羟乙基与N-琥珀酰羟乙基壳聚糖的制备表征及细胞毒性试验

壳聚糖（chitosan,CTS）与氯乙醇反应制备羟乙基壳聚糖（hydroxyethyl chitosan,HECTS）,并接合琥珀酸酐合成N-琥珀酰羟乙基壳聚糖（N-succinyl-hydroxyethyl chitosan,Suc-HECTS）,考察琥珀酰化度的影响因素确定最适反应条件。用FT-IR对产物进行结构表征,1 H NMR测定脱乙酰度和琥珀酰化度,元素分析法测定羟乙基取代度,并评价了HECTS和Suc-HECTS的细胞毒性。结果表明HECTS与Suc-HECTS均无细胞毒性。在生物医药和药物载体方面的应用提供了一定的理论基础。     

羟乙基壳聚糖接枝聚乳酸的合成与表征

首先采用壳聚糖(CS)与2-氯乙醇反应制备了羟乙基壳聚糖(HECS),然后通过本体开环聚合法,以辛酸亚锡为催化剂,CS和HECS为大分子引发剂引发消旋-丙交酯开环聚合制备了一系列CS-g-PDL-LA和HECS-g-PDLLA共聚物,用FTIR、1HNMR、XRD、TG和溶解实验对产物的结构与性能进行了分析表征。结果表明,与CS相比,HECS明显具有较高的反应活性,当n(D,L-LA):n(aminoglucoside)投料比从10:1增大到40:1,对应CS-g-PDLLA和HECS-g-PDLLA共聚物的接枝率分别从24.01%和77.42%上升到114.85%和380.51%,而两者中的聚乳酸侧链上的平均乳酰单元数也相应从0.61和2.51分别上升到2.48和12.31。另外,原料投料比对共聚物的组成与性能有显著影响,随n(D,L-LA):n(ami-noglucoside)值增大,共聚物的接枝率和聚乳酸侧链上的平均乳酰单元数也逐渐增大,共聚物的结晶性能下降,起始热分解温度有所降低。与CS-g-PDLLA相比,HECS-g-PDLLA在常用有机溶剂中的溶解性能有所改善。     

不同脱乙酰度壳聚糖接枝丙烯酰胺DMC絮凝剂的合成与表征

以不同脱乙酰度壳聚糖,丙烯酰胺和二甲丙烯酰氧基乙基三甲基氯化铵（DMC）为原料,选择过硫酸铵-亚硫酸氢钠为氧化还原体系引发剂,EDTA-2Na作为金属离子螯合剂,合成了壳聚糖接枝丙烯酰胺DMC聚合物;通过红外光谱,电镜扫描对聚合物进行结构表征,结果表明壳聚糖结构发生了变化,通过在相同条件下比较壳聚糖不同脱乙酰度对接枝率的影响,得出了在脱乙酰度为68.5%时聚合物的接枝率最大为250%,其最佳合成工艺为：m（壳聚糖）∶m（丙烯酰胺）∶m（DMC）=1∶5∶5,引发剂用量为体系质量分数的0.3%～0.4%,其中m（过硫酸铵）∶m（亚硫酸氢钠）=1∶1,温度55 ℃～60 ℃,反应时间为2.5 h～3 h.     

聚乳酸/壳聚糖复合材料的制备及性能研究

目的 以聚乳酸 （PLA） 为基材,与壳聚糖 （CTS） 相结合制备抗菌复合材料。方法 通过熔融挤出复合工艺制备全生物降解抗菌复合材料, 考察壳聚糖对复合材料力学性能和抗菌性能的影响。结果 复合材料的拉伸强度和弯曲强度随着壳聚糖质量分数的增加而略有降低的趋势, 其缺口抗冲击强度基本不受壳聚糖的影响, 断裂伸长率则呈现先上升后减小的趋势。当壳聚糖质量分数为4%时, 复合材料具有较佳的综合力学性能。当壳聚糖的质量分数为8%时, 复合材料具有较明显的抗菌能力。结论 全生物降解聚乳酸壳聚糖复合材料具有广阔的应用前景, 尚需要继续深入探讨两者之间的关系,以制备性能更加优良的全生物降解型材料。     

壳聚糖与丙交酯接枝共聚物的制备与表征

壳聚糖与聚乳酸是具有良好生物相容性的高分子材料,目前被广泛用于生物医学材料,特别是作为组织工程支架.本文以壳聚糖为原料,经过改性制备6-O-三苯甲基-2-邻苯二甲酰基-壳聚糖,作为大分子引发剂,以辛酸亚锡催化D,L-丙交酯接枝聚合,制备共聚物大分子.采用傅立叶变换红外光谱、核磁共振氢谱、碳谱对其结构进行表征,证实了共聚物的生成.热分析测试表明,共聚物具有不同于聚乳酸的热特性,熔点152.8℃.接触角测试表明共聚物具有较好的亲水性.凝胶色谱测定不同反应物配比对共聚物分子量的影响.壳聚糖与丙交酯的接枝共聚物具有较聚乳酸及壳聚糖更为优良的性能,可作为组织工程支架材料.     

N,O-羧乙基壳聚糖的合成及对金属离子的吸附性能

利用壳聚糖与氯丙酸反应,制备了N,O-羧乙基壳聚糖,采用FT-IR、XRD和TGA等手段对其结构进行了表征。结果表明,在N aOH质量分数为15%和反应温度为60℃的条件下,脱乙酰度为90%的壳聚糖与3-氯丙酸(原料比1∶1.5)反应3 h,可制得取代度达0.83的羧乙基壳聚糖。对铜、钴、镍、锌、镉、汞、铅等七种金属离子吸附性能研究发现,羧乙基壳聚糖比壳聚糖有更好的吸附性能。     

壳聚糖-聚乳酸接枝共聚物的制备与表征EI北大核心

将醛基化改性的聚乳酸接枝到壳聚糖,并通过元素分析、红外光谱(IR)、核磁共振(1H-NMR)、X射线衍射(XRD)和热重分析(TG)分别对接枝产物的接枝率、结构和结晶性能进行表征。IR和1H-NMR结果表明聚乳酸成功接枝到壳聚糖主链,不同投料比和接枝率的关系与元素分析一致;PLLA-CHO/CS-NH2最佳摩尔比为1∶2.5,此时的接枝率为52.22%;XRD和TG结果表明接枝产物的结晶度和热分解温度降低,说明壳聚糖的高结晶性得到改善,其应用范围扩大。     

壳聚糖-聚乳酸接枝共聚物的制备与表征

以L-乳酸和壳聚糖为原料,辛酸亚锡为催化剂,通过原位聚合法制备了含聚乳酸链段的壳聚糖接枝共聚物,讨论了原料投料比、催化剂浓度对接枝率的影响。通过红外光谱对共聚物化学结构进行分析,并通过热重分析研究其热失重行为。与壳聚糖相比,聚乳酸支链的引入有效削弱了壳聚糖分子的氢键作用,共聚物起始分解温度和热稳定性下降。     

羟乙基纤维素/壳聚糖涂膜液对蓝莓的保鲜效果研究

以羟乙基纤维素和壳聚糖为原料制备新型共混涂膜液,以其对蓝莓进行涂膜保鲜处理,并与以壳聚糖涂膜液处理及未作处理的蓝莓进行对比,研究共混涂膜液对蓝莓贮藏期间品质的影响.结果表明:共混涂膜液能够有效地降低蓝莓的失重率和腐烂率,在贮藏后期,能够减缓果实硬度的下降速度;采用共混涂膜液处理后,果实的可溶性固形物含量、Vc含量以及花青素含量均呈现出最小的变化.     

组氨酸改性壳聚糖多孔支架的制备与表征

以1-(3-二甲氨基丙基)–3-乙基碳二亚胺为引发剂,N-羟基琥珀酰亚胺为催化偶联剂,将组氨酸接枝到壳聚糖上,通过改变组氨酸/壳聚糖的物质的量比及壳聚糖的相对分子质量制得不同取代度的N-组氨酸壳聚糖(NHCS)。利用红外光谱(FT-IR)、核磁共振(1H-NMR)、元素分析(EA)、热重分析(TGA)等进行表征。结果表明,随着组氨酸/壳聚糖的物质的量比增大,取代度增高,NHCS支架材料孔径增大,孔径尺寸分布在5μm～120μm之间,孔隙率均大于85%,可以满足组织工程支架材料的要求。随着pH增大,NHCS的Zeta电位从+13.5 mV降至-22.7 mV,表明其具有pH响应性。当组氨酸/壳聚糖的物质的量比为0.5时制得的NHCS支架材料孔径均一,可为生物矿化提供良好的模板。     

柞蚕丝素/壳聚糖共混膜的结构及细胞相容性

用碳化二亚胺(EDC)作为交联剂,流延法制备柞蚕丝素(ASF)/壳聚糖(CS)共混膜。用扫描电镜(SEM)、红外光谱(FT-IR)、热重分析(TG)和四甲基偶氮唑盐比色法(MTT)对膜的结构及细胞相容性进行了研究。结果显示,柞蚕丝素和壳聚糖具有较好的相容性和较强的相互作用,壳聚糖能阻碍共混膜内的丝素蛋白形成β-折叠构象。EDC能分别与柞蚕丝素及壳聚糖反应,从而对共混膜进行有效的交联,并使膜的热稳定性提高。与ASF膜或CS膜相比,共混比为80/20和40/60的ASF/CS共混膜更有利于细胞生长和增殖,作为一种新型的生物材料具有良好的研究和开发应用前景。     

等离子体处理偶联胶原提高聚乳酸材料的细胞相容性

本研究通过结合氨气等离子体处理以及胶原改性的方法来改善聚乳酸材料的细胞相容性。水接触角分析表明氨气等离子体处理可以改善聚乳酸材料的亲水性,促进细胞的粘附。光学显微镜以及扫描电镜的分析结果表明,氨气等离子体处理后通过胶原改性可以进一步促进细胞在聚乳酸材料表面的生长。并且,与涂覆胶原相比,偶联胶原可以更好地使胶原蛋白固定在聚乳酸材料表面,从而表现出更好的细胞相容性。     

Poly (D,L-lactic acid)/poly (∈-caprolactone) blend membranes: preparation and morphological characterisation

With the aim of exploring possible application of the concept of blend compatibilisation into the field of biodegradable membranes, a study of the influence of random copolymer poly(D,L-lactide-co--caprolactone) on the properties of corresponding homopolymer blends has been conducted. Blends of plain homopolymers and blends containing 5 and 10 wt% of a copolymer of suitable composition have been prepared in the melt and characterised for their molecular interactions using thermal, dynamic-mechanical, mechanical (tensile tests) and morphological analyses. The blends are characterised by a good dispersion of the poly--caprolactone (PCL) minor phase into the poly(D,L-lactic acid) (PDLLA) matrix and better mechanical properties compared to plain PDLLA, and such characteristics further improve when adding the copolymer. Microporous blend membranes consisting of PDLLA and PCL were then prepared by a phase inversion method and characterised by scanning electron microscopy. The addition of compatibilising agent led to a highly homogeneous structure, while in absence of compatibiliser a clear phase separation occurred.     

微波辐射D,L-丙交酯开环聚合制备聚乳酸

为得到聚乳酸的最佳制备工艺,利用微波辐射技术实现D,L-丙交酯开环聚合制备聚乳酸,实验考查了催化剂种类和用量,微波辐照功率和时间等工艺参数对产物分子量的影响,以及反应过程中体系温度的变化.研究表明,以连续微波炉作为反应器,催化剂Sn(Oct)2用量为丙交酯单体用量的0.56%(质量分数),在功率为90 W的连续微波辐射下反应10 m in,可获得粘均分子量(Mη)为15.92×104的聚乳酸(PDLLA).与家用微波炉相比,采用连续微波炉反应器,可在较短的反应时间内获得较高产率的聚乳酸产物.     

生物可吸收材料PDLLA的聚合条件研究

通过乳酸脱水合成出高纯度的D ,L 丙交酯。以辛酸亚锡为引发剂 ,进行丙交酯开环聚合为聚乳酸 (PDLLA)的实验研究。讨论了D ,L 丙交酯开环聚合的影响因素和PDLLA聚合条件     

Polysaccharide surface engineering of poly(D, L-lactic acid) via electrostatic self-assembly technique and its effects on osteoblast growth behaviours

The objective of this study was to surface modify the poly (D, L-lactic acid) (PDLLA) films and assess the effects of the modified surfaces on the functions of osteoblasts cultured in vitro. A layer-by-layer (LBL) self assembly technique, was used leading to the formation of multilayers on the PDLLA film surfaces. Chitosan (Chi) and poly (styrene sulfonate, sodium salt) (PSS) were utilized as polycation and polyanion in this study, respectively. The layer structure was investigated by using X-ray photoelectron spectroscopy (XPS) and water contact angle measurement, respectively. XPS analysis displayed the presence of chitosan on PDLLA surface. A full coverage of coating with PSS/Chi layers was achieved on the PDLLA surface only after the deposition layers of PEI/(PSS/Chi)₂. These results showed that PDLLA films could be modified with PSS/Chi pairs which may affect the biocompatibility of the modified PDLLA films. To confirm this hypothesis, cell proliferation, cell viability as well as alkaline phosphtase activity of osteoblasts on layer-by-layer modified PDLLA films as well as control samples were investigated in vitro. The proliferation of osteoblasts on modified PDLLA films was found to be greater than that on control (p < 0.05 and p < 0.01) after 1, 4 and 7 days culture, respectively. Cell viability measurement showed that the PSS/Chi modified PDLLA films have higher cell viability (p < 0.01) than control. Osteoblast differentiation function (ALP) on LBL-modified PDLLA film was found significantly higher (p < 0.01) than that of virgin PDLLA films. These data suggests that PSS/Chi pair was successfully employed to surface modify PDLLA film via a layer-by-layer technique, and enhanced its cell biocompatibility.     

水溶性壳聚糖衍生物在壳聚糖膜表面的化学固定及抗凝血性能研究

合成了N-双取代亚甲基磷酸壳聚糖,并且对其进行了表征。通过戊二醛交联的方法将N- 双取代亚甲基磷酸壳聚糖固定在壳聚糖薄膜表面。对接枝前后膜表面的结构性能和血液相容性进行表征,结果显示N -双取代亚甲基磷酸壳聚糖被有效地固定在壳聚糖膜表面,并且能够有效地抑制血小板在壳聚糖膜表面的粘附。     

壳聚糖／大豆分离蛋白复合包装膜的制备与表征

采用壳聚糖(CS)和大豆分离蛋白(SPI)为基材,制备了可降解包装膜。用红外光谱、X射线衍射和扫描电镜对复合包装膜结构进行表征。对复合包装膜的拉伸性能和透光性能进行了测试和分析。结果表明:CS和SPI之间存在一定的相互作用;当SPI质量分数为10%时,复合包装膜的拉伸性能优于纯壳聚糖膜,透光性较纯壳聚糖膜略有下降。     

Extruded Blends of Chitosan and Ethylene Copolymers for Antimicrobial Packaging

Chitosan was melt‐processed with an ethylene methyl acrylate copolymer ionomer and with an ethylene vinyl acetate copolymer to create antimicrobial extruded films. The key to obtaining a successful antimicrobial blend was the use of solid chitosonium acetate that remained after evaporation of water from the chitosan solution. When solid free‐flowing powders of chitosonium acetate were formed by spray drying chitosan solutions, blended in an extruder (at 2.5% and 4% chitosan) with Elvax® 3175 ethylene vinyl acetate copolymer, and extruded through a film die onto a chill roll to form films, the films exhibited antimicrobial activity against Escherichia coli 25922, Salmonella enterica serovar Enteritidis Nal^R, and Listeria monocytogenes Scott A. The log₁₀ reductions in CFU/ml after 24 h in a shake‐flask test were near 2 for films containing 4% chitosan. This melt‐blending/extrusion approach is expected to open applications for chitosan‐based antimicrobial packages and articles that were impossible or impractical with chitosan coatings. Copyright © 2011 John Wiley & Sons, Ltd.