Pristine/magnesium-loaded biochar and ZVI affect rice grain arsenic speciation and cadmium accumulation through different pathways in an alkaline paddy soil.

Cadmium (Cd) and arsenic (As) co-contamination has threatened rice production and food safety. It is challenging to mitigate Cd and As contamination in rice simultaneously due to their opposite geochemical behaviors. Mg-loaded biochar with outstanding adsorption capacity for As and Cd was used for the first time to remediate Cd/As contaminated paddy soils. In addition, the effect of zero-valent iron (ZVI) on grain As speciation accumulation in alkaline paddy soils was first investigated. The effect of rice straw biochar (SC), magnesium-loaded rice straw biochar (Mg/SC), and ZVI on concentrations of Cd and As speciation in soil porewater and their accumulation in rice tissues was investigated in a pot experiment. Addition of SC, Mg/SC and ZVI to soil reduced Cd concentrations in rice grain by 46.1%, 90.3% and 100%, and inorganic As (iAs) by 35.4%, 33.1% and 29.1%, respectively, and reduced Cd concentrations in porewater by 74.3%, 96.5% and 96.2%, respectively. Reductions of 51.6% and 87.7% in porewater iAs concentrations were observed with Mg/SC and ZVI amendments, but not with SC. Dimethylarsinic acid (DMA) concentrations in porewater and grain increased by a factor of 4.9 and 3.3, respectively, with ZVI amendment. The three amendments affected grain concentrations of iAs, DMA and Cd mainly by modulating their translocation within plant and the levels of As(III), silicon, dissolved organic carbon, iron or Cd in porewater. All three amendments (SC, Mg/SC and ZVI) have the potential to simultaneously mitigate Cd and iAs accumulation in rice grain, although the pathways are different.

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.

Causal Effect of Macronutrient and Micronutrient Intake on Stroke: A Two-Sample Mendelian Randomization Study.

(1) Background: Estimating the causal association between nutrient intake, as a modifiable risk factor, and stroke risk is beneficial for the prevention and management of stroke. However, observational studies are unavoidably influenced by confounding factors and reverse causation. (2) Methods: We performed a two-sample Mendelian randomization (MR) to estimate the effects of nutrient intake on stroke risk. Summary statistics for nutrients, including 4 macronutrients and 14 micronutrients, were derived from 15 genome-wide association studies (GWAS). Data on stroke and its subtypes were sourced from the MEGASTROKE consortium. (3) Results: Genetically predicted magnesium levels, as the protective factors, were significantly associated with a lower risk of cardioembolic stroke (OR: 0.011, 95% CI: 0-0.25, p-value: 0.005) in the IVW method. Additionally, vitamin C reduced the risk of cardioembolic stroke (OR: 0.759, 95% CI: 0.609-0.946, p-value: 0.014) and vitamin B9 reduced the risk of small vessel stroke (OR: 0.574, 95% CI: 0.393-0.839, p-value: 0.004) with the IVW method. However, the association of vitamin B6 with an increased risk of large-artery stroke (OR: 1.546, 95% CI: 1.009-2.37, p-value: 0.046) in the Wald ratio method should be interpreted cautiously due to the limited number of SNPs. There was also suggestive evidence that magnesium might decrease the risk of both any stroke and ischemic stroke. (4) Conclusions: Our MR analysis highlights the protective roles of magnesium, vitamin C, and vitamin B9 in stroke prevention, making them key targets for public health strategies. However, the findings related to vitamin B6 are less certain and require further validation.

The Evaluation of Selected Trace Elements in Blood, Serum and Blood Cells of Type 2 Diabetes Patients with and without Renal Disorder.

BACKGROUND: An appropriate diet is the basis for the treatment of type 2 diabetes (T2DM). However, there are no strict recommendations regarding the content of micronutrients and their modifications in the presence of chronic kidney disease (CKD). Therefore, we decided to investigate whether T2DM patients, including those with CKD, have different levels of chromium, nickel, cobalt, magnesium, and zinc in various blood elements compared to healthy individuals. METHODS: We divided our subjects into three groups: the control group (individuals without T2DM and proper renal function), those with T2DM and proper renal function, and those with T2DM and GFR < 60 mL/min/1.73 m2. RESULTS: We observed higher levels of chromium in all materials examined in patients with T2DM and impaired renal function. Both study groups found higher levels of nickel in samples of whole blood and red blood cells. Patients with T2DM and proper renal function had higher levels of serum manganese. Both study groups had lower levels of serum zinc. We observed higher levels of chromium in all materials examined in patients with T2DM and impaired renal function. Both study groups found higher levels of nickel in samples of whole blood and red blood cells. Patients with T2DM and proper renal function had higher levels of serum manganese. Both study groups had lower levels of serum zinc. CONCLUSIONS: In order to ensure effective care for patients with T2DM, it is necessary to improve the standard diet, including the content of micronutrients and their modification in patients with concomitant CKD.

Abnormal serum Magnesium Level is Associated with the Coagulopathy in Traumatic Brain Injury Patients.

BACKGROUND: Coagulopathy is associated with poor prognosis of traumatic brain injury (TBI) patients. This study is performed to explore the association between serum magnesium level and the risk of coagulopathy in TBI. METHODS: TBI patients from the Medical Information Mart for Intensive Care-III database were included for this study. Logistic regression analysis was performed to explore risk factors and develop a predictive model for coagulopathy in TBI. The restricted cubic spline (RCS) was utilized to analyze the association between serum magnesium level and the development of coagulopathy. Receiver operating characteristic curve was drawn to evaluate the performance of the predictive model for coagulopathy. RESULTS: The incidence of coagulopathy in TBI was 32.6%. The RCS indicated the association between magnesium and coagulopathy was U-shaped. Multivariate logistic regression confirmed age, coronary heart disease, cerebral vascular disease, chronic liver disease, GCS, ISS, epidural hematoma, hemoglobin, shock index and magnesium level were independently associated with the coagulopathy in TBI. Compared with patients of magnesium level between 1.7 and 2.3 mg/dL, those with magnesium level below 1.7 mg/dL or above 2.2 mg/dL had a higher risk of coagulopathy. CONCLUSION: Both hypermagnesemia and hypomagnesemia are associated with higher risk of coagulopathy in TBI patients. Physicians should pay more attention on preventing coagulopathy in TBI patients with hypomagnesemia or hypermagnesemia.

Evaluation of serum vitamin B12 and D, iron, ferritin, folate, calcium, phosphorus and magnesium levels in children in palliative care clinic: a single-center cross-sectional study.

BACKGROUND: Pediatric palliative care (PPC) patients are at an elevated risk of malnutrition. Nutritional inadequacy can also cause micronutrient deficiencies. These factors can lead to weight loss, stunted growth, and poor quality of life. Despite the prevalence of these issues, limited research exists in the micronutrient status of PPC patients. The purpose of this study was to determine the vitamin B12 and D, iron, ferritin, folate, calcium, phosphorus, and magnesium levels of PPC patients to contribute to a better understanding of their micronutrient needs as well as the appropriate management of diet and treatment approaches. METHODS: This was a single-center observational cross-sectional retrospective study. This study evaluated the levels of vitamin B12, 25-hydroxyvitamin D, iron, ferritin, folate, calcium, phosphorus, and magnesium in PPC patients. The patients were classified according to the Chronic Complex Conditions (CCC) v2 and then compared. RESULTS: A total of 3,144 micronutrient data points were collected from 822 hospitalizations of 364 patients. At least one micronutrient deficiency was identified in 96.9% of the patients. The most prevalent deficiencies were observed for iron, calcium, and phosphate. In addition, 25-hydroxyvitamin D deficiency was observed in one-third of patients. Calcium, magnesium, phosphorus, folate, and 25-hydroxyvitamin D were negatively correlated with age. CONCLUSION: The results of this study indicate that micronutrient deficiencies are highly prevalent in PPC patients. These findings have the potential to contribute to improvements in the nutritional and therapeutic management of patients.

[Risk Factors Analysis for Hypermagnesemia with Magnesium Oxide].

While decreased renal function is a known risk factor for hypermagnesemia caused by magnesium oxide (MgO), few studies have comprehensively investigated other contributing factors. In this study, the researchers analyzed the risk factors for hypermagnesemia development in 256 inpatients receiving MgO treatment at the Matsuyama Shimin Hospital. Multivariate analysis identified blood urea nitrogen ≧22 mg/dL, estimated glomerular filtration rate ≦43.1 mL/min, and MgO ≧1000 mg/d as risk factors. Additionally, the researchers' findings suggest a correlation between the number of risk factors and the incidence of hypermagnesemia, including the prevalence of Grade 3 cases. Interestingly, low body mass index emerged as a potential risk factor even in patients without the three identified factors. These findings highlight the importance for pharmacists to advocate for routine serum Mg level monitoring in patients with the risk factors identified in this study.

Novel Magnesium- and Silver-Loaded Dressing Promotes Tissue Regeneration in Cutaneous Wounds.

Wound healing is a dynamic process involving a complex interaction between many cells and mediators. Magnesium (Mg) is an essential element for cell stabilization. Mg was reported to stimulate the proliferation and migration of endothelial cells in angiogenesis in vitro. However, the function of Mg in wound healing is not known. We observed that the expression level of Mg in human wound tissue fluid was only 10% of that found in human blood serum. To confirm whether Mg is a suitable wound dressing material, we fabricated a Mg- or Mg-silver (Ag)-based polyethylene dressing to study its effect on wound healing. We observed that Mg and Ag were stably preserved in the constructed material and were able to be rapidly released in the moist environment. We also observed that the Mg-based dressing had good cellular compatibility without harmful extractables. Furthermore, Mg enhanced the antibacterial activity of Ag. In line with the observed increase in fibroblast migration in vitro, the Mg-Ag-based dressing improved acute and chronic wound repairs via an increase in neovascularization and basal cell proliferation. The present results show that a Mg-Ag-based coating can be manufactured as an optimal dressing for adjuvant wound therapy.

High-level succinic acid production by overexpressing a magnesium transporter in Mannheimia succiniciproducens.

Succinic acid (SA), a dicarboxylic acid of industrial importance, can be efficiently produced by metabolically engineered Mannheimia succiniciproducens. Although the importance of magnesium (Mg2+) ion on SA production has been evident from our previous studies, the role of Mg2+ ion remains largely unexplored. In this study, we investigated the impact of Mg2+ ion on SA production and developed a hyper-SA producing strain of M. succiniciproducens by reconstructing the Mg2+ ion transport system. To achieve this, optimal alkaline neutralizer comprising Mg2+ ion was developed and the physiological effect of Mg2+ ion was analyzed. Subsequently, the Mg2+ ion transport system was reconstructed by introducing an efficient Mg2+ ion transporter from Salmonella enterica. A high-inoculum fed-batch fermentation of the final engineered strain produced 152.23 ± 0.99 g/L of SA, with a maximum productivity of 39.64 ± 0.69 g/L/h. These findings highlight the importance of Mg2+ ions and transportation system optimization in succinic acid production by M. succiniciproducens.

Influence of Magnesium Ion Binding on the Adenosine Diphosphate Structure and Dynamics, Investigated by 31P NMR and Molecular Dynamics Simulations.

Magnesium (Mg2+) is the most abundant divalent cation in the cell and is essential to nearly every biochemical reaction involving adenosine triphosphate (ATP) and its lower energy counterpart, adenosine diphosphate (ADP). In this work, we examine the solution dynamics of ADP at different concentrations and record the changes thereof due to the presence of Mg2+ ions. Relaxation and diffusion experiments were performed on a range of ADP solutions with increasing magnesium concentration. The most significant changes of both relaxation and diffusion behaviors are observed when adding Mg2+ up to 0.5 ADP equivalent (eq), with most of the changes complete at 1 eq. Molecular dynamics simulations also show a significant structure introduced by Mg2+ with very stable pyramidal coordination with the phosphate oxygens. A more extended structure found in the presence of Mg2+ is consistent with the experimental slowing of diffusion and an increase in the spin-lattice relaxation rate. We do not observe direct evidence of aggregation in solution, although translational diffusion is slowed down significantly at higher concentrations (while solvent diffusion remains constant).

Vascular response following implantation of the third-generation drug-eluting resorbable coronary magnesium scaffold: an intravascular imaging analysis of the BIOMAG-I first-in-human study.

BACKGROUND: The 12-month outcomes of BIOMAG-I - the first-in-human study investigating the third-generation drug-eluting resorbable magnesium scaffold (DREAMS 3G) - showed promising results regarding clinical outcomes and late lumen loss. AIMS: The current study aimed to investigate vascular healing parameters assessed by optical coherence tomography (OCT) and intravascular ultrasound (IVUS), focusing on strut visibility, vessel and scaffold areas, and neointimal growth patterns. METHODS: This is a BIOMAG-I substudy including patients with available serial OCT and IVUS data. We conducted a frame-based analysis of OCT findings in conjunction with IVUS-derived vessel and scaffold areas, evaluating the qualitative and quantitative aspects of vascular healing. RESULTS: Among the 116 patients enrolled in this trial, 56 patients treated with DREAMS 3G were included in the analysis. At 12 months, OCT imaging revealed that 99.0% of the struts were invisible, and no malapposed struts were depicted. While the vessel area showed no significant difference between the timepoints, the minimum lumen area significantly decreased from post-percutaneous coronary intervention to 6 months (6.88 mm2 to 4.75 mm2; p<0.0001), but no significant changes were observed between 6 and 12 months. Protruding neointimal tissue (PNT) - a unique neointimal presentation observed following resorbable magnesium scaffold implantation - was observed in 89.3% of the study patients at 12 months, and its area exhibited a 47.4% decrease from 6 to 12 months. CONCLUSIONS: This imaging substudy revealed that, at 12-month follow-up, virtually all struts of the DREAMS 3G scaffold became invisible, without evident malapposition. The vascular healing response to DREAMS 3G implantation also appeared favourable up to 12 months, which is indicated by advanced strut degradation and spontaneous regressing PNT between 6 and 12 months.

Thermal phenomena and size effects of Mg powder in combustion process.

Magnesium is a combustible metal that poses various safety risks, including fires and explosions. However, there are limited safety measures available to prevent and respond to potential fires and explosion incidents in the metal industry. In this study, the combustion process of Mg fires was closely examined using infrared thermal imaging, focusing on the effects of Mg powder size. For the experiment, Mg powder was burned by increasing the temperature to approximately 967.4 K using an ignition unit and controller equipped with a tungsten heater. Moreover, combustion velocity measurement experiments for Mg particle sizes of 75, 100, and 150 µm were conducted using the combustion velocity measurement device presented in the NFPA 484 standard. On combustion of Mg, flames are observed; smoke is emitted as demonstrated by thermal and flow visualization experiments. The combustion velocity measurement experiment results demonstrated that the greater the slope value (combustion velocity) for the combustion length over time, the faster is the combustion velocity, with the 75 µm particle size having the fastest combustion velocity. The results of this experiment can be utilized as references for Mg fire control design and to gain a better understanding of the scope of smoke and fire hazard investigation measures.

Revised version with tracked changes oral Magnesium reduces levels of pathogenic autoantibodies and skin disease in murine lupus.

BACKGROUND: Systemic Lupus Erythematosus (SLE) has a strong genetic susceptibility, but little is known about the impact of diet on disease severity. The Western diet is typically deficient in magnesium (Mg), and given the immunomodulatory effects of Mg, we hypothesized that the low Mg intake increases disease risk and that increasing Mg intake would reduce severity of murine lupus. Here, we placed 12-week old MRL/lpr female lupus mice on a normal (Mg500) or a high (Mg2800) Mg diet for 9 weeks. Urine and blood were collected during the study for quantification of urinary albumin, BUN, anti-dsDNA antibodies, and immune phenotyping. RESULTS: MRL/lpr lupus mice on high Mg2800 diet had significantly fewer skin lesions and less severe skin histology score, and reduced levels of pathogenic anti-dsDNA antibodies, compared with the Mg500 group (143.8±75.0 vs. 47.4±36.2 × 106U/ml; P < 0.05). The high Mg2800 group had a nearly two-fold increase in the percentage of CD4+FOXP3+ Treg cells compared to controls (19.9±5.4 vs. 11.4±5.5%; P < 0.05). Treg percentages inversely correlated with the concentration of anti-dsDNA. None of the mice developed arthritis during the observation period and there were no significant differences in weight, proteinuria, BUN or kidney histology. CONCLUSION: In conclusion, oral supplementation of Mg has a protective effect in a murine lupus model and may represent an inexpensive and safe adjuvant in the treatment of SLsE.

Is there an Association between Dietary Micronutrients Intake and Bone Fractures among Malaysian Reproductive-Age Women? The PURE Malaysia Study.

Background: Bone fractures represent a significant health issue and impose a considerable burden on healthcare systems globally. However, data pertaining to bone fractures, especially among reproductive-age women in Malaysia, are very limited. Micronutrients like calcium, magnesium and phosphorus play vital roles in bone health, influencing bone mineral density and fracture risk. The objective of this study was to determine the prevalence of bone fractures among reproductive-age women and the association with dietary micronutrient intakes. Methods: In this cross-sectional study, a total of 1,730 participants of reproductive-age women from the Malaysia Prospective Urban and Rural Epidemiological (PURE) study were recruited. The participants' dietary intakes were assessed using a validated semi-quantitative food frequency questionnaire (FFQ). Selected micronutrients in the participants' diets were calculated using the Malaysian food composition and the US Department of Agriculture food composition databases. The association between micronutrient intakes, comorbidities and physical activity levels with bone fractures were evaluated to identify predictors of bone fractures among reproductive-age women. Results: The prevalence of bone fractures among Malaysian reproductive-age women was low (3.7%). The multiple logistic regression analysis showed that none of the micronutrients was associated with bone fractures. However, factors of diabetes and passive smoking in this study showed 2.6- and 4.0-times-higher odds of having bone fractures, respectively (AOR 2.580; 95% CI: 1.173-5.672) and (AOR 4.012; 95% CI: 2.265-7.107). Conclusions: It was found that the majority of women in this study were taking lower micronutrient intakes of calcium, magnesium, and vitamin K than the Malaysia recommended nutrient intakes (RNI). Although this study showed that a low micronutrient intake is not significantly associated with bone fractures, it is recommended that future studies focus on controlled trials or prospective data analyses to establish causal relationships and the optimal micronutrient requirements for maintaining strong and healthy bones in women of reproductive age.

Iron: Life's primeval transition metal.

Modern life requires many different metal ions, which enable diverse biochemical functions. It is commonly assumed that metal ions' environmental availabilities controlled the evolution of early life. We argue that evolution can only explore the chemistry that life encounters, and fortuitous chemical interactions between metal ions and biological compounds can only be selected for if they first occur sufficiently frequently. We calculated maximal transition metal ion concentrations in the ancient ocean, determining that the amounts of biologically important transition metal ions were orders of magnitude lower than ferrous iron. Under such conditions, primitive bioligands would predominantly interact with Fe(II). While interactions with other metals in certain environments may have provided evolutionary opportunities, the biochemical capacities of Fe(II), Fe-S clusters, or the plentiful magnesium and calcium could have satisfied all functions needed by early life. Primitive organisms could have used Fe(II) exclusively for their transition metal ion requirements.

Hypomagnesaemia leading to parathyroid dysfunction, hypocalcaemia, and hypokalaemia as a complication of long-term treatment with a proton pump inhibitor - a literature review.

Proton pump inhibitors (PPIs) are one of the most frequently used medications worldwide. The side effects of this class of drugs have been widely studied. However, their impact on the electrolyte balance is frequently forgotten. Long-term PPI administration can lead to profound electrolyte disturbances, namely hypomagnesaemia as well as, secondary to very low magnesium levels, hypocalcaemia and hypokalaemia. In this paper we comprehensively review the complexity of the mechanisms contributing to electrolyte imbalance following PPI (proton pump inhibitors) by changing the pH in the intestinal lumen, interfering with the active cellular transport of magnesium regulated by the transient receptor potential melastatin cation channels TRPM6 and TRPM7. The accompanying hypomagnesaemia causes unblocking of the renal outer medullary potassium channel (ROMK), which results in increased potassium loss in the ascending limb of the loop of Henle. Hypokalaemia caused by hypomagnesaemia is resistant to potassium supplementation because the loss of this element in urine increases with the supply of potassium. Additionally, within the calcium-sensitive receptor (CASR), dissociation of magnesium from the alpha subunit of G protein caused by hypomagnesaemia increases its activity, leading to inhibition of PTH secretion and hypocalcaemia resistant to calcium supplementation. All this means that in some patients, chronic use of proton pump inhibitors by affecting the absorption of magnesium, may lead to life-threatening electrolyte disorders.

Maintenance of magnesium homeostasis by NUF2 promotes protein synthesis and anaplastic thyroid cancer progression.

Thyroid cancer is the most frequently observed endocrine-related malignancy among which anaplastic thyroid cancer (ATC) is the most fatal subtype. The synthesis of protein is active to satisfy the rapid growth of ATC tumor, but the mechanisms regulating protein synthesis are still unknown. Our research revealed that kinetochore protein NUF2 played an essential role in protein synthesis and drove the progression of ATC. The prognosis of patients with thyroid carcinoma was positively correlated with high NUF2 expression. Depletion of NUF2 in ATC cells notably inhibited the proliferation and induced apoptosis, while overexpression of NUF2 facilitated ATC cell viability and colony formation. Deletion of NUF2 significantly suppressed the growth and metastasis of ATC in vivo. Notably, knockdown of NUF2 epigenetically inhibited the expression of magnesium transporters through reducing the abundance of H3K4me3 at promoters, thereby reduced intracellular Mg2+ concentration. Furthermore, we found the deletion of NUF2 or magnesium transporters significantly inhibited the protein synthesis mediated by the PI3K/Akt/mTOR pathway. In conclusion, NUF2 functions as an emerging regulator for protein synthesis by maintaining the homeostasis of intracellular Mg2+, which finally drives ATC progression.

Intravenous Magnesium for the Management of Chronic Pain:An Updated Review of the Literature.

Background: Available therapeutic options are currently limited by their modest efficacy. As a result, novel pharmacotherapeutic treatments with different mechanisms have recently attracted empirical attention. Magnesium, a divalent cation, is postulated to provide analgesic and anti-nociceptive effect through its action at the N-methyl-D-aspartate (NMDA) receptor. Objective: Considering the evidence surrounding magnesium's potential as a therapeutic modality for chronic pain, we conducted a narrative review on the evidence of magnesium's therapeutic effects in chronic pain. Methods: A review of the PubMed, and Google scholar databases was undertaken in May 2022 to identify completed studies that investigated the effectiveness of magnesium in the treatment of chronic pain from database inception to May 2022. Results: A total of 33 studies were included in the narrative review, out of which 26 were randomized controlled trials. Findings on available studies suggest that intravenous infusion of magnesium is an emerging and promising option that may alleviate pain in some clinical populations. Our narrative synthesis showed that evidence for intravenous magnesium is currently equivocal for a variety of chronic pain syndrome. Findings indicate that evidence for efficacy is poor or equivocal for: CRPS, neuropathic pain, chronic low back pain, and migraine prophylaxis. However, there is good evidence supporting the efficacy of intravenous magnesium for treating renal colic pain and pelvic pain related to endometriosis. Conclusion: Magnesium may be a promising pharmacologic solution for chronic pain. Future investigation is warranted on elucidating the neurobiological mechanisms of magnesium in attenuating pain signaling pathways.

A portable lateral flow distance-based paper sensor for drinking water hardness test.

Hardness is one of the basic parameters of water, and a high-level hardness of drinking water may be harmful to human health. Thus, it is very important to monitor drinking water hardness. In this work, a portable lateral flow distance-based paper sensor for the semi-quantitative detection of drinking water hardness is demonstrated. In the presence of Ca2+/Mg2+, the hydrogel can be formed via the chelation between sodium alginate and Ca2+/Mg2+, inducing a phase separation process. The viscosity change of the sodium alginate solution is directly related to the Ca2+/Mg2+ concentration and can be determined by the water lateral flow distance on test strips. The sensor successfully realizes the quantification of Ca2+ and Mg2+ in the range of 0-10 mmol L-1 and 4-20 mmol L-1, respectively. The recoveries are found varied from 95% to 108.9%. The water hardness is acceptable for drinking if the Cr values lies in the range of 0.259 to 0.419, and it is high with the Cr value above 0.595. Remarkably, the performance of the sensor is comparable with the commercial kit for real water samples, which avoids the subjective judgment. Overall, this method provides a portable approach for semi-quantitative detection of drinking water hardness with the merits of convenience and low cost, which shows great potential for the potential application.