Hyperthermia Applications Research Articles

Magnetic xanthan gum-silk fibroin hydrogel: A nanocomposite for biological and hyperthermia applications

A magnetic xanthan hydrogel/silk fibroin nanobiocomposite (XG hydrogel/SF/Fe3O4) was designed, fabricated, and characterized using analyzing methods such as FT-IR, EDX, FE-SEM, XRD, TGA, and VSM to evaluate the exact structure of product nanobiocomposite. The FE-SEM images reveal the presence of spherical shapes exhibiting a narrow size range and homogeneous distribution, measuring between 30 and 35 nm in diameter. The VSM analysis demonstrates the superparamagnetic properties of the XG hydrogel/SF/Fe3O4 nanobiocomposite, exhibiting a magnetic saturation of 54 emu/g at room temperature. The biological response of the nanobiocomposite scaffolds was assessed through cell viability and red blood cell hemolytic assays. MCF10A cells were exposed to a concentration of 1.75 mg/mL of the nanobiocomposite, and after 2 and 3 days, the cell viability was found to be 96.95 % and 97.02 %, respectively. The hemolytic effect was nearly 0 % even at higher concentrations (2 mg/mL). Furthermore, the magnetic nanobiocomposite showed excellent potential for hyperthermia applications, with a maximum specific absorption rate of 7 W/g for 1 mg/mL of the sample under a magnetic field in different frequencies (100, 200, 300, and 400 MHz) and 5 to 20 min time intervals.

Effect of Gd substitution on structure, optical and magnetic properties, and heating efficiency of Fe3O4 nanoparticles for magnetic hyperthermia applications

This work presents the synthesis of Fe3-xGdxO4 nanoparticles and the investigation of the impact of Gd content (x) on structural characteristics of nanoparticles, including lattice parameters, crystallite size, and X-ray density. The high-resolution images of Transmission Electron Microscopy reveal that the synthesized Fe3-xGdxO4 nanoparticles have a narrow distribution in size statistics between 9 and 12.5 nm. Interestingly, analyzing different prepared samples reveals that both the saturation magnetization and magnetic anisotropy decrease simultaneously with the increase of band gap while remaining independent of the specific absorption rate (SAR) value. The SAR is greater than that of pure Fe3O4 nanoparticles. In a specific case of Fe2.75Gd0.25O4 sample where the optimal value of x is 0.25, the highest SAR value obtained is 237.4 W/g. Besides, the experimental results demonstrate an optimal doping content with the highest SAR value of Fe2.75Gd0.25O4 nanoparticles along with the theoretical explanation by analyzing the Linear Theory Response framework based on the relationship between magnetic anisotropy and diameter with SAR value. The theoretical and experimental evidence fully demonstrate that doping is an effective approach for optimizing as-synthesized NPs to enable efficient hyperthermia applications.

Influence of polyethylene glycol and Gongronema latifolium on the structural, optical and magnetic properties of magnesium ferrite nanoparticles for hyperthermia applications

ABSTRACT Ferrite materials have found applications in various fields, particularly in biomedical fields. This work involves the preparation of Magnesium ferrite nanoparticles (MgFNPs) by biosynthesis protocol using polyethylene glycol (PEG-4000) and gongronema latifolium (GL) extracts as capping and reducing agents, to heighten the properties of MgFNPs for effective hyperthermia applications. Various characterization techniques were used to determine the properties of the formulated samples. Spherical morphology with low agglomeration was observed by the SEM analysis. The XRD showed a crystallite size between 10 and 49 nm. The VSM confirmed the superparamagnetic nature of the samples. The heating ability was observed to decrease to the therapeutic rage with GL and PEG. However, further investigations for the hyperthermia application were performed on the formulated samples by estimating their Specific loss power (SLP). The samples showed high SLP between 130.6 and 290.8 W/g. The materials capped with PEG has better properties for hyperthermia applications.

Oxygen vacancy enhanced magnetic heating efficiency of ferrite nanoparticles for self-regulating temperature hyperthermia

Precise and controllable temperature is required for using magnetic hyperthermia in cancer therapy. Magnetic nanoparticles typically need to have a Curie temperature of 42–50 °C to self-regulate hyperthermia temperature via magnetic phase transition. For now, the most studied iron oxide nanoparticles are not suitable for self-regulating hyperthermia applications due to their high Curie temperature of several hundred Celsius degrees. Doping nonmagnetic metal ions into iron oxide nanoparticles is an effective way to decrease Curie temperature, but often leads to low saturation magnetization and poor magnetic heating efficiency, limiting its usage in hyperthermia applications. Magnetic nanoparticles with excellent magnetic heating efficiency and suitable Curie temperature are highly desirable. This paper proposes an approach for enhancing magnetic heating efficiency by regulating oxygen vacancy concentration. Mn0.46Zn0.54Al0.25Fe1.75O4 nanoparticles with Curie temperature at 44.5 °C are prepared by co-precipitation method. Effective regulation of oxygen vacancy concentrations is achieved through hydrogen peroxide oxidation and carbothermal reduction treatments. Research results suggest that increasing oxygen vacancies significantly enhance the magnetism due to the transformation of magnetic couplings on nanoparticles, while barely affecting the Curie temperature. These nanoparticles exhibit high magnetic heating efficiency under an alternating magnetic field, almost 1.5 times of clinical-grade iron oxide nanoparticles, and can self-regulate hyperthermia temperature at 48–49 °C. This work may provide some references for further research on self-regulating temperature magnetic hyperthermia.

Synergistic effect of CoFe2O4–85S nano bio-glass composites for hyperthermia and controlled drug delivery

Cancer, a devastating disease is a significant cause of mortality in recent times, continues to pose formidable challenge in terms of finding effective treatments. In this context, we present a pioneering approach that combines bone tissue regeneration, hyperthermia and controlled drug delivery using nanocomposites composed of 85S (85SiO2–10CaO-5P2O5 (mol%)) bio-glass and cobalt ferrite (CoFe2O4) nanoparticles, synthesized using Stober's method and a modified microwave reflux method, respectively. The formation of hydroxyapatite (HAp) layer after immersion in simulated body fluid (SBF) is confirmed through XRD, FTIR, and SEM measurements. Among all nanocomposites, 7.5 wt% of cobalt ferrite with 85S bio-glass (CFO_7.5) demonstrates the maximum formation of a HAp, indicating its potential for bone tissue regeneration. MTT assay confirms the remarkable biocompatibility against MG-63 osteoblastic cells, displaying higher cell viability of about 220% after 72 h for CFO_7.5. Significantly, it also demonstrates remarkable antimicrobial activity against both E. coli and S. aureus cells. Although M vs H measurements show superparamagnetic behaviour at room temperature for all the nanocomposites, CFO_7.5 exhibits a gradual and consistent heating rate, making it an ideal thermo-seed material for hyperthermia applications. Besides, 80% of drug loading and 97% of cumulative release at 7.4 pH has been observed in CFO_7.5 due to its mesoporous structure and high surface area confirmed from BET analysis. In-vitro experiments provide compelling evidence of the remarkable bioactivity, potent antimicrobial and sustained drug release capabilities along with the ability to generate controlled heat that makes CFO_7.5 a potential candidate for hyperthermia and control drug delivery in treating cancer.

A threefold increase in SAR performance for magnetic hyperthermia by compositional tuning in zinc-substituted iron oxide superparamagnetic nanoparticles with superior biocompatibility

In this work, we report a ultrahigh specific absorption rate (SAR) performance in Zn-substituted magnetite superparamagnetic (SPM) nanoparticles (NPs) for potential application in magnetic hyperthermia (MHT)-based cancer treatment. Although MHT shows promise in cancer therapy, challenges such as low heating performance, agglomeration of magnetic nanoparticles (MNPs) in blood veins, cytotoxicity, and hemocompatibility have hindered clinical uses. To overcome these challenges, we adopted a reverse-micelles based coprecipitation synthesis approach to prevent MNPs agglomeration and optimized the substitution of Zn ions in magnetite to enhance heating performance. Calorimetric measurements showed SAR values of 118 W/g and 181 W/g for magnetite NPs using the initial slope method (ISM) and Box Lucas method (BLM), respectively. Through our compositional optimizations, we achieved a significant increase in SAR value by consciously substituting Zn2+ ions in the magnetite lattice. Specifically, we obtained SAR values of 325 W/g and 579 W/g (>300% increase) for Zn0.3Fe2.7O4 MNPs using ISM and BLM, respectively. This enhancement can be attributed to improved saturation magnetization (174–257 kA/m) and magneto-crystalline anisotropy (12–24 kJ/m3). The increase in saturation magnetization in the magnetite MNPs can be explained by the higher magnetic moment resulting from increased Zn concentration up to ZnxFe3-xO4(x = 0.3), strengthening the JAB interaction. However, further increases in Zn concentration lead to a decrease in saturation magnetization due to non-collinearity, as described by the Yafet-Kittle model. Our optimized MNPs exhibit improved heating performance, enabling the use of lower MNPs concentrations for cancer treatment, reducing potential toxicity effects. Biocompatibility investigations demonstrated a low hemolysis rate (<5%) in a hemolysis assay with red blood cells and high cytocompatibility (>92% cell viability) in MTT assays for all compositions, confirming their potential suitability for clinical applications. This study offers a promising approach to enhance SAR performance, addressing MHT-based cancer treatment challenges, and improving clinical suitability.

Magnetic Nanoparticles as Mediators for Magnetic Hyperthermia Therapy Applications: A Status Review

This concise review delves into the realm of superparamagnetic nanoparticles, specifically focusing on Fe2O3, Mg1+xFe2−2xTixO4, Ni1−xCux, and CrxNi1−x, along with their synthesis methods and applications in magnetic hyperthermia. Remarkable advancements have been made in controlling the size and shape of these nanoparticles, achieved through various synthesis techniques such as coprecipitation, mechanical milling, microemulsion, and sol–gel synthesis. Through this review, our objective is to present the outcomes of diverse synthesis methods, the surface treatment of superparamagnetic nanoparticles, their magnetic properties, and Curie temperature, and elucidate their impact on heating efficiency when subjected to high-frequency magnetic fields.

An exhaustive scrutiny to amplify the heating prospects by devising a core@shell nanostructure for constructive magnetic hyperthermia applications

An interfacial integration at the nanoscale domain through a core@shell (CS) nanostructure has constructively unbarred a wide dimension to researchers on biomedical applications, especially for magnetic fluid hyperthermia. Lately, the interconnection of the exchange bias effect (EBE) through the interface coupling to the magnetic heating efficiency has uttered its utmost prominence for researchers. Here, we delineate the ascendency of the heating ability through a coalescing assembly of mixed ferrite Co0.5Zn0.5 Fe2O4 (CZ) and soft magnetic material Fe3O4 (F), by devising a network of CoZnFe2O4@Fe3O4 (CZF) CS nanostructure. A hefty interface activity with validation of the EBE phenomenon is divulged through magnetic scrutiny for the CS sample. The magnetic nanoparticles heating response to applied magnetic field and frequency is discerned at three distinct fields, where the outcome prevailed to inflated specific loss power for CS CZF in distinction to bare F and CZ samples for all the assessments. Remarkably; a lofty intrinsic loss parameter is also perceived for the CS sample recorded to about 5.36 nHm2 g−1; which is another eccentric outcome that significantly labels the CS CZF sample as a potentially high heating competence agent. This comprehension accords to a finer perspective to meliorate the theranostic environment for hyperthermia applications.

Quantifying the Efficacy of Magnetic Nanoparticles for MRI and Hyperthermia Applications via Machine Learning Methods.

Magnetic nanoparticles are a prospective class of materials for use in biomedicine as agents for magnetic resonance imagining (MRI) and hyperthermia treatment. However, synthesis of nanoparticles with high efficacy is resource-intensive experimental work. In turn, the use of machine learning (ML) methods is becoming useful in materials design and serves as a great approach to designing nanomagnets for biomedicine. In this work, for the first time, an ML-based approach is developed for the prediction of main parameters of material efficacy, i.e., specific absorption rate (SAR) for hyperthermia and r1 /r2 relaxivities in MRI, with parameters of nanoparticles as well as experimental conditions as descriptors. For that, a unique database with more than 980 magnetic nanoparticles collected from scientific articles is assembled. Using this data, several tree-based ensemble models are trained to predict SAR, r1 and r2 relaxivity. After hyperparameter optimization, models reach performances of R2 = 0.86, R2 = 0.78, and R2 = 0.75, respectively. Testing the models on samples unseen during the training shows no performance drops. Finally, DiMag, an open access resource created to guide synthesis of novel nanosized magnets for MRI and hyperthermia treatment with machine learning and boost development of new biomedical agents, is developed.

Investigation of Cr3+ doped Zn-Co nanoferrites as potential candidate for self-regulated magnetic hyperthermia applications

Controlling the Curie temperature (TC) in the range from 42 °C–46 °C in magnetic hyperthermia (MH) therapy is an essential research topic because overheating can cause irreversible damage to healthy tissue. When TC is in the above temperature range, the magnetic nanoparticles reach a paramagnetic state, effectively turning off the MH treatment. In this work, we synthesized Zn-Co nanoparticles of representative composition Zn0.54Co0.46CrxFe2-xO4, where the Fe3+ cations are carefully replaced by Cr3+ ions, which allow a precise tuning of TC and hence the self-regulation of MH. The x-ray diffraction analysis of the prepared nanoparticles confirms the formation of a single-phase cubic spinel structure. The average crystallite of the nanoparticles increases with Cr3+ doping, while the Tc and saturation magnetization decrease considerably from 78 °C (x = 0.1) to 27 °C (x = 0.6) and 46.6 emu g−1 (x = 0.1) to 15.3 emu g−1 (x = 0.6), respectively. Besides MH potential of the investigated samples as revealed from specific absorption rate (SAR) assays and the maximum temperature reach (Tmax), vary from 7 W g−1 and 37.3 °C, for x = 0.6, to 38 W g−1 and 62.9 °C, for x = 0.1, we found that the composition Zn0.54Co0.46Cr0.4Fe1.6O4 is more promising with SAR of 22 W g−1 and Tmax = 42.3 °C, which is precisely lies in the safe temperature range to automatically activate the self-regulation during the magnetic hyperthermia treatment. The results reveal an excellent combination between size distribution and Cr3+ content in Zn-Co-based ferrite, which has a great potential for self-regulated magnetic hyperthermia applications.

Influence of long-term thermal treatment of magnetite nanoparticles on its physicochemical properties

In the presented paper, a long term thermal treatment at 50 °C was performed on four types of magnetite nanoparticles to observe if there is a transformation induced to other iron oxides. Such information is critical when hyperthermia application is foreseen due to different magnetic properties of Fe3O4, γ-Fe2O3 and α-Fe2O3. Nanoparticles were obtained by co-precipitation of iron (II) and (III) chlorides or by thermal decomposition of iron (III) acetylacetonate. Both types of nanoparticles were covered with a protective silver shell to increase their oxidative stability. The experiment was conducted in phases over the course of 28 days. Characterization of thermally treated nanoparticles was performed by transmission electron microscopy, x-ray diffraction, infrared spectroscopy and Mössbauer spectroscopy. According to the obtained results, nanoparticles synthesized by co-precipitation of iron chlorides are less thermally stable than those obtained by thermal decomposition. However, both types of nanoparticles do not oxidize to hematite even when exposed to long-term (up to 28 days) gentle (below 50 °C) heating.

Green synthesis of CoFe2O4/ZnS composite nanoparticles utilizing Moringa Oleifera for magnetic hyperthermia applications

The development of targeted cancer therapies is crucial to reducing harmful patient side effects. The incorporation of magnetic and fluorescent nanoparticles as heat mediators in magnetic hyperthermia is a novel and efficient strategy. This study investigated the potential of CoFe2O4/ZnS composite nanoparticles, successfully fabricated using a green synthesis method with Moringa oleifera leaf extract, as magnetic hyperthermia agents. X-ray diffraction spectra demonstrated the existence of the CoFe2O4 cubic spinel ferrite and ZnS cubic zinc-blend phases in the composite nanoparticles. The average particle sizes of CoFe2O4 and CoFe2O4/ZnS were 12 and 17 nm, respectively. The peak at 1406-1411 cm−1 indicated the incorporation of ZnS on the surfaces of the CoFe2O4/ZnS composite nanoparticles through the SO functional group. The UV–visible spectra showed that the bandgap increased from 3.7 to 4.5 eV with increasing ZnS content. Magnetic property studies indicated that the coercivity and saturation magnetization of the CoFe2O4/ZnS composite nanoparticles were lower than those of the CoFe2O4 nanoparticles but still showed ferromagnetic characteristics. Heating properties were investigated by measuring the specific absorption rate (SAR) in an alternating magnetic field at various ZnS contents. The SAR of the CoFe2O4 composite nanoparticles was 85.7 mW/g while that of the CoFe2O4/ZnS composite nanoparticles increased from 87.8 to 132.9 mW/g with increasing ZnS content. Results indicate that green-synthesized CoFe2O4/ZnS composite nanoparticles are promising candidates for magnetic hyperthermia applications in cancer therapy.

Structure and magnetic properties of [formula omitted] bioactive glass-ceramic system for magnetic fluid hyperthermia application

Ferrimagnetic glass-ceramics comprising maghemite crystals were synthesized for magnetic fluid hyperthermia (MFH) usage. The present work is focused on the result of the chemical composition and heat treatment temperature on the magnetic behavior of (60−x)SiO2−(10+x)FeO−20CaO−10Na2O,0≤x≤30 glass-ceramic system. It was observed that with the increasing of FeO from 10 to 40 wt% in the glass-ceramic compound, the percentage of maghemite phase increased. It was also seen that in the low heat treatment temperature (680 °C), by adding iron oxide up to 30 wt%, iron cations acts as a network former, and more than this amount acts as a network modifier. In contrast, iron cations in the same composition range at high temperatures (840 °C), acts as a network modifier. According to the VSM results, the maximum magnetization of glass-ceramics incremented from 0.23 emu/g to 0.30 emu/g with the increase in FeO percentage. It was also observed that with the increment of iron oxide percentage, the morphology of maghemite crystals changed from spherical to dumbbell-shaped.

Therapeutic hyperthermia for the treatment of infection-a narrative review.

Modulating body temperature, mostly through the use of antipyretics, is a commonly employed therapeutic intervention in medical practice. However, emerging evidence suggests that hyperthermia could serve as an adjuvant therapy for patients with infection. We performed a narrative review to explore the application of therapeutic hyperthermia in the treatment of infection. A number of studies have been performed in the pre-antibiotic era, enrolling patients with neurosyphilis and gonococcal infections, with reported cure rates at around 60%-80%. We have outlined the potential molecular and immunological mechanisms explaining the possible beneficial effects of therapeutic hyperthermia. For some pathogens increased temperature exerts a direct negative effect on virulence; however, it is presumed that temperature driven activation of the immune system is probably the most important factor affecting microbial viability. Lastly, we performed a review of modern-era studies where modulation of body temperature has been used as a treatment strategy. In trials of therapeutic hypothermia in patients with infection worse outcomes have been observed in the hypothermia group. Use of antipyretics has not been associated with any improvement in clinical outcomes. In modern-era therapeutic hyperthermia achieved by physical warming has been studied in one pilot trial, and better survival was observed in the hyperthermia group. To conclude, currently there is not enough data to support the use of therapeutic hyperthermia outside clinical trials; however, available studies are in favor of at least a temperature tolerance strategy for non-neurocritical patients.

Numerical Comparison of Active Shielding Techniques for Magnetic Fluid Hyperthermia Application

This study aims to eliminate magnetic field leakage at 100 kHz with active shielding in Magnetic Fluid Hyperthermia (MFH) system. First of all, the structural and operational features of the MFH system were analyzed. Then, the active regions of the coils were determined, graphical results were obtained and the designs were compared with each other. We first simulated the magnetic field distribution of a circular coil active shielding system by the commercial software tool COMSOL Multiphysics. Secondly, a single D-shape shielding was configured in the MFH system and the size and location of the shielding were examined. The magnetic field attenuation percentages of the methods in the x, y, z axes and the target region selected as the representative tumor region were compared. The simulation results show that the shielding ability of the double D-shape shielding type is better in the x and y axes than the other coil types (51.43% for the x-axis and 95.77% for the y-axis). The fact that the attenuation percentage of this shielding type in the target region is 0.0287% is a secondary advantage. It has been observed that the attenuation in the z-axis is higher in other shielding types, but the attenuation percentage in the target region also increases.

Comparison of Microwave Hyperthermia Applicator Designs with Fora Dipole and Connected Array.

In microwave hyperthermia tumor therapy, electromagnetic waves focus energy on the tumor to elevate the temperature above its normal levels with minimal injury to the surrounding healthy tissue. Microwave hyperthermia applicator design is important for the effectiveness of the therapy and the feasibility of real-time application. In this study, the potential of using fractal octagonal ring antenna elements as a dipole antenna array and as a connected array at 2.45 GHz for breast tumor hyperthermia application was investigated. Microwave hyperthermia treatment models consisting of different fractal octagonal ring antenna array designs and a breast phantom are simulated in COMSOL Multiphysics to obtain the field distributions. The antenna excitation phases and magnitudes are optimized using the global particle swarm algorithm to selectively increase the specific absorption rate at the target region while minimizing hot spots in other regions within the breast. Specific absorption rate distributions, obtained inside the phantom, are analyzed for each proposed microwave hyperthermia applicator design. The dipole fractal octagonal ring antenna arrays are comparatively assessed for three different designs: circular, linear, and Cross-array. The 16-antenna dipole array performance was superior for all three 1-layer applicator designs, and no distinct difference was found between 16-antenna circular, linear, or cross arrays. Two-layer dipole arrays have better performance in the deep-tissue targets than one-layer arrays. The performance of the connected array with a higher number of layers exceeds the performance of the dipole arrays in the superficial regions, while they are comparable for deep regions of the breast. The 1-layer 12-antenna circular FORA dipole array feasibility as a microwave hyperthermia applicator was experimentally shown.

Impact of colloidal stabilization of MnZn-ferrite nanoparticles by oleic acid on their magnetothermal properties

Introduction: The development of magnetic agents for magnetic fluid hyperthermia application is a complex task requiring simultaneous optimization of chemical, biomedical, magnetic, and, in particular, thermal properties of magnetic nanoparticles (MNPs). In the majority of papers, the magnetothermal measurements are carried out on bare MNPs suspended in deionized water with subsequent optimization of the required physiological and medical properties, including toxicity and biocompatibility. However, in real hyperthermia practice, the stable fluids or colloids of magnetic MNPs are used, and the colloidal stabilization can significantly modify their magnetic properties, including magnetothermal ones.Methods: This paper is focused on the study of ZnxMn1-xFe2O4 MNPs stabilized by oleic acid/sodium oleate in this context.Results and Discussion: Our research demonstrates the crucial changes in the magnetic properties and magnetothermal response of ZnMn ferrite MNPs after the colloidal stabilization: while bare MNPs demonstrate significant coercivity, nonzero remanent magnetization, and superquadratic dependence of heat generation on the magnetic field amplitude, the magnetic properties of colloidal ZnMn ferrite MNPs are typical for superparamagnetic ones and their magnetothermal response is described by a conventional quadratic dependence on magnetic field amplitude. Various factors such as size distribution, magnetic anisotropy, and interparticle dipole–dipole interaction are considered as the origins of such an impact on magnetic MNPs’ properties.

Efficacy of the low dose apatinib plus deep hyperthermia as third-line or later treatment in HER-2 negative advanced gastric cancer.

Aim: To observe the efficacy of the low dose apatinib plus deep hyperthermia as third-line or later treatment for patients with human epidermal growth factor receptor 2 (HER-2) negative advanced gastric cancer. Methods: 80 eligible patients with HER-2 negative advanced gastric cancer admitted to Jingjiang People's Hospital Affiliated with Yangzhou University-from March 2021 to March 2022 were selected, and they were divided into the control group (n = 40, apatinib) and experimental group (n = 40, apatinib plus deep hyperthermia) on the basis of random number table method. The levels of serum carcinoembryonic antigen (CEA), carbohydrate antigen 199 (CA199), and vascular endothelial growth factor (VEGF) were monitored, and the efficacy of the two groups was analyzed by referring to Karnofsky performance status (KPS), overall survival (OS) and disease control rate (DCR) before and after treatment. Results: The levels of CEA, CA199, and VEGF in both groups were lower after treatment than before (p < 0.05), and lower (CEA: 8.85 ± 1.36 vs. 12.87 ± 1.23, CA199: 34.19 ± 4.68 vs. 50.11 ± 5.73, VEGF: 124.8 ± 18.03 vs. 205.9 ± 19.91) in the experimental group than in the control group (p < 0.05). The DCR and KPS of the patients in the experimental group were significantly higher (DCR: 62.50% vs. 40.00%; KPS: 83.25 ± 1.15 vs. 76.25 ± 1.17) than in the control group (p < 0.05). In survival analysis, patients with control group had shorter OS than the experimental group. (median 5.65 vs. 6.50months; hazard ratio [HR], 1.63 [95% confidence interval (CI) 1.02-2.60], p = 0.0396). Conclusion: The application of low-dose apatinib plus deep hyperthermia for patients with HER-2 negative gastric cancer who failed second-line treatment should be a promising option.

Flexible Graphene Sheet Loaded Curved Patch Applicator for Superficial Hyperthermia Treatment Planning Utilizing Ripple Effect of Armchair and Zigzag Bending

Background: Non-invasive microwave hyperthermia approaches suffer from several limitations, such as maximum energy localization in the target tissue, reduced unwanted hotspots, less penetration time at specific penetration depth, and maximum directivity of applicators. For conformal body structures, curved patch applicators avoid mismatch losses and provide circular polarization to achieve maximum power deposition at the target tissue. At microwave frequencies, graphene also exhibits good absorption properties and utilizing graphene strips on both sides of a curved patch offers potential benefits of enhancement of gain, directional radiation pattern, and suppressed sidelobes. Objective: Designing a flexible graphene sheet-loaded curved patch for a non-invasive microwave hyperthermia applicator resonating at 2.45 GHz is the prime objective of current work. The proposed work is based on utilizing the absorbing properties of graphene sheets with hybrid hexagonal boron nitride (hBN) under various bending conditions on both sides of a curved patch. Methods: Graphene-loaded curved design offers structural flexibility due to the presence of ripples on the surface and their alignment in armchair configuration (ARC) and zigzag configuration (ZGC). The bending flexibility along the two configurations alters the electronic properties and opens the band gap. Thus, the FEM model has been developed for coupling bio-electromagnetic problems of human body phantom with graphene-loaded curved patch applicator by bending it in two different configurations. Results: For both ARC and ZGC antenna design, parameters, such as return loss and realized gain, have been investigated. The proposed design achieved a maximum return loss value of -30 dB and gain of 7.1 dBi for ARC configuration since it provides the maximum difference in valance band and conduction band in band gap structure, while these values are relatively less in the case of ZGC. The implementation of the design on cylindrical body phantom is realized for ARC with a maximum Efield value of 80.2 V/m at a maximum penetration depth of 40 mm. Further simulations are performed for evaluation of penetration time and fractional tissue damage due to necrosis, and it has been observed that 10 W of input power is sufficient to achieve maximum temperature range and tissue necrosis in a duration of 15 minutes. Conclusion: The results show that a curved graphene patch applicator provides a potential solution for targeted heating in hyperthermia applications.

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.