Biological effects of rotating magnetic field: A review from 1969 to 2021

Palliative effect of rotating magnetic field on glucocorticoid-induced osteonecrosis of the femoral head in rats by regulating osteoblast differentiation

With the substantial increase in the overuse of glucocorticoids (GCs) in clinical medicine, the prevalence of glucocorticoid-induced osteonecrosis of the femoral head (GC-ONFH) continues to rise in recent years. However, the optimal treatment for GC-ONFH remains elusive. Rotating magnetic field (RMF), considered as a non-invasive, safe and effective approach, has been proved to have multiple beneficial biological effects including improving bone diseases. To verify the effects of RMF on GC-ONFH, a lipopolysaccharide (LPS) and methylprednisolone (MPS)-induced invivo rat model, and an MPS-induced invitro cell model have been employed. The results demonstrate that RMF alleviated bone mineral loss and femoral head collapse in GC-ONFH rats. Meanwhile, RMF reduced serum lipid levels, attenuated cystic lesions, raised the expression of anti-apoptotic proteins and osteoprotegerin (OPG), while suppressed the expression of pro-apoptotic proteins and nuclear factor receptor activator-κB (RANK) in GC-ONFH rats. Besides, RMF also facilitated the generation of ALP, attenuated apoptosis and inhibits the expression of pro-apoptotic proteins, facilitated the expression of OPG, and inhibited the expression of RANK in MPS-stimulated MC3T3-E1 cells. Thus, this study indicates that RMF can improve GC-ONFH in rat and cell models, suggesting that RMF have the potential in the treatment of clinical GC-ONFH.

Electromagnetic fields effects on microbial growth in cocoa fermentation: A controlled experimental approach using established growth models

Understanding the effects of electromagnetic fields is crucial in the fermentation of cocoa beans, since through precise control of fermentation conditions the sensory and nutritional properties of cocoa beans could be improved. This study aimed to evaluate the effect of oscillating magnetic fields (OMF) on the kinetic growth of the core microbial communities of the Collections Castro Naranjal (CCN 51) cocoa bean. The data was obtained by three different models: Gompertz, Baranyi, and Logistic. The cocoa beans were subjected to different OMF strengths ranging from 0 mT to 80 mT for 1 h using the Helmholtz coil electromagnetic device. The viable microbial populations of lactic acid bacteria (LAB), acetic acid bacteria (AAB), and yeast (Y) were quantified using the colony-forming unit (CFU) counting method. The logistic model appropriately described the growth of LAB and Y under magnetic field exposure. Whereas the Baranyi model was suitable for describing AAB growth. The microbial populations in cocoa beans exposed to magnetic fields showed lower (maximum specific growth rate (μmax), values than untreated controls, with AAB exhibiting the highest average growth rate value at 5 mT and Y having the lowest average maximum growth rate value at 80 mT. The lower maximum specific growth rates and longer lag phases when exposed to magnetic fields compared to controls demonstrate the influence of magnetic fields on microbial growth kinetics.

Adhesion of Escherichia coli and Lactobacillus fermentum to Films and Electrospun Fibrous Scaffolds from Composites of Poly(3-hydroxybutyrate) with Magnetic Nanoparticles in a Low-Frequency Magnetic Field

The ability of materials to adhere bacteria on their surface is one of the most important aspects of their development and application in bioengineering. In this work, the effect of the properties of films and electrospun scaffolds made of composite materials based on biosynthetic poly(3-hydroxybutyrate) (PHB) with the addition of magnetite nanoparticles (MNP) and their complex with graphene oxide (MNP/GO) on the adhesion of E. coli and L. fermentum under the influence of a low-frequency magnetic field and without it was investigated. The physicochemical properties (crystallinity; surface hydrophilicity) of the materials were investigated by X-ray structural analysis, differential scanning calorimetry and "drop deposition" methods, and their surface topography was studied by scanning electron and atomic force microscopy. Crystal violet staining made it possible to reveal differences in the surface charge value and to study the adhesion of bacteria to it. It was shown that the differences in physicochemical properties of materials and the manifestation of magnetoactive properties of materials have a multidirectional effect on the adhesion of model microorganisms. Compared to pure PHB, the adhesion of E. coli to PHB-MNP/GO, and for L. fermentum to both composite materials, was higher. In the magnetic field, the adhesion of E. coli increased markedly compared to PHB-MNP/GO, whereas the effect on the adhesion of L. fermentum was reversed and was only evident in samples with PHB-MNP. Thus, the resultant factors enhancing and impairing the substrate binding of Gram-negative E. coli and Gram-positive L. fermentum turned out to be multidirectional, as they probably have different sensitivity to them. The results obtained will allow for the development of materials with externally controlled adhesion of bacteria to them for biotechnology and medicine.

Pulsed magnetic field increases the effect of ultraviolet C radiation and thermal shock in aged yeasts

The study of the effects of the magnetic field (MF) on living matter continues to be a dilemma. Until now, the interaction mechanisms of MF with living matter that explain the observed phenomena are unknown. Despite the existing literature and the multiple effects described to date, there are few published articles that study the combined effect of MF with other physical agents during the cellular aging process. In this sense, the aim of this work is to study whether low frequency and intensity pulsed and sinusoidal MF exposure produce alterations in the cell killing effect of ultraviolet C (UVC) radiation and thermal shock during the chronological aging of S. cerevisiae. Yeast cells were exposed to 2.45 mT (50 Hz) sinusoidal MF and 1.5 mT (25 Hz) pulsed MF, during 40 days of aging, in combination with UVC radiation (50 J/m2) and/or thermal shock (52°C). Cell survival was evaluated by clonogenic assay. The exposure of yeast to pulsed MF produces an acceleration of aging, which is not observed in cells exposed to sinusoidal MF. The pulsed MF modifies the cellular response to damaging agents only in aged S. cerevisiae cells. In this sense, the pulsed MF applied increases the damage induced by UVC radiation and by thermal shock. In contrast, the sinusoidal MF used has no effect.

Wireless Electrical Signals Induce Functional Neuronal Differentiation of BMSCs on 3D Graphene Framework Driven by Magnetic Field

Bone marrow mesenchymal stem cells (BMSCs) are suggested as candidates for neurodegeneration therapy by autologous stem cells to overcome the lack of neural stem cells in adults. However, the differentiation of BMSCs into functional neurons is a major challenge for neurotherapy. Herein, a methodology has been proposed to induce functional neuronal differentiation of BMSCs on a conductive three-dimensional graphene framework (GFs) combined with a rotating magnetic field. A wireless electrical signal of about 10 μA can be generated on the surface of GFs by cutting the magnetic field lines based on the well-known electromagnetic induction effect, which has been proven to be suitable for inducing neuronal differentiation of BMSCs. The enhanced expressions of the specific genes/proteins and apparent Ca2+ intracellular flow indicate that BMSCs cultured on GFs with 15 min/day rotating magnetic field stimulation for 15 days can differentiate functional neurons without any neural inducing factor. The animal experiments confirm the neural differentiation of BMSCs on GFs after transplantation in vivo, accompanied by stimulation of an external rotating magnetic field. This study overcomes the lack of autologous neural stem cells for adult neurodegeneration patients and provides a facile and safe strategy to induce the neural differentiation of BMSCs, which has potential for clinical applications of neural tissue engineering.

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.