Magnesium Ions Research Articles

Thermal stability of bivalent cation/phosphoinositide domains in model membranes

As key mediators in a wide array of signaling events, phosphoinositides (PIPs) orchestrate the recruitment of proteins to specific cellular locations at precise moments. This intricate spatiotemporal regulation of protein activity often necessitates the localized enrichment of the corresponding PIP. We investigate the extent and thermal stabilities of phosphatidylinositol-4-phosphate (PI(4)P), phosphatidylinositol-4,5-bisphosphate (PI(4,5)P2 and phosphatidylinositol-3,4,5-trisphosphate (PI(3,4,5)P3) clusters with calcium and magnesium ions. We observe negligible or minimal clustering of all examined PIPs in the presence of Mg2+ ions. While PI(4)P shows in the presence of Ca2+ no clustering, PI(4,5)P2 forms with Ca2+ strong clusters that exhibit stablity up to at least 80°C. The extent of cluster formation for the interaction of PI(3,4,5)P3 with Ca2+ is less than what was observed for PI(4,5)P2, yet we still observe some clustering up to 80°C. Given that cholesterol has been demonstrated to enhance PIP clustering, we examined whether bivalent cations and cholesterol synergistically promote PIP clustering. We found that the interaction of Mg2+ or Ca2+ with PI(4)P remains extraordinarily weak, even in the presence of cholesterol. In contrast, we observe synergistic interaction of cholesterol and Ca2+ with PI(4,5)P2. Also, in the presence of cholesterol, the interaction of Mg2+ with PI(4,5)P2 remains weak. PI(3,4,5)P3 does not show strong clustering with cholesterol for the experimental conditions of our study and the interaction with Ca2+ and Mg2+ was not influenced by the presence of cholesterol.

Magnesium Ion: A New Switch in Tumor Treatment.

The magnesium ion is an essential cation in the human body and participates in numerous physiological activities. A deficiency in magnesium ions is closely associated with tumor development, and supplementation with magnesium ions has been shown to partially inhibit tumor growth. However, the specific mechanisms by which magnesium ions suppress tumor proliferation remain unclear. Currently, studies have revealed that mitochondria may serve as a crucial intermediate link in the regulation of tumors by magnesium ions. Mitochondria might intervene in the proliferation and invasion of tumor cells by modulating energy metabolism and oxidative stress levels. Regrettably, there has been no comprehensive review of the role of magnesium in cancer therapy to date. Therefore, this article provides a comprehensive scrutiny of the relationship between magnesium ions and tumors, aiming to offer insights for clinical tumor treatment strategies involving magnesium ion intervention.

Migration of copper(II) ions in humic systems—effect of incorporated calcium(II), magnesium(II), and iron(III) ions

The mobility of heavy metals in natural soil systems can be affected by the properties and compositions of those systems: the content and quality of organic matter as well as the character of inorganic constituents. In this work, the diffusion of copper(II) ions in humic hydrogels with incorporated calcium(II), magnesium(II), and iron(III) ions was investigated. The methods of instantaneous planar source and of constant source were used. Experimental data yielded the time development of the concentration in hydrogels and the values of effective diffusion coefficients. The coefficients include both the influence of the hydrogel structure and the interaction of diffusing particles with the hydrogel. Our results showed that the presence of natural metal ions such as calcium, magnesium, or iron can strongly affect the diffusivity of copper in humic systems. They indicate that the mobility of copper ions depends on their concentration. The mobility can be supported by higher contents of copper in the system. While the incorporation of Ca and Mg resulted in the decrease in the diffusivity of copper ions, the incorporation of Fe(III) into humic hydrogel resulted in an increase in the diffusivity of Cu(II) in the hydrogel in comparison with pure humic hydrogel.

Improving mechanical strength and osteo-stimulative capacity of 3D-printed magnesium phosphate ceramic scaffolds by magnesium silicate additives

Magnesium phosphate ceramics are short of osteostimulation capacity to effectively repair the bone defects. Herein, magnesium silicate (MgSi) was utilized as an additive to modify the 3D-printed magnesium phosphate (MgP) ceramic scaffolds. The results presented that the addition of MgSi was conducive to enhancement of compressive strength of the MgP/MgSi ceramic composite scaffolds, and the scaffolds incorporating 20 wt% MgSi had the highest value. The degradation of MgP/MgSi scaffolds resulted in a decrease of mechanical strength and the continuous release of magnesium and silicon ions. In comparison with MgP scaffolds, the MgP/MgSi scaffolds promoted the growth and osteogenic gene expression of bone marrow mesenchymal stem cells. Collectively, the 3D-printed MgP/MgSi scaffolds with high mechanical strength and osteo-stimulation effects are potential biomaterials for the effective restoration of bone defects.

Effects of Calcium and Magnesium Ion Ratios in Natural and Drinking Water on the Vitality of Test Organisms

Effects of Calcium and Magnesium Ion Ratios in Natural and Drinking Water on the Vitality of Test Organisms

Study on the mechanism of different metal ions synergistic with alkali etching treatment in the flotation of lepidolite and feldspar

The two minerals were separated through alkali etching on the surface of lepidolite and feldspar, in conjunction with metal ion activation flotation. The activation of calcium (Ca2+) ion, magnesium (Mg2+) ion, copper (Cu2+) ion, and ferric (Fe3+) ion under alkali and non-alkali corrosion conditions was investigated, respectively. Micro-flotation experiments demonstrate that Ca2+ and Mg2+ can selectively recover lepidolite but not feldspar when the pH is above 6.5 during alkali etching. The activation of Cu2+ and Fe3+ flotation is not selective and can activate lepidolite and feldspar to some extent, irrespective of alkali etching. Through the valence bond theory, the selectivity of lepidolite and feldspar to dissolve and break bonds under alkali etching in a solution system was calculated. The adsorption differences and mechanisms of four types of metal ions were analyzed using solution chemistry, particle size analysis, and X-ray photoelectron spectroscopy (XPS) detections.

High-resolution yeast actin structures indicate the molecular mechanism of actin filament stiffening by cations

Actin filament assembly and the regulation of its mechanical properties are fundamental processes essential for eukaryotic cell function. Residue E167 in vertebrate actins forms an inter-subunit salt bridge with residue K61 of the adjacent subunit. Saccharomyces cerevisiae actin filaments are more flexible than vertebrate filaments and have an alanine at this position (A167). Substitution of this alanine for a glutamic acid (A167E) confers Saccharomyces cerevisiae actin filaments with salt-dependent stiffness similar to vertebrate actins. We developed an optimized cryogenic electron microscopy workflow refining sample preparation and vitrification to obtain near-atomic resolution structures of wild-type and A167E mutant Saccharomyces cerevisiae actin filaments. The difference between these structures allowed us to pinpoint the potential binding site of a filament-associated cation that controls the stiffness of the filaments in vertebrate and A167E Saccharomyces cerevisiae actins. Through an analysis of previously published high-resolution reconstructions of vertebrate actin filaments, along with a newly determined high-resolution vertebrate actin structure in the absence of potassium, we identified a unique peak near residue 167 consistent with the binding of a magnesium ion. Our findings show how magnesium can contribute to filament stiffening by directly bridging actin subunits and allosterically affecting the orientation of the DNase-I binding loop of actin, which plays a regulatory role in modulating actin filament stiffness and interactions with regulatory proteins.

Adsorptive removal of phosphate from water with biochar from acacia tree modified with iron and magnesium oxides

A novel biochar (BC) from Acaciatortilis trees pruning waste was synthesized and tested for the removal of phosphate from aqueous solutions. The BC was prepared by calcination at 600 °C and doped with Fe3O4 and MgO by hydrothermal process. The presence of iron and magnesium ions in the modified BC was confirmed by EDS analysis and X-ray diffraction (XRD) methods. Both unmodified and doped BCs were tested for phosphate removal from synthetic 1–500 ppm aqueous solutions. While the unmodified BC did not show any significant removal of phosphate from aqueous solutions, the modified BC almost completely removed phosphate from water. The enhancement in removal efficiency is due to an increase in the overall surface charge and surface area of BC as a result of doping with Fe3O4 and MgO salts. The average porosity and BET surface area corresponding to the plain BC increased by more than 20% from 322 to 394 m2/g after modification by impregnation with iron oxide and magnesium oxide. The modificaiton of BC with Fe3O4 and MgO nanoparticles was observed to increase the point of zero electric charge (PZC) from pH 3.4 (corresponding to plain BC) to pH 5.3 (corresponding to modified BC). The adsorption process was very fast and a phosphate removal value of 82.5% was reached only after 30 min of adsorption, while the removal efficiency after 4 h of adsorption was 97.5%. The rapid removal efficiency in short contact time is attributed to the high surface area of BC and strong bonding between the modified BC surface and PO43− ions. The highest adsorption capacity was observed to correspond to 98.5 mg/g which was achieved at PO43− concentration of 500 ppm and pH 8.5. Moreover, after fitting the adsorption data onto four of the most widely used adsorption isotherm models, the adsorption of PO43− onto BC can be better described by the Langmuir isotherm model.

Bioactive nanocomposite hydrogel enhances postoperative immunotherapy and bone reconstruction for osteosarcoma treatment

Osteosarcoma, a malignant bone tumor often characterized by high hedgehog signaling activity, residual tumor cells, and substantial bone defects, poses significant challenges to both treatment response and postsurgical recovery. Here, we developed a nanocomposite hydrogel for the sustained co-delivery of bioactive magnesium ions, anti-PD-L1 antibody (αPD-L1), and hedgehog pathway antagonist vismodegib, to eradicate residual tumor cells while promoting bone regeneration post-surgery. In a mouse model of tibia osteosarcoma, this hydrogel-mediated combination therapy led to remarkable tumor growth inhibition and hence increased animal survival by enhancing the activity of tumor-suppressed CD8+ T cells. Meanwhile, the implanted hydrogel improved the microenvironment of osteogenesis through long-term sustained release of Mg2+, facilitating bone defect repair by upregulating the expression of osteogenic genes. After 21 days, the expression levels of ALP, COL1, RUNX2, and BGLAP in the Vis-αPD-L1-Gel group were approximately 4.1, 5.1, 5.5, and 3.4 times higher than those of the control, respectively. We believe that this hydrogel-based combination therapy offers a potentially valuable strategy for treating osteosarcoma and addressing the tumor-related complex bone diseases.

Multifunctional Sr,Mg-Doped Mesoporous Bioactive Glass Nanoparticles for Simultaneous Bone Regeneration and Drug Delivery.

Mesoporous bioactive glass nanoparticles (MBGNs) doped with therapeutical ions present multifunctional systems that enable a synergistic outcome through the dual delivery of drugs and ions. The aim of this study was to evaluate influence of co-doping with strontium and magnesium ions (SrMg-MBGNs) on the properties of MBGNs. A modified microemulsion-assisted sol-gel synthesis was used to obtain particles, and their physicochemical properties, bioactivity, and drug-loading/release ability were evaluated. Indirect biological assays using 2D and 3D cell culture models on human bone marrow-derived mesenchymal stem cells (hBM-MSCs) and endothelial EA.hy926 cells, respectively, were used to determine biocompatibility of MBGNs, their influence on alkaline phosphatase (ALP) production, calcium deposition, and cytoskeletal organization. Results showed that Sr,Mg-doping increased pore volume and solubility, and changed the mesoporous structure from worm-like to radial-dendritic, which led to a slightly accelerated drug release compared to pristine MBGNs. Biological assays confirmed that particles are biocompatible, and have ability to slightly induce ALP production and calcium deposition of hBM-MSCs, as well as to significantly improve the proliferation of EA.hy926 compared to biochemical stimulation via vascular endothelial growth factor (VEGF) administration or regular media. Fluorescence staining revealed that SrMg-MBGNs had a similar effect on EA.hy926 cytoskeletal organization to the VEGF group. In conclusion, Sr,Mg-MBGNs might be considered promising biomaterial for biomedical applications.

Determination of nutrient concentration in liquid culture of cyanobacteria Nostoc sp. by capillary electrophoresis and inductively coupled plasma mass spectrometry

In this work, we demonstrate the use of capillary electrophoresis and inductively coupled plasma mass spectrometry, as competitive methods primarily for ion chromatography, to determine changes in the concentration of small inorganic ions in the Nostoc sp. culture medium. Although macronutrients were analyzed by capillary electrophoresis with conductivity detection, micronutrients were analyzed by inductively coupled plasma mass spectrometry. The different light settings (light intensity and spectral composition) had a visible effect on the culture growth and depletion of calcium, magnesium, and phosphate ions, and iron and manganese elements when comparing the behavior under red or violet light with that under blue light.

Magnesium-enriched deep-sea water inhibits NLRP3 inflammasome activation and dampens inflammation

The NLRP3 inflammasome is an essential component of the innate immune system, but excessive activation can lead to inflammatory diseases. Ion fluxes across the plasma membrane or from intracellular stores are known to regulate NLRP3 inflammasome activation. Deep-sea water (DSW) contains high concentrations of many mineral ions, which could potentially influence NLRP3 inflammasome activation. However, the impact of DSW on NLRP3 inflammasome activation has not been investigated. Here, we demonstrated that DSW with water hardness levels up to 500 mg/L did not affect cell viability or the expression of NLRP3 inflammasome components in macrophages derived from THP-1 cells. However, the DSW significantly inhibited IL-1β secretion and caspase-1 activation in response to NLRP3 activators such as nigericin, ATP, or monosodium urate (MSU) crystals. Mechanically, it was discovered that the presence of 5 mM magnesium ions (Mg2+), equivalent to the Mg2+ concentration found in the DSW with a water hardness of 500 mg/L, inhibits NLRP3 inflammasome activation. This indicates that Mg2+ contributes to the mechanism by which DSW mitigates NLRP3 inflammasome activation. Moreover, DSW administration effectively lessens MSU-triggered peritonitis in mice, a commonly used model for examining the impacts of NLRP3 inflammasome activation. These results show that DSW enriched with Mg2+ could potentially be beneficial in modulating NLRP3 inflammasome-associated diseases.

Biosafety and osteogenic properties of a new type of absorbable magnesium-based amorphous alloy

The treatment of bone defects has always been a difficult problem in orthopedic clinical practice, and research on new materials is currently a hot topic. In this study, the biological safety and bone induction ability of a new magnesium-based amorphous alloy (Mg66Zn30Ca3Sr1) and zinc–magnesium powder were verified and compared in animal experiments. Thirty Sprague–Dawley rats were randomly divided into three groups, and a bone defect was made in the lateral condyle of the femur of the left hind limb. The blank group closed the wound after establishing the bone defect model, the control group added zinc–magnesium powder and chondroitin sulfate gel, and the experimental group added magnesium–zinc–calcium–strontium alloy and chondroitin sulfate gel with the same volume. Peripheral venous blood of rats was collected at 4, 8, and 12 weeks postoperatively, and alanine aminotransferase (ALT), aspartate transferase, creatinine, blood urea nitrogen, magnesium ion, and zinc ion levels were evaluated. The expression levels of bone morphogenetic protein 2 (BMP-2), osteoprotegerin (OPG), osteopontin (OPN), core binding factor α1 (RUNX2), and alkaline phosphatase (ALP) were detected using enzyme-linked immunosorbent assay (ELISA). After the rats were euthanized, samples were taken. X-rays and micro-computed tomography (CT) images of the bone defect were obtained, and hematoxylin and eosin and Masson staining were performed. This study shows that amorphous magnesium–zinc–calcium–strontium alloy is a biodegradable metal with good biocompatibility and bone induction and has good application prospects in treating bone defects.

Synthesis of eco-sustainable seawater sea-sand geopolymer mortars from ternary solid waste: Influence of microstructure evolution on mechanical performance

To fully utilize abundant marine resources and reduce the carbon footprint in the construction sector, this study developed a seawater sea-sand geopolymer mortar (SSGM) using seawater, sea-sand, and ternary solid waste. Three different alkaline content levels (4%, 5%, and 7%) were tailored for the SSGM, in addition to freshwater river sand mixed geopolymer mortars (FRGM), seawater sea-sand ordinary Portland cement mortar (SSCM), and SSGM without additional fibres (SSGM-0). The workability, setting time, mechanical performance, and drying shrinkage of all samples were studied. The microstructural characteristics of each mortar were meticulously scrutinized through techniques including X-ray diffraction (XRD), scanning electron microscopy (SEM), Fourier transform infrared (FTIR) spectroscopy, and mercury intrusion porosimetry (MIP). The results showed that as alkaline content increased, SSGM formed more hybrid sodium, calcium aluminosilicate hydrate (N, C-A-S-H) gels, resulting in a denser matrix. Under the influence of magnesium ions and sulfate ions in seawater, the formation of magnesium aluminosilicate hydrates, magnesium silicate hydrates, and silica gels filled the pores, making SSGM has more mesopores and gel pores compared to FRGM, thus exhibiting superior mechanical properties. However, the Ca/Si ratio of the primary hydration products of SSGM was lower than that of SSCM and FRGM, indicating a more disordered microstructure of SSGM, leading to greater shrinkage. Despite moisture migration reaching a stable state, SSGM exhibited persistent shrinkage, revealing their inherent time-dependent (creep) response to drying conditions, indicative of typical viscoelastic/visco-plastic matrix behavior.

Progress and Prospect of Sn‐based Metal‐organic Framework Derived Anode Materials for Metal‐ion Batteries

AbstractIn order to realize the growing demand for superior energy storage devices and electric vehicles, commercial anode candidates for next‐generation rechargeable batteries need to meet the characteristics of low cost, high energy density, high capacity, and stable performance. The emerging tin‐based anodes show great potential for high performance metal‐ion battery anodes due to their high theoretical capacity, low cost, green harmless and high safety. Tin based anode materials include tin gold based materials, tin alloy materials, tin based oxides, tin based phosphide, tin based sulfides, multi‐component composite materials, etc. However, the change in volume and structure of tin‐based anode materials during the cycle has become the biggest obstacle to its development. Metal‐organic frameworks (MOFs) provide a wide range of possibilities for achieving high rate capacity and excellent cycle stability by finely regulating the structure and composition of tin‐based materials at the molecular level. The latest progress of tin‐based materials derived from MOFs as anode materials for metal‐ion batteries (including lithium ion batteries, sodium ion batteries, potassium ion batteries, magnesium ion batteries) was reviewed in this paper. Firstly, the preparation method and morphology control of tin‐based MOF are briefly introduced, and the structural characteristics, storage mechanism and modification of tin‐based MOF derived materials are emphatically discussed. Finally, we summarized the existing modification measures and challenges of these anode materials, and put forward the prospect of the future.

In Situ Growth Method for Large-Area Flexible Perovskite Nanocrystal Films.

Metal halide perovskites have shown unique advantages compared with traditional optoelectronic materials. Currently, perovskite films are commonly produced by either multi-step spin coating or vapor deposition techniques. However, both methods face challenges regarding large-scale production. Herein, we propose a straightforward in situ growth method for the fabrication of CsPbBr3 nanocrystal films. The films cover an area over 5.5 cm × 5.5 cm, with precise thickness control of a few microns and decent uniformity. Moreover, we demonstrate that the incorporation of magnesium ions into the perovskite enhances crystallization and effectively passivates surface defects, thereby further enhancing luminous efficiency. By integrating this approach with a silicon photodiode detector, we observe an increase in responsivity from 1.68 × 10-2 A/W to 3.72 × 10-2 A/W at a 365 nm ultraviolet wavelength.

CRISPR-Cas12a exhibits metal-dependent specificity switching.

Cas12a is the immune effector of type V-A CRISPR-Cas systems and has been co-opted for genome editing and other biotechnology tools. The specificity of Cas12a has been the subject of extensive investigation both in vitro and in genome editing experiments. However, in vitro studies have often been performed at high magnesium ion concentrations that are inconsistent with the free Mg2+ concentrations that would be present in cells. By profiling the specificity of Cas12a orthologs at a range of Mg2+ concentrations, we find that Cas12a switches its specificity depending on metal ion concentration. Lowering Mg2+ concentration decreases cleavage defects caused by seed mismatches, while increasing the defects caused by PAM-distal mismatches. We show that Cas12a can bind seed mutant targets more rapidly at low Mg2+ concentrations, resulting in faster cleavage. In contrast, PAM-distal mismatches cause substantial defects in cleavage following formation of the Cas12a-target complex at low Mg2+ concentrations. We observe differences in Cas12a specificity switching between three orthologs that results in variations in the routes of phage escape from Cas12a-mediated immunity. Overall, our results reveal the importance of physiological metal ion conditions on the specificity of Cas effectors that are used in different cellular environments.

Progress and Challenges of Vanadium Oxide Cathodes for Rechargeable Magnesium Batteries.

Among the challenges related to rechargeable magnesium batteries (RMBs) still not resolved are positive electrode materials with sufficient charge storage and rate capability as well as stability and raw material resources. Out of the materials proposed and studied so far, vanadium oxides stand out for these requirements, but significant further improvements are expected and required. They will be based on new materials and an improved understanding of their mode of operation. This report provides a critical review focused on this material, which is embedded in a brief overview on the general subject. It starts with the main strategic ways to design layered vanadium oxides cathodes for RMBs. Taking these examples in more detail, the typical issues and challenges often missed in broader overviews and reviews are discussed. In particular, issues related to the electrochemistry of intercalation processes in layered vanadium oxides; advantageous strategies for the development of vanadium oxide composite cathodes; their mechanism in aqueous, "wet", and dry non-aqueous aprotic systems; and the possibility of co-intercalation processes involving protons and magnesium ions are considered. The perspectives for future development of vanadium oxide-based cathode materials are finally discussed and summarized.

Thermal-Responsive Antibacterial Hydrogel with Photothermal Therapy and Improving Wound Microenvironment for Promote Healing.

Skin damage is one of the most prevalent human injuries, which affects the health of human beings. However, skin damage is often accompanied by bacterial infection and wound microenvironment changes, causing damage to normal cells and inhibiting wound healing. Herein, we designed a thermal-responsive antibacterial hydrogel (GAG hydrogel) loaded with catalase (CAT)-like Au@Pt@MgSiO3 nanoparticles (APM NPs) and gentamicin (GM) to promote wound healing. The GAG hydrogel was used in a photothermal therapy (PTT)/antibiotic combination to kill bacteria, reduce the use of antibiotics, improve the wound microenvironment, promote cell proliferation, and accelerate wound healing. Under near-infrared laser irradiation, APM NPs in the hydrogel generated local hyperthermia to kill bacteria. Meanwhile, the generated heat led to a change in the hydrogel's morphology, enabling it to release GM and APM NPs to prevent the overuse of antibiotics. Subsequently, the CAT-like ability of the APM NPs decreased the oxidative stress caused by hydrogen peroxide (H2O2), thus remodeling the wound microenvironment. Then, the weakly acidic microenvironment of the wound caused the decomposition of the APM NPs and the release of magnesium ions (Mg2+), promoting the growth and migration of cells for wound healing. Therefore, the studied thermal-responsive antibacterial (GAG) hydrogel has potential in the field of wound healing.

Investigation of COVID-19 virus mutagenicity and the effect of the NSP13, NSP14, and NSP16 on the -1 ribosomal frameshifting

The COVID-19 virus is a single-stranded virus from the Coronaviridae family and has a genome of about 29881 bp, which causes acute respiratory disease. One way of transmission of the COVID-19 virus is respiratory, which is the reason for the significant transmission of the disease. The COVID-19 virus causes mutagenesis in different parts of the virus genome with its mechanisms, including -1 ribosomal frameshifting. Various parts that have undergone the most severe mutations include the spike protein, which leads to the emergence of new variants. Most of the mutations observed in the COVID-19 virus are located in the S protein and a region known as the RBD (Receptor-Binding Domain), which binds to the ACE2 (Angiotensin-converting enzyme 2) receptor in human cells. The variations in the RBD region will determine how it binds to the ACE2 receptor. Essentially, the changes created because of the mutation determine the affinity of the RBD to ACE2. On the other hand, the COVID-19 virus, because of its NSP13, NSP14, and NSP16 proteins, helps the mutation of the virus by consuming magnesium ions (Mg2+). Since the ribosome is stable with Mg2+, the COVID-19 virus, by consuming Mg2+, causes the ribosome to convert from the polysome to the monosome state, which causes a break in translation and finally leads to the formation of -1 ribosomal frameshifting.