阵列式对电极介电电泳芯片及其用于细胞分离富集研究

基于介电电泳原理, 设计并制作了一种新型的能够用于细胞分离和富集的微流控介电电泳芯片. 该芯片由沉积有金电极的石英基片和带有微管道的聚二甲基硅氧烷(PDMS)盖片组成. 通过在管道底部布置间距不同的对电极阵列, 增大了正介电电泳力在管道中的有效作用范围, 能够在降低施加电压的同时, 实现对流动体系中细胞样品的捕获. 在3 V和3 MHz条件下, 该DEP芯片对人血红细胞的捕获效率达到83%; 进一步通过将肝癌细胞捕获在芯片电极上可实现对红细胞和肝癌细胞混合样品的分离, 在5 V和400 kHz条件下对肝癌细胞的捕获效率达到86%.     

生化样本的芯片介电电泳富集和分离研究进展

芯片介电电泳技术是以介电电泳(DEP)分离原理和微机电加工技术为依托发展起来的可用于生化样品分析的新型分析技术.本文概述了芯片介电电泳技术的发展和DEP芯片分析系统的构成,并以DEP操控模式为切入点,介绍了芯片介电电泳在生化样品分析中的应用情况.     

介电电泳芯片及其在细胞分析中的应用

简要阐述了在交流和直流电压电场中,介电电泳(DEP)芯片进行细胞分离富集的机理.按照驱动电场的差异对DEP芯片进行了分类,分析和比较了DEP芯片微电极的叉指电极、抛物线电极、堡式电极、三维电极等典型结构.特别对近年来DEP芯片在单细胞分析、细胞分离与富集以及临床细胞分析中的应用进展进行了综述,并对其应用前景和发展方向进行了展望.     

基于介电电泳的微流控细胞分离芯片的研究进展

细胞分离技术是细胞分选和细胞种群纯化的重要手段,在生物、医学、农业、环境等许多领域都有重要的应用,是当前生化分析领域的国际研究热点。本文介绍了基于介电电泳的微流控细胞分离芯片的研究现状,阐述了介电电泳的工作原理,并依据细胞尺寸、电极形状、外加信号方式等影响细胞介电电泳的关键因素对不同类型的微流控细胞分离芯片进行了详细介绍,并对该技术的未来发展趋势做了展望。     

基于芯片介电电泳的细胞特性分析及种类判断

基于微流控芯片介电电泳( Dielectrophoresis,DEP)原理和技术,在自行设计制作的抛物线电极结构的微流控介电电泳芯片上,采用芯片介电泳临界频率测定法,选择缓冲液电导率为200～1000 μS/cm,激发电压为5V,分别对红细胞(RBC)、白细胞(WBC)和死活HepG2肝癌细胞的临界频率进行了测试,检测...     

基于SOI基底的高通量细胞电融合芯片

提出了一种以MEMS技术为基础, 可在低电压驱动条件下工作的创新型细胞电融合芯片. 该芯片的设计原理在于通过缩短微电极间的间距, 在低电压条件下获得足够强度的排队和融合电场强度. 原型芯片以SOI硅片为加工材料, 通过刻蚀方式在顶层低阻硅形成微电极和微通道; 在微电极上沉淀2 μm厚的铝膜以降低电阻率, 提高导电性; 通过PECVD方法形成150 nm厚SiO2保障铝膜的抗腐蚀性及芯片生物相容性; 芯片最终采用DIP法进行封装. 在该芯片上进行了低电压(传统电融合设备工作电压的1/20)驱动条件下的基于介电电泳的细胞排队实验及后期的细胞电融合实验, 结果表明, 细胞多以两两结合的方式排列, 与传统的细胞融合电仪器相比较, 降低了多细胞排队概率, 进而减少了传统电融合设备多细胞融合的概率, 为细胞高效率融合奠定了基础. 在加载的低电压短脉冲信号后, 微通道中形成了高压短脉冲电场, 在脉冲作用下, 烟草原生质体细胞在微通道中发生了融合, 融合时间(2 min)远低于传统电融合方法(10~30 min), 融合率远远高于传统的PEG方法(融合率小于1%)和传统电融合方法(利用BTX ECM 2001细胞电融合系统得到, 融合率小于5%).     

用于细胞排列的介电泳微流控芯片制备与实验研究

设计并制作了一种应用于细胞排列的介电泳微流控芯片,以实现细胞的非接触、批量排列。芯片主要包括PDMS微通道和“台阶”形ITO微电极。运用仿真软件COMSOL分析了微电极所形成的电场分布,确定了最大电场强度的位置;利用MEMS加工工艺制备了ITO微电极和PDMS微通道,PDMS微通道与带有ITO电极的载玻片经过氧等离子表面处理后,对准键合获得最终的微流控芯片。通过不同频率下的介电泳实验,实现了酵母菌细胞的介电泳运动,并确定了正、负介电泳运动的电场频率。结果表明,酵母菌细胞在溶液电导率为60μS/cm的环境下,1~10 kHz时,发生负介电泳运动;0.5~10 MHz时,发生正介电泳运动;50 kHz时,没有发生介电泳运动。并在施加8 Vp-p,5 MHz交流电压信号的条件下,实现了酵母菌细胞沿“台阶”形电极边缘直线排列。     

基于多层叉指超微带电极阵列的葡萄糖传感器

采用多层工艺和光刻方法在玻璃衬底上加工了亚微米级金叉指型超微带电极阵列（IDA）,IDA电极的宽度为362nm,电极表面位于沟槽内。实验表明,所加工的IDA电极可作为生物和化学传感器的一次性超微基体电极。采用电聚合的方法将葡萄糖氧化酶（GOD）和吡咯（PPy）固定于IDA电极,该修饰电极可作为葡萄糖传感器。采用该葡萄糖传感器对磷酸钾缓冲溶液（pH7．0）中的葡萄糖浓度进行了比对测量,在2．0-7．0mmol／L的浓度范围内,传感器的响应时间为10s;灵敏度为14．6nA／（mmol／L）,相关系数为0．999。     

基于叉指阵列微电极的阻抗免疫传感器研究进展

叉指阵列微电极(Interdigitated array microelectrodes,IDAM)具有检出限低、灵敏度高和信噪比好等优点,近年来在分析化学领域引起了极大的关注.阻抗免疫传感器将IDAM与免疫测定技术相结合,通过抗原抗体的特异性反应引起IDAM之间介质的阻抗变化实现对目标物的检测.本文分析了 IDAM的...     

Practical Insights into the Impedance Response of Interdigitated Electrodes: Extraction of Relative Static Permittivity and Electrolytic Conductivity

This work aims to provide a detailed understanding of the challenges related to the computation of the relative static permittivity and electrolytic conductivity of a sample medium from its impedance response recorded with interdigitated electrode (IDE) geometries. Within the scope of the study, impedance data has been measured and evaluated for a total of nine sample media using two distinct IDE geometries. Particular emphasis is laid upon the compensation of parasitic influences affecting the impedance response. With the raw data supporting this study fully disclosed, the reader is offered the opportunity to comprehensively retrace the evaluation procedure proposed in the text.     

A Novel Impedimetric Biosensor for Detection of Lead (II) with Low‐cost Interdigitated Electrodes Made on PCB

A novel, low‐cost, label‐free impedance biosensor based on gold interdigitated electrodes (GIE) was developed for detection of lead. This sensor was developed by immobilizing GR‐5 DNAzymes onto the GIE surface through Au‐S bonding. In the presence of lead, the substrate strand was cleaved into two parts at the RNA site (rA) and caused changes in the interfacial properties of the GIE, resulting in a corresponding decrease in the impedance magnitude. Thus, by measuring the decrease, the concentration of lead ion can be determined. And coupled the GIE with GR‐5 DNAzyme recognition, our proposed lead biosensor exhibited a high sensitivity with a detection limit of 6.61 nM, which is much lower than the 72 nM defined as the maximum contamination level (MCL) of lead ions in drinking water by The United States Environmental Protection Agency (EPA), at the same time, with a linear range from 10–100 nM and a prominent selectivity against other heavy metal ions. What's more, different from the traditional way, the GIE are made on printed circuit board (PCB), this makes the biosensor has the advantages of simplicity, low cost and easy mass production, and it can easily be widely used.     

Electrochemical Sensing Platform Integrated with Solid-state Reference Electrode Based on Indium Tin Oxide Interdigitated Array Electrodes

We present a new strategy for the fabrication of a fully integrated electrochemical platform. The three-electrode system consists of an indium tin oxide interdigitated array as working electrode, a solid-state reference electrode, and an electrodeposited Pt counter electrode that are placed in microfluidic channel. By controlling the electrodeposition conditions, such as the applied potential and time, the stability and uniformity of the films can be optimized. A solid-state reference electrode was fabricated on the nanoporous Pt via electropolymerization of poly-1,3-phenylenediamine. This system provides a simple method for the fabrication of three-electrode system and opens the possibility for an electroanalytical platform.     

基于阵列微流控细胞芯片的植物组分抗氧化活性分析

设计并制作了一种集成有8个重复6×6细胞培养单元的阵列微流控细胞芯片,以实现细胞培养和系列植物组分的细胞抗氧化活性(Cellular antioxidant activity,CAA)分析.芯片主要包含聚二甲基硅烷盖片、288个圆形培养腔体,48个独立平行通道的玻璃基底层,一次可完成8个样本的6个浓度筛选,并可在酶标仪上实现测试.槲皮素、芦丁和山奈酚等植物组分与芯片上培养的细胞作用24 h,细胞存活率大于90％.以芯片上培养的人肝癌细胞HepG2为细胞载体,以2',7'-二氯荧光素-乙酰乙酸酯(2',7'-Dichlorofluorescin diace-tate,DCFH-DA)为荧光探针,采用2,2'-偶氮二异丁基脒二盐酸盐(2,2'-azobis(2-amidinopropane)dihydrochlo-ride,ABAP)为细胞内活性氧(Reactive oxygen species,ROS)引发剂,测得槲皮素、芦丁、山奈酚等植物组分的CAA unit分别为71.42±0.19、74.31 ±0.36和69.92±0.09((x)±s,n=3),IC50分别为(7.20±0.06) μmol/L,(52.06±0.14) μmol/L,(32.55±0.03) μmol/L((x)±s,n=3).     

Dye‐Sensitized Solar Cell Counter Electrodes Based on Carbon Nanotubes

Dye‐sensitized solar cells (DSSCs) have received significant attention from the scientific community since their discovery in 1991. However, the high cost and scarcity of platinum has motivated researchers to seek other suitable materials for the counter electrode of DSSCs. Owing to their exceptional properties such as high conductivity, good electrochemical activity, and low cost, carbon nanotubes (CNTs) have been considered as promising alternatives to expensive platinum (Pt) in the counter electrode of DSSCs. Herein, we provide a Minireview of the CNTs use in the counter electrode of DSSCs. A brief overview of Pt‐based counter electrodes is also discussed. Particular attention is given to the recent advances of counter electrodes with CNT‐based composite structures.     

Microchip electrophoresis of N-glycans on serpentine separation channels with asymmetrically tapered turns

We designed and fabricated microfluidic devices with serpentine separation channels and asymmetrically tapered turns, thus allowing high efficiency separations and minimizing band broadening associated with the “racetrack” effect. We evaluated the performance of these devices by measuring the variation in separation efficiency with separation length, electric field strength, taper ratio of the turns, and number of turns. N‐Glycans derived from ribonuclease B and labeled with 8‐aminopyrene‐1,3,6‐trisulfonic acid were electrophoretically separated on serpentine channels with separation lengths of 11, 18, 22, and 36 cm at electric field strengths from 750 to 1750 V/cm. Separations on the 36‐cm channel produced plate numbers up to 940 000 with an analysis time under 3.1 min, whereas separations on the 22‐cm channel had a shorter analysis time (less than 1.25 min), still with respectable efficiencies (up to 600 000 plates). Turn‐induced dispersion was minimized with taper ratios 2 and 3, whereas having two or four 180° turns along with the separation length did not impact the overall efficiency. The developed device was used to analyze native and desialylated N‐glycans derived from the blood serum of an ovarian cancer patient and a disease‐free individual. Separation efficiencies similar to that achieved with the model glycans from ribonuclease B were attained for these biological samples.     

无泵负压进样-芯片电泳分离-激光诱导荧光光谱法测定儿茶酚胺类物质

提出了用芯片电泳分离-激光诱导荧光光谱法测定儿茶酚胺类物质的方法。采用自制的无泵负压进样系统,避免了进样歧视效应。在优化的条件下,去甲肾上腺素(NE)、多巴胺(DA)和肾上腺素(E)可在1 min内完全分离。3种儿茶酚胺的平均迁移时间依次为30.59,37.23,46.43 s,其相对标准偏差(n=7)依次为1.10%,1.28%,0.45%。3种物质的线性范围为0.3～5.0 mg.L-1(NE及DA)和0.05～4.0 mg.L-1(E),检出限(3S/N)依次为30,30,10μg.L-1。