超疏水性表面的制备及应用进展

近年来,受荷叶、水黾腿、壁虎脚等天然超疏水生物表面特性的启发,研究者们进行了大量仿生超疏水表面材料的制备及应用研究。超疏水性表面因其特殊的微纳分层结构,具有自清洁、防覆冰、防腐蚀、减阻等优异性能。本文阐述了表面润湿、疏水的基本机理,以及超疏水表面研究的理论基础,对超疏水表面制备的最新研究进展进行了综述,并揭示了研究中存在的问题。最后,介绍了超疏水表面在涂料、织物、防腐、抗菌及防雾等领域中的应用,展望了其未来的研究方向和前景。     

超疏水表面的研究进展

表面的浸润性是决定材料应用的一个重要性质,许多物理化学过程,如吸附、润滑、黏合、分散和摩擦等均与表面的浸润性密切相关.近年来,由于超疏水表面在自清洁表面、微流体系统和生物相容性等方面的潜在应用,有关超疏水表面的研究引起了极大的关注.本文综述了超疏水表面研究的新进展:简单介绍了表面浸润性的表征手段和影响因素,归纳了超疏水表面的制备方法和相关的理论分析,对超疏水表面研究的发展进行了展望.     

微通道蛋白质吸附的流动电势表征

蛋白质在固体表面的吸附与许多生命现象和生物应用相关,比如血液凝结、细胞粘附及材料的生物相容性等~([1]),也是化学、生物、医学、材料等多种学科都密切关注的问题~([2]),相应研究有很大的科学价值和应用前景.     

仿生超疏水性表面的研究进展*

仿生超疏水性表面的研究是化学模拟生物体系研究中的一个新领域。荷叶等植物叶面的超疏水现象为我们在不同基底上制备仿生超疏水性表面提供了实践基础。本文给出荷叶等三种植物叶面的超疏水性和微观结构，阐述了仿生超疏水性表面的研究进展。     

环糊精超分子聚合物在药物/基因递送载体领域的研究进展

超分子聚合物通常以非共价键作为构筑驱动力,其结构具有动态可逆的特点,在新型响应性聚合物材料中具有突出优势。环糊精可通过主客体识别作用与客体分子如二茂铁、偶氮苯、金刚烷、苯环等形成包合,以此构筑的超分子组装体展现出丰富的自组装-解组装特性、刺激响应性、较低的细胞毒性和较好的生物相容性,有望在药物/基因载体领域得到应用。本文从环糊精超分子聚合物的生物医用出发,着重对近年来环糊精超分子聚合物载体在药物控制释放、基因转染以及药物/基因共递送三方面的研究进展进行了总结和评述,并在此基础上展望了环糊精超分子聚合物的研究方向和发展趋势。     

表面改性聚丙烯的血液相容性研究进展

聚丙烯具有价格低廉、无毒、易于加工等优点,使其在许多领域得到广泛的应用。但是聚丙烯自身有较强的疏水性,与血液相接触时,血浆蛋白会在材料表面大量吸附,诱发血小板的粘附和聚集,从而造成凝血和溶血的发生。在生物医用材料的应用过程中,血液相容性是限制材料能否长期应用的关键因素。本文综述了表面改性法提高聚丙烯血液相容性的研究现状、表面改性方法和常用的大分子单体,并分析了当前聚丙烯表面改性研究存在的问题,展望了具有良好血液相容性聚丙烯的发展前景。     

微纳米多孔不锈钢表面高效吸附活性生物大分子

不锈钢(AISI 316L)是目前在医药器械中应用最为广泛的商业化材料. 下一代的不锈钢智能材料将特殊功能的生物活性分子(或纳米粒子)修饰在金属表面以模拟组织功能、提高生物/细胞相容性, 这是目前材料科学研究的热点领域之一. 本文研究了具有微纳米多孔表面结构的316L 不锈钢对抗体和生物酶分子的吸附作用,并与这些生物分子在光滑表面以及镀金表面的吸附进行了比较. 研究发现不锈钢可通过简单的电化学腐蚀方法在表面产生微纳米多孔结构. 微纳米孔不锈钢表面可稳定地吸附抗体或辣根过氧化物酶分子, 其吸附量与喷镀金表面相当或更好. 用表面活性剂(10%牛血清白蛋白(BSA)或0.2% Tween-20)洗涤不能除去吸附的蛋白.用5% Tween-20 预处理金属表面, 则可减少一半的抗体吸附量; 但表面活性剂预处理对辣根过氧化物酶的吸附没有影响. 吸附蛋白质后的金属表面湿润度大大增加; 蛋白质修饰的微纳米孔不锈钢表面表现出了很好的亲水性(水接触角小于50°), 指示了很好的生物相容性. 而金属表面的湿润度则主要取决于蛋白质物种, 并与蛋白质的吸附量正相关. 吸附于不锈钢微纳米孔表面的抗体仍保持了良好的生物活性; 用此种方式制备的抗CD34抗体修饰的不锈钢血管支架可以高密度并高选择性地吸附其目标细胞(如KG-1细胞). 本文工作为未来制备新型的无高聚物涂层的不锈钢智能医学生物材料提供了基础.     

耗散型石英晶体微天平在生物医用高分子材料中的应用

石英晶体微天平(QCM)是一种基于石英晶体压电效应的分析检测技术,可实时在线提供石英晶体表面吸附层质量、厚度、粘弹性等信息,由此获得表面分子相互作用关系。 耗散型石英晶体微天平(QCM-D)因其独特的对粘弹性的解析,使其在高分子材料中的应用迅速发展,尤其是生物医用高分子材料领域,已用来评价生物医用高分子材料的表界面相互作用,力学和生物相容性等。 本文简单介绍了耗散型石英晶体微天平的基本原理及理论模型,重点综述了近几年QCM-D在高分子链构象、蛋白质吸附、生物大分子相互作用、药物释放以及水凝胶中的应用,并且展望了QCM-D的未来发展趋势。     

微图案化钙磷盐膜层的电化学构筑及其生物性能

基于表面分子自组装和光催化转印技术,在TiO2膜层表面获得超亲/超疏水阵列微图案模板,结合电化学沉积技术,成功制备了微图案化钙磷盐膜(CaP)层.扫描电子显微镜(SEM)和电子探针分析(EPMA)结果表明,通过超亲/超疏水阵列微图案模板可构筑高空间分辨的微图案化钙磷盐膜层.微图案化钙磷盐膜层的体外MG-63细胞培养证实,细胞对钙磷盐膜层微单元有强烈的选择性粘附作用,从而可望控制细胞在微单元中的贴壁生长,实现高通量评价细胞行为.     

聚醚聚酯嵌段共聚物共混物表面组成的ESCA研究

<正> 关于生物医用材料的微多相分离结构和适宜的亲、疏水性同它血液相容性间关系的研究已有不少文献报道。由于材料在使用时真正同血液相接触的只是材料的表面部分,因此材料的表面组成、结构和性质对它的血液相容性就具有更为直接的关系。对聚醚     

A carbanion induced synthesis of highly congested pyrazole and imidazole containing heterocycles

An efficient approach to the synthesis of highly congested di, penta and hexacyclic pyrazoles as well as imidazole fragment containing novel heterocyclic molecule has been developed through a carbanion induced transformation of suitably functionalized 2H-pyran-2-ones, benzo[h]chromene and thiochromeno[4,3-b]pyrans. Due to the presence of fluorescence, we report their prime application metal sensor as off/on switching in ferric ions.     

α-Amino acid derived enaminones and their application in the synthesis of N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates and other heterocycles

A new and simple synthesis of novel N-protected methyl 5-substituted-4-hydroxypyrrole-3-carboxylates, which exist in equilibrium with their 4-oxo tautomers, has been developed in two steps starting from N-protected α-amino acids. The key intermediates are enaminones, which can also be isolated, characterized, and used for the construction of other functionalized heterocycles, before they spontaneously decompose to pyrrole products. 4-Hydroxypyrroles are prone to partial aerial oxidation but can be efficiently alkylated or reduced to stable polysubstituted pyrrolidine derivatives.     

Specific intramolecular aromatic CH insertion of diazosulfonamides

The chemoselectivity in the intramolecular CH insertion of various diazosulfonamides has been experimentally studied. The results reveal that the aliphatic 1,4-, 1,5-, or 1,6-C(sp³)?H insertions of diazosulfonamides are not accessible, while the aromatic 1,5-C(sp²)?H insertion can be realized specifically by adjusting the diazo-adjacent group. In addition, the general chemoselectivities in the intramolecular CH insertions of diazosulfonyl compounds are summarized. Generally, diazosulfones undergo both aromatic 1,5-C(sp²)?H and aliphatic 1,5- and 1,6-C(sp³)?H insertions, while diazosulfonates undergo aliphatic 1,5- and 1,6-C(sp³)?H insertions. However, diazosulfonamides only undergo aromatic 1,5-C(sp²)?H insertion.     

N-Heterocyclic carbene-palladacyclic complexes: synthesis,characterization and their applications in the C-N coupling and α-arylation of ketones using aryl chlorides

N-Heterocyclic carbene-palladacyclic complexes 3 were successfully achieved in a one-pot procedure under mild conditions. The structure of 3a was unambiguously confirmed by X-ray single crystal diffraction and it was an active catalyst in the Buchwald-Hartwig amination and α-arylation of ketones even at very low catalyst loadings (0.01?mol%).     

Selective synthesis of 4,5-dihydroimidazo- and imidazo[1,5-a]quinoxalines via modified Pictet–Spengler reaction

An efficient tandem approach for the selective synthesis of 4,5-dihydroimidazo[1,5-a]quinoxalines 6a–g and imidazo[1,5-a]quinoxalines 7a–h by the reaction of 2-imidazolyl anilines 4a–c with aryl aldehydes 5a–k under mild reaction conditions is described. Introduction of electron releasing alkyl groups in substrates 4a–b was found to be instrumental for the success of the reaction.     

Understanding the Diels-Alder reactivity of 1,2-azaborine analogues

The Diels-Alder reactivity of 1,2-heteroborines (H₄C₄B(H)X, X?=?NH, PH, AsH; O, S, Se) has been computationally explored by means of Density Functional Theory (DFT) calculations. The influence of the HB?=?X fragment on the reactivity of the system has been quantitatively analyzed in detail by means of the so-called Activation Strain Model (ASM) of reactivity. It is found that the interaction between these species and the dienophile is significantly stronger than that computed for their all-carbon isoelectronic counterpart, benzene. In addition, the strain energy plays a key role in the observed reactivity trends. The role of the aromaticity strength of these heteroarenes on the reactivity is also assessed.     

Synthesis of N-substituted carbazolones from α-iodo enaminones via Pd(0)-catalyzed intramolecular coupling under microwave irradiation

A variety of N-aryl and N-alkyl carbazolones were conveniently achieved in good to high yields via Pd₂(dba)₃-mediated intramolecular coupling of N-substituted α-iodo enaminones under microwave irradiation. The Pd(0)-catalyzed cyclization was found to proceed favorably with the more electron-deficient phenyl ring during the reactions involving unsymmetrical N,N-diaryl α-iodo enaminones. This unique property enables the construction of carbazolone skeleton containing nitro substituted benzenoid ring.     

Iodine-mediated oxidative Pictet-Spengler reaction using terminal alkyne as the 2-oxoaldehyde surrogate for the synthesis of 1-aroyl-β-carbolines and fused-nitrogen heterocycles

An efficient iodine-mediated oxidative Pictet-Spengler reaction in dimethyl sulphoxide (DMSO) using terminal alkynes as the 2-oxoaldehyde surrogate for the synthesis of aryl (9H-pyrido[3,4-b]indol-1-yl)methanones is described. The scope of the protocol includes the total synthesis of Fascaplysin, Eudistomins Y₁ and Y₂. The methodology is extended for preparing pyrrolo[1,2-a]-quinoxaline and indolo[1,5-a]quinoxaline derivatives. The utility of 1-aroyl-β-carbolines was demonstrated by performing palladium-catalyzed β-carboline directed ortho-C(sp2)-H functionalization of the phenyl ring with thiomethyl (SMe) group using DMSO as source and for accessing 4-aryl-canthin-6-ones.     

Facile synthesis of bicyclic 1-arylpyrazol-5-ones

In this Letter, we described a facile method for constructing fused bicyclic 1-arylpyrazol-5-one ring system. We employed various methylene-containing carboxylic acids as the substrates and proved that the pyrazolone ring closure requires activated methylene group in intermediate II. Accordingly, a series of structurally diversified, fused bicyclic 1-arylpyrazol-5-ones was prepared in moderate to high yields using the requisite substrates.     

Synthesis of substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles by intramolecular nitrilimine cycloaddition

Both substituted 2,4,5,6-tetrahydrocyclopenta[c]pyrazoles and 2,4,5,6-tetrahydropyrrolo[3,4-c]pyrazoles have been synthesized by the 3+2 intramolecular dipolar cycloaddition of nitrilimines to alkynes. This cyclization has been extended to more versatile 3-bromo derivatives by the use of alkynylbromides as dipolarophiles.