The procedure for preparing a new type of uniform and porous chitosan gel from citric acid medium is described. Its swelling behavior in different media was compared with those of the gels prepared by other methods. T...The procedure for preparing a new type of uniform and porous chitosan gel from citric acid medium is described. Its swelling behavior in different media was compared with those of the gels prepared by other methods. The ultrastructure of the xerogel prepared from citric acid was characterized using electron microscopy (SEM).展开更多
The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid（HA） and Chitosan（CS） were successfully admixed with Ca^2＋/alginate（SA） gel system to produce SA/HA/CS...The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid（HA） and Chitosan（CS） were successfully admixed with Ca^2＋/alginate（SA） gel system to produce SA/HA/CS gel beads by dual crosslinking： the ionic gelation and the polyelectrolyte complexation. The preparation procedure was that the weight ratio of SA（2%, m/v） to HA（2%, m/v） was kept at 2：1, then the mixture was dripped into the Ca^2＋ solution for ion-crosslinking, and finally polyelectrolyte crosslinked with 2% low molecular weight CS（LMW-CS） for 1.5 hours. The optimal formulation was achieved by adjusting the concentration and the weight ratio of SA, HA and LMW-CS. Due to the incorporation of HA and LMWCS, the swelling ratio of the beads at pH 7.4 was increased up to 120, and the time for the maximum swelling degree was prolonged to 7.5 h. The swelling behavior was obviously improved compared to the pure SA/Ca^2＋ system. The preliminary results clearly suggest that the SA/HA/CS gel beads may be a potential candidate for biomedical delivery vehicles.展开更多
Recently, potential applications for β-chitosan (β-CS) have been examined. In the present study, calcium-induced alginate gel beads (Alg-Ca) containing weak acid salts of β-CS were prepared and examined with regard...Recently, potential applications for β-chitosan (β-CS) have been examined. In the present study, calcium-induced alginate gel beads (Alg-Ca) containing weak acid salts of β-CS were prepared and examined with regard to their ability to adsorb bile acids in vitro. More than 70% of taurocholate dissolved in solution was taken up by Alg-Ca containing 100 mg β-CS, sim. ilar to the degree of uptake observed with Alg-Ca containing α-CS salt. The adsorption of bile acid was affected by the absolute amount of β-CS and/or the acid concentration of the preparation. A secondary bile acid, taurodeoxycholate, was also adsorbed by Alg-Ca containing weak acid salts of β-CS. Therefore, β-CS might be used to adsorb bile acids within the gastrointestinal tract in the same manner as an anion-exchange resin, and thus serve as a complementary means by which to prevent hyperlipidemia.展开更多
Sucrose ester( SE) was fixed on surface of poly( ethylene terephthalate)( PET) fibers to improve surface activity. Chitosan( CS) was used to graft onto pretreated PET fibers by sol-gel method. The transformations of s...Sucrose ester( SE) was fixed on surface of poly( ethylene terephthalate)( PET) fibers to improve surface activity. Chitosan( CS) was used to graft onto pretreated PET fibers by sol-gel method. The transformations of surface chemical structure,microcosmic morphology and thermodynamic property were investigated by Fourier transform infrared spectroscopy( FTIR),X-ray photoelectron spectroscopy( XPS), scanning electron microscope( SEM), X-ray diffraction technique( XRD), and thermo gravimetric analysis( TGA),respectively. The wettability and antistatic property of PET fiber were significantly improved after modification by SE and CS.展开更多
This paper reports a new method to prepare chitosan membrane which could be used as a biomedical material. Addition of a fixation agent composed of alcohol, glycerol and potassium hydroxide can accelerate the sol-gel ...This paper reports a new method to prepare chitosan membrane which could be used as a biomedical material. Addition of a fixation agent composed of alcohol, glycerol and potassium hydroxide can accelerate the sol-gel transformation process and hence shorten the preparation period. The present method takes about 6 h to get a flexible membrane with fine appearance, The physical and biological properties of the membrane were also investigated and compared with the membrane prepared by conventional method.展开更多
壳聚糖-果胶凝胶珠(Chitosan-pectin gel beads,CPB)吸附去除食品中重金属具有较高的潜力,为提高其稳定性、再生利用性及吸附能力,本文采用明胶(Gel)和羧甲基纤维素钠(CMC)对CPB进行改性,利用扫描电镜(SEM)、比表面积与孔隙度分析(BET)...壳聚糖-果胶凝胶珠(Chitosan-pectin gel beads,CPB)吸附去除食品中重金属具有较高的潜力,为提高其稳定性、再生利用性及吸附能力,本文采用明胶(Gel)和羧甲基纤维素钠(CMC)对CPB进行改性,利用扫描电镜(SEM)、比表面积与孔隙度分析(BET)、傅里叶变换红外光谱(FTIR)、热重分析(TG)、Zeta电位仪、X射线光电子能谱(XPS)及等技术表征其结构特性,优化吸附解析条件,并评估其对藻蓝蛋白中Pb(Ⅱ)的实际去除效果。结果显示,与CPB和Gel-CPB相比,CMC改性的CPB(CMC-CPB)热稳定性高、表面粗糙多孔、比表面积大(20.28±1.35 m^(2)/g)及Zeta电位低,对金属离子吸附能力强,且解析再生利用率高。FTIR图谱分析显示改性前后CPB官能团结构未发生明显变化,其主要结构官能团为羧基、羟基和氨基。TG分析表明改性前后的CMC-CPB的热稳定性显著高于CPB和Gel-CPB(P<0.05)。XPS光谱分析表明三种吸附剂成功吸附了Pb(Ⅱ),其中CMC-CPB对Pb(Ⅱ)的吸收峰最强。三种吸附剂(CPB、Gel-CPB和CMC-CPB)去除Pb(Ⅱ)的最佳pH和温度分别为6.0和60℃,对Pb(Ⅱ)的吸附过程均符合Langmuir吸附等温模型(R^(2)=0.9543~0.9811)和准二级动力学模型(R^(2)=0.9963~0.9991),该吸附属于单分子层化学吸附,即-COO、-OH、-CO-NH与Pb(Ⅱ)之间的络合作用。根据Langmuir模型曲线评估,CMC-CPB对Pb(Ⅱ)的最大吸附容量q_(max)为69.37 mg/g,显著高于Gel-CPB和CPB(P<0.05)。综合在藻蓝蛋白中的应用效果,CMC-CPB低成本高效安全地去除藻类和藻蓝蛋白食品中Pb(Ⅱ)具有更广阔的前景。展开更多
基金Sponsored by a Girant-in-Aid from the Ministry of Education of China.
文摘The procedure for preparing a new type of uniform and porous chitosan gel from citric acid medium is described. Its swelling behavior in different media was compared with those of the gels prepared by other methods. The ultrastructure of the xerogel prepared from citric acid was characterized using electron microscopy (SEM).
基金Funded by the National Natural Science Foundation of China(No.81401510)
文摘The aim of this study was to fabricate composite gel beads based on natural polysaccharides. Hyaluronic acid（HA） and Chitosan（CS） were successfully admixed with Ca^2＋/alginate（SA） gel system to produce SA/HA/CS gel beads by dual crosslinking： the ionic gelation and the polyelectrolyte complexation. The preparation procedure was that the weight ratio of SA（2%, m/v） to HA（2%, m/v） was kept at 2：1, then the mixture was dripped into the Ca^2＋ solution for ion-crosslinking, and finally polyelectrolyte crosslinked with 2% low molecular weight CS（LMW-CS） for 1.5 hours. The optimal formulation was achieved by adjusting the concentration and the weight ratio of SA, HA and LMW-CS. Due to the incorporation of HA and LMWCS, the swelling ratio of the beads at pH 7.4 was increased up to 120, and the time for the maximum swelling degree was prolonged to 7.5 h. The swelling behavior was obviously improved compared to the pure SA/Ca^2＋ system. The preliminary results clearly suggest that the SA/HA/CS gel beads may be a potential candidate for biomedical delivery vehicles.
文摘Recently, potential applications for β-chitosan (β-CS) have been examined. In the present study, calcium-induced alginate gel beads (Alg-Ca) containing weak acid salts of β-CS were prepared and examined with regard to their ability to adsorb bile acids in vitro. More than 70% of taurocholate dissolved in solution was taken up by Alg-Ca containing 100 mg β-CS, sim. ilar to the degree of uptake observed with Alg-Ca containing α-CS salt. The adsorption of bile acid was affected by the absolute amount of β-CS and/or the acid concentration of the preparation. A secondary bile acid, taurodeoxycholate, was also adsorbed by Alg-Ca containing weak acid salts of β-CS. Therefore, β-CS might be used to adsorb bile acids within the gastrointestinal tract in the same manner as an anion-exchange resin, and thus serve as a complementary means by which to prevent hyperlipidemia.
文摘Sucrose ester( SE) was fixed on surface of poly( ethylene terephthalate)( PET) fibers to improve surface activity. Chitosan( CS) was used to graft onto pretreated PET fibers by sol-gel method. The transformations of surface chemical structure,microcosmic morphology and thermodynamic property were investigated by Fourier transform infrared spectroscopy( FTIR),X-ray photoelectron spectroscopy( XPS), scanning electron microscope( SEM), X-ray diffraction technique( XRD), and thermo gravimetric analysis( TGA),respectively. The wettability and antistatic property of PET fiber were significantly improved after modification by SE and CS.
基金Project supported by the Natural Science Foundation of Zhejiang Province (No. 500041)
文摘This paper reports a new method to prepare chitosan membrane which could be used as a biomedical material. Addition of a fixation agent composed of alcohol, glycerol and potassium hydroxide can accelerate the sol-gel transformation process and hence shorten the preparation period. The present method takes about 6 h to get a flexible membrane with fine appearance, The physical and biological properties of the membrane were also investigated and compared with the membrane prepared by conventional method.
文摘壳聚糖-果胶凝胶珠(Chitosan-pectin gel beads,CPB)吸附去除食品中重金属具有较高的潜力,为提高其稳定性、再生利用性及吸附能力,本文采用明胶(Gel)和羧甲基纤维素钠(CMC)对CPB进行改性,利用扫描电镜(SEM)、比表面积与孔隙度分析(BET)、傅里叶变换红外光谱(FTIR)、热重分析(TG)、Zeta电位仪、X射线光电子能谱(XPS)及等技术表征其结构特性,优化吸附解析条件,并评估其对藻蓝蛋白中Pb(Ⅱ)的实际去除效果。结果显示,与CPB和Gel-CPB相比,CMC改性的CPB(CMC-CPB)热稳定性高、表面粗糙多孔、比表面积大(20.28±1.35 m^(2)/g)及Zeta电位低,对金属离子吸附能力强,且解析再生利用率高。FTIR图谱分析显示改性前后CPB官能团结构未发生明显变化,其主要结构官能团为羧基、羟基和氨基。TG分析表明改性前后的CMC-CPB的热稳定性显著高于CPB和Gel-CPB(P<0.05)。XPS光谱分析表明三种吸附剂成功吸附了Pb(Ⅱ),其中CMC-CPB对Pb(Ⅱ)的吸收峰最强。三种吸附剂(CPB、Gel-CPB和CMC-CPB)去除Pb(Ⅱ)的最佳pH和温度分别为6.0和60℃,对Pb(Ⅱ)的吸附过程均符合Langmuir吸附等温模型(R^(2)=0.9543~0.9811)和准二级动力学模型(R^(2)=0.9963~0.9991),该吸附属于单分子层化学吸附,即-COO、-OH、-CO-NH与Pb(Ⅱ)之间的络合作用。根据Langmuir模型曲线评估,CMC-CPB对Pb(Ⅱ)的最大吸附容量q_(max)为69.37 mg/g,显著高于Gel-CPB和CPB(P<0.05)。综合在藻蓝蛋白中的应用效果,CMC-CPB低成本高效安全地去除藻类和藻蓝蛋白食品中Pb(Ⅱ)具有更广阔的前景。
