聚合物材料表面纳米条纹对生物细胞生长的影响

20世纪 80年代后期 ,工程学科与生命学科的交叉融合产生了组织工程学 [1,2 ] ,细胞与生物材料之间的相互作用是组织工程学的一个主要领域 .细胞必须与材料发生适当的粘附 ,才能进行迁移、分化和增殖 ,细胞与材料粘附及随后的扩散能力的大小主要由材料表面的物理和化学性质所决定 [3,4 ] .目前 ,材料表面改性以提高细胞粘附力是组织工程学的一大难题 .聚苯乙烯 (PS)以其无毒、高透明度、低成本以及易加工等性能 ,被广泛应用于基础医学研究及临床医学实验 [5,6 ] .未改性 PS的生物相容性较差 ,只有表面改性后才能用于细胞培养 .目前文献报道…     

丝素蛋白修饰改性的聚羟基脂肪酸酯支架上人体平滑肌细胞的生长

聚三羟基丁酸脂和聚三羟基己酸脂的共聚物(PHBHH_x)是一种具有良好强度和韧性的生物可降解高分子材料, 可作为组织工程心脏瓣膜支架的选择材料之一. 但其生物相容性尚不甚理想. 为此, 本工作利用丝素蛋白修饰改性高分子多孔支架, 以提高支架的生物相容性. 并将人体平滑肌细胞接种在该复合支架上进行体外培养, 以证实改性效果. 其中, 用3-(4,5-二甲基噻唑-2)-2,5-二苯基四氮唑溴盐(MTT)方法测试细胞生长, 评估复合支架的细胞相容性. 并用扫描电子显微镜观察细胞在支架上的生长形态. 结果显示, 丝素蛋白修饰改性后的复合支架更有利于细胞的粘附与生长, 平滑肌细胞在支架上表现出良好的生长形态. 这表明, 丝素能够改善多孔支架的生物相容性, 使PHBHH_x/丝素蛋白复合物能更适宜作为组织工程心脏瓣膜的支架材料. 结果对于进一步研究细胞外间质在复合支架上的生长以及体外培养的组织重建有重要的参考意义.     

角膜基质细胞在p(HEMA-MMA)改性前后的粘附率、形貌与力学性能变化

采用原子力显微镜(AFM)对改性前后材料表面粘附生长的角膜基质细胞的亲和力、三维形貌和力学性能进行了分析。结果显示,改性后材料的细胞亲和力有较大改善,且材料表面细胞三维形态更加正常,铺展更为舒展,与材料的接触面积较大。细胞力学性能分析也发现改性后材料表面细胞具有更高的粘附力和杨氏模量,以及更低的硬度,说明未改性p(HEMA-MMA)材料具有明显的细胞毒性,这种毒性作用导致在其表面生长的细胞的细胞骨架遭到破坏,细胞健康状态明显不如改性后材料表面细胞。因此,改性后的Col/bFGF-p(HEMA-MMA)更适合作为人工角膜材料使用。     

血液相溶材料的合成研究(Ⅶ)──一类新的抗血小板粘附高分子材料

不凝血性 (Nonthrombogenicity)又称抗凝血性 (Antithrombogenicity) ,是指材料不会触发血液凝固的能力 .如何提高不凝血性一直是高分子生物材料研究的主要任务和中心内容 [1～ 3 ] .但目前抗凝血性最好的三类抗凝血材料 ,即聚乙二醇衍生物 (PEO)、聚磷酰胆碱及肝素化材料等 [4～ 10 ] 仍不能满足心血管医用装置的需要 .材料界面血小板的粘附和活化是导致凝血的重要因素 .活化的血小板不仅可激活多种凝血因子 ,也是材料表面血栓的重要组成部分 .因此 ,对材料界面血小板粘附行为的研究可初步评价材料的血液相容性 [11,12 ] .根据“维持正常…     

柠檬酸钆配合物对宫颈癌细胞作用的蛋白质组学研究

为研究稀土化合物抗癌作用及其机制,本文采用差异蛋白质组学方法研究钆对宫颈癌细胞(HeLa)的作用,以四噻唑蓝比色法(MTT法)检测柠檬酸钆配合物([Gd(Cit)2]3-)对HeLa细胞生长的影响,并用Hoechst 33258染色法观察细胞凋亡形态,利用双向凝胶电泳技术分离[Gd(Cit)2]3-作用HeLa细胞前后的蛋白,经图像分析后对蔗异点,进行MALDI-TOF-MS鉴定和数据检索.结果表明0.005～1 mmol·L-1浓度范围内的[Gd(Cit)2]3-对HeLa细胞生长的影响存在浓度依赖性.Hoechst 33258染色结果表明0.07 mmol·L-1[Gd(Cit)2]3-作用24 h对HeLa细胞的生长的抑制率为34%.质谱共鉴定出12个差异表达蛋白质点,包括延伸因子2、过氧化酶6、亲环蛋白A、烯醇酶1等在细胞中分别参与蛋白质转录与翻译、氧化应激、信号传导等过程的蛋白质.提示[Gd(Cit)2]3-可能通过调节胞内氧化应激水平,介导与调控信号转导与蛋白质表达等,从而诱导HeLa癌细胞凋亡.     

重氮树脂与牛血清白蛋白共价结合自组装膜及其表面细胞培养

细胞支架作为组织工程的组成部分为细胞生长提供了最佳微环境 ,并对细胞生长与功能进行控制 .由于细胞对支架表面的生物识别是细胞附着、生长和增殖的基本前提 ,所以对材料表面的功能化是一个重要的课题 [1,2 ] . Shoichet等 [3 ] 通过化学反应或等离子体处理的方法 ,将蛋白质引入到材料表面而使其功能化 .基片在两种带有相反电荷的聚电解质溶液中交替吸附 ,其表面形成致密有序的超薄自组装膜 ,这种层 -层自组装技术不仅制备方法简单 ,无需特殊的设备 ,而且对膜组成和厚度能随意调控 ,以水为介质 ,对环境友好 [4～ 6] ,无疑是一项重要的表…     

微纳米图案化表面对细胞行为的影响

在再生医学领域中,材料对细胞生长和组织修复的调节作用一直是极为关键的问题.随着表面图案化技术的发展,在材料表面制备规则、可控、种类多样的图案化区域成为可能,因而该技术被广泛应用于再生医学、组织工程以及细胞诊断等相关学科领域.通过微纳米表面图案化方法,改变材料的化学性质和拓扑结构,从而实现对细胞粘附、迁移、增殖、凋亡、基...     

新型介孔羟基磷灰石/壳聚糖-万古霉素药物释放系统复合材料的制备及体外抗菌和成骨能力

采用冷冻干燥法合成了介孔羟基磷灰石(HA)/壳聚糖(CS)-万古霉素(VCM)药物释放系统复合材料, 利用SEM, XRD和FTIR等方法对材料进行了表征. 结果证实CS与HA混合复合材料具有良好的孔径和孔隙率, 万古霉素吸附于复合材料的表面和内部. 细胞毒性实验[噻唑蓝(MTT)比色法]结果表明, 材料可以促进成骨细胞增殖且具有良好的细胞相容性. 体外抑菌实验结果证实此材料可长时间抑制耐甲氧西林金葡菌(MRSA)的生长, 具有良好的抑菌和杀菌能力. 细胞黏附实验结果表明, 成骨细胞附着于材料表面增殖并通过孔道延伸. 实时聚合酶链式反应(RT-PCR)实验结果表明, 在成骨相关标志产物胶原蛋白-1(COL-1)及骨形态发生蛋白-2(BMP-2)基因上均有较高的表达, 表明材料在体外可以促进成骨细胞生长, 具有良好的成骨能力.     

细胞相容性聚氨酯的合成及其细胞相容性研究

在紫外光和过氧化氢的共同作用下,过氧化氢基团被引人到聚氨酯膜(PU)表面.将丙烯酸羟乙酯(HEA)吸附于氧化后的PU膜表面,在紫外光下实现了膜表面的接枝,并考察了接枝膜的表面性能.人体脐带静脉内皮细胞粘附和生长的研究表明,HEA接枝后的PU表面细胞粘附率显著提高,细胞的生长速率加快,增值率提高.     

含有邻苯二酚基团的材料在抗菌防污领域的研究进展

贻贝是海洋污损生物中最为常见的一类生物,它可以粘附在几乎所有材料的表面,这是由于贻贝能够分泌具有优异粘附性能的贻贝粘附蛋白.贻贝粘附蛋白结构中具有邻苯二酚基团,并已被证明是一种有效的表面改性锚定剂,几乎可以粘附在任何材料表面.本文针对含有邻苯二酚基团的材料,结合近五年的国内外研究报道,介绍了含有邻苯二酚基团材料的制备方...     

Protein immobilization on the surface of poly-L-lactic acid films for improvement of cellular interactions

To covalently immobilize gelatin or collagen type I on poly-L-lactic acid (PLLA) film surfaces poly(hydroxyethyl methacrylate) (PHEMA) or poly(methacrylic acid) (PMAA) was grafted via photooxidization and subsequent UV-induced polymerization [Makromol. Chem. 186 (1985) 1533.1]. For films grafted with PHEMA, methyl sulfonyl chloride was used to activate the hydroxyl groups and for films grafted with PMAA 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide was used to activate the carboxyl groups. Gelatin and collagen were finally reacted with the activated hydroxyl or carboxyl groups to obtain covalently immobilized protein layers. Grafting of PHEMA, PMAA and protein on the surfaces was confirmed using ATR-IR and XPS. Surface wettability of the modified films was improved. The protein immobilized PLLA may be widely used as a biocompatible material.     

采用层层自组装与光化学修饰法在聚氨酯表面固定生物多糖衍生物

采用层层自组装技术与光化学修饰方法相结合在聚氨酯材料表面固定生物多糖衍生物,首先合成具有光反应活性的叠氮壳聚糖,再在聚氨酯基材表面进行叠氮壳聚糖与香菇多糖硫酸酯的层层自组装,然后通过光化学反应对自组装多层膜修饰层进行交联,制备得到生物多糖衍生物层层自组装与光化学表面修饰的聚氨酯材料.通过红外光谱、X射线光电子能谱、水接触角测量仪、抗菌活性测试、溶血试验和血小板黏附测试等方法对被修饰聚氨酯材料的表面性能和生物性能进行了分析,测试结果表明修饰后的聚氨酯材料表面的亲水性和血液相容性得到改善,并且被修饰材料对大肠杆菌具有良好的抑制效果.     

Hydrophilic dual‐responsive magnetite/PMAA core/shell microspheres with high magnetic susceptibility and ph sensitivity via distillation‐precipitation polymerization

A facile and effective approach to preparation of dual‐responsive magnetic core/shell composite microspheres is reported. The magnetite(Fe₃O₄)/poly(methacrylic acid) (PMAA) composite microspheres were synthesized through encapsulating γ‐methacryloxypropyltrimethoxysilane (MPS)‐modified magnetite colloid nanocrystal clusters (MCNCs) with crosslinked PMAA shell. First, the 200‐nm‐sized MCNCs were fabricated through solvothermal reaction, and then the MCNCs were modified with MPS to form active vinyl groups on the surface of MCNCs, and finally, a pH‐responsive shell of PMAA was coated onto the surface of MCNCs by distillation‐precipitation polymerization. The transmission electron microscopy (TEM) and vibrating sample magnetometer characterization showed that the obtained composite microspheres had well‐defined core/shell structure and high saturation magnetization value (35 emu/g). The experimental results indicated that the thickness and degree of crosslinking of PMAA shell could be well‐controlled. The pH‐induced change in size exhibited by the core/shell microspheres reflected the PMAA shell contained large amount of carboxyl groups. The carboxyl groups and high saturation magnetization make these microspheres have a great potential in biomolecule separation and drug carriers. Moreover, we also demonstrated that other magnetic polymeric microspheres, such as Fe₃O₄/PAA, Fe₃O₄/PAM, and Fe₃O₄/PNIPAM, could be synthesized by this approach. © 2011 Wiley Periodicals, Inc. J Polym Sci Part A: Polym Chem, 2011.     

Efficient One-Step Passivation of Polyurethane Using Transurethanization

The uncontrolled accumulation of biological materials on the surface of medical devices through protein adsorption or cell adhesion causes adverse biological reactions in the living host system, leading to complications. In this study, poly(ethylene glycol) (PEG) is successfully grafted onto polyurethane (PU) surfaces by using a new strategy through a simple and efficient transurethanization reaction. The PEG hydroxyl group is deprotonated and then reacted with the PU surface to provide antiadhesive hydrophilic surfaces in a single step. Surface analysis techniques proved the grafting to be efficient and the formation of a hydrophilic polymeric layer at the surface of PU. Biological assays showed that the surface modification induced lower protein adsorption, cell, platelet, and bacterial adhesion than untreated surfaces, showing a potential for biomedical applications.     

Chemical graft polymerization of sulfobetaine monomer on polyurethane surface for reduction in platelet adhesion

Surface modification is an effective way to improve the hemocompatibility and remain bulk properties of biomaterials. Recently, polymer tailored with zwitterions was found having good blood compatibility. In this study, the zwitterionic monomer of sulfobetaine was graft polymerized onto polyurethane (PU) surface in a three-step heterogenous system through the vinyl bonds of acrylic acid (AA) or hydroxyethyl methacrylate (HEMA), which was immobilized with hexamethylene diisocyanate (HDI) beforehand. First, PU was activated with isocyanate groups using HDI as coupling agent. Second, AA or HEMA was introduced through reaction of AA or HEMA with NCO groups bonded on PU surface. Last, zwitterionic monomer of sulfobetain was graft polymerized with vinyl group of AA or HEMA using AIBN as polymerization initiator. The reaction process was monitored with ATR-IR spectra and XPS spectra. Variation of graft yield with temperature and monomer feed concentration was investigated and feasible conditions were optimized. The wettability of films was investigated by water contact angle measurement and water absorbance. Platelet adhesion experiment was conducted as a preliminary test to confirm the improved blood compatibility of PU. The number of platelets adhering to PU decreased greatly comparing with the originals after 1 and 3 h of contact with human plate-rich plasma (PRP).     

高分子复合物固定化纤维素酶的研究

<正> 固定化酶是将水溶性的酶用物理或化学方法处理,使之变成不溶于水的仍具有酶活性的酶衍生物。在催化反应中,它以固相状态作用于底物。固定化酶不但仍然具有酶的高度专一性及温和条件下高效率催化的特点,还可反复使用。这样,酶经固定后,稳定性有较大增加,可贮藏较长时间。 用高分子复合物固定生物酶是固定化酶的一个新的尝试。两种不同的高分子链通过氢键力、库伦力、范德华力、疏水键力等所谓次价键而聚集成高分子复合物。高分子复合物具有一些特殊功能,如优良的质量传递性能、对水、电解质的灵敏介电特性,对氧和水     

Swelling of poly(methacrylic acid) gels and adsorption of L-lysine and its polymer on the gels

Poly (methacrylic acid) gels (PMAA gels) of various degrees of crosslinking were prepared and the dissociation behavior of these gels was examined; the swelling behavior was investigated as a function of the solution pH values. A reentrant phenomenon of swelling was observed and interpreted based on the Flory-Huggins equation and the Donnan equilibrium formula. Moreover, adsorption of L-lysine, oligo(L-lysine)s (Lys-n,n=3, 9, and 19) and poly(L-lysine) onto PMAA gels from aqueous solutions was investigated under different conditions of pH and concentration of adsorbate. The adsorption ratio of L-lysine onto PMAA gel is dependent on both the pH of solution and the degree of crosslinking. In a pH range between 8 and 9, the protonated form of L-lysine is strongly adsorbed on the PMAA gel by electrostatic interactions. Oligomers and polymer of L-lysine are adsorbed in a somewhat different way from the monomeric L-lysine. In addition, the desorption behavior of L-lysine from PMAA gels by a change in pH was also investigated.     

Enhancement of Fatty Acid‐based Polyurethanes Cytocompatibility by Non‐covalent Anchoring of Chondroitin Sulfate

For tissue engineering purpose biopolymer chondroitin sulfate (CS), one of the major components of cartilage and bone extracellular matrix, was immobilized onto the surface of amino‐functionalized polyurethane (PU) films derived from naturally occurring oleic and 10‐undecenoic acids. The amino‐functionalized PUs were prepared by aminolysis with 1,6‐hexamethylenediamine of synthesized PUs containing methyl ester groups. FTIR‐ATR, XPS, SEM, and water contact angle measurements were used to confirm the surface changes at each step of treatment, both in morphologies and chemical composition. Cytotoxicity and cell morphology analysis using osteoblast cell line MG63 showed that PU‐CS films are suitable materials for cell growth, spreading, and differentiation.

     

Stability of modified surface CaCO3 in the non-polar medium

The adsorption isotherm of methacrylic acid (MAA) and polymethacrylic acid (PMAA) molecules on CaCO₃ were studied. The isotherm of (MAA) adsorption from cyclohexane was found formed from two steps, while that of (PMAA) from ethanol is formed from one step. The effects of surface modification of CaO₃ with (MAA) and (PMAA) in the sedimentation properties in a non-polar medium (cyclohexane) have been studied. It was found that the most stable suspension formed is concerned with monolayer surface coverage for the two adsorptives. Also, studies were made for the rheological properties of concentrated suspension of CaCO₃ modified with (MAA) and (PMAA) in a paraffin oil. The equilibrium flow curves of CaCO₃ modified with (PMAA) suspensions exhibit pseudoplastic characteristics, accompanied by some degree of complex thixotropy, while that modified with (MAA) exerts a thickening effect with rheopexy characteristics.