微流控芯片

Abstract(#br)A new, simple method was reported to prepare PDMS membranes with micrometer size pores for microfluidic chip applications. The pores were formed by adding polystyrene and toluene into PDMS prepolymer solution prior to spin-coating and curing. The resulting PDMS membrane has a thickness of around 10\u003cce:hsp sp=\"0.25\"/\u003eμm and macropores with a diameter ranging from 1 to 2\u003cce:hsp sp=\"0.25\"/\u003eμm measured using scanning electron microscope (SEM) imaging.

Abstract(#br)We present a microfluidic chip for cell handling applications fabricated in polydimethylsiloxane (PDMS). The chip was designed to accumulate cells inside a reaction chamber where they can be manipulated under attendance of a liquid reagent (PEG–polyethylene glycol) for cell fusion. To enable the cell handling a fluid management system was developed which includes pneumatically actuated microfluidic valves integrated into the chip. Various valve geometries were simulated in ANSYS and characterized in a series of tests to identify a feasible valve concept.

Abstract(#br)A microfluidic biosensor chip with an embedded three-electrode configuration is developed for the study of the voltammetric response of a nanoelectrode array with controlled inter-electrode distance in a nanoliter-scale sample volume. The on-chip three-electrode cell consists of a 5\u003cce:hsp sp=\"0.25\"/\u003e×\u003cce:hsp sp=\"0.25\"/\u003e5 array of Au working nanoelectrodes with radii between 60 and 120\u003cce:hsp sp=\"0.25\"/\u003enm, a Cl 2 -plasma-treated Ag/AgCl reference electrode, and a Au counter electrode.

Abstract(#br)This work reports the fabrication and electrochemical characterization of the polydimethylsiloxane (PDMS) microfluidic three-electrode cell chip utilizing diamond-like carbon (DLC) films as a working electrode for amperometric biosensing applications. The DLC films are prepared by a radio-frequency plasma enhanced chemical vapor deposition (RF-PECVD) technique with CH4 as a carbon precursor gas. Raman spectroscopy is employed to characterize the film structures.

Abstract(#br)This work demonstrates the first study on interfacing of microfluidic chip-based chromatography to flame atomic absorption spectrometry (FAAS) for a simple and fast separation or preconcentration and subsequent determination of species. The developed low-cost polydimethylsiloxane microchip includes 12 microcolumns of conventional C18 (5\u003cce:hsp sp=\"0.25\"/\u003eμm) chromatographic particles, making the parallel chromatographic separation/preconcentration and the direct introduction of the effluent into the spectrometer possible.

Abstract(#br)We developed and examined a toxicity sensing microchip, where 200-300 cells of flagellated microbes ( Euglena gracilis ) were placed and their movements were monitored with a video camera. The microchip had two microchannels for test sample and reference flow, and the cells were confined completely in a separated closed-space (micro-aquarium). The two microchannels run aside of the micro-aquarium, and molecules of test sample permeated into the micro-aquarium from the microchannels via diffusion through porous polydimethylsiloxane (PDMS) wall.

Abstract(#br)Tumor metastasis involves the migration of cells from primary site to a distant location. Recently, it was established that cancer cells from the same tumor were heterogeneous in migratory ability. Numerous studies have demonstrated that cancer cells undergo reorientation and migration directionally under physiological electric field (EF), which has potential implications in metastasis. Microfluidic devices with channel structures of defined dimensions provide controllable microenvironments to enable real-time observation of cell migration.

Abstract(#br)Foodborne pathogen is the primary cause of foodborne disease outbreak. Given its great damage, a sensitive, simple and rapid detection method is demanded. Herein, we described a self-priming polydimethylsiloxane (PDMS)/paper hybrid microfluidic chip, termed SPH chip, with mixed-dye-loaded loop-mediated isothermal amplification (LAMP) for multiplex foodborne pathogens detection. Staphylococcus aureus (SA) and Vibrio parahaemolyticus (VP) were chosen to verify the novel method.

In this paper we present various pneumatically actuated microfluidic valves to enable user-defined fluid management within a microfluidic chip. To identify a feasible valve design, certain valve concepts are simulated in ANSYS to investigate the pressure dependent opening and closing characteristics of each design. The results are verified in a series of tests. Both the microfluidic layer and the pneumatic layer are realized by means of soft-lithographic techniques. In this way, a network of channels is fabricated in photoresist as a molding master.

摘要高效、快速的微流控芯片原型化已成为日益可能。然而，微铣削作为一种流行的微流控通道制备方法，在处理宽度小于50  μm的微通道时并没有显示出优势。本文采用一种模拟微铣削的方法- -旋转尖端微切削，实现了在几微米到几百微米宽的聚甲基丙烯酸甲酯( PMMA )上直写微通道。用压电作动器转动三面纳米压头，代替主轴转动磨机。根据旋转切削的特点，对毛刺形成和表面质量进行了优化分析，得到的微通道为无毛刺边，其底部表面粗糙度为Sa   =  19   nm。为了验证该微加工方法的有效性，设计了两种低成本的PMMA微通道微流控芯片制备工艺。一种是将制备好的PMMA片材直接键合到另一种片材上，通过紫外辅助溶剂键合，得出了通道的无毛刺边对键合浅层微通道起关键作用的结论。另一种是以制备的PMMA为模具，将微通道转移到铸型聚二甲基硅氧烷( PDMS )芯片上。最后，对制作的微交叉通道进行测试，生成微液滴，观察到微液滴的大小和生成速率可控。