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  • Effect of the linear aliphatic amine functionalization on in vitro transfection efficiency of chitosan nanoparticles
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-10
    Mehmet Koray Gök, Kamber Demir, Erdal Cevher, Saadet Özgümüş, Serhat Pabuccuoğlu

    The aim of this study is to prepare the long linear aliphatic amine pendant group-functionalized chitosan-based nanoparticulate gene carrier system with improved properties for the efficient transfection. The amine functionalized chitosan (MChi) was synthesized by using N-(2-hydroxyethyl)ethylenediamine (HE-EDA) and characterized for the first time. The nanoparticles of MChi (nMChi) were prepared by ionic gelation method, and their particle size, polydispersity (PDI), zeta potential (mV), gene binding capacity and cytotoxicity were determined. Green Fluorescent Protein circular plasmid DNA (pEGFN1) loaded nanoparticles (gnMChi) were used in the transfection studies. The results showed that nMChi with a particle size of 102.9 nm and zeta potential of 41.9 ± 5.63 mV was non-toxic, had high transfection efficiency in Human Embryonic Kidney 293 and Primary Ovine Fibroblast cell lines and would be used as an efficient gene carrier system.

    更新日期:2018-12-10
  • Nanocellulose-graphene composites: A promising nanomaterial for flexible supercapacitors
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-07
    Jinghao Xing, Peng Tao, Zhengmei Wu, Chuyue Xing, Xiaoping Liao, Shuangxi Nie

    With the increasing consumption of global fossil energy and environmental pollution, the development of green renewable energy and efficient energy storage technology become an urgent problem to solve. Supercapacitors have drawn a great interest for use in wearable electronic devices due to their portability and stable performance. The electrode is very important when preparing a high-performance flexible supercapacitor, which requires good electrochemical performance and flexibility. Graphene and nanocellulose are excellent flexible electrode material for supercapacitors, and nanocellulose is often used as a substrate material for electronic devices because of its good biodegradability, mechanical flexibility and chemical reactivity. In this work, the structure design and assembly method of the nanocellulose-graphene composite materials used for flexible supercapacitors are reviewed. The mechanical flexibility, specific capacitance, electrochemical performance, cyclic stability, renewability and biodegradability are taken into account, so as to evaluate the performance of the composite materials and to better assess the merits of this material with respect to real applications.

    更新日期:2018-12-08
  • Modular synthesis of non-charged and ionic xylan carbamate derivatives from xylan carbonates
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-07
    Lars Gabriel, Martin Gericke, Thomas Heinze

    Novel non-charged and ionic xylan carbamate (XC) derivatives were synthesized in a modular approach from xylan phenyl carbonate (XPC) as reactive intermediate. XPC with varying degrees of substitution (DS) from 0.5 to 1.9 were converted with different non-ionic primary and secondary amines in different molar ratio to obtain the corresponding XC with high conversion rates of up to 100%. In a similar way, ionic amines were employed for the aminolysis of XPC to obtain charged XC. The XC were characterized by NMR- and infrared spectroscopy. XPC proofed to be highly versatile building blocks for the preparation of ionic xylan derivatives. The type and amount of charged groups could be tuned efficiently. Moreover, high DS values of up to 1.4 for cationic- and 1.8 for anionic XC derivatives could be achieved, which is higher than reported previously for comparable ionic xylan derivatives that were prepared by “conventional” esterification and etherification reactions.

    更新日期:2018-12-08
  • Biomedical Applications of Chitosan Electrospun Nanofibers as a Green Polymer – Review
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-08
    Katayoon Kalantari, Amalina M. Afifi, Hossein Jahangirian, Thomas J. Webster

    This review outlines new developments in the biomedical applications of environmentally friendly ('green') chitosan and chitosan-blend electrospun nanofibers. In recent years, research in functionalized nanofibers has contributed to the development of new drug delivery systems and improved scaffolds for regenerative medicine, which is currently one of the most rapidly growing fields in all of the life sciences. Chitosan is a biopolymer with non-toxic, antibacterial, biodegradable and biocompatible properties. Due to these properties, they are widely applied for biomedical applications such as drug delivery, tissue engineering scaffolds, wound dressings, and antibacterial coatings. Electrospinning is a novel technique for chitosan nanofiber fabrication. These nanofibers can be used in unique applications in biomedical fields due to their high surface area and porosity. The present work reviews recent reports on the biomedical applications of chitosan-based nanofibers in detail.

    更新日期:2018-12-08
  • A novel environmentally friendly method in solid phase for in situ synthesis of chitosan-gold bionanocomposites with catalytic applications
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-06
    Sebastián Bonardd, César Saldías, Oscar Ramirez, Deodato Radić, Francisco J. Recio, Marcela Urzúa, Angel Leiva

    A novel method to obtain catalytic bio-nanocomposites based on chitosan containing different amounts of gold nanoparticles generated in situ is reported. The formation of gold nanoparticles takes place in solid phase assisted by a heating induced process. This method only involves the use of chitosan biopolymer and a gold salt precursor. Unlike other methods the addition of external reducing and stabilizing agents to generate gold nanoparticles, is not needed because these roles are played by chitosan. Therefore, the striking properties of chitosan (e.g., high functionality, biodegradability and biocompatibility) are profited, in order to design a facile and green route of synthesis. Additionally, the described method allows to vary the amount and size of the gold nanoparticles contained in the bio-nanocomposite by using different gold ion compositions and temperatures of heating process. Finally, the bio-nanocomposite performance as heterogeneous catalyst on the reduction of p-nitrophenol (4-NP) to p-aminophenol (4-AP) as a model system was assessed. The results showed a significant catalytic effect that increases as the content of gold nanoparticles in the bio-nanocomposite also increases.

    更新日期:2018-12-07
  • Sulfated polysaccharide JCS1S2 inhibits angiogenesis via targeting VEGFR2/VEGF and blocking VEGFR2/Erk/VEGF signaling
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-06
    Zheng Wang, Can Jin, Xueying Li, Kan Ding

    More and more evidences suggested that sulfated natural glycans had impact on angiogenesis. However, the molecular targets and functional mechanism of glycans are still vague. JCS1S2 was the sulfated mannoglucan featured with a backbone of 1, 4-linked β-Manp and 1, 4-linked α-Glcp with sulfation at C-6 of β-Manp and α-Glcp residues, respectively. The degree of substitution of this sulfated polysaccharide was 1.74 and its molecular weight was 56.2 kDa. We provided evidences that JCS1S2 could disrupt angiogenesis both in vitro and in vivo. This sulfated polysaccharide inhibited migration and tube formation of human microvascular endothelial cells (HMEC-1) whereas showed no effect on the cells proliferation. Further study uncovered that JCS1S2 bound to both VEGF (vascular endothelial growth factor) (KD value: 4.82 × 10-9) and VEGFR2 (Vascular Endothelial Growth Factor Receptor 2) (KD value: 1.50 × 10-7) to inactivate VEGFR2 phosphorylation. In addition, JCS1S2 blocked downstream signaling and impaired the expression of VEGF and its transcription factor AP-1 (Activator protein-1). These results demonstrated that JCS1S2 interrupted angiogenesis via blocking VEGF signaling transduction and could be a potential anti-angiogenetic agent for disease treatment.

    更新日期:2018-12-07
  • One-Step Green Synthesis of Antibacterial Silver Nanoparticles Embedded in Electrospun Cyclodextrin Nanofibers
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-06
    Asli Celebioglu, Fuat Topuz, Zehra Irem Yildiz, Tamer Uyar

    Antibacterial electrospun nanofibers based on cyclodextrin (CD) and silver nanoparticles (Ag-NPs) were produced by solution electrospinning from aqueous and DMF solutions using different Ag contents. CD molecules acted as the reducing agent and catalyzed the formation of Ag-NPs. The nanofibers with smaller diameters were observed for the fibers generated from DMF solutions than those produced from aqueous solutions. TEM and STEM analyses revealed the Ag-NPs (~2-5 nm depending on solvent-type and Ag loading) in nanofibers, while FTIR and surface enhanced Raman scattering (SERS) analyses showed the apparent frequency shift of OH stretching band and the enhancement of Raman bands of CD molecules with the incorporation of the Ag-NPs. The polycrystalline structure of the Ag-NPs was shown by XRD and SAED analyses over {111}, {200}, {220} and {311} planes. The nanofibers showed significant inhibition against the growth of Escherichia coli and Staphylococcus aureus owing to the antibacterial activity of the Ag-NPs.

    更新日期:2018-12-07
  • Self-assembled micelles based on N-octyl-N’-phthalyl-O-phosphoryl chitosan derivative as an effective oral carrier of paclitaxel
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-06
    Guowei Qu, Siyuan Hou, Ding Qu, Chunli Tian, Jingcheng Zhu, Lingjing Xue, Caoyun Ju, Can Zhang

    Herein, we describe a novel amphipathic chitosan derivative (N-octyl-N’-phthalyl-O-phosphoryl chitosan, abbreviated as OPPC) as an effective oral delivery platform for P-gp substrates, especially paclitaxel (PTX). OPPC could readily self-assemble into micelles, solubilize and encapsulate PTX into the hydrophobic inner core of OPPC with superior loading capacity to chitosan. PTX/OPPC micelles possessed improved intestinal epithelial permeability and oral bioavailability of PTX evaluated by in situ perfusion and pharmacokinetic studies. In vivo fluorescence imaging revealed enhanced stability and integrity of OPPC micelles in mice gastrointestine. Furthermore, cellular uptake studies revealed effective transport and accumulation of OPPC micelles loading PTX or rhodamine-123 into Caco-2 cells via clathrin/cavelin-mediated endocytosis and OPPC-mediated P-gp inhibition. Mechanistically, the inhibition of P-gp efflux pumps by OPPC resulted from the reduction of membrane fluidity and decreased P-gp ATPase activity. In summary, OPPC micelles may serve as an efficient and promising delivery system for enhancing oral bioavailability of P-gp substrates.

    更新日期:2018-12-07
  • Role of acemannan O-acetyl group on murine radioprotection
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-06
    Sumit Kumar, Raj Kumar

    Present study was designed to investigate the role of acemannan acetyl group in murine model under radiotherapy. Acemannan, extracted from Aloe vera gel, has molecular weight of 1.02 × 106 Da and mainly composed of mannose (84.9%), glucose (7.2%), and galactose (3.9%), with backbone of (1→4)-linked mannose/glucose. Acemannan (DS: 1.01) was over-acetylated and deacetylated to investigate the role of acetyl group. Acetylation enhances acemannan viscosity and thermal stability. Free radicals scavenging and Fenton reaction inhibition was mediated by acemannan acetyl and hydroxyl group respectively. Native or over-acetylated/deacetylated acemannan pre-treatment to mice has shown to reduce the γ-radiation-induced oxidative damage, and hematopoietic injuries by free radical scavenging and microphage activation to secrete pro-hematopoietic factors through TLR-4 respectively. Over-acetylated acemannan has stronger effects on immunomodulation/radioprotection. In summary, acemannan acetyl-group modulates immune system, while hydroxyl-group participate in free radical scavenging, and present finding can be employed in food and pharma industries for enhancing polysaccharide bioactivity.

    更新日期:2018-12-07
  • Stability of cationic and amphoteric derivatives of mannan from the yeast Candida albicans
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-05
    Alžbeta Čížová, Katarína Csomorová, Jozef Rychlý, Slavomír Bystrický

    Infection with Candida albicans can prove lethal in immuno-compromised patients. It is imperative to develop a vaccine against this common organism. The amphoteric derivatives of the mannan component of the Candida cell wall may present a prospective target for the development of such a vaccine; however, the radical processing by antigen-presenting cells of the immune system is not fully understood. In this work a set of tailor-made cationic and amphoteric derivatives of three different degrees of quaternization (DSQ 0.14–0.38) has been prepared by chemical modification of ultrasonically-treated mannan and three carboxymethylated mannan derivatives (DSCM 0.13–0.32). These were exposed to free-radical attack by OH, generated in situ by the Fenton reaction. Potential changes in composition, DSQ, and molar mass distribution due to free-radical degradation were monitored by elemental analysis, NMR and FTIR spectroscopies, and size exclusion chromatography. A protective effect of quaternization against OH degradation was found. Non-isothermal thermogravimetric analysis found that the thermal stability of this mannan was also improved by chemical modification.

    更新日期:2018-12-06
  • Bioinspired hydrogels: Quinone crosslinking reaction for chitin nanofibers with enhanced mechanical strength via surface deacetylation
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-05
    Chuchu Chen, Dagang Li, Hiroyuki Yano, Kentaro Abe

    Suffering weak mechanical properties, hydrogels are generally limited to be applied as load-bearing materials. Previously, we introduced methods to fabricate high-strength hydrogels using chitin nanofibers (ChNFs) under alkali or calcium chloride conditions. This work provides an alternative approach for the preparation of quinone-crosslinked ChNF-based hydrogels using amino groups, which inspired by the quinone hardening process during insect cuticle sclerotization. By increasing the number of amino groups on the chitin crystalline surface through deacetylation, the resulting surface-deacetylated chitin nanofiber (S-ChNF) transformed to a dark hydrogel when reacted in hydroquinone (HQ)/copper (Cu(II)) solutions. The results show that the S-ChNF-based hydrogel displayed almost 10-fold higher tensile strength than the ChNF-based hydrogel due to the extended crosslinking effect between quinone and amino groups. Given the natural sustainability of chitin and the demonstrated improved mechanical strength, this work offers a promising strategy to fabricate a bioinspired S-ChNF-based hydrogel for potential applications in bio-medical engineering fields.

    更新日期:2018-12-06
  • Construction of blood compatible chitin/graphene oxide composite aerogel beads for the adsorption of bilirubin
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-05
    Xi Song, Xiuhong Huang, Zhixiong Li, Zhentao Li, Keke Wu, Yanpeng Jiao, Changren Zhou

    Excess bilirubin in blood can provoke hepatic damage and related malfunctions. Hereby we designed and constructed a novel bilirubin adsorbent, called chitin/graphene oxide (Ch/GO) composite aerogel beads, for efficient, fast and safe removal for bilirubin. The Ch/GO aerogel beads were prepared from chitin and GO in a NaOH/urea aqueous solution, followed dried by supercritical carbon dioxide. The morphology, structure and properties of the Ch/GO composite aerogel beads were characterized by scanning electron microscopy (SEM), Brunauer-Emmett-Teller (BET), fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and compressive strength measurement. The results indicated that GO was successfully bound to chitin matrix with enhanced surface area, thermal stability and mechanical strength. The adsorption capacity of Ch/GO composite aerogel beads for bilirubin was examined by UV-Visible spectrophotometry. Moreover, batch adsorption results revealed that the Ch/GO composite aerogel beads showed excellent bilirubin adsorption capacity (484.1 ± 16.9 mg/g) and short adsorption equilibrium time (0.5 h) under optimized condition. Furthermore, the Ch/GO aerogel beads exhibited a lower hemolysis property and improved anticoagulant property. Hence, this work provided a new strategy to develop a novel blood compatible bilirubin adsorbent, which presented good application potential for bilirubin adsorption.

    更新日期:2018-12-06
  • Biomass and Waste Materials as Potential Sources of Nanocrystalline Cellulose: Comparative Review of Preparation Methods (2016 - Till date)
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-05
    Shweta Mishra, Prashant S. Kharkar, Anil M. Pethe

    Nanocrystalline cellulose (NCC) has gained much popularity over the last decade as a preferred nanomaterial in varied applications, despite its laborious industrial production and higher cost. Its production methods have undergone a great deal of metamorphosis lately. The main emphasis has been on the environment-friendly and green processes, in addition to the sustainable and renewable feedstock. Globally, the researchers have explored biomass and waste cellulosic materials as renewable sources for NCC extraction. Newer and/or improved process alternatives, e.g., ultrasonication, enzymatic hydrolysis and mechanical treatments have been applied successfully for producing high-quality material. Detailed investigations on optimizing the overall yield from cheaper feedstock have yielded obvious benefits. This is still work in progress. The present review majorly focuses on the advances made in the NCC preparation field from biomass and waste cellulosic materials in last three years (2016 - till date). Collaborative efforts between chemical engineers and research scientists are crucial for the success of this really amazing nanomaterial.

    更新日期:2018-12-06
  • Mineralized layered films of xanthan and chitosan stabilized by polysaccharide interactions: A promising material for bone tissue repair
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-05
    Aline E. Aguiar, Mariana de O. Silva, Andrea C.D. Rodas, Celso A. Bertran

    Mineralized films are interesting biomaterials to repair bone defects. They can be easily shaped into bone defect and be permeated by body fluids as well as allow cell proliferation. Xanthan and chitosan films mineralized with hydroxyapatite prepared and characterized in this work showed an improved film stability and controlled swelling degree when dipped in different pH buffers. The layer-by-layer technique used in the film's preparation associated with the behaviour at different pH allowed to explore separately each interaction – polysaccharide-polysaccharide and polysaccharide-ions. The entanglement between polysaccharides, the interaction of the oppositely charged polysaccharides ionic groups (amide for chitosan and carboxylate for xanthan) and the interaction with Ca2+ ions confers a pH-responsive behaviour to the films. The mineralization with in situ hydroxyapatite formation resulted in an additional stability in the mineral phase. It has lower crystallinity similar to bone mineral as confirmed by X-Ray diffractogram. The films that were dipped in calcium phosphate solution during their production had positive results with in vitro cell adhesion test using MG63 cells culture.

    更新日期:2018-12-05
  • Comparative study on the behaviour of Chitosan-Gelatin based Hydrogel and nanocomposite ion exchanger synthesized under microwave conditions towards photocatalytic removal of cationic dyes
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-04
    Kuljit Kaur, Rajeev Jindal

    The present work reports the comparison study of Chitosan-Gelatin based hydrogels with their nanocomposite ion exchangers synthesized under microwave conditions for the adsorption and photodegradation of the cationic dyes. In this report, the hydrogel based on Chitosan-Gelatin, more selective for anionic dyes is modified to nanocomposite ion exchanger by incorporating the zirconium (IV) selenophosphate to make it selective for cationic dyes. The nanocomposite was investigated with a tremendous hike in the degradation capacity (99% from 12%) of MB after being modified to nanocomposite ion exchanger. Adsorption process followed Langmuir adsorption (Qo = 10.46 mgg-1) and non linear PFO kinetic model with k1, qe (calculated), R2, RMSE = 0.011, 1.02 (mgg-1), 0.996, and 0.01709 respectively.

    更新日期:2018-12-04
  • Structural characterization of aerogels derived from enzymatically oxidized galactomannans of fenugreek, sesbania and guar gums
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-03
    Erika Ponzini, Antonino Natalello, Fabrizio Usai, Matthias Bechmann, Francesco Peri, Norbert Müller, Rita Grandori

    Aerogels are obtained by laccase/2,2,6,6-tetramethylpiperidin-1-yl)oxyl (TEMPO)-oxidation of galactomannans (GMs) from the leguminous plants fenugreek (Trigonella foenum-graecum), sesbania (Sesbania bispinosa) and guar (Cyamopsis tetragonolobus). GM oxidation in aqueous solutions causes a viscosity increase, resulting in structured and stable hydrogels. Upon lyophilization, water-insoluble aerogels are obtained, capable of water uptake up to several times their own weight. The materials derived from the three gums have been analyzed and compared. Chemical modifications have been studied by electrospray-ionization mass spectrometry (ESI-MS) and Fourier-transform infrared spectroscopy (FTIR). Polymer structure has been determined by liquid-state and semi-quantitative solid-state nuclear magnetic resonance (NMR) spectroscopy and chemical stability by incubation under variable conditions of pH, ionic strength and solvent nature. The results show that hydrogel formation is due to oxidation of primary hydroxyl groups to carbonyl and carboxyl groups and subsequent formation of hemiacetal and ester bonds. Fenugreek displays the highest stability, compared to guar and sesbania rehydrated aerogels. This feature could be interpreted by its higher degree of substitution (Gal:Man = 1:1) and consequent higher amount of galactose primary alcohols, leading to more extensive crosslinking.

    更新日期:2018-12-03
  • Effect of pulsed electric field on structural properties and digestibility of starches with different crystalline type in solid state
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-03
    Qian Li, Qiu-Yan Wu, Wei Jiang, Jian-Ya Qian, Liang Zhang, Mangang Wu, Sheng-Qi Rao, Chun-Sen Wu

    Effect of pulsed electric field (PEF) on the structural properties of representative starches with different crystalline type, wheat starch for type A, potato starch for type B, and pea starch for type C, were investigated with polarized light microscopy (PLM), X-ray diffractometry (XRD), attenuated total internal reflectance Fourier transform infrared (ATR-FTIR) spectroscopy, solid-state nuclear magnetic resonance (SSNMR) spectroscopy, small-angle X-ray scattering (SAXS), and gel penetration chromatography (GPC) to understand whether PEF could be applied directly in starchy foods. The results showed that PEF could change the structure of all three types of starch, especially potato starch; the birefringence, represented by Maltese cross in polarized microscopic observation changed slightly; XRD and SSNMR spectra demonstrated PEF did not change the crystalline type of starch granules. However, relative crystallinity variations happened at some points of electric field intensity (EFI). Increasing with the EFI, a bigger variation of R1045/1022 happened in potato starch than in wheat starch and pea starch, as illustrated by ATR-FTIR. Significant influences of PEF on the scatter structure and fractal dimension of self-similar structures were observed for wheat starch and potato starch, but not for pea starch. The GPC suggested that molecular weight distribution changed for all the three starches. And in vitro tests showed that PEF changed significantly (P < 0.05) the digestibility of starches, especially wheat starch and potato starch.

    更新日期:2018-12-03
  • Multi-scale assembly of hydrogels formed by highly branched arabinoxylans from Plantago ovata seed mucilage studied by USANS/SANS and rheology
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-02
    Long Yu, Gleb E. Yakubov, Elliot P. Gilbert, Kim Sewell, Allison M.L. van de Meene, Jason R. Stokes

    The structures of two hydrogels formed by purified brush-like polysaccharides from Plantago ovata seed mucilage have been characterised from the nanometre to micrometre scale by using a combination of SANS and USANS techniques. These two hydrogels have distinctly different melting and rheological properties, but the structure of their gel networks bears striking similarity as revealed by USANS/SANS experiments. Surprisingly, we find that the dramatic changes in the rheological properties induced by temperature or change in the solvent quality are accompanied by a small alteration of the network structure as inferred from scattering curves recorded above melting or in a chaotropic solvent (0.7 M KOD). These results suggest that, in contrast to most gel-forming polysaccharides for which gelation depends on a structural transition, the rheological properties of Plantago ovata mucilage gels are dependent on variations in intermolecular hydrogen bonding. By enzymatically cleaving off terminal arabinose residues from the side chains, we have demonstrated that composition of side-chains has a strong effect on intermolecular interactions, which, in turn, has a profound effect on rheological and structural properties of these unique polysaccharides.

    更新日期:2018-12-02
  • Flexible heteroionic calcium-magnesium alginate beads for controlled drug release
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-30
    Noelia M. Sanchez-Ballester, Ian Soulairol, Bernard Bataille, Tahmer Sharkawi

    In the present work heteroionic calcium-magnesium alginate beads have been prepared by ionotropic gelation using different Ca:Mg ratios. This simple and straightforward approach allowed the obtention of CaMg-alginate beads presenting different mechanical performance depending on the Mg:Ca ratio. The dynamic swelling behavior of the beads was investigated. Increase in the quantity of Mg2+ incorporated in the beads increased the rate of swelling at pH 1.2 and pH 7.2. Finally, the release of ibuprofen was investigated. It was found that increasing the Mg2+ present in the beads raised the drug release rate.

    更新日期:2018-12-01
  • Duffy binding-like 1α adhesin from Plasmodium falciparum recognizes ABH histo-blood group saccharide in a type specific manner
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-30
    Isadora A. Oliveira, Laércio Pol-Fachin, Sebastião T. de Carvalho, Roberto D. Lins, Thereza A. Soares, Ronaldo Mohana-Borges, Jorge L. Neves, Adriane R. Todeschini

    The ability of erythrocytes, infected by Plasmodium falciparum, to adhere to endothelial cells (cytoadherence) and to capture uninfected erythrocyte (rosetting) is the leading cause of death by severe malaria. Evidences link the binding of the adhesin Duffy Binding Like1-α (DBL1α) domain to the ABH histo-blood antigens with formation of rosettes. Inspired by this very close relationship between the disease susceptibility and individual blood type, here we investigate the structural requirements involved in the interaction of DBL1α with A, B and H histo-blood determinants and their subtypes. Our results evidence the high preference of DBL1α to A epitopes, in comparison to B and H epitopes. DBL1α interacts with ABH epitopes in subtype specific manner, presenting a remarkable affinity for type 2 structures, Fucα1-2Galβ1-4GlcNAcβ1, particularly the A2 epitope. The contacts made by DBL1α binding pocket and the ABH histo-blood groups were mapped by theoretical methods and supported by NMR experiments.

    更新日期:2018-12-01
  • Exopolysaccharides of lactic acid bacteria: structure, bioactivity and associations: A review
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-30
    Yang Zhou, Yanhua Cui, Xiaojun Qu

    The ability to exhibit various bioactivities is widespread in exopolysaccharide (EPS) of lactic acid bacteria (LAB), and it has been admittedly associated with large structural variability of these polymers. Exceptional bioactivities such as cholesterol-lowering, immunomodulating, antioxidant, antiviral and anticoagulant effects render these biopolymers vast commercial value for global market and application potentials in medicine sector. Therefore, an elaborate understanding of structure-to-function associations will be prerequisite to search natural and artificial EPSs for new applications in functional food, health and medicine fields. In this review, it is presented a significant overview of the latest advances in the field of EPS from genes to application. This review emphasized in the general biosynthesis pathway together with genetic modules, multiple structures, functions, and respective functional mechanisms of LAB-derived EPSs, and the relationships between their structure and bioactivity, which will help to exploit new bioactive drugs from LAB-derived EPS.

    更新日期:2018-12-01
  • Mechanical, rheological and structural properties of fiber-containing microgels based on whey protein and alginate
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-30
    Alicia Magaly Leon, José M. Aguilera, Dong J. Park

    Dietary fiber (DF) - inulin (IN), bacterial cellulose nanofibers (BC), crystalline cellulose (CC) and oat fiber (OF) – were added at a concentration of 5% (2.5% for OF) to a whey protein isolate (WPI)/sodium alginate (NaAlg) dispersion. Gel microparticles (GMP) were formed by cold gelation followed by mechanical shearing. Compression stress-strain curves of bulk gels were similar for GMP-CC and GMP-OF but different from GMP-IN and GMP-BC. The soluble fiber IN did not change the aggregated matrix of the parent WPI/NaAlg gel, while other sources of DF became incorporated into the microgel matrix. Rheological tests (20 °C) revealed that GMP with added DF had a predominantly elastic behavior. Texture profile analysis suggested that GMP and GMP-IN had advantages over a commercial thickener in terms of adhesiveness and cohesiveness. GMP with added DF may find applications in foods for the elderly as texturizer and/or a carrier of fiber.

    更新日期:2018-12-01
  • Structural characteristics and hepatoprotective potential of Aralia elata root bark polysaccharides and their effects on SCFAs produced by intestinal flora metabolism
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-12-01
    Yong-Gang Xia, Tian-Long Wang, Si-Miao Yu, Jun Liang, Hai-Xue Kuang

    The structural characteristics of the polysaccharides from Aralia elata root barks (AERP) were systematically investigated by FT-IR, HPSEC-ELSD and colorimetric methods as well as by GC-MS based monosaccharide compositions, Smith degradations, and methylation analysis. The result showed average molecular weights of AERP were between 42.7 kDa and 93.9 kDa. AERP was composed of Ara, Rha, GlcA, Man, Glc, and Gal in a molar ratio of 22.2: 10.3: 8.1: 32.7: 5.7: 21.2 along with a small number of sulfate (3.38%) and acetyl (4.87%) groups. The abundant glycosidic linkages of Man, Ara, Gal, and Rha were observed as more than 90% of all the monosaccharides detected. Studies to evaluate hepatoprotective potentials of AERP showed that they had potent hepatoprotective effects in vivo in carbon tetrachloride-induced acute liver injury (CIALI) in mice by histopathological evaluation, biochemical examinations and ELISA assays. GC-MS was further used to determine the effects of AERP on the chemical profiles of nine common short-chain fatty acids (SCFAs) produced by intestinal flora metabolism in CIALI mice. These findings not only provide novel insights into the pharmacological actions of AERP on the protection from CIALI in mice, but they also demonstrate that determining SCFA profiles by targeted GC-MS metabolomics is an effective technique to investigate the molecular mechanisms of the effects of plant polysaccharides on intestinal flora metabolism.

    更新日期:2018-12-01
  • Extraction and characterization of dextran from Leuconostoc pseudomesenteroides YB-2 isolated from mango juice
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-29
    Guangbin Ye, Genliang Li, Changli Wang, Bo Ling, Ruirui Yang, Suoyi Huang

    An exopolysaccharide (EPS)-producing strain of YB-2 isolated from mango juice was identified as Leuconostoc pseudomesenteroides. The molecular weight (Mw) of this EPS was 7.67×105 Da. Gas chromatography (GC) analysis confirmed the presence of only glucose monomers. Fourier transform infrared (FT-IR) spectroscopy and nuclear magnetic resonance (NMR) spectra displayed the glucan nature of the EPS with 96.8% α-(1→6) and 3.2% branching α-(1→3) linkages. Scanning electron microscopy (SEM) showed smooth surfaces and compact structure. The water solubility index (WSI) and water-holding capacity (WHC) of dextran were 97.48±2.46% and 287.51±7.93%, respectively. The rheological analysis of dextran elucidated a non-Newtonian pseudoplastic behavior. The dextran revealed an inhibitory activity against Escherichia coli and Staphylococcus aureus with minimal inhibitory concentrations (MIC) of 2.0 mg/mL and 3.0 mg/mL, respectively.

    更新日期:2018-11-30
  • Catalytic and ionic cross-linking actions of L-glutamate salt for the modification of cellulose by 1,2,3,4-butanetetracarboxylic acid
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-29
    Bolin Ji, Peixin Tang, Chunyan Hu, Kelu Yan

    The sodium L-glutamate is reported as an efficient catalyst for the cross-linking between 1,2,3,4-butanetetracarboxylic acid (BTCA) and cellulose. Results presented ester absorbance of the treated fabrics strongly increased in the presence of the homemade L-glutamate salt, a mixture of L-glutamic acid (LGA) and NaOH at a specific ratio. Importantly, anti-wrinkle properties of the treated fabrics were significantly improved. Based on the relative concentration calculation, L-glutamate promoted the reaction of BTCA with cellulose by accelerating the formation of BTCA anhydrides and the esterification of anhydrides with cellulose. Besides, the improved anti-wrinkle property was partially attributed to the fact that the generated LGA reacted with cellulose and formed ionic cross-linking networks through amino groups with carboxyl groups in BTCA, which was confirmed by the Fourier transform infrared spectra and the computational calculations. Through detailed comparisons, L-glutamate catalyzed fabrics showed as good durability as sodium hypophosphite, indicating a possible alternative for phosphorus-containing catalysts.

    更新日期:2018-11-30
  • A facile slow-gel method for bulk Al-doped carboxymethyl cellulose aerogels with excellent flame retardancy
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-29
    Wenbin Hu, Lingbin Lu, Zhanying Li, Lin Shao

    Bulk Al-doped carboxymethyl cellulose aerogels were obtained via a facile slow-gel method and freeze-drying technology. In this method, the cross-linker Al3+ was released slowly and completely with enough D-(+)-gluconic acid δ-lactone as a sustained-release agent. Depended on controlled releasing of Al3+, the reaction speed between Al3+ and carboxyl groups was controlled and Al3+ was well-distributed in the aerogels. The coordination type between Al3+ and carboxymethyl cellulose was the bidentate bridging coordination. By adjusting the amount of Al3+ and the degree of substitution of carboxymethyl cellulose, interconnected network and closely packed sheet-like structure presented, respectively. According to the nitrogen adsorption-desorption isotherms, the aerogels were a kind of mesoporous material with pore blocking or cavitation. In addition, the aerogels exhibited outstanding weight-bearing capacity and excellent flame retardancy. This work provided a valuable reference for doping metal ions into polysaccharide aerogels and expanding the application fields of aerogels.

    更新日期:2018-11-30
  • N-oxy lipid-based click chemistry for orthogonal coupling of mannan onto nanoliposomes prepared by microfluidic mixing: synthesis of lipids, characterisation of mannan-coated nanoliposomes and in vitro stimulation of dendritic cells
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-29
    Eliška Bartheldyová, Pavlína Turánek Knotigová, Kateřina Zachová, Josef Mašek, Pavel Kulich, Roman Effenberg, Daniel Zyka, František Hubatka, Jan Kotouček, Hana Čelechovská, Renata Héžová, Andrea Tomečková, Eliška Mašková, Martina Fojtíková, Stuart Macaulay, Peter Bystrický, Lucia Paulovičová, Ema Paulovičová, Jaroslav Turánek

    New synthetic aminooxy lipid was designed and synthesized as a building block for the formulation of functionalised nanoliposomes (presenting onto the outer surface of aminooxy groups) by microfluidic mixing. Orthogonal binding of cellular mannan (Candida glabrata (CCY 26-20-1) onto the outer surface of functionalised nanoliposomes was modified by orthogonal binding of reducing termini of mannans to oxime lipids via a click chemistry reaction based on aminooxy coupling (oxime ligation). The aminooxy lipid was proved as a suitable active component for preparation of functionalised nanoliposomes by the microfluidic mixing method performed with the instrument NanoAssemblr™. This “on-chip technology” can be easily scaled-up. The structure of mannan-liposomes was visualized by transmission and scanning electron microscopy, including immunogold staining of recombinant mannan receptor bound onto mannosylated-liposomes. The observed structures are in a good correlation with data obtained by DLS, NTA, and TPRS methods. In vitro experiments on human and mouse dendritic cells demonstrate selective internalization of fluorochrome-labelled mannan-liposomes and their ability to stimulate DC comparable to lipopolysaccharide. We describe a potentially new drug delivery platform for mannan receptor-targeted antimicrobial drugs as well as for immunotherapeutics. Furthermore, the platform based on mannans bound orthogonally onto the surface of nanoliposomes represents a self-adjuvanted carrier for construction of liposome-based recombinant vaccines for both systemic and mucosal routes of administration.

    更新日期:2018-11-30
  • Controlled graft polymerization on the surface of filter paper via enzyme-initiated RAFT polymerization
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-30
    Wenyan Wang, Yu Yuanyuan, Ping Wang, Qiang Wang, Yongqiang Li, Jiugang Yuan, Xuerong Fan

    This study reports on eco-friendly graft polymerization approach for the modification of a cellulosic material via combination between enzymatic catalysis and reversible addition-fragmentation chain transfer polymerization (RAFT). Polyacrylamide (PAM) was polymerized on a cellulosic filter paper via horseradish peroxidase (HRP)-initiated RAFT polymerization. The results of grafting ratio, conversion, and pseudo-first-order kinetics were proved that the PAM graft polymerization on the filter paper followed RAFT rules. The results of Attenuated total reflection (ATR-FTIR), elemental analysis, and X-ray photoelectron spectroscopy (XPS) confirmed the presence of PAM in PAM-grafted filter paper. The results of water contact angle and Thermogravimetric analysis (TG) evidenced the change in the wetting properties and thermal performance, respectively of the treated filter paper. This work provides a new environmentally approach to graft polymerization on cellulosic materials.

    更新日期:2018-11-30
  • Rheological and morphological characterization of the culture broth during exopolysaccharide production by Enterobacter sp.
    Carbohydr. Polym. (IF 5.158) Pub Date : 2009-09-15
    Vítor D. Alves, Filomena Freitas, Cristiana A.V. Torres, Madalena Cruz, Rodolfo Marques, Christian Grandfils, M.P. Gonçalves, Rui Oliveira, Maria A.M. Reis

    Enterobacter sp. was grown on glycerol byproduct from the biodiesel industry for the production of a value-added exopolysaccharide (EPS). The culture broth was characterized in terms of its morphological and rheological properties throughout the cultivation run. Microscopic observations revealed the formation of cell aggregates surrounded by the EPS at the beginning of the cultivation run, while, at the end, aggregates were reduced and an EPS matrix with the cells embedded in it was observed. The apparent viscosity of the culture broth increased over time, which was attributed to the increase of the EPS concentration in the first period of the cultivation run. However, in the final stage, the creation of new polymer interactions within the complex culture broth was likely the reason for the viscosity increase observed, since there was not a significant variation of the EPS concentration, average molecular weight or chemical composition. The broth presented a Newtonian behavior at the beginning of the run, changing to pseudoplastic as the EPS concentration increased, and revealed to follow the Cox–Merz rule.

    更新日期:2018-11-29
  • Ultralight, hydrophobic, monolithic konjac glucomannan-silica composite aerogel with thermal insulation and mechanical properties
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-28
    Jundong Zhu, Jiang Hu, Chongwen Jiang, Siyuan Liu, Ying Li

    Konjac glucomannan (KGM) aerogel was prepared by a facile freeze-drying process, which was used as green sustainable biopolymer matrix to synthesis three-dimensional (3D) network interpenetrated KGM-SiO2 aerogel with thermal insulation performance and high mechanical properties. Herein, we explored that the potential structure–performance relationship of KGM aerogel between the physical parameters, morphology and thermal insulation. Besides, the preparation conditions of KGM aerogel including concentration of KGM, Na2CO3-to-KGM mass ratio were investigated. Meanwhile, the KGM aerogel and KGM-SiO2 aerogel were characterized using scanning electron microscopy, Fourier transform infrared spectrometer, Brunauer-Emmett-Teller method, thermogravimetric analysis and contact angle test. Results showed that the as-prepared KGM aerogel exhibited excellent thermal insulation performance (λ = 0.021 W m-1 K-1) and low bulk density (ρ = 0.030 g cm-3) when concentration of KGM was 2 wt% and Na2CO3-to-KGM mass ratio of 0.12. In order to improve the mechanical properties and high hydrophobicity of biopolymer aerogel, a novel of KGM-SiO2 aerogel was successful fabricated by incorporating methylsilsesquioxane (MTES) derived SiO2 into the KGM matrix via the freeze-drying method. The obtained aerogel exhibited remarkable compressive strength (δmax = 1.65 MPa at 80% strain), high specific surface area of 416.1 m2 g−1, high hydrophobicity (θ = 146° for water) and low thermal conductivity of 0.032-0.039 W m-1 K-1. Thus, the high-performance KGM-SiO2 aerogel would be further expand the thermal insulation application in sustainable development and energy-saving building.

    更新日期:2018-11-28
  • Production of magnetic chitinous microcages from ephippia of zooplankton Daphnia longispina and heavy metal removal studies
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-28
    Idris Sargin, Gulsin Arslan, Murat Kaya

    This is the first study on production of three dimensional chitinous microcages from ephippial eggs of a microcrustacean, Daphnia longispina (water flea) by keeping the original shape of its chitinous structure. Iron-based magnetic particles were successfully loaded into the chitinous microcages to enhance its heavy metal sorption capacity. The FT-IR, SEM-EDX and TGA analysis proved the purity of chitin and demonstrated that the loading of magnetic particles into the chitinous microcages was achieved. These newly obtained three-dimensional chitin microcages and magnetic particles loaded microcages were tested in Cd(II), Cr(III), Cu(II), Ni(II) and Zn(II) removal from aqueous solutions. Magnetic particles loaded microcages exhibited a better performance in removal of Cd(II), Cu(II) and Ni(II) ions; while unloaded microcages showed a higher affinity for Cr(III) and Zn(II). This study demonstrated that the chitin microcages are suitable carriers for iron-based magnetic particles. Here these new materials were studied only for removal of five heavy metal ions but these promising materials have a potential to be used in various fields.

    更新日期:2018-11-28
  • Chicken leg bone as a source of chondroitin sulfate
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-28
    Xiaojun Wang, Qingshan Shen, Chunhui Zhang, Wei Jia, Ling Han, Qunli Yu

    In this work, chondroitin sulfate (CS) was extracted from chicken leg bone soup using the heat-resin static adsorption extraction (HSAE) method. The HSAE method was optimized as follows: resin dosage, 10%; adsorption time, 4.3 h; eluent concentration, 2 M; eluent time, 1.3 h, under which the yield of CS1 from the bone soup reached 0.14% and the recovery rate was 67.35%. CS2, as reference, was obtained from the ends of chicken leg bone using enzymatic method. CS1 and CS2, together with other glycosaminoglycans, were confirmed using agarose-gel electrophoresis. The average molecular weight of CS1 and CS2 was 35.81 kDa and 37.18 kDa, respectively. The structures of CS1 and CS2 were compared using Fourier-transform infrared spectroscopy and high-performance liquid chromatography, and no significant difference was observed. Overall, the HSAE method was proposed to be a promising approach for the coproduction of CS and bone soup.

    更新日期:2018-11-28
  • In vitro immunomodulatory effects of human milk oligosaccharides on murine macrophage RAW264.7 cells
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-28
    Weiyue Zhang, Jingyu Yan, Lehao Wu, Yang Yu, Richard D Ye, Yan Zhang, Xinmiao Liang

    Human milk plays an important role in the child’s immune system. The human milk oligosaccharides (HMOs) may affect breast-fed infants both locally and systemically. In the present study, HMOs were separated, characterized and investigated for the immunomodulatory effects on RAW264.7 macrophages and its underlying molecular mechanisms. Our results revealed that HMO-7, one of the neutral HMOs fractions can significantly induce the production of nitric oxide (NO) and PGE2 via up-regulating nitric oxide synthase (iNOS) and cyclooxygenase 2 (COX-2) expression. Additionally, HMO-7 was found to stimulate the release of ROS, TNF-α and cytokines including IL-1β, IL-2, IL-6 and IL-10 in RAW264.7 macrophages. Further study showed that macrophage activated by HMO-7 involved in nuclear factor (NF)-κB and mitogen-activated protein kinase (MAPK) signaling pathways. Our study provides additional evidence that HMOs are the functional components in human milk and that HMOs may have the potential application in healthcare industry.

    更新日期:2018-11-28
  • Behaviour of citrus pectin during its gastrointestinal digestion and fermentation in a dynamic simulator (simgi®)
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-28
    Alvaro Ferreira-Lazarte, F. Javier Moreno, Carolina Cueva, Irene Gil-Sánchez, Mar Villamiel

    The behaviour of citrus pectin during digestion and its potential prebiotic properties were examined using a Dynamic Gastrointestinal Simulator (simgi®) model for the human gut, which simulates processes in the stomach, small intestine, ascending, transverse and descending colon. A remarkable non-digestibility of pectin in the upper gastrointestinal tract was observed by HPLC-ELSD analysis, where ~88% of citrus pectin remained intact during its transit through the stomach and small intestine. Fermentation of pectin stimulated the growth of beneficial bacteria such as Bifidobacterium spp, Bacteroides spp and Faecalobacterium prausnitzii. High increases of short-chain fatty acids (SCFA) were observed, especially in acetate and butyrate produced due to direct fermentation of pectin or by cross-feeding interaction between bacteria. This is the first study on the digestibility and fermentation of pectin carried out in a complex dynamic gastrointestinal simulator, being of special relevance the results obtained for F. prausnitzii.

    更新日期:2018-11-28
  • Nanoformulations of quercetin and cellulose nanofibers as healthcare supplements with sustained antioxidant activity
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-27
    Xiaohe Li, Yongzhuang Liu, Yanyan Yu, Wenshuai Chen, Yixing Liu, Haipeng Yu

    Given its health benefits to the human body, quercetin (QT) offers promising applications in the healthcare food and pharmaceutical industries. However, the instability, low water solubility and low bioavailability of QT remain to be solved. In this paper, cellulose nanofiber (CNF) was used as an effective nanoscale carrier to alleviate these problems. By adjusting the solvent composition ratio and processing method, QT was optimally immobilized on CNF surfaces and was eventually encapsulated in the CNF matrices, forming a CNF/QT nanoformulation. A high loading capacity of 78.91% and encapsulation efficiency of 88.77% were achieved simultaneously. The nanoformulation exhibited better dietary performance and antioxidant activity than raw QT. Moreover, sustained release of QT was demonstrated in vitro. These results reveal that CNF is an ideal natural nanoscale dietary carrier and offers high encapsulation efficiency for healthcare supplementation. This work also provides a promising nanoformulation candidate for managing sustained antioxidant requirements.

    更新日期:2018-11-28
  • Electrospinning in water and in situ crosslinking of hyaluronic acid / cyclodextrin nanofibers: Towards wound dressing with controlled drug release
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-27
    Morgane Seon-Lutz, Anne-Claude Couffin, Séverine Vignoud, Guy Schlatter, Anne Hébraud

    Hyaluronic acid (HA) is widely investigated due to its high potential for wound dressing applications. The fabrication of biomimetic HA-based scaffolds by electrospinning is thus extensively studied. However, HA is often dissolved in toxic organic solvents to allow the efficient production of electrospun nanofibers. Indeed, although HA is soluble in water, its ionic nature leading to long-range electrostatic interactions and the presence of counter ions induce a dramatic increase of the viscosity of aqueous HA solutions without insuring enough chain entanglements necessary for a stable and efficient electrospinning. In this study, biocompatible insoluble HA-based nanofibers were fabricated by electrospinning in pure water. To this end, poly(vinyl alcohol) (PVA) was added as a carrier polymer and it was found that the addition of hydroxypropyl-β-cyclodextrin (HPβCD) stabilized the process of electrospinning and led to the efficient formation of uniform nanofibrous scaffolds. An in situ crosslinking process of the scaffolds is also proposed, insuring a whole fabrication process without any toxicity. Furthermore, the beneficial presence of HPβCD in the HA-based scaffolds paves the way for wound dressing applications with controlled drug encapsulation-release properties. As a proof of concept, naproxen (NAP), a non-steroidal anti-inflammatory drug was chosen as a model drug. NAP was impregnated into the scaffolds either in aqueous solution or under supercritical CO2. The resulting functional scaffolds showed a regular drug release profile along several days without losing the fibrous structure. This study proposes a simple approach to form stable HA-based nanofibrous scaffolds embedding HPβCD using water as the only solvent, enabling the development of safe functional wound dressings.

    更新日期:2018-11-28
  • Inhibition of dextran sodium sulfate-induced colitis in mice by baker’s yeast polysaccharides
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-27
    Ying Sun, Xiaodan Shi, Xing Zheng, Shaoping Nie, Xiaojuan Xu

    Most of the reported yeast polysaccharides are a mixture of chitin, β-glucan and mannoprotein, leading to different data on its biological activity. Herein, we report the structures and the anti-inflammation of the purified baker’s yeast polysaccharides (BBG1-BBG4). Experimental data indicated that BBG1 was a highly branched β-(1,6)-glucan linked to mannoprotein; BBG2 was a linear β-(1,3)-glucan; BBG3 and BBG4 were mixtures of a β-(1,6)-branched β-(1,3)-glucan and a linear β-(1,3)-glucan. Of these, BBG1 exhibited stronger inhibition of pro-inflammatory mediators of NO/iNOS, IL-6, IL-1β, etc. at protein and/or mRNA levels in LPS-stimulated RAW264.7 cells through inhibiting MAPK signalling pathways. Orally administered BBG1 and BBG2 significantly decreased the pro-inflammatory mediators of IL-6, iNOS and IL-1β at protein and/or mRNA levels, as well as colonic mucosal damage and macrophages infiltration in DSS-induced colitis mice. All these findings suggest that yeast polysaccharides have potentials as anti-inflammatory drugs or adjuvants in the intestinal inflammation therapy.

    更新日期:2018-11-28
  • The study of inhibitory effects and mechanism of carboxylate chitooligomer on melanin, prepared by laccase/TEMPO system
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-26
    Xiaoqin Zhen, Dongzhao Hao, Jicheng Pei, Fangdong Zhang, Haitang Liu, Jing Wang, Nengyuan Bian, Xinli Zhang, Ying Li, Xin Bu

    A carboxylate chitooligomer (C-COS) containing carboxyl groups attached to chitooligomer (COS) molecules has been prepared by laccase/2,2,6,6-tetramethylpiperidine-1-oxyl (TEMPO) system, which is a green-chemistry method. Several experiments were designed to evaluate inhibition effects on melanin and mechanisms of C-COS. The results indicated that C-COS exhibited more distinct anti-melanogenic effects compared to COS. C-COS inhibits melanin production with tyrosine (Tyr) and DOPA as the substrate of melanin formation, and the inhibition rates are, respectively, 89.07% and 84.45%, which reach 1.4 to 2 times those of COS. UV-visible spectroscopy was used to elucidate the interaction mechanism between C-COS and tyrosinase (TYR). It is C-COS chelating with metal Cu ions in tyrosinase (TYR) that decreases the enzyme activity. Half-maximal inhibitory concentrations (IC50) of C-COS were calculated as 13.49 and 4.07 mg/mL for monophenolase (cresolase) and diphenolase (catecholase), respectively.

    更新日期:2018-11-27
  • Bio-based thin films of cellulose nanofibrils and magnetite for potential application in green electronics
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-26
    Ana Carolina Cunha Arantes, Luiz Eduardo Silva, Delilah F. Wood, Crislaine das Graças Almeida, Gustavo Henrique Denzin Tonoli, Juliano Elvis de Oliveira, Joaquim Paulo da Silva, Tina G. Williams, William J. Orts, Maria Lucia Bianchi

    The objective of this work was to prepare bio-based thin films and evaluate the additions of magnetite and glycerol on the physico-chemical (flexibility, wettability and barrier properties) and dielectric properties of cellulose/chitosan-based films. The films were prepared by solution casting and presented a suitable dispersion of the constituents observed by SEM and FTIR. The films were thermally stable up to 150 °C and had a higher flexibility, wettability and lower barrier properties upon addition of glycerol. The calculated dielectric constant (εr) for the composite films was based on measurements of capacitance, at 100 and 1000 Hz, with the additions of magnetite and glycerol more than doubling the εr increasing the charge storage capacity. The bio-based thin films have potential to be used as insulators in capacitors on the production of green electronics thus, reducing toxic and nonrenewable e-waste generation.

    更新日期:2018-11-27
  • A Comprehensive Review of Techniques for Natural Fibers as Reinforcement in Composites: Preparation, Processing and Characterization
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-26
    Sanjay MR, Suchart Siengchin, Jyotishkumar Parameswaranpillai, Mohammad Jawaid, Catalin Iulian Pruncu, Anish Khan

    Designing environmentally friendly materials from natural resources represents a great challenge in the last decade. However, the lack of fundamental knowledge in the processing of the raw materials to fabricate the composites structure is still a major challenge for potential applications. Natural fibers extracted from plants are receiving more attention from researchers, scientists and academics due to their use in polymer composites and also their environmentally friendly nature and sustainability. The natural fiber features depend on the preparation and processing of the fibers. Natural plant fibers are extracted either by mechanical retting, dew retting and/or water retting processes. The natural fibers characteristics could be improved by suitable chemicals and surface treatments. This survey proposes a detailed review of the different types of retting processes, chemical and surface treatments and characterization techniques for natural fibers. We summarize major findings from the literature and the treatment effects on the properties of the natural fibers are being highlighted.

    更新日期:2018-11-27
  • DFT study of the influence of acetyl groups of cellulose acetate on its intrinsic birefringence and wavelength dependence
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-26
    Daichi Hayakawa, Hiroaki Gouda, Shuichi Hirono, Kazuyoshi Ueda

    The effect of the acetyl groups of cellulose acetate (CA) on its intrinsic birefringence and its wavelength dependence was investigated using density functional theory (DFT). Seven types of CA repeating-unit models that differ in their degree of substitution (DS) and substitution sites were used in the calculations. The results suggested that the intrinsic birefringence (Δn°) and its wavelength dependence significantly depended on the conformations of the acetyl group at C6. Additionally, the intrinsic birefringence of CA films was estimated as the ensemble average of the calculated Δn° values of the conformers. The increase in the DS of CA led to a more negative intrinsic birefringence and a larger wavelength dependence. The computational results were in good qualitative agreement with the experimental results and suggested that conformational variety and/or its control would be important factors for the design of optical films containing CA.

    更新日期:2018-11-27
  • Banana Starch Nanocomposite with Cellulose Nanofibers isolated from Banana Peel by Enzymatic Treatment: In vitro Cytotoxicity Assessment
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-24
    H. Tibolla, F.M. Pelissari, J.T. Martins, E.M. Lanzoni, A.A. Vicente, F.C. Menegalli, R.L. Cunha

    The potential use of cellulose nanofibers (CNFs) as a reinforcing agent in banana starch-based nanocomposite films was investigated. CNFs were isolated from banana peel (Musa paradisiaca) by enzymatic hydrolysis. Banana starch-based nanocomposite films were prepared with CNFs using the casting method. CNFs effect on cell viability and on nanocomposite films properties’ was investigated. The cytotoxicity of CNFs was assessed on Caco-2 cell line. CNFs were not cytotoxic at 50-2000 μg/mL. However, CNFs above 2000 μg/mL significantly decreased cell viability. Topography analysis showed that the incorporation of CNFs modified the film structure. The nanocomposites exhibited a complex structure due to strong interactions between CNFs and starch matrix, promoting a remarkable improvement on mechanical and water barrier properties, opacity and UV light barrier compared to the control film. CNFs can offer a great potential as reinforcing material for starch-based nanocomposite films, producing a value-added food packaging from a waste material.

    更新日期:2018-11-26
  • Effects of Impulse-cyclone Drying and Silane Modification on the Properties of Wood Fiber/HDPE Composite Material
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-24
    Xun Gao, Lin Lin, Jiuyin Pang, Feng Chen, Qingde Li

    Poplar fibers were pretreated under impulse-cyclone drying (ICD) and further modified by different types of silane with special chemical structures. The effects of ICD-assisted silane modification on the properties of wood plastic composites (WPCs) were investigated. The main findings indicated that the number of hydroxyl groups and the polarity of the fibers decreased after the ICD/silane co-modification, whereas the hydrophobicity and crystallinity of fibers, the compatibility and adhesion strength between fibers and plastics, and the mechanical properties, thermostability, and dynamic mechanical properties of WPCs were significantly improved. In this study, when the wood fibers were only modified by silane and the silane content was 5%, the WPCs had better properties, and the WPCs modified with vinyl tri-methoxysilane (A-171) had the best properties. Furthermore, the addition of a small amount of silane to the wood fibers modified by ICD provided even better physical and mechanical properties compared to those of the WPCs that were only modified by silane; when 3% silane was added, there were increases of 10.67%, 10.22% and 9.4%, in the tensile, flexural and impact strengths, respectively, and an increase of 6.84% in the contact angle of the composites. The water absorption rate of the composite significantly decreased as well.

    更新日期:2018-11-26
  • Current advances and future perspectives of 3D printing natural-derived biopolymers
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-24
    Jun Liu, Lushan Sun, Wenyang Xu, Qianqian Wang, Sujie Yu, Jianzhong Sun

    3D printing enables the complex or customized structures production in high speed and resolution. However, the lack of bio-based materials with user-defined biochemical and mechanical property is a significant barrier that limits the widespread adoption of 3D printing for products fabrication. Development of eco-friendly natural-derived biopolymers for 3D printing technologies and their promising application in different areas are of huge academic, and environmental interests. This paper reviews the state-of-the-art in terms of 3D printing technology using natural-derived feedstocks, including lignocellulose, starch, algae, and chitosan-based biopolymers. Special consideration is given to the development of lignocellulosic materials, i.e. cellulose, hemicellulose, lignin, and their derivatives as 3D printing feedstocks. A strategical development roadmap with identified material property requirements, key challenges, as well as possible solutions was proposed. It serves as guideline aiming to explore natural-derived biopolymers as novel feedstocks for different 3D printing technologies that will be potentially applied in various areas.

    更新日期:2018-11-26
  • Effect of Nanocellulose Fiber Hornification on Water Fraction Characteristics and Hydroxyl Accessibility during Dehydration
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-24
    Qijun Ding, Jinsong Zeng, Bin Wang, Darong Tang, Kefu Chen, Wenhua Gao

    Hornification are usually occurred in cellulosic fibers and even in nanocellulose fibrils during dehydration process but their mesoscopic structural changes is not fully understood. Here we investigated the structural features of cellulose nanocrystals (CNCs) and cellulose nanofibrils (CNF) with different solid content. In order to avoid the effect of drying, liquid AFM mode was carried out in this work. The different water contents of nanocellulose were quantified by Differential Scanning Calorimetry (DSC). We showed evidence of extreme growth in radial direction in the redispersed nanocelluloses, analyzed by statistics of contours from microscopy images. The amount of free water, freezing bound water, and non-freezing bound water decreased gradually during water evaporation and were completely removed in sequence. In addition, the hydroxyl accessibility of both redispersed CNCs and CNF were reduced by 83.33% and 81.96% via evaluating the uptake of fluorescent dyes.

    更新日期:2018-11-26
  • Differential activity of lytic polysaccharide monooxygenases on celluloses of different crystallinity. Effectiveness in the sustainable production of cellulose nanofibrils
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-24
    Susana V. Valenzuela, Cristina Valls, Viviane Schink, Daniel Sánchez, M. Blanca Roncero, Pilar Diaz, Josefina Martínez, F.I. Javier Pastor

    A series of cellulosic substrates has been produced, treated with lytic polysaccharide monooxygenase (LPMO) from Streptomyces ambofaciens (SamLPMO10C), and analyzed by high performance anion exchange chromatography (HPAEC) with pulsed amperometric detection (PAD). The activity of the bacterial LPMO showed high variability depending on the origin and degree of crystallinity of the substrate. Additionally, we tested the effectiveness of SamLPMO10C in the nanofibrillation of flax, a high crystalline agricultural fiber, as a single pretreatment or in combination with cellulases. All pretreatments were followed by a mechanical defibrillation by high-pressure homogenization (HPH) to obtain cellulose nanofibrils (NFC). The combined LPMO-cellulase treatment showed higher fibrillation yield, optical transmittance and carboxylate content than control reactions. Therefore, it could be explored as a promising green alternative to reduce the energy consumption in the production of NFC. To our knowledge, this is the first study reporting the effect of a bacterial LPMO in nanocellulose production.

    更新日期:2018-11-24
  • Solid-state NMR method for the quantification of cellulose and polyester in textile blends
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    Simone Haslinger, Sami Hietala, Michael Hummel, Sirkka Liisa Maunu, Herbert Sixta

    The valorization of cellulose rich textile waste is promoted by the development of a novel solid-state NMR method for the quantification of cellulose and polyester in textile blends. We applied 13C CP-MAS NMR as a tool for the quantification and structural characterization of cellulose in cotton polyester blends. Gaussian functions were used to integrate the spectra obtained from a set of calibration standards in order to calculate a sigmoidal calibration curve. Acid hydrolysis was chosen as a reference method. The results demonstrated that solid-state NMR enables a reliable determination of cellulose and polyester in both preconsumer and postconsumer waste textiles and suggests a possible extension of the concept to blends of man-made cellulose fibers (MMCFs) and polyester.

    更新日期:2018-11-24
  • Characterization, bioactivity and pharmacokinetic study of a novel carbohydrate-peptide polymer: glycol-split heparin-endostatin2 (GSHP-ES2)
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    Feng Sun, Zhendong Wang, Zhifang Yang, Yan Li, Huifei Cui, Chunhui Liu, Dezong Gao, Fengshan Wang, Haining Tan

    Endostatin (ES) has attracted considerable attention for the treatment of anti-angiogenesis-related disorders. An 11-amino-acid peptide (ES2, IVRRADRAAVP) from the amino terminal of ES is of interest because it is the main active fragment of ES. However, both ES and ES2 have a poor stability and a short half-life, and other disadvantages need to be further resolved. Thus, we conjugated ES2 to glycol-split heparin derivatives (GSHPs) to yield the polymer-peptide conjugate, GSHP-ES2. This study showed that GSHP-ES2 exhibited increased stability, a wider pH activity range, better inhibition of endothelial cell proliferation, migration and tube formation in vitro, better anti-angiogenic activity and a longer half-life in vivo compared with ES2. These results also indicate that GSHP-ES2 has good potential for the treatment of angiogenesis-related diseases, either alone or in combination with other chemicals.

    更新日期:2018-11-24
  • Curdlan oligosaccharides having higher immunostimulatory activity than curdlan in mice treated with cyclophosphamide
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    Jiqing Tang, Hongmin Zhen, Nannan Wang, Qiaojuan Yan, Hao Jing, Zhengqiang Jiang

    This study evaluated the immunostimulatory activity of curdlan oligosaccharides (GOS) in cyclophosphamide (CTX)-induced immunosuppressed mice and in RAW264.7 cells. GOS was able to stimulate the release of nitric oxide (NO), cytokines (IL-1β, IL-6 and TNF-α) and improve the phagocytic rate of peritoneal macrophages and RAW264.7 cells. It further enhanced immunoglobulins (Ig) release (IgG by 50.6%~74.7%, IgA by 31.3%~34.9%, IgM by 28.3%~66.7%), splenic lymphocyte proliferation (by 74.8%~91.3%), nature killer cells cytotoxicity (by 32.0%~49.6%), immunophenotypes of splenic lymphocytes (from 1.7 to 2.4, 2.2 and 2.7) in immunosuppressed mice. Compared with curdlan, higher immunostimulatory activity of GOS was found in CTX-treated mice. Moreover, GOS could activate nuclear factor kappa-light-chain-enhancer of activated B cells (NF-κB) and mitogen-activated protein kinase (MAPK) signaling pathways through toll-like receptor 2 (TLR2) and complement receptor 3 (CR3). These results indicated that GOS may be a favorable candidate of functional food in regulating immune responses.

    更新日期:2018-11-24
  • Quaternized Trimethyl Functionalized Chitosan Based Antifungal Membranes for Drinking Water Treatment
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    Ayesha Tabriz, Muhammad Azeem Ur Rehman Alvi, Muhammad Bilal Khan Niazi, Mehwish Batool, Muhammad Faraz Bhatti, Asim Laeeq Khan, Asad U. Khan, Tahir Jamil, Nasir M. Ahmad

    Chitosan was functionalized to synthesize Quaternized N-trimethyl chitosan (TMC) and incorporated in polyethersulfone (PES) polymer to fabricate membranes for enhanced antifungal activity and water treatment. The TMC was synthesized from chitosan via reductive alkylation and methylation. The effect of concentration of chitosan and TMC on the properties of functionalized PES membranes was investigated. The membrane with the lowest concentration of TMC 5% (w/w) resulted in the largest average pore size than the PES membrane without chitosan or TMC. The surface wettability was enhanced as contact angle was reduced from 90º to 57º by increasing concentration of TMC to 15% (w/w). The resultant membranes exhibited improved water hydrophilicity, permeability and inhibition against fungal species. The functionalized membranes had shown noticeable antifungal activity against Aspergillus niger in the case of 15% TMC with 72% antifungal activity and 15% chitosan with 63 % antifungal activity against Fusarium solani.

    更新日期:2018-11-24
  • Hydrogen-bonding Network in Anhydrous Chitosan from Neutron Crystallography and Periodic Density Functional Theory Calculations
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    Yu Ogawa, Philip-Kunio Naito, Yoshiharu Nishiyama

    The hydrogen-bonding network in anhydrous chitosan crystal was studied using a combination of neutron crystallography and quantum chemical calculation. The locations of the hydroxyl hydrogen were directly resolved using Fourier omit maps applied to neutron diffraction data, whereas the amino hydrogen atoms were determined based on geometrical optimization using periodic density functional theory (DFT) calculation. Energy optimization of the hydrogen positions based on DFT calculation allowed the measurement of the hydrogen-bond energies. In the chitosan crystal, the hydroxyl groups mostly play a role as hydrogen-bond donors while the amino moiety behaves as a strong acceptor but a poor donor.

    更新日期:2018-11-24
  • Alkyne functionalized cellulose fibers: a versatile “clickable” platform for antibacterial materials
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    Lijian Sun, Guifa Xiao, Xueren Qian, Xianhui An

    We report a facile and effective method to fabricate clickable alkyne-functionalized cellulose fibers (ACFs) through in situ chemical oxidation copolymerization of 3-ethynylaniline and aniline under acidic aqueous solution. The effects of process variables on copolymer deposition onto CFs were investigated and suitable preparation conditions were identified. It was found that aniline significantly facilitated the polymerization of 3-ethynylaniline and shortened the preparation time of ACFs from 48 to 6 h. Antibacterial-modified cellulose fibers were prepared by binding β-cyclodextrin (β-CD) to cellulose fibers via click chemistry, followed by the inclusion of ciprofloxacin hydrochloride (CipHCl). The loading and releasing behaviors of CipHCl into/from click product (ACFs@Azide-β-CD) were also revealed. The load amount of CipHCl into ACFs@Azide-β-CD increased remarkably, and the release of CipHCl from ACFs@Azide-β-CD was prolonged. The ACFs@Azide-β-CD loaded with CipHCl exhibited higher and longer-term antibacterial activity against Escherichia coli (E. coli) and Staphylococcus aureus (S. aureu) compared with CFs and ACFs.

    更新日期:2018-11-24
  • Polysaccharide produced by Bacillus subtilis using burdock oligofructose as carbon source
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    Lei Xu, Yan Lu, Yunzhe Cong, Pengying Zhang, Jun Han, Ge Song, Guodong Wang, Kaoshan Chen

    In this study, a polysaccharide, BP, was produced by Bacillus subtilis using burdock oligofructose as a carbon source. The polysaccharide BP was isolated from burdock fermented through B. subtilis by hot water extraction, ethanol precipitation, anion exchange and gel filtration chromatography. The molecular weight of BP was determined to be 1.533 × 107 g/mol, and is composed of mannose, rhamnose, glucose, galactose, and arabinose in the ratio of 1:0.12:17.16:0.69:1.10. Furthermore, BP is made up of a backbone structure of (1→6)-linked α-D-glucopyranosyl residues substituted at the O-3 position with α-D-glucopyranosyl branches. In vitro, BP inhibited A549 cell proliferation and increased reactive oxygen species production, thus, promoting the apoptosis of cells. Moreover, BP up-regulated the expression of caspase-3 and the corresponding protein, indicating that it activates the caspase-3 pathway. These findings suggest that the potential of BP as a supplement or drug to treat cancer.

    更新日期:2018-11-24
  • Crosslinking of chitosan films processed by compression molding
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-22
    P. Guerrero, A. Muxika, I. Zarandona, K. de la Caba

    An alternative approach towards more sustainable chitosan films, through their manufacture by thermo-compression molding, was explore in this work. This strategy permitted the reduction of production times and avoided the use of organic solvents since biopolymer and acid were mixed in their solid form. Furthermore, the acid used as a crosslinker was citric acid, a natural policarboxylic acid, which promoted the reaction with chitosan, as shown by Fourier transform infrared (FTIR) spectroscopy, differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). This crosslinking reaction led to the formation of homogeneous structures, as observed by scanning electron microscopy (SEM), indicating a good compatibility among all the components of the mixture and enhancing the mechanical properties of the resulting films. In particular, an increase of 80% for tensile strength and an increase of 3000% for elongation at break were observed for the crosslinked films. In addition to the homogeneous surface of citric acid-incorporated films, all the films showed hydrophobic character and the addition of citric acid led to a more amorphous structure. In sum, citric acid-incorporated chitosan films manufactured by compression molding were found to show potential for food and pharmaceutical applications.

    更新日期:2018-11-24
  • β-chitin samples with similar microfibril arrangement change mechanical properties varying the degree of acetylation
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-23
    Devis Montroni, Simona Fermani, Kavin Morellato, Giangiacomo Torri, Annamaria Naggi, Luca Cristofolini, Giuseppe Falini

    Chitin is widespread in nature and is increasingly used in synthetic process for the production of new biomaterials. Chitin degree of acetylation, crystalline structure and microfibril arrangement differentiate chemical, physical and mechanical properties. Nevertheless, no information are available on the relationship between the mechanical properties and the degree of acetylation (DA) in chitin samples in which the microfibril arrangement does not change. Here, samples of β-chitin with decreasing DA, up to chitosan, were prepared using the squid pen of Loligo vulgaris. These samples were characterized by CP-MAS NMR spectroscopy, scanning electron microscopy, thermal analyses, synchrotron X-ray fiber diffraction and tensile tests. The results showed a similar microfibril arrangement decreasing the DA, except for the chitosan sample. The mechanical properties showed an increase of the maximum strain and a reduction of the maximum stress and Young’s modulus, decreasing the DA. These changes, not linear with the DA, were related to structural changes at molecular structure level. The knowledge deriving from this study is of interest both for the understanding of the mechanical properties of chitinous biological samples, but also for the design and synthesis of new biomacromolecular materials.

    更新日期:2018-11-24
  • Solvent-free synthesis of acetylated cashew gum for oral delivery system of insulin
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-23
    Eliadna de Lemos Vasconcelos Silva, Antônia Carla de Jesus Oliveira, Yuri Basílio Gomes Patriota, António José Ribeiro, Francisco Veiga, Fernando Hallwass, Edson Cavalcanti Silva-Filho, Durcilene Alves da Silva, Monica Felts de La Roca Soares, Almir Gonçalves Wanderley, José Lamartine Soares-Sobrinho

    Cashew gum (CG) is a biopolymer that presents a favorable chemical environment for structural modifications, which leads to more stable and resistant colloidal systems. The gum was subjected to an acetylation reaction using a fast, simple, solvent-free and low cost methodology. The derivative was characterized by infrared and NMR spectroscopy, elemental analysis, coefficient of solubility and zeta potential. The modified biopolymer was used as a platform for drug delivery systems using insulin as a model drug. Nanoparticles were developed through the technique of polyelectrolytic complexation and were characterized by size, surface charge, entrapment efficiency and gastrointestinal release profile. The nanoparticles presented size of 460 nm with a 52.5% efficiency of entrapment of insulin and the electrostatic stabilization was suggested by the zeta potential of + 30.6 mV. Sustained release of insulin was observed for up to 24 hours. The results showed that acetylated cashew gum (ACG) presented potential as a vehicle for sustained oral insulin release.

    更新日期:2018-11-24
  • Bacterial cellulose production by Gluconacetobacter entanii using pecan nutshell as carbon source and its chemical functionalization
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-23
    R.F. Dórame-Miranda, N. Gámez-Meza, L.Á. Medina-Juárez, J.M. Ezquerra-Brauer, M. Ovando-Martínez, J. Lizardi-Mendoza

    Pecan nutshell is an abundant waste with a high content of carbohydrates. According to its chemical composition, pecan nutshell could be used as carbon source for Gluconacetobacter entanii, a bacterium that produces cellulose with high purity and nanometric characteristics. Bacterial cellulose (BC) was obtained from a static culture medium using pecan nutshell as carbon source and saccharose as control. Results showed that the pecan nutshell could be used as carbon source for production of BC. The cellulose yield ranged around 2.816 ± 0.040 g/L for 28 days. The morphological, structural and chemical properties of the cellulose produced were similar to those reported for others BC. The spectroscopic characterization indicated the chemical functionalization of BC and the reduction of its crystallinity. The production of BC with G. entanii using pecan nutshell as carbon source, is the first report. The BC could have potential use in chemical functionalization and in the preparation of biocomposites.

    更新日期:2018-11-24
  • Vine shoots as new source for the manufacture of prebiotic oligosaccharides
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-23
    Izaskun Dávila, Beatriz Gullón, José Luis Alonso, Jalel Labidi, Patricia Gullón

    Vine shoots were subjected to a hydrothermal treatment to cause the selective solubilisation of the hemicelluloses. The hemicelluloses solubilisation products were refined by a sequential processing with nanofiltration and ion exchange obtaining a refined product with a purity of 99%. A depth chemical and structural characterization of the purified oligosaccharide mixture from vine shoots was performed for the first time by HPLC, FTIR, HPAEC-PAD, MALDI-TOF and UPLC-DAD-ESI-MS. The characterization showed the presence of oligosaccharide mixtures with a wide polymerization degree (DP = 2-17) and a rich substitution pattern. Moreover, the thermal behaviour of the mixture was evaluated by TGA in order to obtain information about the thermal and storage conditions during its incorporation into processed functional foods. The thermal and acid stability of the obtained oligosaccharides was also evaluated corroborating their resistance to the digestive conditions. The assessment of the prebiotic activity of the digested mixture was carried out by in vitro fermentability with faecal inocula from human volunteers by the monitoring of short chain fatty acids production and the population dynamic of bifidobacteria by FISH.

    更新日期:2018-11-24
  • Effect of lignin-based amphiphilic polymers on the cellulase adsorption and enzymatic hydrolysis kinetics of cellulose
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-23
    Xuliang Lin, Linjun Wu, Siqi Huang, Yanlin Qin, Xueqing Qiu, Hongming Lou

    The origin, amount, hydrophilicity, charge, molecular weight and its distribution of lignin have significant influences on the enzymatic hydrolysis of lignocellulose. The enzymatic hydrolysis of lignocellulose was essentially enhanced by lignin-based polyoxyethylene ether (EHL-PEG), whereafter followed by PEG4600 and lignosulfonate (LS). The effect of LS, EHL-PEG and PEG4600 on the adsorption and enzymatic hydrolysis kinetics of cellulase on the gold surface and cellulose film was investigated by Quartz Crystal Microbalance with dissipation monitoring (QCM-D). Results showed that the interaction of LS or EHL-PEG with cellulase was electrostatic attractive and hydrophobic effect, respectively, and formed hydrophilic cellulase aggregates. LS-Cellulase peeled off the cellulose film layer by layer, while the hydrophobic phenylpropane structure of EHL-PEG-Cellulase acted as a cellulose binding domain to hydrolysis cellulose through “Hollow” effect and made cellulose become more loose and swollen. At last, a strategy to enhance the enzymatic hydrolysis of lignocellulose by lignin-based amphiphilic polymers was proposed as well.

    更新日期:2018-11-24
  • β-cyclodextrin based dual-responsive multifunctional nanotheranostics for cancer cell targeting and dual drug delivery
    Carbohydr. Polym. (IF 5.158) Pub Date : 2018-11-20
    Manita Das, Solanki Archana, Joshi Apeksha, Devkar Ranjitsinh, Seshadri Sriram, Thakore Sonal

    Multifunctional nanoconjugates possessing an assortment of key functionalities such as magnetism, florescence, cell-targeting, pH and thermo-responsive features were developed for dual drug delivery. The novelty lies in careful conjugation of each of the functionality with magnetic Fe3O4 nanoparticles by virtue of urethane linkages instead of silica in a simple one pot synthesis. Further β-cyclodextrin (CD) was utilized to carry hydrophobic as well as hydrophilic drug. Superlative release of DOX could be obtained under acidic pH conditions and elevated temperature, which coincides with the tumor microenvironment. Mathematical modelling studies revealed that the drug release kinetics followed diffusion mechanism for both hydrophobic drug and hydrophilic drug. A number of fluorophores onto a single nanoparticle produced a strong fluorescence signal to optically track the nanoconjugates. Enhanced internalization due to folate specificity could be observed by fluorescence imaging. Further their accumulation driven by magnet near tumor site led to magnetic hyperthermia.In vitro studies confirmed the nontoxicity and hemocompatibility of the nanoconjugates. Remarkable cell death was observed with drug-loaded nanoconjugates at very low concentrations in cancer cells. The internalization and cellular uptake of poor bioavailable anticancer agent curcumin were found to be remarkably enhanced on dosing the drug loaded nanoconjugates as compared to free curcumin. Site specific drug delivery due to folate conjugation and subsequent significant suppression in tumor growth was demonstrated by in vivo studies.

    更新日期:2018-11-20
Some contents have been Reproduced with permission of the American Chemical Society.
Some contents have been Reproduced by permission of The Royal Society of Chemistry.
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