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Nanomaterials, with their small size, surface characteristics, and antibacterial properties, are extensively employed across environmental, energy, biomedical, agricultural, and other industries. This study examined the antibacterial efficacy of magnesium hydroxide (Mg(OH) 2 ) nanoparticles (NPs) against sulfate-reducing bacteria (SRB) within sediments. The inhibitory effects of two types of Mg(OH) 2 NPs with distinct particle sizes (20.3 and 29.6 nm) and concentrations (0–10.0 mg/mL) were examined under optimal treatment conditions. The antibacterial mechanisms of Mg(OH) 2 NPs through direct contact and dissolution effects were determined. The results revealed a correlation between the concentration, particle size, and inhibitory activity, with the smallest NPs (20.3 nm) at the highest concentration (10.0 mg/mL) substantially reducing SRB counts from 8.77 ± 0.18 to 6.48 ± 0.13 log 10 colony forming units/mL after 6 h treatment. Treatment with high concentrations of Mg(OH) 2 NPs induced cellular damage, reduced intracellular lactate dehydrogenase activity, and elevated intracellular catalase activity and H 2 O 2 content, suggesting that the contact effect of NPs stimulated SRB. This leads to oxidative stress response and structural damage to the cell membrane, which has emerged as the primary driver of the antibacterial action of Mg(OH) 2 NPs. This study presents a novel nanomaterial that can inhibit and control SRB in natural sedimentary environments.

The silver, magnesium oxide and gyrotactic microorganism-based hybrid nanofluid flow inside the conical space between disc and cone is addressed in the perspective of thermal energy stabilization. Different cases have been discussed between the spinning of cone and disc in the same or counter wise directions. The hybrid nanofluid has been synthesized in the presence of silver Ag and magnesium oxide MgO nanoparticulate. The viscous dissipation and the magnetic field factors are introduced to the modeled equations. The parametric continuation method (PCM) is utilized to numerically handle the modeled problem. Magnesium oxide is chemically made up of Mg 2+ and O 2- ions that are bound by a strong ionic connection and can be made by pyrolyzing Mg(OH) 2 (magnesium hydroxide) and MgCO 3 (magnesium carbonate) at high temperature (700–1500 °C). For metallurgical, biomedical and electrical implementations, it is more efficient. Similarly, silver nanoparticle's antibacterial properties could be employed to control bacterial growth. It has been observed that a circulating disc with a stationary cone can achieve the optimum cooling of the cone-disk apparatus while the outer edge temperature remains fixed. The thermal energy profile remarkably upgraded with the magnetic effect, the addition of nanoparticulate in base fluid and Eckert number.

Layered double hydroxides (LDHs), also known as anionic nanoclays or hydrotalcite-like compounds, have attracted a great deal of interest for their potential as delivery carriers. In this article, we describe the cellular uptake behaviors and uptake pathway of LDHs and , which can not only explain the mechanism by which high efficacy of biomolecules delivered through LDH nanocarriers could be obtained, but also provide novel strategies to enhance their delivery efficiency. Toxicological effects of LDHs in cell lines and in animal models are also present, aiming at providing critical information about their toxicity potential, which should be carefully considered for their biomedical application. Understanding the uptake behaviors, uptake mechanism and toxicity of LDHs in terms of dose-–response relationship, diverse physicochemical properties and interaction with different biological systems is important to optimize delivery efficiency as well as biocompatibility.

The study investigates the utilization of okra mucilage as an encapsulating agent for the development of magnesium hydroxide nano-capsules for oral drug delivery systems. Given the advancements in drug delivery systems (DDSs) and the emerging interest in nanostructured drug delivery systems (NDDSs), the potential of okra mucilage for nanoencapsulation is explored. NDDSs hold promise for enhancing therapeutic efficacy while minimizing adverse effects. Okra mucilage is known for its biodegradability, non-toxicity, and cost-effectiveness, making it a suitable candidate for encapsulation processes. The sol–gel encapsulation method is employed to fabricate the encapsulated magnesium hydroxide particles (EMgPs). The EMgPs were characterized using XRD, FT-IR, Raman spectroscopy, and FESEM/EDS, confirming the successful encapsulation of magnesium hydroxide within the okra mucilage. The hydrophilic properties of the EMgPs were also assessed through contact angle measurements, revealing promising wettability for efficient drug release in the digestive system. Release tests in a simulated digestive system environment demonstrated a controlled and sustained release profile (zero-order release) of magnesium hydroxide from the EMgPs with a rate constant of 0.75 and 0.2894 mg mL −1  h −1 in gastric phase and intestinal phase, respectively. The findings highlight the potential of okra mucilage as an encapsulating agent in oral drug delivery systems and provide insights for further research in the field of nanomedicine.

Ultramafic rocks undergo successive stages of hydration and oxidation during water/rock interaction, giving rise to secondary minerals such as brucite, serpentine, magnetite and the production of H 2(g) . Ferroan brucite ( M g x Fe ( 1 − x ) 2 + ( OH ) 2 ) often forms under low water/rock ratios early during the ‘serpentinization’ process. The formation of ferroan brucite sequesters Fe(II) and suppresses the production of H 2 , thereby limiting the flux of reductants suitable for sustaining microbial metabolism. Yet ferroan brucite is a relatively soluble mineral ‘reservoir’ for reactive Fe(II). Brucite is often metastable and can be lost at later stages of peridotite hydration when there is a significant increase in the water/rock ratio or the activity of SiO 2 or CO 2 . The Fe(OH) 2 component of brucite has the thermodynamic potential to reduce most aqueous oxidants. Therefore, ferroan brucite may reduce water and/or dissolved carbon, nitrogen and sulfur species, while the Fe(II) is converted into more stable secondary minerals such as Fe(II/III)-oxides and hydroxides (e.g. green-rust, magnetite, iowaite and pyroaurite) and ferric serpentine. The reactivity of ferroan brucite, and the associated rate of Fe solubilization and oxidation in subsurface fluids, could be a key regulator on the rate of electron transfer from serpentinites to the rock-hosted biosphere. Aqueous alteration of ferroan brucite may significantly modulate the H 2 activity in fluids circulating within partially serpentinized rocks, and buffer H 2 as it is lost by advection or in situ consumption by a hydrogenotrophic microbial community. Moreover, there may be microbial organisms that specifically colonize and use ferroan brucite as an electron donor for their metabolism. The energy fluxes sustained by localized brucite oxidation may often be sufficiently large to sustain abundant microbial communities; water/rock reaction zones where brucite is consumed could serve as environments to search for extant or fossil serpentinite-hosted life. This article is part of a discussion meeting issue ‘Serpentinite in the Earth System’.

This study presents an innovative, and environmentally friendly synthesis process for spike spherical magnesium hydroxide (SSMH) using magnesite and an ammonia-cycle method, which eliminates waste liquid, gas, and chemical reagent pollution. The process involves calcining magnesite to obtain calcined magnesite, which reacts with (NH 4 ) 2 SO 4 to produce magnesium sulfate and ammonia. Subsequently, magnesium sulfate reacts with ammonia water to generate SSMH. The optimized conditions for the extraction of magnesium ion (Mg²⁺) are as follows: (NH 4 ) 2 SO 4 concentration of 2.4 mol/L, 4 g of calcined magnesite powder, and a reaction time of 1.5 h, resulting in an extraction rate of Mg²⁺ of 93.4%. The optimized conditions for the precipitation of Mg² ⁺ are as follows: Mg² ⁺ concentration of 0.7–1.3 mol/L, NH₃H₂O/Mg² ⁺ molar ratio of 9, reaction temperature of 60°C, and reaction time of 1 h, with a precipitation rate of Mg²⁺ of about 85%. After five ammonia cycles, the precipitation rate of Mg² ⁺ stabilizes at 85%. Scanning Electron Microscopy (SEM) confirms the spike spherical structure of the SSMH, with uniform particle diameters and a particle size of 2 μm. Adsorption studies indicate a maximum adsorption capacity (Q m ) of 150.4944 mg/g for Reactive Red X-3B (RRX) dye at 25°C, fitting well with the Langmuir and pseudo-second-order kinetic model. The adsorption is primarily chemisorption-driven. In conclusion, the ammonia-cycle method for SSMH from magnesite is an environmentally friendly and sustainable approach. SSMH with its high adsorption capacity and spike spherical structure, is effective for treating RRX aqueous solution and has potential for broader applications in removing heavy metals, persistent organic compounds, nitrogen, and phosphorus from various polluted sources.

•Newly developed esomeprazole/magnesium hydroxide fixed-dose combination (FDC) exhibits faster time to reach maximum concentration compared to enteric-coated esomeprazole.•The FDC demonstrates a shorter time to achieve gastric pH ≥ 4, indicating more rapid and effective acid suppression compared to enteric-coated esomeprazole.•Comparable systemic exposure and decrease in integrated gastric acidity over 24 hours highlight equivalent inhibition of gastric acid secretion between the FDC and enteric-coated esomeprazole.•The esomeprazole/magnesium hydroxide FDC presents as a promising option with faster absorption and effective gastric acid suppression, offering potential clinical advantages over enteric-coated esomeprazole. A fixed-dose combination (FDC) of proton pump inhibitors (PPIs) and antacid salts enables rapid acid suppression through the neutralizing effect of the antacid salt and the rapid absorption of PPIs. This study aimed to compare the pharmacokinetics (PKs) and pharmacodynamics (PDs) of a recently formulated FDC of esomeprazole and magnesium hydroxide to the enteric-coated esomeprazole in healthy subjects. A randomized, open-label, multiple-dose, two-treatment, two-way crossover design was conducted in healthy subjects. Forty-nine subjects were randomized to one of the two treatment sequences and received either the test drug (esomeprazole/magnesium hydroxide 40/350 mg) or reference drug (enteric-coated esomeprazole 40 mg) for 7 days in the first period and the alternative in the second period with a 14-day washout period. Blood samples were collected for up to 24 hours for PK assessment, and 24-hour gastric pH monitoring was conducted for PD assessment both before and after a single administration, as well as at a steady state after seven consecutive days of administration. The PK and PD parameters were compared between the two drugs. After multiple administrations, the median value of time to reach maximum concentration was faster in the test drug than in the reference drug, with a difference of 1.68 hours. The overall systemic exposure of the test drug was similar to that of the reference drug, and the PK parameter fell within the equivalence criteria. The test drug demonstrated a shorter time to reach gastric pH ≥ 4 compared to the reference drug (P = 0.0463). A decrease from baseline in integrated gastric acidity over 24 hours, which represents the degree of inhibition of gastric acid secretion, was equivalent between the two drugs. The fixed-dose combination of esomeprazole and magnesium hydroxide showed rapid absorption and quicker gastric acid suppression than enteric-coated esomeprazole with comparable PK and PD properties. ClinicalTrials.gov identifier: NCT04324905 (https://classic.clinicaltrials.gov/ct2/show/NCT04324905).

Polylactic acid (PLA) has attracted much attention in bone tissue engineering due to its good biocompatibility and processability, but it still faces problems such as a slow degradation rate, acidic degradation product, weak biomineralization ability, and poor cell response, which limits its wider application in developing bone scaffolds. In this study, Mg(OH)2 nanoparticles were employed as a versatile nanofiller for developing PLA/Mg(OH)2 composite bone scaffolds using fused deposition modeling (FDM) 3D printing technology, and its mechanical, degradation, and biological properties were evaluated. The mechanical tests revealed that a 5 wt% addition of Mg(OH)2 improved the tensile and compressive strengths of the PLA scaffold by 20.50% and 63.97%, respectively. The soaking experiment in phosphate buffered solution (PBS) revealed that the alkaline degradation products of Mg(OH)2 neutralized the acidic degradation products of PLA, thus accelerating the degradation of PLA. The weight loss rate of the PLA/20Mg(OH)2 scaffold (15.40%) was significantly higher than that of PLA (0.15%) on day 28. Meanwhile, the composite scaffolds showed long-term Mg2+ release for more than 28 days. The simulated body fluid (SBF) immersion experiment indicated that Mg(OH)2 promoted the deposition of apatite and improved the biomineralization of PLA scaffolds. The cell culture of bone marrow mesenchymal stem cells (BMSCs) indicated that adding 5 wt% Mg(OH)2 effectively improved cell responses, including adhesion, proliferation, and osteogenic differentiation, due to the release of Mg2+. This study suggests that Mg(OH)2 can simultaneously address various issues related to polymer scaffolds, including degradation, mechanical properties, and cell interaction, having promising applications in tissue engineering.

Magnesium oxide (MgO) and hydroxide [Mg(OH)2] are conventionally considered insoluble in water and stable at high temperatures. However, in this study, we found significant dissociation of MgO and Mg(OH)2 into ions when they were immersed in different physiologically relevant solutions in the form of 20-nm and 10-nm nanoparticles respectively, under standard cell culture conditions in vitro, i.e., a 37 °C, 5% CO2/95% air, sterile, humidified environment. The change in Mg2+ ion concentrations and pH measured in the physiologically relevant solutions (e.g., Dulbecco’s modified Eagle’s Medium (DMEM), simulated body fluid (SBF), relevant chloride solutions, and deionized water) confirmed their dissociation. Possible mechanisms and contributing factors for dissociation of MgO and Mg(OH)2 nanoparticles were discussed. The evidence suggests that nucleophilic substitution of OH− by Cl− in Mg(OH)2 is energetically unfavorable and it is more likely that Cl− plays a role in the stabilization of intermediate forms of MgO and Mg(OH)2 as it dissociates. The pH and buffering capability of the immersion solutions might have played the most significant role in dissociation of these nanoparticles when compared with the roles of chloride (Cl−), proteins, and different buffering agents. This article provided the first evidence on the dissociation of MgO and Mg(OH)2 nanoparticles in physiologically relevant conditions and elucidated possible factors contributing to the observed behaviors of these nanoparticles in vitro, which is important for their potential medical applications in vivo.

A functional magnesium hydroxide/lignin hybrid system was prepared by grinding and mixing the pure precursors using a planetary ball mill. In addition, the thermal stability was assessed based on the total mass loss of the hybrid system within the temperature range of 30–1000 °C, which amounted to 38%. Moreover, the average particle size was at 4.9 μm as determined by the laser diffraction method. The effect of addition of the prepared and characterized Mg(OH)2/lignin hybrid filler at concentrations ranging from 2.5 wt % to 10 wt % on the processing as well as mechanical and thermal properties of composites on the matrix of the unplasticized PVC compound was also evaluated. The addition of a filler to the poly(vinyl chloride) matrix causes a significant improvement of its thermal stability, which is approximately three times higher compared to a polymer without a filler. Furthermore, the prepared composites are additionally characterized by advantageous mechanical properties, especially higher Young’s modulus. A 10% increase in the oxygen index of PVC composites upon addition of 10 wt % hybrid fillers has also been observed, which contributes to an extended range of their application under conditions that require notable fire resistance.