Recommendations for In Vitro and In Vivo Testing of Magnetic Nanoparticle Hyperthermia Combined with Radiation Therapy

A facile, flexible, and multifunctional thermo-chemotherapy system for customized treatment of drug-resistant breast cancer

Anticancer drug resistance invariably emerges and poses a significant barrier to curative therapy for various breast cancers. This results in a lack of satisfactory therapeutic medicine for cancer treatment. Herein, a universal vector system for drug-resistance breast cancer was designed to meet the needs of reversed multidrug resistance, thermo-chemotherapy, and long-term drug release behavior. The vector system comprises polycaprolactone (PCL) nanofiber mesh and magnetic nanoparticles (MNPs). PCL has excellent biocompatibility and electrospinning performance. In this study, MNPs were tailored to be thermogenic in response to an alternating magnetic field (AMF). PCL nanofiber can deliver various chemotherapy drugs, and suitable MNPs encapsulated in the nanofiber can generate hyperthermia and synergistic effect with those chemotherapy drugs. Therefore, a more personalized treatment system can be developed for different breast malignancies. In addition, the PCL nanofiber mesh (NFM) enables sustained release of the drugs for up two months, avoiding the burden on patients caused by repeated administration. Through model drugs doxorubicin (DOX) and chemosensitizers curcumin (CUR), we systematically verified the therapeutic effect of DOX-resistance breast cancer and inhibition of tumor generation in vivo. These findings represent a multifaceted platform of importance for validating strategic reversed MDR in pursuit of promoted thermo-chemotherapeutic outcomes. More importantly, the low cost and excellent safety and efficacy of this nanofiber mesh demonstrate that this can be customized multi-function vector system may be a promising candidate for refractory cancer therapy in clinical.

Nano delivery system for paclitaxel: Recent advances in cancer theranostics

Paclitaxel is one of the most effective chemotherapeutic drugs which processes the obvious curative effect for a broad range of cancers including breast, ovarian, lung, and head & neck cancers. Though some novel paclitaxel-loaded formulations have been developed, the clinical application of the paclitaxel is still limited due to its toxicity and solubility issues. Over the past decades, we have seen rapid advances in applying nanocarriers in paclitaxel delivery systems. The nano-drug delivery systems offer unique advantages in enhancing the aqueous solubility, reducing side effects, increasing permeability, prolonging circulation half-life of paclitaxel. In this review, we summarize recent advances in developing novel paclitaxel-loaded nano delivery systems based on nanocarriers. These nanocarriers show great potentials in overcoming the disadvantages of pure paclitaxel and as a result improving the efficacy.

Magnetic Iron Nanoparticles: Synthesis, Surface Enhancements, and Biological Challenges

This review focuses on the role of magnetic nanoparticles (MNPs), their physicochemical properties, their potential applications, and their association with the consequent toxicological effects in complex biologic systems. These MNPs have generated an accelerated development and research movement in the last two decades. They are solving a large portion of problems in several industries, including cosmetics, pharmaceuticals, diagnostics, water remediation, photoelectronics, and information storage, to name a few. As a result, more MNPs are put into contact with biological organisms, including humans, via interacting with their cellular structures. This situation will require a deeper understanding of these particles’ full impact in interacting with complex biological systems, and even though extensive studies have been carried out on different biological systems discussing toxicology aspects of MNP systems used in biomedical applications, they give mixed and inconclusive results. Chemical agencies, such as the Registration, Evaluation, Authorization, and Restriction of Chemical substances (REACH) legislation for registration, evaluation, and authorization of substances and materials from the European Chemical Agency (ECHA), have held meetings to discuss the issue. However, nanomaterials (NMs) are being categorized by composition alone, ignoring the physicochemical properties and possible risks that their size, stability, crystallinity, and morphology could bring to health. Although several initiatives are being discussed around the world for the correct management and disposal of these materials, thanks to the extensive work of researchers everywhere addressing the issue of related biological impacts and concerns, and a new nanoethics and nanosafety branch to help clarify and bring together information about the impact of nanoparticles, more questions than answers have arisen regarding the behavior of MNPs with a wide range of effects in the same tissue. The generation of a consolidative framework of these biological behaviors is necessary to allow future applications to be manageable.

Comparative heating efficiency and cytotoxicity of magnetic silica nanoparticles for magnetic hyperthermia treatment on human breast cancer cells

Magnetic hyperthermia (MHT) is a promising treatment for a variety of cancers due to its ability to increase the sensitivity of cells to other treatments, such as chemotherapy. Superparamagnetic nanoparticles (MNPs) were used for MHT treatment due to their heat generation ability under an AC magnetic field (AMF). In this study, iron oxide and zinc-doped iron oxide MNPs were produced and modified with silica to obtain eleven different types (MSNP-I to -XI) of magnetic silica nanoparticles (MSNPs). The MSNPs which show the highest heating capacity were selected to investigate their MHT ability on non-tumourigenic MCF-10A and tumourigenic MCF-7 cell lines. The cytotoxicity results indicated that the size, the content of the magnetic core and silica coating thickness were important in the heating capacity of MSNPs under AMF. After MHT treatment, selected MSNPs showed limited cytotoxicity on MCF-10A, but significant cell death on MCF-7.

Supplementary Information

The online version contains supplementary material available at 10.1007/s13205-022-03377-y.

Fe3O4-PAA–(HP-γ-CDs) Biocompatible Ferrimagnetic Nanoparticles for Increasing the Efficacy in Superparamagnetic Hyperthermia

In this paper, we present the obtaining of Fe3O4-PAA–(HP-γ-CDs) ferrimagnetic nanobioconjugates (PAA: polyacrylic acid, HP-γ-CDs: hydroxypropyl gamma-cyclodextrins) in a hybrid core-shell biostructure (core: inorganic Fe3O4 nanoparticles, and shell: organic PAA–(HP-γ-CDs)) and their use in superparamagnetic hyperthermia without cellular toxicity and with increased efficacy for future alternative cancer therapy. In order to design the optimal experimental conditions for obtaining nanobioconjugates and then superparamagnetic hyperthermia (SPMHT), we used molecular docking simulation and computational assessment of the maximum specific loss power (SLP) that led to nanoparticles’ heating. The nanoparticles and nanobioconjugates obtained were studied and characterized by X-ray diffraction (XRD), transmission electron microscopy (TEM), Fourier transformed-infrared spectroscopy (FT-IR), dynamic light scattering (DLS), and magnetic measurements (MMs). The cell viability of the nanoparticles and nanobioconjugates was assessed by means of the MTT assay using human immortalized keratinocytes (HaCaT) as an in vitro model. Superparamagnetic hyperthermia with nanoparticles and nanobioconjugates was obtained experimentally in a magnetic field of 15.92 kA/m and frequency of 312.2 kHz for the magnetic nanoparticle core with a (average) diameter of 15.8 nm, which resulted in the maximum hyperthermic effect that led to a temperature of ~42.5 °C necessary in the therapy of tumors in a short time so as not to affect healthy tissues. The biological screening of Fe3O4-PAA nanoparticles and PAA–(HP-γ-CDs) nanobioconjugates showed no cytotoxic effect on HaCaT cells for a time interval of 24 h, both under standard (37 °C) and hyperthermia conditions (42.5 °C). Thus, Fe3O4-PA–(HP-γ-CDs) ferrimagnetic nanobioconjugates can be used successfully in superparamagnetic hyperthermia without toxicity and with increased efficiency due to the small layer thickness of the PAA–(HP-γ-CDs) shell, which is suitable in this alternative therapeutic technique.

90Y-CA/SPIONs for dual magnetic hyperthermia-radionuclide nanobrachytherapy of solid tumours

Radiolabelled superparamagnetic iron oxide nanoparticles (SPIONs) are a promising nanomaterial for the development of dual radiation/hyperthermia cancer therapy. To that purpose, flower-shaped SPIONs with an exceptional heating capability were synthesised and coated with citrate, dextran or (3-aminopropyl)triethoxysilane. Both non-coated and coated SPIONs were nontoxic to CT-26 mouse colon cancer cells up to 1.0 mg ml^-1in vitro. In an oscillating magnetic field, citrate-coated SPIONs (CA/SPIONs) displayed the highest heating rate (SAR ∼ 253 W g^-1) and the strongest hyperthermia effects against CT-26 cells. Labelling of the CA/SPIONs by the⁹⁰Y radionuclide, emitting β^-radiation with an average/maximum energy of 0.94/2.23 MeV, and deep tissue penetration generated⁹⁰Y-CA/SPIONs intended for the therapy of solid tumours. However, intravenous injection of⁹⁰Y-CA/SPIONs in CT-26 xenograft-bearing mice resulted in low tumour accumulation. On the contrary, intratumoural injection resulted in long-term retention at the injection site. A single intratumoural injection of 0.25 mg CA/SPIONs followed by 30-min courses of magnetic hyperthermia for four consecutive days caused a moderate antitumour effect against CT-26 and 4T1 mouse tumour xenografts. Intratumoural application of 1.85 MBq/0.25 mg⁹⁰Y-CA/SPIONs, alone or combined with hyperthermia, caused a significant (P ≤ 0.01) antitumour effect without signs of systemic toxicity. The results confirm the suitability of⁹⁰Y-CA/SPIONs for monotherapy or dual magnetic hyperthermia-radionuclide nanobrachytherapy (NBT) of solid tumours.

Iron oxide nanoflowers encapsulated in thermosensitive fluorescent liposomes for hyperthermia treatment of lung adenocarcinoma

Magnetic hyperthermia (MHT) is in the spotlight of nanomedical research for the treatment of cancer employing magnetic iron oxide nanoparticles and their intrinsic capability for heat dissipation under an alternating magnetic field (AMF). Herein we focus on the synthesis of iron oxide nanoflowers (Nfs) of different sizes (15 and 35 nm) and coatings (bare, citrate, and Rhodamine B) while comparing their physicochemical and magnetothermal properties. We encapsulated colloidally stable citrate coated Nfs, of both sizes, in thermosensitive liposomes via extrusion, and RhB was loaded in the lipid bilayer. All formulations proved hemocompatible and cytocompatible. We found that 35 nm Nfs, at lower concentrations than 15 nm Nfs, served better as nanoheaters for magnetic hyperthermia applications. In vitro, magnetic hyperthermia results showed promising therapeutic and imaging potential for RhB loaded magnetoliposomes containing 35 nm Nfs against LLC and CULA cell lines of lung adenocarcinoma.

Magnetic Nanomaterials for Arterial Embolization and Hyperthermia of Parenchymal Organs Tumors: A Review

Magnetic hyperthermia (MH), proposed by R. K. Gilchrist in the middle of the last century as local hyperthermia, has nowadays become a recognized method for minimally invasive treatment of oncological diseases in combination with chemotherapy (ChT) and radiotherapy (RT). One type of MH is arterial embolization hyperthermia (AEH), intended for the presurgical treatment of primary inoperable and metastasized solid tumors of parenchymal organs. This method is based on hyperthermia after transcatheter arterial embolization of the tumor’s vascular system with a mixture of magnetic particles and embolic agents. An important advantage of AEH lies in the double effect of embolotherapy, which blocks blood flow in the tumor, and MH, which eradicates cancer cells. Consequently, only the tumor undergoes thermal destruction. This review introduces the progress in the development of polymeric magnetic materials for application in AEH.

Evaluation of the in vivo acute toxicity of poly(thioether-ester) and superparamagnetic poly(thioether-ester) nanoparticles obtained by thiol-ene miniemulsion polymerization

Poly(thioether-ester) (PTEe) nanoparticles obtained by thiol-ene polymerization have received attention of many researchers due to several advantages, including, biocompatibility and biodegradability. The search for new nanomaterials requires toxicity studies to assess potential toxic effects of their administration. Therefore, the aim of this study was to evaluate the in vivo acute toxicity of PTEe and poly(thioether-ester)-coated magnetic nanoparticles prepared by thiol-ene polymerization in miniemulsion. These nanoparticles presented a mean size of approximately 120 nm, spherical morphology, and negative surface charge. Doses of 40 mg/kg were administered intraperitoneally to Swiss mice and nociceptive, behavioral and biochemical parameters were investigated in five different organs. None of the nanoparticles led to any alterations in the nociceptive and behavioral responses. Biochemical alterations were observed in liver, decreasing the sulfhydryl and glutathione (GSH) levels, suggesting the dependence of the GSH metabolism in the elimination of the nanoparticles. In general, both nanoparticle types did not cause disturbances in biochemical parameters analyzed in others organs. These results suggest that both nanoparticle types did not induce acute toxicity to the different organs evaluated, reinforcing the biocompatibility of PTEe nanoparticles synthetized by thiol-ene polymerization.

Poly(ethylene-imine)-Functionalized Magnetite Nanoparticles Derivatized with Folic Acid: Heating and Targeting Properties

Magnetite nanoparticles (MNPs) coated by branched poly (ethylene-imine) (PEI) were synthesized in a one-pot. Three molecular weights of PEI were tested, namely, 1.8 kDa (sample MNP-1), 10 kDa (sample MNP-2), and 25 kDa (sample MNP-3). The MNP-1 particles were further functionalized with folic acid (FA) (sample MNP-4). The four types of particles were found to behave magnetically as superparamagnetic, with MNP-1 showing the highest magnetization saturation. The particles were evaluated as possible hyperthermia agents by subjecting them to magnetic fields of 12 kA/m strength and frequencies ranging between 115 and 175 kHz. MNP-1 released the maximum heating power, reaching 330 W/g at the highest frequency, in the high side of reported values for spherical MNPs. In vitro cell viability assays of MNP-1 and MNP-4 against three cell lines expressing different levels of FA receptors (FR), namely, HEK (low expression), and HeLa (high expression), and HepG2 (high expression), demonstrated that they are not cytotoxic. When the cells were incubated in the presence of a 175 kHz magnetic field, a significant reduction in cell viability and clone formation was obtained for the high expressing FR cells incubated with MNP-4, suggesting that MNP-4 particles are good candidates for magnetic field hyperthermia and active targeting.

Bioevaluation of glucose-modified liposomes as a potential drug delivery system for cancer treatment using 177-Lu radiotracking

Liposomes are promising drug's delivery systems due to decreased toxicity of the liposome-encapsulated drug, but wider clinical application requires their more efficient tumor targeting with uptake, controlled drug release and higher shelf life. The unique metabolic characteristics of cancer cells based on higher demand for energy and therefore increased glucose utilization were exploited in the design of glucose modified liposomes (GML) with the aim to provide increased tumor targeting via glucose transporters and increased ability of drug delivery into tumor cells. Tumor accumulating potential of GML and non-glucose liposomes (NGL) were investigated on CT26 and LS174T tumor-bearing mice by simple and reliable radiotracer method using ¹⁷⁷Lu as radioactive marker. Both liposomes, GML and NGL were radiolabeled in high radiolabeling yield, showing high in vitro stability in biological media, as the main prerequisite for the biodistribution studies. Tumors displayed significantly better accumulation of ¹⁷⁷Lu-GML with the maximum uptake 6 h post-injection (5.8 ± 0.2%/g in LS174T tumor and 5.1 ± 0.5%/g in CT26 tumor), compared to negligible uptake of ¹⁷⁷Lu-NGL (0.6 ± 0.1%/g in LS174T tumor and 0.9 ± 0.2%/g in CT26 tumor). Results of comparative biodistribution studies of ¹⁷⁷Lu-NGL and ¹⁷⁷Lu-GML indicate that increased accumulation of GML is enabled by glucose transporters and subsequent endocytosis, resulting in their prolonged retention in tumor tissues (up to 72 h). Direct radiolabeling of liposomes with ¹⁷⁷Lu may be used not only for biodistribution studies using radiotracking, but also for cancer treatment.

Rapid tumor inhibition via magnetic hyperthermia regulated by caspase 3 with time-dependent clearance of iron oxide nanoparticles

Among conventional cancer therapies, radio-frequency magnetic hyperthermia (MHT) has widely been investigated for use with magnetic nanoparticles (MNPs). However, the majority of in vivo biodistribution studies have tested very low MNP dosages (equivalent to magnetic resonance imaging (MRI) applications) to check for clearance rate; which is far below the clinical dose of MHT. Due to this poor validation in preclinical scenarios, quite a few MNPs already in clinical use were later discontinued, on grounds of unexpected clinical outcomes in terms of inflammation, and prolonged clearance in vivo. By exploiting an economical method of synthesis, we have developed chitosan-coated Fe₃O₄ nanoparticles with high heating efficiency performance. Their anti-tumor response was evaluated in an ectopic tumor model of C6 glioblastoma by MHT. The intratumoral injection of MNPs on days 1 and 7 resulted in rapid tumor inhibition rate of 69.4% within 8 days, with complete inhibition within 32 days, and no recurrence recorded over a 5-month follow-up. Notably, the MNP-mediated MHT therapy achieved the highest degree of therapeutic efficacy required for complete tumor ablation by combining controlled temperature range (<44 °C), reduced MNP dosage; much lower than in most reported studies, and AMF parameters (time of exposure and frequency) within the clinical safety limit. Periodic body weight measurements confirmed negligible adverse side effects in rats. The anti-tumor activity was validated by severe apoptosis (TUNEL, cleaved Caspase-3), reduced proliferation (Ki 67) and disrupted vasculature (CD 31) in the Fe₃O₄-MHT-treated group. Real-time gene expression of pro-inflammatory cytokines (IL-6, TNF-α, IL-1α, IL-1β) confirmed the intratumoral activation of IL-6, suggesting the role of immunomodulation in triggering the adaptive immune response for faster tumor regression in the treated group. In addition, the biodistribution and clearance rate of MNPs monitored using ICP-OES confirmed their time-dependent biodegradation via excretion (urine, feces), phagocytosis (liver) and circulatory system (blood), with negligible deposition in other major organs (kidney, heart, lungs). Although we could not show complete clearance of our MNPs within the time frame tested, future studies should focus on combining MHT with immunotherapy, and target tumors at a much-reduced iron dose, consequently improving in vivo clearance rate, and hence overcoming the limitations of MHT in clinical therapy.

Disturbance of cellular homeostasis as a molecular risk evaluation of human endothelial cells exposed to nanoparticles

Even though application of nanoparticles in medicine seems to provide unique solutions for drug delivery and diagnosis diseases, understanding interactions between nanoscale materials and biological systems is imperative. Therefore, this study determined the effect of different types of nanoparticles (NPs) on human endothelial cells and examined the types of toxicity responses they can induce. Four different types of NPs were tested (PLA/MMT/TRASTUZUMAB, PLA/EDTMP, PLGA/MDP, and Pluronic F127 MICELLES), representing three putative areas of application: anticancer therapy, scintigraphy, and cosmetology. The experiments were performed on immortalized human umbilical vein endothelial cells (HUVEC-STs). Light contrast phase microscopy as well as cell viability assays showed that only Pluronic F127 MICELLES decreased the number of HUVEC-STs in contrast to PLA/MMT/TRASTUZUMAB, PLA/EDTMP, and PLGA/MDP NPs, which altered cell morphology, but not their confluency. The tested NPs induced not only DNA strand-breaks and alkali-labile sites, but also internucleosomal DNA fragmentation, visualized as a DNA ladder pattern typical of apoptosis. Moreover, generation of free radicals and subsequent mitochondrial membrane potential collapse showed the significance of free radical production during interactions between NPs and endothelial cells. High concentrations of NPs had different degrees of toxicity in human endothelial cells and affected cell proliferation, redox homeostasis, and triggered mitochondrial dysfunction.

Micron-sized iron oxide particles for both MRI cell tracking and magnetic fluid hyperthermia treatment

Iron oxide particles (IOP) are commonly used for Cellular Magnetic Resonance Imaging (MRI) and in combination with several treatments, like Magnetic Fluid Hyperthermia (MFH), due to the rise in temperature they provoke under an Alternating Magnetic Field (AMF). Micrometric IOP have a high sensitivity of detection. Nevertheless, little is known about their internalization processes or their potential heat power. Two micrometric commercial IOP (from Bangs Laboratories and Chemicell) were characterized by Transmission Electron Microscopy (TEM) and their endocytic pathways into glioma cells were analyzed. Their Specific Absorption Rate (SAR) and cytotoxicity were evaluated using a commercial AMF inductor. T2-weighted imaging was used to monitor tumor growth in vivo after MFH treatment in mice. The two micron-sized IOP had similar structures and r2 relaxivities (100 mM-1 s-1) but involved different endocytic pathways. Only ScreenMAG particles generated a significant rise in temperature following AMF (SAR = 113 W g-1 Fe). After 1 h of AMF exposure, 60% of ScreenMAG-labeled cells died. Translated to a glioma model, 89% of mice responded to the treatment with smaller tumor volume 42 days post-implantation. Micrometric particles were investigated from their characterization to their intracellular internalization pathways and applied in one in vivo cancer treatment, i.e. MFH.

Synergic effects of nanoparticles-mediated hyperthermia in radiotherapy/chemotherapy of cancer

The conventional cancer treatment modalities such as radiotherapy and chemotherapy suffer from several limitations; hence, their efficiency needs to be improved with other complementary modalities. Hyperthermia, as an adjuvant therapeutic modality for cancer, can result in a synergistic effect on radiotherapy (radiosensitizer) and chemotherapy (chemosensitizer). Conventional hyperthermia methods affect both tumoral and healthy tissues and have low specificity. In addition, a temperature gradient generates in the tissues situated along the path of the heat source, which is a more serious for deep-seated tumors. Nanoparticles (NPs)-induced hyperthermia can resolve these drawbacks through localization around/within tumoral tissue and generating local hyperthermia. Although there are several review articles dealing with NPs-induced hyperthermia, lack of a paper discussing the combination of NPs-induced hyperthermia with the conventional chemotherapy or radiotherapy is tangible. Accordingly, the main focus of the current paper is to summarize the principles of NPs-induced hyperthermia and more importantly its synergic effects on the conventional chemotherapy or radiotherapy. The heat-producing nanostructures such as gold NPs, iron oxide NPs, and carbon NPs, as well as the non-heat-producing nanostructures, such as lipid-based, polymeric, and silica-based NPs, as the carrier for heat-producing NPs, are discussed and their pros and cons highlighted.

Hadron Therapy, Magnetic Nanoparticles and Hyperthermia: A Promising Combined Tool for Pancreatic Cancer Treatment

A combination of carbon ions/photons irradiation and hyperthermia as a novel therapeutic approach for the in-vitro treatment of pancreatic cancer BxPC3 cells is presented. The radiation doses used are 0–2 Gy for carbon ions and 0–7 Gy for 6 MV photons. Hyperthermia is realized via a standard heating bath, assisted by magnetic fluid hyperthermia (MFH) that utilizes magnetic nanoparticles (MNPs) exposed to an alternating magnetic field of amplitude 19.5 mTesla and frequency 109.8 kHz. Starting from 37 °C, the temperature is gradually increased and the sample is kept at 42 °C for 30 min. For MFH, MNPs with a mean diameter of 19 nm and specific absorption rate of 110 ± 30 W/g_Fe3o₄ coated with a biocompatible ligand to ensure stability in physiological media are used. Irradiation diminishes the clonogenic survival at an extent that depends on the radiation type, and its decrease is amplified both by the MNPs cellular uptake and the hyperthermia protocol. Significant increases in DNA double-strand breaks at 6 h are observed in samples exposed to MNP uptake, treated with 0.75 Gy carbon-ion irradiation and hyperthermia. The proposed experimental protocol, based on the combination of hadron irradiation and hyperthermia, represents a first step towards an innovative clinical option for pancreatic cancer.

In vitro Biological Tests as the First Tools To Validate Magnetic Nanotheranostics for Colorectal Cancer Models

Colorectal cancer (CRC) remains a leading cause of cancer death. Nanotechnology has focused on reaching more effective treatments. In this concern, magnetic nanoparticles (MNPs) have been studied for a wide range of biomedical applications related to CRC, such as diagnostic imaging, drug delivery and thermal therapy. However, limited research is currently found in the open literature that refers to nanosystems combining all these mentioned areas (theranostics). When developing nanosystems intended as theranostics applied to CRC, possible variations between patients must be considered. Therefore, multiple in vitro assays are required as guidance for future preclinical and clinical trials. The objective of this contribution is to evaluate the available and recent literature regarding the interactions of MNP and CRC models, aiming to critically analyze the information given by the commonly used assays and evaluate the data provided by each one with a view to implementing this novel technology in CRC diagnostics and therapy.

Integrating Loco-Regional Hyperthermia Into the Current Oncology Practice: SWOT and TOWS Analyses

Moderate hyperthermia at temperatures between 40 and 44°C is a multifaceted therapeutic modality. It is a potent radiosensitizer, interacts favorably with a host of chemotherapeutic agents, and, in combination with radiotherapy, enforces immunomodulation akin to “in situ tumor vaccination.” By sensitizing hypoxic tumor cells and inhibiting repair of radiotherapy-induced DNA damage, the properties of hyperthermia delivered together with photons might provide a tumor-selective therapeutic advantage analogous to high linear energy transfer (LET) neutrons, but with less normal tissue toxicity. Furthermore, the high LET attributes of hyperthermia thermoradiobiologically are likely to enhance low LET protons; thus, proton thermoradiotherapy would mimic ¹²C ion therapy. Hyperthermia with radiotherapy and/or chemotherapy substantially improves therapeutic outcomes without enhancing normal tissue morbidities, yielding level I evidence reported in several randomized clinical trials, systematic reviews, and meta-analyses for various tumor sites. Technological advancements in hyperthermia delivery, advancements in hyperthermia treatment planning, online invasive and non-invasive MR-guided thermometry, and adherence to quality assurance guidelines have ensured safe and effective delivery of hyperthermia to the target region. Novel biological modeling permits integration of hyperthermia and radiotherapy treatment plans. Further, hyperthermia along with immune checkpoint inhibitors and DNA damage repair inhibitors could further augment the therapeutic efficacy resulting in synthetic lethality. Additionally, hyperthermia induced by magnetic nanoparticles coupled to selective payloads, namely, tumor-specific radiotheranostics (for both tumor imaging and radionuclide therapy), chemotherapeutic drugs, immunotherapeutic agents, and gene silencing, could provide a comprehensive tumor-specific theranostic modality akin to “magic (nano)bullets.” To get a realistic overview of the strength (S), weakness (W), opportunities (O), and threats (T) of hyperthermia, a SWOT analysis has been undertaken. Additionally, a TOWS analysis categorizes future strategies to facilitate further integration of hyperthermia with the current treatment modalities. These could gainfully accomplish a safe, versatile, and cost-effective enhancement of the existing therapeutic armamentarium to improve outcomes in clinical oncology.

Magnetism in drug delivery: The marvels of iron oxides and substituted ferrites nanoparticles

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The conventional utilization of drugs is characterized by poor biodistribution, limited effectiveness, and lack of selectivity, besides undesirable side effects on multiple body systems.

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Seeking a DDS with a modifiable skeleton to customize drug targeting is of extreme importance for successful therapy of many diseases.

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Among the different synthesis strategies for MNPs, chemical methods are the most common, and on top of the pyramid, is the co-precipitation method.

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MNPs have customizable properties, where applying a hydrophilic coating protects the particles from opsonization and human-immunity recognition, which increases their circulation time.

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The route MNPs usually follow in the body starts with magnetic guidance to the target, immobilization for drug release, and finally clearance.

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Interestingly, multifunctional nanocomplexes with conjugated SPIONS and PEI presented enhanced transfection while decreased PEI toxicity.

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Theranostic applications of MNPs are limitless, whether it is a dual function of diagnosis and therapy simultaneously, or a multimodal imaging system.

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IONPs participate in the production of oxidative stress that leads to cell damage.

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Metal ferrite NPs can overcome the drawbacks of IONPs provided that the substituting metal in use is less toxic.

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Metal ferrite NPs present unique properties of high saturation magnetization, enhanced encapsulation efficacy, as well as enzyme-mimetic activities.

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Magnesium ferrite NPs (MFNPs) were found to exhibit greater magnetic heating capacity compared to other ferrites. MFNPs also show safe metabolism and high biocompatibility, making them a promising system for cancer applications.

In modern drug delivery, seeking a drug delivery system (DDS) with a modifiable skeleton for proper targeting of loaded actives to specific sites in the body is of extreme importance for a successful therapy. Magnetically guided nanosystems, where particles such as iron oxides are guided to specific regions using an external magnetic field, can provide magnetic resonance imaging (MRI) while delivering a therapeutic payload at the same time, which represents a breakthrough in disease therapy and make MNPs excellent candidates for several biomedical applications. In this review, magnetic nanoparticles (MNPs) along with their distinguishable properties, including pharmacokinetics and toxicity, especially in cancer therapy will be discussed. The potential perspective of using other elements within the MNP system to reduce toxicity, improve pharmacokinetics, increase the magnetization ability, improve physical targeting precision and/or widen the scope of its biomedical application will be also discussed.

Polyol-Made Luminescent and Superparamagnetic β-NaY0.8Eu0.2F4@γ-Fe2O3 Core-Satellites Nanoparticles for Dual Magnetic Resonance and Optical Imaging

Red luminescent and superparamagnetic β-NaY0.8Eu0.2F4@γ-Fe2O3 nanoparticles, made of a 70 nm-sized β-NaY0.8Eu0.2F4 single crystal core decorated by a 10 nm-thick polycrystalline and discontinuous γ-Fe2O3 shell, have been synthesized by the polyol process. Functionalized with citrate ligands they show a good colloidal stability in water making them valuable for dual magnetic resonance and optical imaging or image-guided therapy. They exhibit a relatively high transverse relaxivity r2 = 42.3 mM-1·s-1 in water at 37 °C, for an applied static magnetic field of 1.41 T, close to the field of 1.5 T applied in clinics, as they exhibit a red emission by two-photon excited fluorescence microscopy. Finally, when brought into contact with healthy human foreskin fibroblast cells (BJH), for doses as high as 50 µg·mL-1 and incubation time as long as 72 h, they do not show evidence of any accurate cytotoxicity, highlighting their biomedical applicative potential.

Therapeutic Efficiency of Multiple Applications of Magnetic Hyperthermia Technique in Glioblastoma Using Aminosilane Coated Iron Oxide Nanoparticles: In Vitro and In Vivo Study

Magnetic hyperthermia (MHT) has been shown as a promising alternative therapy for glioblastoma (GBM) treatment. This study consists of three parts: The first part evaluates the heating potential of aminosilane-coated superparamagnetic iron oxide nanoparticles (SPIONa). The second and third parts comprise the evaluation of MHT multiple applications in GBM model, either in vitro or in vivo. The obtained heating curves of SPIONa (100 nm, +20 mV) and their specific absorption rates (SAR) stablished the best therapeutic conditions for frequencies (309 kHz and 557 kHz) and magnetic field (300 Gauss), which were stablished based on three in vitro MHT application in C6 GBM cell line. The bioluminescence (BLI) signal decayed in all applications and parameters tested and 309 kHz with 300 Gauss have shown to provide the best therapeutic effect. These parameters were also established for three MHT applications in vivo, in which the decay of BLI signal correlates with reduced tumor and also with decreased tumor glucose uptake assessed by positron emission tomography (PET) images. The behavior assessment showed a slight improvement after each MHT therapy, but after three applications the motor function displayed a relevant and progressive improvement until the latest evaluation. Thus, MHT multiple applications allowed an almost total regression of the GBM tumor in vivo. However, futher evaluations after the therapy acute phase are necessary to follow the evolution or tumor total regression. BLI, positron emission tomography (PET), and spontaneous locomotion evaluation techniques were effective in longitudinally monitoring the therapeutic effects of the MHT technique.

In vitro exploration of the synergistic effect of alternating magnetic field mediated thermo–chemotherapy with doxorubicin loaded dual pH- and thermo-responsive magnetic nanocomposite carriers

Nanoparticle induced hyperthermia has been considered as a promising approach for cancer treatment for decades.

Magnetic nanoparticles in nanomedicine: a review of recent advances

Nanomaterials, in addition to their small size, possess unique physicochemical properties that differ from bulk materials, making them ideal for a host of novel applications. Magnetic nanoparticles (MNPs) are one important class of nanomaterials that have been widely studied for their potential applications in nanomedicine. Due to the fact that MNPs can be detected and manipulated by remote magnetic fields, it opens a wide opportunity for them to be used in vivo. Nowadays, MNPs have been used for diverse applications including magnetic biosensing (diagnostics), magnetic imaging, magnetic separation, drug and gene delivery, and hyperthermia therapy, etc. Specifically, we reviewed some emerging techniques in magnetic diagnostics such as magnetoresistive (MR) and micro-Hall (μHall) biosensors, as well as the magnetic particle spectroscopy, magnetic relaxation switching and surface enhanced Raman spectroscopy (SERS)-based bioassays. Recent advances in applying MNPs as contrast agents in magnetic resonance imaging and as tracer materials in magnetic particle imaging are reviewed. In addition, the development of high magnetic moment MNPs with proper surface functionalization has progressed exponentially over the past decade. To this end, different MNP synthesis approaches and surface coating strategies are reviewed and the biocompatibility and toxicity of surface functionalized MNP nanocomposites are also discussed. Herein, we are aiming to provide a comprehensive assessment of the state-of-the-art biological and biomedical applications of MNPs. This review is not only to provide in-depth insights into the different synthesis, biofunctionalization, biosensing, imaging, and therapy methods but also to give an overview of limitations and possibilities of each technology.

Principles of Magnetic Hyperthermia: A Focus on Using Multifunctional Hybrid Magnetic Nanoparticles

Hyperthermia is a noninvasive method that uses heat for cancer therapy where high temperatures have a damaging effect on tumor cells. However, large amounts of heat need to be delivered, which could have negative effects on healthy tissues. Thus, to minimize the negative side effects on healthy cells, a large amount of heat must be delivered only to the tumor cells. Magnetic hyperthermia (MH) uses magnetic nanoparticles particles (MNPs) that are exposed to alternating magnetic field (AMF) to generate heat in local regions (tissues or cells). This cancer therapy method has several advantages, such as (a) it is noninvasive, thus requiring surgery, and (b) it is local, and thus does not damage health cells. However, there are several issues that need to achieved: (a) the MNPs should be biocompatible, biodegradable, with good colloidal stability (b) the MNPs should be successfully delivered to the tumor cells, (c) the MNPs should be used with small amounts and thus MNPs with large heat generation capabilities are required, (d) the AMF used to heat the MNPs should meet safety conditions with limited frequency and amplitude ranges, (e) the changes of temperature should be traced at the cellular level with accurate and noninvasive techniques, (f) factors affecting heat transport from the MNPs to the cells must be understood, and (g) the effect of temperature on the biological mechanisms of cells should be clearly understood. Thus, in this multidisciplinary field, research is needed to investigate these issues. In this report, we shed some light on the principles of heat generation by MNPs in AMF, the limitations and challenges of MH, and the applications of MH using multifunctional hybrid MNPs.

Preparation and Characterization of Fe3O4@MTX Magnetic Nanoparticles for Thermochemotherapy of Primary Central Nervous System Lymphoma in vitro and in vivo

Background

Primary central nervous system lymphomas (PCNSL) are extranodal malignant non-Hodgkin lymphomas (NHL) that arise exclusively in central nervous system (CNS). Diffuse large B-cell lymphoma (DLBCL) is the most common histological subtype.

Purpose

To evaluate whether nano drug-loading system-mediated magnetic-targeted thermochemotherapy could produce a better therapeutic effect than single chemotherapy while reducing the use of chemotherapeutic drugs.

Methods

Six groups (control, Fe₃O₄, MTX, Fe₃O₄@MTX, Fe₃O₄ with hyperthermia and Fe₃O₄@MTX with hyperthermia) were set. Tumor cell apoptosis in each treatment group was detected by flow cytometry. Apoptosis-related gene expressions Caspase-3, Bax and Bcl-2 were detected by qPCR and Western blot; intracranial tumor model of PCNSL was established by intracranial injection of OCI-LY18 tumor cells into BALB/c-Nude mice. Magnetic resonance imaging (MRI) was used to monitor tumor progression and H&E staining was used to observe pathological changes of the tumor tissue.

Results

In vitro, compared with chemotherapy alone, apoptosis rate of Fe₃O₄@MTX mediated thermochemotherapy group was significantly increased, and expression of apoptosis-inducing gene Caspase-3 and Bax were significantly upregulated in OCI-LY18 cells, while expression of apoptosis-inhibiting Bcl-2 gene was significantly downregulated. In vivo, MRI showed successful generation of intracranial tumor, and tumor volume was significantly smaller in combined thermochemotherapy group than in single chemotherapy group. H&E staining result of tumor tissues in each group was consistent with MRI; tumor cells were significantly reduced in thermochemotherapy group. Expression of apoptosis-related gene Caspase-3 and Bax were significantly upregulated in tumor tissues, while expression of Bcl-2 gene was significantly downregulated.

Conclusion

These results demonstrated in vivo and in vitro that the combined thermochemotherapy of Fe₃O₄@MTX MNPs was superior to the single MTX chemotherapy with less dosage, which may promote apoptosis of DLBCL cells through the mitochondrial apoptotic pathway and provided a new way for the treatment of PCNSL.

Thermal monitoring during photothermia: hybrid probes for simultaneous plasmonic heating and near-infrared optical nanothermometry

The control of temperature during photothermal therapy is key to preventing unwanted damage in surrounding tissue or post-treatment inflammatory responses. Lack of accurate thermal control is indeed one of the main limitations that hyperthermia techniques present to allow their translation into therapeutic applications. We developed a nanoprobe that allows controlled local heating, combined with in situ nanothermometry. The design of the probe follows a practical rationale that aims at simplifying experimental requirements and exploits exclusively optical wavelengths matching the first and second biological windows in the near-infrared. Methods: Hybrid nanostructures were chemically synthesized, and combine gold nanostars (photothermal agents) with CaF₂:Nd³⁺,Y³⁺ nanoparticles (luminescent nanothermometers). Both components were simultaneously excited in the near-infrared range, at 808 nm. Following the goal of simplifying the thermal monitoring technique, the luminescent signal was recorded with a portable near-infrared detector. The performance of the probes was tested in 3D tumor spheroids from a human glioblastoma (U87MG) cell line. The location of the beads within the spheroids was determined measuring Nd³⁺ emission in a commercial Lightsheet microscope, modified in-house to be able to select the required near-infrared wavelengths. The temperature achieved inside the tumor spheroids was deduced from the luminescence of Nd³⁺, following a protocol that we developed to provide reliable thermal readings. Results: The choice of materials was shown to work as an optically excited hybrid probe. Depending on the illumination parameters, temperature can be controlled in a range between 37 ºC and 100 ºC. The near-infrared emission of nanothermometers also allows microscopic tracking of the hybrid nanostructures, confirming that the probes can penetrate deeper into the spheroid mass. We observed that, application of optical thermometry in biological environments requires often neglected considerations, since the optical signal changes along the optical path. Accordingly, we developed data analysis protocols that guarantee reliable thermal readings. Conclusions: The prepared hybrid probes are internalized in 3D tumor spheroids and can be used to induce cell death through photothermal effects, while simultaneously measuring the local temperature in situ. We show that luminescent thermometry in biomedical applications requires the development of protocols that guarantee accurate readings. Regarding photothermal treatments, we observe a sharp thermal threshold at around 55 ºC (for 10 min treatments) that separates high survival ratio from complete cell death.

Nanophosphor-Based Contrast Agents for Spectral X-ray Imaging

Lanthanide-based nanophosphors (NPhs) are herein developed as contrast agents for spectral X-ray imaging, highlighting the chemical, macromolecular and structural differences derived from ligand exchange on computed tomography (CT) and solvent dispersibility. Taking advantage of the ability of spectral X-ray imaging with photon-counting detectors to perform image acquisition, analysis, and processing at different energy windows (bins), enhanced signal of our K-edge materials was derived, improving sensitivity of CT imaging, and differentiation between water, tumor-mimic phantoms, and contrast materials. Our results indicate that the most effective of our oleic acid-stabilized K-edge nanoparticles can achieve 2-4x higher contrast than the examined iodinated molecules, making them suitable for deep tissue imaging of tissues or tumors. On the other hand, ligand exchange yielding poly(acrylic acid)-stabilized K-edge nanoparticles allows for high dispersibility and homogeneity in water, but with a lower contrast due to the high density of the polymer grafted, unless further engineering is probed. This is the first well-defined study that manages to correlate NPh grafting density with CT numbers and water dispersibility, laying the groundwork for the development of the next generation CT-guided diagnostic and/or theranostic materials.

Paclitaxel Magnetic Core⁻Shell Nanoparticles Based on Poly(lactic acid) Semitelechelic Novel Block Copolymers for Combined Hyperthermia and Chemotherapy Treatment of Cancer

Magnetic hybrid inorganic/organic nanocarriers are promising alternatives for targeted cancer treatment. The present study evaluates the preparation of manganese ferrite magnetic nanoparticles (MnFe₂O₄ MNPs) encapsulated within Paclitaxel (PTX) loaded thioether-containing ω-hydroxyacid-co-poly(d,l-lactic acid) (TEHA-co-PDLLA) polymeric nanoparticles, for the combined hyperthermia and chemotherapy treatment of cancer. Initially, TEHA-co-PDLLA semitelechelic block copolymers were synthesized and characterized by ¹H-NMR, FTIR, DSC, and XRD. FTIR analysis showed the formation of an ester bond between the two compounds, while DSC and XRD analysis showed that the prepared copolymers were amorphous. MnFe₂O₄ MNPs of relatively small crystallite size (12 nm) and moderate saturation magnetization (64 emu·g⁻¹) were solvothermally synthesized in the sole presence of octadecylamine (ODA). PTX was amorphously dispersed within the polymeric matrix using emulsification/solvent evaporation method. Scanning electron microscopy along with energy-dispersive X-ray spectroscopy and transmission electron microscopy showed that the MnFe₂O₄ nanoparticles were effectively encapsulated within the drug-loaded polymeric nanoparticles. Dynamic light scattering measurements showed that the prepared nanoparticles had an average particle size of less than 160 nm with satisfactory yield and encapsulation efficiency. Diphasic PTX in vitro release over 18 days was observed while PTX dissolution rate was mainly controlled by the TEHA content. Finally, hyperthermia measurements and cytotoxicity studies were performed to evaluate the magnetic response, as well as the anticancer activity and the biocompatibility of the prepared nanocarriers.

Combinatorial effects of radiofrequency hyperthermia and radiotherapy in the presence of magneto-plasmonic nanoparticles on MCF-7 breast cancer cells

Here, the effects of combinatorial cancer therapy including radiotherapy (RT) and radiofrequency (RF) hyperthermia in the presence of gold-coated iron oxide nanoparticles (Au@IONPs), as a thermo-radio-sensitizer, are reported. The level of cell death and the ratio of Bax/Bcl2 genes, involved in the pathway of apoptosis, were measured to evaluate the synergistic effect of Au@IONPs-mediated RF hyperthermia and RT. MCF-7 human breast adenocarcinoma cells were treated with different concentrations of Au@IONPs. After incubation with NPs, the cells were exposed to RF waves (13.56 MHz; 100 W; 15 min). At the same time, thermometry was performed with an infrared (IR) camera. Then, the cells were exposed to 6 MV X-ray at various doses of 2 and 4 Gy. MTT (3-[4,5-dimethylthiazol-2-y1]-2,5-diphenyltetrazolium bromide) assay was performed to evaluate cell viability and quantitative real-time polymerase chain reaction (qRT-PCR) was used to determine the expression ratio of Bax/Bcl2. Cellular uptake of nanoparticles was confirmed qualitatively and quantitatively. The results obtained from MTT assay and qRT-PCR studies showed that NPs and RF hyperthermia had no significant effect when applied separately, while their combination had synergistic effects on cell viability percentage and the level of apoptosis induction. A synergistic effect was also observed when the cancer cells were treated with a combination of NPs, RF hyperthermia, and RT. On the basis of the obtained results, it may be concluded that the use of magneto-plasmonic NPs in the process of hyperthermia and RT of cancer holds a great promise to develop a new combinatorial cancer therapy strategy.

X-ray-activated nanosystems for theranostic applications

X-rays are widely applied in clinical medical facilities for radiotherapy (RT) and biomedical imaging. However, the sole use of X-rays for cancer treatment leads to insufficient radiation energy deposition due to the low X-ray attenuation coefficients of living tissues and organs, producing unavoidable excessive radiation doses with serious side effects to healthy body parts. Over the past decade, developments in materials science and nanotechnology have led to rapid progress in the field of X-ray-activated tumor-targeting nanosystems, which are able to tackle even systemic tumors and relieve the burden of exposure to large radiation doses. Additionally, novel imaging contrast agents and techniques have also been developed. In comparison with conventional external light sources (e.g., near infrared), the X-ray technique is ideal for the activation of nanosystems for cancer treatment and biomedical imaging applications due to its nearly unlimited penetration depth in living tissues and organisms. In this review, we systematically describe the interaction mechanisms between X-rays and nanosystems, and provide an overview of X-ray-sensitive materials and the recent progress on X-ray-activated nanosystems for cancer-associated theranostic applications.

The analysis of 2,3-dicarboxypropane-1,1-diphosphonic acid-coated magnetite nanoparticles under an external magnetic field and their radiolabeling for possible theranostic applications

The advances in nanotechnology are directed towards the development of new theranostic agents based on magnetic nanoparticles that can be used for both cancer detection and treatment.