丙烯酸(钠)-壳聚糖吸水树脂的合成

以丙烯酸和壳聚糖为原料,硝酸铈铵为引发剂,N,N-亚甲基双丙烯酰胺为交联剂,在醋酸溶液中合成了丙烯酸壳聚糖吸水树脂。研究了氯化钠、引发剂硝酸铈铵、丙烯酸与壳聚糖配比及交联剂N,N-亚甲基双丙烯酰胺对产物吸水性能的影响,采用正交实验对工艺条件进行了优化。结果表明:氯化钠0.6g、硝酸铈铵96mg、丙烯酸与壳聚糖比例为14.5∶1.5及N,N-亚甲基双丙烯酰胺48mg时合成树脂吸水率最高。     

改性壳聚糖及其膜材料的制备与表征

以壳聚糖(CS)、亚磷酸和多聚甲醛为原料,制备N-亚甲基磷酸化壳聚糖(NPCS)。利用红外光谱和核磁共振波谱表征其结构。CS和NPCS膜对Ca2+的络合性能表明,磷酸化改性的NPCS膜对Ca2+的络合能力大大提高,钙离子的行为与p H有关,络合量随p H值增加而增加,在p H为10时的络合过程符合一级动力学。X射线衍射分析表明磷酸化壳聚糖的结晶度下降,膦改性壳聚糖与Ca2+络合后结晶度提高。原子力显微镜和扫描电镜分析表明,NPCS膜表面较粗糙,有一些圆柱状突起,经钙化后NPCS膜的表面趋于平滑细腻,出现一定螺旋结构的树枝状网络突起,深度为275 nm,螺旋条纹间距约为200~400 nm,这种螺旋状的枝杈网络突起纵横交错在一起形成更厚更致密的覆盖层,使NPCS膜的表面平坦化。     

壳聚糖/聚(N-异丙基丙烯酰胺)全互穿网络水凝胶的制备及性能

以壳聚糖(CS)和N-异丙基丙烯酰胺(NIPAAm)为原料,N,N'-亚甲基双丙烯酰胺(BIS)为交联剂,制备具有温度和pH值双敏感性的全互穿网络水凝胶(Full-IPN);利用红外光谱(FT-IR)对其分子结构进行表征,扫描电镜(SEM)观察其内部形貌,并通过DSC对其低临界溶解温度(LCST)进行表征,最后研究了不...     

胆碱磷酰化偶联壳聚糖仿生衍生物的合成及表征

采用Antherton-Todd反应合成了两种胆碱磷酰化偶联壳聚糖衍生物——带双正电荷的N-二胆碱磷酰化偶联壳聚糖(N-PC+Cs)和两性的N-磷酸胆碱磷酰化偶联壳聚糖(N-PCCs),并用核磁共振波谱(NMR)和红外光谱(IR)表征其化学结构。由1H-NMR谱得到N-PC+Cs的取代度为30.9%,N-PCCs的取代度为32.6%。X射线衍射谱(XRD)和热分析的结果表明,与壳聚糖相比,N-PC+Cs和N-PCCs的结晶性和热稳定性都显著降低。水溶性试验表明,两种仿生衍生物在中性水溶液中都表现出良好的溶解性,有望用于药物/基因传输系统载体。     

N-羧甲基壳聚糖的合成改进及吸附性能

采用氯乙酸替代乙醛酸与壳聚糖反应,以Na2CO3为缚酸剂,合成了N-羧甲基壳聚糖,并采用红外光谱(FT-IR)、核磁共振(1H-NMR和13C-NMR)对其进行表征。考察了N-羧甲基壳聚糖对Ni2+的吸附性能,探讨了N-羧甲基壳聚糖的取代度、溶液初始pH值和吸附时间等因素对吸附量的影响。研究发现,羧甲基化发生在壳聚糖的氨基上。当产品的取代度为1.24时,最佳初始pH值为7,最佳吸附时间为2h,其吸附量为124.5mg/g。FT-IR表征说明羧基和Ni2+发生了配位反应。     

N-琥珀酰壳聚糖的制备及其性能

通常在N-琥珀酰壳聚糖的合成过程中使用大量的有毒溶剂,容易造成环境污染,并且有毒溶剂易残留在产物中,限制了N-琥珀酰壳聚糖在生物医学领域的应用。本研究采用一种安全、环保的合成方法,以无水乙醇为溶剂,通过控制反应时间,合成了一系列不同取代度的N-琥珀酰壳聚糖,测定了产物的取代度,分子量及其分布,并用FTIR对其进行结构分析。采用粉末X-射线衍射、TG对其结晶性能和热稳定性进行分析,并对其水溶性和生物相容性进行了探讨。当反应时间为15 h时,所得产物的取代度最高,分子量最大,分子量分布最窄;N-琥珀酰壳聚糖的结晶性和热稳定性均弱于壳聚糖,改性的壳聚糖具有良好的水溶性。动物皮下植入实验表明,以无水乙醇为溶剂合成的N-琥珀酰壳聚糖具有良好的生物相容性,有望在生物医用材料方面得到广泛应用。     

壳聚糖衍生物改性磷酸锆自组装纳米材料的 制备及抑菌性能研究

以α-ZrP为载体,通过微波辐射法,将3种水溶性壳聚糖衍生物羧甲基壳聚糖、N-三甲基壳聚糖季铵盐和N-对苯甲氧基甲基壳聚糖季铵盐插层进入α-ZrP层间,制备得到3种壳聚糖衍生物/磷酸锆纳米复合抑菌材料。通过红外光谱、X射线衍射、扫描电镜、透射电镜、电动电位分析和热重分析,对纳米复合材料的组成、结构和热稳定性进行表征。X射线衍射及电动电位分析实验结果表明:相较于α-ZrP,壳聚糖衍生物/磷酸锆纳米复合材料的层间距随着壳聚糖衍生物插层而明显增大,壳聚糖衍生物的正电性越强,复合材料的层间距越大,这表明壳聚糖衍生物与α-ZrP通过离子交换、氢键结合,已经成功地插层进入α-ZrP层间。热重分析结果显示复合材料的热稳定性较天然壳聚糖有显著提高。抑菌试验结果表明,复合材料对大肠杆菌和金黄色葡萄球菌都具有很好的抑菌效果。     

明胶固定化改性壳聚糖膜的制备与性能表征

用碳二亚胺缩合剂将明胶固定于壳聚糖膜表面,采用傅立叶红外光谱、X射线光电子能谱表征改性膜的结构,结果显示明胶成功固定于壳聚糖膜表面.透光率、吸水率和接触角测试表明,改性膜的透光率最高可达98%左右,能满足角膜修复对透光性的要求.改性后膜的吸水率提高到97.6%,接触角下降到73.4°,亲水性提高.以壳聚糖膜和明胶固定化改性壳聚糖膜为载体培养人成纤维细胞,结果显示细胞在明胶固定化改性壳聚糖膜上的生长情况优于壳聚糖膜,改性膜具有良好的细胞亲和性.这种明胶固定化改性壳聚糖膜有望成为一种角膜修复材料.     

纤维素/羧甲基壳聚糖共混膜结构与抗菌性能

对壳聚糖羰甲基化修饰合成羰甲基壳聚糖，于纤维素的新溶剂6％（质量）NaOH/4%（质量）尿素中制备出纤维/羧甲基壳聚糖共混膜。实验表明，共混膜中羰甲基壳聚糖含量低于50％（质量）时，二者具有良好的相容性，其干，湿态拉伸强度在羧甲基壳聚糖含量20％（质量）时达到最大，分别为94．5MPa和49.4MPa，比纤维素膜分别提高了13．2％和26％。抗菌性能测试显示，共混膜对金黄色葡萄球菌（St.aureus)的抗菌性大于纤维素膜，并且随羰甲基壳糖含量的增加而增强，羧甲基壳聚糖的取代度在0．4左右时，共混膜具有最佳的抗菌效果。     

新型两亲性N-烷基-N-季铵化壳聚糖衍生物的制备与表征

以天然聚合物壳聚糖为原料,在其2-NH2上引入长链疏水基(n=8,10,12),制得N-烷基壳聚糖,然后在未取代的2-NH2进行季铵化得到两亲性的N-烷基-N-季铵化壳聚糖衍生物。通过FT-IR、13C-NM R、1H-NM R对其结构进行表征;用差示扫描量热法分析了物理性质。两亲性的N-烷基-N-季铵化壳聚糖衍生物可在水中自发形成21 nm~280 nm的胶束。     

Preparation of chitosan films using different neutralizing solutions to improve endothelial cell compatibility

The development of chitosan-based constructs for application in large-size defects or highly vascularized tissues is still a challenging issue. The poor endothelial cell compatibility of chitosan hinders the colonization of vascular endothelial cells in the chitosan-based constructs, and retards the establishment of a functional microvascular network following implantation. The aim of the present study is to prepare chitosan films with different neutralization methods to improve their endothelial cell compatibility. Chitosan salt films were neutralized with either sodium hydroxide (NaOH) aqueous solution, NaOH ethanol solution, or ethanol solution without NaOH. The physicochemical properties and endothelial cell compatibility of the chitosan films were investigated. Results indicated that neutralization with different solutions affected the surface chemistry, swelling ratio, crystalline conformation, nanotopography, and mechanical properties of the chitosan films. The NaOH ethanol solution-neutralized chitosan film (Chi-NaOH/EtOH film) displayed a nanofiber-dominant surface, while the NaOH aqueous solution-neutralized film (Chi-NaOH/H₂O film) and the ethanol solution-neutralized film (Chi-EtOH film) displayed nanoparticle-dominant surfaces. Moreover, the Chi-NaOH/EtOH films exhibited a higher stiffness as compared to the Chi-NaOH/H₂O and Chi-EtOH films. Endothelial cell compatibility of the chitosan films was evaluated with a human microvascular endothelial cell line, HMEC-1. Compared with the Chi-NaOH/H₂O and Chi-EtOH films, HMECs cultured on the Chi-NaOH/EtOH films fully spread and exhibited significantly higher levels of adhesion and proliferation, with retention of the endothelial phenotype and function. Our findings suggest that the surface nanotopography and mechanical properties contribute to determining the endothelial cell compatibility of chitosan films. The nature of the neutralizing solutions can affect the physicochemical properties and endothelial cell compatibility of chitosan films. Therefore, selection of suitable neutralization methods is highly important for the application of chitosan in tissue engineering.     

等离子体表面接枝改性聚对苯二甲酸乙二醇酯的血液相容性研究

利用等离子体表面接枝改性方法在聚对苯二甲酸乙二醇酯(polyethylene terephthalate，PET)材料表面接枝不同分子量的聚乙二醇(PEG)，体外血液相容性实验表明．接枝了PEG的PET材料的血液相容性与PEG的分子量有关；当接枝的PEG分子量达到6000时，材料的血液相容性最好。     

Degradation and compatibility behaviors of poly(glycolic acid) grafted chitosan

The films of poly(glycolic acid) grafted chitosan were prepared without using a catalyst to improve the degradable property of chitosan. The films were characterized by Fourier transform-infrared spectroscopy and X-ray photoelectron spectroscopy (XPS). The degradation of the poly(glycolic acid) grafted chitosan films were investigated in the lysozyme solution. In vitro degradation tests revealed that the degradation rate of poly(glycolic acid) grafted chitosan films increased dramatically compared with chitosan. The degradation rate of poly(glycolic acid) grafted chitosan films gradually increased with the increasing of the molar ratio of glycolic acid to chitosan. Additionally, the poly(glycolic acid) grafted chitosan films have good biocompatibility, as demonstrated by in vitro cytotoxicity of the extraction fluids. The biocompatible and biodegradable poly(glycolic acid) grafted chitosan would be an effective material with controllable degradation rate to meet the diverse needs in biomedical fields.     

HECS-g-PDLLA共聚物的微波合成及与聚乳酸的相容性

在微波作用下,以辛酸亚锡为催化剂,羟乙基壳聚糖（HECS）为大分子引发剂引发D,L-丙交酯（D,L-LA）开环聚合制备羟乙基壳聚糖-g-聚乳酸（HECS-g-PDLLA）,通过红外（IR）、元素分析（EA）、氢核磁共振（1H-NMR）、X射线衍射（XRD）和差示扫描量热分析（DSC）对产物进行了表征。然后采用溶液共混法...     

Electrode coatings based on chitosan scaffolds

Thin films of a biopolymer chitosan (CHIT) were cast on glassy carbon electrodes, modified by grafting Lucifer Yellow VS dye (LYVS) onto chitosan chains, and cross-linked with glutaric dialdehyde (GDI). The ion-transport and ion-exchange properties of such polymeric structures (CHIT, CHIT-LYVS, CHIT-LYVS-GDI) were studied using cyclic voltammetry, rotating disk electrode, and flow injection analysis. The results showed that the chitosan matrix supported a fast ion transport as demonstrated by aqueous-like values of the apparent diffusion coefficients of Ru(NH3)6(3)+ and dopamine in the films. Anionic LYVS dye introduced a permselectivity against anions (e.g., Fe(CN)6(4)-, ascorbate) into the CHIT-LYVS films. The cross-linking of such films with GDI further increased their permselectivity as well as their stability. A unique combination of high permselectivity and fast ion transport in the CHIT-LYVS-GDI films is discussed in terms of the mixed-transport mechanism involving both pore and membrane diffusion in a highly hydrated chitosan matrix. The results indicate that the chemically modified chitosan is an attractive new coating for the development of fast, selective, and reversible sensors.     

Physical properties and molecular behavior of chitosan films

Chitosan films, varying in molecular weight and degree of deacetylation, were prepared by a casting technique using acetic acid as a dissolving vehicle. The physicochemical properties of the films were characterized. Both molecular weight and degree of deacetylation affected the film properties. Powder X-ray diffraction patterns and differential scanning calorimetry thermograms of all chitosan films indicated their amorphous state to partially crystalline state with thermal degradation temperature lower than 280-300°C. The increase in molecular weight of chitosan would increase the tensile strength and elongation as well as moisture absorption of the films, whereas the increase in degree of deacetylation of chitosan would either increase or decrease the tensile strength of the films depending on its molecular weight. Moreover, the higher the degree of deacetylation of chitosan the more brittle and the less moisture absorption the films became. All chitosan films were soluble in HCl-KCl buffer (pH 1.2), normal saline, and distilled water. They swelled in phosphate buffer (pH 7.4), and cross-linking between chitosan and phosphate anions might occur. Finally, transmission infrared and ¹³C-NMR spectra supported that chitosan films prepared by using acetic acid as a dissolving were chitosonium acetate films.     

肝素和聚氨酯同溶液体系混合接枝及其抗凝血性

利用全新的四氢呋喃和水的溶液体系将肝素与不溶于水的聚氨酯同溶液混合,制备出含有肝素的聚氨酯薄膜利用碳二亚胺缩合反应将肝素接枝在聚氨酯分子上以改善材料的长效抗凝血性.在肝素过量的情况下,制备出同时含有游离和接枝肝素的聚氨酯薄膜,并初步评价了薄膜中肝素的扩散速率以及体外抗凝血性.结果表明,肝素均匀分布在薄膜中,肝素活性保持良好,扩散缓慢,具有相对长效的抗凝血活性.接枝后的肝素仍具有良好的生物活性,同时含有接枝和游离肝素薄膜的抗凝血性优异.     

The fabrication and property of hydrophilic and hydrophobic double functional bionic chitosan film

A new kind of hydrophobic bionic chitosan film was fabricated by simulating the surface structure of lotus leaf. The titanium oxide nanotube array was used as templates. Scanning electron microscopy (SEM) images show that one side of this films have nano-scale rough surface with spherical protrusions alike the surface of lotus leaf. The diameter of the protrusions is about 100 nm, which is equal to diameter of the titanium oxide nanotube. The water contact angle of chitosan films is up to 120 degrees and it is hydrophobic. The other side of the film is flat and the contact angle is 70 degrees. That indicated that the hydrophilism of natural materials is connected with the surface structures. The double functional chitosan films, one side is hydrophilic, the other is hydrophobic, can be made by an easy method. This method is non-toxic and clean. The double functional chitosan film will improve the application of chitosan films in medicine.     

明胶-壳聚糖复合膜的制备与性能

制备了一系列不同配比的明胶-壳聚糖复合膜,研究了壳聚糖含量对复合膜力学性能、吸湿性能的影响,通过X射线衍射和红外光谱分析了复合膜的结构。结果表明,复合膜及纯壳聚糖膜的断裂伸长率和拉伸强度均大于纯明胶膜,壳聚糖的加入可改善膜的力学性能。随壳聚糖含量的增加,复合膜的吸湿率增大。明胶与壳聚糖分子间存在较强的相互作用,与明胶共...     

Enzyme activity of horseradish peroxidase immobilized in chitosan matrices in alternated layers

The successful immobilization of enzymes such as horseradish peroxidase (HRP) in solid films is essential for applications in sensors and for fundamental studies aimed at identifying possible biotechnological devices. In this study we show that HRP can be immobilized in alternated layers with chitosan as the template material. The activity of HRP in HRP/chitosan films was preserved for several weeks, and could be detected optically upon monitoring the reaction with pyrogallol. The morphology of the film displayed stripes that disappeared after reaction with pyrogallol. Though the activity in the HRP/chitosan film was lower than in a homogeneous solution or in an LB film investigated earlier, the response was linear for a considerable period of time, which may be advantageous for sensing hydrogen peroxide.