The Anti-Depressive Effects of Ultra-High Static Magnetic Field.

BACKGROUND: Ultra-high field magnetic resonance imaging (MRI) has obvious advantages in acquiring high-resolution images. 7 T MRI has been clinically approved and 21.1 T MRI has also been tested on rodents. PURPOSE: To examine the effects of ultra-high field on mice behavior and neuron activity. STUDY TYPE: Prospective, animal model. ANIMAL MODEL: Ninety-eight healthy C57BL/6 mice and 18 depression model mice. FIELD STRENGTH: 11.1-33.0 T SMF (static magnetic field) for 1 hour and 7 T for 8 hours. Gradients were not on and no imaging sequence was used. ASSESSMENT: Open field test, elevated plus maze, three-chambered social test, Morris water maze, tail suspension test, sucrose preference test, blood routine, biochemistry examinations, enzyme-linked immunosorbent assay, immunofluorescent assay. STATISTICAL TESTS: The normality of the data was assessed by Shapiro-Wilk test, followed by Student's t test or the Mann-Whitney U test for statistical significance. The statistical cut-off line is P < 0.05. RESULTS: Compared to the sham group, healthy C57/6 mice spent more time in the center area (35.12 ± 4.034, increased by 47.19%) in open field test and improved novel index (0.6201 ± 0.02522, increased by 16.76%) in three-chambered social test a few weeks after 1 hour 11.1-33.0 T SMF exposure. 7 T SMF exposure for 8 hours alleviated the depression state of depression mice, including less immobile time in tail suspension test (58.32% reduction) and higher sucrose preference (increased by 8.80%). Brain tissue analysis shows that 11.1-33.0 T and 7 T SMFs can increase oxytocin by 164.65% and 36.03%, respectively. Moreover, the c-Fos level in hippocampus region was increased by 14.79%. DATA CONCLUSION: 11.1-33.0 T SMFs exposure for 1 hour or 7 T SMF exposure for 8 hours did not have detrimental effects on healthy or depressed mice. Instead, these ultra-high field SMFs have anti-depressive potentials. EVIDENCE LEVEL: 1 TECHNICAL EFFICACY: Stage 1.

Modulation of the Cell Membrane Potential and Intracellular Protein Transport by High Magnetic Fields.

To explore cellular responses to high magnetic fields (HMF), we present a model of the interactions of cells with a homogeneous HMF that accounts for the magnetic force exerted on paramagnetic/diamagnetic species. There are various chemical species inside a living cell, many of which may have large concentration gradients. Thus, when an HMF is applied to a cell, the concentration-gradient magnetic forces act on paramagnetic or diamagnetic species and can either assist or oppose large particle movement through the cytoplasm. We demonstrate possibilities for changing the machinery in living cells with HMFs and predict two new mechanisms for modulating cellular functions with HMFs via (i) changes in the membrane potential and (ii) magnetically assisted intracellular diffusiophoresis of large proteins. By deriving a generalized form for the Nernst equation, we find that an HMF can change the membrane potential of the cell and thus have a significant impact on the properties and biological functionality of cells. The elaborated model provides a universal framework encompassing current studies on controlling cell functions by high static magnetic fields. Bioelectromagnetics. 2021;42:27-36. © 2020 Bioelectromagnetics Society.

Cells in the Non-Uniform Magnetic World: How Cells Respond to High-Gradient Magnetic Fields.

Imagine cells that live in a high-gradient magnetic field (HGMF). Through what mechanisms do the cells sense a non-uniform magnetic field and how such a field changes the cell fate? We show that magnetic forces generated by HGMFs can be comparable to intracellular forces and therefore may be capable of altering the functionality of an individual cell and tissues in unprecedented ways. We identify the cellular effectors of such fields and propose novel routes in cell biology predicting new biological effects such as magnetic control of cell-to-cell communication and vesicle transport, magnetic control of intracellular ROS levels, magnetically induced differentiation of stem cells, magnetically assisted cell division, or prevention of cells from dividing. On the basis of experimental facts and theoretical modeling we reveal timescales of cellular responses to high-gradient magnetic fields and suggest an explicit dependence of the cell response time on the magnitude of the magnetic field gradient.

WITHDRAWN: Static High-Gradient Magnetic Fields Activate Transient Receptor Potential Vanilloid 4 (TRPV4) Ion Channels Enabling Remote Control of Cell Function.

This manuscript has been withdrawn by the Author's request.

Modulation of calcium signaling and metabolic pathways in endothelial cells with magnetic fields.

Calcium signaling plays a crucial role in various physiological processes, including muscle contraction, cell division, and neurotransmitter release. Dysregulation of calcium levels and signaling has been linked to a range of pathological conditions such as neurodegenerative disorders, cardiovascular disease, and cancer. Here, we propose a theoretical model that predicts the modulation of calcium ion channel activity and calcium signaling in the endothelium through the application of either a time-varying or static gradient magnetic field (MF). This modulation is achieved by exerting magnetic forces or torques on either biogenic or non-biogenic magnetic nanoparticles that are bound to endothelial cell membranes. Since calcium signaling in endothelial cells induces neuromodulation and influences blood flow control, treatment with a magnetic field shows promise for regulating neurovascular coupling and treating vascular dysfunctions associated with aging and neurodegenerative disorders. Furthermore, magnetic treatment can enable control over the decoding of Ca signals, ultimately impacting protein synthesis. The ability to modulate calcium wave frequencies using MFs and the MF-controlled decoding of Ca signaling present promising avenues for treating diseases characterized by calcium dysregulation.

Gradient Magnetic Field Accelerates Division of E. coli Nissle 1917.

Cell-cycle progression is regulated by numerous intricate endogenous mechanisms, among which intracellular forces and protein motors are central players. Although it seems unlikely that it is possible to speed up this molecular machinery by applying tiny external forces to the cell, we show that magnetic forcing of magnetosensitive bacteria reduces the duration of the mitotic phase. In such bacteria, the coupling of the cell cycle to the splitting of chains of biogenic magnetic nanoparticles (BMNs) provides a biological realization of such forcing. Using a static gradient magnetic field of a special spatial configuration, in probiotic bacteria E. coli Nissle 1917, we shortened the duration of the mitotic phase and thereby accelerated cell division. Thus, focused magnetic gradient forces exerted on the BMN chains allowed us to intervene in the processes of division and growth of bacteria. The proposed magnetic-based cell division regulation strategy can improve the efficiency of microbial cell factories and medical applications of magnetosensitive bacteria.

Interaction of magnetic fields with biogenic magnetic nanoparticles on cell membranes: Physiological consequences for organisms in health and disease.

The interaction mechanisms between magnetic fields (MFs) and living systems, which remained hidden for more than a hundred years, continue to attract the attention of researchers from various disciplines: physics, biology, medicine, and life sciences. Revealing these mechanisms at the cellular level would allow to understand complex cell systems and could help to explain and predict cell responses to MFs, intervene in organisms' reactions to MFs of different strengths, directions, and spatial distributions. We suggest several new physical mechanisms of the MF impacts on endothelial and cancer cells by the MF interaction with chains of biogenic and non-biogenic magnetic nanoparticles on cell membranes. The revealed mechanisms can play a hitherto unexpected role in creating physiological responses of organisms to externally applied MFs. We have also a set of theoretical models that can predict how cells will individually and collectively respond to a MF exposure. The physiological sequences of the MF - cell interactions for organisms in health and disease are discussed. The described effects and their underlying mechanisms are general and should take place in a large family of biological effects of MFs. The results are of great importance for further developing novel approaches in cell biology, cell therapy and medicine.

Intermittent F-actin Perturbations by Magnetic Fields Inhibit Breast Cancer Metastasis.

F-actin (filamentous actin) has been shown to be sensitive to mechanical stimuli and play critical roles in cell attachment, migration, and cancer metastasis, but there are very limited ways to perturb F-actin dynamics with low cell toxicity. Magnetic field is a noninvasive and reversible physical tool that can easily penetrate cells and human bodies. Here, we show that 0.1/0.4-T 4.2-Hz moderate-intensity low-frequency rotating magnetic field-induced electric field could directly decrease F-actin formation in vitro and in vivo, which results in decreased breast cancer cell migration, invasion, and attachment. Moreover, low-frequency rotating magnetic fields generated significantly different effects on F-actin in breast cancer vs. noncancerous cells, including F-actin number and their recovery after magnetic field retrieval. Using an intermittent treatment modality, low-frequency rotating magnetic fields could significantly reduce mouse breast cancer metastasis, prolong mouse survival by 31.5 to 46.0% (P < 0.0001), and improve their overall physical condition. Therefore, our work demonstrates that low-frequency rotating magnetic fields not only can be used as a research tool to perturb F-actin but also can inhibit breast cancer metastasis through F-actin modulation while having minimum effects on normal cells, which reveals their potential to be developed as temporal-controlled, noninvasive, and high-penetration physical treatments for metastatic cancer.

Effects of gradient high-field static magnetic fields on diabetic mice.

Although 9.4 T magnetic resonance imaging (MRI) has been tested in healthy volunteers, its safety in diabetic patients is unclear. Furthermore, the effects of high static magnetic fields (SMFs), especially gradient vs. uniform fields, have not been investigated in diabetics. Here, we investigated the consequences of exposure to 1.0-9.4 T high SMFs of different gradients (>10 T/m vs. 0-10 T/m) on type 1 diabetic (T1D) and type 2 diabetic (T2D) mice. We found that 14 h of prolonged treatment of gradient (as high as 55.5 T/m) high SMFs (1.0-8.6 T) had negative effects on T1D and T2D mice, including spleen, hepatic, and renal tissue impairment and elevated glycosylated serum protein, blood glucose, inflammation, and anxiety, while 9.4 T quasi-uniform SMFs at 0-10 T/m did not induce the same effects. In regular T1D mice (blood glucose ≥16.7 mmol/L), the >10 T/m gradient high SMFs increased malondialdehyde ( P<0.01) and decreased superoxide dismutase ( P<0.05). However, in the severe T1D mice (blood glucose ≥30.0 mmol/L), the >10 T/m gradient high SMFs significantly increased tissue damage and reduced survival rate. In vitro cellular studies showed that gradient high SMFs increased cellular reactive oxygen species and apoptosis and reduced MS-1 cell number and proliferation. Therefore, this study showed that prolonged exposure to high-field (1.0-8.6 T) >10 T/m gradient SMFs (35-1 380 times higher than that of current clinical MRI) can have negative effects on diabetic mice, especially mice with severe T1D, whereas 9.4 T high SMFs at 0-10 T/m did not produce the same effects, providing important information for the future development and clinical application of SMFs, especially high-field MRI.

Effects of High Magnetic Fields on the Diffusion of Biologically Active Molecules.

The diffusion of biologically active molecules is a ubiquitous process, controlling many mechanisms and the characteristic time scales for pivotal processes in living cells. Here, we show how a high static magnetic field (MF) affects the diffusion of paramagnetic and diamagnetic species including oxygen, hemoglobin, and drugs. We derive and solve the equation describing diffusion of such biologically active molecules in the presence of an MF as well as reveal the underlying mechanism of the MF's effect on diffusion. We found that a high MF accelerates diffusion of diamagnetic species while slowing the diffusion of paramagnetic molecules in cell cytoplasm. When applied to oxygen and hemoglobin diffusion in red blood cells, our results suggest that an MF may significantly alter the gas exchange in an erythrocyte and cause swelling. Our prediction that the diffusion rate and characteristic time can be controlled by an MF opens new avenues for experimental studies foreseeing numerous biomedical applications.

An upward 9.4 T static magnetic field inhibits DNA synthesis and increases ROS-P53 to suppress lung cancer growth.

Studies have shown that 9.4 Tesla (9.4 T) high-field magnetic resonance imaging (MRI) has obvious advantages in improving image resolution and capacity, but their safety issues need to be further validated before their clinical approval. Meanwhile, emerging experimental evidences show that moderate to high intensity Static Magnetic Fields (SMFs) have some anti-cancer effects. We examined the effects of two opposite SMF directions on lung cancer bearing mice and found when the lung cancer cell-bearing mice were treated with 9.4 T SMFs for 88 h in total, the upward 9.4 T SMF significantly inhibited A549 tumor growth (tumor growth inhibition=41%), but not the downward 9.4 T SMF. In vitro cellular analysis shows that 9.4 T upward SMF treatment for 24 h not only inhibited A549 DNA synthesis, but also significantly increased ROS and P53 levels, and arrested G2 cell cycle. Moreover, the 9.4 T SMF-treatments for 88 h had no severe impairment to the key organs or blood cell count of the mice. Our findings demonstrated the safety of 9.4 T SMF long-term exposure for their future applications in MRI, and revealed the anti-cancer potential of the upward direction 9.4 T SMF.

Magnetotunable left-handed FeSiB ferromagnetic microwires.

The magnetotunable left-handed characteristics of Fe(77.5)Si(12.5)B(10) glass-coated ferromagnetic microwires are analyzed in array and single microwire configuration, employing a rectangular waveguide working in X band. While the negative permeability is ascribed to the natural ferromagnetic resonance (NFMR) of the highly and positive magnetostrictive microwire, the negative permittivity features of the medium are attributed to the interaction of the microwires with the metallic rectangular waveguide. The dependence of the NFMR frequency on the applied external magnetic field enables the design of magnetotunable left-handed systems with wide-frequency band.

Model for hyperthermia with arrays of magnetic nanoparticles: spatial and time temperature distributions in tumor.

A square array of micron-sized needles containing magnetic nanoparticles has been studied theoretically as potential systems to deliver heat to tumor tissue for the hyperthermia treatment. The spatiotemporal distributions of temperature in a tumor were calculated for different arrays of microneedles. The resulting temperature distributions are found to be more uniform within the tumor target than those caused by other heating systems. Moreover, the temperature profiles could be tuned by a proper choice of the combination of the system parameters: the needle radius, the spatial needles period, as well as the filling fraction and parameters of magnetic nanoparticles.

Effect of static magnetic field on DNA synthesis: The interplay between DNA chirality and magnetic field left-right asymmetry.

Interactions between magnetic fields (MFs) and living cells may stimulate a large variety of cellular responses to a MF, while the underlying intracellular mechanisms still remain a great puzzle. On a fundamental level, the MF - cell interaction is affected by the two broken symmetries: (a) left-right (LR) asymmetry of the MF and (b) chirality of DNA molecules carrying electric charges and subjected to the Lorentz force when moving in a MF. Here we report on the chirality-driven effect of static magnetic fields (SMFs) on DNA synthesis. This newly discovered effect reveals how the interplay between two fundamental features of symmetry in living and inanimate nature-DNA chirality and the inherent features of MFs to distinguish the left and right-manifests itself in different DNA synthesis rates in the upward and downward SMFs, consequently resulting in unequal cell proliferation for the two directions of the field. The interplay between DNA chirality and MF LR asymmetry will provide fundamental knowledge for many MF-induced biological phenotypes.

Spatiotemporal magnetic fields enhance cytosolic Ca2+ levels and induce actin polymerization via activation of voltage-gated sodium channels in skeletal muscle cells.

Cellular function is modulated by the electric membrane potential controlling intracellular physiology and signal propagation from a motor neuron to a muscle fiber resulting in muscle contraction. Unlike electric fields, magnetic fields are not attenuated by biological materials and penetrate deep into the tissue. We used complex spatiotemporal magnetic fields (17-70 mT) to control intracellular signaling in skeletal muscle cells. By changing different parameters of the alternating magnetic field (amplitude, inversion time, rotation frequency), we induced transient depolarization of cellular membranes leading to i) Na+ influx through voltage-gated sodium channels (VGSC), ii) cytosolic calcium increase, and iii) VGSC- and ryanodine receptor-dependent increase of actin polymerization. The ion fluxes occurred only, when the field was applied and returned to baseline after the field was turned off. The 30-s-activation-cycle could be repeated without any loss of signal intensity. By contrast, static magnetic fields of the same strength exhibited no effect on myotube Ca2+ levels. Mathematical modeling suggested a role for the alternating magnetic field-induced eddy current, which mediates a local change in the membrane potential triggering the activation of VGSC. These findings might pave the way for the use of complex magnetic fields to improve function of skeletal muscles in myopathies.

Chemically different non-thermal plasmas target distinct cell death pathways.

A rigorous biochemical analysis of interactions between non-thermal plasmas (NTPs) and living cells has become an important research topic, due to recent developments in biomedical applications of non-thermal plasmas. Here, we decouple distinct cell death pathways targeted by chemically different NTPs. We show that helium NTP cells treatment, results in necrosome formation and necroptosis execution, whereas air NTP leads to mTOR activation and autophagy inhibition, that induces mTOR-related necrosis. On the contrary, ozone (abundant component of air NTP) treatment alone, exhibited the highest levels of reactive oxygen species production leading to CypD-related necrosis via the mitochondrial permeability transition. Our findings offer a novel insight into plasma-induced cellular responses, and reveal distinct cell death pathways triggered by NTPs.

How a High-Gradient Magnetic Field Could Affect Cell Life.

The biological effects of high-gradient magnetic fields (HGMFs) have steadily gained the increased attention of researchers from different disciplines, such as cell biology, cell therapy, targeted stem cell delivery and nanomedicine. We present a theoretical framework towards a fundamental understanding of the effects of HGMFs on intracellular processes, highlighting new directions for the study of living cell machinery: changing the probability of ion-channel on/off switching events by membrane magneto-mechanical stress, suppression of cell growth by magnetic pressure, magnetically induced cell division and cell reprograming, and forced migration of membrane receptor proteins. By deriving a generalized form for the Nernst equation, we find that a relatively small magnetic field (approximately 1 T) with a large gradient (up to 1 GT/m) can significantly change the membrane potential of the cell and thus have a significant impact on not only the properties and biological functionality of cells but also cell fate.

The interplay between biological and physical scenarios of bacterial death induced by non-thermal plasma.

Direct interactions of plasma matter with living cells and tissues can dramatically affect their functionality, initiating many important effects from cancer elimination to bacteria deactivation. However, the physical mechanisms and biochemical pathways underlying the effects of non-thermal plasma on bacteria and cell fate have still not been fully explored. Here, we report on the molecular mechanisms of non-thermal plasma-induced bacteria inactivation in both Gram-positive and Gram-negative strains. We demonstrate that depending on the exposure time plasma induces either direct physical destruction of bacteria or triggers programmed cell death (PCD) that exhibits characteristic features of apoptosis. The interplay between physical disruption and PCD is on the one hand driven by physical plasma parameters, and on the other hand by biological and physical properties of bacteria. The explored possibilities of the tuneable bacteria deactivation provide a basis for the development of advanced plasma-based therapies. To a great extent, our study opens new possibilities for controlled non-thermal plasma interactions with living systems.

Modulation of collective cell behaviour by geometrical constraints.

Intracellular and extracellular mechanical forces play a crucial role during tissue growth, modulating nuclear shape and function and resulting in complex collective cell behaviour. However, the mechanistic understanding of how the orientation, shape, symmetry and homogeneity of cells are affected by environmental geometry is still lacking. Here we investigate cooperative cell behaviour and patterns under geometric constraints created by topographically patterned substrates. We show how cells cooperatively adopt their geometry, shape, positioning of the nucleus and subsequent proliferation activity. Our findings indicate that geometric constraints induce significant squeezing of cells and nuclei, cytoskeleton reorganization, drastic condensation of chromatin resulting in a change in the cell proliferation rate and the anisotropic growth of cultures. Altogether, this work not only demonstrates complex non-trivial collective cellular responses to geometrical constraints but also provides a tentative explanation of the observed cell culture patterns grown on different topographically patterned substrates. These findings provide important fundamental knowledge, which could serve as a basis for better controlled tissue growth and cell-engineering applications.