查找使用阿拉丁产品的科研文献

Schiff base functionalized chitosan anion exchange membranes with 1,4-dichlorobutane as the crosslinker

Xu Han,XuYing Zheng,Shiyang Song,Jilin Wang,Lulu Wang

A series of composite membranes (CS-PY-DL x ) were synthesized by using schiff base functionalized chitosan (CS-PY) as the polymer matrix, 1,4-dichlorobutane (DL) as the crosslinker, the quaternization reagent is iodomethane . In this work, pyridine groups grafted on chitosan were converted into quaternary ammonium salt while forming cross-linked network structure. The FT-IR shows that the CS-PY-DL x membranes has been successfully prepared. The introduction of cross-linked structure enhances the alkali resistance, thermal stability and other properties of CS-PY-DL x membranes. When the cross-linked degree is 25%, the anion exchange membrane had the maximum tensile strength (24.45 MPa), and the anionic conductivity reaches 7.08 × 10 −3  S cm −1 at 70 °C. The alkali resistance test was researched under the condition of 3 mol L −1 KOH solution for 120 h at 80 °C, which showed that the OH − conductivity of CS-PY-DL 25 membranes retains approximately 79.7% of its initial conductivity, revealing the excellent alkali resistance. Methanol permeability was only 0.37–0.72% of the Nafion-117 membrane in 3M methanol at 60 °C, indicating an excellent resistance to alcohol.

Biosorptive removal of cobalt(II) from aqueous solutions using magnetic cyanoethyl chitosan beads

Qian Zhang,Shuting Zhuang,Jianlong Wang

Biosorption is a cleaner technology for the treatment of heavy metal-containing wastewater. In this study, a cleaner method was proposed for preparing a novel biosorbent, magnetic cyanoethyl chitosan beads, which was characterized by FT-IR, SEM-EDS, XRD, TGA, BET, and vibrating sample magnetometer, and applied for removing Co 2+ from aqueous solutions. The influencing factors, such as contact time (0−120 min), pH (5–8), and initial concentration of cobalt ions (10−600 mg L −1 ), were examined. The first-order, second-order, intraparticle diffusion, and Elovich models were used to simulate the kinetics of the cobalt adsorption process. The experimental data of isotherms were analyzed by the Langmuir, Freundlich, and Temkin models. Among them, the second-order model and Langmuir model were the best fitting. The adsorption capacity was calculated to be 17.92 mg g −1 according to the Langmuir model. From the analysis of the FT-IR spectra, it can be inferred that CN and NH 2 were mainly responsible for the adsorption of Co 2+ from aqueous solutions. The grafting of cyanoethyl groups on chitosan enhanced the sorption capacity towards Co 2+ , the magnetic cyanoethyl chitosan bead is economical and effective biosorbent for the treatment heavy metal-containing wastewater.

Removal of Cd(II) from aqueous solution using cross-linked chitosan–zeolite composite

Feng Zhang,Manman Wang,Limei Zhou,Xiaoyan Ma,Yafen Zhou

Cross-linked chitosan–zeolite composite was prepared and characterized by Fourier transform infrared spectroscopy and scanning electron microscope. Adsorption of Cd(II) by the cross-linked chitosan–zeolite composite as a function of solution pH, contact time, initial Cd(II) concentration, and temperature was investigated systematically by batch experiments. The obtained results showed that the removal of Cd(II) was pH dependent and the optimum adsorption was achieved at pH 7.0. The adsorption process could be described by pseudo-second-order kinetic model. Thermodynamic parameters revealed the spontaneous and endothermic nature of the adsorption. The batch adsorption data could be well elucidated by the Langmuir model. The maximum adsorption capacity of Cd(II) on the cross-linked chitosan–zeolite composite at 25°C determined from the Langmuir model was 102.15 mg/g. The adsorbent was successfully regenerated using EDTA, HNO3, and HCl solution as desorbent, respectively.

Neodymium Modified Chitosan/PMMA Integrated Thin-Core Fiber for Trace Fluoride Ion Detection

Yi Jiang,Hongliang Chen,Xiaozhan Yang,Wenlin Feng

Preparation, Characterization, and Biochemical Activities of N-(2-Carboxyethyl)chitosan from Squid Pens

Jun Huang,Haihua Xie,Sheng Hu,Tian Xie,Jinyan Gong,Chengjun Jiang,Qing Ge,Yuanfeng Wu,Shiwang Liu,Yanli Cui,Jianwei Mao,Lehe Mei

Chitosan was prepared by alkaline N-deacetylation of β-chitin from squid pens, and N-carboxyethylated derivatives (N-CECS) with different degrees of substitution (DS) were synthesized. The carboxyethylation of the polysaccharide was identified by Fourier transform infrared, 1H and 13C nuclear magnetic resonance (NMR), and X-ray diffraction analyses. The DS of the derivatives was calculated by 1H NMR and elemental analysis. All three N-CECS samples showed good water solubility at pH > 6.5. The antioxidant properties and bile acid binding capacity of the derivatives were studied in vitro. The highest bile acid binding capacity of all N-CECS reached 36.9 mg/g, which was 2.6-fold higher than that of chitosan. N-CECS showed a stronger scavenging effect on 2,2′-azinobis(3-ethylbenzothiazoline-6-sulfonic acid) radical ability, and EC50 values were below 2 mg/mL. The scavenging ability of N-CECS against superoxide radicals correlated well with the DS and concentration of N-CECS. These results indicated that N-carboxyethylation is a possible approach to prepare chitosan derivatives with desirable in vitro biochemical properties.

Dissolution and regeneration behavior of chitosan in 3-methyl-1-(ethylacetyl)imidazolium chloride

Xu Bin,Li Qiaoping,Zhuang Linghua,Wang Qiang,Li Chao,Wang Guowei,Xie Fengwei,Halley Peter J.

3-methyl-1-(ethylacetyl)imidazolium chloride ([EtMIM]Cl), was synthesized for chitosan dissolution, and the dissolution and regeneration behaviors of chitosan in [EtMIM]Cl were thoroughly investigated. The solubility of chitosan in [EtMIM]Cl was measured at temperatures ranging from 40 °C to 110 °C, based on which the thermodynamic parameters of chitosan in [EtMIM]Cl were calculated. The polarizability and hydrogen bond accepting ability was determined by solvatochromic UV/vis spectroscopy. The regenerated chitosan from [EtMIM]Cl by adding methanol was characterized by thermogravimetric analysis (TGA), Fourier transform infrared spectroscopy (FTIR), X-ray diffraction (XRD) and scanning electron microscopy (SEM). Density functional theory (DFT) computations were performed to study the interactions between [EtMIM]Cl and chitobiose. Five kinds of hydrogen bonds, C-H/O, O-H/O, O-H/Cl, C-H/Cl, N-H/Cl were found, suggesting strong interactions between [EtMIM]Cl and chitobiose. In particular, the oxygen atom and the active methylene group of carboxylic ester in [EtMIM] + , formed strong hydrogen bonding with chitobiose. The molecular simulation results indicated that both the Cl − anions and [EtMIM] + cation played important roles in the chitosan dissolution process, by the disruption of native hydrogen bonds of chitosan.

Synthesis and characterization of fluorescent chitosan–ZnSe/ZnS nanoparticles for potential drug carriers

Yeping Li,Jingbo Xu,Yun Xu,Liying Huang,Junli Wang,Xiaonong Cheng

The objective of the study is to describe a new approach of combining quantum dots into chitosan as an anti-cancer drug carrier. Novel chitosan–ZnSe/ZnS (CS–ZnSe/ZnS) nanoparticles were synthesized by a one-step ionic gelation technique, with ZnSe/ZnS quantum dots (ZnSe/ZnS QDs) as cross-linking agent and for fluorescent labeling. The approach not only avoids the use of emulsifiers and chemical cross-linking agents but also prevents the possibility of damage to drugs. The fluorescent CS–ZnSe/ZnS nanoparticles were about 100–500 nm in size and stable in a physiological environment. Low cytotoxicity was ensured by investigation with mouse lung carcinoma cells. The cell viability remained 99% when the concentration of CS–ZnSe/ZnS nanoparticles increased to 200 μg mL−1. In the in vitro drug release experiment, 5-fluorouracil (5-Fu) loaded within CS–ZnSe/ZnS nanoparticles had more preferable sustained-release performance and longer equilibrium time compared with that of the pure 5-Fu. The fluorescent CS–ZnSe/ZnS nanoparticles are expected to be used for biological fluorescent labeling and drug carriers.

Chitosan Oligosaccharide Modified Bovine Serum Albumin Nanoparticles for Improving Oral Bioavailability of Naringenin

Fang Ruiyue,Liao Yiqi,Qiu Huishuang,Liu Yuxin,Lin Shiyuan,Chen Hui

Introduction: With the rapid development of nanotechnology, the research and development of nano-drugs have become one of the development directions of drug innovation. The encapsulation of the nanoparticles can change the biological distribution of the drug in vivo and improve the bioavailability of the drug in vivo. Naringenin is poorly soluble in water and has a low bioavailability, thus limiting its clinical application. The main purpose of this study was to develop a nano-sized preparation that could improve the oral bioavailability of naringenin. Methods: Chitosan oligosaccharide modified naringenin-loaded bovine serum albumin nanoparticles (BSA-COS@Nar NPs) were prepared by emulsification solvent evaporation and electrostatic interaction. The nanoparticles were characterized by HPLC, laser particle size analyzer, transmission electron microscope and X-ray diffraction analysis. The release in vitro was investigated, and the behavior of nanoparticles in rats was also studied. The caco-2 cell model was established in vitro to investigate the cytotoxicity and cellular uptake of nanoparticles. Results: BSA-COS@Nar NPs were successfully prepared, and the first-order release model was confirmed in vitro release. In vivo pharmacokinetic results indicated that the area under the drug concentration- time curve (AUC) of BSA-COS@Nar NPs was 2.37 times more than free naringenin. Cytotoxicity and cellular uptake results showed that BSA-COS@Nar NPs had no significant cytotoxic effect on Caco- 2 cells and promoted cellular uptake of the drug. Conclusion: BSA-COS@Nar NPs could improve the in vivo bioavailability of naringenin.

Preparation of Fluorescently Labeled Chitosan-Quercetin Drug-Loaded Nanoparticles with Excellent Antibacterial Properties

Jingxin Zhou,Na Li,Ping Liu,Zhiwei Liu,Lili Gao,Tifeng Jiao

In recent years, quercetin plays an increasingly important role in the medical field. However, the absorption and effect of quercetin as a drug in vivo are limited due to its extremely poor solubility in water. In addition, chitosan nanoparticles can deliver poorly soluble drugs as drug delivery carriers. Herein, chitosan nanoparticles were prepared by oxidative degradation and ionic cross-linking technology to study the drug loading properties of quercetin. On the other hand, the application of chitosan for fluorescent materials can improve the biocompatibility of fluorescent materials and increase the adsorption of fluorescent materials. Fluorescently labeled chitosan nanoparticles, especially chitosan microsphere fluorescent probes prepared using the abundant amino groups on chitosan chains to react with fluorescein isothiocyanate (FTIC), have been widely used as fluorescent probes in biomarkers and medical diagnostics. Therefore, chitosan–quercetin (CS–QT) drug-loaded nanoparticles are labeled with FITC, and the drug-loaded rate, encapsulation efficiency, and antioxidant properties were investigated. The drug-loaded rate of the sample reaches 8.39%, the encapsulation rate reaches 83.65%, and exhibits good antioxidant capacity. The fluorescence aperture of the obtained sample was consistent with the inhibition zone, which could realize the visualization of the antibacterial performance of the sample. The fluorescent-labeled nano-system exhibit superior antibacterial properties, which provide a strategy for observing the release and function of drugs.

Adsorption of hexavalent chromium by novel chitosan/poly(ethylene oxide)/permutit electrospun nanofibers

Panpan Wang,Lihua Wang,Shujun Dong,Guohui Zhang,Xuejuan Shi,Chunhui Xiang,Lili Li

Chitosan/poly(ethylene oxide)/permutit (CS/PEO/PT) composite nanofibers were prepared via electrospinning and their potential application in the removal of hexavalent chromium (Cr(VI)) from aqueous solutions was studied in detail. SEM results showed that the nanofibers were homogeneous and bead-free. XRD and DSC results demonstrated that there were strong interactions among CS, PEO and PT. The solubility test showed that the CS/PEO/PT composite membrane had excellent durability in water. The CS/PEO/PT-1% nanofibers exhibited the best adsorption performance for Cr(VI) ions in acidic solution (pH = 3) and at a low Cr(VI) concentration of 50 mg L−1. The maximum adsorption capacity reached 208 mg g−1. The adsorption kinetics and equilibrium data were well described by pseudo-second-order kinetic and Langmuir isotherm models, respectively. According to the results of FTIR and XPS analyses, protonation, ion exchange, electrostatic interactions and redox reactions were involved in the adsorption process. All the results indicated that the electrospun CS/PEO/PT nanofibers could be used as promising absorbents for the removal of Cr(VI).

Simultaneous adsorption of aniline and Cr(VI) ion by activated carbon/chitosan composite

Ruihua Huang,Bingchao Yang,Qian Liu,Yanping Liu

Activated carbon/chitosan composite has been used as an adsorbent to remove aniline and Cr(VI) ions from aqueous solutions simultaneously. The effects of preparation conditions such as the ratio of activated carbon to chitosan, crosslinking reagents, crosslinking time, and adsorption conditions including adsorbent dosage, pH value of solution, and contact time on simultaneous adsorption of aniline and Cr(VI) ion were investigated. Experimental results showed that epichlorohydrin was the proper crosslinking reagent, and the ratio of activated carbon to chitosan was kept at 1. When the adsorbent dosage was 4.0 g/L, and the concentrations of aniline and Cr(VI) were lower than 50 and 100 mg/L, respectively, both aniline and Cr(VI) were simultaneously removed at natural pH with high removals (>95%). The presence of Cr(VI) enhanced the adsorption of aniline, while the presence of aniline almost had no influence on the adsorption of Cr(VI). The adsorption processes of both aniline and Cr(VI) followed the pseudo-second-order kinetics model, but the sorption of Cr(VI) was preferential to that of aniline by this composite. © 2013 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131 , 39903.

Durable Zwitterionic Hydrogel Coating Reinforced with Chitosan Microspheres for Bone Fracture Fixation Devices

Zhijie Zhao,Yingying Meng,Yao Shu,Yunfeng Yi,Junjie Li,Yuping Wei

The bone fixation implants in the clinic are prone to inflammation and thrombosis that result in efficacy and patient health risks. This paper introduces chitosan microsphere-enhanced poly(sulfobetaine) (CSM/PSBMA) zwitterionic hydrogel coated on the surface of polylactic acid (PLA) fracture fixation devices through interfacial autocatalytic polymerization and in situ gelation. CSM as a disperse phase improves both the mechanical strength and swelling resistance of the PSBMA matrix of the continuous phase. The CSM/PSBMA hydrogel coating keeps the superhydrophilicity and excellent antifouling properties of the pure PSBMA hydrogel coating. In particular, the CSM/PSBMA hydrogel coating still exhibits good stability after 30 days of PBS immersion, 7 days of PBS shearing, 30 min of PBS ultrasonication, and 30 min of water flushing. Furthermore, the CSM/PSBMA hydrogel-coated PLA implants can alleviate foreign body reaction and accelerate the bone repair in the rat femoral fracture model. This brings a promising path for devising zwitterionic hydrogel coatings for implantable medical devices.