Melamine

Food Chem. 2025 Dec 28;503:147778. doi: 10.1016/j.foodchem.2025.147778. Online ahead of print.

ABSTRACT

Herein, we constructed a SERS sensing platform based on a core-shell material, AuNRs@ZnO-Ov, for the detection of melamine in milk. The high Raman signal intensity can be attributed to the synergistic effect between the electromagnetic enhancement and chemical enhancement. The FDTD and molecular energy level calculations have verified the amplification of the electromagnetic field and the process of charge transfer. The AuNRs@ZnO-Ov exhibited high SERS performance with an enhancement factor (EF) of 7.08 × 10⁶, and a limit of detection (LOD) of 4.06 × 10^-8 M for melamine with good uniformity and reproducibility. Furthermore, the SERS platform delivered good linearity across a wide concentration range of 5 × 10^-8 to 5 × 10^-4 M. The proposed method has been successfully used for the detection of melamine in milk samples. This study provides a potential strategy for the construction of novel SERS substrates for molecules sensing in food.

PMID:41475260 | DOI:10.1016/j.foodchem.2025.147778

Foods. 2025 Dec 13;14(24):4292. doi: 10.3390/foods14244292.

ABSTRACT

The aim of this study is to investigate the occurrence of melamine and cyanuric acid in milk, baby food, and protein supplements collected in Croatia. A total of 56 samples were collected during 2022 and 2023 from retail stores in Zagreb, Croatia. Sample preparation involved acetonitrile extraction, followed by analysis using ultra-high-performance liquid chromatography coupled with tandem mass spectrometry (UHPLC-MS/MS). Cyanuric acid concentrations above the limit of quantification (LOQ) were found in five milk samples (33.3% detection frequency), with a range from 0.26 to 0.39 mg/kg and a mean concentration of 0.31 mg/kg. In protein supplements, melamine was detected above the LOQ in six samples (23% detection frequency), with a mean concentration of 0.30 mg/kg and concentrations ranging from 0.20 to 0.57 mg/kg. No concentrations above the LOQ were found in baby food samples. All detected values were below the EU maximum limits (2.5 mg/kg for general food and 1.0 mg/kg for baby food). The accuracy and reliability of the method were verified using certified reference material. This is the first study to confirm the presence of melamine and cyanuric acid in protein supplements and milk on the Croatian market. The detected levels do not indicate a potential health risk to consumers.

PMID:41464998 | PMC:PMC12732134 | DOI:10.3390/foods14244292

Alzheimers Dement. 2025 Dec;21 Suppl 1(Suppl 1):e102250. doi: 10.1002/alz70855_102250.

ABSTRACT

BACKGROUND: Several findings have highlighted the importance of diet and ecotoxic compounds on aging. Melamine (Mel), a widely documented food adulterant, has demonstrated toxicity in multiple organs of the human body, including the brain. However, its neurotoxic effects on aging neurons remain unexplored. This study aims to bridge this gap by investigating the in-vitro neurotoxic impact of Mel in a D-galactose (DG)-induced aging model of neuronal SH-SY5Y cells.

METHOD: In the present study, the SH-SY5Y cells were administered a toxic dose of Mel and DG individually and in combination (Mel + DG) to determine their potential for neurotoxicity. The analysis involved measuring cell viability through MTT assay and morphological examination via neurite length assessment. Furthermore, we evaluated the antioxidant status of the cells by examining catalase (CAT), superoxide dismutase (SOD), and total antioxidant activities. Subsequent investigations of reactive oxygen species (ROS), mitochondrial membrane potential (MMP), and caspase-3 (Casp3) activity were also performed.

RESULT: The co-administration with Mel and DG resulted in the highest cell death compared to individual treatments of Mel or DG and control untreated cells. The combined exposure of Mel and DG also led to significant neurite shrinkage and ROS accumulation, indicating exacerbated toxicity. Moreover, SOD, CAT, and total antioxidant levels were significantly reduced in the co-treatment (Mel + DG) group than in Mel-only or DG-only treated group, showing excessively hampered antioxidant state. Additionally, the Casp3 activity was markedly elevated in the cell group jointly treated with Mel and DG, as compared to Mel or DG alone treated groups, signifying a heightened apoptotic reaction.

CONCLUSION: This study provides early insights into the increased neurotoxic potential of Melamine (Mel) in an aging model of neuronal cells. The outcomes reveal that Mel consumption in the elderly may contribute to a higher risk of neurodegenerative disorders, such as Alzheimer's and Parkinson's diseases.

PMID:41436745 | PMC:PMC12727672 | DOI:10.1002/alz70855_102250

Neurotox Res. 2025 Dec 16;43(6):53. doi: 10.1007/s12640-025-00773-z.

ABSTRACT

Melamine, an industrial chemical linked to neurotoxicity, prompted this study investigating taurine's neuroprotective effects in rat brains. The study examined the impact of taurine on brain metabolic enzymes, neurochemicals, autophagy-related proteins, and oxidative-inflammatory pathways. Twenty-eight rats were divided into four groups (seven rats per group): control (saline), taurine (100 mg/kg), melamine (50 mg/kg/day), and melamine plus taurine. Taurine administration (30 min post-melamine) continued daily for 28 days, starting on day 29 to day 56, which allowed for the assessment of its restorative effect against ongoing melamine-induced neurotoxicity. Non-spatial recognition memory was evaluated using the novel-object recognition memory test (NORT). Following this, brain neurochemical status, metabolic enzymes, autophagic proteins, and oxidative-inflammatory markers were assessed postmortem. Results demonstrated that taurine improved cognitive function in melamine-treated rats, as evidenced by increased exploration of novel objects in the NORT. Taurine protected against melamine-induced oxidative stress. Additionally, taurine reduce tumor necrosis factor-alpha (TNF-α), interleukin (IL)-6, and IL-1β expression, modulated mammalian target of rapamycin (mTOR) and beclin-1, restored brain metabolic enzyme activity, enhanced neurotransmitter levels, and prevented alterations in α-synuclein and paraoxonase 1 (PON1). In conclusion, taurine protects against melamine-induced neurotoxicity in rats by improving autophagic response, downregulating apoptosis and inflammation markers, inhibiting oxidative stress, and potentially restoring brain metabolic enzyme activities and neurotransmitter levels.

PMID:41398135 | DOI:10.1007/s12640-025-00773-z

Environ Res. 2026 Feb 1;290:123493. doi: 10.1016/j.envres.2025.123493. Epub 2025 Dec 3.

ABSTRACT

Global aquaculture is expanding rapidly, but the improper discharge of tetracycline (TC) in effluent water has triggered an increase in bacterial resistance, posing a threat to aquatic ecosystems and human health. Traditional graphitic carbon nitride (g-C₃N₄) has limitations like fast photogenerated charge recombination and small specific surface area, restricting its application. This study synthesized Ca-doped (g-C₃N₄) (CaCN) via a CaCl₂-modified melamine molten-salt method, then prepared kaolin/CaCN-x composites by calcining calcined kaolin and CaCN (mass ratios x = 1, 0.5, 0.25, 0.17) at 500 °C for 330 min. Materials were characterized by XRD, SEM/EDX, BET, UV-Vis DRS, and XPS. Photocatalytic tests evaluated effects of catalyst dosage, TC concentration, pH, humic acid, and temperature on 20 mg/L TC (pH 7 ± 0.2) degradation. Radical quenching, LC-MS, and toxicity assays (using Microcystis aeruginosa, monitoring algal density and chlorophyll a) clarified active species, degradation pathways, and product toxicity; real water and cycling tests verified application potential. Kaolin/CaCN-0.25 showed optimal performance: 98.7 % TC removal, degradation rate constant 0.03185 min^-1 (3.36 × that of pure g-C₃N₄), specific surface area 77.573 m²/g, and bandgap 2.68 eV ·O₂^- and ·OH dominated TC degradation via two pathways; product toxicity decreased after 60 min. The composite removed >97 % TC in real water, retained 90 % efficiency after 3 cycles, and maintained structural stability. This work provides a low-cost in-situ photocatalytic technology, offering material and theoretical support for TC remediation in aquaculture tailwater.

PMID:41349662 | DOI:10.1016/j.envres.2025.123493

J Dairy Sci. 2025 Dec 3:S0022-0302(25)00994-4. doi: 10.3168/jds.2025-27071. Online ahead of print.

ABSTRACT

The focus of study was to investigate physicochemical, microbiological, and quality characteristics of raw standardized milk collected from different northern parts of India. Results showed that physicochemical test values for pH, acidity, moisture, fat, SNF, total soluble solids, protein were varied from 6.62 to 6.66, 0.133% to 0.121%, 84.17% to 86.01%, 5.09% to 6.59%, 8.47% to 9.23%, 13.56% to 15.82%, 36.45% to 36.78%, and 0.61% to 0.73%, respectively. These results were in accordance with Codex International Standard and the Food Safety and Standards Authority of India. The Reichert-Meissl value, Butyro-refractometer reading, and sodium content of raw standardized milk varied from 28.76 to 29.36, 41.31 to 41.63, and 432 to 597, respectively. Various adulterants tests were performed for different milk samples; negative results were obtained for all but 2 samples, which had adulterants such as sugar, skim milk, and antibiotic residues. The results of melamine and aflatoxin M₁ of standardized milk varied between 58.17 and 90.83 and 0.17 and 1.26, respectively. Microbiological analysis showed that in 6 samples of standardized milk, the aerobic plate count and SCC were found to be crossed the upper limit (i.e., 10 × 10⁵ and 25 × 10⁴, respectively). Two samples of standardized milk contained higher MA, TS, and psychotropic count as compared with world standards. The sensory scores for all but 3 standardized milk samples varied from 6 to 8. This study helps to analyze the quality of milk, which is being tainted with various adulterants because of a lack of supervision, unsanitary facilities, or for financial gain.

PMID:41349831 | DOI:10.3168/jds.2025-27071

Mater Des. 2025 Nov;259:114910. doi: 10.1016/j.matdes.2025.114910. Epub 2025 Oct 13.

ABSTRACT

Approximately 50% of resin-based dental restorations fail within ten years, mainly due to secondary caries and material fractures. Incorporating self-healing microcapsules containing resin-based agents that polymerize upon release offers a promising strategy to repair microcracks and extend restoration longevity. Poly(urea-formaldehyde) (PUF) microcapsules are commonly used, but formaldehyde cytotoxicity remains a concern. This study developed alternative microcapsules by integrating melamine into the polymeric shell (PUMF) and functionalizing surfaces with methacrylate (TMSPM) or thiol (MPTMS) silanes, with or without a TEOS pre-coating, to reduce formaldehyde release and enhance biocompatibility. Microcapsules were synthesized via double-emulsion, encapsulating triethylene glycol dimethacrylate (TEGDMA), and characterized for morphology, mechanical stability, functionalization efficiency, formaldehyde release, and cytotoxicity. Melamine increased mechanical and morphological stability, surface roughness, and core retention, especially under functionalization, but also raised formaldehyde release in unmodified capsules. Functionalization with TMSPM and MPTMS significantly reduced formaldehyde release from both PUF and PUMF capsules. Metabolic assays showed dental pulp stem cells were more sensitive to TEGDMA, while fibroblasts were affected by TEGDMA combined with prolonged formaldehyde exposure. Overall, melamine-reinforced functionalized microcapsules exhibit improved stability, controlled formaldehyde release, and enhanced biocompatibility, supporting their potential as next-generation self-healing dental materials.

PMID:41311641 | PMC:PMC12652498 | DOI:10.1016/j.matdes.2025.114910

Toxics. 2025 Nov 4;13(11):950. doi: 10.3390/toxics13110950.

ABSTRACT

With the widespread use of emerging contaminants such as melamine (MEL) and organophosphate esters (OPEs) as alternatives to traditional flame retardants, their ubiquitous presence in the environment has raised concerns about human internal exposure and health risks. Urine, as a critical matrix for biomonitoring, enables accurate assessment of internal exposure to these contaminants and their metabolites. This review systematically summarizes the research progress on urinary biomonitoring of MEL and its derivatives (cyanuric acid (CYA), ammeline (AMN), ammelide (AMD)) and OPE metabolites. It covers analytical methods (sample pretreatment including enzymatic hydrolysis and extraction, instrumental detection via HPLC-MS/MS/UPLC-MS/MS, and method validation), exposure characteristics (global spatial differences, population disparities among sensitive groups like children and e-waste workers, and temporal variations such as postprandial peaks), and health risk assessments. Results show that MEL and CYA are widely detected in urine (detection rates > 97%), with CYA dominating total MEL (66.2-80%); OPE metabolites exhibit regional compositional differences, e.g., bis(2-chloroethyl) phosphate (BCEP) in Shenzhen and diphenyl phosphate (DPHP) in New York. Current exposure levels are generally safe, but 2-12% of sensitive individuals face potential risks. This review highlights key challenges (method standardization, limited hydroxylated OPE standards) and provides directions for future research to establish a comprehensive exposure-health risk evaluation system.

PMID:41304502 | PMC:PMC12656575 | DOI:10.3390/toxics13110950

Biosensors (Basel). 2025 Nov 11;15(11):754. doi: 10.3390/bios15110754.

ABSTRACT

Nanotechnology offers powerful new tools to enhance food quality monitoring and safety assurance. In the food industry, nanoscale materials (e.g., metal, metal oxide, carbon, and polymeric nanomaterials) are being integrated into sensory systems to detect spoilage, contamination, and intentional food tampering with unprecedented sensitivity. Nanosensors can rapidly identify foodborne pathogens, toxins, and chemical changes that signal spoilage, overcoming the limitations of conventional assays that are often slow, costly, or require expert operation. These advances translate into improved food safety and extended shelf-life by allowing early intervention (for example, via antimicrobial nano-coatings) to prevent spoilage. This review provides a comprehensive overview of the types of nanomaterials used in food sensory applications and their mechanisms of action. We examine current applications in detecting food spoilage indicators and adulterants, as well as recent innovations in smart packaging and continuous freshness monitoring. The advantages of nanomaterials-including heightened analytical sensitivity, specificity, and the ability to combine sensing with active preservative functions-are highlighted alongside important toxicological and regulatory considerations. Overall, nanomaterials are driving the development of smarter food packaging and sensor systems that promise safer foods, reduced waste, and empowered consumers. However, realizing this potential will require addressing safety concerns and establishing clear regulations to ensure responsible deployment of nano-enabled food sensing technologies. Representative figures of merit include Au/AgNP melamine tests with LOD 0.04-0.07 mg L^-1 and minute-scale readout, a smartphone Au@carbon-QD assay with LOD 3.6 nM, Fe₃O₄/DPV detection of Sudan I at 0.001 µM (linear 0.01-20 µM), and a reusable Au-Fe₃O₄ piezo-electrochemical immunosensor for aflatoxin B1 with LOD 0.07 ng mL^-1 (≈15 × reuse), alongside freshness labels that track TVB-N/amine in near-real time and e-nose arrays distinguishing spoilage stages.

PMID:41294764 | PMC:PMC12650047 | DOI:10.3390/bios15110754

Food Res Int. 2025 Dec;222(Pt 1):117513. doi: 10.1016/j.foodres.2025.117513. Epub 2025 Sep 18.

ABSTRACT

This study aimed to evaluate the levels of inorganic contaminants -lead (Pb), cadmium (Cd), mercury (Hg), and arsenic (As)-as well as melamine in animal-derived milk (ADM) and plant-based milk alternatives (PBMAs) available on the Turkish market. A total of 54 milk samples, representing 12 brands, were collected from four supermarkets in Ankara in June 2023. Contaminant levels were quantified using inductively coupled plasma mass spectrometry (ICP-MS). Melamine was detected in the majority of samples, with only two PBMAs-coconut-based and soy-based-exceeding 50 μg/kg. All PBMA and ADM samples were below the European Union (EU) limit for Pb (20 μg/kg), although one cow milk sample surpassed 10 μg/kg. Cd concentrations above 10 μg/kg were found in 10.3 % of cow milk samples, particularly in ultra-high-temperature (UHT) processed products. Hg was undetectable in four samples and remained below 5 μg/kg in all others. As levels were consistently below 10 μg/kg. Hg and As levels varied significantly by processing method, while Pb and As levels differed depending on the type of packaging. No significant correlation was observed between protein or fat content and contaminant concentrations. Health risk assessments conducted for 6-year-old children indicated that both daily dietary intake (DDI) and hazard quotient (HQ) values for all toxic elements and melamine were below the threshold of 1, suggesting no significant non-carcinogenic risk. Overall, the findings indicate that both milks are chemically safe for young children. However, continued monitoring is recommended, particularly for melamine and arsenic, due to their potential for cumulative toxicity.

PMID:41267225 | DOI:10.1016/j.foodres.2025.117513

Environ Sci Process Impacts. 2025 Nov 20. doi: 10.1039/d5em00516g. Online ahead of print.

ABSTRACT

Globally, recycling of otherwise waste materials into new products is desired. End-of-life tyres are increasingly incorporated into new pavement materials but leaching of entrained chemicals from such products is not well quantified. Chemical concentrations in runoff from pavements may pose environmental and human health risks. High liquid-solid ratio, batch-agitated leaching is standard practice for assessing leachability and hazards of chemicals-of-potential-concern in contaminated soil and wastes but is not reflective of important exposure scenarios and may mislead. A new static surface leaching procedure (SSLP) is introduced that is more representative of chemical leaching from pavement reuse materials whilst in contact with rainfall/runoff water. SSLP was evaluated over 2-14 d intervals against batch-agitated leaching for two rubberised pavement products containing 10-fold different proportions of crumbed end-of-life tyres. Although, batch leaching showed high mass removal of 1,3-diphenylguanidine (1,3-DPG, 34%) and hexamethoxymethylmelamine (HMMM, 30%), both batch- and SSLP-leached concentrations of 1,3-DPG, HMMM and N¹-(4-methylpentan-2-yl)-N⁴-phenylbenzene-1,4-diamine quinone (6PPD-Q) were below ECOSAR-predicted toxicity thresholds for fish and daphnids. SSLP highlighted differences in chemical leachability based on rubber content of pavement products and offers a method applicable to other scenarios, such as PFAS leaching from concrete/asphalt pavements. The SSLP was shown to approximate one-dimensional leaching from the surface of the pavement and to be dominated by diffusive processes, thus yielding a simple repeatable approach.

PMID:41263588 | DOI:10.1039/d5em00516g

J Colloid Interface Sci. 2026 Feb 15;704(Pt 2):139454. doi: 10.1016/j.jcis.2025.139454. Epub 2025 Nov 10.

ABSTRACT

Over the past decades, self-healing poly(urea-formaldehyde) (PUF) microcapsules have been extensively utilized across diverse fields, including textiles, construction, aerospace, and biomedical systems. However, concerns remain regarding their mechanical stability and potential formaldehyde toxicity. Here, we investigate the incorporation of melamine and the high-toughness acrylamide monomer N,N-Dimethylacrylamide (DMAM) to enhance the thermomechanical stability and cytocompatibility of PUF microcapsules containing either triethylene glycol dimethacrylate (TEGDMA) or a TEGDMA-DMAM blend at 20 wt%. Melamine was incorporated into the shell precursor up to 10 wt%, and the resulting microcapsules were characterized for morphology, mechanical, thermal, and biological properties. In general, melamine increased shell roughness and physicochemical stability, with 5 wt% providing the best balance. DMAM improved shell elasticity, and the combined use of DMAM and melamine yielded the highest elasticity (57 %). Formaldehyde release, quantified via a Purpald assay, increased with melamine content (up to 21 μM after one week), yet dental pulp stem cell (DPSC) viability remained ≥95 % across all tested concentrations. Direct exposure to microcapsules maintained DPSC viability above 85 % for all formulations. Healing efficiency was ≥82 % in all tested materials, with DMAM-containing systems showing a ∼ 20 % improvement compared to TEGDMA-only formulations. These results demonstrate that melamine and DMAM enhance microcapsule durability while preserving cytocompatibility, supporting their potential use in biomedical applications such as self-healing dental composites.

PMID:41232250 | PMC:PMC12622392 | DOI:10.1016/j.jcis.2025.139454

Water Res. 2026 Jan 15;289(Pt A):124867. doi: 10.1016/j.watres.2025.124867. Epub 2025 Oct 28.

ABSTRACT

Organic contaminants and dissolved organic matter (DOM) inevitably coexist and are exposed to sunlight in the aquatic environments, underscoring their interrelated roles in degradation processes. Hexa(methoxymethyl)melamine (HMMM), a widely used tire additive, has been frequently detected in aquatic environmental media, and exhibits a chemical structure that suggests potential ecological risks. DOM significantly influences the contaminant fate by acting as a photosensitizer and by generating reactive species. Photolysis is an essential environmental transformation pathway affecting both HMMM and DOM. In this study, HMMM and DOM were studied as an integrated system to investigate their UV-induced photolysis behavior, identify key degradation factors, and assess the toxicity of transformation products. Results demonstrate that both DOM and HMMM undergo transformation during photolysis. Notably, DOM generally inhibits the photodegradation of HMMM, while simultaneously facilitates a reductive degradation pathway initiated by reactive reducing species (RRS, including ³DOM* and e_aq^-). Our findings comprehensively provide evidence for RRS generation, supported by direct detection via electron capture signals and indirect indicators such as photolysis kinetics within HMMM-DOM system. These results refine the current understanding of photolysis pathways for tire-related contaminants in aquatic environments and emphasize the importance of evaluating contaminants and DOM as an integrated system in environmental photochemistry.

PMID:41176979 | DOI:10.1016/j.watres.2025.124867

Sci Rep. 2025 Oct 30;15(1):37930. doi: 10.1038/s41598-025-22712-w.

ABSTRACT

Green analytical chemistry is an innovative approach to making analytical experiments more environmentally friendly, safer for humans, and less toxic to the environment by utilizing eco-friendly reagents and chemicals. Diabetics are twice as likely to experience hypertension compared to nondiabetics. Individuals with both conditions face a significantly increased risk of early microvascular and macrovascular complications. Regular monitoring helps ensure the drug concentration remains within the therapeutic range, maximizing its effectiveness. Herein, a high-performance liquid chromatographic (HPLC) method is provided to evaluate and isolate the studied drugs in the presence of their toxic impurities. The study involves the simultaneous administration of two crucial drugs: the antidiabetic metformin and the antihypertensive bisoprolol. We have investigated their pure form in spiked human plasma, as well as their interaction while their possible toxic impurities are present as melamine and cyanoguanidine. The optimal conditions were achieved using a mobile phase consisting of 0.1 M SDS, 0.1% ortho-phosphoric acid in water, and 10% isopropanol at a flow rate of 1.0 mL/min. The pH was adjusted to 5.0 using triethylamine, and the column temperature was maintained at 25 °C on a symmetry C18 column (Kinetex 1.7µ C18 100A, 2.1-mm × 50-mm), with detection at 230 nm. Following the International Conference of Harmonization guideline, the method was successfully validated within the linearity range of 1-25 µg/mL for metformin and bisoprolol. Notably, the LOQ was determined to be 0.92 µg/mL for metformin and 0.54 µg/mL for bisoprolol. The established method epitomizes accuracy, cost-effectiveness, selectivity, and reproducibility. The evaluation of the suggested approaches' level of greenness was meticulously conducted using a variety of assessments, including the Analytical eco-scale system, the Modified Green Analytical Procedure Index (MoGAPI), The Analytical Green Star Area (AGSA), Blueness evaluation using BAGI tools, Carbon footprint (CaFRI), Click Analytical Chemistry Index (CACI) and White analytical chemistry (WAC).

PMID:41168405 | PMC:PMC12575862 | DOI:10.1038/s41598-025-22712-w

Arch Microbiol. 2025 Oct 18;207(12):320. doi: 10.1007/s00203-025-04525-7.

ABSTRACT

Melamine is a nitrogen rich compound belonging to the triazine family. The excessive use of melamine is one of the major concerns due to its ability to cause nephrotoxicity, and acute, and chronic kidney disease. In the present study, two fungal strains namely Penicillium hetheringtonii AJ6 and Fusarium sp. MDF3 was isolated using the enrichment technique. These strains were screened for their melamine tolerance ability and could tolerate up to 20 mg/L (P. hetheringtonii), and 29 mg/L (Fusarium sp.) of the contaminant. The degradation studied in an aqueous medium proved that Penicillium hetheringtonii and Fusarium sp. could degrade 78% (initial substrate concentration, 14 mg/L; final substrate concentration, 3.08 ± 0.20 mg/L), and 32% (initial substrate concentration, 20 mg/L; final substrate concentration, 13.6 ± 1.78 mg/L) of introduced melamine respectively. The strains degraded melamine into 2-Propen-1-ol, and 5-methyl-2-hexanone. The degradation kinetics study showed that strains followed zero-order model (P. hetheringtonii), and pseudo second-order model (Fusarium sp.) of kinetics. The significance of kinetic models was assessed using p-value which was reported as 0.007 (zero-order model) and 0.005 (pseudo second-order model). The extracellular enzyme studies revealed that the laccase enzyme system could be responsible for the degradation of melamine. Therefore, the study suggests that the strain P. hetheringtonii AJ6 can be used for melamine remediation from contaminated surfaces.

PMID:41108415 | DOI:10.1007/s00203-025-04525-7

J Appl Toxicol. 2025 Oct 11. doi: 10.1002/jat.4953. Online ahead of print.

ABSTRACT

Graphene oxide (GO) and carbon nanotube (CNT)-based nanomaterials have attracted significant interest in various industrial and biomedical applications due to their unique physicochemical properties; however, concerns about their potential toxicity, especially when modified with additives like melamine (M), remain largely unresolved. This study investigates the toxicological effects and underlying mechanisms of graphene oxide-melamine (GO-M) and carbon nanotube-melamine (CNT-M) nanoparticles in zebrafish (Danio rerio) embryos and larvae. To this end, developmental toxicity, phenotypic and behavioral changes, as well as histopathological and immunofluorescence alterations, were evaluated following acute exposure to GO-M and CNT-M nanoparticles at concentrations of 5, 10, and 20 mg/L. Results showed that both nanoparticles delayed larval hatching, particularly at higher concentrations (10 and 20 mg/L). Malformations were observed at 20 mg/L in the GO-M group and at 10 and 20 mg/L in the CNT-M group. Additionally, significant changes in larval length and eye area were observed at all concentrations for both nanoparticles. Behavioral assessments revealed that CNT-M exposure at 10 and 20 mg/L significantly impaired head sensorimotor reflexes, while all concentrations affected tail reflexes. In contrast, GO-M exposure did not significantly alter sensorimotor responses. These findings suggest differential toxic mechanisms and neurobehavioral effects of GO-M and CNT-M nanoparticles during early zebrafish development.

PMID:41074713 | DOI:10.1002/jat.4953

Food Chem Toxicol. 2026 Jan;207:115773. doi: 10.1016/j.fct.2025.115773. Epub 2025 Sep 30.

ABSTRACT

Exclusive Enteral Nutrition (EEN) can induce remission in Crohn's disease (CD). We completed a pilot study using novel reverse-engineered EEN (RE-EEN), a whole food smoothie in place of commercial liquid formula (EEN) which contains food additives to improve shelf stability and palatability. In a four week trial with RE-EEN, we reported 80 % of patients went into clinical remission after four weeks. We hypothesized RE-EEN would decrease environmental toxin exposure through reduction of processing food intake. Biosamples were collected at baseline and at weeks two, four, and eight during the RE-EEN study. Urinary heavy metals were analyzed by inductively coupled plasma mass spectrometry, and urinary phthalate metabolites and melamine by liquid chromatography with tandem mass spectrometry. For our primary analysis, change in baseline was calculated using a paired t-test for week four. Analysis was also completed for all weeks on RE-EEN using a generalized least squares model. Results were expressed as fold change ± standard error mean. Paired t-testing demonstrated a statistically significant (p < 0.05) effect on molybdenum (Mo) with a fold change of 0.17 ± 0.15, an 83 % reduction following RE-EEN treatment. Our results suggested an effect of arsenic (As) with fold change of 0.23 ± 0.26 (p = 0.12), a 77 % reduction following RE-EEN treatment. Our results also suggested an effect of cobalt (Co) with a fold change of 3.12 ± 3.12 fold, a 212 % increase following RE-EEN therapy (p = 0.16). With inclusion of all weeks on RE-EEN, Mo and As were statistically significant (p < 0.05). Overall, we observed favorable shifts in urinary heavy metals by week four, and no effects were suggested in phthalate and melamine analysis. We saw increased precision in a sensitivity analysis when including all weeks for treatment. This is the first study to examine environmental toxicants in relation to whole foods smoothie diet in pediatric CD. RE-EEN dietary intervention shows promise in reducing chemical exposures and may contribute to CD remission. Notable limitations to this research include small sample size and absence of a control group. Further studies are necessary to assess the impact of RE-EEN diet on environmental toxicant exposure.

PMID:41038373 | PMC:PMC12640686 | DOI:10.1016/j.fct.2025.115773

J Hazard Mater. 2025 Sep 16;498:139914. doi: 10.1016/j.jhazmat.2025.139914. Online ahead of print.

ABSTRACT

Landfill leachate (LFL) typically contains a wide range of potential pollutants, making it difficult to treat and inefficient in resource utilization. This work developed a new multifunctional evaporator that integrated photothermal evaporation with photocatalytic degradation to enable in situ purification and water recovery. The device was fabricated by immobilizing a hydrothermally synthesized Nickel Oxide- Titanium Dioxide- Carbon Nanotube (NiO-TiO₂-CNT) composite on a melamine sponge via sodium alginate crosslinking, forming a synergistic evaporation-degradation interface. Under 1 kW·m⁻² solar irradiation, the system achieved an evaporation rate of 2.25 kg·m⁻²·h⁻¹ , where the addition of 1 mmol·L⁻¹ PMS boosted phenol removal efficiency to 90 %. When applied to real LFL, COD was reduced from 4266 to 53 mg·L⁻¹ , and phosphate was completely removed to below detection limits (<0.01 mg·L⁻¹). Although ammoniacal nitrogen levels remained relatively high at 354 mg·L⁻¹ , post treatment phytotoxicity tests involving irrigation of wheat with leachate resulted in a 90 % germination rate, which increased to 100 % after dilution. This indicated the treated leachate was safe and could potentially be used as a nitrogen-rich liquid fertilizer. A techno-economic analysis showed that the system could be operated at a cost of only 10.33 USD per metric ton, significantly lower than conventional treatments. This work thus provides a cost-effective sustainable strategy for simultaneous pollutant control, water reuse, and ecological restoration of landfill sites.

PMID:40974682 | DOI:10.1016/j.jhazmat.2025.139914

Talanta. 2026 Feb 1;298(Pt A):128832. doi: 10.1016/j.talanta.2025.128832. Epub 2025 Sep 11.

ABSTRACT

Surface-enhanced Raman scattering (SERS) based on noble metal nanoparticles has garnered significant attention in analytical chemistry due to its simplicity and rapidity for low-concentration detection. Although widely applied in fields such as environmental monitoring, food safety, and biomedical diagnostics, the impact of silver nanoparticle shape on SERS performance remains insufficiently studied. Furthermore, traditional stationary solid and liquid SERS approaches are limited by inconsistent reproducibility and temporal variations in uniformity, respectively. To overcome these limitations, we introduce a simple continuous and online Ag SERS platform that employs spherical silver colloids within a capillary-Teflon tube system for dynamic, real-time analyte detection. Continuous fluid flow reduces variations in colloids, ensuring uniformity, while the enclosed system limits dynamic behaviors of colloids, enhancing stability. This platform demonstrates outstanding stability, with relative standard deviation of 2.12 %. Its versatility is showcased through the quantitative detection of melamine in milk, 6-thioguanine in serum, and histamine in beer, demonstrating its capability for accurate, real-time detection in complex matrices. This continuous and online Ag SERS platform represents a significant advancement in reliable, high-performance analyte detection, offering promising prospects for real-time analytical applications and providing a cost-effective, scalable solution for widespread use.

PMID:40972276 | DOI:10.1016/j.talanta.2025.128832

RSC Adv. 2025 Sep 10;15(39):32833-32870. doi: 10.1039/d5ra05615b. eCollection 2025 Sep 5.

ABSTRACT

Emerging contaminants (ECs), including pharmaceuticals, endocrine disruptors, heavy metals, and per- and polyfluoroalkyl substances (PFAS), are becoming increasingly crucial to identify because of their toxicity, persistence, and resistance to traditional water treatment techniques. Even if they are accurate, traditional analytical methods are frequently costly, time-consuming, and instrumentally complex. With its ease of use, quick visual reaction, high sensitivity, and affordability, colorimetric sensing based on gold nanoparticles (AuNPs) has become a viable substitute in this regard for on-site EC monitoring. The synthesis, functionalization, and use of AuNPs for the colorimetric detection of new pollutants have advanced recently, as this review illustrates. Because of their special localized surface plasmon resonance (LSPR) characteristics, AuNPs can interact with target analytes to produce noticeable color changes. We talk about different synthesis techniques, such as the reduction of citrate and borohydride, and how they affect the optical characteristics and particle shape. Additionally, we investigate functionalization techniques that provide selectivity toward ECs using thiol ligands, DNA aptamers, polymers, and chelating agents. A thorough analysis is conducted of colorimetric detection techniques, encompassing both aggregation-based and non-aggregation-based systems. Detecting ions (cation, anion), pesticides, metals (heavy metals, alkali and alkaline earth metals, coinage metals, rare-earth metals), food (formalin, melamine, rhodamine dye, etc.), pathogens, mycotoxins, oligonucleotides (DNA, nucleic acids, protein, etc.), glucose, and drugs (antibiotics, allergens, etc.) has been examined in this review. Lastly, we discuss present issues such as probe stability and matrix interference and suggest future paths for the development of portable and field-deployable sensors.

PMID:40936959 | PMC:PMC12422228 | DOI:10.1039/d5ra05615b

RSC Adv. 2025 Sep 10;15(39):32833-32870. doi: 10.1039/d5ra05615b. eCollection 2025 Sep 5.

ABSTRACT

Emerging contaminants (ECs), including pharmaceuticals, endocrine disruptors, heavy metals, and per- and polyfluoroalkyl substances (PFAS), are becoming increasingly crucial to identify because of their toxicity, persistence, and resistance to traditional water treatment techniques. Even if they are accurate, traditional analytical methods are frequently costly, time-consuming, and instrumentally complex. With its ease of use, quick visual reaction, high sensitivity, and affordability, colorimetric sensing based on gold nanoparticles (AuNPs) has become a viable substitute in this regard for on-site EC monitoring. The synthesis, functionalization, and use of AuNPs for the colorimetric detection of new pollutants have advanced recently, as this review illustrates. Because of their special localized surface plasmon resonance (LSPR) characteristics, AuNPs can interact with target analytes to produce noticeable color changes. We talk about different synthesis techniques, such as the reduction of citrate and borohydride, and how they affect the optical characteristics and particle shape. Additionally, we investigate functionalization techniques that provide selectivity toward ECs using thiol ligands, DNA aptamers, polymers, and chelating agents. A thorough analysis is conducted of colorimetric detection techniques, encompassing both aggregation-based and non-aggregation-based systems. Detecting ions (cation, anion), pesticides, metals (heavy metals, alkali and alkaline earth metals, coinage metals, rare-earth metals), food (formalin, melamine, rhodamine dye, etc.), pathogens, mycotoxins, oligonucleotides (DNA, nucleic acids, protein, etc.), glucose, and drugs (antibiotics, allergens, etc.) has been examined in this review. Lastly, we discuss present issues such as probe stability and matrix interference and suggest future paths for the development of portable and field-deployable sensors.

PMID:40936959 | PMC:PMC12422228 | DOI:10.1039/d5ra05615b

RSC Adv. 2025 Sep 10;15(39):32833-32870. doi: 10.1039/d5ra05615b. eCollection 2025 Sep 5.

ABSTRACT

Emerging contaminants (ECs), including pharmaceuticals, endocrine disruptors, heavy metals, and per- and polyfluoroalkyl substances (PFAS), are becoming increasingly crucial to identify because of their toxicity, persistence, and resistance to traditional water treatment techniques. Even if they are accurate, traditional analytical methods are frequently costly, time-consuming, and instrumentally complex. With its ease of use, quick visual reaction, high sensitivity, and affordability, colorimetric sensing based on gold nanoparticles (AuNPs) has become a viable substitute in this regard for on-site EC monitoring. The synthesis, functionalization, and use of AuNPs for the colorimetric detection of new pollutants have advanced recently, as this review illustrates. Because of their special localized surface plasmon resonance (LSPR) characteristics, AuNPs can interact with target analytes to produce noticeable color changes. We talk about different synthesis techniques, such as the reduction of citrate and borohydride, and how they affect the optical characteristics and particle shape. Additionally, we investigate functionalization techniques that provide selectivity toward ECs using thiol ligands, DNA aptamers, polymers, and chelating agents. A thorough analysis is conducted of colorimetric detection techniques, encompassing both aggregation-based and non-aggregation-based systems. Detecting ions (cation, anion), pesticides, metals (heavy metals, alkali and alkaline earth metals, coinage metals, rare-earth metals), food (formalin, melamine, rhodamine dye, etc.), pathogens, mycotoxins, oligonucleotides (DNA, nucleic acids, protein, etc.), glucose, and drugs (antibiotics, allergens, etc.) has been examined in this review. Lastly, we discuss present issues such as probe stability and matrix interference and suggest future paths for the development of portable and field-deployable sensors.

PMID:40936959 | PMC:PMC12422228 | DOI:10.1039/d5ra05615b

RSC Adv. 2025 Sep 5;15(39):32031-32040. doi: 10.1039/d5ra03280f. eCollection 2025 Sep 5.

ABSTRACT

Melamine is an additive used fraudulently to enrich foods with nitrogen, particularly in the dairy industry. It is also known as the main metabolite or degradation phytosanitary product of cyromazine. However, the numerous incidents involving living beings in aquatic environments, children and pets fed with products made from melamine in China and certain African countries have led to distrust of melamine in food. In order to ensure strong food safety and security, and good quality of the ecosystem free of melamine, it is important to design a fast, simple, reliable and efficient method for the detection of melamine. For this purpose, silver nanoparticles capped with l-cysteine functionalized carbon dots (cCDs/AgNPs) were designed for the detection of melamine. The results showed that a yellow solution of cCDs/AgNPs turns pink and gradually blue within two minutes of heating at 90 °C in the presence of melamine even at a concentration of 0.1 μg mL^-1. This color change reflects the sensitivity of cCDs/AgNPs towards melamine. The investigation of cCDs/AgNPs-based on ultraviolet-visible spectroscopy exhibits good linearity in the range from 0.5 μg mL^-1 to 4.5 μg mL^-1 for melamine detection, with a detection limit of 0.03 μg mL^-1. This method was successfully applied to determine melamine in a milk matrix, suggesting that this method can be applied for food monitoring with the aim of obtaining melamine-free food in dairy products.

PMID:40918312 | PMC:PMC12412118 | DOI:10.1039/d5ra03280f

Small Methods. 2025 Nov;9(11):e01445. doi: 10.1002/smtd.202501445. Epub 2025 Sep 2.

ABSTRACT

The binding of small molecules to DNA may represent a mutagenic process capable of inducing genomic structural alterations and functional impairment. Melamine (MA), a toxic small molecule, exhibits a hydrogen-bonding interface structurally analogous to adenine, enabling to form non-canonical thymine-melamine (T-MA) base pairs like Watson-Crick pairing. This property allows MA to program DNA nanostructure formation. Given MA's documented biological consequences, such as kidney disease, reproductive toxicity, and central nervous system dysfunction, sensitive detection of MA-DNA interactions has become critically important. However, such subtle structural changes remain challenging to identify because of the paucity of effective detection approaches in a high-resolution manner. To overcome this limitation, nanopore measurement is employed to identify T-MA hydrogen bonding base pairing in DNA. Results demonstrate that nanopore enables unambiguous identification of T-MA hydrogen bonding via mechanically unzipping thymine-melamine-thymine (T-MA-T) triplets in DNA structures. The approach achieves single-base-pair resolution, as evidenced by nucleotide substitutions flanking the abasic site in complex DNA structures. In addition, nanopore-based kinetic analysis reveals an enhanced intramolecular stability in MA-binding DNA compared to those consisting of complete canonical DNA pairs. This research establishes a powerful platform for high-resolution interrogation of DNA-small molecule interactions and quantitative biophysical characterization of mutagenic modifications at the nanoscale.

PMID:40891541 | DOI:10.1002/smtd.202501445

Food Sci Nutr. 2025 Aug 25;13(9):e70831. doi: 10.1002/fsn3.70831. eCollection 2025 Sep.

ABSTRACT

Melamine (MEL) and cyanuric acid (CYA) are contaminants that can enter the human body through dietary sources, raising significant toxicological concerns, particularly for infants. MEL undergoes minimal biotransformation in the human body. While breast milk is widely recognized as the optimal source of nutrition for infants, it may also serve as a potential route for the transmission of contaminants. This study aimed to quantify the concentrations of MEL and CYA in breast milk and assess the associated non-carcinogenic toxicity risks for infants aged 0-6 months. A total of 100 mothers from Hamadan, Iran, who exclusively breastfed their infants aged 15-150 days, were included. Breast milk samples, ranging from 10 to 50 mL, were manually expressed. The results revealed that 77% of the samples contained MEL, while 84% contained CYA, both exceeding the detection limits. The average concentrations of MEL and CYA were 730 ± 26 and 400 ± 38 ng mL^-1, respectively. Risk assessment indicated that none of the infant groups exhibited a hazard quotient (HQ) or cumulative risk (hazard index) from MEL and CYA exposure. According to Monte Carlo simulation, the 95th percentile of HQ for MEL and CYA in breast milk were 0.00561 and 0.0000154, respectively, both well below the safety threshold (HQ < 1). These findings suggest that breast milk consumption by infants up to 6 months of age in Hamadan does not pose a significant risk in terms of MEL and CYA exposure.

PMID:40873966 | PMC:PMC12378073 | DOI:10.1002/fsn3.70831

J Hazard Mater. 2025 Oct 5;497:139514. doi: 10.1016/j.jhazmat.2025.139514. Epub 2025 Aug 18.

ABSTRACT

Previous studies have found that melamine tableware workers are exposed to high levels of airborne melamine, which is linked to increased urinary markers of oxidative stress and kidney injury. However, the effectiveness of engineering controls in reducing such exposures had not been evaluated. To address this, an intervention was conducted in October 2016, installing two local exhaust systems combined with airflow containment curtains and a large open-end fan in high-exposure areas. Twenty-two workers were monitored before (March-April 2016) and after the intervention (November 2016). A total of 1834 air and urine samples were collected and analyzed. After the intervention, median personal melamine concentrations dropped from 159.12 to 4.51 µg/m³ (p < 0.0001), and formaldehyde levels declined from 215.99 to 162.16 µg/m³ (p = 0.002), representing 97.2 % and 24.6 % reductions, respectively. Generalized estimating equation models revealed significant decreases in diurnal urinary melamine (β = -7.02; p = 0.043) and MDA (β = -0.47; p < 0.001), though the reduction in 8-OHdG was not statistically significant (β = -0.34; p = 0.074). These results suggest that our engineering installations are effective in reducing airborne melamine exposure and short-term oxidative stress, though further research is needed to evaluate long-term health effects.

PMID:40865217 | DOI:10.1016/j.jhazmat.2025.139514

Food Chem. 2025 Nov 30;493(Pt 4):145933. doi: 10.1016/j.foodchem.2025.145933. Epub 2025 Aug 13.

ABSTRACT

Malachite green (MG) is a toxic contaminant commonly found in aquaculture, making its effective removal and detection crucially important. In this study, MIL-100(Fe) was synthesized via a microwave-assisted hydrothermal method under optimized conditions (150 °C, 200 W, 30 min; FeCl₃·6H₂O:H₃BTC = 2:3). The resulting material exhibited excellent structural stability, a high specific surface area (1169.9 m²/g), and a remarkable MG adsorption capacity of 714.29 mg/g. To enable practical application and reusability, MIL-100(Fe) was immobilized onto a melamine sponge (MeS) using polyvinylidene fluoride (PVDF) as binding agent, forming a recyclable MeS/PVDF/MOF composite. When applied for solid-phase extraction of MG in conjunction with UV detection, the composite demonstrated high recovery rates (92.1-99.4 %), a low detection limit (2.29 μg/L), and consistent performance with over 80 % recovery after six reuse cycles in both real fish and wastewater samples. This study presents a simple, efficient and sustainable strategy for the adsorption and detection of MG in aquatic food matrices.

PMID:40848346 | DOI:10.1016/j.foodchem.2025.145933

Data Brief. 2025 Aug 6;62:111965. doi: 10.1016/j.dib.2025.111965. eCollection 2025 Oct.

ABSTRACT

Wood based panels are widely used in construction and furniture due to their cost effectiveness, sustainability, and processability. However, adhesives and additives used in these engineered materials may release volatile organic compounds (VOCs), including formaldehyde and BTEX compounds, affecting indoor air quality. This study presents a dataset examining VOC emissions from three commonly used panels: pine wood board (PWB), low pressure melamine particleboard (LPM), and particleboard (PB), and their potential health impacts in mice. To reflect a real-life early-phase exposure scenario, the panels were not pre-conditioned and were installed on three sides of a 50 × 50 × 50 cm acrylic chamber with passive air exchange only. Air samples were collected nine times over 14 days using automatic thermal desorption gas chromatography/mass spectrometry (ATD GC MS). VOCs were categorized as total VOCs (TVOC), natural VOCs (NVOC), five hazardous VOCs (BTEX plus styrene; 5VOC), and formaldehyde. Male BALB/c mice (n = 4 per group) were continuously exposed to each chamber for 14 days. Body weight was monitored on days 7 and 14, and 21 hematological and serum biochemical parameters were analyzed after exposure. Organs including the liver, kidney, lung, heart, and spleen were weighed and histologically examined. The dataset includes time resolved emission profiles for each panel type, longitudinal body weight measurements, blood and serum biochemical markers, and histological images. VOC emissions varied by material, with detectable formaldehyde in LPM and PB, and predominantly NVOC in PWB. No abnormal behaviors were observed during exposure. Statistically significant differences were noted in some blood parameters and organ weights between control and exposed groups, although all values remained within the normal physiological range. Histopathological analysis likewise revealed no specific abnormalities. This dataset supports future studies on VOC exposure response modeling, regulatory benchmarking, or risk mitigation strategies and contributes to understanding acute biological responses to real world wood panel emissions.

PMID:40837475 | PMC:PMC12361599 | DOI:10.1016/j.dib.2025.111965

Water Res. 2025 Dec 1;287(Pt A):124366. doi: 10.1016/j.watres.2025.124366. Epub 2025 Aug 7.

ABSTRACT

Tire additives and their transformation products (TATPs) are increasingly recognized for their toxicity and widespread environmental presence. However, the interplay of rainfall, seasonal variation, and stream type in governing their multi-media partitioning and risks remains largely unexplored. This study investigated the spatiotemporal distribution, environmental drivers, and ecological risks of 21 TATPs in three distinct urban streams (general road, expressway, and rural road-adjacent). Seventeen, 19, and 14 TATPs were quantified in water (514-6541 ng/L), suspended particulate matter (SPM, 12.8-244 ng/L), and sediment (1.71-248 ng/g), respectively. Rainfall significantly altered aqueous TATP levels, while stream type and seasonal variation influenced TATP pollution in SPM and sediment. Multiple linear regression identified pH, temperature, and road area as key aqueous-phase drivers, whereas precipitation and road area controlled the levels of TATPs in SPM and sediment, respectively. Hydrophobicity was a key determinant in TATP multi-media partitioning. High ecological risks were found across all water samples, primarily associated with 1,3-diphenylurea (DPU), 1,3-dicyclohexylurea (DCU), N-(1,3-dimethylbutyl)-N'-phenyl-p-phenylenediamine quinone (6PPD-Q), and hexa(methoxymethyl)melamine (HMMM). Eight TATPs exhibited persistence, bioaccumulation, or toxicity traits, warranting prioritized regulation. These insights are crucial for crafting effective environmental policies to mitigate =TATP impacts and protect urban aquatic ecosystems.

PMID:40819446 | DOI:10.1016/j.watres.2025.124366

J Chromatogr A. 2025 Oct 11;1760:466280. doi: 10.1016/j.chroma.2025.466280. Epub 2025 Aug 9.

ABSTRACT

Melamine-formaldehyde resins are used in various industrial applications. As melamine is a toxic compound on the candidate list of Substances of Very High Concern, its content in melamine-based resins is important. Here we present two high-performance liquid chromatography methods suitable for the determination of free melamine content in uncured non-ionic and negatively charged melamine-based resins. A gradient reversed-phase liquid chromatography method using a C18 column was developed for the determination of free melamine content in non-ionic resins, while an isocratic mixed-mode liquid chromatography method using a Primesep 100 column was developed for the quantification of free melamine in sulfonated melamine-based resins. Both methods utilise ultraviolet detection, which allows the quantification of melamine in melamine-based resins with a limit of quantification of ∼10^-3% by weight and good repeatability and linearity over a wide range of melamine concentrations.

PMID:40818432 | DOI:10.1016/j.chroma.2025.466280

Aquat Toxicol. 2025 Oct;287:107537. doi: 10.1016/j.aquatox.2025.107537. Epub 2025 Aug 10.

ABSTRACT

Concerns over plastic-associated chemical toxicity are increasing amid the plastic pollution crisis. Halogenated flame retardants, though effective in plastic development, are being phased out due to toxicity, while nitrogen-based alternatives, such as melamine cyanurate (MC), are considered more chemically stable and less toxic. Here, we assess the solubility and chemical stability of MC in freshwater using various solvents and evaluate degradation after UV exposure. Additionally, we compare the acute and chronic aquatic toxicity of MC to the more widespread halogenated flame retardant tetrabromophthalic anhydride (TBA) using the Daphnia magna invertebrate model. Toxicity of a common solvent, dimethyl sulfoxide (DMSO), was also assessed. MC was insoluble in 16 of 18 tested solvents, with solubility only seen in a strong acid and base. UV exposure for 72 h within freshwater media indicated minimal degradation, classifying MC as a highly stable compound. Acute toxicity tests at 1-20 mg/L showed no significant difference in EC₅₀ values between TBA (0.16 - 11.46 mg/L) and MC (5.91 - 13.23 mg/L). Chronic toxicity tests at 0.5, 5, and 15 mg/L yielded NOEC values of ≤5 mg/L for TBA and <5 mg/L for MC. At 15 mg/L, chronic exposure to TBA, MC, and DMSO resulted in 100% mortality in D. magna. These findings challenge the assumption that DMSO is a low-toxicity solvent in aquatic testing. Overall, the study highlights the difficulty in assessing the toxicity of highly stable flame retardants like MC, while indicating that they may exhibit similar aquatic toxicity as halogenated congeners.

PMID:40816006 | DOI:10.1016/j.aquatox.2025.107537

Appl Opt. 2025 Jul 10;64(20):5852-5859. doi: 10.1364/AO.561321.

ABSTRACT

Milk adulteration through dilution and the addition of nitrogen-rich chemicals is a persistent issue in the dairy industry, affecting product quality and consumer safety. Current monitoring techniques often rely on protein nitrogen content, which can be misrepresented by these additives. We report a reflective holographic sensor that can directly detect diluted milk by monitoring the shrinkage of the holographic grating, which induces a rapid and reversible blue shift of 34 nm across milk dilutions ranging from 10 to 100 vol%. The holographic milk sensor demonstrates high selectivity, remaining unaffected by variations in fat content, ionic strength, or pH. Testing with various casein suspensions reveals that the shrinkage effect is specifically triggered by calcium caseinate micelles, in marked contrast to free casein slurries in water. Moreover, adding melamine to artificially compensate for the nitrogen loss in diluted milk results in swelling rather than contraction. This holographic sensor offers a reliable and effective tool for quality control in the dairy industry.

PMID:40793746 | DOI:10.1364/AO.561321

Spectrochim Acta A Mol Biomol Spectrosc. 2026 Jan 5;344(Pt 2):126751. doi: 10.1016/j.saa.2025.126751. Epub 2025 Jul 29.

ABSTRACT

Melamine contamination from illegal additives, packaging contaminants, and pesticide residues threatens dairy product safety, demanding rapid detection. Traditional methods such as chromatography or mass spectrometry are precise but lack field applicability due to complexity, time consumption, and cost. Surface-enhanced Raman spectroscopy (SERS) is a promising alternative for sensitive, rapid, and label-free analysis. However, current SERS implementations face challenges like complex substrate synthesis, environmentally harmful sample processing, and lack of discrimination of analogues. Thus, developing a simple SERS-based method for detecting melamine and its analogues without pretreatment remains urgent. In this paper, a straightforward SERS detection method is proposed to achieve accurate and rapid pretreatment-free detection of melamine in milk. Polytetrafluoroethylene‑silver nanospheres (PTFE-AgNPs) SERS substrate is fabricated by mixing silver colloid, sodium hydroxide and sodium chloride solution, followed by deposition onto a PTFE filter membrane by filter-pressing assembly. Additionally, diluted milk is subjected to SERS testing directly without any pretreatment. Furthermore, both qualitative and quantitative analyses were performed using RF, PCA-SVM and CNN. Among the three algorithms, CNN classification model achieved the best accuracy 99.25 % for distinguishing melamine, ammeline, ammelide, and blank controls, while the CNN regression model yielded a coefficient of determination (R²) of 0.9999 for melamine quantification. The limit of detection (LOD) for melamine in milk was 3.32 × 10^-6 M, lower than the World Health Organization (WHO) recommended limit. This method, featuring simple SERS substrate preparation and non-pretreatment, enables rapid and efficient detection of melamine and its analogues, promoting broader applications of SERS in food safety monitoring.

PMID:40749506 | DOI:10.1016/j.saa.2025.126751

Langmuir. 2025 Aug 12;41(31):21144-21160. doi: 10.1021/acs.langmuir.5c03079. Epub 2025 Jul 29.

ABSTRACT

Carbon nitride (g-C₃N₄, CN) is always used as a metal-free catalyst to activate peroxymonosulfate (PMS) without toxic metal ion leaching in solutions. However, it is still a challenge to enhance the catalytic activity for CN. Herein, sulfur (S)-doped g-C₃N₄ is synthesized by a facile method as named CNS_x, where x represents the mass ratio of ammonium sulfate to melamine during the CNS_x synthesis. Partial N atoms such as pyridinic N in CN were replaced by S atoms. CNS_1.75 exhibited an excellent catalytic activity to degrade Rhodamine B (RhB) via PMS activation under the assistance of the visible light (Vis). The rate constant (k) increased about 9 and 7 times for CNS_1.75/Vis/PMS than that of CNS_1.75/PMS and CNS/Vis/PMS systems. Moreover, the k value is higher than that of some metal-doped CN as reported. The toxicity of RhB was effectively reduced after the degradation process with the total organic carbon (TOC) removal ratio 48% after 40 min. The RhB removal efficiency kept 95% after continuous operation for 12 h. The catalytic mechanism was proposed in which ¹O₂ was the dominant reactive oxygen species (ROS).

PMID:40726166 | DOI:10.1021/acs.langmuir.5c03079

Environ Sci Technol. 2025 Aug 12;59(31):16282-16292. doi: 10.1021/acs.est.5c03579. Epub 2025 Jul 28.

ABSTRACT

Melamine (MEL) and its derivatives are known for acute nephrotoxicity, but the risks from chronic exposure and underlying mechanisms of toxicity are unclear. We integrated environmental monitoring (356 pairs of house dust and urine samples collected across mainland China) with cell-based bioassays to investigate MEL exposure sources and toxic effects. MEL-related chemicals were frequently detected in dust (median: 10.3 μg/g) and urine (22.3 ng/mL) samples, indicating their widespread presence in indoor environments and chronic exposure among the Chinese population. Significant positive correlations were observed between MEL-related chemicals and neutrophil gelatinase-associated lipocalin (NGAL), a urinary biomarker of nephrotoxicity. RNA-sequencing of MEL-exposed human kidney-2 (HK-2) cells revealed significant enrichment of the ferroptosis signaling pathway. Further bioassays demonstrated that MEL exposure induces iron-driven mitochondrial lipid peroxidation in HK-2 cells. The system X_c^-/GPX4, ACSL4, and TFR1/DMT1 pathways identified as potential targets in ferroptosis-mediated early renal injury in both acute toxicity experiments and chronic exposure to environmentally relevant concentrations. This finding was further supported by urinary malondialdehyde and Fe²⁺ levels that mediated 13-31% of the effect of MEL-related chemicals on NGAL in humans. Our study provides valuable insights into the role of ferroptosis in chronic kidney injury associated with environmental exposure to MEL and its derivatives.

PMID:40719558 | DOI:10.1021/acs.est.5c03579

Mikrochim Acta. 2025 Jul 28;192(8):531. doi: 10.1007/s00604-025-07422-4.

ABSTRACT

A novel ratiometric fluorescent probe was developed by combining terbium-doped boron/nitrogen co-doped carbon dots (Tb@BNCDs) with thiolated-protected gold nanoclusters (Th@Au NCs) for efficient melamine detection based on a competitive coordination mechanism. The designed system exploits the synergistic effects of aggregation-induced emission (AIE) and Förster resonance energy transfer (FRET) processes. The Tb@BNCDs, formed via coordination of Tb³⁺ ions with the amino and carboxyl groups on BNCDs, serve as both a stable fluorescence source and a coordination site for melamine interaction. Simultaneously, the weakly emissive Th@Au NCs were activated through Tb³⁺-induced aggregation, yielding a hybrid nanostructure exhibiting dual emission peaks at 470 nm and 630 nm. Upon the introduction of melamine, competitive binding to Tb³⁺ ions occurs via melamine's nitrogen-rich triazine structure, disrupting the original coordination complexes. This displacement interferes with AIE and FRET pathways, resulting in quantifiable changes in fluorescence emission intensity ratios (F₄₇₀/F₆₃₀), and enabling ratiometric detection. The probe demonstrates a broad linear detection range (0.01-300 µM), an ultra-low limit of detection (LOD) of 2.6 nM, and rapid response time (~ 1.5 min), outperforming many existing single-signal fluorescent systems. Stability assessments confirmed robust optical performance under varying pH, ionic strength, and UV exposure conditions, though long-term storage stability remains to be evaluated. The probe's high selectivity for melamine was validated against common food matrix interferents. Furthermore, practical applicability was demonstrated by analyzing spiked milk and infant formula samples, yielding satisfactory recoveries and precision, comparable to standard HPLC/UV methods. Overall, this ratiometric fluorescence platform offers a sensitive, rapid, and user-friendly approach for melamine monitoring, with potential for adaptation to other food safety applications through surface modification or doping strategies.

PMID:40719877 | DOI:10.1007/s00604-025-07422-4

J Chromatogr A. 2025 Sep 27;1759:466230. doi: 10.1016/j.chroma.2025.466230. Epub 2025 Jul 17.

ABSTRACT

A novel adsorbent named as MS@CTFs, was successfully synthesized through the Schiff base reaction by immobilizing a covalent triazine framework (CTF) constructed from 2,4,6-tris(4-aminophenyl)-1,3,5-triazine (TAPT) and trimethylformyl resorcinol (TP) onto a melamine sponge (MS) substrate. The innovative design integrated robust triazine-based CTF with an easy-to-use melamine sponge, simplifying the sample preparation procedure and also enhancing the adsorption performance. After optimizing the adsorption parameters, the MS@CTFs demonstrated robust adsorption for enrofloxacin (ENR) from milk matrices, the adsorption capacity was 155.3 mg g^-1. the LOD and LOQ were determined to be 0.032 μg mL^-1 and 0.107 μg mL^-1, respectively. Assessments conducted via GAPI, Complex GAPI, AGREE, and AGREEprep evaluation frameworks validated the method's outstanding environmental sustainability and operational feasibility with AGREE score of 0.67, AGREEprep score of 0.66. Furthermore, the MS@CTFs exhibited highly selective affinity towards cationic dyes. This study underscores the potential of the MS@CTFs as a selective adsorbent with nearly 100 % removal efficiency for the removal of ENR and cationic dyes from aqueous environments, contributing to advancements in milk and water treatment technologies.

PMID:40712455 | DOI:10.1016/j.chroma.2025.466230

J Environ Manage. 2025 Sep;391:126647. doi: 10.1016/j.jenvman.2025.126647. Epub 2025 Jul 19.

ABSTRACT

The challenge of recovering conventional photocatalysts has been addressed by the development of floating variants. However, the underlying molecular mechanisms governing the photocatalytic inactivation of hazardous algae remain poorly understood. This study employed a floating photocatalyst, melamine sponge-loaded bismuth trioxide coupled copper metal-organic framework (MS/Bi₂O₃@Cu-MOF), to efficiently inactivate a representative marine toxic alga, Karenia mikimotoi (K. mikimotoi), under visible light irradiation. Concurrently, Data-Independent Acquisition (DIA) proteomics was systematically applied to investigate differential protein expression throughout the photocatalytic inactivation process. At a loading amount of 0.4 g, an inactivation rate of K. mikimotoi reaching 99.306 % was achieved within 12 h. The MS/Bi₂O₃@Cu-MOF treatment group exhibited significant reductions in the three primary photosynthetic pigments and soluble protein. Furthermore, the relative content of reactive oxygen species (ROS) peaked at 681.45 % at 3 h before declining. Conversely, the specific activities of three key antioxidant enzymes demonstrated substantial increases. Differential protein enrichment analysis revealed that photocatalysis primarily affected the expression of proteins in K. mikimotoi associated with superoxide dismutase (SOD), peroxidase (POD), as well as proteins involved in calcium and potassium ion binding/transport and phospholipid binding. Gene ontology (GO) enrichment analysis revealed that the predominant functional category among the differentially expressed proteins (DEPs) was associated with metal ion binding. Kyoto encyclopedia of genes and genomes (KEGG) pathway enrichment analysis further identified significant involvement of these DEPs in photosynthetic processes within K. mikimotoi. Collectively, this study provides an experimental foundation and theoretical insights at the protein level for understanding the photocatalytic inactivation of harmful algae, offering practical insights for advancing photocatalytic technology in real-world applications.

PMID:40684592 | DOI:10.1016/j.jenvman.2025.126647

Anal Methods. 2025 Jul 24;17(29):6133-6141. doi: 10.1039/d5ay00765h.

ABSTRACT

Melamine (MEL) is frequently adulterated in dairy products to manipulate protein content test results due to its high nitrogen content. In this study, a fluorescent probe based on ofloxacin (OFL) and gold nanoparticles (AuNPs) was proposed for the specific and sensitive detection of MEL. In the pH range of 4.5-7.5, the fluorescence spectrum of OFL exhibits a high degree of overlap with the absorption spectrum of AuNPs, and interactions based on fluorescence resonance energy transfer (FRET) occur, with significant quenching of OFL fluorescence accompanied by a change in fluorescence lifetime. After being incorporated into MEL, the amino group of MEL specifically interacted with the surface of AuNPs through coordination. This interaction triggered the aggregation of AuNPs, which in turn led to the fluorescence recovery of OFL. The detection of melamine was accomplished by quantifying the change in fluorescence intensity of OFL. Under optimized conditions, the MEL concentration exhibited a strong linear relationship with the relative fluorescence intensity of the probe (R² = 0.994) within a range of 0.1 to 1.6 μM. The limit of detection was determined to be 7.28 nM. It is noteworthy that the method was validated in real milk samples, with recovery rates ranging from 98.2% to 107.1%. The method exhibits excellent selectivity and sensitivity for MEL, making it a suitable tool for the environmental detection of milk.

PMID:40663392 | DOI:10.1039/d5ay00765h