基于超大孔聚合物微球的混合色谱模式层析介质的制备

以甲基丙烯酸缩水甘油酯与乙二醇二甲基丙烯酸酯共聚的超大孔聚合物微球为基质,采用聚乙烯亚胺和丁基缩水甘油醚先后衍生微球的表面,制备成兼具阴离子交换与疏水相互作用的混合色谱模式层析介质。考察离子交换基团、疏水配基密度对蛋白载量、回收率的影响,结果表明,在离子交换容量0.2~0.5 mol/mL范围内,随着介质离子交换容量的增大,蛋白载量及回收率均呈增加趋势,蛋白载量最高值达40 mg/mL,回收率大于90%。当疏水配基的密度大于0.03 mol/mL时,介质开始表现疏水相互作用。此超大孔混合模式色谱介质在大于2000 cm/h 的流速下依然能保持低于2 MPa 的柱背压,同时在高流速下(2880 cm/h)纯化人血清中的抗体应用中表现良好的分辨率。此介质在高通量分离纯化应用方面具有巨大潜力。     

致孔剂溶解度参数对大孔层析介质的结构影响研究

分别以甲基丙烯酸缩水甘油醚酯和乙二醇二甲基丙烯酸酯为功能单体和交联剂,采用悬浮聚合方法制备了大孔聚合物微球。考察了致孔剂的组成及用量对微球的孔径、比表面积的影响,其中随着致孔剂中的良溶剂(二氯甲烷δ=9.7(cal/cm~3)~(1/2)和不良溶剂(正辛醇δ=10.3(cal/cm~3)~(1/2)的比例变化,致孔剂体系溶解度参数可调范围为9.89~10.09(cal/cm~3)~(1/2),随着致孔剂与聚合物之间溶解度差值的增加,微球的孔径随之增大而比表面积呈下降趋势。将此类微球偶联聚乙烯亚胺衍生为阴离子交换层析介质,以前沿分析法比较了不同孔径的微球的传质性能,其中孔径为257 nm的介质仍能保持较高的动态蛋白载量(45.1 mg/m L),表明此类大孔介质在高通量分离纯化应用方面具有很大潜力。     

一种温敏型超大孔生物分离介质的制备及表征

采用改性琼脂糖对超大孔聚苯乙烯微球进行亲水化修饰(Agap-PS),通过酰基化反应在微球表面引入溴乙酰基(Agap-PS-Br),然后利用原子转移自由基聚合(ATRP)反应在Agap-PS-Br表面接枝温敏聚合物刷,得到一种温敏型超大孔生物分离介质(Agap-PS-PNIPAM).考察了配体、催化剂、溶剂和温度对N-异丙基丙烯酰胺ATRP反应的影响,在优化条件下PNIPAM的接枝量达到了15.07 mg/m2.采用红外光谱(FTIR)、扫描电镜(SEM)、压汞分析、激光共聚焦和蛋白吸附等手段对温敏型超大孔生物分离介质进行一系列表征,结果表明接枝温敏聚合物刷后Agap-PS-PNIPAM具有良好的温敏性,没有堵塞微球的超大孔,微球对蛋白的非特异性吸附大大降低.由于温敏聚合物刷发生了从亲水到疏水构象的转变,40℃时Agap-PS-PNIPAM对蛋白的吸附量是25℃时的2.69倍.压力流速实验表明Agap-PS-PNIPAM柱具有背压低、渗透性和机械稳定性好的优点,同样地由于PNIPAM链在40℃时收缩,此时Agap-PS-PNIPAM柱的床层渗透系数比25℃时提高了15.7％.     

肽配基纳米亲和载体定向固定化抗体

抗体经常被固定在某一固相载体表面用于免疫检测分析,但通常得到的是随机固定化的抗体,因而会影响抗体的活性。本文开发了一种新型的亲和载体用于抗体的定向固定化。即将与抗体IgG的Fc片段具有亲和作用的肽配基偶联于pGMA纳米球上,制备亲和载体用于吸附抗体实现抗体的定向固定化。首先利用乳液聚合法制备了粒径为110nm的pGMA纳米球,再以EDMA为交联剂并且在纳米球表面氨基化,最后将与抗体IgG的Fc片段具有亲和作用的肽配基HWRGWV偶联于纳米球表面,制备得到肽配基纳米球亲和载体。然后,考察了亲和载体对猪IgG的吸附行为。进一步,利用等温滴定微量量热仪研究了该纳米球亲和载体与IgG之间的相互作用热力学。结果表明,肽配基亲和载体对IgG的特异性吸附作用明显高于肽配基修饰前的载体。亲和载体与IgG的亲和作用主要贡献是疏水相互作用;而IgG与氨化纳米球载体的吸附作用则主要通过静电作用和氢键作用。所制得的纳米球亲和载体可用于进一步开发高效率、高灵敏度的临床免疫检测方法。     

大孔聚合物层析介质孔结构对蛋白载量的影响

分别以甲基丙烯酸缩水甘油酯和乙二醇二甲基丙烯酸酯作为功能单体和交联剂,采用悬浮聚合方法制备了大孔聚合物微球.考察了致孔剂组成对微球的孔径、比表面积的影响,并用聚乙烯亚胺将微球衍生为阴离子交换层析介质,考察了微球结构与蛋白载量之间的关系.结果表明,微球孔径尺寸随着致孔剂中不良溶剂用量[V(良溶剂)/V(不良溶剂)=1∶1～1∶3. 5]的增加而增大,而比表面积则呈相反趋势.离子交换容量(0. 11～0. 27 mmol/m L)与比表面积(4～38 m2/g)呈正相关,对应的蛋白静态结合载量亦呈正比关系.在所考察的孔径范围(301～1524 nm)内,蛋白动态结合载量先减少后保持稳定,即当孔径超过410 nm后,蛋白动态载量值保持在13 mg/m L不变,表明介质孔径超过此数值后蛋白载量不再受介质的比表面积影响.此外,以乙肝病毒表面抗原分子(HBs Ag,22 nm)为探针分子,利用激光共聚焦显微镜观察了该分子在微球内部的分布,结果表明,在该孔径考察范围内,HBs Ag均能完全扩散至微球内部.     

接枝多胺聚合物制备大孔阴离子交换色谱介质及其蛋白吸附行为评价

以环氧活化聚甲基丙烯酸酯大孔微球(FastSep-epoxy)为基质,通过接枝聚(烯丙基胺)(PAA)制备了大孔阴离子交换色谱介质(FastSep-PAA)。考察了介质的合成条件对离子交换容量(IC)及蛋白结合容量的影响,发现IC随PAA浓度、反应时间和溶液pH的增加均表现为增长趋势;同时结合蛋白吸附容量的变化选择了最优合成条件。通过扫描电子显微镜观察介质的表面形貌,发现其孔隙连通性较好,且接枝前后介质孔道结构无明显变化,PAA配基密度对介质结构无明显影响。此外,通过压汞法和氮气吸附法测定接枝前后不同介质的孔径尺寸和孔径分布情况,并考察该类介质的孔径与蛋白吸附行为的关系,发现其蛋白结合容量未出现随介质孔径尺寸增加而显著下降的现象,且孔径尺寸增加更有利于蛋白在介质内部传质。在126 cm/h的流速下FastSep-PAA介质的原始孔径(即FastSep-epoxy的孔径)为400 nm时的蛋白动态结合容量(DBC)最高(70.3 g/L),该孔径下介质比表面积大,蛋白可吸附位点较多;原始孔径为700 nm及以下的介质蛋白DBC均随流速增加而均有一定下降;原始孔径为1 000 nm的介质蛋...     

双孔色谱介质的制备和质粒DNA快速色谱纯化

以甲基丙烯酸缩水甘油酯为单体,二甲基丙烯酸乙二酯为交联剂,环己醇与十二醇为有机致孔剂,200 g/L的碳酸钙悬浮液为内水相(超孔致孔剂),用二次乳化法制备了(W/O)/W乳液,通过紫外光引发悬浮聚合生成两类孔型高分子微球(DEA-B).DEA-B孔径为双峰分布,范围分别为50~200 nm和500~5000 nm.其体积平均粒径、湿密度与不含超孔的微孔介质(DEA-M)接近.在流速为0.5 mL/min(150 cm/h)及相同的洗脱条件下,比较了所制备的微孔色谱介质填充的色谱柱与双孔色谱介质填充的色谱柱对5.4 kb质粒DNA的分离效果.结果表明,仅双孔介质色谱柱可以纯化质粒DNA,并且可以在1500 cm/h的高流速下得到色谱纯的质粒DNA,证明该双孔色谱介质可以用于质粒DNA的高速分离.     

碳纳米管复合微球修饰L-色氨酸及其对LDL的吸附性能

本文以多孔碳纳米管/活性炭复合微球为载体,以L-色氨酸为配基,采用环氧氯丙烷偶联法,制得修饰L-色氨酸的碳纳米管/活性炭复合微球(L-CNTs/AC)。采用扫描电镜、氮气吸附、傅立叶红外光谱、热分析、X射线光电子能谱等对复合微球进行表征;通过体外静态吸附法对其低密度脂蛋白(LDL)吸附能力进行初步研究。结果表明:环氧氯丙烷偶联法可接枝上L-色氨酸。复合微球中碳纳米管加入量越多,对LDL的吸附能力越强;当碳纳米管加入量为45wt%时,对LDL的吸附量达4.623 mg·g-1,是未添加碳纳米管的2.3倍多。这是因为碳纳米管不仅可促进复合微球中20~100 nm孔的形成,而且还可促进复合微球配基修饰量的增多,从而大大增强了复合微球对LDL的吸附能力。此复合微球可望开发成一种新型的血液灌流LDL吸附剂。     

混合模式色谱配基密度对抗体吸附分离性能的影响

作为蛋白A色谱的重要替代技术,混合模式色谱(mixed-mode chromatography,MMC)具有稳定、廉价和选择性好等优势。本文考察了以Sepharose Fast Flow为基质、4-(咪唑-1-基)苯胺(AN)为配基的新型色谱介质AN SepFF中配基密度对抗体吸附行为和分离性能的影响。研究结果表明,AN SepFF色谱介质在抗体吸附中具有21.2mmol/L的临界配基密度。在临界配基密度以上,抗体在色谱介质上具有较高的吸附容量和很低的解离常数并展现了相当程度的盐耐受性。动态吸附结果进一步表明,抗体的色谱介质中具有与商品化介质相当的动态吸附容量。抗体纯化的结果也表明,在临界配基浓度以上AN SepFF色谱表现出较好的纯化抗体的能力,其抗体产品纯度高于目前商品化的色谱介质;配基密度为55mmol/L时,AN SepFF色谱纯化抗体的收率达到91.9%。由此,AN SepFF色谱介质展现了巨大的应用前景。     

高分子微球偶联固定卡托普利药物分子的研究

采用无皂乳液聚合法制得聚苯乙烯-甲基丙烯酸缩水甘油酯(PSG)乳液微球,然后在微球表面嫁接空间臂分子1,6-己二胺,得到表面含氨基的PSGN微球,接着借助EDC/NHS催化作用将药物分子卡托普利化学偶联到PSGN微球表面,制成固定卡托普利的亲和PSG微球。实验着重考察了PSGN微球偶联固定卡托普利反应过程中催化剂比例和用量、pH值、反应温度和时间等的影响规律。结果表明,在25℃,pH为4.0,m(NHS)∶m(EDC)=1∶2,EDC的浓度为4mg/mL的条件下,卡托普利偶联到微球表面的效果较好。     

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.