A dual-mode composite nanozyme-based cascade colorimetric-fluorescence aptasensor for Salmonella Typhimurium detection.

BACKGROUND: Salmonella Typhimurium poses a serious threat to human health worldwide, necessitating the development of a rapid, sensitive, and convenient method for S. Typhimurium detection. Nanozymes are considered ideal signal report elements, which are extensively used for developing colorimetric methods. However, single-component nanozymes display low catalytic activity, and colorimetric methods are susceptible to environmental interference, reducing the sensitivity and accuracy of detection results. To address these drawbacks, this study constructed a dual-mode composite nanozyme-based cascade colorimetric-fluorescence aptasensor for S. Typhimurium detection in food. RESULTS: In this study, the composite Fe3O4@MIL-100(Fe) nanozymes were successful synthesized and demonstrated substantial peroxide-like activity, with 4.76-fold higher specificity activity (SA) than that of Fe3O4 nanozymes. Then, a glucose oxidase (GOx)-Fe3O4@MIL-100(Fe) cascade reaction was developed for colorimetric detection via an aptamer to facilitate the formation of Fe3O4@MIL-100(Fe)/S. Typhimurium/carboxylated g-C3N4 (CCN)-GOx sandwich complexes. Meanwhile, the fluorescence mode was achieved by measuring the fluorescence intensity of the sandwich complexes. In optimum conditions, the dual-mode detection limits (LOD) were 1.8 CFU/mL (colorimetric mode) and 1.2 CFU/mL (fluorescence mode), respectively, with the S. Typhimurium concentration ranging from 10 CFU/mL to 107 CFU/mL. Finally, the feasibility of the dual-mode colorimetric-fluorescence method was validated via three actual samples, yielding recovery rates of 77.32 % to91.17 % and 82.17 % to 103.7 %, respectively. SIGNIFICANCE AND NOVELTY: This study successfully develops a composite nanozyme-based cascade colorimetric and fluorescence dual-mode aptasensor for S. Typhimurium detection. It presents several distinct benefits, such as a broader linear range (10-107 CFU/mL), a lower LOD value (1.2 CFU/mL), and more accurate results. More importantly, the proposed dual-mode method displays a low LOD in colorimetric mode, demonstrating considerable potential for S. Typhimurium on-site detection in food.

Fluorinated Liquid-Crystal Monomers in Serum from the General Population and Their Impact on Human Health.

Fluorinated liquid-crystal monomers (FLCMs) are a potential emerging class of persistent, bioaccumulative, and toxic compounds. Humans inevitably ingest FLCMs via food and the environment. However, there are limited studies on internal exposure biomonitoring of FLCMs. Herein, we evaluated the estimated daily intakes (EDIs) of FLCMs in the general population based on serum residue levels. For the first time, 38 FLCMs were detected in 314 serum samples from the general population in Beijing, with a median value of 132.48 ng/g of lipid weight (lw). BDPrB is a predominant FLCM in serum. The median EDI of ∑38FLCMs in the general residents was 37.96 pg/kg bw/day. The residual levels of most FLCMs were higher in urban than in suburban areas (p < 0.05). The concentrations of EFPEB, EDPrB, EDFPBB, and PDTFMTFT in serum showed positive associations with blood glucose (GLU) (r = 0.126-0.275, p < 0.05). Logistic regression analysis showed that FLCMs were significantly positively correlated with dyslipidemia, with an odds ratio of 2.19; BDPrB was significantly positively correlated with hyperglycemia (OR: 2.48). Overall, the present study suggests the occurrence of FLCMs in the nonoccupational population, and the exposure of certain FLCMs may cause abnormal blood glucose and lipid levels.

Regulated anthocyanin release through novel pH-responsive peptide hydrogels in simulated digestive environment.

The instability of anthocyanins significantly reduces their bioavailability as food nutrients. This proof-of-concept study aimed to develop efficient carriers for anthocyanins to overcome this challenge. Characterization of the hydrogels via SEM (scanning electron microscope) and rheological analysis revealed the formation of typical gel structures. MTT (methyl thiazolyl tetrazolium) and hemolysis assays confirmed that their high biocompatibility. Encapsulation efficiency analysis and fluorescence microscopy images demonstrated successful and efficient encapsulation of anthocyanins by pH-responsive hydrogels. Stability studies further validated the effect of peptide hydrogels in helping anthocyanin molecules withstand factors such as gastric acid, high temperatures, and heavy metals. Subsequently, responsive studies in simulated gastric (intestinal) fluid demonstrated that the pH-responsive peptide hydrogels could protect anthocyanin molecules from gastric acid while achieving rapid and complete release in intestinal fluid environments. These results indicate that these peptide hydrogels could stabilize anthocyanins and facilitate their controlled release, potentially leading to personalized delivery systems.

Identification of diagnostic biomarkers of rheumatoid arthritis based on machine learning-assisted comprehensive bioinformatics and its correlation with immune cells.

Background: Rheumatoid arthritis (RA) is a chronic systemic autoimmune disease characterized by inflammatory cell infiltration, which can lead to chronic disability, joint destruction and loss of function. At present, the pathogenesis of RA is still unclear. The purpose of this study is to explore the potential biomarkers and immune molecular mechanisms of rheumatoid arthritis through machine learning-assisted bioinformatics analysis, in order to provide reference for the early diagnosis and treatment of RA disease. Methods: RA gene chips were screened from the public gene GEO database, and batch correction of different groups of RA gene chips was performed using Strawberry Perl. DEGs were obtained using the limma package of R software, and functional enrichment analysis such as gene ontology (GO), Kyoto Encyclopedia of Genes and Genomes (KEGG), disease ontology (DO), and gene set (GSEA) were performed. Three machine learning methods, least absolute shrinkage and selection operator regression (LASSO), support vector machine recursive feature elimination (SVM-RFE) and random forest tree (Random Forest), were used to identify potential biomarkers of RA. The validation group data set was used to verify and further confirm its expression and diagnostic value. In addition, CIBERSORT algorithm was used to evaluate the infiltration of immune cells in RA and control samples, and the correlation between confirmed RA diagnostic biomarkers and immune cells was analyzed. Results: Through feature screening, 79 key DEGs were obtained, mainly involving virus response, Parkinson's pathway, dermatitis and cell junction components. A total of 29 hub genes were screened by LASSO regression, 34 hub genes were screened by SVM-RFE, and 39 hub genes were screened by Random Forest. Combined with the three algorithms, a total of 12 hub genes were obtained. Through the expression and diagnostic value verification in the validation group data set, 7 genes that can be used as diagnostic biomarkers for RA were preliminarily confirmed. At the same time, the correlation analysis of immune cells found that γδT cells, CD4+ memory activated T cells, activated dendritic cells and other immune cells were positively correlated with multiple RA diagnostic biomarkers, CD4+ naive T cells, regulatory T cells and other immune cells were negatively correlated with multiple RA diagnostic biomarkers. Conclusions: The results of novel characteristic gene analysis of RA showed that KYNU, EVI2A, CD52, C1QB, BATF, AIM2 and NDC80 had good diagnostic and clinical value for the diagnosis of RA, and were closely related to immune cells. Therefore, these seven DEGs may become new diagnostic markers and immunotherapy markers for RA.

Comparison of sea buckthorn fruit oil nanoemulsions stabilized by protein-polysaccharide conjugates prepared using ß-glucan from various sources.

To understand the influence of ß-glucans structure on the emulsifying properties of protein-polysaccharide conjugates, sodium caseinate (NaCas) was utilized to form glycosylation conjugates with varying degrees of glycosylation (10.68-17.50%) using three ß-glucans from bacteria, yeast, and oats. This process induced alterations in the secondary structure of protein. The nanoemulsions prepared with the glycosylated conjugates exhibited superior stability compared to those formulated solely with NaCas, particularly under conditions of drastic pH fluctuations and extended storage periods. The nanoemulsion prepared with the NaCas-Salecan conjugate demonstrated exceptional stability at pH 4 and 6, or storage for 20 days. Additionally, it significantly attenuated the oxidation of unsaturated fatty acids and exhibited the lowest levels of aggregation, flocculation, and free fatty acid release rate during in vitro digestion. This study suggested the potential of the NaCas-Salecan conjugates in enhancing the stability of nanoemulsions and facilitating the colorectal-targeted delivery of sea buckthorn fruit oil.

Exploring organophosphate ester contamination and distribution in food: A meta-analysis.

This study examines the food safety risk of organophosphate esters (OPEs) by analyzing data from 23 studies with 14,915 data points. We found EDP contamination highest in cereals, dairy, and meats, and TEHP most prevalent in vegetables and fruits, with contamination levels reaching 4.54 ng/g and 1.46 ng/g, respectively. Food processing influences OPE contamination through complex and multifaceted, akin to a "double-edged sword.", as meta-analysis and Principal Component Analysis (PCA) revealed. Estimated Dietary Intakes (EDI) identified vegetables and cereals as primary OPE sources, contributing 33.3% and 23.8% of total intake, with EDI values of 44.74 ng/kg bw/day and 32.25 ng/kg bw/day, respectively. Current exposure levels are within U.S. EPA safety thresholds (HQ < < 1), but the heightened risk to infants and children necessitates revising safety standards and ongoing monitoring.

S/O/W Emulsion with CAPE Ameliorates DSS-Induced Colitis by Regulating NF-κB Pathway, Gut Microbiota and Fecal Metabolome in C57BL/6 Mice.

Inflammatory bowel disease (IBD) has attracted much attention worldwide due to its prevalence. In this study, the effect of a solid-in-oil-in-water (S/O/W) emulsion with Caffeic acid phenethyl ester (CAPE, a polyphenolic active ingredient in propolis) on dextran sulfate sodium (DSS)-induced colitis in C57BL/6 mice was evaluated. The results showed that CAPE-emulsion could significantly alleviate DSS-induced colitis through its effects on colon length, reduction in the disease activity index (DAI), and colon histopathology. The results of ELISA and Western blot analysis showed that CAPE-emulsion can down-regulate the excessive inflammatory cytokines in colon tissue and inhibit the expression of p65 in the NF-κB pathway. Furthermore, CAPE-emulsion promoted short-chain fatty acids production in DSS-induced colitis mice. High-throughput sequencing results revealed that CAPE-emulsion regulates the imbalance of gut microbiota by enhancing diversity, restoring the abundance of beneficial bacteria (such as Odoribacter), and suppressing the abundance of harmful bacteria (such as Afipia, Sphingomonas). The results of fecal metabolome showed that CAPE-emulsion restored the DSS-induced metabolic disorder by affecting metabolic pathways related to inflammation and cholesterol metabolism. These research results provide a scientific basis for the use of CPAE-emulsions for the development of functional foods for treating IBD.

Universal organophosphate pesticides detection by peptide based fluorescent probes.

In practical applications, the rapid and efficient detection of universal organophosphorus pesticides (OPs) can assist inspectors in quickly identifying the presence of OPs in samples. However, this presents a challenge for most well-established methods, typically designed to detect only a specific type of organophosphorus molecule at a time. In this proof-of-concept study, we draw inspiration from the structural similarities among OPs to develop innovative peptide-based fluorescence probes for the first time, which could efficiently detect a broad range of OPs within a mere 3 min. Analysis of fluorescence curve fitting reveals a clear linear correlation between the fluorescent intensity of the peptide probes and the concentration of OPs. Additionally, the selectivity analysis indicates that these peptide fluorescent probes exhibit an excellent response to various OPs while maintaining sufficient selectivity for detecting other pesticide types. Accurate sample analysis has also highlighted the potential of these peptide probes as practical tools for the rapid detection of OPs in actual vegetable samples. In summary, this proof-of-concept study presents an innovative approach to designing and developing ultrafast, universally peptide-based OP probes. These custom-designed peptide probes may facilitate rapid sample screening and offer initial quantification for OPs, potentially saving valuable time and effort in practical OP detection.

Facile fabrication of a novel, photodetachable salecan-based hydrogel dressing with self-healing, injectable, and antibacterial properties based on metal coordination.

Achieving the controllable detachment of polysaccharide-based wound dressings is challenging. In this study, a novel, photodetachable salecan-based hydrogel dressing with injectable, self-healing, antibacterial, and wound healing properties was developed using a green and facile approach. A salecan hydrogel with a uniform porous structure and water content of 90.4 % was prepared by simply mixing salecan and an Fe3+-citric acid complexing solution in an acidic D-(+)-glucono-1,5-lactone environment. Metal coordinate interactions were formed between the released Fe3+ ions and carboxyl groups on the salecan polysaccharide, inducing homogeneous gelation. Benefiting from this dynamic and reversible crosslinking, the salecan hydrogel exhibited self-healing and injectable behavior, facilitating the formation of the desired shapes in situ. The exposure of Fe3+-citric acid to UV light (365 nm) resulted in the reduction of Fe3+ to Fe2+ through photochemical reactions, enabling phototriggered detachment. Moreover, the hydrogel exhibited excellent biocompatibility and satisfactory antibacterial efficacy against Escherichia coli and Staphylococcus aureus of 72.5 % and 85.3 %, respectively. The adhesive strength of the salecan hydrogel to porcine skin was 1.06 ± 0.12 kPa. In vivo wound healing experiments further highlighted the advantages of the prepared hydrogel in alleviating the degree of wound inflammation and promoting tissue regeneration within 12 days.

Complex insoluble dietary fiber alleviates obesity and liver steatosis, and modulates the gut microbiota in C57BL/6J mice fed a high-fat diet.

BACKGROUND: Obesity has been demonstrated as a risk factor that seriously affects health. Insoluble dietary fiber (IDF), as a major component of dietary fiber, has positive effects on obesity, inflammation and diabetes. RESULTS: In this study, complex IDF was prepared using 50% enoki mushroom IDF, 40% carrot IDF, and 10% oat IDF. The effects and potential mechanism of complex IDF on obesity were investigated in C57BL/6 mice fed a high-fat diet. The results showed that feeding diets containing 5% complex IDF for 8 weeks significantly reduced mouse body weight, epididymal lipid index, and ectopic fat deposition, and improved mouse liver lipotoxicity (reduced serum levels of alanine aminotransferase, aspartate aminotransferase, and alkaline phosphatase), fatty liver, and short-chain fatty acid composition. High-throughput sequencing of 16S rRNA and analysis of fecal metabolomics showed that the intervention with complex IDF reversed the high-fat-diet-induced dysbiosis of gut microbiota, which is associated with obesity and intestinal inflammation, and affected metabolic pathways, such as primary bile acid biosynthesis, related to fat digestion and absorption. CONCLUSION: Composite IDF intervention can effectively inhibit high-fat-diet-induced obesity and related symptoms and affect the gut microbiota and related metabolic pathways in obesity. Complex IDF has potential value in the prevention of obesity and metabolic syndrome. © 2024 Society of Chemical Industry.

Mechanistic investigation and dual-mode colorimetric-chemiluminescent detection of glyphosate based on the specific inhibition of Fe3O4@Cu nanozyme peroxidase-like activity.

In this study, a dual-mode colorimetric/CL nanosensor was developed for glyphosate detection based on the specific inhibition of Fe3O4@Cu peroxidase-like activity. Synthesized Fe3O4@Cu exhibited high levels of peroxidase-like activity that triggered the oxidation of luminol/3,3',5,5'-tetramethyl benzidine dihydrochloride (TMB) to excited-state 3-aminophthalic acid/blue oxTMB, thereby delivering a CL signal/visible colorimetric signal, however, the presence of glyphosate inhibited this activity, resulting in a decrease in signal strength. In-depth investigation revealed that this inhibitory mechanism occurs via two pathways: one in which glyphosate chelates with Fe(III)/Cu(II) and occupy the catalytical active sites of Fe3O4@Cu, thereby decreasing the generation of OH, and another in which glyphosate competes with TMB to consume generated OH, thus reducing the oxidation of TMB. This mechanism formed the basis of our novel dual-mode colorimetric/CL glyphosate nanosensor, which achieved limits of detection (LODs) of 0.086 µg/mL and 0.019 µg/mL in tests, thus demonstrating its significant potential for on-site glyphosate monitoring.

Phase Transition Behaviors of Poly(N-isopropylacrylamide) Nanogels with Different Compositions Induced by (-)-Epigallocatechin-3-gallate and Ethyl Gallate.

Phase transition behaviors of poly(N-isopropylacrylamide) nanogels with different compositions induced by (-)-epigallocatechin-3-gallate (EGCG) and ethyl gallate (EG) has been investigated systematically. Monodisperse poly(N-isopropylacrylamide-co-N-hydroxymethyl acrylamide) (P(NIPAM-co-NMAM)) and poly(N-isopropylacrylamide-co-2-hydroxyethyl methacrylate) (P(NIPAM-co-HEMA)) nanogels with different feeding monomer ratios were prepared by emulsion polymerization. P(NIPAM-co-NMAM) nanogels exhibit rapid isothermal phase transition behavior in EGCG solutions with low concentration (10-3 mol/L) in less than 10 minutes. The thermosensitive phase transition behaviors of nanogels are affected not only by the copolymerized monomers but also by the concentrations of EGCG and EG in aqueous solutions. Nanogels remain in a shrunken state and do not exhibit thermosensitive phase transition behaviors in EGCG solutions (≥5 mmol/L), whereas they display thermo-responsive phase transition behaviors in EG solutions. The volume phase transition temperature (VPTT) shifts to lower temperatures with increasing EG concentration. The diameters of P(NIPAM-co-NMAM) nanogels decrease with increasing EG concentration at temperatures between 29 and 33 °C. In contrast, the diameters of P(NIPAM-co-HEMA) nanogels increase with increasing EGCG concentration at temperatures between 37 and 45 °C. The results demonstrate the potential of nanogels for simple detection of EG and EGCG concentrations in aqueous solutions over a wide temperature range, and EGCG can serve as a signal for the burst-release of drugs from the P(NIPAM-co-NMAM)-based carriers at physiological temperature.

Organophosphorus pesticide contaminants in fruits and vegetables: A meta-analysis.

The worldwide demand for organophosphorus pesticides (OPs) in food production has raised concerns about pesticide residues. Meta-analysis, proven effective in assessing contaminants like aflatoxins and organotin compounds, is applied here to comprehensively study OP contamination in fresh fruits and vegetables. Employing Comprehensive Meta-Analysis V3.0 software, we meticulously examined 24 relevant articles encompassing 69,467 data points. Our findings revealed that while the residual concentrations of OPs (such as chlorpyrifos and profenofos) in most fruits and vegetables have typically met international or national safety standards, including Codex Alimentarius Commission, European Union, British, and Chinese standards, there are some instances in which the maximum residue limits have been exceeded, posing safety risks. Therefore, significant efforts are required to maintain residual OP contamination at safe concentrations.

Enhancing the stability of natural anthocyanins against environmental stressors through encapsulation with synthetic peptide-based gels.

The instability of anthocyanin to environmental stressors severely limits its applications as a natural bioactive pigment. To overcome these limitations, this proof-of-concept study utilizes the high biocompatibility of peptide molecules and the unique gel microstructure to develop innovative peptide-based gels. Characterization of the gels was conducted through AFM, SEM, rheological analysis, and CD spectrum. These analyses confirmed the fibrous mesh structure and impressive mechanical strength of the peptide-based gels. The cytotoxicity evaluation using MTT and hemolysis analysis showed high biocompatibility. Encapsulation efficiency analysis and fluorescence microscopy images demonstrated successful and efficient encapsulation of anthocyanins in all four peptide-based gels, with uniform distribution. Moreover, systematic investigations were conducted to assess the impact of peptide-based gels on the stability of natural anthocyanins under environmental stressors such as temperature, pH variations, and exposure to metal ions. Notably, the results revealed a significant enhancement in stability, including improved long-term storage and antioxidant activity. In conclusion, this study successfully developed four novel peptide-based gels that effectively protect natural anthocyanins from environmental stressors, highlighting their potential in various fields such as food and biology.

A robust and facile colorimetric aptasensor for the detection of Salmonella Typhimurium based on the regulation of Fe3O4@Cu@PCPy yolk-shell nanozyme activity.

Due to their superparamagnetism and enzyme-like activity, iron oxide (Fe3O4) nanozymes can be readily used for sample pretreatment and the generation of detection signals, and have, thus, attracted much attention in the field of bioanalysis and diagnosis. However, the low catalytic activity of Fe3O4 nanozymes does reduce the sensitivity of Fe3O4-based methods, limiting their application. In this study, Fe3O4@Cu@poly(pyrrole-2-carboxylic acid) yolk-shell nanozymes (Fe3O4@Cu@PCPy YSNs) were synthesized using a facile approach and selective chemical etching technology. Compared with Fe3O4 nanozymes, the Fe3O4@Cu@PCPy YSNs demonstrated a three-fold increase in the peroxidase-like activity, good dispersity and strong superparamagnetism. In addition, the flower-shaped structure of aptamer-complementary strand (Apt-CS) conjugates was designed on the surface of the Fe3O4@Cu@PCPy YSNs, which effectively inhibited their peroxidase-like activity by creating a physical barrier that hindered the access of substrates to the center of the Fe3O4@Cu@PCPy YSNs. Based on this principle, a robust and facile colorimetric aptasensor was developed for detecting Salmonella Typhimurium. The flower-shaped Apt-CS were dissociated in the presence of S. Typhimurium, promoting the recovery of Fe3O4@Cu@PCPy YSN catalytic activity. Under optimized conditions, this proposed aptasensor successfully detected S. Typhimurium in a linear range of 3 to 3 × 106 CFU/mL, achieving a detection limit of 1 CFU/mL. Finally, the feasibility of this novel aptasensor was further validated by three actual samples, with recoveries of between 84.3% and 102%, thereby demonstrating the huge potential of the proposed aptasensor for detecting S. Typhimurium in foods.

Compartments of roots and mature leaves are key hubs in the connectivity of tea-plant mycobiomes and are influenced by environmental factors and host age.

Understanding the tripartite consortium of crop, mycobiome, and environment is necessary to advance smart farming. Owing to their life cycle of hundreds of years, tea plants are excellent models for studying these entwined relationships; however, observations on this globally important cash crop with numerous health benefits are still rudimentary. Here, the fungal taxa along the soil-tea plant continuum in tea gardens of different ages in famous high-quality tea-growing regions in China were characterized using DNA metabarcoding. Using machine learning, we dissected the spatiotemporal distribution, co-occurrence patterns, assembly, and their associations in different compartments of tea-plant mycobiomes, and further explored how these potential interactions were driven by environmental factors and tree age, and how they influenced the market prices of tea. The results revealed that Compartment niche differentiation was the key driving force behind variation in the tea-plant mycobiome. The mycobiome of roots had the highest specific proportion and convergence and almost did not overlap with the soil. The enrichment ratio of developing leaves to root mycobiome increased with increasing tree age, while mature leaves showed the highest value in the Laobanzhang (LBZ) tea garden with top market prices and displayed the strongest depletion effect on mycobiome association along the soil-tea plant continuum. The balance between determinism and stochasticity in the assembly process was co-driven by compartment niches and life cycle variation. Fungal guild analysis showed that altitude indirectly affected market prices of tea by mediating the abundance of the plant pathogen. The relative importance of plant pathogen and ectomycorrhizae could be used to assess the age of tea. Biomarkers were mainly distributed in soil compartments, and Clavulinopsis miyabeana, Mortierella longata, and Saitozyma sp. may affect the spatiotemporal dynamics of tea-plant mycobiomes and their ecosystem services. Soil properties (mainly total potassium) and tree age indirectly affected the developing leaves via positively influencing the mycobiome of mature leaves. In contrast, the climate directly and significantly drove the mycobiome composition of the developing leaves. Moreover, the proportion of negative correlations in the co-occurrence network positively regulated tea-plant mycobiome assembly, which significantly affected the market prices of tea in the structural equation model with network complexity as hub. These findings indicate that mycobiome signatures play pivotal roles in the adaptive evolution and fungal disease control of tea plants and can help develop better agricultural practices that focus on both plant health and financial profits, and provide a new strategy for assessing tea quality grade and age.

Fluorinated liquid-crystal monomers in paired breast milk and indoor dust: A pilot prospective study.

Fluorinated liquid-crystal monomers (FLCMs), one class of emerging persistent, bioaccumulative and toxic (PBT) compounds, are widely used in liquid-crystal displays (LCDs). As a result, they have been found in the environment and serum from occupational workers. However, little is known about their occurrence in non-occupational exposing populations. Herein, we provided an evaluation of the health risks of FLCMs for infants based on breastfeeding exposure and dust ingestion. The detection frequencies (DF) of FLCMs in indoor dust and breast milk was 100 %, with median concentrations of 12.00 ng/g dry weight (dw) and 133.40 ng/g lipid weight (lw), respectively. 1-butoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl)benzene (BDPrB) was the predominant pollutant in indoor dust and human breast milk. Significant positive correlations were observed between the dust concentrations of seven FLCMs including BDPrB, and their breast milk concentrations (r = 0.275-0.660, P < 0.05). Further, associations were also found in some demographic and behavioral factors and concentrations of some FLCMs (P < 0.05). The highest EDI of ∑FLCMs was observed for infants who were < 1 month of age, with a median breast milk intake of 700.35 ng/kg bw/day, in which 1-ethoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl)benzene (EDPrB), BDPrB, and 4'-[(trans, trans)-4'-butyl[1,1'-bicyclohexyl]-4-yl]-3,4-difluoro-1,1'-biphenyl (BBDB) collectively contributed 94.4 % of the total EDIs. Notably, the lactational intake of FLCMs was higher than that of some environmental pollutants (EPs). Overall, our results suggest higher exposure risks for infants and breastfeeding is the predominant exposure route for daily intake of FLCMs for infants.

Metabolic profiling of the fluorinated liquid-crystal monomer 1-ethoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl)benzene.

1-Ethoxy-2,3-difluoro-4-(trans-4-propylcyclohexyl)benzene (EDPrB) is a typical fluorinated liquid-crystal monomer (LCM). LCMs contaminants are becoming increasingly concerning due to their potential persistence, bioaccumulation, toxicity, and broad prevalence in environmental and human samples. However, LCM metabolism is poorly understood. Herein, by introducing selected EDPrB into the appropriate liver microsomes in vitro, we examined the metabolic pathways of LCM in humans, rats, pigs, Cyprinus carpio, crucian carp, and Channa argus. A total of 20 species-dependent metabolites were identified and structurally elucidated by gas and liquid chromatography-high resolution mass spectrometry for the first time. Dealkylation, H-abstraction, and hydroxylation reactions are the primary metabolic pathways. Half of these in vitro metabolites were found in the urine, serum, and fecal samples of Sprague-Dawley rats exposed to EDPrB. Toxicity predictions indicate that 17 metabolites can be classified as toxic. According to the Ecological Structure Activity Relationships (ECOSAR), a number of metabolites exhibit equivalent or greater aquatic toxicity to that of EDPrB. Toxicity Estimation Software Tool (T.E.S.T.) predicts that some metabolites exhibit developmental toxicity and mutagenicity in rats. These findings suggest that biotransformation should be particularly emphasized, and more toxicological and monitoring studies should be performed to assess the ecological and human safety of LCMs.

A Dual-Mode Method Based on Aptamer Recognition and Time-Resolved Fluorescence Resonance Energy Transfer for Histamine Detection in Fish.

Histamine produced via the secretion of histidine decarboxylase by the bacteria in fish muscles is a toxic biogenic amine and of significant concern in food hygiene, since a high intake can cause poisoning in humans. This study proposed a fluorometric and colorimetric dual-mode specific method for the detection of histamine in fish, based on the fluorescence labeling of a histamine specific aptamer via the quenching and optical properties of gold nanoparticles (AuNPs). Due to the fluorescence resonance energy transfer phenomenon caused by the proximity of AuNPs and NaYF4:Ce/Tb, resulting in the quenching of the fluorescence signal in the detection system, the presence of histamine will compete with AuNPs to capture the aptamer and release it from the AuNP surface, inducing fluorescence recovery. Meanwhile, the combined detection of the two modes showed good linearity with histamine concentration, the linear detection range of the dual-mode synthesis was 0.2-1.0 µmol/L, with a detection limit of 4.57 nmol/L. Thus, this method has good selectivity and was successfully applied to the detection of histamine in fish foodstuffs with the recoveries of 83.39~102.027% and 82.19~105.94% for Trichiurus haumela and Thamnaconus septentrionalis, respectively. In addition, this method was shown to be simple, rapid, and easy to conduct. Through the mutual verification and combined use of the two modes, a highly sensitive, rapid, and accurate dual-mode detection method for the analysis of histamine content in food was established, thereby providing a reference for the monitoring of food freshness.

Caffeic acid phenethyl ester loaded in a targeted delivery system based on a solid-in-oil-in-water multilayer emulsion: Characterization, stability, and fate of the emulsion during in vivo digestion.

Many studies have shown that caffeic acid phenethyl ester (CAPE) has various functions, such as antioxidant, anti-inflammatory and anticancer activity, but its low bioavailability and stability limit its application. In this study, the colorectal targeted delivery system for CAPE based on a solid-in-oil-in-water (S/O/W) multilayer emulsion was prepared using CAPE-loaded nanoparticles as the solid phase, coconut oil as the oil phase, and a mixture of lecithin and sodium caseinate as the aqueous phase. The stability of the O/W interfacial layer was improved by using a sodium casein-lecithin mixture as the aqueous surface layer in the preparation. This S/O/W emulsion is a spherical droplet with an S/O/W trilayer structure with a particle size of 155.5 ± 0.72 nm and a polydispersity index (PDI) of 0.24 ± 0.01. The Fourier transform infrared (FTIR) results confirmed that CAPE was successfully loaded into the S/O/W emulsion. This S/O/W emulsion was able to maintain a stable liquid state at pH 6.00-7.4 or cholate concentration of 0-50 mg/mL but showed a gel state at pH 2.0-3.0. The storage experiments demonstrated that the S/O/W emulsion was stable for 15 days at 4 °C, but was prone to agglomeration and emulsion breakage at 25 °C. The in vivo digestion process indicated that the S/O/W emulsion was gradually digested in the digestive tract and released solid phase nanoparticles in the large intestine. Therefore, this newly developed targeted delivery system can effectively deliver CAPE to the colorectum and achieve a 12-hour delayed release, which improved the bioavailability and activity of CAPE.