In the process of exploration and development of oil and gas fields, the acidic environment of oil reservoir, production and transport processes cause corrosion of pipelines and equipment, resulting in huge economic l...In the process of exploration and development of oil and gas fields, the acidic environment of oil reservoir, production and transport processes cause corrosion of pipelines and equipment, resulting in huge economic losses and production safety risks. Corrosion inhibitors were widely used in oil industry because of simple operation process and economical. In this study, three environmentally friendly corrosion inhibitors were synthesized based on the natural polysaccharide chitosan. Corrosion inhibition of three dendritic chitosan derivatives (We name them BH, CH and DH) on mild steel in 1 mol/L HCl solution with natural ventilation system was evaluated by weight loss experiment, electrochemical analysis and surface morphology characterization. The experimental results showed that when the three dendritic chitosan derivatives added in the corrosive medium were 500 mg L^(−1), the corrosion inhibition efficiencies were all more than 80%. Based on quantum chemical calculation, inhibition mechanisms of three dendritic chitosan derivatives were investigated according to molecular structures. The results showed that the benzene ring, Schiff base and N atom contained in the molecule were the active centers of electron exchange, which were more likely to form a film on the carbon steel surface, thereby slowing or inhibiting corrosion. The results also predicted the corrosion inhibition effect BH > DH > CH, which was consistent with the experimental conclusion.展开更多
Supercapacitors(SCs)with high power output have attracted increasing attention as efficient and environmentally friendly energy storage devices.Prussian blue and its analogues(PB/PBAs)are simple coordination polymers ...Supercapacitors(SCs)with high power output have attracted increasing attention as efficient and environmentally friendly energy storage devices.Prussian blue and its analogues(PB/PBAs)are simple coordination polymers with tunable chemical compositions and open framework.Prussian blue can act as electrode materials in its pristine form and has also been utilized to derive various metallic nanostructures for electrochemical applications due to their simple fabrication process,non-toxic characteristics,and low price.Here,we firstly describe the charge storage mechanisms of SCs briefly followed by an introduction of the fabrication methods of PB/PBAs and their derivatives.Then,a comprehensive review on recent studies of the use of PB/PBAs and their derivatives as the electrode materials for SCs are given with a focus on strategies to improve their electrochemical performances.Finally,we discuss critical challenges in this research area and propose some general ideas for future research.展开更多
The study examined the adsorption of Pb(II) ions from aqueous solution onto chitosan, chitosan-GLA and chitosan-alginate beads. Several important parameters influencing the adsorption of Pb(II) ions such as initia...The study examined the adsorption of Pb(II) ions from aqueous solution onto chitosan, chitosan-GLA and chitosan-alginate beads. Several important parameters influencing the adsorption of Pb(II) ions such as initial pH, adsorbent dosage and different initial concentration of Pb(II) ions were evaluated. The mechanism involved during the adsorption process was explored based on ion exchange study and using spectroscopic techniques. The adsorption capacities obtained based on non–linear Langmuir isotherm for chitosan, chitosan-GLA and chitosan-alginate beads in single metal system were 34.98, 14.24 and 60.27 mg/g, respectively. However, the adsorption capacity of Pb(II) ions were reduced in the binary metal system due to the competitive adsorption between Pb(II) and Cu(II) ions. Based on the ion exchange study, the release of Ca2+, Mg2+, K+ and Na+ ions played an important role in the adsorption of Pb(II) ions by all three adsorbents but only at lower concentrations of Pb(II) ions. Infrared spectra showed that the binding between Pb(II) ions and the adsorbents involved mostly the nitrogen and oxygen atoms. All three adsorbents showed satisfactory adsorption capacities and can be considered as an efficient adsorbent for the removal of Pb(II) ions from aqueous solutions.展开更多
Chitosan composites and derivatives have gained wide attentions as effective biosorbents due to their low costs and high contents of amino and hydroxyl functional groups.They have showed significant potentials of remo...Chitosan composites and derivatives have gained wide attentions as effective biosorbents due to their low costs and high contents of amino and hydroxyl functional groups.They have showed significant potentials of removing metal ions,dyes and proteins from various media.Chemical modifications that lead to the formation of the chitosan derivatives and chitosan composites have been extensively studied and widely reported in literatures.The aims of this review were to summarize the important information of the bioactivities of chitosan,highlight the various preparation methods of chitosan-based active biosorbents,and outline its potential applications in the adsorption of heavy metal ions,dyes and proteins from wastewater and aqueous solutions.展开更多
Prussian blue analogues(PBAs) with inherent ordered structures and abundant metal ion sites are widely explored as precursors for various electrochemical applications,including oxygen evolution reaction(OER).Using a r...Prussian blue analogues(PBAs) with inherent ordered structures and abundant metal ion sites are widely explored as precursors for various electrochemical applications,including oxygen evolution reaction(OER).Using a range of characterization techniques including Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and energy dispersive spectroscopy(EDS),this work discloses the process of replacement of K^(+)by NH4^(+)in the interstitial spaces of the CoFe PBA by a hot aqueous urea solution,which influences the transformation of PBAs under further heat treatment and the OER performance of the deriva tives.After heat treatment at 400℃ under Ar flow,high-resolution transmission electron microscopy(HRTEM) images reveal that CoFe alloy nanoparticles grew on the crystalline cubes of CoFe PBA with K^(+),while CoFe PBA cubes with NH4^(+)become amorphous.Besides,the derivative of CoFe PBA with NH4^(+)(Ar-U-CoFe PBA) performs better than the derivative of CoFe PBA with K^(+)(Ar-CoFe PBA) in OER,registering a lower overpotential of 305 mV at 10 mA cm^(-2),a smaller Tafel slope of 36.1 mV dec^(-1),and better stability over a testing course of 20 h in 1.0 M KOH.A single-cell alkaline electrolyzer,using Ar-U-CoFe PBA and Pt/C for the anodic and cathodic catalyst,respectively,requires an initial cell voltage of 1.66 V to achieve 100 mA cm^(-2)at 80℃,with negligible degradation after100 h.展开更多
Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivat...Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quatemized chitosan derivatives are favorable adsorbents for bile acid.展开更多
Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan,...Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two N-substituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three O-substituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.展开更多
The adsorption of Fe(Ⅲ)ions from aqueous solution by chitosan alpha-ketoglutaric acid(KCTS)and hydroxamated chitosan alpha-ketoglutaric acid(HKCTS)was studied in a batch adsorption system.Experiments were carried out...The adsorption of Fe(Ⅲ)ions from aqueous solution by chitosan alpha-ketoglutaric acid(KCTS)and hydroxamated chitosan alpha-ketoglutaric acid(HKCTS)was studied in a batch adsorption system.Experiments were carried out as function of pH,temperature,agitation rate and concentration of Fe(Ⅲ)ions.The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and isotherm constants were determined.The Langmuir model agrees very well with experimental data.The pseudo-first-order a...展开更多
To improve the solubility and bioactivity of chitosan,a new class of carboxymethyl chitosan derivatives possessing sulfonium salts was successfully designed and synthesized,including Methyl sulfi de carboxymethyl chit...To improve the solubility and bioactivity of chitosan,a new class of carboxymethyl chitosan derivatives possessing sulfonium salts was successfully designed and synthesized,including Methyl sulfi de carboxymethyl chitosan(MCMCS),Ethyl sulfi de carboxymethyl chitosan(ECMCS),Propyl sulfi de carboxymethyl chitosan(PCMCS),and Butyl sulfi de carboxymethyl chitosan(BCMCS).To determine the structure of the new class of the derivatives,methods of the Fourier transform infrared spectroscopy(FT-IR),^(1)H nuclear magnetic resonance spectrometer(^(1)H NMR),and^(13)C nuclear magnetic resonance spectrometer(^(13)C NMR)were used.Moreover,the antioxidant activity of the derivatives for three types of free radicals,i.e.,hydroxyl radical,superoxide radical,and 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical was evaluated in vitro.In addition,the L929 cells were adopted to test the cytotoxicity of chitosan and its derivatives by CCK-8 assay.The class of the carboxymethyl chitosan derivatives showed a strong scavenging ability against the three free radicals at 1.6 mg/mL,with scavenging rate of over 70%and some up to 100%.At this high rate,the overall cell viability in the toxicity test reached more than 80%,indicating that the synthetic derivative had a little cytotoxicity.The results show that the introduction of carboxymethyl group to chitosan increased the water-solubility of chitosan,and the combination of sulfonate ions with diff erent chain lengths further enhanced the antioxidant activity of chitosan.Therefore,the sulfonium-containing carboxymethyl chitosan derivatives had excellent bioactivity with good application prospects in food,biomedicine,and medical fi elds.展开更多
Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wista...Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-α in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.展开更多
Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative(CHMMs) were prepared by inverse suspension method,and used for the methyl orange(MO) removal from aqueous solutions...Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative(CHMMs) were prepared by inverse suspension method,and used for the methyl orange(MO) removal from aqueous solutions.The CHMMs were characterized by a scanning electron microscope,a transmission electron microscope,and Fourier transform infrared spectroscopy,respectively.Compared with the chitosan beads,the incorporation of quaternary ammonium chitosan derivative significantly reduced the particle size.The MO adsorption by CHMMs was investigated by batch adsorption experiments.The adsorption kinetics was conformed to the pseudo second-order kinetics equation.The adsorption isotherm followed the Langmuir model better than the Freundlich model and the calculated maximum MO adsorption capacity was 266.6 mg·g^-1 at 293 K.Thermodynamic studies indicated that the MO adsorption was endothermic in nature with the enthalpy change(△H°) of 99.44 kJ·mol^-1.The CHMMs had a stable performance for MO adsorption in the pH range of 4-10,but high ionic strength deteriorated the MO removal due to the shielding of the ion exchange interaction.A 1 mol·L^-1 NaCl solution could be used to regenerate the exhausted CHMMs.The proposed CHMMs can be used as an effective adsorbent for dye removal or recovery from the dye wastewater.展开更多
A new chitosan derivative is prepared using chitosan.Ethyl chlorocarbonate was first introduced to the hydroxyl group of phthaloylchitosan through a nucleophilic reaction.Hydrazine was then added to recover the amino ...A new chitosan derivative is prepared using chitosan.Ethyl chlorocarbonate was first introduced to the hydroxyl group of phthaloylchitosan through a nucleophilic reaction.Hydrazine was then added to recover the amino groups of chitosan and promote cross-linking.The structure of this new chitosan derivative was characterized by Fourier transform infrared(FT-IR)and proton nuclear magnetic resonance(1H NMR)spectroscopy,and its physical properties were determined by X-ray diffraction(XRD),differential scanning calorimetry(DSC),and thermogravimetric analysis(TGA).The thermal and chemical stabilities of the new derivative were improved compared with those of native chitosan.Assay of Escherichia coli adhesion on a film based on this chitosan derivative showed good adsorption and biofilm formation.展开更多
The reaction of 1-methylisoquinoline 1 with hy-drazonoyl halides 2 in ethanol in the presence of chitosan under microwave irradiation affords triazoloisoquinoline 4. Product 4 reacts with dimethylformamide-dimethylace...The reaction of 1-methylisoquinoline 1 with hy-drazonoyl halides 2 in ethanol in the presence of chitosan under microwave irradiation affords triazoloisoquinoline 4. Product 4 reacts with dimethylformamide-dimethylacetal to give ena- minones 7 which react with hydrazonoyl halides to give pyrazolyl triazoloisoquinoline 13. Also, 1-methylisoquinoline 1 reacts with arylisothio-cyanate to give thioanilide 15 which reacts with hydrazonoyl halides to give the corresponding thiadiazolyl isoquinoline derivatives 20, 24.展开更多
An amphiphilic N-octyl-O-methoxy poly (ethylene glycol) chitosan was successfully prepared by grafting successively octyl groups onto amino groups at chitosan’s C-2 position as hydrophobic moieties and methoxy polyet...An amphiphilic N-octyl-O-methoxy poly (ethylene glycol) chitosan was successfully prepared by grafting successively octyl groups onto amino groups at chitosan’s C-2 position as hydrophobic moieties and methoxy polyethylene glycol (MPEG) groups onto hydroxyl groups at C-6, C-3 as hy-drophilic ones. A certain amount of -NH2 was retained in the structure of chitosan derivatives through protection by phthalic anhydride. The chemical structures and degree of N-and O-substitution of chitosan derivatives were characterized by FTIR, 1H NMR, GPC and elemental analysis, respectively. The amphiphilic property for convenient self-assembly and the preserved -NH2 groups for progressive chemical cross-linking make the resultant Nocyl-O-MPEG chitosan soluble in water and potentially applicable in preparing stable chitosan hollow microspheres, a demanding drug-carrier in medical and pharmaceutical sciences.展开更多
背景:作为天然生物材料壳聚糖的一种衍生物,羧甲基壳聚糖具有独特的水溶性、成膜性、缓释性,在组织工程领域具有广阔的应用前景。目的:综述羧甲基壳聚糖相较于壳聚糖的优势以及在口腔组织再生方面的应用。方法:利用计算机检索PubMed、...背景:作为天然生物材料壳聚糖的一种衍生物,羧甲基壳聚糖具有独特的水溶性、成膜性、缓释性,在组织工程领域具有广阔的应用前景。目的:综述羧甲基壳聚糖相较于壳聚糖的优势以及在口腔组织再生方面的应用。方法:利用计算机检索PubMed、中国知网数据库相关文献,中文检索词“羧甲基壳聚糖AND组织工程,羧甲基壳聚糖AND口腔医学”,英文检索词“carboxymethyl chitosan AND tissue engineering,carboxymethyl chitosan AND(dentistry OR stomatology)”,检索时限为2006年1月至2021年10月,通过阅读和分析文献进行初步筛选,以排除重复文献和低相关性文献,最终纳入文献51篇进行结果分析。结果与结论:羧甲基壳聚糖作为一种具有良好生物相容性、可降解的无毒材料,在骨组织再生、牙体组织再生、牙周组织再生方面已取得理想的进展。羧甲基壳聚糖相比壳聚糖具有更好的水溶性、成膜性和离子结合性,这极大扩展了其在口腔组织工程的应用。羧甲基壳聚糖单独使用可发挥抗菌效果,促细胞增殖、分化,或是作为支架材料、水凝胶、改性材料与生物活性成分和生长因子联合使用均达到了预期的实验效果。展开更多
文摘In the process of exploration and development of oil and gas fields, the acidic environment of oil reservoir, production and transport processes cause corrosion of pipelines and equipment, resulting in huge economic losses and production safety risks. Corrosion inhibitors were widely used in oil industry because of simple operation process and economical. In this study, three environmentally friendly corrosion inhibitors were synthesized based on the natural polysaccharide chitosan. Corrosion inhibition of three dendritic chitosan derivatives (We name them BH, CH and DH) on mild steel in 1 mol/L HCl solution with natural ventilation system was evaluated by weight loss experiment, electrochemical analysis and surface morphology characterization. The experimental results showed that when the three dendritic chitosan derivatives added in the corrosive medium were 500 mg L^(−1), the corrosion inhibition efficiencies were all more than 80%. Based on quantum chemical calculation, inhibition mechanisms of three dendritic chitosan derivatives were investigated according to molecular structures. The results showed that the benzene ring, Schiff base and N atom contained in the molecule were the active centers of electron exchange, which were more likely to form a film on the carbon steel surface, thereby slowing or inhibiting corrosion. The results also predicted the corrosion inhibition effect BH > DH > CH, which was consistent with the experimental conclusion.
基金supported by the National Natural Science Foundation of China(Nos.51672055,51972342,51872656,and 51702275)Taishan Scholar Project of Shandong Province(ts20190922)Key Basic Research Project of Natural Science Foundation of Shandong Province(ZR2019ZD51)
文摘Supercapacitors(SCs)with high power output have attracted increasing attention as efficient and environmentally friendly energy storage devices.Prussian blue and its analogues(PB/PBAs)are simple coordination polymers with tunable chemical compositions and open framework.Prussian blue can act as electrode materials in its pristine form and has also been utilized to derive various metallic nanostructures for electrochemical applications due to their simple fabrication process,non-toxic characteristics,and low price.Here,we firstly describe the charge storage mechanisms of SCs briefly followed by an introduction of the fabrication methods of PB/PBAs and their derivatives.Then,a comprehensive review on recent studies of the use of PB/PBAs and their derivatives as the electrode materials for SCs are given with a focus on strategies to improve their electrochemical performances.Finally,we discuss critical challenges in this research area and propose some general ideas for future research.
基金the financial support under the Short Term Grant (No.304/PKIMIA/636065)
文摘The study examined the adsorption of Pb(II) ions from aqueous solution onto chitosan, chitosan-GLA and chitosan-alginate beads. Several important parameters influencing the adsorption of Pb(II) ions such as initial pH, adsorbent dosage and different initial concentration of Pb(II) ions were evaluated. The mechanism involved during the adsorption process was explored based on ion exchange study and using spectroscopic techniques. The adsorption capacities obtained based on non–linear Langmuir isotherm for chitosan, chitosan-GLA and chitosan-alginate beads in single metal system were 34.98, 14.24 and 60.27 mg/g, respectively. However, the adsorption capacity of Pb(II) ions were reduced in the binary metal system due to the competitive adsorption between Pb(II) and Cu(II) ions. Based on the ion exchange study, the release of Ca2+, Mg2+, K+ and Na+ ions played an important role in the adsorption of Pb(II) ions by all three adsorbents but only at lower concentrations of Pb(II) ions. Infrared spectra showed that the binding between Pb(II) ions and the adsorbents involved mostly the nitrogen and oxygen atoms. All three adsorbents showed satisfactory adsorption capacities and can be considered as an efficient adsorbent for the removal of Pb(II) ions from aqueous solutions.
基金financially supported by Ocean Public Welfare Scientific Research Special Appropriation Project(201005020)Fundamental Research Funds for the Central Universities and Program for Changjiang Scholars and Innovative Research Team in University(IRT1188)
文摘Chitosan composites and derivatives have gained wide attentions as effective biosorbents due to their low costs and high contents of amino and hydroxyl functional groups.They have showed significant potentials of removing metal ions,dyes and proteins from various media.Chemical modifications that lead to the formation of the chitosan derivatives and chitosan composites have been extensively studied and widely reported in literatures.The aims of this review were to summarize the important information of the bioactivities of chitosan,highlight the various preparation methods of chitosan-based active biosorbents,and outline its potential applications in the adsorption of heavy metal ions,dyes and proteins from wastewater and aqueous solutions.
基金Financial support from the China Scholarship Council(201806220068,201806650009) to F.Dthe Villum Experiment(grant No.35844) to X.X.
文摘Prussian blue analogues(PBAs) with inherent ordered structures and abundant metal ion sites are widely explored as precursors for various electrochemical applications,including oxygen evolution reaction(OER).Using a range of characterization techniques including Fourier-transform infrared spectroscopy(FT-IR),X-ray photoelectron spectroscopy(XPS),X-ray diffraction(XRD) and energy dispersive spectroscopy(EDS),this work discloses the process of replacement of K^(+)by NH4^(+)in the interstitial spaces of the CoFe PBA by a hot aqueous urea solution,which influences the transformation of PBAs under further heat treatment and the OER performance of the deriva tives.After heat treatment at 400℃ under Ar flow,high-resolution transmission electron microscopy(HRTEM) images reveal that CoFe alloy nanoparticles grew on the crystalline cubes of CoFe PBA with K^(+),while CoFe PBA cubes with NH4^(+)become amorphous.Besides,the derivative of CoFe PBA with NH4^(+)(Ar-U-CoFe PBA) performs better than the derivative of CoFe PBA with K^(+)(Ar-CoFe PBA) in OER,registering a lower overpotential of 305 mV at 10 mA cm^(-2),a smaller Tafel slope of 36.1 mV dec^(-1),and better stability over a testing course of 20 h in 1.0 M KOH.A single-cell alkaline electrolyzer,using Ar-U-CoFe PBA and Pt/C for the anodic and cathodic catalyst,respectively,requires an initial cell voltage of 1.66 V to achieve 100 mA cm^(-2)at 80℃,with negligible degradation after100 h.
基金This project is supported by the Natural Science Foundation of Tianjin (No. 043610611)
文摘Three quatemized chitosan derivatives were synthesized and their adsorption performance of bile acid from aqueous solution was studied. The adsorption capacities and rates of bile acid onto quatemized chitosan derivatives were evaluated. The kinetic experimental data properly correlated with the second-order kinetic model, which indicated that the chemical sorption is the rate-limiting step. The results showed that the quatemized chitosan derivatives are favorable adsorbents for bile acid.
基金Financial support by Laboratory of Cellulose and Lignocellulosics Chemistry, Academia Sinica
文摘Five chitosan derivatives, i.e. O-butyryl chitosan, O-benzoyl chitosan, N-phthaloyl chitosan, N-maleoyl chitosan and O-cyanoethyl chitosan, were prepared from chitosan. All of them had better solubility than chitosan, and demonstrated lyotropic liquid crystalline behavior in various solvents. The critical liquid crystalline behavior of three O-substituted chitosan derivatives was evidently different from two N-substituted analogues. Typical fingerprint textures of cholesteric phase were only observed in three O-substituted derivatives. The critical concentration (v/v%) of three O-substituted derivatives does not depend on the acidity of acidic solvents.
基金This work was financially supported by the National Science Foundation of China(No.20376085).
文摘The adsorption of Fe(Ⅲ)ions from aqueous solution by chitosan alpha-ketoglutaric acid(KCTS)and hydroxamated chitosan alpha-ketoglutaric acid(HKCTS)was studied in a batch adsorption system.Experiments were carried out as function of pH,temperature,agitation rate and concentration of Fe(Ⅲ)ions.The Langmuir and Freundlich adsorption models were applied to describe the equilibrium isotherms and isotherm constants were determined.The Langmuir model agrees very well with experimental data.The pseudo-first-order a...
基金Supported by the National Key R&D Program of China(No.2019YFD0900705)the Key Deployment Projects of the Marine Science Research Center of the Chinese Academy of Sciences(No.COMS2020J04)the Natural Science Foundation of Shandong Province of China(No.ZR2019BD064)。
文摘To improve the solubility and bioactivity of chitosan,a new class of carboxymethyl chitosan derivatives possessing sulfonium salts was successfully designed and synthesized,including Methyl sulfi de carboxymethyl chitosan(MCMCS),Ethyl sulfi de carboxymethyl chitosan(ECMCS),Propyl sulfi de carboxymethyl chitosan(PCMCS),and Butyl sulfi de carboxymethyl chitosan(BCMCS).To determine the structure of the new class of the derivatives,methods of the Fourier transform infrared spectroscopy(FT-IR),^(1)H nuclear magnetic resonance spectrometer(^(1)H NMR),and^(13)C nuclear magnetic resonance spectrometer(^(13)C NMR)were used.Moreover,the antioxidant activity of the derivatives for three types of free radicals,i.e.,hydroxyl radical,superoxide radical,and 1,1-diphenyl-2-picrylhydrazyl(DPPH)radical was evaluated in vitro.In addition,the L929 cells were adopted to test the cytotoxicity of chitosan and its derivatives by CCK-8 assay.The class of the carboxymethyl chitosan derivatives showed a strong scavenging ability against the three free radicals at 1.6 mg/mL,with scavenging rate of over 70%and some up to 100%.At this high rate,the overall cell viability in the toxicity test reached more than 80%,indicating that the synthetic derivative had a little cytotoxicity.The results show that the introduction of carboxymethyl group to chitosan increased the water-solubility of chitosan,and the combination of sulfonate ions with diff erent chain lengths further enhanced the antioxidant activity of chitosan.Therefore,the sulfonium-containing carboxymethyl chitosan derivatives had excellent bioactivity with good application prospects in food,biomedicine,and medical fi elds.
基金supported by the National High Technology Research and Development Program of China (863 Program 2006AA090401)
文摘Sulfate chitosan derivatives have good solubility and therapeutic effect on the cell model of NAFLD. The aim of this study was to examine the therapeutic effect of sulfate chitosan derivatives on NAFLD. The male Wistar rats were orally fed high fat emulsion and received sulfate chitosan derivatives for 5 weeks to determine the pre-treatment effect of sulfate chitosan derivatives on NAFLD. To evaluate the therapeutic effect of sulfate chitosan derivatives on NAFLD, the rats were orally fed with high concentration emulsion for 5 weeks, followed by sulfate chitosan derivatives for 3 weeks. Histological analysis and biomedical assays showed that sulfate chitosan derivatives can dramatically prevent the development of hepatic steatosis in hepatocyte cells. In animal studies, pre-treatment and treatment with sulfate chitosan derivatives significantly protected against hepatic steatohepatitis induced by high fat diet according to histological analysis. Furthermore, increased TC, ALT, MDA, and LEP in NAFLD were significantly ameliorated by pre-treatment and treatment with sulfate chitosan derivatives. Furthermore, increased TG, AST, and TNF-α in NAFLD were significantly ameliorated by treatment with sulfate chitosan derivatives. Sulfate chitosan derivatives have good pre-treatment and therapeutic effect on NAFLD.
基金Supported by the National Key Project for Research and Development(2016YFC0400503)the National Natural Science Foundation of China(51478314,51678408,51508385)the Science and Technology Plans of Tianjin(17PTSYJC00050,17ZYPTJC00060)
文摘Novel composite magnetic microspheres containing chitosan and quaternary ammonium chitosan derivative(CHMMs) were prepared by inverse suspension method,and used for the methyl orange(MO) removal from aqueous solutions.The CHMMs were characterized by a scanning electron microscope,a transmission electron microscope,and Fourier transform infrared spectroscopy,respectively.Compared with the chitosan beads,the incorporation of quaternary ammonium chitosan derivative significantly reduced the particle size.The MO adsorption by CHMMs was investigated by batch adsorption experiments.The adsorption kinetics was conformed to the pseudo second-order kinetics equation.The adsorption isotherm followed the Langmuir model better than the Freundlich model and the calculated maximum MO adsorption capacity was 266.6 mg·g^-1 at 293 K.Thermodynamic studies indicated that the MO adsorption was endothermic in nature with the enthalpy change(△H°) of 99.44 kJ·mol^-1.The CHMMs had a stable performance for MO adsorption in the pH range of 4-10,but high ionic strength deteriorated the MO removal due to the shielding of the ion exchange interaction.A 1 mol·L^-1 NaCl solution could be used to regenerate the exhausted CHMMs.The proposed CHMMs can be used as an effective adsorbent for dye removal or recovery from the dye wastewater.
基金supported by the National Natural Science Foundation of China(Nos.20975082and20775059)theMinistry of Education of the People's Republic of China(No.NCET-08-0464)+2 种基金the State Forestry Administration of the People's Republic of China(No.200904004)the Scientific Research Foundation for the Returned Overseas Chinese Scholars of the Ministry of EducationNorthwest Agricultural & Forestry University
文摘A new chitosan derivative is prepared using chitosan.Ethyl chlorocarbonate was first introduced to the hydroxyl group of phthaloylchitosan through a nucleophilic reaction.Hydrazine was then added to recover the amino groups of chitosan and promote cross-linking.The structure of this new chitosan derivative was characterized by Fourier transform infrared(FT-IR)and proton nuclear magnetic resonance(1H NMR)spectroscopy,and its physical properties were determined by X-ray diffraction(XRD),differential scanning calorimetry(DSC),and thermogravimetric analysis(TGA).The thermal and chemical stabilities of the new derivative were improved compared with those of native chitosan.Assay of Escherichia coli adhesion on a film based on this chitosan derivative showed good adsorption and biofilm formation.
文摘The reaction of 1-methylisoquinoline 1 with hy-drazonoyl halides 2 in ethanol in the presence of chitosan under microwave irradiation affords triazoloisoquinoline 4. Product 4 reacts with dimethylformamide-dimethylacetal to give ena- minones 7 which react with hydrazonoyl halides to give pyrazolyl triazoloisoquinoline 13. Also, 1-methylisoquinoline 1 reacts with arylisothio-cyanate to give thioanilide 15 which reacts with hydrazonoyl halides to give the corresponding thiadiazolyl isoquinoline derivatives 20, 24.
文摘An amphiphilic N-octyl-O-methoxy poly (ethylene glycol) chitosan was successfully prepared by grafting successively octyl groups onto amino groups at chitosan’s C-2 position as hydrophobic moieties and methoxy polyethylene glycol (MPEG) groups onto hydroxyl groups at C-6, C-3 as hy-drophilic ones. A certain amount of -NH2 was retained in the structure of chitosan derivatives through protection by phthalic anhydride. The chemical structures and degree of N-and O-substitution of chitosan derivatives were characterized by FTIR, 1H NMR, GPC and elemental analysis, respectively. The amphiphilic property for convenient self-assembly and the preserved -NH2 groups for progressive chemical cross-linking make the resultant Nocyl-O-MPEG chitosan soluble in water and potentially applicable in preparing stable chitosan hollow microspheres, a demanding drug-carrier in medical and pharmaceutical sciences.
文摘背景:作为天然生物材料壳聚糖的一种衍生物,羧甲基壳聚糖具有独特的水溶性、成膜性、缓释性,在组织工程领域具有广阔的应用前景。目的:综述羧甲基壳聚糖相较于壳聚糖的优势以及在口腔组织再生方面的应用。方法:利用计算机检索PubMed、中国知网数据库相关文献,中文检索词“羧甲基壳聚糖AND组织工程,羧甲基壳聚糖AND口腔医学”,英文检索词“carboxymethyl chitosan AND tissue engineering,carboxymethyl chitosan AND(dentistry OR stomatology)”,检索时限为2006年1月至2021年10月,通过阅读和分析文献进行初步筛选,以排除重复文献和低相关性文献,最终纳入文献51篇进行结果分析。结果与结论:羧甲基壳聚糖作为一种具有良好生物相容性、可降解的无毒材料,在骨组织再生、牙体组织再生、牙周组织再生方面已取得理想的进展。羧甲基壳聚糖相比壳聚糖具有更好的水溶性、成膜性和离子结合性,这极大扩展了其在口腔组织工程的应用。羧甲基壳聚糖单独使用可发挥抗菌效果,促细胞增殖、分化,或是作为支架材料、水凝胶、改性材料与生物活性成分和生长因子联合使用均达到了预期的实验效果。