Fluorescence and pectinase double-triggered chitosan/pectin/calcium propionate/curcumin-ß-cyclodextrin complex film for pork freshness monitoring and maintenance.

An intelligent and active food packaging film based on chitosan (CS), pectin (P), calcium propionate (CP), and curcumin-ß-cyclodextrin complex (Cur-ß-CD) was prepared. The CS/P/CP/Cur-ß-CD film exhibited improved hydrophobicity (74.78 ± 0.53°), water vapor (4.55 ± 0.16 × 10-11 g·(m·s·Pa)-1), and oxygen (1.50 ± 0.06 × 10-12 g·(m·s·Pa)-1) barrier properties, as well as antioxidant (72.34 ± 3.79 % for DPPH and 86.05 ± 0.14 % for ABTS) and antibacterial (79.41 ± 2.89 % for E. coli and 83.82 ± 3.96 % for S. aureus) activities. The release of CP and Cur could be triggered by pectinase, with their cumulative release reaching 92.62 ± 1.20 % and 42.24 ± 1.15 %, respectively. The CS/P/CP/Cur-ß-CD film showed delayed alterations in surface color, pH value, total volatile bases nitrogen, total viable counts, thiobarbituric acid reactive substance, hardness, and springiness of pork. Additionally, the fluorescence intensity of the film gradually decreased. In conclusion, we have developed a pH-responsive film with pectinase-triggered release function, providing a new concept for the design of multi-signal responsive intelligent food packaging.

Recyclable bactericidal packaging films for emperor banana preservation.

Food safety issues and food waste have always been hot topics of concern. This study aimed to develop a recyclable bactericidal packaging film that combines polylactic acid (PLA), graphitic carbon nitride (CN) and carbon nanotubes (CNT) to extend food shelf life. This film exhibited compactness and thermostability, as observed by scanning electron microscope and differential scanning calorimeter. The temperature of P/CN/CNT film could still reach 54 ± 4 °C after being used for 3 times. The film still has bactericidal activity on the 5th cycle use except for L. monocytogenes revealed by morphological characterization on bacteria. This film effectively extended the shelf life of banana to 7 days, as confirmed by measurements of hardness, pH value and total bacterial count of banana. This study provides a packaging film with recyclable bactericidal ability.

pH-responsive double-layer film based on chitosan/curcumin-ß-cyclodextrin complex/cinnamaldehyde and zein/alizarin for pork freshness monitoring and maintaining.

A pH-responsive double-layer film comprising chitosan (CS), zein (Z), curcumin-ß-cyclodextrin complex (Cur- ß-CD), alizarin (AL) and cinnamaldehyde (CIN) was developed to detect spoilage and prolong the shelf life of pork. The outer Z/AL is the colorimetric responsive and highly protective outer layer, while the CS/Cur- ß-CD/CIN is the fluorescence responsive and functional layer. The CS/Cur- ß-CD/CIN-Z/AL film demonstrated excellent barrier properties against oxygen (8.48 × 10-13 g (m s Pa)-1) and water (2.42 × 10-11 g (m s Pa)-1) primarily due to the polar interactions in the Z structure and its hydrophobic nature. The addition of AL and Cur provided the CS/Cur- ß-CD/CIN-Z/AL film with pH colorimetric and fluorescence response capabilities, respectively. Furthermore, the inclusion of Cur- ß-CD, CIN and AL significantly enhanced the film's antioxidant and antibacterial properties, with radical scavenging rates of 79.29 % (DPPH) and 89.84 % (ABTS), as well as antibacterial efficiencies of 96.2 % (S. aureus) and 85.78 % (E. coli). To test the effectiveness of the double-layer film, a freshness monitoring and maintenance experiment was conducted on pork stored at 4 °C for 8 days. Various parameters of pork, including surface color, pH value, total volatile bases nitrogen (TVB-N), total viable counts (TVC), thiobarbituric acid reactive substance (TBARS), hardness and springiness, were measured, along with the color and fluorescence intensity (FL) of the film. The shelf life of the pork was extended by at least 2 days compared to the control group, and the pork was considered inedible if ΔE ≥ 12 or FL intensity ≤ 2160. Overall, this food packaging film shows promise in simultaneously monitoring and maintaining the freshness of pork.

Silver nanoparticles deposited carbon microspheres nanozyme with enhanced peroxidase-like catalysis for colorimetric detection of Hg2+ in seafood.

Novel methods for high-performance detection of Hg2+ in seafood are critical for ensuring food safety and human health. Herein, Ag nanoparticles (Ag NPs) were successfully deposited on carbon microspheres (CMs) to form Ag NPs-CMs nanocomplex. The proposed Ag NPs-CMs could oxidize colorless 3,3',5,5'-tetramethylbenzidine (TMB) to blue oxidation state TMB (oxTMB) in the presence of hydrogen peroxide (H2O2) and had a significant UV-vis absorption peak at 652 nm. The excellent peroxidase-like activity was attributed to the increased electrostatic attraction of CMs and the catalytic synergistic effect. After adding Hg2+, the catalytic activity of Ag NPs-CMs was specifically enhanced and the Michaelis-Menten constant (Km) decreased from 0.067 to 0.052 mmol/L due to the formation of Ag-Hg amalgam which produced more superoxide anions (O2•-) and hydroxyl radicals (•OH). The linear response ranges for Hg2+ were 2~833 nmol/L and 2.5~40 µmol/L, with the low detection limit of 1.10 nmol/L. This method was applied to detect Hg2+ in seafood with satisfactory recoveries of 95.65~106.56%. A hydrogel kit was designed for portable detection of Hg2+, and the response range was 0.5~5 µmol/L. This work provides a reliable method for visual Hg2+ detection in seafood as well as a feasible strategy for the design of high-performance nanozymes.

Triple-function chitosan-based film for pork and shrimp packaging.

A film simultaneously with colorimetric, fluorescent and active functions was engineered using chitosan (CS) and polyvinyl alcohol (PVA) as the film matrix and curcumin-ß-cyclodextrin complex (Cur-ß-CD) as the indicator for freshness monitoring and maintaining of pork and shrimp. In addition to the efficacy of prolonging shelf life, the film's color could change from yellow to orange with ΔE > 5 and its fluorescence intensity could decrease during storage. The incorporation of PVA significantly enhanced the mechanical properties of CS film with tensile strength of 31.80 MPa and elongation at break of 127.22 %. The Cur-ß-CD improved the antioxidant and antibacterial properties, water contact angle (from 86.3° to 111.2°), water vapor permeability (from 3.28 × 10-10 g (m s Pa)-1 to 0.42 × 10-10 g (m s Pa)-1) and mechanical properties of CS/PVA film. These results show the potential of the film as promising alternatives for intelligent and active food packaging.

Prrx1 promotes resistance to temozolomide by upregulating ABCC1 and inducing vasculogenic mimicry in glioma.

Gliomas are the most common primary brain tumors with dismal prognoses. Temozolomide (TMZ), the frontline therapeutic agent for gliomas, has shown limited clinical benefit primarily due to the acquired chemoresistance. Although growing evidence has suggested that the multi-drug resistance phenotype and abnormal vascular microenvironment are responsible for the intrinsic and extrinsic TMZ resistance, the molecular mechanism of TMZ resistance remains to be elucidated. In this study, we found Paired-related homeobox 1 (Prrx1) was an independent prognostic factor for the efficacy of chemotherapy-based postoperative treatment. Silencing Prrx1 markedly enhanced the TMZ-induced cytotoxicity both in vitro and in vivo. We also demonstrated that Prrx1 increased the expression of ABCC1, a member of ATP-Binding Cassette (ABC) transporter protein family, through binding to the promoter region of ABCC1 gene and initiating its transcription. Silencing ABCC1 mitigated the TMZ resistance induced by Prrx1. Furthermore, Prrx1 facilitates the formation of vasculogenic mimicry (VM), a critical extrinsic mechanism for glioma TMZ resistance. Collectively, our findings supported the critical role of Prrx1 in TMZ resistance via intrinsic and extrinsic mechanism. Targeting Prrx1 might represent a feasible strategy to overcome therapeutic resistance in glioma.

Carbon dots@Cu metal-organic frameworks hybrids for ratiometric fluorescent determination of pesticide thiophanate-methyl.

A dual-emission fluorescent (FL) probe was constructed by coordinating Cu2+ of copper metal-organic frameworks (Cu-MOFs) with - COO- group of carbon dots (CDs) for pesticide thiophanate-methyl (TM) determination. TM was recognized by organic ligands (H2BDC and H2BDC-NH2) of Cu-MOFs via π stacking. Due to the higher affinity of Cu2+ to TM than ligands and CDs, TM chelated with Cu2+ to form TM-Cu complex. Thus coordination of Cu-MOFs was damaged and the ligands were released resulting in the FL intensity increase of Cu-MOFs (F430). And also CDs were released from CDs@Cu-MOFs hybrids and electron transfer from CDs to CuMOFs was inhibited, leading to the FL intensity increase of CDs (F600). The FL intensity ratio (F430/F600) showed a good linear relationship with TM concentrations of 0.0307-0.769 µmol L-1 with a limit of detection (LOD) of ~ 3.67 nmol L-1. The probe was successfully applied to detect TM in spiked food samples with satisfactory recoveries of 93.1-113%. Additionally, visual detection of TM was achieved according to the fluorescence color variation from blue to carmine, indicating promising application of CDs@Cu-MOFs probe.

A dual-function chitosan packaging film for simultaneously monitoring and maintaining pork freshness.

Exploring food packaging films simultaneously possess freshness monitoring and maintaining can effectively tackle food safety issues. Here, we constructed a chitosan/N-doped carbon dots (CS/N-CDs) film which can monitor the freshness of pork based on pH-mediated fluorescent sensing and extend the shelf life based on the antioxidant, antibacterial and UV shielding properties. The fluorescent intensity of CS/N-CDs films increased with the increase of pork pH from 5.77 to 6.84 which positively related to the change of TVB-N from 6.68 to 17.53 mg/100 g. CS/N-CDs films had a maintaining effect on pork freshness corroborated by the scavenging activity on DPPH and ABTS radicals and antibacterial efficiency and inhibition zones of S. aureus and E.coli, and the total viable count, a value, weight loss, hardness and springiness of pork. Cell viability and hemolytic activity assay proved that CS/N-CDs films was safe. A novel chitosan-based intelligent and active food packaging film was provided.

LncRNA NEAT1 Promotes Gastric Cancer Progression Through miR-17-5p/TGFßR2 Axis Up-Regulated Angiogenesis.

BACKGROUND: Long non-coding RNAs (lncRNAs) have been indicated to play critical roles in gastric cancer (GC) tumorigenesis and progression. However, their roles in GC remain to be further elucidated. METHODS: RT-qPCR and fluorescence in situ hybridzation (FISH) were conducted to detect the expression of lncRNA NEAT1 in GC tissues and cell lines. Gene Set Enrichment Analysis (GSEA) was performed to screen out potential phenotypes and pathways that NEAT1 may participate in. NEAT1-silenced AGS and MGC803 cells were constructed and a series of functional experiments to investigate the roles of NEAT1 in GC angiogenesis both in vitro and in vivo. RNA pull down and luciferase reporter assays were utilized to illustrate the mechanisms underlying the functions of NEAT1 in GC. RESULTS: We observed that NEAT1 was upregulated in most GC specimens and cell lines. NEAT1 high was correlated with poor prognosis of GC patients. In vitro experiments showed that NEAT1 promoted GC angiogenesis by enhancing proliferation, migration, and tube formation ability of endothelial cells. Mechanism researches revealed that NEAT1 could competitively sponge miR-17-5p which targeted TGFßR2 directly. Subsequently, activate TGFß/Smad pathway by following with upregulation of a series of classical proangiogenic factors especially VEGF. CONCLUSION: The study unveiled that the LncRNA NEAT1/miR-17-5p/TGFßR2 axis is a novel mechanism in GC angiogenesis. Disrupting this axis may be a potential strategy for GC treatment.

Size effect-inspired fabrication of konjac glucomannan/polycaprolactone fiber films for antibacterial food packaging.

The exploration of new methods to produce food packaging with excellent physicochemical and antibacterial properties is of great scientific and technological interest. Here, we successfully prepare the food packaging films that are composed of konjac glucomannan (KGM), poly(ε-caprolactone) (PCL) and silver nanoparticles (AgNPs) via microfluidic spinning technology (MST). The obtained fiber films (average fiber diameter: 7.8 ± 0.2 µm) exhibit excellent antibacterial activities against S. aureus (34 ± 0.71 mm) and E. coli (39 ± 5.66 mm), which is ascribed to the good swelling of KGM in KGM/PCL/AgNPs fiber films (SD: 37.86 ± 6.87%). Fourier transform infrared (FT-IR) spectroscopy and X-ray diffraction (XRD) are employed to study the interactions between polymers. Thermogravimetric analysis (TGA), derivative thermogravimetry (DTG), water vapor permeability (WVP), and mechanical property measurements are conducted to evaluate the thermal properties, hydrophilicity and mechanical performances of the films. The results show that the films are thermal stable and relatively hydrophobic (WVP: 5.8 × 10-6 ± 1.44 g/(m·h·kPa), WCA: 101.0°) as well as have terrific elongation at break (EB: 223.59 ± 98.14%), which is beneficial for food packaging. This strategy provides a facile and green pathway for the construction of promising antibacterial food packaging.

Microfluidic spinning of poly (methyl methacrylate)/konjac glucomannan active food packaging films based on hydrophilic/hydrophobic strategy.

Here, inspired by the hydrophilic/hydrophobic theory, a novel konjac glucomannan/poly (methyl methacrylate)/chlorogenic acid (KGM/PMMA/CGA) food packaging film was successfully fabricated via microfluidic spinning technology (MST). The results of fourier transform infrared spectroscopy and x-ray diffraction confirmed the formation of hydrogen bonds in the films, which lead to the enhanced mechanical properties. Thermogravimetric analysis and differential scanning calorimetry showed excellent thermal stability of the films. Water vapor permeability (1.47 × 10-5 ±â€¯0.11 g/(m⋅h⋅kPa)) and water contact angle (89.2°) measurement proved that the films were hydrophobic. The good swelling degree (85.18 ±â€¯15.65%) indicated film's potentials in releasing CGA. More importantly, KGM played a key role in the antibacterial activities against Staphylococcus aureus (8.5 ±â€¯3.5 mm) and Escherichia coli (6.5 ±â€¯2.1 mm) by utilizing its hydrophilicity. Thus, our present work may provide a new idea for constructing active food packaging films with significant performances based on hydrophilic/hydrophobic strategy.

Robust microfluidic construction of konjac glucomannan-based micro-films for active food packaging.

The objective of this study was to develop a novel active food packaging with high performance by using natural active compound. Here, a facile and green strategy was employed to construct the konjac glucomannan/polylactic acid/trans-cinnamic acid micro-films (KPTMF) via microfluidic spinning technology (MST). MST, a mild preparation approach, could remain the activities of natural compound during processing. Konjac glucomannan could drive the release of trans-cinnamic by using its hydrophilicity under our careful design. The results of fourier-transform infrared spectra and infrared images revealed that konjac glucomannan, polylactic acid, and trans-cinnamic acid had good compatibility through hydrogen bonds in the micro-films, which was consistent with the X-ray diffraction results. Also, the good swelling degree (81.36 ±â€¯5.79%) of KPTMF could promote the release of trans-cinnamic. Besides, the KPTMF had excellent mechanical properties (Tensile strength: 14.09 ±â€¯2.97 MPa, Elongation at break: 3.12 ±â€¯0.57%), thermal stabilities and hydrophobicity (Water vapor permeability: 4.81 × 10-6 g/(m·h·kPa), Water contact angle: 99.2°). The obtained micro-films with large specific surface areas exhibited great antibacterial activities against Staphylococcus aureus and Escherichia coli, which suggested the potential applications in active food packaging.

Physicochemical properties of degraded konjac glucomannan prepared by laser assisted with hydrogen peroxide.

The exploration of methods for degrading konjac glucomannan (KGM) is of great significant and technological interest. Here, laser at the power of 10 W was employed to degrade KGM. The laser degraded konjac glucomannan (LDK) was analyzed by viscosity, Rheology, Differential scanning calorimetry (DSC), Fourier transform infrared (FT-IR) spectroscopy and laser light scatter (LLS). The viscosity of the LDK decreased from 8.38 Pa·s to 2.26 Pa·s and the average molecular weight (Mw) decreased from 7.6 × 105 Da to 5.7 × 105 Da with a polydispersity index (PDI) of 1.166. FT-IR spectra and IR images of the LDK indicated that the breakage of glucosidic bonds occurred during laser irradiation. DSC results indicated that the thermal stability of KGM has improved slightly after degradation. In addition, the determination of 1,1-diphenyl-2-picrylhrazyl (DPPH) radical scavenging activity suggested that the antioxidant activity of the LDK improved versus KGM. This stratagem provides a new pathway for efficiently degrading KGM.

Facile fabrication of novel konjac glucomannan films with antibacterial properties via microfluidic spinning strategy.

The exploration of methods to produce biomaterials with antibacterial properties in ultra-small scales is of great scientific and technological interest. Here, we reported a microfluidic spinning approach to prepare a novel film combined with konjac glucomannan (KGM), polyvinylpyrrolidone (PVP), and epigallocatechin gallate (EGCG). The film was characterized by scanning electron microscopy, Fourier transform infrared spectroscopy, X-ray diffraction, and thermogravimetric analysis. This film was transparent, orderly, thermally stable, and uniform in size, with an average width less than 1 µm. Also, the film exhibited excellent antibacterial efficiency (97.1% against E. coli, 99.7% against S. aureus, 97.3% against S. enterica and 99.9% against B. subtilis) in our antibacterial test. In addition, the film promoted wound healing with the advanced development of neovascularization and hair follicles. This strategy provides a facile and green pathway for the construction of biomaterial films for medical applications.

Robust microfluidic construction of hybrid microfibers based on konjac glucomannan and their drug release performance.

The exploration of methods to produce a novel wound dressing with sustained drug release properties in ultrasmall scales is of great scientific and technological interest. Herein, we propose konjac glucomannan/polyvinylidene fluoride (KGM/PVDF) hybrid microfibers having hydrophilic and hydrophobic segments based on microfluidic-oriented core-sheath composite microfibers, where the KGM/PVDF hybrid microfibers are wrapped in situ in CH3OH. The morphology of KGM/PVDF microfibers is uniform, smooth, and crack-free. Enrofloxacin (Enro) is loaded onto the microfibers as a representative cargo to test their release performance. The KGM/PVDF/Enro microfibers show sustained drug release performance (13 days), excellent heat resistance, antibacterial activity and promotion of wound healing. This study is an avenue toward the microfluidic design of hydrophilic/hydrophobic hybrid microfibers as wound dressings, and it will guide the development of next-generation wound dressing.