Biophysical mechanisms underlying the effects of static magnetic fields on biological systems

External stimuli-responsive drug delivery to the posterior segment of the eye

Posterior segment eye diseases represent the leading causes of vision impairment and blindness globally. Current therapies still have notable drawbacks, including the need for frequent invasive injections and the associated risks of severe ocular complications. Recently, the utility of external stimuli, such as light, ultrasound, magnetic field, and electric field, has been noted as a promising strategy to enhance drug delivery to the posterior segment of the eye. In this review, we briefly summarize the main physiological barriers against ocular drug delivery, focusing primarily on the recent advancements that utilize external stimuli to improve treatment outcomes for posterior segment eye diseases. The advantages of these external stimuli-responsive drug delivery strategies are discussed, with illustrative examples highlighting improved tissue penetration, enhanced control over drug release, and targeted drug delivery to ocular lesions through minimally invasive routes. Finally, we discuss the challenges and future perspectives in the translational research of external stimuli-responsive drug delivery platforms, aiming to bridge existing gaps toward clinical use.

Turbulence control in memristive neural network via adaptive magnetic flux based on DLS-ADMM technique

High-voltage defibrillation for eliminating cardiac spiral waves has significant side effects, necessitating the pursuit of low-energy alternatives for a long time. Adaptive optimization techniques and machine learning methods provide promising solutions for adaptive control of cardiac wave propagation. In this paper, the control of spiral waves and turbulence, as well as 2D and 3D heterogeneity in memristive neural network by using adaptive magnetic flux (AMF) is investigated based on dynamic learning of synchronization - alternating direction method of multipliers (DLS-ADMM). The results show that AMF can achieve global electrical synchronization under multiple complex conditions. There is a trade-off between AMF accuracy and computational speed, lowering the resolution of AMF requires a higher flux of magnetic fields to achieve the network synchronization, resulting in an increase in average Hamiltonian energy, which implies greater energy consumption. The AMF method is more energy efficient than existing DC and AC methods, but it relies on adequate resolution. The ADMM constraints can enhance the synchronization robustness and energy efficiency of DLS techniques, albeit at the cost of increased the computational complexity. The adaptive elimination of spiral waves and turbulence using AMF presented in this paper may provide a novel approach for the low-energy defibrillation studies, and its practical application and performance enhancement deserve further research.

Theoretical evaluation of the biological activity of hydrogen

Hydrogen (H2), the simplest and most ubiquitous molecule in the universe, has garnered significant scientific interest over the past two decades because of its potential as an effective antioxidant and anti-inflammatory agent. Traditionally considered inert, H2 is now being re-evaluated for its unique bioactive properties. H2 selectively neutralizes reactive oxygen and nitrogen species, mitigating oxidative stress without disrupting essential cellular functions. This review therefore aims to provide a theoretical evaluation of the biological activity of H2, focusing on its pharmacokinetics, including absorption, distribution, and retention within biological systems. The pharmacokinetic profile of H2 is crucial for understanding its potential therapeutic applications. The interaction of H2 with protein pockets is of particular interest, as these sites may serve as reservoirs or active sites for H2, influencing its biological activity and retention time. Additionally, the impact of H2 on cellular signaling pathways, including those regulating glucose metabolism and oxidative stress responses, will be explored, offering insights into its potential as a modulator of metabolic and redox homeostasis. Finally, interactions with ferromagnetic molecules within biological environments, as well as effects on cellular signaling mechanisms, add another layer of complexity to the biological role of H2. By synthesizing the current research, this review seeks to elucidate the underlying mechanisms by which H2 may exert therapeutic effects while also identifying critical areas for further investigation. Understanding these aspects is essential for fully characterizing the pharmacodynamic profile of H2 and assessing its clinical potential in the treatment of oxidative stress-related disorders.

The effects and mechanisms of electromagnetic fields on bone remodeling: From clinical to laboratory

Electromagnetic fields (EMFs) are physical fields generated by electrically charged objects, and play a vital role in the growth and development of living organisms. Bone is a highly dynamic structure that undergoes a constant remodeling process. From 1962 to 1977, Bassett discovered the piezoelectric effect in bone tissue and found that EMFs accelerated osteogenesis, promoted tibial fracture healing in dogs, and had positive effects in clinical trials. Since then, EMFs have been increasingly studied in bone remodeling disorders as a non-invasive physical therapy. This review summarizes clinical trials and laboratory studies on EMF interventions in bone remodeling disorders over the past few decades, outlining the effects of EMFs on various bone cells and their underlying molecular mechanisms. In addition, we propose issues in current studies and give an outlook on the research and application of EMFs as a non-invasive physical therapy.

The translational potential of this article

This article systematically reviews the research ranging from biological and physical mechanisms to medical applications of EMFs on bone remodeling and related diseases, identifies key challenges in future basic research, and proposes new strategies for developing novel medical equipment and advancing clinical applications in this field. These insights contribute to the advancement of non-invasive physical therapies in orthopedics.

Moderate static magnetic fields prevent estrogen deficiency-induced bone loss: Evidence from ovariectomized mouse model and small sample size randomized controlled clinical trial

BACKGROUND

Postmenopausal osteoporosis (PMOP) is the most common type of osteoporosis. Numerous studies have shown that static magnetic fields (SMFs) can inhibit bone loss by regulating bone remodeling. However, there are currently no clinical studies on the treatment of osteoporosis with SMFs. This study aims to investigate the clinical therapeutic effects of moderate static magnetic fields (MMFs) on PMOP.

METHODS

In this paper, we constructed MMF device using neodymium-iron-boron (NdFeB) materials. At the animal level, the effect of MMF exposure for 8 weeks on estrogen deficiency-induced bone loss was investigated by evaluating bone microstructure, mechanical properties, and bone conversion using ovariectomized (OVX) mice. Clinically, a single-blind randomized controlled study in patients with PMOP was designed. PMOP patients aged 55-70 years were recruited and randomized into the control and MMF treatment groups. Clinical assessments of bone mineral density (BMD), bone turnover markers (BTMs) and VAS scores were performed at baseline and day 90, respectively.

RESULTS

The results showed that MMF exposure significantly improved BMD, bone mineral content (BMC), bone microarchitecture and bone strength in OVX mice. For bone turnover, MMF increased the number of osteoblasts on the bone surface of OVX mice as well as the level of serum bone formation marker P1NP, while decreasing the number of osteoclasts and the level of serum bone resorption marker β-CTX. The clinical trial's results showed that MMF treatment had a positive effect on the improvement of BMD in the lumbar spine and increased serum P1NP levels while decreased β-CTX levels. In addition, MMF treatment decreased participants' VAS scores for low back pain.

CONCLUSIONS

The results of both animal and clinical studies demonstrated that MMF treatment improved bone turnover and have a positive effect on BMD improvement, as well as alleviated low back pain in PMOP patients. This study will promote the translational research and clinical application of SMF treatment for osteoporosis.

TRIAL REGISTRATION

Intervention study of moderate static magnetic field on osteoporosis and iron metabolism in postmenopausal women, ChiCTR2100048604.

Actin-Targeted Magnetic Nanomotors Mechanically Modulate the Tumor Mechanical Microenvironment for Cancer Treatment

The abnormal mechanical microenvironment is a hallmark feature of solid tumors and plays a key role in immunotherapy resistance. The actin cytoskeleton can be finely tuned to control cell mechanics, which becomes a central target to regulate the tumor mechanical microenvironment (TMME). Here, we propose an actin-binding protein-modified magnetic nanomotor (ABP-MN) coupled with the rotating magnetic field (MF) to dynamically regulate the actin cytoskeleton for remodeling the TMME. ABP-MNs, with an ultrasmall diameter of 23 nm, intracellularly target the actin cytoskeleton and induce depolymerization via magneto-mechanical force under MF. Cancer-associated fibroblasts (CAFs) and tumor cells, which internalize ∼69.3% of ABP-MNs, are significantly tuned under MF with signs of a 7-fold decrease in tumor matrix stiffness, increased immune cell infiltration, and 95.8% tumor growth inhibition. This strategy unlocks a fresh field to reshape the TMME with the intracellular mechanical approach, thereby providing an effective mechano-based therapy in treating solid tumors.

Magnetic activation of electrically active cells

Magnetic control of cell activity has applications ranging from non-invasive neurostimulation to remote activation of cell-based therapies. Unlike other methods of regulating cell activity like heat and light, which are based on known receptors or proteins, no magnetically gated channel has been identified to date. As a result, effective approaches for magnetic control of cell activity are based on strong alternating magnetic fields able to induce electric fields or materials that convert magnetic energy into electrical, thermal, or mechanical energy to stimulate cells. In our investigations of magnetic cell responses, we found that a spiking HEK cell line with no other co-factors responds to a magnetic field that reaches a maximum of 500 mT within 200 ms using a permanent magnet. The response is rare, approximately 1 in 50 cells, but is fast and reproducible, generating an action potential within 200 ms of magnetic field stimulation. The magnetic field stimulation is over 10,000 times slower than the magnetic fields used in transcranial magnetic stimulation (TMS) and the induced electric field is more than an order of magnitude lower than necessary for neuromodulation, suggesting that induced electric currents do not drive the cell response. Instead, our calculation suggests that this response depends on mechanoreception pathways activated by the magnetic torque of TRP-associated lipid rafts. Despite the relatively rare response to magnetic stimulation, when cells form gap junctions, the magnetic stimulation can propagate to nearby cells, causing tissue-level responses. As an example, we co-cultured spiking HEK cells with beta-pancreatic MIN6 cells and found that this co-culture responds to magnetic fields by increasing insulin production. Together, these results point toward a method for the magnetic control of biological activity without the need for a material co-factor such as synthetic nanoparticles. By better understanding this mechanism and enriching for magneto-sensitivity it may be possible to adapt this approach to the rapidly expanding tool kit for wireless cell activity regulation.

Carbon dioxide and weak magnetic field enhance iron-carbon micro-electrolysis combined autotrophic denitrification

Combining iron-carbon micro-electrolysis and autotrophic denitrification is promising for nitrate removal from wastewater. In this study, four continuous reactors were constructed using CO2 and weak magnetic field (WMF) to address challenges like iron passivation and pH stability. In the reactors with CO2 + WMF (10 and 35 mT), the increase in total nitrogen removal efficiency was significantly higher (96.2 ± 1.6 % and 94.1 ± 2.7 %, respectively) than that of the control (51.6 ± 2.7 %), and Fe3O4 converted to low-density FeO(OH) and FeCO3, preventing passivation film formation. The WMF application decreased the N2O emissions flux by 8.7 % and 20.5 %, respectively. With CO2 + WMF, the relative enzyme activity and abundance of denitrifying bacteria, especially unclassified_Rhodocyclaceae and Denitratisoma, increased. Thus, this study demonstrates that CO2 and WMF optimize the nitrate removal process, significantly enhancing removal efficiency, reducing greenhouse gas emissions, and improving process stability.

Effects of Short-, Medium-, and Long-Term Treatment Using Photobiomodulation Therapy Combined with Static Magnetic Field in Aging Rats

(1) Background: We investigated the detrimental and protective effects of short-, medium, and long-term treatment with different doses of photobiomodulation therapy combined with static magnetic field (PBMT-sMF) during the aging process. (2) Methods: Rats were treated for 15, 30, and 60 weeks with 1, 3, 10, and 30 J of PBMT-sMF or a placebo control. In addition, eight young rats were not subjected to any procedure or treatment and were euthanized at six weeks old. Skin, muscle, bone, kidney, liver, and blood samples were analyzed. (3) Results: No differences between the groups in the morphology of the skin, muscle, and bone was observed. Glutamic pyruvic transaminase levels were increased in the placebo group after 30 and 60 weeks. Glutamic oxaloacetic transaminase levels were also increased in the placebo group after 30 weeks. An increase in creatinine in the PBMT-sMF 3, 10, and 30 J groups compared with that in the young control group was observed. No significant difference in urea levels between the groups was noted. Vascular endothelial growth factor increased in the PBMT-sMF 10 and 30 J groups after 15 weeks of treatment and in the PBMT-sMF 3 J after 60 weeks. Finally, vascular endothelial growth factor decreased in the PBMT-sMF 30 J group after 30 weeks of treatment. (4) Conclusions: PBMT-sMF did not have detrimental effects on the skin, muscle, bone, kidney, or liver after short-, medium-, and long-term treatments in aging rats. In addition, PBMT-sMF may have protective effects on the muscle tissue in aging rats after short- and long-term treatment.

Static Magnetic Field Reduces the Anticancer Effect of Hinokitiol on Melanoma Malignant Cells-Gene Expression and Redox Homeostasis Studies

BACKGROUND

Melanoma malignant is characterized by a high mortality rate, accounting for as much as 65% of deaths caused by skin cancer. A potential strategy in cancer treatment may be the use of natural compounds, which include hinokitiol (β-Thujaplicin), a phenolic component of essential oils extracted from cypress trees. Many studies confirm that a high-induction SMF (static magnetic field) has anticancer effects and can be used as a non-invasive anticancer therapy in combination with or without drugs.

AIM

The aim of this experiment was to evaluate the effect of a static magnetic field on melanoma cell cultures (C32 and COLO 829) treated with hinokitiol.

METHODS AND RESULTS

Melanoma cells were exposed to a static magnetic field of moderate induction and hinokitiol. The research included determining the activity of the antioxidant enzymes (SOD, GPx, and CAT) and MDA concentration as well as the gene expression profile.

CONCLUSION

Hinokitiol disturbs the redox homeostasis of C32 and COLO 829 melanoma malignant cells. Moreover, a static magnetic field has a protective effect on melanoma malignant cells and abolishes the anticancer effect of hinokitiol.

Static magnetic fields in regenerative medicine

All organisms on Earth live in the weak but ubiquitous geomagnetic field. Human beings are also exposed to magnetic fields generated by multiple sources, ranging from permanent magnets to magnetic resonance imaging (MRI) in hospitals. It has been shown that different magnetic fields can generate various effects on different tissues and cells. Among them, stem cells appear to be one of the most sensitive cell types to magnetic fields, which are the fundamental units of regenerative therapies. In this review, we focus on the bioeffects of static magnetic fields (SMFs), which are related to regenerative medicine. Most reports in the literature focus on the influence of SMF on bone regeneration, wound healing, and stem cell production. Multiple aspects of the cellular events, including gene expression, cell signaling pathways, reactive oxygen species, inflammation, and cytoskeleton, have been shown to be affected by SMFs. Although no consensus yet, current evidence indicates that moderate and high SMFs could serve as a promising physical tool to promote bone regeneration, wound healing, neural differentiation, and dental regeneration. All in vivo studies of SMFs on bone regeneration and wound healing have shown beneficial effects, which unravel the great potential of SMFs in these aspects. More mechanistic studies, magnetic field parameter optimization, and clinical investigations on human bodies will be imperative for the successful clinical applications of SMFs in regenerative medicine.

Harmless and resourceful utilization of solid waste: Multi physical field regulation in the microbiological treatment process of solid waste treatment

Solid waste (SW) treatment methods mainly include physical, chemical, and biological methods, while physical and chemical methods have advantages such as fast effectiveness and short treatment time, but have high costs and were prone to secondary pollution. Due to the advantages of mild conditions and environmental protection, microbial methods have attracted the attention of numerous researchers. Recently, promotion of biological metabolic activity in biotreatment technology by applying multiple physical conditions, and reducing the biochemical reaction energy base to promote the transfer of protons and electrons, has made significant progress in harmless and resourceful utilization of SW. This paper main summarized the harmless and resourceful treatment methods of common bulk SW. The research of physical field-enhanced microbial treatment of inorganic solid waste (ISW) and organic solid waste (OSW) was discussed. The advantages and mechanisms of microbial treatment compared to traditional SW treatment methods were analyzed. The multi-physical field coupling enhanced microbial treatment technology was proposed to further improving the efficiency of large-scale treatment of bulk SW. The application prospects and potential opportunities of this technology were analyzed. Novel research ideas for the large-scale harmless and resourceful treatment of bulk SW were provided.

Coupling of static ultramicromagnetic field with elastic micropillar-structured substrate for cell response

Micropillars have emerged as promising tools for a wide range of biological applications, while the influence of magnetic fields on cell behavior regulation has been increasingly recognized. However, the combined effect of micropillars and magnetic fields on cell behaviors remains poorly understood. In this study, we investigated the responses of H9c2 cells to ultramicromagnetic micropillar arrays using NdFeB as the tuned magnetic particles. We conducted a comparative analysis between PDMS micropillars and NdFeB/PDMS micropillars to assess their impact on cell function. Our results revealed that H9c2 cells exhibited significantly enhanced proliferation and notable cytoskeletal rearrangements on the ultramicromagnetic micropillars, surpassing the effects observed with pure PDMS micropillars. Immunostaining further indicated that cells cultured on ultramicromagnetic micropillars displayed heightened contractility compared to those on PDMS micropillars. Remarkably, the ultramicromagnetic micropillars also demonstrated the ability to decrease reactive oxygen species (ROS) levels, thereby preventing F-actin degeneration. Consequently, this study introduces ultramicromagnetic micropillars as a novel tool for the regulation and detection of cell behaviors, thus paving the way for advanced investigations in tissue engineering, single-cell analysis, and the development of flexible sensors for cellular-level studies.

Moderate static magnetic field promotes fracture healing and regulates iron metabolism in mice

BACKGROUND

Fractures are the most common orthopedic diseases. It is known that static magnetic fields (SMFs) can contribute to the maintenance of bone health. However, the effect and mechanism of SMFs on fracture is still unclear. This study is aim to investigate the effect of moderate static magnetic fields (MMFs) on bone structure and metabolism during fracture healing.

METHODS

Eight-week-old male C57BL/6J mice were subjected to a unilateral open transverse tibial fracture, and following treatment under geomagnetic field (GMF) or MMF. The micro-computed tomography (Micro-CT) and three-point bending were employed to evaluate the microarchitecture and mechanical properties. Endochondral ossification and bone remodeling were evaluated by bone histomorphometric and serum biochemical assay. In addition, the atomic absorption spectroscopy and ELISA were utilized to examine the influence of MMF exposure on iron metabolism in mice.

RESULTS

MMF exposure increased bone mineral density (BMD), bone volume per tissue volume (BV/TV), mechanical properties, and proportion of mineralized bone matrix of the callus during fracture healing. MMF exposure reduced the proportion of cartilage in the callus area during fracture healing. Meanwhile, MMF exposure increased the number of osteoblasts in callus on the 14th day, and reduced the number of osteoclasts on the 28th day of fracture healing. Furthermore, MMF exposure increased PINP and OCN levels, and reduced the TRAP-5b and β-CTX levels in serum. It was also observed that MMF exposure reduced the iron content in the liver and callus, as well as serum ferritin levels while elevating the serum hepcidin concentration.

CONCLUSIONS

MMF exposure could accelerate fracture healing via promote the endochondral ossification and bone formation while regulating systemic iron metabolism during fracture healing. This study suggests that MMF may have the potential to become a form of physical therapy for fractures.

Magneto-mechanical stimulation modulates osteocyte fate via the ECM-integrin-CSK axis and wnt pathway

Osteocytes are the mechano-sensors of bones. Large gradient high-static magnetic fields (LG-HMFs) produce stable, high-precision, and non-attenuation mechanical forces. We discovered that magnetic forces opposite to gravity inhibited MLO-Y4 osteocyte proliferation and viability by inducing structural damage and apoptosis. In contrast, magnetic force loading in the same direction as that of gravity promoted the proliferation and inhibited apoptosis of MLO-Y4 osteocytes. Differentially expressed gene (DEG) analysis after magnetic force stimulation indicated that the ECM-integrin-CSK axis responded most significantly to mechanical signals. Wisp2 was the most significant DEG between the 12 T upward and downward groups, showing the highest correlation with the Wnt pathway according to the STRING protein interaction database. Explaining the cellular and molecular mechanisms by which mechanical stimuli influence bone remodeling is currently the focus of osteocyte-related research. Our findings provide insights into the effects of LG-HMFs on bone cells, which have further implications in clinical practice.