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Polysaccharides are carbohydrate polymers that are major components of plants, animals, and microorganisms, with unique properties. Biological hydrogels are polymeric networks that imbibe and retain large amounts of water and are the major components of living organisms. The mechanical properties of hydrogels are critical for their functionality and applications. Since synthetic polymeric double-network (DN) hydrogels possess unique network structures with high and tunable mechanical properties, many natural functional polysaccharides have attracted increased attention due to their rich and convenient sources, unique chemical structure and chain conformation, inherently desirable cytocompatibility, biodegradability and environmental friendliness, diverse bioactivities, and rheological properties, which rationally make them prominent constituents in designing various strong and tough polysaccharide-based DN hydrogels over the past ten years. This review focuses on the latest developments of polysaccharide-based DN hydrogels to comprehend the relationship among the polysaccharide properties, inner strengthening mechanisms, and applications. The aim of this review is to provide an insightful mechanical interpretation of the design strategy of novel polysaccharide-based DN hydrogels and their applications by introducing the correlation between performance and composition. The mechanical behavior of DN hydrogels and the roles of varieties of marine, microbial, plant, and animal polysaccharides are emphatically explained.
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Hidrogéis , Polissacarídeos , Animais , Hidrogéis/química , Polissacarídeos/química , PolímerosRESUMO
A facile synthetic route was developed to prepare a surface-grafted brush layer of poly(vinyl ethers) (PVEs) directly by a radical mechanism, with the "naked" Li+ acting as a catalyst. Density functional theory calculations suggested that complexation of naked Li+ to VEs significantly reduced the highest unoccupied molecular orbital-lowest unoccupied molecular orbital (HOMO-LUMO) energy gap from 5.08 to 0.68 eV, providing a better prospect for electron transfer. The structure, morphology, and surface properties of grafted polymer layers were characterized using attenuated total reflection Fourier transform infrared spectroscopy, Raman spectroscopy, X-ray photoelectron spectroscopy, atomic force microscopy, and dynamic water contact angle (DCA). Moreover, ellipsometry data indicated that the thickness of the polymer brushes was in the range of 20-60 nm, which corresponds to the grafting densities of 0.65-1.15 chain/nm2, and DCA decreased from 84.4 to 45.3°. Most importantly, no hydrolysis was observed for the modified surface after 30 days of exposure to phosphate-buffered saline solution, 0.1 mol/L NaOH(eq) and 0.1 mol/L HCl(eq), demonstrating excellent hydrolysis resistance with long service life. In addition, as a proof of concept, the side hydroxyl groups of grafted PVEs provide active sites for efficient fixation of bioactive molecules, e.g., glycosaminoglycan and serum protein.
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BACKGROUND: Brucellosis is a severe zoonotic disease that is increasingly prevalent in north China. A study evaluating Brucella infection in blood donors was conducted at Kashi central blood station, Xinjiang, China. STUDY DESIGN AND METHODS: Four serologic and two molecular methods of detection of Brucella infection were used in plasma samples from blood donations collected from Kashi in northwest China, considered a brucellosis-endemic area. Blood donor samples collected in Shenzhen, southern China, a brucellosis-nonendemic area, were tested as a negative control group. RESULTS: In 3896 plasma samples collected from Kashi central blood station, 135 (3.5%) plasma samples were reactive by the Rose Bengal plate test (RBPT), and 120 (3.1%) of the 135 RBPT-reactive sample were also reactive with the standard tube agglutination test (SAT), respectively. All samples of the control group of 399 blood samples from Shenzhen blood center tested negative with RBPT and SAT. Of 135 seroreactive plasma samples, 39 (1.0%) reacted with B. melitensis membrane protein extracts by enzyme-linked immunosorbent assay and 25 were reactive to either rBP26 or rOMP31 by Western blot. Thirteen plasma samples and two follow-up blood samples were identified as carrying Brucellaâ DNA by quantitative polymerase chain reaction (PCR) and nested PCR. Overall 15 (1:300) Kashi blood donations were found positive by nucleic acid testing, confirmed specific by DNA sequencing. CONCLUSIONS: The data indicate a probable high rate of Brucella bacteremia, suggesting a potential risk of transfusion-transmitted brucellosis. Blood donation screening for Brucella infection may be considered in the high Brucella-endemic areas of China.
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Bacteriemia/epidemiologia , Doadores de Sangue/estatística & dados numéricos , Segurança do Sangue , Brucelose/epidemiologia , Doenças Endêmicas , Reação Transfusional , Adulto , Testes de Aglutinação , Anticorpos Antibacterianos/sangue , Bacteriemia/sangue , Bacteriemia/transmissão , Western Blotting , Brucella/imunologia , Brucella/isolamento & purificação , Brucelose/sangue , Brucelose/transmissão , China/epidemiologia , DNA Bacteriano/sangue , Ensaio de Imunoadsorção Enzimática , Feminino , Hepatite B/sangue , Hepatite B/epidemiologia , Antígenos de Superfície da Hepatite B/sangue , Humanos , Masculino , Programas de Rastreamento/métodos , Valor Preditivo dos Testes , Reação em Cadeia da Polimerase em Tempo Real , Risco , Rosa Bengala , Coloração e RotulagemRESUMO
HYPOTHESIS: Elucidation of the micro-mechanisms of sol-gel transition of gelling glucans with different glycosidic linkages is crucial for understanding their structure-property relationship and for various applications. Glucans with distinct molecular chain structures exhibit unique gelation behaviors. The disparate gelation phenomena observed in two methylated glucans, methylated (1,3)-ß-d-glucan of curdlan (MECD) and methylated (1,4)-ß-d-glucan of cellulose (MC), notwithstanding their equivalent degrees of substitution, are intricately linked to their unique molecular architectures and interactions between glucan and water. EXPERIMENTS: Density functional theory and molecular dynamics simulations focused on the electronic property distinctions between MECD and MC, alongside conformational variations during thermal gelation. Inline attenuated total reflection Fourier transform infrared spectroscopy tracked secondary structure alterations in MECD and MC. To corroborate the simulation results, additional analyses including circular dichroism, rheology, and micro-differential scanning calorimetry were performed. FINDINGS: Despite having similar thermally induced gel networks, MECD and MC display distinct physical gelation patterns and molecular-level conformational changes during gelation. The network of MC gel was formed via a "coil-to-ring" transition, followed by ring stacking. In contrast, the MECD gel comprised compact irregular helices accompanied by notable volume shrinkage. These variations in gelation behavior are ascribed to heightened hydrophobic interactions and diminished hydrogen bonding in both systems upon heating, resulting in gelation. These findings provide valuable insights into the microstructural changes during gelation and the thermo-gelation mechanisms of structurally similar polysaccharides.
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Géis , Simulação de Dinâmica Molecular , Géis/química , Metilação , Temperatura , beta-Glucanas/química , Glicosídeos/química , Teoria da Densidade Funcional , Glucanos/química , Celulose/químicaRESUMO
Circulating tumor cells (CTCs) are the seeds of distant metastases of malignant tumors and are associated with malignancy and risk of metastasis. However, tumor cells undergo epithelial-mesenchymal transition (EMT) during metastasis, leading to the emergence of different types of CTCs. Real-time dynamic molecular and functional typing of CTCs is necessary to precisely guide personalized treatment. Most CTC detection systems are based on epithelial markers that may fail to detect EMT CTCs. Therefore, it is clinically important to identify new markers of different CTC types. In this study, bioinformatics analysis and experimental assays showed that trophoblast cell surface antigen 2 (TROP2), a target molecule for advanced palliative treatment of triple-negative breast cancer (TNBC), was highly expressed in TNBC tissues and tumor cells. Furthermore, TROP2 can promote the migration and invasion of TNBC cells by upregulating EMT markers. The specificity and potential of TROP2 as an EMT-associated marker of TNBC CTCs were evaluated by flow cytometry, immunofluorescence, spiking experiments, and a well-established CTC assay. The results indicated that TROP2 is a potential novel CTC marker associated with EMT, providing a basis for more efficacious markers that encompass CTC heterogeneity in patients with TNBC.
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Soft tissues in nature are anchored on the load-bearing structures of creatures, such as tendons, ligaments, and cartilages. However, mimetic hydrogel coatings that combine the unique properties of hydrogels (e.g., in situ formability, stimulus-responsiveness, strength controllability, environmental friendliness, and small molecular encapsulation) with the superior properties of substrates such as high elastic modulus and high tensile strength still require further exploration to achieve an adequately comprehensive performance. Herein, we report an approach for fabricating hydrogel coatings using an injectable, tough, and thermoplastic κ-carrageenan (κ-car)/poly(N-acryloyl glycinamide (NAGA)-co-vinyl imidazole (VI)) supramolecular hydrogel (κ-car/PNV hydrogel) with temperature-controlled adhesion by adjusting the contact at the hydrogel-substrate interface. The κ-car/PNV hydrogel with a mass ratio of NAGA to VI of 9:1 shows a sol-gel transition temperature of 85 °C, a compressive strain of 99%, a tensile strain of 1045%, fast self-recovery, durability, and the adhesive ability to handle irregular substrates. Furthermore, this supramolecular hydrogel coating forms strips and panels with slide rheostat-based touch sensing, which is minimally affected by water evaporation. This work facilitates the fabrication and application of hydrogel coatings as touch sensing devices to combine functional supramolecular hydrogels, surface coatings, and ionotronics.
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To resolve the major obstacles of poor water solubility and few functional derivatives in the practical utilization of curdlan, we prepared highly soluble and thermal-responsively alkylated curdlan with different degrees of substitution (DS) via homogeneous reaction. The properties of these derivatives were investigated by rheology, inline attenuated total reflective-Fourier transform infrared spectroscopy, Raman and fluorescence spectroscopy, micro-differential scanning calorimetry, dynamic light scattering, and in vitro cytotoxicity assay. The newly developed methylated and ethylated curdlan can form thermal reversible heat-set hydrogels accompanied by volume shrinkage due to syneresis. Their gelation temperatures depend strongly on the DS, size of hydrophobic groups, and the order of the Hofmeister series salts added. Experimental results indicated that the gel network was induced by the enhanced hydrophobic interaction among macromolecular chains and weakened hydrogen bonding between the polymer and water on heating, leading to phase separation and gelation.
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Éteres , beta-Glucanas , beta-Glucanas/química , Reologia , Espectroscopia de Infravermelho com Transformada de Fourier , Hidrogéis , Água/químicaRESUMO
We have synthesized the hybrid supercapacitor electrode of Co3O4 nanoparticles on vertically aligned graphene nanosheets (VAGNs) supported by carbon fabric. The VAGN served as an excellent backbone together with the carbon fabric, enhancing composites to a high specific capacitance of 3480 F/g, approaching the theoretical value (3560 F/g). A highly flexible all-solid-state symmetric supercapacitor device was fabricated by two pieces of our Co3O4/VAGN/carbon fabric hybrid electrode. The device is suitable for different bending angles and delivers a high capacitance (580 F/g), good cycling ability (86.2% capacitance retention after 20â¯000 cycles), high energy density (80 Wh/kg), and high power density (20 kW/kg at 27 Wh/kg). These excellent electrochemical performances, as a result of the particular structure of VAGN and the flexibility of the carbon fabric, suggest that these composites have an enormous potential in energy application.
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In recent years, the number of cases of human brucellosis has been increasing by approximately 10% per year in China. Most cases were caused by Brucella melitensis through contacts with infected sheep, goats or their products. An attenuated B. melitensis vaccine M5-90 is currently used to vaccinate both animals in China. This vaccine has not been investigated for critical parameters such as immune response and its association with protective efficacy. In this study, humoral and cellular immune response to the periplasmic protein BP26 and the outer membrane protein OMP31 were evaluated in M5-90 vaccinated Chinese merino and Kazak sheep. Antibodies to BP26 or OMP31 were detected at low levels, and specific IFN-γ response was quantified. Strongly reactive peptides derived from BP26 and OMP31 identified five T-cell epitopes (BP26-6, -8, -11, -12 and OMP31-23) common to both sheep species, five species-specific epitopes (BP26-10, -18, -21 and -22 and OMP31-12) and four animal-specific epitopes (BP26-15, -23, OMP31-6 and -21), which stimulated specific IFN-γ response in vaccinated sheep. Among those T-cell epitopes, reactivity to BP26-18 and -21 epitopes was significantly associated with MHC-I B allele (P=0.024). However, a specific T-cell response induced by the M5-90 vaccine was relatively week and did not sustain long enough, which might be suppressed by rapid activation of T-regulatory (Treg) cells following vaccination. These findings provide an insight in designing a safer and more effective vaccine for use in animals and in humans.