湿法腐蚀硅制作PDMS微流控芯片

提出一种制作聚二甲基硅氧烷(PDMS)微流控芯片的方法。用15%四甲基氢氧化铵溶液各向异性腐蚀硅(100)制作模具,然后经过浇模,中真空键合得到PDMS微流控芯片。整个过程耗时约10 h。用SEM和激光共焦显微成像系统观察整个制作过程。分析了硅片模具及PDMS微流控芯片图案的一致性及粗糙度,结果表明硅片模具图案的相对标准偏差低于3%,表面粗糙度Ra是0.051 μm,PDMS微流控芯片相应的分别是1%和0.183 μm。用PDMS微流控芯片进行电泳分离试验,分离场强200 V/cm,在4.7 cm长的分离通道中,30 s内成功分离了四苯磺酸基卟啉(TPPS)和羧基钴酞菁(TCPcCo(Ⅱ))的混合样品。     

微流控芯片技术及其在检验医学中的应用

芯片实验室技术作为基因组学和蛋白质组学研究的一种新的技术平台 ,受到广泛重视。其中微流控芯片可用于基因组学和蛋白质组学的各个领域 ,包括基因表达分析、基因多态型分析和临床诊断等 ,可以完成样品的分离、反应和分析等所有步骤。基于毛细管电泳的微流控芯片技术可以更快地完成PCR产物分离。本文介绍微流控芯片技术的原理、研究进展及其在检验医学中应用     

微流控技术在自然水体检测中的应用研究

微流控技术消耗的样品和试剂量很小,其分析速度快、分离效率高及微型化等特点使其特别适合于自然水体的痕量成分分析及现场快速检测。利用微流控技术的毛细管电泳方法可在10分钟以内完成自然水体中常见的正离子或负离子的分离富集检测,检测灵敏度满足标准要求。选用适合的背景电解质和优化的测试条件,微流控技术可以有效解决自然水体监控对常见离子及痕量元素分析的需求。     

微流控芯片二维电泳分离分析系统研究进展

微流控芯片分析系统(微全分析系统)近年来发展迅速,已经被应用于生物、环境样品的分离分析研究。多维分析系统能够极大地提高峰容量,适合于复杂样品体系的分离分析。在微流控芯片上进行的分离操作不仅可以有效地实现两种分离模式之间的零死体积切换,而且能够使分析速度与峰容量的矛盾得到补偿。本文对微流控芯片二维电泳分离分析系统的近期发展作综述,并展望其可能的发展前景。     

基于单电动机驱动的微流控芯片及其控制系统的设计

为解决在低聚焦流速下实现微流控芯片的高效聚焦和快速筛选功能及微流驱动控制系统小型化、低成本等技术问题,设计了一种微流控芯片及其微流驱动控制系统。该微流控芯片由控制层、PDMS薄膜层、流体通道层和玻璃基底等4层组成,流体通道层设置有1个主通道和3个分选通道,微流驱动控制系统中的液流控制装置采用单电动机时序驱动3个柱塞泵工作,控制层的热膨胀微阀门控制3个分选通道的开关。该微流控芯片及驱动系统实现了不同检测物的自动检测、聚焦、前进、静止、归类和筛选等功能。     

微流控芯片测定阿司匹林中乙酰水杨酸含量

本文利用自制微流控芯片测定阿司匹林中乙酰水杨酸含量,讨论影响测定的多个因素,同时用药典法和常规电导滴定法验证测定结果的可靠性,为微型全分析系统整体集成和样品现场分析奠定一定理论与实验基础。     

微流控芯片在医学检测中的应用

近年来,微流控芯片以其快速分析,低消耗,微型化和自动化等特点发展非常迅速。本文对微流控芯片技术做了简要的介绍,讨论了其在医学检测领域的应用。并重点分析了可用于医学检测的微流控芯片技术。包括Ca^2＋、NO^2＋等离子的分离与检测,葡萄糖、尿酸等代谢物的测定。     

多通道微流控电泳芯片CCD检测系统

针对微流控电泳芯片检测系统微型化、集成化的要求,分析了传统电泳芯片检测系统的优势和不足,提出一种以FPGA芯片为控制器的CCD多通道微流控电泳芯片检测系统。利用FPGA/NiosⅡ嵌入式系统解决方案,以EP2C8Q208芯片为核心,设计了CCD驱动及外围硬件电路。通过上位机软件进行数据处理,实现了荧光图谱的同步显示。实验结果表明:该系统能同时检测多通道微流控电泳芯片中各通道不同的荧光信号强度,具有较高的灵敏度和信噪比,对罗丹明B样品的最低检测浓度为1.0×10-6mol/L,能够满足多通道微流控电泳芯片检测的要求。     

一种微流控细胞分离芯片及其流场分析

微流控细胞分离芯片中流场的分布对混合细胞的有效分离有非常重要的意义,是细胞分离芯片结构设计的一个重要因素.本文设计了一种细胞分离芯片,用于将细胞融合实验后的融合细胞从大量未融合细胞中自动分离出来.为进一步研究芯片中流场分布与芯片结构的关系,利用CFD分析软件Fluent对微流控细胞分离芯片中的流场进行仿真分析,得到其流速分布.针对微通道中的流动情况实验分析表明,实验与仿真结果相比误差在10%以内,证明了CFD软件仿真在细胞分离芯片结构的设计中的指导作用.通过对仿真结果的对比分析,选择了一个优化的芯片结构模型并制作了Y型通道的微流控分离芯片.     

微流控芯片的键合技术与方法

键合是将组成微流控芯片的基片和盖片以某种方式结合在一起,从而形成封闭的微通道的一种装配方法。键合质量直接影响到微通道中流体的运动形态,从而影响检测效果,因此键合是微流控芯片制作过程中非常重要的环节。综述了现有的微流控芯片键合技术和方法,分析了各种键合技术和方法在键合质量、键合效率以及操作简便性等方面的特点,为不同材质、不同应用领域的微流控芯片选择适用的键合方法提供了技术指南,对键合技术的未来发展进行了分析和预测。     

Fabrication and characterization of thermally actuated bimorph probe for living cell measurements with experimental and numerical analysis

This paper deals with a novel structure for single-cell characterization which makes use of bimorph micro thermal actuators combined with electrical sensor device and integrated microfluidic channel. The goal for this device is to capture and characterize individual biocell. Quantitative and qualitative characteristics of bimorph thermal actuator were analyzed with finite element analysis methods. Furthermore, optimization for the dimension of cantilevers and integrated parallel probe systems with microfluidic channels is able to be realized through the virtual simulation for actuation and the practical fabrication of prototype of probes. The experimental value of probe deflection was in accordance with the simulated one.     

聚合物微流控芯片激光加工及建模研究

在CO2激光直写聚合物PMMA微流控芯片加工原理基础上，对建立激光直写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微流道成形进行分析，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与激光功率、加工速度及加工次数的函数关系模型。实验数据较好地验证了所建模型的正确性，该模型对CO2激光直写聚合物微流控芯片的加工参数选择具有较好的指导作用。     

Microfluidic channel depth determination with Tywman–Green interferometer

A microfluidic channel is fabricated on a silica wafer using reactive ion etching (RIE). The depth of the microfluidic channel has been measured using a surface profilometer and a Twyman–Green interferometer (TGI) setup. The TGI setup which mainly consists of a 660-nm wavelength He-Ne laser source, glass cube beam splitter and two prisms produced interference fringes based on the optical path difference between two interfering beams when the microfluidic channel is inserted into one of the beams. The TGI setup that was developed has shown high repeatability when measuring microfluidic channel depth and also eliminates back injection into the laser source and alignment criticality. The TGI setup applied a single photodiode to detect the shifting of the bright and dark fringe produced from the interference of the TGI. The depth of microfluidic channel obtained from the TGI is 1.79?±?0.31 μm using fringe shifting and intensity measurements, while according to the surface profilometer the depth of microfluidic channel obtained is 1.67?±?0.07 μm. The resolution of the TGI is 0.25 μm and can still go well below that depending on the wavelength of the laser source. This research describes the capability of the TGI to perform depth measurements on a microfluidic channel of a silica substrate which can also be improvised for other microscale devices and applications.     

Easily fabricated magnetic traps for single-cell applications

We describe a simple and inexpensive method of fabricating single cell magnetic traps within a polydimethylsiloxane (PDMS) device. These traps were developed as part of an automated system that captures individual yeast cells in a microfluidic device and analyzes each cell as it buds. To make the traps, PdCl(2) catalyst is rubbed with vinyl foam onto plasma-patterned PDMS, and then Co-Ni-B alloy is electrolessly deposited onto the catalyst at a moderate temperature. We demonstrate individual yeast cell capture and estimate the capture force (1.9-4.4 pN) by measuring the flow speed required to remove the cell from its trap in a microfluidic channel.     

Design and manufacture of high-filling-efficiency microfluidic devices

In this study, we proposed an efficient method for mass production of high-filling-efficiency microfluidic devices. Precision machining was the main process of device fabrication. The commercially available SolidWorks software was adopted for structure design. Unigraphics software was then used to simulate the machining process. The simulated tooling file was then loaded into a CNC milling machine for mold production. The fabricated metal mold was used for pouring polydimethylsiloxane (PDMS) to obtain high-filling-efficiency microfluidic structures. Finally, plasma-assisted packaging was conducted to tightly bind the PDMS microfluidic structure to the glass substrate. Experimental results showed that the additional semicircular filling structure and expended fill-entry structure can efficiently enhance filling efficiency of the microchannel device. The incubation well array can be completely filled at a relatively short filling time. The proposed highly efficient filling microfluidic device possesses advantages, such as feasibility for mass production and cost effectiveness.     

Ultrasonic flow-through filtration of microparticles in a microfluidic channel using frequency sweep technique

Many studies have been conducted on the filtration of microparticles using the acoustic radiation force of ultrasonic standing wave. The present work concerns a flow-through particle filtration method by utilizing frequency varying ultrasound. The periodical frequency sweep of the ultrasonic standing wave translocates particles across a microchannel, where particles in fluid flow are filtrated without barriers. The present filtration technique in a microfluidic channel was proposed conceptually in the 1990s. However, its experimental realization on actual particles in a microfluidic channel has not been carried out in a notable way. Several sizes of polystyrene microspheres (10 μm to 90 μm) and silicon carbide (SiC) particles (37 μm) suspended in water were applied as a test sample. For filtration of those particles, a Y-branched microfluidic channel with one inlet and two outlets was made out of steel and acrylic as a form of modulized device. Ultrasound of a few MHz in band frequency (1.75 MHz to 3.05 MHz) was transmitted into one side of the channel wall to generate a standing wave field in fluid flow. The periodical frequency sweep operation showed successful filtration performance, whereby particles in water flowed into one outlet and purified water flowed into the other outlet of the Y branch of the channel.     

Fabrication of low-cost polydimethylsiloxane master from laminating foil for isotachophoresis separation on a chip

This article introduces use of laminating foils as the base for rapid polydimethylsiloxane master fabrication. The designs are punched directly to the foil structure with fabricated knife; therefore, the preparation time requires only a few minutes. This approach offers low-cost and variable possibility of master fabrication to produce microfluidic devices the size of dozens of microns. The resulting structures enable precise control of various device geometries, such as variable channel diameters and shapes in a single device. We describe the fabrication of microfluidic channels using these masters with polydimethylsiloxane polymer. The usability is demonstrated for the isotachophoretic separation of organic anionic dyes.     

PC微流控芯片黏接筋与溶剂的协同辅助键合

为了在微流控芯片上形成封闭的微通道等功能单元,克服热压键合中微流控结构的塌陷和热压所致芯片微翘曲对后续键合的影响,提出了一种适用于硬质聚合物微流控芯片的黏接筋与溶剂协同辅助的键合方法。以聚碳酸酯(PC)微流控芯片为研究对象,通过热压法在PC微流控芯片上的微通道两侧制作凸起的黏接筋,通过化学溶剂丙酮微溶PC圆片的表面,然后将PC圆片与带有黏接筋的PC微流控芯片贴合、加压、加热,从而实现微流控芯片的键合。分析了键合机理,并对键合工艺参数进行了优化。实验结果表明:键合质量受丙酮溶剂溶解PC圆片的时间和键合温度的影响,能够保证键合质量的最佳键合温度为80~90°,溶解时间为35~45s,芯片的键合总耗时为3min。与已有键合工艺相比,所提出的黏接筋与溶剂辅助键合工艺有效提高了键合效率。该键合方法不仅适用于具有不同宽度尺寸微通道的微流控芯片,还可扩展用于不同材料的硬质聚合物微流控芯片。     

Optical detection of red blood cell aggregation in a disposable microfluidic channel

The aggregability of red blood cells (RBCs) was determined by laser backscattering light analysis in a microfluidic channel Available techniques for RBC aggregation often adopt a rotational Couette-flow using a bob-and-cup system for disaggregating RBCs, which causes the system to be complex and expensive A disposable microfluidic channel and vibration generating mechanism were used in the proposed new detection system for RBC aggregation Prior to measurement, RBC aggregates in a blood sample were completely disaggregated by the application of vibration-induced shear With the present apparatus, the aggregation indexes of RBCs can be measured easily with small quantities of a blood sample The measurements with the present aggregometer were compared with those of LORCA and the results showed a strong correlation between them The aggregability of the defibrinogenated blood RBCs is markedly lower than that of the normal RBCs The noble feature of this design is the vibration-induced disaggregation mechanism, which can incorporate the disposable element that holds the blood sample     

分布式无线土壤电导率测量装置的设计

采用电流电压四端法设计一种多点无线传输的土壤电导率测量装置.硬件部分采用TDR-4传感器的四针微型探头可减小对溶质运移的扰动,且可高密度分布在土壤中,系统连接多路电导率探头和8位高精度数据转换器能够实现多通道土壤电导率测量,并通过无线模块实现系统规模的扩展,采用主从式结构测量显示平台能够完成数据采集、显示与存储功能,有效解决了多点土壤电导率实时监测的一致性问题.试验结果表明:系统具有良好的稳定性,土壤电导率与含盐量呈线性变化.