Enhanced synergism of thermo-chemotherapy by combining highly efficient magnetic hyperthermia with magnetothermally-facilitated drug release

Nanoparticle-mediated thermal Cancer therapies: Strategies to improve clinical translatability

Despite significant advances, cancer remains a leading global cause of death. Current therapies often fail due to incomplete tumor removal and nonspecific targeting, spurring interest in alternative treatments. Hyperthermia, which uses elevated temperatures to kill cancer cells or boost their sensitivity to radio/chemotherapy, has emerged as a promising alternative. Recent advancements employ nanoparticles (NPs) as heat mediators for selective cancer cell destruction, minimizing damage to healthy tissues. This approach, known as NP hyperthermia, falls into two categories: photothermal therapies (PTT) and magnetothermal therapies (MTT). PTT utilizes NPs that convert light to heat, while MTT uses magnetic NPs activated by alternating magnetic fields (AMF), both achieving localized tumor damage. These methods offer advantages like precise targeting, minimal invasiveness, and reduced systemic toxicity. However, the efficacy of NP hyperthermia depends on many factors, in particular, the NP properties, the tumor microenvironment (TME), and TME-NP interactions. Optimizing this treatment requires accurate heat monitoring strategies, such as nanothermometry and biologically relevant screening models that can better mimic the physiological features of the tumor in the human body. This review explores the state-of-the-art in NP-mediated cancer hyperthermia, discussing available nanomaterials, their strengths and weaknesses, characterization methods, and future directions. Our particular focus lies in preclinical NP screening techniques, providing an updated perspective on their efficacy and relevance in the journey towards clinical trials.

Enhanced tumor penetration for efficient chemotherapy by a magnetothermally sensitive micelle combined with magnetic targeting and magnetic hyperthermia

The high accumulation and poor penetration of nanocarriers in tumor is a contradiction of nanomedicine, which reduces the efficacy of chemotherapy. Due to the positive effect of hyperthermia on in vivo drug diffusion, we designed a magnetothermally sensitive micelle (MTM) by integrating magnetic targeting (MT), magnetic hyperthermia (MH), and magnetothermally responsive drug release to facilitate simultaneous drug accumulation and penetration in tumor. Accordingly, we synthesized a cyanine7-modified thermosensitive polymer with phase transition at 42.3°C, and utilized it to prepare drug-loaded MTMs by encapsulating superparamagnetic MnFe2O4 nanoparticles and doxorubicin (DOX). The obtained DOX–MTM had not only high contents of DOX (9.1%) and MnFe2O4 (38.7%), but also some advantages such as superparamagnetism, high saturation magnetization, excellent magnetocaloric effect, and magnetothermal-dependent drug release. Therefore, DOX–MTM improved in vitro DOX cytotoxicity by enhancing DOX endocytosis under the assistance of MH. Furthermore, MT and MH enhanced in vivo DOX–MTM accumulation and DOX penetration in tumor, respectively, substantially inhibiting tumor growth (84%) with excellent biosafety. These results indicate the development of an optimized drug delivery system with MH and MH-dependent drug release, introducing a feasible strategy to enhance the application of nanomedicines in tumor chemotherapy.

Multifunctional Nanoparticles Based on Iron Oxide and Gold-198 Designed for Magnetic Hyperthermia and Radionuclide Therapy as a Potential Tool for Combined HER2-Positive Cancer Treatment

Iron oxide nanoparticles are commonly used in many medical applications as they can be easily modified, have a high surface-to-volume ratio, and are biocompatible and biodegradable. This study was performed to synthesize nanoparticles designed for multimodal HER2-positive cancer treatment involving radionuclide therapy and magnetic hyperthermia. The magnetic core (Fe₃O₄) was coated with a gold-198 layer creating so-called core-shell nanoparticles. These were then further modified with a bifunctional PEG linker and monoclonal antibody to achieve the targeted therapy. Monoclonal antibody—trastuzumab was used to target specific breast and nipple HER2-positive cancer cells. The nanoparticles measured by transmission electron microscopy were as small as 9 nm. The bioconjugation of trastuzumab was confirmed by two separate methods: thermogravimetric analysis and iodine-131 labeling. Synthesized nanoparticles showed that they are good heat mediators in an alternating magnetic field and exhibit great specific binding and internalization capabilities towards the SKOV-3 (HER2 positive) cancer cell line. Radioactive nanoparticles also exhibit capabilities regarding spheroid degradation without and with the application of magnetic hyperthermia with a greater impact in the case of the latter. Designed radiobioconjugate shows great promise and has great potential for in vivo studies regarding magnetic hyperthermia and radionuclide combined therapy.

Functionalized Magnetic Nanoparticles for Alternating Magnetic Field- or Near Infrared Light-Induced Cancer Therapies

The multi-faceted nature of functionalized magnetic nanoparticles (fMNPs) is well-suited for cancer therapy. These nanocomposites can also provide a multimodal platform for targeted cancer therapy due to their unique magnetic guidance characteristics. When induced by an alternating magnetic field (AMF), fMNPs can convert the magnetostatic energy to heat for magnetic hyperthermia (MHT), as well as for controlled drug release. Furthermore, with the ability to convert near-infrared (NIR) light energy to heat energy, fMNPs have attracted interest for photothermal therapy (PTT). Other than MHT and PTT, fMNPs also have a place in combination cancer therapies, such as chemo-MHT, chemo-PTT, and chemo-PTT-photodynamic therapy, among others, due to their versatile properties. Thus, this review presents multifunctional nanocomposites based on fMNPs for cancer therapies, induced by an AMF or NIR light. We will first discuss the different fMNPs induced with an AMF for cancer MHT and chemo-MHT. Secondly, we will discuss fMNPs irradiated with NIR lasers for cancer PTT and chemo-PTT. Finally, fMNPs used for dual-mode AMF + NIR-laser-induced magneto-photo-hyperthermia (MPHT) will be discussed.

Tailoring nanoparticles design for enhanced heating efficiency and improved magneto-chemo therapy for glioblastoma

Development of multifunctional magnetic nanomaterials (MNPs) with improved heat-generating capabilities and effective combination with localized chemotherapy has emerged as a promising therapeutic regime for solid tumors like glioblastoma. In this regard, the shape-dependent hyperthermic and chemo-therapeutic potential of nanomaterials, has not been extensively explored. Here we present, development of various morphological designs of MNPs including spherical, clusters, rods and cubic; to compare the effect of shape on tuning the properties of MNPs that are relevant to many potential biomedical applications like drug delivery, cellular uptake and heat generation. The study includes extensive comparison of morpho-structural characteristics, size distributions, chemical composition, surface area measurements and magnetic properties of the variable shaped MNPs. Further the heating efficiencies in aqueous and cellular environments and heat triggered drug release profiles for successful magneto-chemotherapy were compared among all in-house synthesized MNPs. Under biosafety limit considerations given by Hergt's limit (H*f value <5 × 10⁹ Am^-1 s^-1), cuboidal shaped MNPs demonstrated highest heating efficiency owing to magnetosome-like chain formation along with sustained drug release profile as compared to other synthesized MNPs. The mechanism of cancer cell death mediated via magneto-chemotherapy was elucidated to be the oxidative stress-mediated apoptotic cell death pathway. In vivo studies further demonstrated complete tumor regression only in the magneto-chemotherapy treated group. These findings suggest the potential of combinatorial therapy to overcome the clinical limitations of the independent therapies for advanced thermotherapy of glioblastoma.

TMZ magnetic temperature-sensitive liposomes-mediated magnetothermal chemotherapy induces pyroptosis in glioblastoma

Glioblastoma (GBM) is the most fatal and common type of primary malignant tumors in central nervous system. Chemotherapy drugs are difficult to reach the encephalic region effectively due to blood-brain barrier (BBB), but functional nanoparticle drug carriers can help to solve the problem. Herein, we developed a controllable drug carrier called temozolomide magnetic temperature-sensitive liposomes (TMZ/Fe-TSL) to investigate its feasibility and molecular mechanisms on GBM. Our research found TMZ/Fe-TSL exposed to alternating magnetic field (AMF) could induce significantly GBM cell death and promote the production of ROS. It also showed that the expression of NLRP3, CASP1 and N-GSDMD was upregulated compared to the control group, while the expression of CASP3 showed a reverse change. The results indicated that TMZ/Fe-TSL exposed to the AMF was capable of inducing GBM cells death. And the way and mechanisms of cell death may involve in ROS and pyroptosis, but not apoptosis.

Biomedical applications of metallic nanoparticles in cancer: Current status and future perspectives

The current advancements in nanotechnology are as an outcome of the development of engineered nanoparticles. Various metallic nanoparticles have been extensively explored for various biomedical applications. They attract lot of attention in biomedical field due to their significant inert nature, and nanoscale structures, with size similar to many biological molecules. Their intrinsic characteristics which include electronic, optical, physicochemical and, surface plasmon resonance, that can be changed by altering certain particle characteristics such as size, shape, environment, aspect ratio, ease of synthesis and functionalization properties have led to numerous applications in various fields of biomedicine. These include targeted drug delivery, sensing, photothermal and photodynamic therapy, imaging, as well as the modulation of two or three applications. The current article also discusses about the various properties of metallic nanoparticles and their applications in cancer imaging and therapeutics. The associated bottlenecks related to their clinical translation are also discussed.

A Theranostic Nanocomplex Combining with Magnetic Hyperthermia for Enhanced Accumulation and Efficacy of pH-Triggering Polymeric Cisplatin(IV) Prodrugs

Although polymeric platinum(IV) (Pt(IV)) prodrugs can reduce the side effects of cisplatin, the efficacy of the prodrug is still limited by its non-targeted distribution, poor penetration in deep tumor tissue, and low cytotoxicity in tumor cells. To improve the clinical potential of polymeric prodrug micelle, we synthesized amphiphilic polymeric Pt(IV) with high Pt content (22.5%), then developed a theranostic nanocomplex by integrating polymeric Pt(IV) with superparamagnetic Mn_0.6Zn_0.4Fe₂O₄ via simple self-assembly. Due to the high content of Mn_0.6Zn_0.4Fe₂O₄ (41.7% w/w), the theranostic nanocomplex showed high saturation magnetization (103.1 emu g⁻¹) and excellent magnetocaloric effect (404 W g⁻¹), both of them indicating its advantages in efficient magnetic targeting (MT), magnetic hyperthermia (MH), and magnetic resonance imaging (MRI). In vitro, in combination with MH, the theranostic nanocomplex showed as high cytotoxicity as cisplatin because of a significant increase in platinum of cellular uptake. In vivo, the accumulation of theranostic nanocomplex in tumors was increased by MT and confirmed by MRI. Furthermore, MH improved penetration of theranostic nanocomplex in tumors as expanding blackened area in tumors was observed by MRI. Based on these properties, the theranostic nanocomplex, under the assistance of MT and MH, showed the highest tumor growth inhibition rate (88.38%) after different treatments, while the body weight of mice increased slightly, indicating low side effects compared to those of cisplatin. The study provided an advanced theranostic nanocomplex with low toxicity and high efficacy, indicating a great clinical potential of polymeric Pt(IV).

Synthesis and Characterization of Magnetic Drug Carriers Modified with Tb3+ Ions

The study aimed to synthesize and characterize the magnetic drug carrier modified with terbium (III) ions. The addition of terbium extends the possibilities of their applications for targeted anticancer radiotherapy as well as for imaging techniques using radioisotopes emitting β⁺, β⁻, α, and γ radiation. The synthesis of iron oxide nanoparticles stabilized with citrates using the co-precipitation method (IONP @ CA) was carried out during the experimental work. The obtained nanoparticles were used to synthesize a conjugate containing terbium ions and guanosine-5′-monophosphate as an analog of drugs from the thiopurine group. Conjugates and their components were characterized using Transmission Electron Microscopy, infrared spectroscopy, X-ray microanalysis, spectrofluorimetry, and thermogravimetric analysis. The hybrid was also investigated with Langmuir layers to check the interaction with analogs of biological membranes.

Magnetic lipid nanovehicles synergize the controlled thermal release of chemotherapeutics with magnetic ablation while enabling non-invasive monitoring by MRI for melanoma theranostics

Nowadays, a number of promising strategies are being developed that aim at combining diagnostic and therapeutic capabilities into clinically effective formulations. Thus, the combination of a modified release provided by an organic encapsulation and the intrinsic physico-chemical properties from an inorganic counterpart opens new perspectives in biomedical applications. Herein, a biocompatible magnetic lipid nanocomposite vehicle was developed through an efficient, green and simple method to simultaneously incorporate magnetic nanoparticles and an anticancer drug (doxorubicin) into a natural nano-matrix. The theranostic performance of the final magnetic formulation was validated in vitro and in vivo, in melanoma tumors. The systemic administration of the proposed magnetic hybrid nanocomposite carrier enhanced anti-tumoral activity through a synergistic combination of magnetic hyperthermia effects and antimitotic therapy, together with MRI reporting capability. The application of an alternating magnetic field was found to play a dual role, (i) acting as an extra layer of control (remote, on-demand) over the chemotherapy release and (ii) inducing a local thermal ablation of tumor cells. This combination of chemotherapy with thermotherapy establishes a synergistic platform for the treatment of solid malignant tumors under lower drug dosing schemes, which may realize the dual goal of reduced systemic toxicity and enhanced anti-tumoral efficacy.

Hybrid Radiobioconjugated Superparamagnetic Iron Oxide-Based Nanoparticles for Multimodal Cancer Therapy

Superparamagnetic iron oxide nanoparticles (SPIONs) are widely used for biomedical applications for their outstanding properties such as facile functionalization and doping with different metals, high surface-to-volume ratio, superparamagnetism, and biocompatibility. This study was designed to synthesize and investigate multifunctional nanoparticle conjugate to act as both a magnetic agent, anticancer immunological drug, and radiopharmaceutic for anticancer therapy. The carrier, 166Ho doped iron oxide, was coated with an Au layer, creating core-shell nanoparticles ([166Ho] Fe3O4@Au. These nanoparticles were subsequently modified with monoclonal antibody trastuzumab (Tmab) to target HER2+ receptors. We describe the radiobioconjugate preparation involving doping of a radioactive agent and attachment of the organic linker and drug to the SPIONs' surface. The size of the SPIONs coated with an Au shell measured by transmission electron microscopy was about 15 nm. The bioconjugation of trastuzumab onto SPIONs was confirmed by thermogravimetric analysis, and the amount of two molecules per one nanoparticle was estimated with the use of radioiodinated [131I]Tmab. The synthesized bioconjugates showed that they are efficient heat mediators and also exhibit a cytotoxic effect toward SKOV-3 ovarian cancer cells expressing HER2 receptors. Prepared radiobioconjugates reveal the high potential for in vivo application of the proposed multimodal hybrid system, combined with magnetic hyperthermia and immunotherapy against cancer tissues.

Iron Oxide Nanoparticles Carrying 5-Fluorouracil in Combination with Magnetic Hyperthermia Induce Thrombogenic Collagen Fibers, Cellular Stress, and Immune Responses in Heterotopic Human Colon Cancer in Mice

In this study we looked for the main protein pathway regulators which were responsible for the therapeutic impact on colon cancers when combining magnetic hyperthermia with the chemotherapeutic agent 5-fluorouracil (5FU). To this end, chitosan-coated magnetic nanoparticles (MNP) functionalized with 5FU were intratumorally injected into subcutaneous human colon cancer xenografts (HT-29) in mice and exposed to an alternating magnetic field. A decreased tumor growth was found particularly for the combined thermo-chemotherapy vs. the corresponding monotherapies. By using computational analysis of the tumor proteome, we found upregulated functional pathway categories termed "cellular stress and injury", "intracellular second messenger and nuclear receptor signaling", "immune responses", and "growth proliferation and development". We predict TGF-beta, and other mediators, as important upstream regulators. In conclusion, our findings show that the combined thermo-chemotherapy induces thrombogenic collagen fibers which are able to impair tumor nutrient supply. Further on, we associate several responses to the recognition of damage associated molecular patterns (DAMPs) by phagocytic cells, which immigrate into the tumor area. The activation of some pathways associated with cell survival implies the necessity to conduct multiple therapy sessions in connection with a corresponding monitoring, which could possibly be performed on the base of the identified protein regulators.

Magnetic systems for cancer immunotherapy

Immunotherapy is a rapidly developing area of cancer treatment due to its higher specificity and potential for greater efficacy than traditional therapies. Immune cell modulation through the administration of drugs, proteins, and cells can enhance antitumoral responses through pathways that may be otherwise inhibited in the presence of immunosuppressive tumors. Magnetic systems offer several advantages for improving the performance of immunotherapies, including increased spatiotemporal control over transport, release, and dosing of immunomodulatory drugs within the body, resulting in reduced off-target effects and improved efficacy. Compared to alternative methods for stimulating drug release such as light and pH, magnetic systems enable several distinct methods for programming immune responses. First, we discuss how magnetic hyperthermia can stimulate immune cells and trigger thermoresponsive drug release. Second, we summarize how magnetically targeted delivery of drug carriers can increase the accumulation of drugs in target sites. Third, we review how biomaterials can undergo magnetically driven structural changes to enable remote release of encapsulated drugs. Fourth, we describe the use of magnetic particles for targeted interactions with cellular receptors for promoting antitumor activity. Finally, we discuss translational considerations of these systems, such as toxicity, clinical compatibility, and future opportunities for improving cancer treatment.

Synthesis, characterisation and functionalisation of BAB-type dual-responsive nanocarriers for targeted drug delivery: evolution of nanoparticles based on 2-vinylpyridine and diethyl vinylphosphonate

The emerging field of nanomedicine gives new opportunities in the treatment of cancer. Aspects such as dosage, bioavailability or the application to the patient can be drastically improved. Previously our group reported an efficient route towards cross-linked nanospheres based on ABB' block copolymers made from 2-vinylpyridine (2VP), diethyl vinylphosphonate (DEVP) and diallyl vinylphosphonate (DAlVP). Followed by thiol-ene click chemistry stable nanoparticles were formed. Herein, this promising concept was extended to copolymers with the analogous B'BABB' architecture. In this context the new yttrium complex 5 was investigated in the rare-earth metal-mediated group transfer polymerisation (REM-GTP) and used for the generation of copolymers with different monomer feeds (2VP: 100-300 equiv.; DEVP: 200-300 equiv.; DAlVP: 6-20 equiv.) to explore the influence of the copolymer compositon on the nanoparticle properties. After successful cross-linking with various cross-linking agents, all nanoparticles were characterised via DLS and TEM. These size measurements revealed defined, almost spherical particles (d DLS = 17-52 nm; d TEM = 17-43 nm) and were mainly affected by the 2VP content and the cross-linking density. Zeta potential measurements resulted in values in the range from -6 mV to -22 mV and revealed an influence of the cross-linking agent on the surface charge. Studies on the release behaviour exhibited the fastest release at pH = 4.5. Temperature-wise best results were achieved at 42 °C. Furthermore, we aimed for the conjugation of folic acid as a model compound for a potential application in active drug targeting. The consecutive couplings of cysteamine and dithiol 6 enabled the formation of an amine-modified precursor which was reacted with a folic acid derivative. Zeta potential measurements and analysis by NMR spectroscopy corroborated a successful conjugation while DLS and TEM (d DLS = 44 nm; d TEM = 38 nm) indicated defined nanoparticles.

Fabrication of thermoresponsive magnetic micelles from amphiphilic poly(phenyl isocyanide) and Fe3O4 nanoparticles for controlled drug release and synergistic thermochemotherapy

The drug-loaded micelles self-assembled from co-poly(phenyl isocyanide), Fe₃O₄ and DOX demonstrated thermoresponsiveness and magnetic hyperthermia for synergistic thermochemotherapy.

Molecular Stereocomplexation for Enhancing the Stability of Nanoparticles Encapsulated in Polymeric Micelles for Magnetic Resonance Imaging

A generalizable approach for improving the stability of polylactide-based (PLA-based) micelles for encapsulating nanoparticles (NPs) is demonstrated, using stereocomplexation between a pair of poly (ethylene glycol)-b-poly(d-lactide)/poly(ethylene glycol)-b-poly(l-lactide) block copolymer blends. Three different superparamagnetic ferrite-based NPs with distinct nanostructures are first prepared by the high-temperature pyrolysis method, including spherical MnFe₂O₄, cubic MnFe₂O₄, and core-shell MnFe₂O₄@Fe₃O₄. The diameters of these NPs are approximately 7-10 nm as revealed by transmission electron microscopy. These hydrophobic NPs can be encapsulated within self-assembled, stereocomplexed PLA (sc-PLA) micelles. All sc-PLA micelle systems loaded with three different NPs exhibit enhanced stability at elevated temperatures (20-60 °C) and with extended storage time (∼96 h) compared with analogous samples without stereocomplex formation, confirmed by dynamic light scattering measurements. The magnetic NP-loaded micelles with mean diameters of approximately 150 nm show both biocompatibility and superparamagnetic property. Under a 1.5 T magnetic field, cubic MnFe₂O₄ (c-MnFe₂O₄)-loaded micelles exhibit an excellent negative contrast enhancement of MR signals (373 mM^-1·s^-1), while core-shell MnFe₂O₄@Fe₃O₄-loaded micelles show a slightly lower signal for MR imaging (275 mM^-1·s^-1). These results suggest the potential of using sc-PLA-based polymer micelles as universal carriers for magnetic resonance imaging contrast agents with improved stability for different applications such as cancer diagnosis.

Magnetic nanoparticles for hyperthermia in cancer treatment: an emerging tool

Cancer remains as the major cause of death worldwide. The main reason why available therapies fail is that a vicious cycle in established which initiates multiple pathways and recurrence after metastasis. Hyperthermic treatment, which involves heating tumor tissues to a moderate temperature of 40-43 °C, has emerged as an effective strategy for treating tumors. This method is highly efficient at destroying tumor cells and does not induce the side effects of conventional cancer treatments. On the other hand, hyperthermic treatment method can be co-administered with conventional treatments. Nanotechnology had created huge opportunities in almost all areas of research, including the field of hyperthermic treatment. The utilization of magnetic nanoparticles (MNPs) offers functionalities not possible using conventional magnetic materials. In this review, we detail recent developments and applications of MNPs for hyperthermic treatment and discuss future possibilities.

In vitro Ultrasonic Potentiation of 2-Phenylethynesulfonamide/Magnetic Fluid Hyperthermia Combination Treatments for Ovarian Cancer

Background

Magnetic Fluid Hyperthermia (MFH) is a promising adjuvant for chemotherapy, potentiating the action of anticancer agents. However, drug delivery to cancer cells must be optimized to improve the overall therapeutic effect of drug/MFH combination treatments.

Purpose

The aim of this work was to demonstrate the potentiation of 2-phenylethynesulfonamide (PES) at various combination treatments with MFH, using low-intensity ultrasound as an intracellular delivery enhancer.

Methods

The effect of ultrasound (US), MFH, and PES was first evaluated individually and then as combination treatments. Definity^® microbubbles and polyethylene glycol (PEG)-coated iron oxide nanoparticles were used to induce cell sonoporation and MFH, respectively. Assessment of cell membrane permeabilization was evaluated via fluorescence microscopy, iron uptake by cells was quantified by UV-Vis spectroscopy, and cell viability was determined using automatic cell counting.

Results

Notable reductions in cancer cell viability were observed when ultrasound was incorporated. For example, the treatment US+PES reduced cell viability by 37% compared to the non-toxic effect of the drug. Similarly, the treatment US+MFH using mild hyperthermia (41°C), reduced cell viability by an additional 18% when compared to the effect of MH alone. Significant improvements were observed for the combination of US+PES+MFH with cell viability reduced by an additional 26% compared to the PES+MFH group. The improved cytotoxicity was attributed to enhanced drug/nanoparticle intracellular delivery, with iron uptake values nearly twice those achieved without ultrasound. Various treatment schedules were examined, and all of them showed substantial cell death, indicating that the time elapsed between sonoporation and magnetic field exposure was not significant.

Conclusion

Superior cancer cell-killing patterns took place when ultrasound was incorporated thus demonstrating the in vitro ultrasonic potentiation of PES and mild MFH. This work demonstrated that ultrasound is a promising non-invasive enhancer of PES/MFH combination treatments, aiming to establish a sono-thermo-chemotherapy in the treatment of ovarian cancer.

Flower-like Mn-Doped Magnetic Nanoparticles Functionalized with αvβ3-Integrin-Ligand to Efficiently Induce Intracellular Heat after Alternating Magnetic Field Exposition, Triggering Glioma Cell Death

Despite the potential of magnetic nanoparticles (NPs) to mediate intracellular hyperthermia when exposed to an alternating magnetic field (AMF), several studies indicate that the intracellular heating capacity of magnetic NPs depends on factors such as cytoplasm viscosity, nanoparticle aggregation within subcellular compartments, and dipolar interactions. In this work, we report the design and synthesis of monodispersed flowerlike superparamagnetic manganese iron oxide NPs with maximized SAR (specific absorption rate) and evaluate their efficacy as intracellular heaters in the human tumor-derived glioblastoma cell line U87MG. Three main strategies to tune the particle anisotropy of the core and the surface to reach the maximum heating efficiency were adopted: (1) varying the crystalline anisotropy by inserting a low amount of Mn²⁺ in the inverse spinel structure, (2) varying the NP shape to add an additional anisotropy source while keeping the superparamagnetic behavior, and (3) maximizing NP-cell affinity through conjugation with a biological targeting molecule to reach the NP concentration required to increase the temperature within the cell. We investigate possible effects produced by these improved NPs under the AMF (f = 96 kHz, H = 47 kA/m) exposure in the glioblastoma cell line U87MG by monitoring the expression of hsp70 gene and reactive oxygen species (ROS) production, as both effects have been described to be induced by increasing the intracellular temperature. The induced cell responses include cellular membrane permeabilization and rupture with concomitant high ROS appearance and hsp70 expression, followed by cell death. The responses were largely limited to cells that contained the NPs exposed to the AMF. Our results indicate that the developed strategies to optimize particle anisotropy in this work are a promising guidance to improve the heating efficiency of magnetic NPs in the human glioma cell line.

Actively Targeted Magnetothermally Responsive Nanocarriers/Doxorubicin for Thermochemotherapy of Hepatoma

Nanodrug-delivery systems modified with targeting molecules allow antitumor drugs to localize to tumor sites efficiently. CD147 protein is expressed highly on hepatoma cells. Firstly, we synthesized magnetothermally responsive nanocarriers/doxorubicin (MTRN/DOX) which was composed of manganese zinc (Mn-Zn) ferrite magnetic nanoparticles, amphiphilic and thermosensitivity copolymer drug carriers together with DOX. Then CD147-MTRN/DOX was formed with MTRN/DOX and monoclonal antibody that specifically binds to CD147 protein. It could target hepatoma cells actively and improve the DOX concentration in the tumor sites. Subsequently, an external alternating magnetic field elevated the temperature of the thermomagnetic particles, resulting in structural changes in the thermosensitive copolymer drug carriers, thereby releasing DOX. Hence, CD147-MTRN/DOX could enhance the responsiveness of hepatoma cells to the pre-existing chemotherapy drugs owing to active targeting combined synergistically with thermotherapy and chemotherapy, which has more significant anticancer effects than MTRN/DOX.

Recent advances in magnetic fluid hyperthermia for cancer therapy

Recently, magnetic fluid hyperthermia using biocompatible magnetic nanoparticles as heat mediators for cancer therapy has been extensively investigated due to its high efficiency and limited side effects. However, the development of more efficient heat nanomediators that exhibit very high specific absorption rate (SAR) value is essential for clinical application to overcome the several restrictions previously encountered due to the large quantity of nanomaterial required for effective treatment. In this review, we focus on the current progress in the development of magnetic nanoparticles based hyperthermia therapy as well as combined therapy harnessing hyperthermia with heat-mediated drug delivery for cancer treatment. We also address the fundamental principles of magnetic hyperthermia, basics of magnetism including the effect of several parameters on heating capacity, synthetic methods and nanoparticle surface chemistry needed to design and develop an ideal magnetic nanoparticle heat mediator suitable for clinical translation in cancer therapy.

Synthesis of next generation dual-responsive cross-linked nanoparticles and their application to anti-cancer drug delivery

Rare earth metal-mediated group transfer polymerisation enables the synthesis of previously inaccessible block copolymers of 2-vinylpyridine, diethyl vinylphosphonate and the new diallyl vinylphosphonate monomer. This precision polymerisation and the selective cross-linking of allyl side groups via thiol-ene click chemistry leads to the formation of well-defined dual-responsive nanoparticles. We demonstrate that these next generation nanocarriers are pH- and temperature-responsive and are capable of efficiently delivering doxorubicin into the nucleus of cancer cells. High anti-cancer activity could be demonstrated via cytotoxicity tests on breast cancer (MCF-7) and cervical cancer (HeLa) cells. These results validate this modular synthesis route as an ideal platform for the development of sophisticated nanocarriers for future drug delivery applications.

Advances in Magnetic Nanoparticles for Biomedical Applications

Magnetic nanoparticles (NPs) are emerging as an important class of biomedical functional nanomaterials in areas such as hyperthermia, drug release, tissue engineering, theranostic, and lab-on-a-chip, due to their exclusive chemical and physical properties. Although some works can be found reviewing the main application of magnetic NPs in the area of biomedical engineering, recent and intense progress on magnetic nanoparticle research, from synthesis to surface functionalization strategies, demands for a work that includes, summarizes, and debates current directions and ongoing advancements in this research field. Thus, the present work addresses the structure, synthesis, properties, and the incorporation of magnetic NPs in nanocomposites, highlighting the most relevant effects of the synthesis on the magnetic and structural properties of the magnetic NPs and how these effects limit their utilization in the biomedical area. Furthermore, this review next focuses on the application of magnetic NPs on the biomedical field. Finally, a discussion of the main challenges and an outlook of the future developments in the use of magnetic NPs for advanced biomedical applications are critically provided.

Effective elimination of liver cancer stem-like cells by CD90 antibody targeted thermosensitive magnetoliposomes

AIM

To investigate the use of thermosensitive magnetoliposomes (TMs) loaded with magnetic iron oxide (Fe3O4) and the anti-cancer stem cell marker CD90 (CD90@TMs) to target and kill CD90+ liver cancer stem cells (LCSCs).

METHODS

The hepatocellular carcinoma cell line Huh7 was used to separate CD90+ LCSCs by magnetic-activated cell sorting. CD90@TMs was characterized and their ability to target CD90+ LCSCs was determined. Experiments were used to investigate whether CD90@TMs combined with magnetic hyperthermia could effectively eliminate CD90+ LCSCs.

RESULTS

The present study demonstrated that CD90+ LCSCs with stem cells properties were successfully isolated. We also successfully prepared CD90@TMs that was almost spherical and uniform with an average diameter of 130±4.6 nm and determined that magnetic iron oxide could be incorporated and retained a superparamagnetic response. CD90@TMs showed good targeting and increased inhibition of CD90+ LCSCs in vitro and in vivo compared to TMs.

CONCLUSIONS

CD90@TMs can be used for controlled and targeted delivery of anticancer drugs, which may offer a promising alternative for HCC therapy.

Inhibition of cancer cell migration with CuS@ mSiO2-PEG nanoparticles by repressing MMP-2/MMP-9 expression

The metastasis of cancer cells is a vital aspect of disease progression and therapy. Although a few nanoparticles (NPs) aimed at controlling metastasis in cancer therapy have been reported, the NPs are normally combined with drugs, yet the direct therapeutic effects of the NPs are not reported. To study the direct influence of NPs on cancer metastasis, the potential suppression capacity of CuS@mSiO₂-PEG NPs to tumor cell migration, a kind of typical photothermal NPs, was systemically evaluated in this study. Using CuS@mSiO₂-PEG NP stimulation and a transwell migration assay, we found that the migration of HeLa cells was significantly decreased. This phenomenon may be associated with two classical proteins in metastasis: matrix metalloproteinase 2 (MMP-2) and matrix metalloproteinase 9 (MMP-9). In addition, the mechanism may closely associate with non-receptor tyrosine kinase protein (SRC)/focal adhesion kinase (FAK) signaling pathway which varies in vivo and in vitro. To confirm the differences in the expression of SRC and FAK, related inhibitors were studied for additional comparison. Also, the results indicated that even though the migration inhibition was closely related to SRC and FAK signaling pathway, there may be another unknown regulation mechanism existing and its metastasis inhibition was significant. Confirmed by long-term survival curve study, CuS@mSiO₂-PEG NPs significantly reduced the metastasis of cancer cells and improved the survival rates of metastasis in a mouse model. Thus, we believe that the direct influence of NPs on cancer cell metastasis is a promising study topic.

Preparation, characterization, biotoxicity, and biodistribution of thermo-responsive magnetic complex micelles formed by Mn0.6Zn0.4Fe2O4 and a PCL/PEG analogue copolymer for controlled drug delivery

A thermo-responsive PCL/PEG analogue copolymer (PCL-[b-P(MEO₂MA-co-OEGMA)]₂) with a lower critical solution temperature (LCST) of 40.4 °C at an MEO₂MA/OEGMA molar ratio of 87 : 13 was designed and synthesized. The copolymer was subsequently labeled by coupling with fluorescein isothiocyanate (FITC). Thermo-responsive magnetic PCL-[b-P(MEO₂MA-co-OEGMA)]₂/Mn_0.6Zn_0.4Fe₂O₄ (MZF) complex micelles were prepared by a self-assembly method. Doxorubicin (DOX) was loaded into the magnetic complex micelles as a model drug, and the DOX-MZF-micelles showed well-controlled thermo-responsive release both at externally fixed temperatures and in the presence of an alternating magnetic field (AMF). Both the blank polymer micelles and the magnetic complex micelles exhibited excellent stability in normal saline and serum. Based on the detection of the FITC fluorescence signal, the micelles were found to be effectively labeled by FITC. Furthermore, the biological toxicity of micelles was studied in vitro and in vivo. In vitro toxicity studies to evaluate cell viability and cell toxicity were performed by employing WST-1 and LDH release assays using HL7702 cells, respectively. In vivo biotoxicity studies were conducted in ICR mice through a series of tests: general conditions, body weight shifts, serum biochemistry profiles, and organ coefficient tests. All the biological toxicity results obtained from the blank polymer micelles and the magnetic complex micelles indicated their good biocompatibility and nontoxicity. The in vivo biodistribution studies of the FITC-labeled magnetic complex micelles were performed in the ICR mice. The copolymer was cleared by the kidney and spleen, while the MZF nanoparticles were cleared by the liver in time, causing no adverse effects on organisms. The thermo-responsive magnetic complex micelles were shown to be an ideal nanocarrier for anticancer drug delivery in terms of controlled release, stability, biocompatibility and safety.

Multifunctional Nanocarpets for Cancer Theranostics: Remotely Controlled Graphene Nanoheaters for Thermo-Chemosensitisation and Magnetic Resonance Imaging

A new paradigm in cancer theranostics is enabled by safe multifunctional nanoplatform that can be applied for therapeutic functions together with imaging capabilities. Herein, we develop a multifunctional nanocomposite consisting of Graphene Oxide-Iron Oxide -Doxorubicin (GO-IO-DOX) as a theranostic cancer platform. The smart magnetic nanoplatform acts both as a hyperthermic agent that delivers heat when an alternating magnetic field is applied and a chemotherapeutic agent in a cancer environment by providing a pH-dependent drug release to administer a synergistic anticancer treatment with an enhanced T2 contrast for MRI. The novel GO-IO-DOX nanocomposites were tested in vitro and were observed to exhibit an enhanced tumoricidal effect through both hyperthermia and cancer cell-specific DOX release along with an excellent MRI performance, enabling a versatile theranostic platform for cancer. Moreover the localized antitumor effects of GO-IO-DOX increased substantially as a result of the drug sensitization through repeated application of hyperthermia.

Design and application of a smart nanodevice by combining cationic drug delivery and hyperthermia for cancer apoptosis

Schematic illustration of the synergistic anticancer mechanism exhibited by smart mesoporous silica nanoparticles by combining cationic doxorubicin delivery with hyperthermia.

Optimum nanoscale design in ferrite based nanoparticles for magnetic particle hyperthermia

The study demonstrates the multiplex enhancement of the magnetic hyperthermia response by nanoscale design and magnetism tuning without sparing the biocompatibility of iron-oxide.

Enzyme and Thermal Dual Responsive Amphiphilic Polymer Core-Shell Nanoparticle for Doxorubicin Delivery to Cancer Cells

Dual responsive polymer nanoscaffolds for administering anticancer drugs both at the tumor site and intracellular compartments are made for improving treatment in cancers. The present work reports the design and development of new thermo- and enzyme-responsive amphiphilic copolymer core-shell nanoparticles for doxorubicin delivery at extracellular and intracellular compartments, respectively. A hydrophobic acrylate monomer was tailor-made from 3-pentadecylphenol (PDP, a natural resource) and copolymerized with oligoethylene glycol acrylate (as a hydrophilic monomer) to make new classes of thermo and enzyme dual responsive polymeric amphiphiles. Both radical and reversible addition-fragmentation chain transfer (RAFT) methodologies were adapted for making the amphiphilic copolymers. These amphiphilic copolymers were self-assembled to produce spherical core-shell nanoparticles in water. Upon heating, the core-shell nanoparticles underwent segregation to produce larger sized aggregates above the lower critical solution temperature (LCST). The dual responsive polymer scaffold was found to be capable of loading water insoluble drug, such as doxorubicin (DOX), and fluorescent probe-like Nile Red. The drug release kinetics revealed that DOX was preserved in the core-shell assemblies at normal body temperature (below LCST, ≤ 37 °C). At closer to cancer tissue temperature (above LCST, ∼43 °C), the polymeric scaffold underwent burst release to deliver 90% of loaded drugs within 2 h. At the intracellular environment (pH 7.4, 37 °C) in the presence of esterase enzyme, the amphiphilic copolymer ruptured in a slow and controlled manner to release >95% of the drugs in 12 h. Thus, both burst release of cargo at the tumor microenvironment and control delivery at intracellular compartments were accomplished in a single polymer scaffold. Cytotoxicity assays of the nascent and DOX-loaded polymer were carried out in breast cancer (MCF-7) and cervical cancer (HeLa) cells. Among the two cell lines, the DOX-loaded polymers showed enhanced killing in breast cancer cells. Furthermore, the cellular uptake of the DOX was studied by confocal and fluorescence microscopes. The present investigation opens a new enzyme and thermal-responsive polymer scaffold approach for DOX delivery in cancer cells.

Magnetic nanoparticles and nanocomposites for remote controlled therapies

This review highlights the state-of-the-art in the application of magnetic nanoparticles (MNPs) and their composites for remote controlled therapies. Novel macro- to nano-scale systems that utilize remote controlled drug release due to actuation of MNPs by static or alternating magnetic fields and magnetic field guidance of MNPs for drug delivery applications are summarized. Recent advances in controlled energy release for thermal therapy and nanoscale energy therapy are addressed as well. Additionally, studies that utilize MNP-based thermal therapy in combination with other treatments such as chemotherapy or radiation to enhance the efficacy of the conventional treatment are discussed.

Magnetothermally responsive star-block copolymeric micelles for controlled drug delivery and enhanced thermo-chemotherapy

Magnetothermally responsive drug-loaded micelles were designed and prepared for cancer therapy. These specially designed micelles are composed of the thermo-responsive star-block copolymer poly(ε-caprolactone)-block-poly(2-(2-methoxyethoxy)ethyl methacrylate-co-oligo(ethylene glycol)methacrylate) and Mn, Zn doped ferrite magnetic nanoparticles (MZF-MNPs). The thermo-responses of 6sPCL-b-P(MEO2MA-co-OEGMA) copolymers were shown to be dependent on the MEO2MA to OEGMA ratio. The lower critical solution temperature (LCST) of the star-block copolymers was controlled at 43 °C by adjusting the feed molar ratios of MEO2MA/OEGMA at 92 : 8. With the anti-tumor drug doxorubicin (DOX) self-assembling into the carrier system, the thermo-responsive micelles exhibited excellent temperature-triggered drug release behavior. In vitro cytotoxicity results showed high biocompatibility of the polymer micelles. Efficient cellular proliferation inhibition by the drug-loaded micelles was found on the HepG2 cells under different treatments. The thermo-responsive polymer micelles are promising for controlled drug delivery in tumor therapy under an alternating magnetic field.

Conjugated polymer and drug co-encapsulated nanoparticles for chemo- and photo-thermal combination therapy with two-photon regulated fast drug release

The spatial-temporal synchronization of photothermal therapy and chemotherapy is highly desirable for an efficient cancer treatment with synergistic effect. Herein, we developed a chemotherapeutic drug doxorubicin (DOX) and photothermal conjugated polymer (CP) co-loaded nanoplatform using a near-infrared (NIR) laser responsive amphiphilic brush copolymer as the encapsulation matrix. The obtained nanoparticles (NPs) exhibit good monodispersity and excellent stability, which can efficiently convert laser energy into thermal energy for photothermal therapy. Moreover, the hydrophobic polymer matrix bearing a number of 2-diazo-1,2-naphthoquinones (DNQ) moieties could be transformed to a hydrophilic one upon NIR two-photon laser irradiation, which leads to fast drug release. Furthermore, the surface modification of the NPs with cyclic arginine-glycine-aspartic acid (cRGD) tripeptide significantly enhances the accumulation of the NPs within integrin αvβ3 overexpressed cancer cells. The half-maximal inhibitory concentration (IC50) of the combination therapy is 13.7 μg mL(-1), while the IC50 for chemotherapy and photothermal therapy alone is 147.8 μg mL(-1) and 36.2 μg mL(-1), respectively. The combination index (C.I.) is 0.48 (<1), which indicates the synergistic effect for chemotherapy and PTT. These findings provide an excellent NIR laser regulated nanoplatform for combined cancer treatment with synergistic effect due to the synchronous chemo- and photo-thermal therapy.

Enhanced magnetic fluid hyperthermia by micellar magnetic nanoclusters composed of Mn(x)Zn(1-x)Fe(2)O(4) nanoparticles for induced tumor cell apoptosis

Monodispersed MnxZn1-xFe2O4 magnetic nanoparticles of 8 nm are synthesized and encapsulated in amphiphilic block copolymer for development of the hydrophilic magnetic nanoclusters (MNCs). These MNCs exhibit superparamagnetic characteristics, high specific absorption rate (SAR), large saturation magnetization (Ms), excellent stability, and good biocompatibility. MnFe2O4 and Mn0.6Zn0.4Fe2O4 are selected as optimum compositions for the MNCs (MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC) and employed for magnetic fluid hyperthermia (MFH) in vitro. To ensure biosafety of MFH, the parameters of alternating magnetic field (AMF) and exposure time are optimized with low frequency, f, and strength of applied magnetic field, Happlied. Under optimized conditions, MFH of MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC result in cancer cell death rate up to 90% within 15 min. The pathway of cancer cell death is identified as apoptosis, which occurs in mild hyperthermia near 43 °C. Both MnFe2O4/MNC and Mn0.6Zn0.4Fe2O4/MNC show similar efficiencies on drug-sensitive and drug-resistant cancer cells. On the basis of these findings, those MnxZn1-xFe2O4 nanoclusters can serve as a promising candidate for effective targeting, diagnosis, and therapy of cancers. The multimodal cancer treatment is also possible as amphiphilic block copolymer can encapsulate, in a similar fashion, different nanoparticles, hydrophobic drugs, and other functional molecules.