Iron Nanoparticles for Low-Power Local Magnetic Hyperthermia in Combination with Immune Checkpoint Blockade for Systemic Antitumor Therapy

Magnetic hyperthermia (MHT) utilizing heat generated by magnetic nanoparticles under alternating magnetic field (AMF) is an effective local tumor ablation method but can hardly treat metastatic tumors. In this work, we discover that pure iron nanoparticles (FeNPs) with high magnetic saturation intensity after being modified by biocompatible polymers are stable in aqueous solution and could be employed as a supereffective MHT agent to generate sufficient heating under a low-power AFM. Effective MHT ablation of tumors is then achieved, using either locally injected FeNPs or intravenously injected FeNPs with the help of locally applied tumor-focused constant magnetic field to enhance the tumor accumulation of those nanoparticles. We further demonstrate that the combination of FeNP-based MHT with local injection of nanoadjuvant and systemic injection of anticytotoxic T-lymphocyte antigen-4 (anti-CTLA4) checkpoint blockade would result in systemic therapeutic responses to inhibit tumor metastasis. A robust immune memory effect to prevent tumor recurrence is also observed after the combined MHT-immunotherapy. This work not only highlights that FeNPs with appropriate surface modification could act as a supereffective MHT agent but also presents the great promises of combining MHT with immunotherapy to achieve long-lasting systemic therapeutic outcome after local treatment.

Combined Magnetic Hyperthermia and Immune Therapy for Primary and Metastatic Tumor Treatments

Cancer immunotherapy shows promising potential in future cancer treatment but unfortunately is clinically unsatisfactory due to the low therapeutic efficacy and the possible severe immunotoxicity. Here we show a combined magnetic hyperthermia therapy (MHT) and checkpoint blockade immunotherapy for both primary tumor ablation and mimetic metastatic tumor inhibition. Monodispersed, high-performance superparamagnetic CoFe₂O₄@MnFe₂O₄ nanoparticles were synthesized and used for effective MHT-induced thermal ablation of primary tumors. Simultaneously, numerous tumor-associated antigens were produced to promote the maturation and activation of dendritic cells (DCs) and cytotoxic T cells for effective immunotherapy of distant mimetic metastatic tumors in a tumor-bearing mice model. The combined MHT and checkpoint blockade immunotherapy demonstrate the great potentials in the fight against both primary and metastatic tumors.

Applications of Antimicrobial Photodynamic Therapy against Bacterial Biofilms

Antimicrobial photodynamic therapy and allied photodynamic antimicrobial chemotherapy have shown remarkable activity against bacterial pathogens in both planktonic and biofilm forms. There has been little or no resistance development against antimicrobial photodynamic therapy. Furthermore, recent developments in therapies that involve antimicrobial photodynamic therapy in combination with photothermal hyperthermia therapy, magnetic hyperthermia therapy, antibiotic chemotherapy and cold atmospheric pressure plasma therapy have shown additive and synergistic enhancement of its efficacy. This paper reviews applications of antimicrobial photodynamic therapy and non-invasive combination therapies often used with it, including sonodynamic therapy and nanozyme enhanced photodynamic therapy. The antimicrobial and antibiofilm mechanisms are discussed. This review proposes that these technologies have a great potential to overcome the bacterial resistance associated with bacterial biofilm formation.

Hyperthermia treatment advances for brain tumors

Hyperthermia therapy (HT) of cancer is a well-known treatment approach. With the advent of new technologies, HT approaches are now important for the treatment of brain tumors. We review current clinical applications of HT in neuro-oncology and ongoing preclinical research aiming to advance HT approaches to clinical practice. Laser interstitial thermal therapy (LITT) is currently the most widely utilized thermal ablation approach in clinical practice mainly for the treatment of recurrent or deep-seated tumors in the brain. Magnetic hyperthermia therapy (MHT), which relies on the use of magnetic nanoparticles (MNPs) and alternating magnetic fields (AMFs), is a new quite promising HT treatment approach for brain tumors. Initial MHT clinical studies in combination with fractionated radiation therapy (RT) in patients have been completed in Europe with encouraging results. Another combination treatment with HT that warrants further investigation is immunotherapy. HT approaches for brain tumors will continue to a play an important role in neuro-oncology.

Superparamagnetic Gold Nanoparticles Synthesized on Protein Particle Scaffolds for Cancer Theragnosis

Cancer theragnosis using a single multimodality agent is the next mainstay of modern cancer diagnosis, treatment, and management, but a clinically feasible agent with in vivo cancer targeting and theragnostic efficacy has not yet been developed. A new type of cancer theragnostic agent is reported, based on gold magnetism that is induced on a cancer-targeting protein particle carrier. Superparamagnetic gold-nanoparticle clusters (named SPAuNCs) are synthesized on a viral capsid particle that is engineered to present peptide ligands targeting a tumor cell receptor (TCR). The potent multimodality of the SPAuNCs is observed, which enables TCR-specific targeting, T₂ -weighted magnetic resonance imaging, and magnetic hyperthermia therapy of both subcutaneous and deep-tissue tumors in live mice under an alternating magnetic field. Furthermore, it is analytically elucidated how the magnetism of the SPAuNCs is sufficiently induced between localized and delocalized spins of Au atoms. In particular, the SPAuNCs show excellent biocompatibility without the problem of in vivo accumulation and holds promising potential as a clinically effective agent for cancer theragnosis.

Recent Progress in the Synergistic Combination of Nanoparticle-Mediated Hyperthermia and Immunotherapy for Treatment of Cancer

Immunotherapy has demonstrated great clinical success in certain cancers, driven primarily by immune checkpoint blockade and adoptive cell therapies. Immunotherapy can elicit strong, durable responses in some patients, but others do not respond, and to date immunotherapy has demonstrated success in only a limited number of cancers. To address this limitation, combinatorial approaches with chemo- and radiotherapy have been applied in the clinic. Extensive preclinical evidence suggests that hyperthermia therapy (HT) has considerable potential to augment immunotherapy with minimal toxicity. This progress report will provide a brief overview of immunotherapy and HT approaches and highlight recent progress in the application of nanoparticle (NP)-based HT in combination with immunotherapy. NPs allow for tumor-specific targeting of deep tissue tumors while potentially providing more even heating. NP-based HT increases tumor immunogenicity and tumor permeability, which improves immune cell infiltration and creates an environment more responsive to immunotherapy, particularly in solid tumors.

Combinational Gene Therapy toward Cancer with Nanoplatform: Strategies and Principles

Cancer remains a significant threat to human health. While numerous therapies have been developed to combat the disease, traditional treatments such as chemotherapy and radiotherapy are suboptimal and associated with significant side effects. Gene therapy is an emerging therapeutic approach that offers improved targeting and reduced side effects compared with traditional treatments. Using siRNA and other nucleic acid-based drugs in cancer treatment has generated significant interest among researchers. Nanocarriers, such as liposomes, can effectively deliver these agents to tumor sites. However, gene therapy alone is often insufficient to eradicate tumors, and there is a risk of recurrence. Therefore, combining gene therapy with other therapies using nanocarriers, such as phototherapy and magnetic hyperthermia therapy, can lead to synergistic therapeutic effects through different mechanisms. In this review, we summarize various ways in which gene therapy can be combined with other therapies and highlight the role of nanoplatforms in mediating these combined therapies, which would inspire novel design ideas toward combination therapies. Additionally, bottlenecks and barriers to gene therapy should be addressed in the near future to achieve better clinical efficacy.

Controlled intracellular aggregation of magnetic particles improves permeation and retention for magnetic hyperthermia promotion and immune activation

Rationale: Magnetic nanoparticles (MNPs) are the most used inorganic nanoparticles in clinics with therapeutic and imaging functions, but the inefficient magneto-thermal conversion efficiency, fast leakage, and uneven distribution impair their imaging sensitivity and therapeutic efficacy in tumors. Methods: Herein, we rationally designed a system containing pH-controllable charge-reversible MNPs (M20@DPA/HA) and negatively charged MMPs with different sizes (M5 and M20), which could induce intracellular aggregation. The dynamic hydrazone bonds with pH controllability were formed by the surface hydrazides on MNPs and aldehydes of hyaluronic acid (HA). Under the acidic pH, intracellular aggregation of the complex composed by M20@DPA/HA and M5 (M5&20), or M20@DPA/HA and M20 (M20&20) were investigated. In addition, the magnetic hyperthermia therapy (MHT) efficiency of tumor cells, tumor-associated macrophages polarization, giant cells formation and immune activation of tumor microenvironment were explored via a series of cell and animal model experiments. Results: Through physical and chemical characterization, the aggregation system (M20&20) exhibited a remarkable 20-fold increase in magnetothermal conversion efficiency compared to individual MNPs, together with enhanced penetration and retention inside the tumor tissues. In addition, it could promote immune activation, including repolarization of tumor-associated macrophages, as well as the formation of giant cells for T cell recruitment. As a result, the M20&20 aggregation system achieved a high degree of inhibition in 4T1 mouse mammary tumor model, with little tumor growth and metastasis after magnetic hyperthermia therapy. Conclusions: A controlled intracellular aggregation system was herein developed, which displayed an aggregation behavior under the acidic tumor microenvironment. The system significantly enhanced MHT effect on tumor cells as well as induced M1 polarization and multinucleated giant cells (MGC) formation of TAM for immune activation. This controlled aggregation system achieved barely tumor growth and metastasis, showing a promising strategy to improve MNPs based MHT on deteriorate cancers.

Self-Amplified Apoptosis Targeting Nanoplatform for Synergistic Magnetic-Thermal/Chemo Therapy In Vivo

The low efficiency homing of nanomaterials in tumors remains a major challenge in nanomedicine. Inspired by the apoptosis targeting properties of phosphatidylserine (PS), a self-amplified apoptosis targeting nanoplatform (MNPs-ZnDPA/β-Lap) is fabricated combining Zn_0.4 Co_0.6 Fe₂ O₄ @Zn_0.4 Mn_0.6 Fe₂ O₄ nanoparticles (MNPs) with an excellent magnetic hyperthermia effect, a chemotherapeutic drug of β-lapachone (β-Lap) with the promotion of cell apoptosis, and the good apoptosis targeting moiety of Zn(II)-bis(dipicolylamine) (bis-ZnDPA) for PS. In an apoptotic 4T1 xenograft model, MNPs-ZnDPA/β-Lap can first accumulate in tumors by the EPR effect. The released β-Lap triggers the apoptosis of cancer cells in the tumor and increases the apoptotic target, which results in amplifying their apoptosis targeting properties. This self-amplified apoptosis targeting efficiency of MNPs-ZnDPA/β-Lap almost inhibits the growth of tumors with the synergistic magnetic-thermal/chemo therapy, which can offer a significant promise for targeting cancer theranostics.

Amplifying cancer treatment: advances in tumor immunotherapy and nanoparticle-based hyperthermia

In the quest for cancer treatment modalities with greater effectiveness, the combination of tumor immunotherapy and nanoparticle-based hyperthermia has emerged as a promising frontier. The present article provides a comprehensive review of recent advances and cutting-edge research in this burgeoning field and examines how these two treatment strategies can be effectively integrated. Tumor immunotherapy, which harnesses the immune system to recognize and attack cancer cells, has shown considerable promise. Concurrently, nanoparticle-based hyperthermia, which utilizes nanotechnology to promote selective cell death by raising the temperature of tumor cells, has emerged as an innovative therapeutic approach. While both strategies have individually shown potential, combination of the two modalities may amplify anti-tumor responses, with improved outcomes and reduced side effects. Key studies illustrating the synergistic effects of these two approaches are highlighted, and current challenges and future prospects in the field are discussed. As we stand on the precipice of a new era in cancer treatment, this review underscores the importance of continued research and collaboration in bringing these innovative treatments from the bench to the bedside.

Coating of Magnetite Nanoparticles with Fucoidan to Enhance Magnetic Hyperthermia Efficiency

Magnetic nanoparticles (NP), such as magnetite, have been the subject of research for application in the biomedical field, especially in Magnetic Hyperthermia Therapy (MHT), a promising technique for cancer therapy. NP are often coated with different compounds such as natural or synthetic polymers to protect them from oxidation and enhance their colloidal electrostatic stability while maintaining their thermal efficiency. In this work, the synthesis and characterization of magnetite nanoparticles coated with fucoidan, a biopolymer with recognized biocompatibility and antitumoral activity, is reported. The potential application of NP in MHT was evaluated through the assessment of Specific Loss Power (SLP) under an electromagnetic field amplitude of 14.7 kA m⁻¹ and at 276 kHz. For fucoidan-coated NP, it was obtained SLP values of 100 and 156 W/g, corresponding to an Intrinsic Loss Power (ILP) of 1.7 and 2.6 nHm²kg⁻¹, respectively. These values are, in general, higher than the ones reported in the literature for non-coated magnetite NP or coated with other polymers. Furthermore, in vitro assays showed that fucoidan and fucoidan-coated NP are biocompatible. The particle size (between ca. 6 to 12 nm), heating efficiency, and biocompatibility of fucoidan-coated magnetite NP meet the required criteria for MHT application.

Injectable Hydrogels Including Magnetic Nanosheets for Multidisciplinary Treatment of Hepatocellular Carcinoma via Magnetic Hyperthermia

Relapse and unresectability have become the main obstacle for further improving hepatocellular carcinoma (HCC) treatment effect. Currently, single therapy for HCC in clinical practice is limited by postoperative recurrence, intraoperative blood loss and poor patient outcomes. Multidisciplinary therapy has been recognized as the key to improving the long-term survival rate for HCC. However, the clinical application of HCC synthetic therapy is restricted by single functional biomaterials. In this study, a magnetic nanocomposite hydrogel (CG-IM) with iron oxide nanoparticle-loaded mica nanosheets (Iron oxide nanoparticles@Mica, IM) is reported. This biocompatible magnetic hydrogel integrated high injectability, magnetocaloric property, mechanical robustness, wet adhesion, and hemostasis, leading to efficient HCC multidisciplinary therapies including postoperative tumor margin treatment and percutaneous locoregional ablation. After minimally invasive hepatectomy of HCC, the CG-IM hydrogel can facilely seal the bleeding hepatic margin, followed by magnetic hyperthermia ablation to effectively prevent recurrence. In addition, CG-IM hydrogel can inhibit unresectable HCC by magnetic hyperthermia through the percutaneous intervention under ultrasound guidance.

Recent Developments in Magnetic Hyperthermia Therapy (MHT) and Magnetic Particle Imaging (MPI) in the Brain Tumor Field: A Scoping Review and Meta-Analysis

Magnetic hyperthermia therapy (MHT) is a promising treatment modality for brain tumors using magnetic nanoparticles (MNPs) locally delivered to the tumor and activated with an external alternating magnetic field (AMF) to generate antitumor effects through localized heating. Magnetic particle imaging (MPI) is an emerging technology offering strong signal-to-noise for nanoparticle localization. A scoping review was performed by systematically querying Pubmed, Scopus, and Embase. In total, 251 articles were returned, 12 included. Articles were analyzed for nanoparticle type used, MHT parameters, and MPI applications. Preliminary results show that MHT is an exciting treatment modality with unique advantages over current heat-based therapies for brain cancer. Effective application relies on the further development of unique magnetic nanoparticle constructs and imaging modalities, such as MPI, that can enable real-time MNP imaging for improved therapeutic outcomes.

Design of a temperature-feedback controlled automated magnetic hyperthermia therapy device

Introduction

Magnetic hyperthermia therapy (MHT) is a minimally invasive adjuvant therapy capable of damaging tumors using magnetic nanoparticles exposed radiofrequency alternating magnetic fields. One of the challenges of MHT is thermal dose control and excessive heating in superficial tissues from off target eddy current heating.

Methods

We report the development of a control system to maintain target temperature during MHT with an automatic safety shutoff feature in adherence to FDA Design Control Guidance. A proportional-integral-derivative (PID) control algorithm was designed and implemented in NI LabVIEW^®. A standard reference material copper wire was used as the heat source to verify the controller performance in gel phantom experiments. Coupled electromagnetic thermal finite element analysis simulations were used to identify the initial controller gains.

Results

Results showed that the PID controller successfully achieved the target temperature control despite significant perturbations.

Discussion and Conclusion

Feasibility of PID control algorithm to improve efficacy and safety of MHT was demonstrated.

A Novel Port to Facilitate Magnetic Hyperthermia Therapy for Glioma

High-grade gliomas (HGG) are the most common primary brain malignancy and continue to be associated with a dismal prognosis (median survival rate of 15-18 months) with standard of care therapy. Magnetic hyperthermia therapy (MHT) is an emerging intervention that leverages the ferromagnetic properties of magnetic iron-oxide nanoparticles (MIONPs) to target cancer cells that are otherwise left behind after resection. We report a novel port device to facilitate localization, delivery, and temperature measurement of MIONPs within a target lesion for MHT therapy. We conducted an in-depth literature and intellectual property review to define specifications of the conceived port device. After setting the design parameters, a thorough collaboration with neurological surgeons guided the iterative modeling process. A prototype was developed using Fusion 360 (Autodesk, San Rafael, CA) and printed on a Form 3 printer (Formlabs, Medford, MA) in Durable resin. The prototype was then tested in a phantom skull printed on a Pro-Jet 660Pro 3D printer (3D Systems, Rock Hill, SC) and a brain model based on mechanical and electrochemical properties of native brain tissue. This phantom underwent MHT heating tests using an alternating magnetic field (AMF) sequence based on current MHT workflow. Successful localization, delivery, and temperature measurement were demonstrated. The purpose of this study was twofold: first, to create and validate the procedural framework for a novel device, providing the groundwork for an upcoming comprehensive animal trial and second, to elucidate a cooperative approach between engineers and clinicians that propels advancements in medical innovation.

Design of the distribution of iron oxide (Fe3O4) nano-particle drug in realistic cholangiocarcinoma model and the simulation of temperature increase during magnetic induction hyperthermia

The prognosis for Cholangiocarcinoma (CCA) is unfavorable, necessitating the development of new therapeutic approach such as magnetic hyperthermia therapy (MHT) which is induced by magnetic nano-particle (MNPs) drug to bridge the treatment gap. Given the deep location of CCA within the abdominal cavity and proximity to vital organs, accurately predict the individualized treatment effects and safety brought by the distribution of MNPs in tumor will be crucial for the advancement of MHT in CCA. The Mimics software was used in this study to conduct three-dimensional reconstruction of abdominal computed tomography (CT) and magnetic reso-nance imaging images from clinical patients, resulting in the generation of a realistic digital geometric model representing the human biliary tract and its adjacent structures. Subsequently, The COMSOL Multiphysics software was utilized for modeling CCA and calculating the heat transfer law resulting from the multi-regional distribution of MNPs in CCA. The temperature within the central region of irregular CCA measured approximately 46°C, and most areas within the tumor displayed temperatures surpassing 41°C. The temperature of the inner edge of CCA is only 39 ∼ 41℃, however, it can be ameliorated by adjusting the local drug concentration through simulation system. For CCA with diverse morphologies and anatomical locations, the multi-regional distribution patterns of intratumoral MNPs and a slight overlap of drug distribution areas synergistically enhance intratumoral temperature while ensuring treatment safety. The present study highlights the practicality and imperative of incorporating personalized intratumoral MNPs distribution strategy into clinical practice for MHT, which can be achieved through the development of an integrated simulation system which incorporates medical image data and numerical calculations.

Promote lipolysis in white adipocytes by magnetic hyperthermia therapy with Fe3O4microsphere-doped hydrogel

Obesity has become an ongoing global crisis, since it increases the risks of cardiovascular disease, type 2 diabetes, fatty liver, cognitive decline, and some cancers. Adipose tissue is closely associated with the disorder of lipid metabolism. Several efforts have been made toward the modulation of lipid accumulation, but have been hindered by poor efficiency of cellular uptake, low safety, and uncertain effective dosage. Herein, we design an Fe3O4microsphere-doped composite hydrogel (Fe3O4microspheres @chitosan/β-glycerophosphate/collagen), termed as Fe3O4@Gel, as the magnetocaloric agent for magnetic hyperthermia therapy (MHT), aiming to promote lipolysis in white adipocytes. The experimental results show that the obtained Fe3O4@Gel displays a series of advantages, such as fast sol-gel transition, high biocompatibility, and excellent magneto-thermal performance. MHT, which is realized by Fe3O4@Gel subjected to an alternating magnetic field, leads to reduced lipid accumulation, lower triglyceride content, and increased mitochondrial activity in white adipocytes. This work shows that Fe3O4@Gel-mediated MHT can effectively promote lipolysis in white adipocytesin vitro, which provides a potential approach to treat obesity and associated metabolic disorders.

Nanovesicles for Lipid Metabolism Reprogram-Enhanced Ferroptosis and Magnetotherapy of Refractory Tumors and Inhibiting Metastasis with Activated Innate Immunity

Castration-resistant prostate cancer (CRPC) is an intractable disease, but approaches for eradicating primary tumors and inhibiting metastasis are limited. Considering that lipid metabolism plays key roles in ferroptosis and tumor progression and treatment resistance, here we developed a biomimetic nanovesicle (FiFe@RBM) encapsulating fatty acid synthetase inhibitors and iron oxide nanoparticles for synergistic therapy of CRPC and inhibiting the metastasis. FiFe@RBM with superior magnetic properties efficiently delivered drugs into the CRPC cancer cells, where it can release Fe ions to efficiently induce reactive oxygen species and mitochondrial dysfunction and inhibit the AKT-mTOR pathway, which synergistically causes apoptosis and enhances ferroptosis by rewired lipid metabolism through increasing polyunsaturated fatty acids (PUFAs), PUFA-enriched phosphatidylcholine (PUFA-PC), PUFA-enriched phosphatidylethanolamine (PUFA-PE), etc. By intravenous injection, the high accumulation of FiFe@RBM in PC-3 tumors enabled precision T1/T2-weighted magnetic resonance imaging-guided effective eradication of human CRPC PC-3 tumors by synergistic magnetic hyperthermia therapy (MHT) and ferroptosis, which further inhibited liver metastasis by the activated and recruited high rates of natural killer cells in the nude mice model. This work presents an effective nanovesicle strategy for reprogramming lipid metabolism to enhance ferroptosis in synergy with MHT for effectively treating refractory cancers.

Cubic Mesocrystal Magnetic Iron Oxide Nanoparticle Formation by Oriented Aggregation of Cubes in Organic Media: A Rational Design to Enhance the Magnetic Hyperthermia Efficiency

Magnetic iron oxide mesocrystals have been reported to exhibit collective magnetic properties and consequently enhanced heating capabilities under alternating magnetic fields. However, there is no universal mechanism to fully explain the formation pathway that determines the particle diameter, crystal size, and shape of these mesocrystals and their evolution along with the reaction. In this work, we have analyzed the formation of cubic magnetic iron oxide mesocrystals by thermal decomposition in organic media. We have observed that a nonclassical pathway leads to mesocrystals via the attachment of crystallographically aligned primary cubic particles and grows through sintering with time to achieve a sizable single crystal. In this case, the solvent 1-octadecene and the surfactant agent biphenyl-4-carboxylic acid seem to be the key parameters to form cubic mesocrystals as intermediates of the reaction in the presence of oleic acid. Interestingly, the magnetic properties and hyperthermia efficiency of the aqueous suspensions strongly depend on the degree of aggregation of the cores forming the final particle. The highest saturation magnetization and specific absorption rate values were found for the less aggregated mesocrystals. Thus, these cubic magnetic iron oxide mesocrystals stand out as an excellent alternative for biomedical applications with their enhanced magnetic properties.

In Situ Fabrication of Electrospun Magnetic Film under Laparoscopic Guidance for Preventing Postoperative Recurrence of Hepatocellular Carcinoma

Despite laparoscopic-guided minimally invasive hepatectomy emerging as the primary approach for resecting hepatocellular carcinoma (HCC), there is still a significant gap in suitable biomaterials that seamlessly integrate with these techniques to achieve effective hemostasis and suppress residual tumors at the surgical margin. Electrospun films are increasingly used for wound closure, yet the employment of prefabricated electrospun films for hemostasis during minimally invasive HCC resection is hindered by prolonged operation times, complexity in implementation, limited visibility during surgery, and inadequate postoperative prevention of HCC recurrence. In this study, montmorillonite-iron oxide sheets are integrated into the polyvinylpyrrolidone (PVP) polymer framework, enhancing the resulting electrospun PVP/montmorillonite-iron oxide (MI) film (abbreviated as PMI) with robustness, hemostatic capability, and magnetocaloric properties. In contrast to the in vitro prefabricated electrospun films, the electrospun PMI film is designed to be formed in situ on liver wounds under laparoscopic guidance during hepatectomy. This design affords superior wound adaptability, facilitating meticulous wound closure and expeditious hemostasis, thereby simplifying the operative process and ultimately alleviating the workload of healthcare professionals. Moreover, when exposed to an alternating magnetic field, the film can efficiently ablate residual tumors, significantly augmenting the treatment efficacy of HCC.

Injectable Magnetic Hydrogel Filler for Synergistic Bone Tumor Hyperthermia Chemotherapy

The therapeutic efficacy of bone tumor treatment is primarily limited by inadequate tumor resection, resulting in recurrence and metastasis, as well as the deep location of tumors. Herein, an injectable doxorubicin (DOX)-loaded magnetic alginate hydrogel (DOX@MAH) was developed to evaluate the efficacy of an alternating magnetic field (AMF)-responsive, chemothermal synergistic therapy for multimodality treatment of bone tumors. The prepared hydrogel exhibits a superior drug-loading capacity and a continuous DOX release. This multifunctionality can be attributed to the combined use of DOX for chemotherapy and iron oxide nanoparticle-containing alginate hydrogels as magnetic hyperthermia agents to generate hyperthermia for tumor elimination without the limit on penetration depth. Moreover, the hydrogel can be formed when in contact with the calcium ions, which are abundant in bone tissues; therefore, this hydrogel could perfectly fit the bone defects caused by the surgical removal of the bone tumor tissue, and the hydrogel could tightly attach the surgical margin of the bone to realize a high efficacy residual tumor tissue elimination treated by chemothermal synergistic therapy. The hydrogel demonstrates excellent hyperthermia performance, as evidenced by in vitro cytotoxicity tests on tumor cells. These tests reveal that the combined therapy based on DOX@MAH under AMF significantly induces cell death compared to single magnetic hyperthermia or chemotherapy. In vivo antitumor effects in tumor-bearing mice demonstrate that DOX@MAH injection at the tumor site effectively inhibits tumor growth and leads to tumor necrosis. This work not only establishes an effective DOX@MAH system as a synergistic chemothermal therapy platform for treating bone tumors but also sheds light on the application of alginate to combine calcium ions of the bone to treat bone defect diseases.