基于蛋白A定向固定的Love波免疫传感技术研究

报道了一种基于蛋白A固定技术的新型Love波免疫传感器,可用于检测B型葡萄球菌肠毒素(SEB).本传感器由压电石英基片、叉指换能器和SiO2声波导层构成.为提高传感器对SEB分子的响应能力和检测灵敏度,设计了抗体分子的蛋白A定向固定路线,通过APTES和戊二醛层交联蛋白A,随即用100mmol/LNaBH4还原蛋白A与戊二醛层之间形成的Schiff's base结构,实现抗体分子在Love波器件表面高效率的定向固定.该固定化方案使传感器的再生能力和检测灵敏度都得到显著提高,对10 mg/L SEB进行连续5次检测后,其响应能力没有明显下降;而对SEB的浓度检出限度达到了10μg/L.原子力显微镜对传感器表面形态的成像结果表明,与戊二醛共价交联法相比,蛋白A结合法使抗体分子探针在传感器表面拥有更高的覆盖度和活性,对SEB具有更强的结合能力.     

蛋白A定向固定抗体的纤维蛋白压电免疫传感器的研究

将9MHz双面镀金石英晶体浸入蛋白A溶液中,在晶体电极表面形成一层均匀的蛋白A薄层,用于定向固定人体纤维蛋白抗体.在蛋白A层上形成一层有序致密的自组装抗体分子膜,研制成一种新型的用于人体纤维蛋白检测的压电免疫传感器.比较了3种固定抗体方法的效果,从传感器的灵敏度、稳定性、重现性等考虑,蛋白A吸附法优于聚乙烯亚胺及牛血清白蛋白固定抗体的方法.研究了蛋白A浓度、抗体效价以及抗原抗体反应时间等对传感器灵敏度的影响,考察了电极的选择性和再生能力.纤维蛋白在1×10^-4～1×10^-2g/L浓度范围内有良好响应.     

一种新的压电免疫传感器中生物分子固定化方法的研究

生物分子固定化或传感界面设计技术是研制压电免疫传感器的关键之一。本文 结合自组装单分子膜（SAMs）和聚电解质静电吸附组装技术，提出了一种新的压电 免疫传感器中生物分子固定化方法，研制成一种检测补体C_3的压电免疫传感器。 先在石英晶振的金电极表面组装一层胱胺SAMs，再在膜上组装带相反电荷的聚苯磺 酸钠（PSS）单层膜，通过静电吸附作用固定抗体（抗原），实现对相应抗原（抗 体）的检测。利用扫描电镜技术，从形态上考察了晶振组装胱氨SAMs与PSS及固定 补体C_3抗体后的表面形貌。研究了抗体的固定化条件，探讨了传感器采用这种固 定化方法的响应与再生性能，并与戊二醛键合固定法进行比较。结果表明，这种固 定化方法不仅对蛋白质类生物分子的固定化具有普适性，而且对所固定的生物分子 的活性影响小，传感器的响应的频移值大，灵敏度高，选择性和再生性能均较好。     

Love波免疫传感器在免疫分析中的研究

Love波免疫传感器是一种以免疫反应为识别方式的新型声表面波传感器。与其它压电声波免疫传感技术相比,水平剪切型表面波、高的压电晶体基频以及声波导层的存在使Love波免疫传感器在可用于气液两相检测的同时具有更高的灵敏度,从而可以成为免疫分析中的一种重要的工具。本文分别从Love波传感器的构造、原理、发展现状和以抗体作为探针在传感器表面的固定化方法两方面综述了Love波免疫传感器的研究进展。     

基于胱氨自组装膜的压电免疫传感器检测抗凝血酶Ⅲ

提出了一种基于胱氨自组装膜和采用聚电解质吸附法固定活性物质的压电免疫传感器，用于检测人血浆中抗凝血酶Ⅲ（AT－Ⅲ）。先在压电石英晶振的金电极表面自组装一层带疏基的胱氨单分子膜，再在膜上组装一层聚电解质褐藻酸钠（AAS），通过静电吸附作用，将AT－Ⅲ抗体固定于石英晶体表面，在含有3.5%聚乙二醇（PEG）的缓冲溶液中检测AT－Ⅲ。比较了传感器分别采用AAS吸附法和戊二醛键合法固定AT－Ⅲ抗体的响应性能，发现前者固定的抗体的活性较高，反应响应的频移值较大，检测的线性范围也较宽。实验采用PEG作免疫反应的促进剂，进一步改善了传感器的检测灵敏度和检测限。采用Piranha试剂作洗脱液可实现传感器的反复再生。干扰与回收率实验结果表明，该传感系统可用于人血浆中AT－Ⅲ的临床检测。     

纳米金自组装膜的IgM压电免疫传感器的研究

利用等离子体聚合膜沉积技术和纳米金亚单层自组装技术设计传感器界面，用 于固定羊抗人M抗体，研制了一种新的M压电免疫传感器．先在石英品振上沉积正丁 胺等离子体聚合膜，通过戊二醛交联结合一半肮胺单层膜，利用膜上流基与纳米金 键合组装纳米金亚单层，得到可用于固定18kI抗体的界面，再以牛血清白蛋白 (BSA)和聚乙二醇(PEG)封闭晶振上的非特异性吸附位点．实验探讨了影响纳米金自 组装和抗体包被等主要实验参数和条件；考察了采用此固定化方法传感器的响应性 能，与戊二醛共价交联固定法和金电极表面直接吸附固定法进行了比较．结果表明 ，以纳米金单层作界面固定抗体时，具有传感界面不需活化、固定抗体的活性高、 检测时的非特异性吸附小、传感器能反复再生等优点．将传感器用于实际样品的检 测，结果令人满意．     

液晶型非标记免疫传感器检测天蚕素B

制备了一种基于液晶取向变化的非标记液晶型免疫传感器,用于检测天蚕素B。首先采用硅烷化试剂自组装膜法构建基底敏感膜诱导液晶分子呈均一垂直排列,再通过戊二醛交联法将天蚕素B固定到基底表面,当天蚕素B抗体与天蚕素B特异性结合后扰乱了液晶分子的取向,使液晶膜的颜色和亮度发生变化,以此实现对天蚕素B的检测,检测限可达0.1 ng/m L。本方法具有灵敏度高、特异性好、非标记和操作简单等优点。     

基于电聚合膜和纳米金自组装的生物分子固定化新方法的研究

结合电聚合膜和纳米金自组装技术,提出了一种新的生物分子固定化方法,研制成一种检测抗胰蛋白酶的压电免疫传感器。通过在石英晶振金电极表面电聚合邻苯二胺膜,再在膜表面自组装一层纳米金粒．以静电吸附作用固定抗体(抗原),实现对相应抗原(抗体)的检测。利用扫描电镜技术,从形态上考察了晶振金电极上自组装纳米金后的表面形貌。研究了抗体的固定化条件,探讨了传感器的响应与再生性能结果表日月．这种固定化方法对所固定的生物分子的生物活性影响小,传感器的测定灵敏度高．响应性能和再生性能较好。     

基于酶催化沉积放大的电化学阻抗法用于人免疫球蛋白M的检测

提出了一种基于酶催化沉积放大的电化学免疫分析方法。先通过免疫夹心反应,将酶标抗体(羊抗人IgM-HRP)固定到电极表面。通过HRP催化双氧水氧化3,3′-二氨基联苯胺在电极表面形成不溶性沉积物,从而放大电化学检测信号。实验通过蛋白A实现抗体的定向固定。考察了包被抗体的浓度和包被溶液的pH对抗体固定的影响,以及酶标抗体的用量和沉积时间对免疫分析的影响。传感器信号响应与人免疫球蛋白M(IgM)浓度在2.1~670μg/L范围内具有良好的线性关系;检出限达0.08μg/L。     

压电免疫传感器法检测蓖麻毒素

利用纳米金对石英晶体微天平(QCM)的表面修饰和质量扩增效应,建立了一种压电免疫传感器检测蓖麻毒素的新方法。首先在石英晶体的金电极上依次自组装1,6-己二硫醇和纳米金进行表面修饰,然后通过蛋白A定向固定蓖麻毒素多抗来制备敏感膜。利用纳米金的质量扩增效应设计了一种“毒素-单抗-蛋白A-纳米金”复合物,成功实现了对蓖麻毒素的检测,提高了传感器灵敏度和特异性。该传感器对蓖麻毒素响应的线性范围为0.50~10 mg/L,回归方程为△F=45.81Cric in 48.48(R=0.9986,N=10,P<0.01);检测灵敏度为45.81 Hz/(mg/L)。     

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.