CARBOHYDRATE POLYMERS
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2021
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IF 9.381
Shuangyu Xiong,Wei Sun,Rong Chen,Zhiqiang Yuan,Xinjian Cheng
Fluorescent hydrogel with proper hydrophilicity and thermal stability , excellent sensitivity and high selectivity has important practical and scientific significance, especially in heavy metal ion detection. In this work, by adjusting the content of [2, 6-Bis-[4-formylthiophene]]-1,3,5,7-tetramethyl-8-phenyl-4, 4-difluoroborazaindoloene (B3), as a cross-linking agent, a series of chitosan- fluoroboron dipyrrole-chitosan-based fluorescent hydrogels (CBC) with large stokes shift were designed and prepared. The hydrogels can be used as fluorescent probes for identifying Cu 2+ in aqueous solution. The linear quenching range of Cu 2+ is 0–50 μM, and the detection limit and quenching constant are 4.75 μM and 3.52 × 10 4 M −1 , respectively. Under the interaction of Cu 2+ , the imine bond C N was converted to C- N bond, which causes the phenomenon of fluorescence quenching . In addition, relatively high crosslink density improves hydrophilicity and thermal stability of initial chitosan, and made the swelling ability better.
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Carbohydrate Polymer Technologies and Applications
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2021
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IF 0
Ali A. Altam,Liping Zhu,Wentao Huang,Hao Huang,Shuguang Yang
Spherical beads made of naturally derived polymers can be widely used as a promising matrix in many bio-related and safety required fields. Herein, the optimal parameters for fabrication of a core-shell bead composed of carboxymethylcellulose (CMC) and chitosan (CHI) are established based on systematic investigations on working distance, solution pH and polymer concentrations. Spherical beads will be obtained when the working distance is set as 15 cm. The beads prepared at pH 4.5 are the strongest and can resist to a force of up to 0.071 N. It will be shown that the critical concentration of polymer solutions plays important roles in determining the shape and size of beads. The observation of two new peaks at 1723 cm −1 and 1592 cm −1 in the FTIR of the prepared beads demonstrate the electrostatic interactions between CMC and CHI. With a post gentle heating (35°C), the stability of beads is significantly improved and the swelling degree in water increases to 220%.
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INTERNATIONAL JOURNAL OF HYDROGEN ENERGY
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2021
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IF 5.816
Yuqing Chi,Shuyi Zheng,Xiangwen Zhang,Guozhu Li
Selective hydrogenation of nitroarene to aniline is a key reaction for the manufacture of fine chemicals, pharmaceuticals, and dyes. In this study, N-doped carbon nanotubes (NCNTs) are prepared by the pyrolysis of chitosan-CNTs composite. The outside diameter of CNTs, concentration of chitosan, pyrolysis temperature and heating rate are tuned to improve the catalytic performance. The catalyst of CS/CNTs-800 doped with 0.33% pyrrolic N and 0.30% graphitic N exhibits good activity and high selectivity for the hydrogenation of nitroarenes. The kinetics data reveal that the hydrogenation reaction is zero-order for 4-nitrophenol and first-order dependence to H 2 pressure, and H 2 dissociation on the active sites is the rate-determining step. On CS/CNTs-800, the nitro groups of 12 different substrates can be selectively reduced with the protection of the other reducible groups. Nonpolar H radicals are found to be formed on CS/CNTs-800 for efficient hydrogenation. In addition, the catalyst showed good stability.
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JOURNAL OF ENVIRONMENTAL MANAGEMENT
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2021
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IF 6.789
Yongjun Sun,Deng Li,Xi Lu,Jinwei Sheng,Xing Zheng,Xuefeng Xiao
In this study, two multifunctional nano-chitosan flocculants (CPAM-NCS1 and CPAM-NCS2) were made through the graft modification of cationic monomer and carboxymethylchitosan (CMCTS) to remove combined contaminants. The effects of various factors (pH, flocculant dosage and hydraulic mixing conditions) on the flocculation performance under single and composite pollution conditions were systematically investigated, the optimal chemical oxygen demand (COD) and the chromaticity removal rates in the dye wastewater were 79.9% and 83.9% at wastewater pH 7, the fast stirring rate 300 rpm, the fast stirring time 8 min, and the dosage of CPAM-NCS1 80 mg/L, respectively. The optimal removal rates of Cu (II) obtained by CPAM-NCS1 and CPAM-NCS2 at were 80.3% and 75.2% at 60 mg/L and the wastewater pH 7, respectively. The optimal removal rates of Cu (II) and disperse orange were 85.3% and 89.4%, respectively, in a composite pollutant system in which Cu (II) and disperse orange coexisted when the pH of the composite system was 9 and the dosage of CPAM -NCS1 was 60 mg/L. This study proved that nanoflocculants made by modifying CMCTS with different structures can demonstrate ideal flocculation removal performance for dye and heavy metal wastewaters.
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Materials Today Communications
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2021
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IF 3.383
Jun-Lan Yang,Hou-Qun Yuan,Bao-Sheng Liu,Jia-Xin He,Qing Fan,Ke Deng,Deping Song,Guang-Ming Bao
Enrofloxacin is a broad spectrum antibacterial agent with an excellent killing effect against bacteria, commonly infecting the respiratory and intestinal tracts of livestock and poultry. However, its bitter taste and significant irritation to the gastrointestinal tract often lead to a failure of the commonly used current drug delivery system to achieve the desired therapeutic effect due to inefficient release of drugs. In the present study, pH-responsive enrofloxacin nanoparticles ( ENR-NPs ) for treating bacterial infections were fabricated through a facile one-pot approach to achieve the amphiphilic functionalization of chitosan (CS) through acid-labile Schiff-base with cinnamaldehyde and drug encapsulation. The structure and morphology of ENR-NPs were characterized by FTIR, X-Ray Diffraction (XRD), transmission electron microscopy (TEM), and dynamic light scattering (DLS). The ENR-NPs were uniform in size and full in shape with an average particle size of 135 nm. The encapsulation rate (76.61%) and drug loading capacity (3.3%) were measured by ultraviolet spectrophotometry . The in vitro experiments elucidated that the release rate of enrofloxacin from ENR-NPs was significantly faster at pH 5.0 than at pH 7.4 due to the cleavage of the acid-sensitive Schiff-base bond. Further, the antimicrobial studies revealed that the inhibitory effects were improved with the increase of acidity of the culture medium. Therefore, ENR-NPs provide a potential application of enrofloxacin for bacterial-response drug delivery.
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COLLOIDS AND SURFACES A-PHYSICOCHEMICAL AND ENGINEERING ASPECTS
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2021
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IF 4.539
Lirong Yang,Chuanqun Huang,Xuan Luo,Lin Zhang,Yongjie Ye,Hui Jun,Yan Wang
Due to the high swelling ratio, the use of chitosan-based composites for adsorption of U(VI) from wastewater is limited. To overcome this shortcoming, a novel type of hierarchical porous chitosan-based aerogel (CS-PTA-DMAs) with anti-swelling is successfully prepared via cross-linking chitosan with the cross-linker PTA-DMA, which is synthesized by p-phthalaldehyde (PTA) and 3,5-diaminobenzoic acid (DMA). There is no significant volume expansion of the aerogel after soaking in ultrapure water for 1 week, indicating it has good swelling property. In addition, the CS-PTA-DMA aerogel has a high U(VI) adsorption capacity of 160 mg/g (308 K, pH 6). The adsorption behavior of CS-PTA-DMA to U(VI) is coordinate to the pseudo-second-order kinetic model and Freundlich isothermal model, which is spontaneously endothermic. Moreover, the adsorption mechanism is also investigated in details. These findings are crucial for the development of practical application uranium adsorbents.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Xialian Fan,Yijin Li,Xiumin Li,Yonghui Wu,Keyong Tang,Jie Liu,Xuejing Zheng,Guangming Wan
Here an injectable antibacterial aerogel was fabricated with oxidized cellulose nanofiber and chitosan for rapid hemostasis of noncompressible hemorrhage application. Especially, cellulose nanofiber was modified with carboxyl groups by pre-oxidizing in 2,2,6,6-tetramethylpiperidine-1-oxyl combined with high pressure homogenization. Whereafter, the realized carboxyl group of cellulose nanofiber was reacted with the amidogen of chitosan to yield a strong composite aerogel with a nanofiber/nanosheet interlaced structure, which increased the compressive mechanical strength up to 75.4 kPa. In addition, the nanocellulose/chitosan composite aerogel exhibits high water absorption capacity, rapid shape recovery and good antibacterial ability (via Escherichia coli and Staphylococcus aureus ). Once absorbing water, the nanocellulose5/chitosan5 compressed aerogel could rapidly recover its shape within 30 s. The in vitro coagulation ability measurement showed that the composite aerogel has a good adhesion and aggregation effect to red blood cells and platelets. Hemolysis and cytotoxicity analysis results indicated a good biocompatibility for the composite aerogel.
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INTERNATIONAL JOURNAL OF BIOLOGICAL MACROMOLECULES
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2019
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IF 4.784
Fang Wang,Qian Zhang,Kexin Huang,Jiarui Li,Kun Wang,Kai Zhang,Xinyue Tang
The objective of this study was to synthesize and characterize cystamine dihydrochloride (CYS) crosslinked carboxymethyl cellulose/quaternized chitosan (CMC/HACC) composite hydrogel film. Firstly, the glycidyl-based quaternary ammonium chitosan derivative (HACC) was synthesized using nucleophilic substitution reaction. Then HACC was analyzed by FTIR, 1 HNMR spectra and the composite films at different blending ratio of CMC and HACC were studied by rheology measurement, mechanical and swelling tests. When the composite films were prepared under optimized conditions (CMC: HACC = 7:1), they showed excellent mechanical properties (with improved 93.3% tensile strength and 2.3% elongation at break) and swellability (equilibrium swelling ratio increased 270%) compared to pure CMC film. 5-Fluorouracil (5-FU) was used as drug model which has broad-spectrum anticancer properties. The 5-FU/CMC/HACC composite films showed redox and pH responsive of drug release properties along with well biocompatibility. The in vitro cytotoxicity and cell apoptosis studies showed the drug loaded composite films with obvious toxicity against HepG2 cells especially in the presence of GSH. In addition, CMC/HACC composite films showed good antibacterial against S. aureus and E. coli , while pure CMC film had no antimicrobial activities. It can be concluded that CMC/HACC composite films can be potentially used as targeted drug delivery system.
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AAPS PHARMSCITECH
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2019
·Vol. 20
·期 7
·1-10
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IF 2.608
Xu Yingxin,Fang Tianxu,Yang Yifan,Sun Li’ang,Shen Qi
Docetaxel (DTX) was effective in the treatment of neoplasm but could only be administered intravenously with the poor oral bioavailability owing to its undesirable solubility, remarkably metabolic conversion, and other factors. Cimetidine (CMD), a classic CYP3A4 isozyme inhibitor, had exhibited a wide range of inhibition on the metabolism of many drugs. The aim of this study was to construct the novel docetaxel-cimetidine (DTX-CMD) complex and the chitosan-deoxycholate nanoparticles based on it to confirm whether this formulation could show advantages in terms of solubility, dissolution rate, small intestinal absorption, and oral bioavailability in comparison with the pure drug. The solid-state characterization was carried out by powder X-ray diffraction (PXRD), Fourier transform infrared spectroscopy (FT-IR), and simultaneous DSC-TGA (SDT). Dissolution rate and kinetic solubility study were determined by evaluating the amount of DTX in distilled water and phosphate buffer solution (pH = 7.4), respectively. And small intestinal absorption and pharmacokinetics study were conducted in rats. The results of this study demonstrated that we successfully constructed DTX-CMD complex and its chitosan-deoxycholate nanoparticles. Furthermore, the DTX-CMD complex increased the solubility of DTX by 2.3-fold and 2.1-fold in distilled water and phosphate buffer solution, respectively. The ultimate accumulative amount of DTX-CMD complex nanoparticles through rat small intestinal in 2 h was approximately 4.9-fold and the oral bioavailability of the novel nanoparticles was enhanced 2.8-fold, compared with the pure DTX. The superior properties of the complex nanoparticles could both improve oral bioavailability and provide much more feasibility for other formulations of DTX.
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Materials Science & Engineering C-Materials for Biological Applications
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2019
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IF 4.959
Keke Wu,Xiaoyan Liu,Zhentao Li,Yanpeng Jiao,Changren Zhou
Functional chitosan/graphene oxide (CS/GO) composite aerogel microspheres were fabricated via CO 2 supercritical drying, which displayed excellent performance for bilirubin removal. The morphology and chemical structure of CS/GO composite aerogel microspheres were characterized, which illustrated a nanoporous structure with a maximum specific surface area of 174.69 m 2 /g, and a special pore size distribution at 20–40 nm, also a good mechanical property. Importantly, the composite aerogel microspheres (10% GO) revealed a large adsorption capacity (178.25 mg/g) for bilirubin within 2 h. Dynamic adsorption experiment illustrated that the aerogel microspheres adsorbed much more bilirubin with a shorter equilibrium time of about 30 min. Besides, the adsorption mechanism of bilirubin by the CS/GO composite aerogel microspheres was investigated through the relevant model fitting, including adsorption kinetics and adsorption isotherm, which illustrated that the mechanism included both physical and chemical processes, but chemical adsorption was dominated. Adsorption isotherm indicated that bilirubin adsorption by the microspheres was fitted well with Freundlich isotherm, which ascribed to multilayer adsorption. After five adsorption-desorption cycles, the adsorption capacity still maintains large adsorption capacity. In addition, the hemolysis rate and coagulation time tests presented the good blood compatibility for the adsorbents. Therefore, the CS/GO composite aerogel microspheres with rapid, high adsorption capacity and good blood compatibility might be promising for hyperbilirubinemia treatment.
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Polymers
·
2019
·Vol. 11
·期 9
·1418
·
IF 3.164
Wei Li,Kewang Zheng,Hujian Chen,Shirong Feng,Wei Wang,Caiqin Qin
The combined effects of nano titanium dioxide (TiO2-N) and clove oil (CO) on the physico-chemical, biological and structural properties of chitosan (CH)/starch (ST) films were investigated by using a solvent casting method. Results indicated that the incorporation of TiO2-N could improve the compactness of the film, increase the tensile strength (TS) and antioxidant activity, and decrease the water vapour permeability (WVP). As may be expected, the incorporation of CO into the film matrix decreased TS but increased the hydrophobicity as well as water vapour barrier antimicrobial and antioxidant properties. Fourier-transform infrared spectroscopy (FTIR) data supported intermolecular interactions between TiO2-N, CO and the film matrix. Use of a scanning electron microscope (SEM) showed that TiO2-N and CO were well dispersed and emulsified in the film network. Thermogravimetric (TG) and derivative thermogravimetric (DTG) curves demonstrated that TiO2-N and CO were well embedded in the film matrix, hence this blend film system could provide new formulation options for food packaging materials in the future.Keywords:chitosan;starch;nano titanium dioxide;clove essential oil;edible film
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Polymers
·
2019
·Vol. 11
·期 10
·1550
·
IF 3.164
Zhen Li,Shunqi Mei,Yajie Dong,Fenghua She,Lingxue Kong
While electrospinning has been widely employed to spin nanofibers, its low production rate has limited its potential for industrial applications. Comparing with electrospinning, centrifugal spinning technology is a prospective method to fabricate nanofibers with high productivity. In the current study, key parameters of the centrifugal spinning system, including concentration, rotational speed, nozzle diameter and nozzle length, were studied to control fiber diameter. An empirical model was established to determine the final diameters of nanofibers via controlling various parameters of the centrifugal spinning process. The empirical model was validated via fabrication of carboxylated chitosan (CCS) and polyethylene oxide (PEO) composite nanofibers. DSC and TGA illustrated that the thermal properties of CCS/PEO nanofibers were stable, while FTIR-ATR indicated that the chemical structures of CCS and PEO were unchanged during composite fabrication. The empirical model could provide an insight into the fabrication of nanofibers with desired uniform diameters as potential biomedical materials. This study demonstrated that centrifugal spinning could be an alternative method for the fabrication of uniform nanofibers with high yield.Keywords:carboxylated chitosan;centrifugal spinning;nanofiber diameter;empirical model
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