) and reduced graphene oxide (rGO) has emerged as a promising candidate for cancer PTT due to its excellent photothermal conversion in the near-infrared range, large specific surface area for drug loading, and scope for functionalization with functional groups/ molecules such as photosensitizers, siRNA, ligands, and so on with no cumulative toxicity. The availability of functional groups such as hydroxyls, epoxides, and carbonyls on GO groups, renders flexible modification leading to biocompatibility, facilitating it for an ideal drug delivery vector. In the present review, recent advances in combinational PTT providing synergistic benefits of multiple modalities are discussed.

A Comparative Study on the Effect of Different Sintering Temperatures on Structural and Magnetic Properties of Mg–Zn Ferrite Nanoparticles

The current study involved the synthesis of magnesium zinc ferrite (Mg0.8Zn0.2Fe1.4Al0.6O4) using the sol–gel method. Various techniques such as X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier Transform Infrared (FTIR), vibrating sample magnetometer (VSM), and radiofrequency (RF) induction were utilized to analyze the properties of the synthesized ferrite nanoparticles. The objective was to examine how different sintering temperatures affected the structural and magnetic characteristics of Mg0.8Zn0.2Fe1.4Al0.6O4. The XRD analysis confirmed the presence of a well-defined single phase crystalline structure with a spinel arrangement. Increasing the annealing temperature resulted in larger nanoparticles, ranging from 28.38 nm to 30.14 nm. SEM provided information about the morphology, agglomeration, and grain size of the ferrite, revealing a grain size ranging from 326 nm to 485 nm. The FTIR spectroscopy indicated a single-phase spinel structure for the prepared sample. The magnetic properties of the sample were evaluated using VSM, showing a maximum magnetization of 45.6 emu/gm and the least coercivity of 90 Oe at an annealing temperature of 900 °C. RF induction at a frequency of 108 kHz exhibited superior results for the sample annealed at 900 °C compared to those annealed at 700 °C and 800 °C. At this frequency, the specific absorption rate (SAR) value was high, making it suitable for magnetic hyperthermia applications. The prepared magnesium zinc ferrite demonstrated suitability for both low and high frequency devices, and it could be employed in various technological applications, including microwave devices, inductor cores, transformers, and other electronic devices.

Extirpating the cancer stem cell hydra: Differentiation therapy and Hyperthermia therapy for targeting the cancer stem cell hierarchy.

Ever since the discovery of cancer stem cells (CSCs), they have progressively attracted more attention as a therapeutic target. Like the mythical hydra, this subpopulation of cells seems to contribute to cancer immortality, spawning more cells each time that some components of the cancer cell hierarchy are destroyed. Traditional modalities focusing on cancer treatment have emphasized apoptosis as a route to eliminate the tumor burden. A major problem is that cancer cells are often in varying degrees of dedifferentiation contributing to what is known as the CSCs hierarchy and cells which are known to be resistant to conventional therapy. Differentiation therapy is an experimental therapeutic modality aimed at the conversion of malignant phenotype to a more benign one. Hyperthermia therapy (HT) is a modality exploiting the changes induced in cells by the application of heat produced to aid in cancer therapy. While differentiation therapy has been successfully employed in the treatment of acute myeloid leukemia, it has not been hugely successful for other cancer types. Mounting evidence suggests that hyperthermia therapy may greatly augment the effects of differentiation therapy while simultaneously overcoming many of the hard-to-treat facets of recurrent tumors. This review summarizes the progress made so far in integrating hyperthermia therapy with existing modules of differentiation therapy. The focus is on studies related to the successful application of both hyperthermia and differentiation therapy when used alone or in conjunction for hard-to-treat cancer cell niche with emphasis on combined approaches to target the CSCs hierarchy.

Tuning between composition and nanoparticle size of manganites for self-regulated magnetic hyperthermia applications

Self-regulated magnetic hyperthermia is a promising alternative for cancer treatment based on tumor annihilation by heating using appropriate Curie temperature () as an internal temperature controller. We successfully prepared strontium-doped lanthanum manganite nanoparticles (LSMO-x) using the sol-gel method. The can be adjusted by modifying both the composition and diameter of the particles, that is, varying the Sr content (0.2 0.3) and the annealing temperature (600 ∘C, 700 ∘C, and 800 ∘C). Structural, morphological, chemical, and magnetic properties were investigated. The samples exhibit the structure of perovskites with average particle sizes ranging from 17 nm to 27 nm, depending on the annealing temperature. This diameter range ensures that all samples investigated are have negligible remanence at room temperature. Magnetization studies show that increases as Sr content and particle size increase, indicating that the is governed by both. Thus can be adjusted by combining these two parameters for self-regulated magnetic hyperthermia. Magnetic hyperthermia measurements showed that samples with larger particle sizes (19 nm) were more efficient in promoting heat, that is, presenting a higher specific absorption rate (SAR), probably due to the adequate balance between the Néel and Brownian relaxations behavior. We figure out that the SAR value is essential for this specific finality, but it should also consider the maximum temperature reached during the hyperthermia essays. Finally, we build up a nanoparticle diameter vs. Sr concentration phase diagram, where the SAR values are displayed, which allows for predicting the best sample for the self-regulated hyperthermia.

An elliptical‐shaped rectangular slot antenna at 2.48 GHz for hyperthermia application

AbstractIn this paper, a novel integrated elliptical ringtone antenna has been proposed. The proposed antenna operates in the industrial, scientific and medical band and the overall size of the antenna is 128 × 128 × 1.58 mm3. The antenna provides a valid specific absorption rate input profile and displays better performance at 2.48 GHz. Simulation of the proposed structure was done on FEM‐based high frequency structure simulator 2020R1 software and validated by measured results.

Specific absorption rate of randomly oriented magnetic nanoparticles in a static magnetic field.

Numerical simulations using the stochastic Landau-Lifshitz equation are performed to study magnetization dynamics of dilute assemblies of iron oxide nanoparticles exposed to an alternating (ac) magnetic field with an amplitude H ac = 200 Oe and a frequency f = 300 kHz and a static (dc) magnetic field in the range H dc = 0-800 Oe. The specific absorption rate (SAR) of the assemblies is calculated depending on the angle between the directions of the ac and dc magnetic fields. For the case of an inhomogeneous dc magnetic field created by two opposite magnetic fluxes, the spatial distribution of the SAR in the vicinity of the field-free point is obtained for assemblies with different nanoparticle size distributions. The results obtained seem to be helpful for the development of a promising joint application of magnetic nanoparticle imaging and magnetic hyperthermia.

Magnetic Gels in Skin Cancer Treatment: A Review of Potential Applications in Diagnostics, Drug Delivery and Hyperthermia.

Skin cancer (SC) is affecting an increasing number of people worldwide. Its lesions affect mainly the most exposed regions of the skin. SC is classified into to main categories: non-melanoma (basal cell carcinoma of the epidermis and squamous cell carcinoma) and melanoma (the abnormal proliferation of melanocytes, which is rarer, more hazardous, and more deadly). Prevention and early diagnosis are important actions, and surgery is often considered. After the removal of cancerous lesions, the local administration of medicine can guarantee anticancer therapeutic action, rapid healing and the recovery of tissue, ensuring the absence of recurrence. Magnetic gels (MGs) have attracted increased attention regarding their pharmaceutical and biomedical applications. They are magnetic nanoparticles (e.g., iron oxide nanoparticles) dispersed in a polymeric matrix, which constitute adaptive systems under a magnetic field. MGs can combine magnetic susceptibility, high elasticity, and softness, and are thus useful platforms for diagnostics, drug delivery, and also for hyperthermia. This manuscript reviews MGs as a technological strategy for the treatment of SC. An overview of SC and the treatment, types, and methods of preparing MGs are discussed. Moreover, the applications of MGs in SC and their future perspectives are considered. The combination of polymeric gels and magnetic nanoparticles continues to be investigated, and new products must hit the market. Clinical trials and new products are expected, due to the important advantages of MGs.