抗凝血生物材料*

本文对抗凝血材料的研究进展进行了综述,着重介绍了血栓形成及凝血机理、提高生物材料表面抗凝血性能的改性材料和改性技术、抗凝血材料的表征等几方面的内容;分析了当前抗凝血材料研究中存在的问题,并对今后从分子水平上设计新型抗凝血材料进行了展望。     

肝素杂化材料的制备及抗凝血性质的初步研究

以甲苯二异氰酸酯(TDI)中的-NCO基与纳米金属氧化物表面的羟基发生反应,得到改性纳米金属氧化物,并使其与肝素钠(Heparin)进行接枝反应生成肝素杂化材料,结合红外、热重、扫描电镜(SEM)等表征方法,确定纳米金属氧化物确实接枝到了肝素钠的表面。通过对体外凝血时间和复钙时间的测定,来初步研究肝素杂化材料的抗凝血性质。结果表明：肝素杂化材料的抗凝血时间和复钙时间均比肝素钠的要短,表明它的抗凝血性比肝素钠的抗凝血性要弱一些;但比纳米金属氧化物和空白组的抗凝血时间和复钙时间要长,说明肝素杂化材料的抗凝血性与其相比则有明显的提高。     

材料表面性质调控细胞黏附

生物医用材料旨在通过调控材料和细胞之间的相互作用来实现组织的再生和修复。黏附过程直接决定了细胞是否能够充分发挥生物学性能,因此通过对材料表面的物理和化学改性来调控细胞黏附,对于生物材料具有至关重要的意义,也是非常活跃的研究热点。材料表面物理改性通常通过对包括表面粗糙度、形貌、模量和多孔结构等物理性质的调控,为细胞构建适合黏附的材料表面。而化学改性则借助于表面电荷及亲疏水性调控、促黏分子修饰等化学手段来提高材料表面与细胞间的相互作用力,进而促进细胞黏附。近年来,材料表面调控细胞黏附的研究取得了许多新的突破性进展。例如在传统的促黏分子表面修饰之外,人们逐步发现对促黏分子序构的精准调控也可以有效地提高材料表面的促黏性能。而刺激响应性表面则可以根据外界信号的刺激,使得材料表面在促黏和抗黏之间实现智能的转换。本文从物理改性、化学修饰、刺激响应性表面构建等角度出发,全面总结和讨论了材料表面性质对细胞黏附的调控作用,梳理了材料表面的设计思路,多种材料表面的修饰改性方法等最新进展,并展望了未来材料表面对细胞黏附的调控思路。     

高分子生物材料分子工程研究进展（上）

分子工程研究是生物材料发展的根本途径和必由之路。本文论述了近４０多年来高分子材料分子工程的研究主要进展，其中包括材料的抗凝血性、的组织相容性、材料表面的生物功能化和生物智能化、体内稳定高分子、体内可吸收高分子以及药物的控制释放。     

负载壳聚糖及其衍生物的材料表面血液相容性研究进展

壳聚糖及其衍生物具有多种生物活性,基于壳聚糖及其衍生物的材料表面改性是获取各种生物活性表面的重要手段,在生物材料领域显示出广阔的应用前景。为了获得血液相容性良好的壳聚糖改性生物材料表面,可通过引入具备抗凝活性的壳聚糖衍生物或壳聚糖/抗凝剂复合物来抑制壳聚糖固有的促凝作用。本文综述了负载有壳聚糖或其衍生物的材料表面的血液相容性改性方法方面的进展,并根据表面改性方法的不同按照物理改性和化学改性分别对其进行了阐述。     

抗菌生物材料的研究进展

生物材料的感染限制了生物材料的进一步应用.细菌在材料表面粘附、生长成细菌生物膜是生物材料相关感染难治的根本原因.因此,最有效的解决方法是防止细菌生物膜的形成.本文对目前抗菌生物材料的研究现状进行综述,提出目前防止细菌生物膜生成的方法主要有三种:抗细菌粘附的方法;杀菌的方法及二者相结合的方法.在设计抗粘附生物材料时,除了考虑材料表面的化学结构外,也要考虑材料的表面拓扑结构及材料的本体性能对细菌粘附的影响;在设计杀菌的生物材料时,不但要考虑杀菌性能,也要考虑杀菌剂对材料血液相容性的影响.总的来说,抗粘附的方法及杀菌相结合(多重抗菌)的方法是可望解决生物材料感染的一条新方法.     

聚多巴胺在生物材料表面改性中的应用

海洋生物贻贝通过其足腺分泌的具有超强黏附性能的蛋白,可在海水等潮湿环境中牢固黏附在各种材料的表面。受此黏附蛋白的启发,研究发现聚多巴胺(PDA)具有类似于贻贝黏附蛋白的结构和超强黏附性能。在碱性条件下,PDA可在各种材料的表面迅速成膜,其中含有大量亲水的羟基和氨基官能团,可提高材料表面的亲水性和化学多功能性;PDA可作为中间层,在基底材料表面强力结合功能分子。由于PDA的形成过程简单且不需要有机溶剂,近年来常被应用于材料的表面改性。此外,由于PDA可促进细胞的黏附,具有良好的生物相容性,在生物材料表面改性中也有较多的应用。本文将综述PDA的黏附机理及其在生物材料表面改性中的应用,并提出PDA在生物材料表面改性应用中的展望及研究过程中存在的问题,为PDA在生物材料和组织工程中的应用提供参考。     

纳米Eu2O3/硫酸酯化壳聚糖杂化材料的制备及其抗凝血性能研究

利用表面接枝的方法制备了纳米Eu2 O3/硫酸酯化壳聚糖杂化材料,并用IR,TG和SEM等方法对产物进行了表征,结果表明硫酸酯化壳聚糖接枝在了经过活化后的纳米氧化物表面,细胞毒性实验证明材料具有较低的细胞毒性和较好的细胞相容性.抗凝血实验说明材料具有良好的抗凝血性能.表面接枝方法提高了壳聚糖类化合物的抗凝作用,弥补了比...     

甲壳素的酰基化及其有生物材料上的应用

介绍了甲壳素及其衍生物的酰基化反应、产物的制备方法、酰化产物的性能及其用于生物医用材料上的最新进展。甲壳素及其衍生物的酰基化改性是一种很有价值的化学改性途径，不仅可改善酰化产物在有机溶剂中的溶解性或水溶性，而且产物作为生物材料具有许多独特的用途。     

甲壳素的酰基化及其在生物材料上的应用

介绍了甲壳素及其衍生物的酰基化反应、产物的制备方法、酰化产物的性能及其用于生物医用材料上的最新进展。甲壳素及其衍生物的酰基化改性是一种很有价值的化学改性途径，不仅可改善酰化产物在有机溶剂中的溶解性或水溶性，，而且产物作为生物材料具有许多独特的用途。     

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%).     

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 pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles by Curtius reaction in Morita-Baylis-Hillman derivatives

Synthesis of substituted pyrrolo[1,2-a]pyrazines and pyrazino[1,2-a]indoles from the Morita-Baylis-Hillman derivatives of acrylates via saponification followed by Curtius reaction is described.     

正丁胺对激光染料荧光谱影响的研究

用正丁胺作为碳源,采用射频辉光放电制备碳膜,选用激光染料R6G和聚乙二醇混合液作为蒸气源,采用单源热蒸发,在蒸发室与染料同时沉积得到混合膜,用拉曼光谱和红外光谱分析了碳膜的结构和键合方式,分析表明:碳膜中存在胺基团和氢原子.混合膜的荧光谱测量结果表明,认为正丁胺对染料荧光谱的影响是因为胺基和氢原子的存在.     

Cu0-catalysed 1,3-dipolar cycloadditions of α-amino acid derived N,N-cyclic azomethine imines to ynones

A series of 20 CuAIAC reactions between eight 4-acylamino substituted pyrazolidine-3-one-1-azomethine imines and four terminal ynones were performed using Cu⁰ as catalyst. The corresponding fluorescent cycloadducts were obtained in very high yields upon simple workup. Thus, Cu-metal turned out to be a better catalyst than Cu^I in terms of yield and ease of isolation. Availability of azomethine imines, mild reaction conditions, and simple workup enable a “click” access to libraries of densely substituted 2,3-dihydro-1H,5H-pyrazolo[1,2-a]pyrazol-1-ones. Reactivity of differently substituted dipoles was evaluated experimentally and by quantum chemical methods (DFT).     

Synthesis and antioxidative/anti-inflammatory activity of novel fullerene–polyamine conjugates

(E)-4-(Fullerenopyrrolidin-1-yl)-3-methylbut-2-enoic acid and its corresponding succinimidyl ester, readily obtained through Prato-type modification of C₆₀, were used for the selective N-acylation of polyamines. The thus obtained conjugates were evaluated for their antioxidative and anti-inflammatory activity and their cytotoxicity was determined. Members of this family of compounds showed interesting anti-lipid peroxidation, anti-lipoxygenase and anti-inflammatory activity and comparable cytocompatibility to spermidine.