Effects of quaternization sites and crossing methods on the slow-release and antibacterial effects of hydroxypropyltrimethyl ammonium chloride chitosan/dialdehyde chitosan-based film.

In this study, the active food packaging film were prepared using hydroxypropyltrimethyl ammonium chloride chitosan with different substitution sites (O-HACC & N-HACC) and dialdehyde chitosan (DCS) grafted with protocatechuic acid (PA). To explore the effect of chitosan quaternization positions and crosslinking approaches on the slow-release and antibacterial properties, the double-crosslinked film were fabricated through the self-coupling reaction of PA and Schiff base reaction between amino groups on HACC and aldehyde groups on DCS. The HACC/DCS-based film exhibited stable porous three-dimensional networks with high nisin loading ratios (>90 %). With the participation of the catechol-catechol structure, the dense double-crosslinked film effectively restricted the diffusion of the water molecules, resulting in excellent slow-release properties fitting with the Korsmeyer-Peppas kinetic model. Especially, O-HACC/PA-g-DCS film, which had more reaction sites for Schiff base crosslinking than N-HACC, exhibited the equilibrium swelling ratio of 800 % at 60 h and could sustainably release nisin via non-Fickian diffusion behavior until 48 h. Moreover, the HACC/DCS-based double-crosslinked film performed good long-time antibacterial activity and preservation effects on salmon. On the 10th day of storage, the TVBN of N-HACC/PA-g-DCS and O-HACC/PA-g-DCS groups were only 28.26 ±â€¯1.93 and 29.06 ±â€¯1.68 mg/100 g and still lower than the thresholds.

Benzyl Isothiocyanate and Resveratrol Synergistically Alleviate Dextran Sulfate Sodium-Induced Colitis in Mice.

The aim of our study was to investigate whether the combination of benzyl isothiocyanate (BITC) and resveratrol (RES) has a synergistic effect on the inhibition of inflammation in colitis. The results revealed that the BITC and RES combination (BITC_RES) was more effective than either substance alone at significantly alleviating the symptoms of dextran sodium sulfate (DSS)-induced colitis in mice, including the prevention of colon shortening and loss of body weight, a reduction in the disease activity index, and prevention of colon damage. Similarly, compared with the DSS group, BITC_RES reduced myeloperoxidase (MPO) and inducible nitric oxide synthase (iNOS) levels in the mouse colon by 1.4-3.0-fold and 1.4-fold, respectively. In addition, the combination of BITC and RES upregulated the inflammatory factor IL-10 by 1.3- and 107.4-fold, respectively, compared to the individual BITC and RES groups, whereas the proinflammatory factors, including TNF-α, IL-1ß, and IL-6, were downregulated by 1.1-7.4-, 0.7-3.6-, and 0.6-2.6-fold, respectively, in the BITC_RES group compared with the individual groups. Gut microbiome analysis indicated that BITC_RES remodeled the structure of gut bacteria at the phylum, family, and genus levels, upregulating the abundance of the phylum Bacteroidetes and the family Muribaculaceae and the genus norank_f_Muribaculaceae and downregulating the abundance of the phylum Firmicutes. Significant correlations between the relative levels of these proinflammatory cytokines and changes in the gut microbiota were found using Pearson's correlation analysis. BITC and RES exhibited synergistic effects by reshaping the gut microbiota and modulating the level of serum cellular inflammatory factors, thus exerting a protective effect against colitis.

An antibacterial film using κ-carrageenan loaded with benzyl isothiocyanate nanoemulsion: Characterization and application in beef preservation.

Benzyl isothiocyanate (BITC) is a naturally active bacteriostatic substance and κ-carrageenan (KC) is a good film-forming substrate. In the present study, a nanoemulsion incorporating BITC was fabricated with a particle size of 224.1 nm and an encapsulation efficiency of 69.2 %. Subsequently, the acquired BITC nanoemulsion (BITC-NE) was incorporated into the KC-based film, and the light transmittance of the prepared composite films was lower than that of the pure KC film. Fourier transform infrared spectroscopy and scanning electron microscopy revealed that BITC-NE was compatible with the KC matrix. BITC-NE incorporation enhanced the tensile strength of the KC-based films by 33.7 %, decreased the elongation at break by 33.8 %, decreased the water vapor permeability by 60.1 %, increased the maximum thermal degradation temperature by 48.8 %, and decreased the oxygen permeability by 42 % (p < 0.05). Furthermore, the composite films showed enhanced antimicrobial activity against Staphylococcus aureus, Salmonella typhimurium, and Pseudomonas fluorescens. The developed KC-based composite films were applied to wrap raw beef, which significantly delayed the increase in total viable count, total volatile base nitrogen content, and thiobarbituric acid reactive substances, and prolonged the shelf-life of the raw beef by up to 10 days. These results indicated that the composite films prepared by incorporating BITC nanoemulsions into KC matrices have great antimicrobial application potential.

Transcriptomic and Molecular Docking Analysis Reveal Virulence Gene Regulation-Mediated Antibacterial Effects of Benzyl Isothiocyanate Against Staphylococcus aureus.

Staphylococcus aureus (S. aureus) is a common pathogen that can cause many serious infections. Thus, efficient and practical techniques to fight S. aureus are required. In this study, transcriptomics was used to evaluate changes in S. aureus following treatment with benzyl isothiocyanate (BITC) to determine its antibacterial action. The results revealed that the BITC at subinhibitory concentrations (1/8th MIC) treated group had 94 differentially expressed genes compared to the control group, with 52 downregulated genes. Moreover, STRING analyses were used to reveal the protein interactions encoded by 36 genes. Then, we verified three significant virulence genes by qRT-PCR, including capsular polysaccharide synthesis enzyme (cp8F), capsular polysaccharide biosynthesis protein (cp5D), and thermonuclease (nuc). Furthermore, molecular docking analysis was performed to investigate the action site of BITC with the encoded proteins of cp8F, cp5D, and nuc. The results showed that the docking fraction of BITC with selected proteins ranged from - 6.00 to - 6.60 kcal/mol, predicting the stability of these complexes. BITC forms hydrophobic, hydrogen-bonded, π-π conjugated interactions with amino acids TRP (130), GLY (10), ILE (406), LYS (368), TYR (192), and ARG (114) of these proteins. These findings will aid future research into the antibacterial effects of BITC against S. aureus.

In-situ growth of metal-organic frameworks on cellulose nanofiber aerogels for rapid adsorption of heterocyclic aromatic amines.

Heterocyclic aromatic amines (HAAs) are the main carcinogens produced during thermal processing of protein-rich foods. In this paper, a composite aerogel (TOCNFCa) with a stabilized dual-network structure was prepared via a template for the in-situ synthesis of UiO-66 on cellulose for the adsorption of HAAs in food. The dual-network structure of TOCNFCa provides the composite aerogel with excellent wet strength, maintaining excellent compressive properties. With the in-situ grown UiO-66 content up to 71.89 wt%, the hierarchical porosity endowed TOCNFCa@UiO-66 with the ability to rapidly adsorb HAAs molecules with high capacity (1.44-5.82 µmol/g). Based on excellent thermal stability, adsorption capacity and anti-interference, TOCNFCa@UiO-66 achieved satisfactory recoveries of HAAs in the boiled marinade, which is faster and more economical than the conventional SPE method. Moreover, TOCNFCa@UiO-66 could maintain 84.55 % of the initial adsorption capacity after 5 times of reuse.

Defective UiO-66/cellulose nanocomposite aerogel for the adsorption of heterocyclic aromatic amines.

Heterocyclic aromatic amines (HAAs), arising as chemical derivatives during the high-temperature culinary treatment of proteinaceous comestibles, exhibit notable carcinogenic potential. In this paper, a composite aerogel (AGD-UiO-66) with high-capacity and fast adsorption of HAAs was made with anchoring defective UiO-66 (D-UiO-66) mediated by lauric acid on the backbone of cellulose nanofibers (CNF). AGD-UiO-66 with hierarchical porosity reduced the mass transfer efficiency for the adsorption of HAAs and achieved high adsorption amount (0.84-1.05 µmol/g) and fast adsorption (15 min). The isothermal adsorption model demonstrated that AGD-UiO-66 belonged to a multilayer adsorption mechanism for HAAs. Furthermore, AGD-UiO-66 was successfully used to adsorb 12 HAAs in different food (roasted beef, roasted pork, roasted salmon and marinade) with high recoveries of 94.65%-104.43%. The intrinsic potential of AGD-UiO-66 demonstrated that it could be widely applicable to the adsorption of HAAs in foods.

AHL-differential quorum sensing regulation of amino acid metabolism in Hafnia alvei H4.

Quorum sensing (QS) regulation of functional metabolites is rarely reported but a common trait of some bacteria. In this study, we found that QS promoted the extracellular accumulation of glycine and serine while inhibiting the extracellular accumulation of methionine in Hafnia alvei H4. The correlation analysis of five QS signals with the above three QS-regulated amino acids suggested that these QS signals may have functional differences in amino acid regulation. The exogenous AHL add-back studies on genes involved in glycine, serine, and methionine metabolic pathway highlighted that N-octanoyl-l-homoserine lactone (C8-HSL) downregulated the expression of sdhC/fumA genes involved in the succinate to malate pathway, thereby reducing the metabolic flux of the tricarboxylic acid (TCA) cycle as an amino acid metabolism platform. Further in-depth research revealed that the QS system promoted the conversion of folate to tetrahydrofolate (THF) by positively regulating the expression of folA and folM, thus impairing the ability of folate to promote methionine accumulation. Moreover, folate positively regulated the expression of the QS signal synthesis gene luxI, promoting the synthesis of QS signals, which may further enhance the influence of the QS system on amino acid metabolism. These findings contribute to the understanding of amino acid metabolism regulated by QS and provide new perspectives for accurate control of metabolic regulation caused by QS.IMPORTANCEAs one of the important regulatory mechanisms of microorganisms, quorum sensing (QS) is involved in the regulation of various physiological activities. However, few studies on the regulation of amino acid metabolism by QS are available. This study demonstrated that the LuxI-type QS system of Hafnia alvei H4 was involved in the regulation of multiple amino acid metabolism, and different types of QS signals exhibited different roles in regulating amino acid metabolism. Additionally, the regulatory effects of the QS system on amino acid metabolism were investigated from two important cycles that influence the conversion of amino acids, including the TCA cycle and the folate cycle. These findings provide new ideas on the role of QS system in the regulation of amino acid metabolism in organisms.

Rapid and large-capacity adsorption of heterocyclic aromatic amines on heat resistant two-dimensional metal organic layer/cellulose nanofiber aerogels constructed by a thawing cross-linking strategy.

Composite aerogels, formed by the combination of nanoscale polymers and highly efficient adsorbents, offer the potential to deploy adsorbent distinct separation properties into a processable matrix. This paper presents a method for the fabrication of low energy bio-aerogels with high ductility, excellent wet strength and favorable heat resistance, based on cellulose nanofibers (CNFs) bound by calcium carbonate particles (CaCO3) via a simple process of ice induction, cross-linking during freezing and freeze-drying. Due to induced defects, two-dimensional metal-organic layers (MOLs) were rich in mesoporous structure and embedded in the aerogel (AGCa-MOL), which exhibited a powerful adsorption capacity. AGCa-MOL could take full advantage of their hierarchical pores and available surface area to obtain high adsorption capacity (0.694-5.470 µmol/g) and rapid adsorption kinetics (5 min) for 14 heterocyclic aromatic amines (HAAs). Moreover, the CaCO3 particles and MOLs gave the AGCa-MOL excellent thermal stability, so that it could maintain excellent adsorption capacity at a high temperature (100 °C) and be applied as an adsorbent to remove HAAs in the boiling marinade. The intrinsic potential of composite aerogels was revealed due to the synergistic properties of the various components in the composite aerogel.

The Preparation and Properties of Amino-Carboxymethyl Chitosan-Based Antibacterial Hydrogel Loaded with ε-Polylysine.

In this paper, amino-carboxymethyl chitosan (ACC) was prepared through amino carboxymethylation, which introduces -COOH and -NH2 groups to the chitosan (CS) chains. Meanwhile, dialdehyde starch (DAS) was produced by oxidizing corn starch using sodium periodate. To attain the optimal loading and long-time release of ε-polylysine (ε-PL), the ACC/DAS hydrogels were synthesized through the Schiff base reaction between the amino group on ACC and the aldehyde group in DAS. The molecular structure, microcosmic properties, loading capacity, and bacteriostatic properties of the four types of hydrogels containing different mass concentrations of ACC were investigated. The results showed that the dynamic imine bond C=N existed in the ACC/DAS hydrogels, which proved that the hydrogels were formed by the cross-linking of the Schiff base reaction. With the increasing mass concentration of the ACC, the cross-sectional morphology of the hydrogel became smoother, the thermal stability increased, and the swelling behavior was gradually enhanced. The tight network structure improved the ε-PL loading efficiency, with the highest value of 99.2%. Moreover, the loading of ε-PL gave the hydrogel good antibacterial properties. These results indicate that ACC/DAS hydrogel is potential in food preservation.

Potential quorum-sensing inhibitor of Hafnia alvei H4-theaflavin-3,3´-digallate analyzed by virtual screening and molecular simulation.

Hafnia species can cause food spoilage via the quorum-sensing (QS) system. Thus, strategies that target QS in these bacteria might be a good approach to safeguard the quality of processed food. In this study, the amino acid sequence of the LasI Ha protein, a key QS regulator from Hafnia alvei H4, was used to construct its 3D structure for the virtual screening of potential QS inhibitors (QSIs) from the Bioactive Compound database. Four potential QSIs were obtained, and these were all theaflavins (TFs). Among them, theaflavin-3,3´-digallate (TF3) was found to outperform the others, displaying a higher docking score according to molecular docking analysis, and required only a sub-minimal inhibitory concentration (31.25 mM) to cause a significant decrease in the production of the autoinducer N-acyl homoserine lactone in H. alvei H4 and up to 60.5% inhibition of its motility. Furthermore, molecular simulation results indicated that TF3 could stably bind to a cavity within LasI Ha to form stable hydrogen bonds and hydrophobic interactions with various key residues of the protein to exert the inhibitory effect. Thus, TF3 may be considered a potential compound to protect against food spoilage caused by H. alvei H4 via the quorum quenching. IMPORTANCE Hafnia alvei, the main strain studied in this paper, is often isolated from spoiled foods, especially refrigerated protein-based raw foods, and is generally considered to be a spoilage bacterium whose spoilage-causing properties may be closely related to its own very strong population-sensing activity, so the strategy of quorum quenching against H. alvei H4 may be a good way to guarantee the quality of processed foods. Given the current global requirements for food safety and quality, coupled with negative consumer perceptions of the excessive inclusion of synthetic chemicals in food products, the use of natural compounds as QSIs in the storage of aquatic food products would seem more attractive.

Amino carboxymethyl chitosan//dialdehyde starch/polyvinyl alcohol double-layer film loaded with ε-polylysine.

To develop food packaging with good antibacterial activity and mechanical performance, four amino carboxymethyl chitosan (ACC)//dialdehyde starch (DAS) /polyvinyl alcohol (PVA) films were prepared by Schiff base and hydrogen bond interactions for efficient loading and release of ε-polylysine (ε-PL). The effects of the Schiff base reaction on the physicochemical properties of the films were explored based on the different aldehyde group contents in DAS. The ACC//DAS4/PVA film exhibited a tensile strength of 62.5 MPa, and the water vapor and oxygen permeability was 8.77 × 10-3·g·mm/m2·d·kPa and 0.15 × 103·cm3·mm/m2·d, respectively. By leveraging the Schiff base reaction, the film swelling properties were improved by adjusting the cross-link density, mesh size, and molecular mass between the cross-links. The ACC//DAS4/PVA film could efficiently load ε-PL with a value of 98.44% and long-term release in a food simulant of 10% ethanol at 25 °C for 120 min. Moreover, the ACC-ε-PL//DAS4/PVA film was successfully used for salmon preservation.

Synergistic effects of benzyl isothiocyanate and resveratrol against Listeria monocytogenes and their application in chicken meat preservation.

This study aimed to investigate the synergistic effects of benzyl isothiocyanate (BITC) and resveratrol (RS) on Listeria monocytogenes and their application in chicken meat preservation. BITC combined with RS (BR) significantly enhanced the antimicrobial activity and inhibited the growth of Listeria monocytogenes within 24 h compared to individual treatment, as well as suppressing bacterial swimming and swarming motility, reducing biofilm formation by 56.4%, increasing cell membrane disruption, and inducing intracellular ROS surges. Synergistic effects were associated with the inhibition of biofilm formation, cell membrane destruction, and ROS production. Biofilm removal facilitated the direct antimicrobial action of BR. RS disrupted cell membrane permeability, allowing more BITC into the cells, resulting in increased intracellular antibacterial levels, cell membrane hyperpolarization, and rapid ROS accumulation. Furthermore, BR visibly slowed the microbial growth in chicken flesh stored at 25 °C and 4 °C. Therefore, BR is expected to be a new strategy for food preservation.

Functional Chitosan-Based Composite Film Incorporated with 3-(Methylthio) Propyl Isothiocyanate/α-Cyclodextrin Inclusion Complex for Chicken Meat Preservation.

The 3-(Methylthio) propyl isothiocyanate (MTPITC)-loaded inclusion complex prepared by α-cyclodextrin (α-CD) was incorporated into chitosan (CS) film to fabricate a packaging material for fresh chicken meat preservation. Scanning electron microscope images indicated homogenous dispersion of the MTPITC-α-CD in CS polymer. Fourier-transform infrared and X-ray diffraction techniques revealed that MTPITC-α-CD was incorporated into the CS film matrix by the physical interactions. The introduction of MTPITC-α-CD improved the UV-vis light-blocking ability, with a slight loss of transparency. Although the water solubility and water vapor barrier capacity were not significantly influenced by the addition of MTPITC-α-CD, the antioxidant attribute was significantly enhanced. The CS-MTPITC-α-CD film displayed obvious and sustained suppressive effects against Salmonella typhimurium, with the inhibition zone diameters of 14.7 mm at 12 h and 7.3 mm at 24 h, respectively. Moreover, the quality index analysis indicated that the CS-MTPITC-α-CD film-wrapped fresh chicken, during refrigerated storage, exhibited better preservative efficacy than the control groups, with the total viable counts of 6.5 Log CFU/g, total volatile base nitrogen of 8.4 mg/100 g, pH of 6.6, thiobarbituric acid-reactive substances of 0.2 mg/kg, and the sensory score of 5 at day 16. Collectively, these results suggest that CS-MTPITC-α-CD film is a prospective packaging candidate for delaying the quality deterioration of chicken meat.

Construction of an S-Scheme Ag2MoO4/ZnFe2O4 Nanofiber Heterojunction for Enhanced Photoelectrocatalytic Activity under Visible Light Irradiation.

The removal of organic dyes and pathogenic bacteria from contaminated water remains a significant challenge. In the present study, S-type heterojunction Ag2MoO4/ZnFe2O4 (AMO/ZFO) composite nanofibers were synthesized by electrospinning and co-precipitation and fabricated into photoanodes. It is found that the constructed S-type heterojunction of AMO/ZFO composites effectively inhibits the recombination of photogenerated carriers, in addition to the benefits of more exposed active sites and a greater specific surface area. When several properties are improved, AMO/ZFO composites exhibit excellent photoelectrocatalytic performance. The results demonstrate that under visible light irradiation, the photoelectrocatalytic degradation rate of AMO/ZFO-3 to methylene blue reached 76.2% within 50 min, and the killing rate of Salmonella was 83.6% within 80 min. The enhanced photoelectrocatalytic activity was due to the synergy of both electrochemical and photocatalytic effects. More importantly, after four testing cycles, AMO/ZFO-3 still has a better ability to kill pathogenic bacteria and degrade organic dyes due to its high stability. This work provides a feasible method for oxidizing organic dyes and pathogenic bacteria.

A Bioactive Chitosan-Based Film Enriched with Benzyl Isothiocyanate/α-Cyclodextrin Inclusion Complex and Its Application for Beef Preservation.

A bioactive packaging material based on chitosan (CS) incorporated with benzyl isothiocyanate (BITC) and α-cyclodextrin (α-CD) was fabricated to evaluate its preservative effects on fresh beef stored at 4 °C for 12 d according to the quality analysis. The Fourier-transform infrared (FTIR) spectrum revealed that the major structural moiety of BITC was embedded in the cavity of α-CD, except for the thiocyanate group. FTIR and X-ray diffraction analysis further verified that intermolecular interactions were formed between the BITC-α-CD and CS film matrix. The addition of BITC-α-CD decreased the UV light transmittance of pure CS film to lower than 63% but still had enough transparency for observing packaged items. The CS-based composite film displayed a sustainable antibacterial capacity and an enhanced antioxidant activity. Moreover, the total viable counts, total volatile base nitrogen, pH, thiobarbituric acid-reactive substances, and sensory evaluation of the raw beef treated with the CS-based composite film were 6.31 log colony-forming unit (CFU)/g, 19.60 mg/100 g, 6.84, 0.26 mg/kg, and 6.5 at 12 days, respectively, indicating the favorable protective efficacy on beef. These results suggested that the fabricated CS-based composite film has the application potential to be developed as a bioactive food packaging material, especially for beef preservation.

Dynamics of Bacterial Composition and Association with Quality Formation and Biogenic Amines Accumulation during Fish Sauce Spontaneous Fermentation.

High-throughput sequencing and high-pressure liquid chromatography (HPLC) methods were used to investigate the influences of microbial dynamics on the quality and biogenic amine (BA) content during fish sauce fermentation. The homogeneity of total viable bacteria and lactic acid bacteria in fish sauce becomes higher as fermentation progresses. Tetragenococcus was the key genus of fish sauce fermentation. Carnobacterium (38.43%) and Lentibacillus (41.01%) were the dominant genera in the samples fermented for 3 months and 18 months, respectively. These three bacterial genera were significantly related to the physicochemical characteristics and characteristic flavors of the sauces. Tetragenococcus was significantly positively correlated with nitrogen oxides, the main characteristic flavor components in fish sauce. The BA content in fish sauce fermentation increased from 106.88 to 376.03 mg/kg, and the content of histamine reached 115.30 mg/kg at the end of fermentation, indicating that fish sauce has health risks. About 66.67% of Lentibacillus isolates were able to produce a large amount of BA, suggesting that Lentibacillus was the key genus for BA accumulation in fish sauce fermentation. Research on reducing the content of BA in fish sauce by intervening with regard to the fermentation temperature showed that a safe fish sauce product could be obtained at the fermentation temperature of about 25°C. These results help us to understand the contribution of microbial community composition to fish sauce fermentation and provide a basis for improving the quality and safety of fermented fish sauce. IMPORTANCE Traditional fermentation of fish sauce is mainly carried out by complex microbial communities from raw anchovies and processing environments. However, it is still unclear how the environmental microbiota influences the quality and the safety of fish sauce products. Therefore, this study comprehensively explained the influence of microorganisms on the quality and safety of fish sauce during the fermentation process in terms of physicochemical characters, flavors, and BA. Additionally, the accumulation of BA in fish sauce fermentation was controlled by intervening in the fermentation temperature. This finding contributes to a deeper understanding of the role of environmental microbiota during fermentation and provides data support for improving the safety of fish sauce.

Quorum Sensing (QS)-regulated target predictions of Hafnia alvei H4 based on the joint application of genome and STRING database.

In this study, we sequenced and characterized the genome of H. alvei to grasp the genetic basis of its physiological activities, including QS, metabolism, virulence and antibiotic resistance, and then mapped these functional gene clusters obtained from KEGG pathways to the STRING database to predict the QS-regulated targets in these pathways. H. alvei was found to possess 63 QS-related genes, most of which were closely related to amino acid metabolism, especially methionine pathway, but were not directly related to carbon and energy metabolism. Furthermore, the adhesion gene clusters were closely relevant to the QS gene clusters as well as to the infection gene clusters, while only one node (KdsD) was predicted between the QS gene clusters and infection gene clusters, suggesting that QS might influence the infection by regulating adhesion. QS might confer cross-resistance to microorganisms not only by regulating the formation of biofilms but also by affecting the efflux of antibiotics. In addition, the interspecies and intraspecies patterns of absence/presence for QS and its target genes were determined to shed light on the conservation of the QS regulatory mechanism among the phylogenetically related species. Taken together, the proposed methodology could expand the spectrum of possible applications of genome-based analysis to decipher the basic metabolic relationship of a microorganism, especially when studying new isolates.

Hierarchical Porous Nanocellulose Aerogels Loaded with Metal-Organic Framework Particles for the Adsorption Application of Heterocyclic Aromatic Amines.

This work overcomes the long-standing challenge of cumbersome pretreatment methods in the detection of heterocyclic aromatic amines (HAAs). A UiO-66/nanocellulose composite aerogel (CMC-CNC-UiO-66) with layered pores and low density prepared by a self-cross-linking method is applied as a simple and rapid adsorbent for capturing 14 HAAs via strong electrostatic interactions, van der Waals force, and the steric effect. The adsorption capacity of CMC-CNC-UiO-66 to 14 HAAs reached 98.00-188.00 nmol/mg at equilibrium within 10 min. The adsorption and desorption abilities of CMC-CNC-UiO-66 were retained with values of 93.36 and 97.34% after two cycles. In the meantime, the kinetics study demonstrated the chemisorption between HAA molecules and CMC-CNC-UiO-66 due to the excellent agreement with the pseudo-second-order adsorption models. The fit with the Freundlich isotherm models suggested a multilayer adsorption mechanism between HAA molecules and materials with heterogeneous surfaces. Moreover, coupled with the ultrahigh-performance liquid chromatography-tandem mass spectrometry detection, the CMC-CNC-UiO-66 extraction process can be completed with a high average recovery ranging from 86.68 to 115.33%, indicating a potential application of CMC-CNC-UiO-66 in HAA adsorption for further quantitative analysis.

Superior acetone sensor based on hetero-interface of SnSe2/SnO2 quasi core shell nanoparticles for previewing diabetes.

To improve gas sensing performance of SnO2 sensor, a heterostructure constructed by SnO2 and SnSe2 is designed and synthesized via hydrothermal method and post thermal oxidation treatment. The obtained SnSe2/SnO2 composite nanoparticles demonstrate a special core-shell structure with SnO2 nanograins distributed in the shell and mixed SnSe2 and SnO2 nanograins in the core. Owning to the promoted charge transfer effect invited by SnSe2, the sensor based on SnSe2/SnO2 composite nanoparticles exhibit expressively enhanced acetone sensing performance compared to the pristine SnO2 sensor. At the working temperature of 300 °C, the SnSe2/SnO2 composite sensor with optimized composition exhibits superior sensing property towards acetone, including high response (10.77-100 ppm), low theoretical limit of detection (0.354 ppm), high selectivity and good reproducibility. Moreover, the sensor shows a satisfactory sensing performance in trace acetone gas detection under high humidity condition (relative humidity: 70-90%), making it a promising candidate to constructing exhaled breath sensors for acetone detection.

Preparation of chitosan-cellulose-benzyl isothiocyanate nanocomposite film for food packaging applications.

To improve the mechanical and barrier properties of cellulose and chitosan (CS) and to allow the application of volatile antibacterial benzyl isothiocyanate (BITC) in active packaging, a double-layer nanocomposite film was prepared. Cellulose nanofibers (CNF) were crosslinked with CS via genipin to build the substrate. Quaternized cellulose nanocrystals (QCNC) were synthesized for carrying BITC as the coating material. By the layer-by-layer self-assembly approach, CS-CNF/QCNC-BITC film was fabricated. This film possessed the tensile strength of 33.75 MPa, low permeabilities of oxygen (6.9 × 10-17 m3/s·m·Pa) and moisture (1.2 × 10-11 g/s·m·Pa), and good antibacterial activity with the inhibition zone diameters of 4.9, 4.2 and 2.7 cm against Escherichia coli, Salmonella typhimurium and Staphylococcus aureus. The total viable count, total volatile basic nitrogen and thiobarbituric acid-reactive substances of the chicken wrapped CS-CNF/QCNC-BITC were only 4.4 log CFU/g, 17.7 mg/100 g and 0.44 mg/kg at 14 days, indicating a potential application of CS-CNF/QCNC-BITC for food packaging.