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How to enhance the specific absorption rate of magnetic nanoparticles for hyperthermia?
Enhancement of specific absorption rate by exchange coupling of the core-shell structure of magnetic nanoparticles for magnetic hyperthermia. J Phys D Appl Phys. 2016:49
What is magnetic hyperthermia and how does it work?
Magnetic hyperthermia aims to produce the local heating by a magnetically-mediated heating of low-frequency electromagnetic waves, through the power absorption by magnetic nanoparticles. This technique is one of the most important approaches to induce the local heating by low electromagnetic radiation.
How to enhance hyperthermia efficiency of magnetotactic bacteria?
It was demonstrated that the biological structure of the magnetosome chain of magnetotactic bacteria is perfect to enhance the hyperthermia efficiency.
Does photomagnetic hyperthermia increase the temperature of a tumor?
The results showed that the temperature in the tumor increased by 22°C during photomagnetic hyperthermia treatment, which was consistent with the additive effect of the combined in vitrohyperthermia. Recently,Ma et al.
What is specific absorption rate in magnetic nanoparticles?
Despite their very low saturation magnetization (1.5–6.5 emu/g), the specific absorption rate (SAR) of the nanoparticles is 22–200 W/g at applied alternating magnetic field (AMF) with strengths of 100–500 Oe at a frequency of 160 kHz.
How does magnetic hyperthermia work?
Magnetic hyperthermia aims to produce the local heating by a magnetically-mediated heating of low-frequency electromagnetic waves, through the power absorption by magnetic nanoparticles. This technique is one of the most important approaches to induce the local heating by low electromagnetic radiation.
What is magnetic fluid hyperthermia?
Magnetic fluid hyperthermia involves the conversion of heat from magnetic nanoparticles via magnetic energy loss in the presence of an external AMF [18,19]. The produced heat is sufficient to kill the cancer cells and subsequently to destroy the tumor.
What temp is hyperthermia?
It's a life-threatening condition that causes your body temperature to rise above 104 degrees Fahrenheit. It causes problems in your brain and other organs.
What is MH treatment?
Immediate treatment of malignant hyperthermia includes: Medication. A drug called dantrolene (Dantrium, Revonto, Ryanodex) is used to treat the reaction by stopping the release of calcium into muscles.
How can hyperthermia be used for targeted drug delivery in the tumor?
Using temperature-sensitive liposomes (TSLs) is one way to achieve this; the liposome acts as a protective carrier, allowing increased drug to flow through the bloodstream by minimizing clearance and non-specific uptake. On reaching microvessels within a heated tumor, the drug is released and quickly penetrates.
How do nanoparticles work in hyperthermia?
Hyperthermia magnetic nanoparticles. Magnetic nanoparticles used as nano-heaters can be activated by an external magnetic field, through the magnetic coupling between the magnetic component of the field and their magnetic moment. Magnetic nanoparticles absorb the energy from this coupling phenomenon, and dissipate it as heat.
What is laser hyperthermia?
Laser hyperthermia. Heating of nanomaterials may also be activated by near-infrared (NIR) mediated by metallic nanoparticles (gold, silver, copper) or even semiconducting carbon nanotubes using laser hyperthermia. As well as magnetic hyperthermia, laser hyperthermia, requires an agent which interacts with light.
How does hyperthermia work?
Magnetic hyperthermia aims to produce the local heating by a magnetically-mediated heating of low-frequency electromagnetic waves, through the power absorption by magnetic nanoparticles. This technique is one of the most important approaches to induce the local heating by low electromagnetic radiation. Some of the challenges are the control of ...
Why are MNPs important?
Magnetic nanoparticles (MNPs) are remarkably interesting for biomedical applications due to their ability to respond to external magnetic fields which allow their remotely manipulation for targeting, cell separation, drug delivery, and of course also as nano-heaters to destroy tumours. The requirements to use MNPs for clinical purposes are their stability in biological environments and their low toxicity, in addition to their appropriate magnetic properties to be remotely activated by an external magnetic field.
What happens when you heat up a cell?
The exposure of mammalian cells to magnetic heating may induce cellular events that compromise and/or damage the cells, or may induce a controlled drug released. In cancer cells, as it is well known, high temperatures (42-45ºC) also induce necrosis or apoptosis.
What is the oldest therapy?
Magnetic Hyperthermia. Hyperthermia and photothermal therapy are some of the oldest therapies known, currently used as an anti-cancer therapy where the tumor temperature is increased to kill cancer cells and enhance the effectiveness of other therapies such as radiation or chemotherapy.
What radiation is used in laser hyperthermia?
The photothermic materials are excited with near-infrared (NIR) radiation which has a light range from 650 nm to 1024 nm.
What is MNPs MH?
Magnetic hyperthermia (MH) can be dated back to 1957, where Gilchrist et al. selectively heated the tumors by exploiting magnetic particles in the presence of an alternating magnetic field (AMF) [ 1 ]. With the rise in nanotechnology, the introduction of magnetic nanoparticles (MNPs) has further evolved this approach into a well-researched field [ 2 ]. The most significant advantage of MNPs-mediated MH (MNPs-MH) therapeutic modality is in the deep tissue penetration and magselectively killing of cancer cells without harming the surrounding healthy tissues [ 3 - 6 ]. MNPs-MH helps in realizing intracellular hyperthermia [ 7 ], as it directly delivers therapeutic heating to the cancer cells, and this intracellular hyperthermia can be further improved by conjugating the cell-targeting ligands with MNPs. The local and homogeneous heat leads to the greater selectivity and effectiveness of the treatment. Due to all these therapeutic benefits, MNPs-MH based tumor treatments have recently been translated from the lab to clinical trials, and they have been used for the treatment of glioblastoma and prostate cancer [ 8 ]. Many clinical trials were further performed by MagForce (Berlin, Germany), to investigate MNPs-MH therapy for pancreatic cancer. Although MNPs-MH therapy has been conducted in clinical trials, further research and development work are required to realise the full potential of this cancer nanotechnology. In particular, significant hurdles, such as the effectiveness and efficiency of MNPs-MH modality in cancer therapy have to be researched on, have to be overcome which posed challenges to this treatment modality.
How do MNPs-MH affect cancer?
MNPs-MH can lead to cancer cell death via the localized heat, which makes it an important cancer treatment modality. Gene therapy is another exciting research topic in current cancer treatment. Improving the efficacy can be achieved by controlling gene expression through genetic editing. Cellular systems have developed mechanisms to aid in adapting to thermal stress during evolution by inducing heat-shock proteins (HSPs) as the major target proteins [ 122 ]. Due to their high conservation across prokaryotes and eukaryotes, their importance in the cellular protection mechanisms is undeniable. By activating compensatory mechanisms by the heat-shock response, the cells are only then able to survive hyperthermia. It was shown that the mechanisms mediating heat-shock response are not strictly for protection towards heat, they also demonstrate protection towards other stress factors. The survivability of the cells under heat-shock is highly dependent on the conditions of the applied heat. This can lead to the therapeutic decision to use a desirable clinical setting in hyperthermia to trigger the cells into apoptotic/necrotic pathways. After heat-shock, the changes in gene expression (numerous genes are up- or down-regulated by heat-shock) are induced shortly and can last into the period of normothermia. HSPs are the major group of proteins expressed by this mechanism, which prevents the misaggregation of denatured protein after stress. In addition, HSPs also involved in the proper folding of nascent proteins into their required functional conformation. These proteins with functional conformation further regulate both the protein turnover and cellular redox-state. Members of the HSP40, HSP60, HSP70, and HSP90 families are some of the most well-known HSPs. The mechanism of their heat-responsive gene expression is of particular interest to the design of heat-responsive gene therapy vectors. Ito et al. proposed to enhance the heat stress gene to improve MH effect and to minimize the side effects [ 123 ]. Stem cell-based gene therapy shows tremendous potential for cancer treatment, but it is hard to control, which can lead to side effects. Yin et al. [ 124] reported magnetic core-shell nanoparticles to deliver and activate a heat-inducible gene vector that encodes tumor necrosis factor (TNF)-related apoptosis-inducing ligand (TRAIL) in adipose-derived mesenchymal stem cells (AD-MSCs). When the engineered AD-MSCS was generating heat under AMF exposure, TRAIL was selectively expressed, which induced significant ovarian cancer cell apoptosis and death in vitro and in vivo. Moreover, the engineered AD-MSCs still demonstrate their native ability to proliferate, differentiate, and target the tumors. MNPs-MH combined with gene therapy can complement their individual advantages to achieve a significant effect in cancer treatment. Wang et al. [ 125] reported a suicide gene as a promising alternative, which can convert a prodrug into a highly toxic drug. However, the drawback of this suicide gene is the difficulty in controlling its expression. MNPs is an excellent material for drug and gene delivery for various reasons: (1) it can be accumulated in the tumor cell, and then release the drug and gene to improve the effectiveness. (2) MNPs can generate heat under AMF exposure. Hence, magnetically targeted and hyperthermia-enhanced suicide gene therapy of hepatocellular carcinoma (HCC) was achieved.
What is MH in cancer?
Magnetic hyperthermia (MH) has been introduced clinically as an alternative approach for the focal treatment of tumors. MH utilizes the heat generated by the magnetic nanoparticles (MNPs) when subjected to an alternating magnetic field (AMF). It has become an important topic in the nanomedical field due to their multitudes of advantages towards effective antitumor therapy such as high biosafety, deep tissue penetration, and targeted selective tumor killing. However, in order for MH to progress and to realize its paramount potential as an alternative choice for cancer treatment, tremendous challenges have to be overcome. Thus, the efficiency of MH therapy needs enhancement. In its recent 60-year of history, the field of MH has focused primarily on heating using MNPs for therapeutic applications. Increasing the thermal conversion efficiency of MNPs is the fundamental strategy for improving therapeutic efficacy. Recently, emerging experimental evidence indicates that MNPs-MH produces nano-scale heat effects without macroscopic temperature rise. A deep understanding of the effect of this localized induction heat for the destruction of subcellular/cellular structures further supports the efficacy of MH in improving therapeutic therapy. In this review, the currently available strategies for improving the antitumor therapeutic efficacy of MNPs-MH will be discussed. Firstly, the recent advancements in engineering MNP size, composition, shape, and surface to significantly improve their energy dissipation rates will be explored. Secondly, the latest studies depicting the effect of local induction heat for selectively disrupting cells/intracellular structures will be examined. Thirdly, strategies to enhance the therapeutics by combining MH therapy with chemotherapy, radiotherapy, immunotherapy, photothermal/photodynamic therapy (PDT), and gene therapy will be reviewed. Lastly, the prospect and significant challenges in MH-based antitumor therapy will be discussed. This review is to provide a comprehensive understanding of MH for improving antitumor therapeutic efficacy, which would be of utmost benefit towards guiding the users and for the future development of MNPs-MH towards successful application in medicine.
Why are MNPs important?
As one of the most critical components in MNPs- MH, it is highly necessary for MNPs to be safe and highly efficient. MNPs are magnetic nanomediators that mediate the conversion of electromagnetic waves to thermal energy. As such, to improve the therapeutic efficacy of MNPs-MH, the most fundamental strategy is to increase the thermal conversion efficiency of MNPs. The inductive heating effect of MNPs, when subjected to an AMF, can be affected by numerous factors, such as hysteresis effect, relaxation effect, eddy current, domain wall, natural resonance, and so on [ 41 ]. When the strength and frequency of AMF are insufficient to cause significant eddy current, macroscopic thermal efficiency of MNPs should be closely related to their intrinsic physicochemical properties.
What is RT therapy?
Since the discovery of X-rays by Roentgen, radiation therapy (RT) has been portrayed as a standard treatment modality for cancer. However, the therapeutic effect is usually masked by its side effects faced by the normal tissue and the radiation resistance induced by hypoxia. MH plays a crucial role in the process of radiosensitization, which can enhance the damage to the tumor cells and blood vessels by interfering with the repair mechanism of tumor DNA after their injury. It has been demonstrated that the combination of MNPs-MH and RT not only can effectively kill resistant cells and lower toxicity to normal tissue, it can also lower the radiation dosage [ 103, 104 ]. Jiang et al. [ 105] designed a gadolinium-doped iron oxide nanoparticles (GdIONP) with higher SAR, and they explored its therapeutic effects when used in the combinatorial radio-thermotherapy. The results indicated that the efficacy of RT could be enhanced with GdIONP-mediated hyperthermia in two ways; (1) by reducing the fraction of hypoxic cells that contribute to radiation resistance and, (2) by inducing tumor-specific localized vascular disruption and necrosis. Due to the difficulty of external energy sources in reaching the targets to generate adequate heat, significant benefits of thermo-radiotherapy may be limited to superficial tumors [ 106 ]. Nevertheless, MH can also act as an adjuvant treatment to radiotherapy for metastatic breast cancer. Wang et al. [ 107] revealed a three synergistic actions by MH that resulted in a tremendous improvement in lung metastasis and in overall survival of mice under combinatorial MH/RT treatment; (1) promoting the anti-tumor efficiency of radiotherapy through Bax-mediated cell death, (2) improving cellular immunity which is suppressed under radiotherapy, and (3) decreasing the potential of radiotherapy to enhance MMP-9 expression.
What is the thermal effect of an AMF?
The thermal effect of the eddy current is in accordance with Joule's law. It has been commonly accepted that MNPs are capable of thermogenesis in the presence of AMF. Recently, it was reported that in addition to MNPs, other conductive non-magnetic materials also showed a thermogenic effect when exposed to an AMF. In 2016, Wang et al. [ 82] demonstrated that assembled films of Au NPs exhibited magnetothermal effect in the presence of an AMF, at a frequency of several hundreds of kHz. The mechanism lies in eddy-current heating, which roots in the alteration of the collective conductivity of the Au NPs. Lately, Gao et al. [ 83] was the first group to report the thermogenic effect of a clinically used hypertonic saline (HTS), which exhibited several physiological effects under AMF. This MH system has high safety and biodegradability, and can be used for comprehensive treatment after breast cancer surgery. The emergence of these non-magnetic materials with magnetic field responsiveness provides new research dimensions in the development of MH therapy for cancer treatment.
Can MIONs be used for chemotherapy?
MIONs not only can be utilized for targeted drug delivery and controlled drug release under an external field, but it can also be used as a trigger for magnetic field-mediated hyperthermia synergistic chemotherapy. Numerous studies have shown that MNPs-MH can induce vasodilation, i.e., the expansion of tumor blood vessels, which results in increased blood circulation and, therefore, effectively accelerating the intracellular drug delivery and release. Also, MNPs-MH provides a thermal enhancement that improves the drug cytotoxicity that is accompanied by interfering with the repair mechanism of tumor DNA and expression of multidrug resistance P-glycoprotein, thus damaging the way of tumor cells resisting apoptosis [ 92, 93 ].