COLLOIDS AND SURFACES B-BIOINTERFACES
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2015
·
IF 4.152
Yunfei Mo,Rui Guo,Jianghui Liu,Yong Lan,Yi Zhang,Wei Xue,Yuanming Zhang
Although extensively used in the fields of drug-carrier and tissue engineering, the biocompatibility and mechanical properties of polylactide–polyglycolide (PLGA) nanofiber membranes still limit their applications. The objective of this study was to improve their utility by introducing cellulose nanocrystals (CNCs) into PLGA nanofiber membranes. PLGA and PLGA/CNC composite nanofiber membranes were prepared via electrospinning, and the morphology and thermodynamic and mechanical properties of these nanofiber membranes were characterized by scanning electron microscopy (SEM), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and dynamic mechanical analysis (DMA). The cytocompatibility and cellular responses of the nanofiber membranes were also studied by WST-1 assay, SEM, and confocal laser scanning microscopy (CLSM). Incorporation of CNCs (1, 3, 5, and 7 wt.%) increased the average fiber diameter of the prepared nanofiber membranes from 100 nm (neat PLGA) to ∼400 nm (PLGA/7 wt.% CNC) and improved the thermal stability of the nanofiber membranes. Among the PLGA/CNC composite nanofiber membranes, those loaded with 7 wt.% CNC nanofiber membranes had the best mechanical properties, which were similar to those of human skin. Cell culture results showed that the PLGA/CNC composite nanofiber membranes had better cytocompatibility and facilitated fibroblast adhesion, spreading, and proliferation compared with neat PLGA nanofiber membranes. These preliminary results suggest that PLGA/CNC composite nanofiber membranes are promising new materials for the field of skin tissue engineering.
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RSC Advances
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2016
·Vol. 6
·期 55
·49528-49536
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IF 3.289
Jie Zou,Dong Cao,Weitong Tao,Shaoyin Zhang,Li Cui,Fanli Zeng,Weijie Cai
The dehydration of sorbitol to isosorbide over an environmentally benign cellulose-derived solid acid catalyst (CCS) has been investigated in order to develop a sustainable process for isosorbide production. The as-prepared CCS sample contained large amounts of –COOH, phenolic hydroxyl and –SO3H groups and presented satisfactory catalytic activity, isosorbide selectivity and recyclability under water-free conditions. Various methods such as BET, XPS, TG, SEM, FT-IR and pyridine adsorption were conducted to characterize the CCS catalyst in order to elucidate the possible catalyst structure–performance relationship. The results of FT-IR and pyridine adsorption revealed that most of the acid sites contained in CCS catalyst were assigned as strong Brönsted sites, which were crucial for catalytic sorbitol dehydration into isosorbide. When further compared to the conventional solid acid catalyst (niobic acid), the investigated CCS catalyst in this study was considered as one of the promising alternatives to the highly efficient catalysts for isosorbide production from sorbitol.
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JOURNAL OF APPLIED POLYMER SCIENCE
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2016
·Vol. 134
·期 2
·
IF 1.866
Zhi Chen,Ting Wang,Xiufeng Yan
Current cyclodextrin (CD) hydrogels have disadvantages, including a limited CD content, long reaction time, and complicated chemical reactions. To overcome these, a one-pot reaction was adopted, and a concept of a β-CD hydrogel cage was proposed. Hydroxyethyl cellulose (HEC) was used as the raw material with the adjustment of the stoichiometric relationship among the crosslinking agent of epichlorohydrin, alkali environment, and β-CD amount, and an elastic β-CD hydrogel cage system was established. After the β-CD was caged, the contents of active β-CD in hydrogel products reached 74.45 and 69.14 wt % by weight measurement and photometric titration, respectively. Furthermore, compared to the pure HEC hydrogel, the hydrogel mechanical strength improved obviously after the β-CD was caged, and we obtained a faster water swelling rate at the same time. Finally, a hydrophobic molecule of phenolphthalein (PP) was used to evaluated the activity of caged β-CD in the hydrogel. In addition, the absorption and release of PP by an elastic β-CD hydrogel cage at certain time intervals were also studied. The results demonstrate that the β-CD hydrogel cage was used as a functional molecule carrier to quickly absorb and sustain the release of PP. © 2016 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2017 , 134 , 44388.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2017
·
IF 3.671
Wei Wang,Qian Bai,Tao Liang,Huiyu Bai,Xiaoya Liu
The modification of regenerated cellulose (RC) membranes was carried out by using silane coupling agents presenting primary and secondary amino-groups. The grafting of the amino groups onto the modified cellulose molecule was confirmed by X-ray photoelectron spectroscopies and 13 C nuclear magnetic resonance spectroscopic analyses. The crystallinity of the cellulose membranes (CM) decreased after chemical modification as indicated by the X-ray diffraction results. Moreover, a denser structure was observed at the surface and cross section of the modified membranes by SEM images. The contact angle measurements showed that the silane coupling treatment enhanced the hydrophobicity of the obtained materials. Then the catalytic properties of two types of modified membranes were studied in a batch process by evaluating their catalytic performance in a Knoevenagel condensation . The results indicated that the cellulose membrane grafted with many secondary amines exhibited a better catalytic activity compared to the one grafted only by primary amines. In addition, the compact structure of the modified membranes permitted their application in a pervaporation catalytic membrane reactor. Therefore, functional CM that prepared in this paper represented a promising material in the field of industrial catalysis.
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Journal of Materials Chemistry A
·
2017
·Vol. 5
·期 31
·16289-16295
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IF 8.867
Jing-Jing Wang,Hao-Cheng Yang,Ming-Bang Wu,Xi Zhang,Zhi-Kang Xu
Nanofiltration membranes are of great interest in brackish water desalination and drinking water purification. Improving the permeation and separation performance remains a big challenge in advanced nanofiltration membranes. Herein, we report triple-layered composite nanofiltration membranes constructed by the interfacial polymerization of diamine and acyl chloride on a cellulose nanocrystal interlayer supported by a microporous substrate. The cellulose nano-crystal interlayer plays a crucial role in the polyamide skin layer formation and the following nanofiltration process. It can store aqueous diamine monomers and slow down the interfacial polymerization for a relatively low cross-linking degree of the skin layer. This hydrophilic interlayer also facilitates water permeation through a “dragging effect”. The constructed membranes exhibit an ultra-high permeation flux up to 204 L m−2 h−1 under 0.6 MPa with a Na2SO4 rejection above 97%, which is the highest reported result to our knowledge. The ultra-high water permeation flux enables nanofiltration at low operating pressure, making it an energy-saving process. Moreover, the low cross-linking degree of the skin layer results in a high monovalent/divalent ion separation ratio.
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Scientific Reports
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2017
·Vol. 7
·期 1
·1-10
·
IF 4.259
Wu Xia,Zhang Li,Zhang Xingzhong,Zhu Ya,Wu Yuehan,Li Yan,Li Bin,Liu Shilin,Zhao Jinping,Ma Zhaocheng
Ethyl cellulose (EC) nanodispersions have been prepared through a facile procedure, a process involved the dissolution of EC into ethanol, followed by dipping it in Xanthan Gum (XG) solution (0.1%, used as anti-solvent), and then removed the ethanol. The influences of preparation conditions on the structure and properties of the EC nanodispersions were investigated. The prepared EC nanodispersion had a negative surface potential, which contributed to its stabilization. The particle size of the nanodispersions could be controlled by changing the concentration of EC. Furthermore, the EC nanodispersions had a potential application for the stabilization of oil/water Pickering emulsion. The obtained Pickering emulsions showed high stability.
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CELLULOSE
·
2017
·Vol. 24
·期 12
·5403-5415
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IF 3.417
Deng Lin,Chang Chun,An Ran,Qi Xiaoge,Xu Guizhuan
Direct production of butyl levulinate (BL) by butanolysis of cellulose was carried out using single or combined metal sulfates catalysts. The synergetic enhancement of the ferric sulfate and aluminum sulfate can improve the conversion of cellulose to BL. Moreover, the butanolysis of cellulose was optimized by using response surface methodology. Under the optimum conditions of 194 °C, catalyst concentration 10.0 g/L and reaction time 3 h, the average cellulose conversion of 100% and BL yield of 40.3% were obtained. In addition, the analysis of liquid products and the characterization of catalyst were performed, and the reusability experiments showed that the metal sulfates can be easily recycled and be reused more than five times with high activity in the butanolysis process. This study provided an economical and feasible method for bio-based BL production from cellulose.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2017
·
IF 3.671
Ziqie Rao,Hongyu Ge,Liangling Liu,Chen Zhu,Lian Min,Meng Liu,Lihong Fan,Dan Li
Nanotechnology has been studied to improve drug delivery and cancer treatment. The aim of this study is to introduce amino groups into graphene oxide (GO) to form aminated fumed graphene (GO-ADH) and combine GO-ADH with carboxymethyl cellulose (CMC) to produce GO-CMC complex as a drug carrier matrix. The anti-cancer drug small molecule doxorubicin hydrochloride (DOX) was bond to GO-CMC by π-π bond interaction and hydrogen bonding to form GO-CMC/DOX drug loading system. Via the FT-IR, transmission electron microscopy (TEM) and Zeta potential analyzer analysis showed that GO-CMC complex was successfully synthesized. Studies have shown that when pH = 5.0, the cumulative release rate of drugs can reach 65.2%, which means it has pH-sensitive ability. The cells were treated with MTT method and human cervical cancer cells (Hela cells) and mouse fibroblasts (NIH-3T3 cells). The results showed that GO-CMC had no obvious cytotoxicity and good biocompatibility.
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Nanoscale
·
2015
·Vol. 7
·期 32
·13694-13701
·
IF 7.394
Yuanyuan Song,Yaoquan Jiang,Liyi Shi,Shaomei Cao,Xin Feng,Miao Miao,Jianhui Fang
Natural biomass based cellulose nanopaper is becoming a promising transparent substrate to supersede traditional petroleum based polymer films in realizing future flexible paper-electronics. Here, ultrathin, highly transparent, outstanding conductive hybrid nanopaper with excellent mechanical flexibility was synthesized by the assembly of nanofibrillated cellulose (NFC) and silver nanowires (AgNWs) using a pressured extrusion paper-making technique. The hybrid nanopaper with a thickness of 4.5 μm has a good combination of transparent conductive performance and mechanical stability using bamboo/hemp NFC and AgNWs cross-linked by hydroxypropylmethyl cellulose (HPMC). The heterogeneous fibrous structure of BNFC/HNFC/AgNWs endows a uniform distribution and an enhanced forward light scattering, resulting in high electrical conductivity and optical transmittance. The hybrid nanopaper with an optimal weight ratio of BNFC/HNFC to AgNWs shows outstanding synergistic properties with a transmittance of 86.41% at 550 nm and a sheet resistance of 1.90 ohm sq−1, equal to the electronic conductivity, which is about 500 S cm−1. The BNFC/HNFC/AgNW hybrid nanopaper maintains a stable electrical conductivity after the peeling test and bending at 135° for 1000 cycles, indicating remarkably strong adhesion and mechanical flexibility. Of importance here is that the high-performance and low-cost hybrid nanopaper shows promising potential for electronics application in solar cells, flexible displays and other high-technology products.
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BIORESOURCE TECHNOLOGY
·
2013
·
IF 4.75
Jinping Ni,Hailiang Wang,Yinying Chen,Zhen She,Haining Na,Jin Zhu
A two-step acid-catalyzed hydrolysis methodology is established to effectively hydrolyze cellulose to glucose with high yield and selectivity under mild conditions. In multi-steps hydrolysis, the difficulty of cellulose can be effectively reduced under mild conditions. In the first step, microcrystalline cellulose was depolymerized in phosphoric acid to cellulose oligomer at 50 °C. Then the oligomer was precipitated by ethanol and hydrolyzed with dilute sulfuric acid in the second step. 87.7% total reducing sugars and 57.8% glucose was released from the two-step hydrolysis process. In addition, with the assistance of microwave in the second step, the yield and selectivity of glucose can be improved to 73.3% and 80.1% by only 5 min hydrolysis. The two-step hydrolysis exhibits an effective process to produce glucose in cellulose hydrolysis. The enhancement of hydrolysis reactivity is considered to be controlled with the decrease of crystallinity and degree of depolymerization of cellulose.
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CELLULOSE
·
2013
·Vol. 20
·期 1
·179-190
·
IF 3.476
Shang Wulin,Huang Jin,Luo Huan,Chang Peter R.,Feng Jiwen,Xie Guangyong
Hydrophobic cellulose nanocrystals (CNs) have been prepared by grafting isocyanate-terminated castor oil, a kind of natural vegetable oil, onto their surface. The existence of castor oil component in the modified cellulose nanocrystals was verified by Fourier transform infrared spectroscopy, solid-state 13 C NMR spectra and X-ray photoelectron spectroscopy. At the same time, X-ray diffraction and transmission electron micrographs further proved that the crystalline structure and large aspect ratio of cellulose nanocrystals were essentially preserved after chemical grafting. Furthermore, the surface of modified cellulose nanocrystals appeared to be hydrophobic as indicated by contact angle measurements. The value of the polar component of surface energy decreased from 21.5 mJ/m 2 to almost zero via grafting castor oil. These novel hydrophobic castor oil-grafted cellulose nanocrystals appear as valuable alternatives to formulate bionanocomposites with non-polar polymers for optimized performances.
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CARBOHYDRATE POLYMERS
·
2013
·
IF 3.479
Lipeng Zhou,Zhen Liu,Meiting Shi,Shanshan Du,Yunlai Su,Xiaomei Yang,Jie Xu
Sulfonated hierarchical H-USY zeolite was prepared and characterized by X-ray diffraction, N 2 physisorption, Fourier transform infrared spectroscopy, inductively coupled plasma atomic emission spectroscopy, temperature-programmed desorption of ammonia, and acid–base titration. It was proved that sulfonic group was successfully anchored onto the hierarchical H-USY zeolite. The acidity of the hierarchical H-USY was remarkably improved. Sulfonated hierarchical H-USY zeolite was efficient for the hydrolysis of hemicellulose and cellulose. The yield of TRS for hydrolysis of hemicellulose reached 78.0% at 140 °C for 9 h. For hydrolysis of α-cellulose, 60.8% conversion with 22.4% yield of glucose was obtained. Even for microcrystalline cellulose, 43.7% conversion with 15.1% yield of glucose can be obtained. These results are much higher than those obtained over hierarchical H-USY zeolite, indicating that both the acidity and the pore structure determine the activity of zeolite as catalyst in the hydrolysis of biomass.
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