IMMOBILIZATION OF YEAST CELLS IN SEVERAL CONDUCTING POLYMER MATRICES

ABSTRACT

Immobilization of yeast cells (Saccharomyces cerevisiae) in different polymer matrices was performed by constant potential electrolysis. These matrices were polypyrrole (PPy); poly(methyl methacrylate)/polypyrrole (PMMA/PPy) and thiophene-capped poly(methyl methacrylate)/polypyrrole (TPMMA/PPy). The characterization of PMMA/PPy copolymer was achieved by Fourier-transform Infrared Spectroscopy (FT-IR), Differential Scanning Calorimetry (DSC) and Scanning Electron Microscopy (SEM). The invertase activity of immobilized yeast cells was determined. Optimum temperature, Michaelis-Menten constants and maximum reaction rates of the enzyme electrodes were compared with those of free yeast cells. The operational and storage stabilities of three different immobilization systems were analyzed.     

离子交换树脂药物载体在给药系统中的应用

离子交换树脂作为药物传递系统的有效载体,由于具有多种优良特性,已经受到药剂学家们的高度关注。本文就缓释、控释给药、靶向给药、离子导入透皮、鼻腔、眼部给药、胃漂浮剂给药、掩盖药物苦味和脉冲给药等方面在药剂学中的应用研究进行了概述。     

热磁双重响应性载药微囊的制备及其性能研究

采用LbL模板技术,将天然聚电解质壳聚糖CS和海藻酸钠ALG、磁性纳米颗粒Fe3O4或带负电荷或双亲性磷脂在单分散胶体表面进行组装,制备了一种具有热磁双重响应性的新型载药微囊.通过透射电镜、激光共聚焦显微镜、zeta-电位分析仪、紫外分光光度计等对微囊结构及载药、释药性能进行了表征.实验结果表明:微囊的载药量最高可达到22.40%,且具有磁导向作用.微囊外层组装具有热敏性质的磷脂层能有效地克服壳聚糖/海藻酸钠微囊通透性大而导致在较低温(正常生理环境)的输送过程中药物泄漏问题,而在较高温条件下又可使药物迅速释放,从而实现药物的可控释放.     

应用于药物控释系统中的生物降解高分子材料

生物降解高分子材料具有良好的生物相容性和生物降解性而成为人们关注的药物控释材料。本文简要介绍了生物降解高分子材料的降解机理，综述了生物降解高分子材料的发展现状，展望了今后的发展方向。     

应用于药物传输系统的聚合物纳米粒

载药聚合物纳米粒具有良好的组织靶向性和缓控释性，本文简要介绍了聚合物纳米粒在药物传输系统中的特点，综合分析并讨论了纳米粒的制备技术及应用，展望了今后的研究方向。     

结肠靶向偶氮高分子的合成及其体外降解性能

以二环己基碳酰亚胺/N,N-二甲基氨基吡啶为偶联剂,将结肠前体药物5,5′-偶氮二水杨酸(奥沙拉秦)与生物相容的聚乙二醇缩聚,制备得到主链含偶氮键的聚乙二醇-奥沙拉秦(PEO-OLZ)缩聚物.研究表明,改变聚乙二醇链段的分子量,可以方便地调节偶氮缩聚合物的亲水性和生物降解性能.在动物盲肠液中所含的偶氮还原酶的作用下,PEO-OLZ缩聚物的偶氮键发生特异性降解,同时通过酯键的水解,释放出抗结肠炎药物5-氨基水杨酸.该类新型偶氮缩聚物可以作为结肠靶向聚合物前体药,亦可用作结肠定位控释的高分子载体.     

聚己内酯聚醚嵌段共聚物和共混物的表面性质对其药物释放行为的影响

聚己内酯聚醚嵌段共聚物和共混物的表面性质对其药物释放行为的影响王卫华，贝建中，王智峰，王身国（中国科学院化学研究所北京１０００８０）关键词聚己内酯聚醚嵌段共聚物，共混物，电子能谱，表面性质，药物释放行为聚己内醋（ＰＣＬ）具有优良的药物通透性和生物相容...     

SPECTRAL CHARACTERISTICS OF FREE AND LINKED PYRENE-TYPE CHROMOPHORES IN SOLUTION,POLYMER MATRICES,AND INTERPENETRATING NETWORKS

Monomers, 1-pyrenylmethyl methacrylate (PyMMA), 1-pyrenylbutyl methacrylate (PyBMA), 4-(1-pyrenyl)methoxymethyl styrene (PyMMS) and allyl-(1-pyrenylmehtyl) ether (PyMAE), with pyrene as chromophore, were prepared. Their spectral properties (absorption, emission and emission decay) in solution, and doped or bonded in polymer matrices and complex polymer systems as interpenetrating polymer networks (IPN), were investigated. Spectral properties of pyrene-containing monomers doped in polystyrene (PS), polymethylmethacrylate (PMMA), polyvinylchloride (PVC), polyethylene (PE) and grafted on PE as well as copolymerized in buthylmethacrylate-co-styrene copolymer (BMA-co-S) have been compared. Absorption and emission spectra of pyrene type probes in solution and in IPN matrices exhibit typical absorption of the pyrene moiety. For IPN with grafted probes on PE, the absorption is slightly shifted to red wavelength. For monomers, PyMMA, PyBMA and PyMAE grafted to PE, the shape of the emission spectrum depends on the wavelength of excitation. The ratio of intensity of the vibrational band, I₁/I₃, (I₁ peak at 377 nm and I₃ peak at 388 nm) has been a quite useful indicator of polarity of IPN. The relative quantum yields of fluorescence in IPN matrices are lower in comparison to polymer matrices of PE, PS, PMMA for all probes under study. The fluorescence life-times for bound and free probes have been in the range 100–200 ns, which is substiantialy shorter than for the parent pyrene chromophore under the same or similar condition. Grafted probes on PE alone, or as a part of IPN, exhibit substantially shorter life-time around 10 ns and decay is rather complex.     

浸润性梯度表面研究与应用

浸润性梯度表面是指表面浸润性随着表面位置的变化而连续变化的一种特殊梯度表面.在过去的20年间,由于浸润性梯度表面在智能涂料、微流体器件和液体自输送等方面具有广阔的应用前景,因此人们研发并制备了各种类型的浸润性梯度表面,总体而言,可分为三类:(1)化学组成类浸润性梯度表面;(2)表面形貌类浸润性梯度表面;(3)化学组成-表面形貌复合型浸润性梯度表面.重点介绍了这三大类浸润性梯度表面的分类与区别,以及近些年来这些新型浸润性梯度表面的主要制备方法,如扩散法、浸泡法、刻蚀与打印、机械拉伸法、半月板沉积法和温度梯度法等,并归纳总结了这些方法的各自优缺点.在目前的材料科学领域,虽然关于浸润性梯度的研究还属婴儿期.可是利用梯度表面研究生物蛋白或细胞吸附,液体自输送等,已经发展成为一门成熟的学科.最后综述了近期关于浸润性梯度表面在研究生物蛋白或细胞吸附,液体自输送等方面的应用进展,并展望了该课题的未来发展.     

环氧树脂在碳纤维表面的浸润行为

利用场发射环境扫描电境(FESEM)测定了室温下环氧树脂在单纤维表面的接触角,观测并计算了环氧树脂液滴在单根碳纤维表面的接触角随温度的变化,结果表明接触角随温度升高明显降低,说明升高温度有利于改善环氧树脂对碳纤维的浸润性能.用液滴形状分析仪(DSA)在垂直和平行于纤维排列方向上观测了不同温度下单向排列碳纤维集束表面环氧树脂的铺展过程,发现在不同方向上观测到的接触角差别较大,其中垂直于纤维排列方向上观测到的接触角随温度的变化与环氧树脂在单根碳纤维表面的接触角变化基本一致,说明环氧树脂在平行于纤维束方向的接触角真正代表其浸润性能.     

明胶凝胶表面润湿性的研究

本工作利用测定几种参照液体在明胶凝胶上的接触角,定量地估算了明胶凝胶的表面自由能。加入表面活性剂,尤其是非离子表面活性剂,能增加明胶凝胶的表面自由能(主要是其极性分量)并大大改善明胶凝胶的表面润湿性。在表面上分子的吸附与定向和明胶凝胶中非极性网状结构形成的基础上,解释了上述实验结果。     

负载铈（IV）的D412螯合树脂氟性能的研究

以D412氨基酸型螯合树脂为载体,负载Ce(IV)制得选择性吸附剂。探讨了该吸附剂对水中的F^-的静态和动态吸附性能,实验中对含氟液pH值、浓度、流量以及再生液种类和浓度对该吸附剂性能的影响进行了研究,并采用红外分析方法推测了吸附剂吸附F^-的机理。     

有机铝钛缩聚物的合成

三烷氧基铝与螯合剂反应的产物或用其他方法稳定的二烷氧基铝化合物与含活泼羟基或羧基的双官能基化合物通过缩聚反应可以制得含铝的聚合物。有机铝聚合物的缺点是易水解、分子量不高、在有机溶剂中溶解性较差。本文由乙酰乙酸乙酯基二异丙氧基铝与二乙酰乙酸乙酯基-二(羟乙氧基)乙氧基钛合成有机铝钛缩聚物,并对所得有机铝聚合物的结构及热稳定性进行了表征。     

漆酚钕高聚物的合成

研究采用漆酚与氯化钕合成制备漆酚钕螯合高聚物的方法和工艺条件；ＩＲ和ＭＳ测定表明该产物存在邻酚基上的Ｏ－Ｎｄ键．ＤＴＡ和ＴＧ分析结果表明它具有比生漆更高的热稳定性，热分解动力学属一级反应，平均表观活化能１．３５６×１０５Ｊ·ｍｏｌ－１，磁化率为８．６０×１０－６ｃ．ｇ．ｓ．有可能作为优良耐热性能的有机高分子磁性材料     

ASPECTS OF THERMODYNAMICS OF POLYMER MIXTURES

In this brief review article some aspects of the thermodynamics of polymer mixtures are discussed, mainly based on the author's research. The studies of poly (methyl methacrylate)/chlorinated polyethylene (CPE), poly (butyl acrylate)/CPE and CPE/CPE (different chlorine content) mixture verify the "dissimilarity" and "similarity" principles for predicting miscibility of polymer mixtures. The sign of heat of mixing of oligomeric analogues is not sufficient in predicting the miscibility. The Flory equation of state theory has been applied to simulate the phase boundaries of polymer mixtures. The empirical entropy parameter Q_(12) plays an important role in the calculation, this reduces the usefulness of the theory. With energy parameter X_(12)≠0 and Q_(12)≠0 the spinodals so calculated are reasonable compared to experiments. A hole model was suggested for the statistics of polymer mixtures. The new hole theory combines the features of both the Flory equation of state theory and the Sanchez lattice fluid theory and can be reduced to them under some conditions.     

纳米金掺杂中空微胶囊的制备与表征

将表面含有双键的二氧化硅微粒分散在纳米金和聚乙烯吡咯烷酮溶液中.在此溶液中以聚乙烯吡咯烷酮为模板聚合物进行丙烯酸的模板聚合,得到二氧化硅为核、聚丙烯酸/聚乙烯吡咯烷酮/纳米金为壳层的核壳结构微粒.用氢氟酸将二氧化硅微粒去除后,得到了纳米金粒子掺杂的微胶囊.分别用扫描电子显微镜和激光共聚焦显微镜表征了微胶囊在干态和湿态下的形貌.通过电子衍射和透射电子显微镜确证了纳米金粒子在微囊壁上的存在和分布.     

聚合物胶体的空间稳定机理

本文从热力学角度阐述了聚合物胶体的空间稳定机理和影响聚合物胶体稳定的各种因素。     

IN-SITU AFM OF POLYMER CRYSTALLIZATION

Atomic force microscopy images taken during the crystallization of polyethylene both from processed andquiescent melts are presented. Crystallization from processed melts provides further evidence of a region in front of agrowing lamella that is influenced by the crystallization process, but extending only 40 nm into the melt. High-resolutionimages of the growing crystal tip, taken during crystallization, show no direct evidence of the existence of intermediatephases. The growing tip is shown to be slightly rounded. In-filling crystallization, occurring after the initial flush of growth,is imaged in polyethylene for the first time, and shown to continue to a temperature 8℃ below the initial crystallizationtemperature.     

掺杂/脱掺杂诱导的聚苯胺织物浸润性开关

以三氟乙酸(TFA)作为掺杂剂,三氯化铁为氧化剂,采用原位化学氧化法制得了具有超疏水性能的聚苯胺/棉布复合导电织物(PANI/CCT),所得织物在外界酸度诱导下发生掺杂/脱掺杂反应而导致其由导电态向绝缘态的转变,从而实现超疏水到超亲水的可逆、快速变化.研究结果证实上述的超疏水/超亲水可逆的变化来自聚苯胺与纤维的微/纳米结构和TFA的低表面自由能的协同效应.     

煤裂解过程中负载铁化学形态的变化

应用ＥＸＡＦＳ、ＸＡＮＥＳ和ＸＲＤ方法研究了褐煤中负载铁在裂解过程中化学形态的变化规律。结果表明，在载ＦｅＣｌ３．６Ｈ２Ｏ煤中，铁与煤表面碳－氧官能团发生强烈的相互作用。随热处理温度的升高，铁化学形态以如下顺序递变：高分散Ｆｅ－Ｏ／Ｃ络合物，超细ＦｅＯＯＨ，晶态Ｆｅ３Ｏ４，晶还原态铁（α－Ｆｅ，（Ｆｅ，Ｃ））《