沉淀聚合法制备壳聚糖磁性微球

要用共沉淀法制备Fe3O4磁性纳米粒子,并对其用油酸进行表面改性,继而采用沉淀聚合法制备壳聚糖磁性微球。考察了沉淀剂浓度、乳化剂种类、Fe3O4的改性等条件对制备微球的影响。应用扫描电镜、红外谱图、接触角仪、粒径分析仪及磁铁吸附对壳聚糖磁性微球的形态与特性进行了表征。研究结果表明,在适宜的沉淀剂浓度、复合乳化剂、Fe3O4经油酸改性等条件下,可以制得平均粒径为150nm、单分散性好且磁性明显的壳聚糖磁性微球。     

生物模板法制备磁性中空微球的方法和应用

磁性中空微球在功能性吸附、酶固定化载体、物质的分离纯化、活性物质和药物的封装与控释、靶向给药、污染防治、食品和材料学等领域有突出的应用价值。文章综述了利用生物模板法制备磁性中空微球的制备原理和最新研究成果,并主要分析了软模板法和自模板法两种制备工艺。软模板法工艺主要通过吸附-高温炭化法除去生物模板材料获得固定外形的磁性中空微球。自模板法制备磁性中空微球可依据生物材料自身成分经水热碳化反应或在惰性气体氛围保护下的高温炭化反应生成具有特殊官能团结构的中空碳微球,并将磁性物质溶入或吸附到中空微球中,具体分为水热碳化法和浸渍-高温炭化法;也可将制备好的磁性物质吸附于经过特殊处理过的生物模板材料表面,如吸附-共沉淀法和高温炭化-共沉淀法。总之,生物模板法制备磁性中空微球条件较为温和、无污染,生物模板材料对人体无毒,特别适合于食品、医药等行业的应用,具有很好的生产应用前景。     

磁性复合微球对铬离子的吸附条件研究

以磁性纳米壳聚糖微球为载体,戊二醛为交联剂,采用共价交联法,负载鞘细菌S9构建磁性鞘细菌微球。通过单因素和正交设计实验,对该复合生物微球吸附铬离子的条件进行研究,结果发现磁性复合微球对铬离子的吸附性能明显高于磁性纳米壳聚糖和游离鞘细菌,同时得到最适吸附组合为A1B1C1,即当铬离子初始浓度为40mg/m L,吸附温度30℃,吸附时间30min,磁性复合微球对铬离子的吸附作用最佳,吸附量和吸附率分别为58.16mg/g和44.52%。     

新型磁性吸附材料的合成及表征

水中重金属的脱除是污水处理中的重要内容。吸附法是一种除去水中重金属污染的简单高效的方法。磁性吸附剂具有成本低、无二次污染、吸附率高、便于分离和再生等特点,在污水处理上有着重要的应用前景。本文采用溶剂热法制备磁性Fe_3O_4纳米粒子,考察了外部条件对磁性Fe_3O_4纳米粒子生成的影响,确定了制备磁性Fe_3O_4纳米粒子的最佳条件。制备了Fe_3O_4@SiO_2复合微球,通过将壳聚糖键合到颗粒表面并接枝三乙烯四胺改性,得到氨基修饰的磁性Fe_3O_4纳米粒子。     

磁性壳聚糖微球的制备及其固定化乳糖酶的研究

采用水热法制备得到磁性Fe_3O_4纳米粒子,以壳聚糖、制备的Fe_3O_4为原料,采用乳化交联法成功制备了磁性壳聚糖微球,并通过SEM、FTIR、VSM、XRD对其进行表征。进一步以制备的磁性壳聚糖微球为载体,采用吸附法制备磁性壳聚糖微球固定化乳糖酶。以酶活力为考察指标,研究了不同固定化条件对制备固定化酶的影响,以及固定化酶的酶学性质。结果表明,乳糖酶的最佳固定化条件为:固定化时间4 h,pH为7.0,乳糖酶酶液浓度为0.6 mg/mL,固定化酶相对于游离酶的pH稳定性和温度稳定性均有一定程度的提高,固定化酶重复使用5次后,酶活仍保留65%以上。     

羧酸修饰壳聚糖磁性微球及对甲基橙的吸附

以壳聚糖原料,用共沉淀法制备了壳聚糖磁性微球(CS-MCP),用己二酸、顺丁烯二酸酐、柠檬酸分别对其修饰得到三种后修饰微球CA-MCP,CB-MCP,CD-MCP,并进行了红外光谱(IR)、粉末X-射线衍射分析(XRD)表征。测定了四种微球在不同pH条件下对甲基橙的吸附性能,结果表明在pH范围为4～10时吸附效果最佳,己二酸、顺丁烯二酸酐修饰后的壳聚糖磁性微球对甲基橙的吸附效果明显改善。     

磁性壳聚糖微球的研究进展

磁性氧化铁纳米粒子（Fe3O4,γ-Fe2O3等）因具有尺寸小、超顺磁性和低毒性等特点,已经引起了生物化工、医药工业研究领域的广泛关注。磁性壳聚糖微球具有表面非常光滑的球形结构。近年来,已经制备出了平均粒径在10～2.5×105 nm之间的磁性壳聚糖微球,并在生物医药、食品工程和污水处理等许多领域已经取得了初步的应用,特别是在污水处理和酶固定化领域。本文综述了近年来磁性氧化铁纳米粒子和磁性壳聚糖微球的制备方法、磁性壳聚糖微球的改性方法及应用的最新研究成果。     

壳聚糖磁性微球的制备及其对牛血清白蛋白的吸附性能研究

以Fe/C为磁性内核、液体石蜡为分散介质、Span-80为乳化剂、环氧氯丙烷为交联剂,采用反相悬浮包埋法制备了壳聚糖磁性微球.对微球表面的活性基团含量进行了测定.研究了用戊二醛活化、Cibacron Blue 3G-A修饰后的微球对牛血清白蛋白的吸附性能.结果表明,小粒径壳聚糖磁性微球经戊二醛活化后对牛血清白蛋白的饱和吸附量为46.3 mg·g-1,经Cibacron Blue 3G-A修饰后对牛血清白蛋白的饱和吸附量为66.2 mg·g-1.     

磁性壳聚糖微球制备及其对Pb2+的吸附性能研究

课题利用化学共沉淀法制备出Fe₃O₄粒子,在壳聚糖溶液中加入Fe₃O₄粒子进行改性,成功制备出磁性壳聚糖微球。课题以Pb²⁺作为吸附目标,探究了磁性壳聚糖微球对Pb²⁺的吸附的最优条件,并对磁性壳聚糖微球进行回收、再利用。结果表明,50 mL,50 mg/L Pb²⁺溶液投加量为150 mg、pH为6、温度35℃、时间为1 h是吸附实验的最佳条件,制备的吸附剂具有较好的吸附量和Pb²⁺去除率,且能够实现回收再生,具有环境友好性。     

磁性NiO的制备及其选择性吸附性能

采用简单溶液法合成了分等级花状磁性氧化镍(NiO)微球,研究了制备的花状磁性NiO微球对水中染料刚果红的吸附效果,并探讨了吸附机理。结果表明,花状磁性NiO微球对刚果红的最大吸附量达155.9 mg/g,吸附机理可归因于带正电荷的吸附剂表面与阴离子染料刚果红之间的静电相互作用。磁性NiO微球能通过磁铁快速从溶液中分离,且对阴离子染料具有良好的选择吸附性能。     

磁性壳聚糖微球的制备及其对2，4-二氯苯酚的吸附

采用反相悬浮聚合法合成了磁性壳聚糖微球,平均粒径不超过5μm。将其用于2,4-二氯苯酚的吸附研究。考察了吸附时间、吸附温度、DCP浓度以及磁性壳聚糖用量等因素对氯酚吸附的影响。结果表明,温度对吸附影响不大,最佳吸附时间为2h时,吸附剂磁性壳聚糖微球用量为1g。对DCP的吸附率在80％以上。在最佳条件下的吸附容量为1．70mg／g。     

Magnetic chitosan microspheres: preparation and characterization

In this study, magnetic chitosan microspheres were prepared in a well shaped spherical form with a size range of 100 to 250 μm (size distribution ±15 to ±40 μm, respectively) by the suspension cross-linking technique for use in the application of magnetic carrier technology. The magnetic material (i.e. Fe₃O₄) used in the preparation of the magnetic chitosan microspheres was prepared by precipitation from FeSO₄ and Fe₂(SO₄)₃ solutions in basic medium and then ground to the desired size (i.e. 1–5 μm). The morphological and magnetic properties of the microspheres were characterized by different techniques (i.e. SEM, optical microscopy, magnetometry). The results demonstrated that the stirring rate of the suspension medium and the Fe₃O₄/chitosan ratio are the most effective parameters for the size/size distribution and the magnetic quality of the microspheres, while the chitosan molecular weight (MW) has no significant effect on these properties for the given MW range (i.e. 150 to 650 kDa). The best magnetic quality of the magnetic chitosan microspheres is around 9.1 emu/g microsphere at 10 kG magnetic field intensity.     

Synthesis and characterization of composite magnetic microspheres of artemisia seed gum and chitosan

In this study, composite magnetic microspheres of artemisia seed gum and chitosan were prepared in a well‐shaped spherical form with a size range of 230–460 μm by the suspension crosslinking technique for use in the application of magnetic carrier technology. The magnetic material used in the preparation of the composite microspheres was prepared by precipitation from FeCl₃ and FeSO₄ solution in basic medium. The morphological, magnetic properties, and the functional groups of the microspheres were characterized by different techniques (i.e., SEM, magnetometry, and FTIR). The results demonstrated that the stirring rate of the suspension and the Fe₃O₄/chitosan ratio are the most effective parameters for the average of the size distributions and the magnetic quality of the microspheres, while the amount of artemisia seed gum and Tween‐80 have no significant effect on these properties. The best magnetic quality of the composite magnetic microspheres is around 4.08 emu/g microspheres at 10 KG magnetic field intensity. The thermal stability of the composite magnetic microspheres was measured by using DSC methods. © 2006 Wiley Periodicals, Inc. J Appl Polym Sci 103: 3045–3049, 2007     

Cu(Ⅱ)螯合壳聚糖磁性微球的制备、表征及性能研究

以(NH4)2Fe(SO4)2.6H2O、NH4Fe(SO4)2.12H2O和壳聚糖为原料,经羟丙基化、Cu(Ⅱ)螯合,采用一步包埋法制备了一种Cu(Ⅱ)螯合壳聚糖磁性微球。通过正交实验法确定了磁性微球的最佳制备条件,即搅拌速度1 200 r/min,壳聚糖用量3.0 g,环氧氯丙烷用量1.0 mL,CuCl2.2H2O为0.010 mol。并用IR、TG、XRD和SEM对其结构及形貌进行了表征,结果表明,Fe3O4磁性粒子已包埋了一层Cu(Ⅱ)螯合壳聚糖,呈较规则的球形,平均粒径为240 nm,且具有顺磁性。     

乙二胺改性磁性壳聚糖微球制备及其对Cu~(2+)和Pb~(2+)吸附

以(NH4)2Fe(SO4)2.6H2O、NH4Fe(SO4)2.12H2O和壳聚糖为原料,经羟丙基化、氨基化,采用一步包埋法制备了一种新型的多氨基化磁性壳聚糖微球。并通过正交实验确定了改性磁性微球的最佳制备条件,即搅拌速度1200 r/min,壳聚糖用量3.0g,环氧氯丙烷用量5.0mL,乙二胺用量2.5mL。用荧光显微镜对其结构及形貌进行了观察。结果表明,Fe3O4磁性粒子已包埋了一层氨基化壳聚糖。改性磁性微球氨基含量为3.60mmol/g;呈较规则的球形,平均粒径为211.6nm。讨论在最佳条件下制备的壳聚糖微球对污水中Cu2+和Pb2+的吸附能力。     

磁性壳聚糖/β-环糊精复合微球的制备及其吸附性能

以反相悬浮交联法制备磁性壳聚糖/β-环糊精复合微球。用光学显微镜、红外光谱仪、振动样品磁强计(VSM)对微球进行了表征,并研究其对模型蛋白(木瓜蛋白酶)的吸附行为。结果表明,微球为完整的球形,具有良好的磁响应性。模型蛋白在微球上的吸附关系既可用Langmuir方程描述,又可用计量置换吸附Freundlich方程描述,且更符合Freundlich方程描述;聚丙烯酰胺凝胶电泳(SDS-PAGE)结果表明,吸附的模型蛋白能从磁性粒子表面完整地脱附下来。     

Evaluating chitosan/β‐tricalcium phosphate/poly(methyl methacrylate) cement composites as bone‐repairing materials

This study related to the preparation of chitosan microspheres by means of reacting chitosan with β‐tricalcium phosphate (β‐TCP) and glutaraldehyde by crosslinking reaction in the oil phase, followed by de‐oil and purification processes to get the product. Three cement composites, Pure P, C1P1, and C2P1, were prepared by the polymerization of poly(methyl methacrylate) (PMMA) bone cement in the presence of 0, 50, and 66.7% chitosan/β‐TCP microspheres, respectively. The result revealed the chitosan/β‐TCP microspheres obtained was in the size range of 50–150 μm. The presence of chitosan/β‐TCP microspheres in the prepared composites decreased the ultimate tensile strength, whereas the modulus remained the same as compared with the commercial PMMA bone cement. Addition of chitosan/β‐TCP microspheres into commercial PMMA cement significantly improved the handling property of the cement paste—that is, the increased setting time and less stickiness behavior of this paste was beneficial, in manipulation, to the operation and easier fittings to the shape and gap of the bony defect and interface. The decreased curing temperature was also less harmful to the surrounding tissues. From scanning electron micrograph observations, chitosan/β‐TCP microspheres can completely mix with bone cement powder and the prepared composites could provide scaffold for osteoblast cells growth and thus improve defects of commercial PMMA bone cement. © 2003 Wiley Periodicals, Inc. J Appl Polym Sci 89: 3897–3904, 2003     

Characterization and application of high magnetic property chitosan particles

High magnetic property chitosan particles were prepared from chitosan coated on magnetic powder, glutaraldehyde modified, and then epichlorohydrin crosslinked. The magnetic properties, the surface, and the morphology of the magnetic particles were characterized. An optimum condition of immobilization of aprotinin on magnetic particles was obtained, then these particles were used for affinity purification of trypsin, and the condition of affinity purification was discussed. The proposed method was successfully applied to the purification of trypsin. © 2001 John Wiley & Sons, Inc. J Appl Polym Sci 81: 1175–1181, 2001     

超顺磁性聚醋酸乙烯酯微球亲和分离纳豆激酶

采用改进悬浮聚合法制备了磁性聚醋酸乙烯酯微球,经水解、氨基化修饰,以戊二醛作间隔臂偶联配基对氨基苯甲脒,制得磁性PVA亲和微球,用于纳豆激酶粗酶液的分离纯化,对所制微球进行了表征,研究了纳豆激酶的吸附平衡、吸附和解吸动力学、酶的纯度和酶活回收. 结果表明,磁性微球具有较高的比饱和磁化强度(32.4 emu/g),40 min即可达到纳豆激酶的吸附平衡,15 min内完成酶的解吸,酶活回收率接近75%,纯化因子为10.3,酶的分子量为28 kDa,电泳分析为一条带.