Parameterizing the Effects of Tumor Shape in Magnetic Nanoparticle Thermotherapy Through a Computational Approach

In this work effects of tumor shape on magnetic nanoparticle hyperthermia (MNPH) are investigated and evaluated using four categories (spherical, oblate, prolate, and egg-shape) of tumor models having different morphologies. These tumors have equal volume; however, due to the differences in their shapes, they have different surface areas. The shape of tumors is quantified in terms of shape factor (ζ). Simulations for MNPH are done on the physical model constituting tumor tissue enclosed within the healthy tissue. Magnetic hyperthermia is applied (frequency 150 kHz, and magnetic field amplitude 20.5 kA/m) to all tumor models, for 1 hour, after injection of magnetic nanoparticles (MNPs) at the respective tumor centroids. The distribution of MNPs after injection is considered Gaussian. The governing model (Pennes' bioheat model) of heat transfer in biological media is solved with the finite volume-immersed boundary (FV-IB) method to simulate MNPH. Therapeutic effects are calculated using the Arrhenius tissue damage model, cumulative equivalent minutes at 43°C (CEM 43), and heterogeneity in temperature profiles of the tumors. Results show that the therapeutic effects due to MNPH depend significantly on the shape of a tumor. Tumors with higher shape factors receive less therapeutic effects in comparison to the tumors having lower shape factors. An empirical thermal damage model is also developed to assess the MNPH efficacy in real complex-shaped tumors.

New Prospects in Neutering Male Animals Using Magnetic Nanoparticle Hyperthermia

Controlling populations of free-roaming dogs and cats poses a huge challenge worldwide. Non-surgical neutering strategies for male animals have been long pursued, but the implementation of the procedures developed has remained limited to date. As submitting the testes to high temperatures impairs spermatogenesis, the present study investigated localized application of magnetic nanoparticle hyperthermia (MNH) to the testicles as a potential non-surgical sterilization method for animals. An intratesticular injection of a magnetic fluid composed of manganese-ferrite nanoparticles functionalized with citrate was administered followed by testicle exposure to an alternate magnetic field to generate localized heat. Testicular MNH was highly effective, causing progressive seminiferous tubule degeneration followed by substitution of the parenchyma with stromal tissue and gonadal atrophy, suggesting an irreversible process with few side effects to general animal health.

Numerical Investigation of Ferrofluid Preparation during In-Vitro Culture of Cancer Therapy for Magnetic Nanoparticle Hyperthermia

Recently, in-vitro studies of magnetic nanoparticle (MNP) hyperthermia have attracted significant attention because of the severity of this cancer therapy for in-vivo culture. Accurate temperature evaluation is one of the key challenges of MNP hyperthermia. Hence, numerical studies play a crucial role in evaluating the thermal behavior of ferrofluids. As a result, the optimum therapeutic conditions can be achieved. The presented research work aims to develop a comprehensive numerical model that directly correlates the MNP hyperthermia parameters to the thermal response of the in-vitro model using optimization through linear response theory (LRT). For that purpose, the ferrofluid solution is evaluated based on various parameters, and the temperature distribution of the system is estimated in space and time. Consequently, the optimum conditions for the ferrofluid preparation are estimated based on experimental and mathematical findings. The reliability of the presented model is evaluated via the correlation analysis between magnetic and calorimetric methods for the specific loss power (SLP) and intrinsic loss power (ILP) calculations. Besides, the presented numerical model is verified with our experimental setup. In summary, the proposed model offers a novel approach to investigate the thermal diffusion of a non-adiabatic ferrofluid sample intended for MNP hyperthermia in cancer treatment.

A Perspective on Modelling Metallic Magnetic Nanoparticles in Biomedicine: From Monometals to Nanoalloys and Ligand-Protected Particles

The focus of this review is on the physical and magnetic properties that are related to the efficiency of monometallic magnetic nanoparticles used in biomedical applications, such as magnetic resonance imaging (MRI) or magnetic nanoparticle hyperthermia, and how to model these by theoretical methods, where the discussion is based on the example of cobalt nanoparticles. Different simulation systems (cluster, extended slab, and nanoparticle models) are critically appraised for their efficacy in the determination of reactivity, magnetic behaviour, and ligand-induced modifications of relevant properties. Simulations of the effects of nanoscale alloying with other metallic phases are also briefly reviewed.

Magnetic Nanoparticle Hyperthermia for Cancer Treatment: a Review On Nanoparticle Types and Thermal Analyses

Magnetic nanoparticle hyperthermia (MNH) is a localized cancer treatment which uses an alternating magnetic field to excite magnetic nanoparticles (MNPs) injected into a tumor, causing them to generate heat. Once the temperature of the tumor tissue reaches about 43°C, the cancerous cells die. Different types of MNPs have been studied, including iron oxides with various coatings, Cu-Ni alloys and complex manganese/zinc particles. This paper reviews different types of MNPs and assesses them by magnetization, SAR, and Curie Temperature. We reviewed the achievements and limitations of the works in this field. A major issue with MNH is maintaining effective hyperthermia while preserving healthy tissue. Numerical modeling can predict temperature distribution and safely simulate hyperthermia. The most used bioheat transfer equation is Pennes' equation which includes a term for blood perfusion, an important factor for temperature distribution. While some models safely neglect it, most include blood perfusion term. Some recent models have also included large blood vessels, others used their own heat transfer models. This article reviews the different models and classifies them based on how they address blood flow. A need for studies with realistic tumor shapes was identified. The irregular shape of most tumors could result in less uniform temperature distribution than in the commonly used circular or spherical models. This article aims to identify potential future work to create more realistic tumor models.

Biomaterial-Modified Magnetic Nanoparticles γ-Fe2O3, Fe3O4 Used to Improve the Efficiency of Hyperthermia of Tumors in HepG2 Model

The main treatments for cancer recorded to date include chemotherapy, radiotherapy, and surgery. Although we have achieved great success in treating certain types of tumors, there are still many incurable even with the help of modern treatments. Currently, the principles of magnetic-induction hyperthermia in magnetic nanoparticle hyperthermia are considered an effective treatment for cancer cells. As reported in previous articles, these nanoparticles generate a lot of heat that raises the temperatures of tumors, hence treating the cancer cells. The other significant potential of magnetic nanoparticles is the ability to combine heat and drug release for cancer treatment. However, within the biologically safe range of AC magnetic fields, the lack of induction heating power and the high criteria for biocompatibility in superparamagnetic-nanoparticle hyperthermia agents still make up the key challenges for the successful clinical application of magnetic hyperthermia. In this study, two different types of iron oxide nanoparticles (γ-Fe2O3, Fe3O4) were modified with whey protein isolate (WPI) to form bio-modified superparamagnetic nanoparticles with spherical or diamond-shaped structures and diameters between 20 and 100 nm, which demonstrate excellent stability under different conditions. Adriamycin (ADM) has also been successfully loaded onto these nanoparticles and used in this experiment. In vitro and in vivo experimental studies were performed using these WPI-modified nanoparticles on HepG2 tumor models and mice to assess their bioavailability and biological feasibility. The results prove that these WPI-modified nanoparticles perform satisfactorily in conjunction with hyperthermia to cure tumors completely.