一种用于乳酸检测的新型微流控芯片

基于光度吸收原理,设计了一种集成片上混合和光纤检测功能于一体的微流控芯片,用于细胞和组织培养过程中乳酸代谢浓度的在线检测。通过光学设计软件(Zem ax)优化设计了吸收光路,得到微流控芯片沟道宽度为250μm,利用计算流体动力学软件(CFD)模拟确定了乳酸和显色剂片上混合时微流控芯片沟道的溶液完全混合位置和光纤检测点,采用微电子机械系统(MEMS)加工了基于聚二甲基硅氧烷(PDMS)的微流控芯片,将片上混合和光纤检测功能集成在一个以PDMS和载玻片组成的芯片上。实验结果表明,该芯片成功实现了乳酸和显色剂的片上混合和实时检测,检出限(LOD)为0.52 mmol/L(47 mg/L),乳酸浓度从1 mmol/L变化至5 mmol/L时的芯片响应时间为130 s,能够满足细胞和组织培养过程中乳酸在线检测要求。     

毛细管电泳芯片简化安培检测系统的研制

摘要开发出一种新型电化学检测器,该检测器具有噪声低、基线漂移小、检测限低、整体体积小及便于现场使用等优点.在集成ITO电极的PDMS/玻璃毛细管电泳芯片上,利用多巴胺标准样品对该检测器的性能进行了评价.     

用于细胞三维培养的集成微柱阵列的微流控芯片设计与验证

设计并验证了一种用于细胞三维培养的集成微柱阵列的微流控芯片.芯片由一片聚二甲基硅氧烷(PDMS)沟道片和一片玻璃盖片组成, 在PDMS沟道片上集成了一个由两排微柱阵列围成的细胞培养室和两条用于输送培养基的侧沟道.微柱间距直接影响了芯片的使用性能, 是整个芯片设计的关键.基于数值模拟和实验验证, 本研究对微柱间距进行了优化设计.优化后的微流控芯片可以很好地实现细胞与细胞外基质模拟材料混合液的稳定注入、培养基中营养物质向培养室内的快速扩散和细胞代谢物的及时排出.在芯片上进行了神经干细胞的三维培养, 证明了芯片上构建的细胞体外微环境的稳定性.     

基于ARM9的便携式电容耦合非接触电导检测器

研制了一种应用于微流控芯片的便携式电容耦合非接触电导检测器。此检测器在ARM9嵌入式平台上开发,所有功能由ARM9微处理器控制完成。检测器的硬件部分主要包括信号激励、信号调理、信号采集处理及显示单元;软件部分主要包括操作系统、驱动程序和应用程序。检测器的激励信号频率范围为0～2 MHz;电压范围为0～20 Vpp(峰峰值);检测器的外形尺寸为130 mm×102 mm×35 mm。利用此检测器测试了一种三层结构微流控芯片的检测灵敏度。该芯片由聚甲基丙烯酸甲酯电极片(包含铜检测电极)、厚度为16μm的聚二甲基硅氧烷(PDMS)绝缘层和PDMS沟道片(包含微沟道)组成。溶液在蠕动泵的驱动下,从芯片的尖端进入微沟道,并在电极处得到检测。本研究对检测器的激励频率和电压进行了优化。在优化的激励频率(50 kHz)和电压(20 Vpp)下,得到的KCl检出限为9.1μmol/L。     

基于三维纳米银修饰电极的硝酸根微型传感芯片研究

研制一种基于金叉指微电极阵列(IDA)的电流型硝酸根离子(NO-3)微传感电极芯片.基于微机电系统(Micro-Electro-Mechanical Systems,MEMS)工艺制备金IDA微电极,通过电化学沉积技术在IDA微电极表面修饰三维枝状结构纳米银敏感膜,利用敏感膜对硝酸根离子良好的电催化还原性能,采用脉冲方波伏安(SWV)电化学测量方法,实现对硝酸根离子在25～1000μmol/L浓度范围内的快速检测,灵敏度达9.5 nA/(μmol/L),线性度为99.98%,检测下限为10μmol/L.考察水体中常见的NO-2,F-,3PO 4-,SO 42-,2CO3-,NH+4,Na+和K+等离子对该传感芯片的干扰性能,传感芯片表现出较好的抗干扰性能.制备的三维枝状结构纳米银修饰IDA微电极可实现水环境(pH 5.0～9.0)中NO-3的电化学检测,对应用于自然水环境中硝酸根离子的现场检测具有积极意义.     

一步合成花朵形状的Au纳米结构以及在电化学测定多巴胺方面的应用

通过水热法在导电玻璃表面一步合成花朵形状Au纳米结构。以此花朵形状Au纳米结构修饰电极为工作电极来组装多巴胺传感器;电化学数据显示花朵形状Au纳米结构能够加速电子在多巴胺和电极表面传递,减少电化学氧化过程中的过电位,多巴胺的浓度在1.25μmol/L~1.07 mmol/L范围内,氧化峰电流与浓度存在线性关系(R=0.997),检测限为0.61μmol/L。合成的电化学传感器具有良好的稳定性和重复性,为多巴胺的实际分析检测提供了一种新方法。     

新型芯片电泳柱端安培检测系统的构建与评价

自行设计开发了一套便于与电泳芯片集成的一体式柱端安培检测池系统．该系统由整块透明有机玻璃精密加工而成,包括电泳芯片支架和安培检测池两部分,芯片可通过芯片插槽和不锈钢夹具固定在芯片支架上,各种检测用电极可直接通过螺母固定在安培检测池中．以100μmol／L的DA为模式分析物,分别采用直径为100、300和500μm的铂金圆盘电极与表观直径为240μm的碳纤维电极作为工作电极均在该装置上实现了良好组装和高灵敏检测．采用碳纤维工作电极对该系统的检测参数进行了优化．测试结果表明该系统在电化学清洗程序下连续六次测定100μmol／L多巴胺的峰电流相对标准偏差为3．2％,保留时间相对标准偏差为0．5％,DA的检测限为0．4μmol／L（按照S／N=3计）．该系统体积小巧,测试稳定,检测灵敏度较高,工作电极更换方便,适合作为芯片电泳柱端安培检测通用平台．     

柱端安培检测毛细管电泳芯片及其初步应用

采用两步蚀刻技术制作集成工作电极导管的毛细管电泳芯片,30 μm直径的碳纤维微电极通过导管与分离通道末端对齐和固定,芯片上还制作了阴极通道以固定电泳负极.以神经传递物质多巴胺(DA)和邻苯二酚(CA)表征制作的芯片,DA和CA测定的线性范围为5~200 μmol以及20~800 μmol,检测限分别是0.51和2.9 μmol(S/N=3).三种酚类的检测结果表明该芯片可应用于环境样品的分析.     

适用于海洋沉积物间隙水中氧、锰(Ⅱ)、铁(Ⅱ)、硫分析的金汞齐微电极

用电化学方法在金微电极的基础上制成金汞齐微电极。研究了电极预处理方法、电镀以及强极化金汞齐微电极的条件、电极的校正方法以及实际测量电化学参数的选择等。采用三电极体系和方波伏安法,金汞齐微电极(vs.SCE)从-0.10～-1.75V电势范围内可同时测定沉积物间隙水中的溶解氧、Mn2 、Fe2 和S2-等氧化还原物的浓度。实验结果表明金汞齐微电极对溶解氧、Mn2 、Fe2 和S2-的灵敏度和检出限分别为0.16nA/(μmol/L)、6μmol/L,0.35nA/(μmol/L)、3μmol/L,0.22nA/(μmol/L)、5μmol/L和34nA/(μmol/L)、0.03μmol/L。在连续测定15个沉积物样品后,重新校正电极,测量相对误差<3%。     

片层石墨柱电极制备及其对多巴胺的电化学检测

采用循环伏安法在HNO_3溶液中对石墨柱电极进行处理,制备得到被石墨片层均匀包覆的石墨柱电极。通过X射线衍射仪(XRD)和扫描电子显微镜(SEM)对片层石墨柱电极的组成和结构进行了表征。采用循环伏安、恒电位等方法研究了片层石墨柱电极对多巴胺(DA)的传感性能。研究结果表明:在多巴胺浓度为5～400μmol/L范围内,片层石墨柱电极的氧化峰电流与浓度存在良好的线性关系,检测灵敏度高达0. 446μA/μmol·cm~2。此外,片层石墨柱电极还具有良好的抗干扰能力、重现性和稳定性。     

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.     

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.     

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.     

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.