阵列微流控浓度梯度网络用于细胞-化学刺激反应研究

设计和制作了具有5组平行浓度梯度形成网络和30个细胞培养池的微流控芯片,该芯片集成了细胞接种、培养、梯度浓度化学刺激、标记和检测等功能单元。芯片为玻璃-PDMS杂合结构,微流控通道刻蚀于玻璃层。芯片细胞培养池设计了系列围堰结构以利于细胞贴壁。细胞接种、灌流培养和试剂引入通过外接微量注射泵控制完成。该芯片可以生成连续、稳定的平行浓度梯度。观察发现,围堰结构有利于细胞接种和生长,乳腺癌MCF-7细胞在芯片灌流培养条件下生长良好。利用该芯片检测了在接受As2O3和乙酰丝氨酸(NAC)梯度浓度刺激后乳腺癌MCF-7细胞内谷胱甘肽(GSH)水平以及细胞阿霉素敏感性的变化,分析乳腺癌细胞阿霉素敏感性与细胞内GSH水平的关系。MCF-7细胞内GSH水平的变化与刺激药物浓度呈剂量-效应依赖关系,在接受As2O3刺激后GSH水平有所下降;而在接受NAC刺激后GSH水平有所升高。MCF-7细胞阿霉素敏感性与GSH水平相关。在降低GSH水平后药物敏感性升高;而升高细胞内GSH水平后敏感性降低。这种阵列微流控浓度梯度网络可以用于高通量细胞-化学刺激反应研究,有潜力成为细胞水平大规模药物筛选的技术平台。     

微流控-热电极系统检测水中苯酚

利用集成热电极的微流控芯片进行了苯酚的检测,在优化条件下得到苯酚的线性方程为Y=37.49c+2.16×10-4,相关系数为R=0.9918,检出限为5×10-8mol/L。热电极提高了检测的灵敏度且改善了重现性。由于微芯片具有便携性好、成本低廉等优点,可用于野外及生产现场等苯酚的含量测定。     

CO2激光直写加工聚合物微流体芯片的建模研究

在CO2激光直写聚合物(PMMA)微流体芯片加工原理基础上,对激光直写PMMA微流道的数学模型进行了研究.采用能量守恒原理对激光直写PMMA微流道成型进行分析,结果表明,其微流道的形状呈高斯函数型分布,并获得了微流道深度和激光功率、加工速度的函数关系及微流道截面形状的数学模型.实验数据较好地验证了所建模型的正确性,该模型对CO2激光直写聚合物(PMMA)微流体芯片的加工工艺具有很好的指导作用.     

聚合酶链式反应微流控芯片的准分子激光制备和应用研究

摘要采用价格便宜的聚甲基丙烯酸甲酯(PMMA)代替价格昂贵的硅或玻璃作为聚合酶链式反应(PCR)微流控芯片的基片材料,采用柔性大且自动化程度高的准分子激光微加工方法代替加工工艺复杂的光刻化学腐蚀方法,在19 kV和18 mm/min的优化加工参数下,在48 mm×67 mm×1 mm的PMMA基片上制备出20个循环的PCR微流控芯片. 芯片微通道横截面呈梯形,底面光滑. 微通道宽104 μm,深56 μm,长2 060 mm,加工耗时约110 min. 该芯片和相同尺寸的盖片在160 N和105 ℃条件下通过热压经20 min键合在一起,键合强度为0.85 MPa. 键合后的芯片和温控系统集成在一起,采用比例积分微分(PID)方法得到的控温精度为±0.2 ℃,采用红外热像仪得到的相邻温区间的温度梯度分别为16.5和22.2 ℃,最后利用该芯片在对170 bp的DNA片段实现了体外扩增.     

微流控芯片中超微电极的制作及其在芯片-电化学检测中的应用

设计并制作了集成有超微电极的玻璃微流控芯片.在电化学检测芯片1(EC-1)中,以光刻方法制作13μm宽的Pt超微电极,距分离管道末端30μm,优化电极体系和分离电压,检测了电泳分离的神经递质.在电化学检测芯片2(EC-2)中,制作7μm宽的超微电极,在其上游集成城墙式的膜结构,进一步腐蚀后的膜厚度为10μm,具有良好的导电性和散热性能,成功地将高压电场截至在超微电极之前,具有进一步应用于电化学检测的能力.     

微电极阵列芯片的脂质体电融合研究

利用旋转蒸发法制作基于大豆卵磷脂的一种大型脂质体,在微电极阵列芯片上进行脂质体电融合实验研究.在电融合过程中,利用介电电泳力实现脂质体在微流控芯片中的排队,再利用高场强的电脉冲使脂质体膜发生可逆性电穿孔,在持续的介电电泳力作用下,使穿孔的脂质体实现融合.芯片上脂质体的融合率可以达到20％左右.而且,玻璃基底材料和低深宽比的通道结构更有利于脂质体融合过程的观察与控制.     

脉冲CO2激光诱导异丙醇复相解离反应

近年来,激光诱导复相催化反应引起了人们的重视,该方面的工作已有一些报道,如CWCO_2激光诱导甲酸分子在热铂丝上的分解反应,脉冲CO_2激光诱导BCl_3分子与吸附在钛上的H_2的反应以及NH_3在铂表面的复相氧化反应。Farneth等人曾报道了在红外激光垂直照射灼烧过的铜片时,气相异丙醇分子的复相分解反应。本文以活性氧化铜粉末为催化剂,激光光束平行于催化剂表面辐照(光束不接触催化剂表面),测定了激光频率,能量密度等多种因素对异丙醇复相反应的影响。     

一种微流控芯片激光诱导荧光检测器的研制及应用

研制了一台正交结构的微流控芯片激光诱导荧光检测器.将较宽的芯片架固定在1个三维操作平台上,可用于检测点的调节和激光光斑校准微调.不同发射波长的半导体激光器以及不同波长的窄带滤光片均可方便更换,以满足不同品种的分析要求.该检测器结构简单、体积小和操作灵活方便,对微流控芯片的尺寸及通道结构适应性强.能在一定程度上满足多种芯片的应用研究需要.     

一种简单的微流控芯片正交型激光诱导荧光检测系统

对微流控芯片检测技术的研究一直是近年来微全分析系统领域的研究热点.激光诱导荧光(Laser induced fluorescence,LIF)检测技术因其具有较高的灵敏度,成为目前微流控分析芯片采用最广的检测方法^[1].     

通用型激光诱导荧光微流控芯片分析仪的研制与性能考察

设计和研制了一种通用型激光诱导荧光微流控芯片分析仪.检测部分按共聚焦检测原理设计,采用CCD(电荷耦合器件)监测通道,三维自动调节聚焦,发射波长滤光片可方便地更换以适应多种染料选择,能分别显示进样和分离通道2条电流-时间曲线.考察了该分析仪的检测灵敏度、检测极限和线性范围,显示了分析灵敏度高,检测限低和线性范围宽等特点,在自制注塑型PMMA塑料芯片上实现了φX174Haedi-gesT_dNA片段的分离测定和烟叶act基因PCR产物的分析     

胞嘧啶吸附在粗糙金电极上的表面增强拉曼光谱

应用电化学伏安法和表面增强拉曼光谱(SERS)研究在-1.0 V~0 V电位区间内胞嘧啶于粗糙金电极表面的吸附行为.结果表明,在本实验的电位区间,胞嘧啶是以其N3位垂直吸附在粗糙金电极表面的.在负电位区间环呼吸振动模的强度出现极大值,与其它振动模强度相比,作者认为电磁场的增强和电荷转移均使该谱峰的拉曼信号增强.胞嘧啶的环呼吸振动频率随着电位负移而红移,这意味着它与金电极的成键作用减弱.同时也表明SERS谱可用于研究生物分子在金属电极表面的吸附行为.     

基于薄膜电极的细胞电融合芯片

构建了一种薄膜电极阵列结构的细胞电融合芯片, 通过多聚物微通道底/顶层凸齿状的微电极, 以及多聚物微通道侧壁上溅射形成的一层离散式金属薄膜电极, 共同形成离散式"三明治"微电极结构. 该微电极结构可在微通道内部形成与传统凸齿状电极相似的非均匀分布的梯度电场, 通过介电电泳效应进行细胞控制及排队. 利用多聚物在芯片上填充了传统凸齿状电极的凹陷区, 克服了细胞在凹陷区无法有效排队与融合的缺点. 在芯片上利用K562细胞开展了基于介电电泳效应的细胞排队实验及基于可逆性电穿孔效应的电融合实验, 结果表明该芯片能够较好地实现细胞排队及融合, 融合所需控制电压低至10 V左右. 细胞排队率达99%以上, 几乎无细胞在绝缘物填充区(传统凸齿电极芯片的凹陷区)滞留, 细胞两两排队高于60%, 细胞融合效率约为40%, 比传统的细胞电融合方法和凸齿电极芯片有较大提高.     

An Enzyme‐free H2O2 Sensor Based on Poly(2‐Aminophenylbenzimidazole)/Gold Nanoparticles Coated Pencil Graphite Electrode

A poly(2‐aminophenylbenzimidazole)/gold nanoparticles (P2AB/AuNPs) coated disposable pencil graphite electrode (PGE) was fabricated as an enzyme‐free sensor for the H₂O₂ determination. P2AB/AuNPs and P2AB were successfully synthesized electrochemically on PGE in acetonitrile for the first time. The coatings were characterized by scanning electron microscopy, X‐ray diffraction spectroscopy, Energy‐dispersive X‐ray spectroscopy, Surface‐enhanced Raman spectroscopy, and UV‐Vis spectroscopy. AuNPs interacted with P2AB as carrier enhances the electrocatalytic activity towards reduction of H₂O₂. The analytical performance was evaluated in a 100 mM phosphate buffer solution at pH 6.5 by amperometry. The steady state current vs. H₂O₂ concentration is linear in the range of 0.06 to 100 mM (R²=0.992) with a limit of detection 3.67×10^?5 M at ?0.8 V vs. SCE and no interference is caused by ascorbic acid, dopamine, uric acid, and glucose. The examination for the sensitive determination of H₂O₂ was conducted in commercially available hair oxidant solution. The results demonstrate that P2AB/AuNPs/PGE has potential applications as a sensing material for quantitative determination of H₂O₂.     

Anion Adsorption on an Au Colloid Monolayer Based Cysteamine-Modified Gold Electrode

IntroductionThe metal colloids have been investigated for over l40 years since Faraday['] made thefirst approach on gold colloids. Colloidal Au can be used for catalysis['], microanalysis of pro--tein and biosensors[3J and its fine particles have been expected to be a highly efficient thirdnon1inear optical material[4'5J. However, most studies on the surface chemistry of metal parti-cles have been focused on silver[6], the reason is that the plasmon absorption band of that met-al is very str…     

Fabrication of a Sensitive Impedance Biosensor of DNA Hybridization Based on Gold Nanoparticles Modified Gold Electrode

In this work, we report on the preparation of a simple, sensitive DNA impedance sensor. Firstly gold nanoparticles were electrodeposited on the surface of a gold electrode, and then probe DNA was immobilized on the surface of gold nanoparticles through a 5′‐thiol‐linker. Electrochemical impedance spectroscopy (EIS) was used to investigate probe DNA immobilization and hybridization. Compared to the bare gold electrode, the gold nanoparticles modified electrode could improve the density of probe DNA attachment and the sensitivity of DNA sensor greatly. The difference of electron transfer resistance (ΔR_et) was linear with the logarithm of complementary oligonucleotides sequence concentrations in the range of 2.0×10^?12 to 9.0×10^?8 M, and the detection limit was 6.7×10^?13 M. In addition, the DNA sensor showed a fairly good reproducibility and stability during repeated regeneration and hybridization cycles.     

Deposition Strategies for Osmium/Enzyme Films on Gold Electrode Based Sensing Arrays

Multi‐analyte real‐time interrogation of cellular activity allows for the potential discovery of novel insights into disease. In this report, the addition of electrochemical biosensors to a previously developed platform utilizing Au microfabricated electrodes was explored. Glucose oxidase was immobilized at the electrode surface with an osmium redox polymer, using hand‐casting and electrodeposition techniques, allowing for the first comparison of deposition techniques at a Au microfabricated array. This preliminary work is the first step toward the goal of creating a multi‐analyte array for cellular analysis.     

Electrochemical Morphine Sensor Based on Gold Nanoparticles Metalphthalocyanine Modified Carbon Paste Electrode

Composites of gold nanoparticles (Au) electrochemically deposited and different metal phthalocyanines (Co, Ni, Cu, and Fe) were chemically prepared. The composites were used as modifiers for carbon paste electrodes and were used for the determination of morphine in presence of ascorbic acid and uric acid. Central metal atoms of phthalocyanine moiety affected the rate of electron transfer. Thus, the electroactivity of different modifiers were evaluated towards morphine oxidation. Au‐CoPcM‐CPE possessed the highest rate for charge transfer rate in all studied pH electrolytes. Limit of detection was 5.48×10^?9 mol L^?1 in the range of 4.0×10^?7 to 9.0×10^?4 mol L^?1.     

三正辛胺修饰电极伏安测定痕量金的研究

用化学修饰电极伏安测定痕量金,Kalcher K等曾采用阴离子交换剂碳糊修饰电极及打萨宗碳糊修饰电极检测100～300μg/L的金。本文采用三正辛胺(TOA)修饰玻碳电极,在1.5 mol/L介质中,Au(Ⅲ)在+0.16 V(vs SCE)处有一灵敏的不可逆还原峰。检出限为0.1μg/L。灵敏度比文献方法高千倍。Au(Ⅲ)浓度在5×10~(-7)～5×10~(-9)mol/L范围内峰高与浓度     

对插型阵列微带电极的制作及其电化学特性研究

用微电子光刻方法制作了对插型阵微带电极（ＩＤＡ），并通过ＳＥＭ对ＩＤＡ电极进行了表征，将微Ａｇ／ＡｇＣｌ参比电极和微铂丝对电极固定在ＩＤＡ电极附近，构成了微电解池，考察了该电极的循环伏安及计时电流特性，并用微带电极的扩散理论和Ｃｏｔｔｒｅｌｌ 公式对ＩＤＡ电极的准稳太电流进行了处理，指出了它们之间产生偏差的原因，研究了ＩＤＡ电极的“发生－收集”效应，测定了该电极的屏蔽因子、反馈因子和收集效率。     

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.