仿生壳聚糖基纳米纤维的自组装构建

通过天然阳离子型高分子壳聚糖与三聚磷酸钠的静电自组装,制备模仿细胞外基质纳米结构的仿生壳聚糖基纳米纤维。研究了介质、壳聚糖浓度、反应物比例、添加胶原等因素对自组装复合产物的影响;并采用透射电镜、X射线衍射和红外光谱等技术表征了纳米纤维的结构。结果表明,介质对壳聚糖基纳米复合物的结构和形态的影响很大;以己二酸溶液为介质,在温和条件下,可获得结构可控的壳聚糖基纳米纤维,有望用于构建模仿天然细胞外基质的组织工程支架。     

仿生壳聚糖基纳米纤维的自组装构建EI北大核心

通过天然阳离子型高分子壳聚糖与三聚磷酸钠的静电自组装,制备模仿细胞外基质纳米结构的仿生壳聚糖基纳米纤维。研究了介质、壳聚糖浓度、反应物比例、添加胶原等因素对自组装复合产物的影响;并采用透射电镜、X射线衍射和红外光谱等技术表征了纳米纤维的结构。结果表明,介质对壳聚糖基纳米复合物的结构和形态的影响很大;以己二酸溶液为介质,在温和条件下,可获得结构可控的壳聚糖基纳米纤维,有望用于构建模仿天然细胞外基质的组织工程支架。     

PEC载药微胶囊的自组装及缓释性能

为探讨多糖类生物质材料的高效利用,文中以纤维素硫酸钠-氯化壳聚糖-三聚磷酸钠(NaCS-CHC-STPP)微胶囊为核心/模板,以1%NaCS和0.5%CHC作为自组装的聚电解质溶液,采用层层自组装法制备了具有4层膜层结构的PEC_4微胶囊,探究了自组装膜层结构对微胶囊的缓释性能影响。通过数码单反相机、扫描电子显微镜、Zeta电位分析等对PEC微胶囊的膜层结构进行了表征,并在模拟结肠液中对载药微胶囊的释放性能进行了测定与分析。结果表明,与模板相比(n=0),经层层自组装后得到的微胶囊形貌圆润,内部结构更加致密(1≤n≤3)。Zeta电位分析表明,随NaCS与CHC的交替组装,电位呈现规律性变化。傅里叶变换红外分析表明CHC与NaCS发生了化学反应。释放研究表明,随着自组装PEC膜层结构的增加(1≤n≤2),载药微胶囊的缓释给药效果得到明显提升,释放过程中微胶囊逐渐变褶皱、粗糙,伴有微孔结构。该研究结果可以为生物质材料构建缓释型药物递送体系提供理论参考。     

壳聚糖基纳米胶囊的制备及应用研究新进展

壳聚糖是自然界产量最大的氨基多糖,具有较好的生物降解性、生物相容性、成膜性及良好的抗菌性.主要阐述了近年来制备壳聚糖基纳米胶囊的一些方法,如离子交联法、界面聚合法及层层自组装法等,并着重综述了近年来壳聚糖基纳米胶囊在医药、食品及纺织领域的应用研究进展.最后,根据现阶段的研究状况对壳聚糖基纳米胶囊的研究前景做了展望.     

金纳米粒子的制备及自组装

金纳米粒子以它独特的光学、电学和催化性质以及在纳米级电子线路中的应用潜力,受到人们越来越多的关注.本文主要评述了金纳米粒子的合成方法和自组装技术,即对各种制备方法和自组装的特点、纳米粒子的生长机理和自组装机理进行了介绍.展望了金纳米材料未来的研究方向和发展趋势.     

大分子自组装体系及自组装功能膜结构的研究

本文主要介绍了３种大分子自组装体系，含硫化合物的在重金属表面的自组装功能膜、聚合物在溶液状态下的自组装体系和聚合物基材上的自组装功能膜。文中还介绍了表征自组分析方法，着重介绍了用于自组装功能膜表面、界面结构分析的两种，红外光谱法和原子力显微镜。     

静电自组装功能性纳米复合膜的研究进展

通过静电相互作用可自组装形成功能性纳米复合膜.近年来,这一技术发展十分迅速,并且得到了广泛的应用.综述了静电自组装成膜的机理、制备、表征的最新研究进展.     

纳米颗粒的模板自组装

纳米颗粒具有优异的物理化学性质,是各种超结构材料最为重要的构造基元。作为一种"自下而上"的制备方法,模板自组装技术可以控制纳米颗粒在自组装超结构材料中的位置和排列顺序,尤其适用于制备规整、多组分、结构复杂的自组装体系。介绍了纳米颗粒自组装方法中常用的模板,以及利用这些模板实现纳米颗粒自组装的一般过程。强调了纳米颗粒与模板之间的物理、化学作用,从本质上阐明模板自组装方法,为制备功能性复杂纳米颗粒自组装材料提供了有益的借鉴。     

纳米壳自组装结构呈独特光学性能

据美国物理学家组织网报道,美国科学家找到了一种方法,使7个＂纳米壳＂（nanoshell）自组装成一个具有独特光学性能的＂七聚物＂。科学家表示,就像儿童使用积木搭建出复杂的建筑物或者车辆一样,这种自组装纳米粒子的方法可以用来制造能够捕捉、存储和弯曲光线的复杂物体,比如化学传感器、纳米激光器等。相关研究论文刊登在5月27日的《科学》杂志上。     

自组装白蛋白共负载光敏剂及基因纳米递送系统的构建及初步评价

通过小分子十二烷基硫酸钠(SDS)调节牛血清白蛋白(BSA)疏水区域暴露,使白蛋白分子在不借助额外催化剂和交联剂的相对温和条件下自组装,合成了一种可共载光敏剂二氢卟吩e6(Ce6)及基因(CpG寡脱氧核苷酸)的白蛋白纳米载体。在其成功负载光敏剂Ce6后,用聚醚酰亚胺(PEI)对BSA纳米颗粒(BSA NP)表面进行了修饰,并通过调节合适的修饰比例得到高效负载基因的纳米体系。随后对纳米颗粒体系的形貌、尺寸分布、表面电荷、稳定性以及基因负载能力、产生活性氧能力进行了初步评估。结果表明合成得到的PEI修饰的白蛋白共负载Ce6及CpG(BSA-Ce6-PEI-CpG)的纳米颗粒尺寸分布均匀,微观形貌呈现光滑规整的圆球形,对CpG基因有较好的负载能力,并在光照下高效产生活性氧,且纳米体系能够在表面活性剂处理后依然保持结构稳定,可作为良好的光敏剂和基因递送载体。     

壳聚糖微球的制备及其在药物载体中的应用

壳聚糖因其具有良好的生物学特性而成为药物载体研究的热点。药物经壳聚糖负载后,不仅能够达到缓释控释的目的,还能够改变药物的给药方式,降低药物不良反应,提高药物生物利用度。本文就壳聚糖微球的制备及其在药物载体中的应用作一综述。     

海藻酸钠作为药物载体材料的研究进展

综述海藻酸钠作为药物载体材料的研究进展;依据国内外的文献报道来阐述海藻酸盐凝胶材料、海藻酸钠共混材料、海藻酸钠化学改性材料作为药物载体材料的研究进展;海藻酸钠作为药物载体材料有很广阔的应用前景.     

SiO2气凝胶/壳聚糖复合药物载体材料的制备和表征

采用常压干燥法制备了SiO2气凝胶,所得气凝胶为介孔结构,比表面积618.8m2/g,孔径分布5～20nm.以SiO2气凝胶为原料,通过静电吸附法制备了SiO2气凝胶/壳聚糖复合药物载体材料,采用扫描电镜(SEM)、红外光谱(FTIR)等对复合材料的结构形貌进行了分析,研究了复合材料对硫酸庆大霉素药物的担载和释放性能.结果表明,所得SiO2气凝胶/壳聚糖复合材料为多孔网络结构,其中,由450℃处理的SiO2气凝胶制得的气凝胶/壳聚糖复合材料对硫酸庆大霉素具有较好的药物担载和缓释性能.     

Glucose-conjugated chitosan nanoparticles for targeted drug delivery and their specific interaction with tumor cells

A novel targeted drug delivery system, glucose-conjugated chitosan nanoparticles （GCNPs）, was developed for specific recognition and interaction with glucose transporters （Gluts） over-expressed by tumor cells. GC was synthesized by using succinic acid as a linker between glucosamine and chitosan （CS）, and successful synthesis was confirmed by NMR and elemental analysis. GCNPs were prepared by ionic crosslinking method, and characterized in terms of morphology, size, and zeta potential. The optimally prepared nanoparticles showed spherical shapes with an average particle size of （187.9 ± 3.8） nm and a zeta potential of （-15.43 ± 0.31） mV. The GCNPs showed negligible cytotoxicity to mouse embryo fibroblast and 4T1 cells. Doxorubicin （DOX） could be efficiently entrapped into GCNPs, with a loading capacity and encapsulation efficiency of 20.11% and 64.81%, respectively. DOX-Ioaded nanoparticles exhibited sustained-release behavior in phosphate buffered saline （pH 7.4）. In vitro cellular uptake studies showed that the GCNPs had better endocytosis ability than CSNPs, and the antitumor activity of DOX/GCNPs was 4-5 times effectiveness in 4T1 cell killing than that of DOX/CSNPs. All the results demonstrate that nanoparticles decorated with glucose have specific interactions with cancer cells via the recognition between glucose and Gluts. Therefore, Gluts-targeted GCNPs may be promising delivery agents in cancer therapies.     

Photoresponsive coumarin-stabilized polymeric nanoparticles as a detectable drug carrier

The ability to create aqueous suspended stable nanoparticles of the hydrophobic homopolymer poly(?‐caprolactone) end‐functionalized with coumarin moieties (CPCL) is demonstrated. Nanoparticles of CPCL are prepared in a continuous manner using nanoprecipitation. The resulting nanoparticles are spherical in morphology, about 40 nm in diameter, and possess a narrow size distribution and excellent stability over 4 months by repulsive surface charge. Nanoparticle size can be easily controlled by manipulating the concentration of CPCL in the solution. The interparticle assembly between the nanoparticles can be reversibly adjusted with photoirradiation due to photoinduced [2 + 2] cyclodimerization and cleavage between the coumarin molecules. In addition, the CPCL nanoparticles show significant cellular uptake without cytotoxicity, and the intrinsic fluorescence of the coumarin functional group permits the direct detection of cellular internalization.     

Sublingual spray drug delivery of ketorolac-loaded chitosan nanoparticles

Introduction: The aim of this study was to investigate ketorolac (KT) systemic absolute bioavailability after sublingual (SL) administration in vivo to conscious rabbits. Furthermore, the study investigated the potential use of chitosan nanoparticles as a delivery system to enhance the systemic bioavailability of KT following SL administration.

Methods: Ketorolac-loaded chitosan nanoparticles were prepared through ionotropic gelation of chitosan with tripolyphosphate anions. The KT-nanoparticles were administered SL as a spray to rabbits and KT plasma concentration at predetermined time points was compared to SL spray administration of KT in solution. The concentrations of KT in plasma were analyzed by ultra-performance liquid chromatography mass spectroscopy (UPLC/MS).

Results: KT-loaded chitosan nanoparticles significantly (p?Conclusions: The results of the present study suggest that SL absorption of KT illustrated flip-flop kinetics with prolonged persistence in the body compared to intravenous administration. Formulation of KT as chitosan nanoparticles has increased its systemic bioavailability after SL spray administration. The new delivery system could be an attractive approach for the delivery of KT.     

新型药物载体材料——端羟基聚(丙交酯-co-对二氧环己酮)的合成与表征

聚乳酸(PLA)作为药物载体材料存在因疏水性强而导致的药物释放速率难控以及在循环系统中停留时间短等问题.研究表明,在PLA中引入乙醇酸(GA)可提高材料降解速率,引入聚乙二醇(PEG)则可延长共聚物在循环系统中的停留时间.研究以丙交酯(LA)和对二氧环己酮(PDO)为主要原料,在辛酸亚锡-乙二醇共引发体系的存在下,通过熔融开环聚合制备出了端羟基聚(丙交酯-co-对二氧环己酮)(HO-P(LA-co-PDO)-OH).这种同时具有PLA、GA和EG结构单元的大分子二醇可望成为一种降解速率可控、在循环系统中停留时间可调的新型药物载体材料.采用DSC、~1H NMR、~(13)C NMR和GPC-MALLs等对其结构和热学性能进行了表征.分子量检测结果表明,HO-P(LA-co-PDO)-OH的分子量随原料中PDO/LA摩尔比的减小而增大.     

壳聚糖修饰的PLGA纳米粒作为蛋白多肽类药物载体的研究

采用溶剂挥发法,以乳酸羟基乙酸共聚物(PLGA)制备了载牛血清白蛋白(BSA)的PLGA纳米粒(PLGA NP),采用两种修饰方式(直接吸附法和共价交联法)以壳聚糖(chitosan,CS)修饰纳米粒表面,通过考察修饰方法对纳米粒的理化性质、释药性质以及对BSA构型的影响,吸附法修饰的纳米粒(ADCS NP)包封率提高...     

含纳米银的明胶/壳聚糖纳米纤维的制备及其抗菌性能研究

以浓度为88%的甲酸溶液作为纺丝溶剂,采用静电纺丝和紫外光照射还原的方法制备了含纳米银颗粒的明胶/壳聚糖纳米纤维。研究发现,壳聚糖的加入量低于明胶质量的3/16时可以得到纳米纤维,纤维平均直径随着硝酸银加入量的增大而减小,纤维表面纳米银的平均直径随着硝酸银加入量的增大而增大,在纺丝体系中硝酸银的加入量存在一个极限值。所制得含纳米银的明胶/壳聚糖纳米纤维对金黄色葡萄球菌和绿脓杆菌具有较好的抑菌性能,纺丝时加入1%硝酸银制得纳米纤维膜的抑菌率达到99%以上,这种抗菌型纳米纤维可以应用于医用敷料等领域。     

The development of dimple-shaped chitosan carrier for ethambutol dihydrochloride dry powder inhaler

Objective: In this study, a dimple-shaped chitosan carrier was developed for delivering the antituberculosis drug ethambutol dihydrochloride (EDH) from a dry powder inhaler (DPI) to the lungs.

Materials and methods: Nanosized drug particles were prepared using nanospray drying. The microsized carrier was developed from a chitosan solution by spray drying. Five formulations were prepared by physically mixing the drug and carrier in different ratios. The physico-chemical properties of the formulations were analyzed using scanning electron microscopy, differential scanning calorimetry, Fourier transform infrared spectroscopy, ultracentrifugation and a cascade impactor.

Result and discussion: The EDH size was 222?nm and the chitosan carrier size was 1.2?µm. Five formulations, i.e. 1:2, 1:2.5, 1:3.3, 1:5 and 1:10 w/w of the EDH to chitosan carrier were prepared by physical mixing. The chitosan carrier was spherical in shape with a dimpled surface and this provided shallow cavities to which the drug was bound, both within its grooves as well as on its surface. The median adhesion force (50% of drug detachment) for formulations #1 to #5 was between 122 and 993?µN. The mass median aerodynamic diameter of the EDH was between 2.3 and 2.7?μm, with the fine particle fractions (aerosolized particles less than 4.4?μm) of 32–42% of the nominal dose.

Conclusion: We suggest that ethambutol dihydrochloride mixed with a chitosan carrier was suitable for use in a dry powder inhaler for controlling tuberculosis especially in minimizing the risk of multidrug resistant tuberculosis and the possible side effects from EDH.