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A microsystem of low-voltage-driven electrophoresis on microchip with array electrode pairs for the separation of amino acids 总被引:1,自引:0,他引:1
Yi Xu Xiaoguo Hu Jing Liang Jianxin Sun Wenwen Gu Tianming Zhao Zhiyu Wen 《Analytical and bioanalytical chemistry》2009,394(7):1947-1953
In this paper, a new approach for the separation of amino acids on the electrophoresis chip-based low-voltage-driven electrophoresis
was reported in detail. This low-voltage-driven electrophoresis process could be realized by powering directly the arrayed
electrode pairs with low direct current (DC) voltage to generate a moving electric field along the separation microchannel,
which could maintain enough electric field strength for electrophoresis. The proposed microfluidic electrophoresis chip was
bonded directly with silicon-on-insulator (SOI) substrate and polydimethylsiloxane (PDMS) cover plate at room temperature.
The microfluidic channels and the arrayed electrodes were etched on SOI wafer by silicon microelectromechanical system technology.
A specially integrated circuit was proposed to power a 30–60-V DC voltage to particular sets of these electrode pairs in a
controlled sequence such that the moving electric field could be formed, and the low-voltage-driven electrophoresis could
be realized in the microchannel. In the experiments, with 10−4 mol/L phenylalanine and lysine as analytes, the separation of amino acids on the low-voltage-driven electrophoresis microchip
was conducted by homemade integrated control circuit; a method for separating amino acids was well established. It was also
shown that the phenylalanine and lysine mixture was effectively separated in less than 7 min and with a resolution of 2.0.
To the best of our knowledge, the low-voltage-driven microchip electrophoresis device could be of potential prospective in
the fields of integrated and miniaturized biochemical analysis system.
This work was financially supported by the Chinese National Science and Technology Committee “863 PLAN” (2006AA04Z345) and
“International Cooperation Plan” (2006DFA13510) also by the Nature and Science Fund (no. 20675089) and (90307015) of Chinese
National Educational Committee. 相似文献
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This paper focused on a self-developed microfluidic array system with microfabricated capillary array electrophoresis (mu-CAE) chip for parallel chip electrophoresis of biomolecules. The microfluidic array layout consists of two common reservoirs coupled to four separation channels connected to sample injection channel on the soda-lime glass substrate. The excitation scheme for distributing a 20 mW laser beam to separation channels in an array is achieved. Under the control of program, the sample injection and separation in multichannel can be achieved through six high-voltage modules' output. A CCD camera was used to monitor electrophoretic separations simultaneously in four channels with LIF detection, and the electropherograms can be plotted directly without reconstruction by additional software. Parallel multichannel electrophoresis of series biomolecules including amino acids, proteins, and nucleic acids was performed on this system and the results showed fine reproducibility. 相似文献
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Ni Hou Yu Chen Shiyong Yu Zongliang Quan Chenhua Pan Yulin Deng Lina Geng 《Chromatographia》2014,77(19-20):1339-1346
The use of microfluidic chip-based two-dimensional separation holds great promise in the proteomics field, given its portability, simplicity, speed, efficiency, and throughput. However, inclusion of sodium dodecyl sulfate, reported to be necessary for increasing protein-resolving capability, was also accompanied by the loss of both protein conformation and biological function. Here, we describe separation of native proteins by introducing blue native gel electrophoresis into isoelectric focusing and gel electrophoresis (IEF/CGE)-coupled protein two-dimensional microfluidic chip electrophoresis. After assessing the influence of various experimental conditions, the best separation ability and reproducibility of blue native IEF/CGE (IEF/BN-CGE) chip electrophoresis achieved until now were demonstrated no matter whether with a simple simulated mixture or with a complex mixture of total Escherichia coli proteins. Finally, instead of theoretical calculations, the image analysis technique was also used for the first time to quantitatively evaluate the actual peak capacities of chip electrophoresis. According to the number of features abstracted in the electrophoresis patterns, the superiority of the IEF/BN-CGE two-dimensional microfluidic chip electrophoresis was then exhibited quantitatively. The high native protein separation performance makes this established chip electrophoresis method possible for further application in widely needed drug screening, analysis of bio-molecular function, and assays of protein–protein interactions. 相似文献
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A polymer microfluidic chip accomplishing automated sample flow and replacement without external controls and an application of the chip for bioanalytical reaction were described. All the fluidic operations in the chip were achieved by only natural capillary flow in a time-planned sequence. For the control of the capillary flow, the geometry of the channels and chambers in the chip was designed based on theoretical considerations and numerical simulations. The microfluidic chip was made by using polymer replication techniques, which were suitable for fast and cheap fabrication. The test for a biochemical analysis, employing an enzyme (HRP)-catalyzed precipitation reaction, exhibited a good performance using the developed chip. The presented microfluidic method would be applicable to biochemical lab-on-a-chips with integrated fluid replacement steps, such as affinity elution and solution exchange during biosensor signaling. 相似文献
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A new method is described for two-dimensional (2D) separations using a microfluidic chip normally employed for single dimension electrophoresis. The method employs a combination of gradient elution moving boundary electrophoresis (GEMBE) and chiral capillary zone electrophoresis (CZE). The simplicity of the first dimension GEMBE method enables its implementation in the injection channel of a conventional electrophoresis chip, simplifying the design and operation of the device. The method was used for high resolution 2D chiral separations of a mixture of amino acids considered as possible signatures of extant or extinct life for solar system exploration. The enantiomers of aspartic acid, glutamic acid, serine, alanine, and valine were all resolved as well as glycine (achiral) and several unidentified impurities, giving an estimated peak capacity of 35 for the region between valine and glycine. The results highlight the need for high peak capacity separations for chiral amino acid analysis if accurate enantiomeric ratios are to be determined. 相似文献
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We report on the fabrication and performance of a gel microfluidic chip interfaced to laser desorption/ionization (LDI) mass spectrometry with a time-of-flight mass analyzer. The chip was fabricated from poly(methylmethacrylate) with a poly(dimethyl siloxane) cover. Sodium dodecyl sulfate-polyacrylamide gel electrophoresis was performed in the channel of the microfluidic chip. After electrophoresis, the cover was removed and either the PDMS chip or the PMMA cover was mounted in a modified MALDI ion source for analysis. Ions were formed by irradiating the channel with 2.95 microm radiation from a pulsed optical parametric oscillator (OPO), which is coincident with IR absorption by N-H and O-H stretch of the gel components. No matrix was added. The microfluidic chip design allowed a decrease in the volume of material required for analysis over conventional gel slabs, thus enabling improvement in the detection limit to a pmol level, a three orders of magnitude improvement over previous studies in which desorption was achieved from an excised section of a conventional gel. 相似文献
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An experimental and numerical investigation into the use of high-resolution injection techniques to separate DNA fragments within electrophoresis microchips is presented. The principal material transport mechanisms of electrokinetic migration, fluid flow, and diffusion are considered, and several variable-volume injection methods are discussed. A detailed analysis is provided of a double-L injection technique, which employs appropriate electrokinetic manipulations to reduce sample leakage within the microchip. The leakage effect in electroosmotic flow (EOF) is investigated using a sample composed of rhodamine B and Cy3 dye. Meanwhile, the effects of sample leakage in capillary electrophoresis (CE) separation are studied by considering the separation of 100-base pairs (bp) DNA ladders and HaeIII-digested PhiX-174 DNA samples. The present experimental and simulation results indicate that the unique injection system employed in the current microfluidic chip has the ability to replicate the functions of both the conventional cross-channel and the shift-channel injection systems. Furthermore, applying the double-L injection method to these two injection systems is shown to reduce sample leakage significantly. The proposed microfluidic chip and double-L injection technique developed in this study have an exciting potential for use in high-resolution, high-throughput biochemical analysis applications and in many other applications throughout the micrototal analysis systems field. 相似文献
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A. A. Evstrapov A. L. Bulyanitsa V. E. Kurochkin A. O. Petryakov G. E. Rudnitskaya T. A. Sal'nikova Ya. I. Alekseev 《Journal of Analytical Chemistry》2004,59(6):521-527
State-of-the-art microfluidic analytical systems are briefly surveyed. Attention is focused on the use of microchip capillary electrophoresis. The main results obtained in the development of a prototype analytical system with a laser-induced fluorescence detector for electrophoresis on a glass microfluidic chip are presented. Experimental data on electroosmotic flow and the distribution of sample fluorescence intensity over the cross section of a microchannel are analyzed. A procedure for the rapid analysis of oligonucleotides on a microfluidic chip is described. 相似文献
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Isotachophoresis (ITP) has long been used alone but also as a preconcentration technique for capillary electrophoresis (CE). Unfortunately, up to now, its application is restricted to relatively strong acids and bases as either the degree of (de)protonation is too low or the water dissociation is too high, evoking zone electrophoresis. With the comprehensive ITP analysis of all 20 proteinogenic amino acids as model analytes, we, here, show that non–aqueous ITP using dimethylsulfoxide as a solvent solves this ITP shortcoming. Dimethylsulfoxide changes the pH regime of analytes and electrolytes but, more importantly, strongly reduces the proton mobility by prohibiting hydrogen bonds and thus, the so-called Zundel–Eigen–Zundel electrical conduction mechanism of flipping hydrogen bonds. The effects are demonstrated in an electrolyte system with taurine or H+ as terminator, and imidazole as leader together with strong acids such as oxalic and even trifluoroacetic acid as counterions, both impossible to use in aqueous solution. Mass spectrometric as well as capacitively coupled contactless conductivity detection (C4D) are used to follow the ITP processes. To demonstrate the preconcentration capabilities of ITP in a two-dimensional set-up, we, here, also demonstrate that our non-aqueous ITP method can be combined with capillary electrophoresis–mass spectrometry in a column-coupling system using a hybrid approach of capillaries coupled to a microfluidic interface. For this, C4D was optimized for on-chip detection with the electrodes aligned on top of a thin glass lid of the microfluidic chip. 相似文献
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A freezing technique protocol was proposed for coupling microchip electrophoresis with matrix-assisted laser desorption/ionization time-of-flight mass spectrometry(MALD1-TOF-MS).The microfluidic flow was frozen immediately after electrophoresis on microfluidic chip and the separated analyte molecules were kept in their zone pattern in the electrophoresis.Then,the frozen-chip was lyophilized and sent into TOF-MS instrument as a MALDI target,and the analyte molecules in the microfluidic channels were subjected to analysis by mass spectrometry.This approach could eliminate sample cross-contamination, providing a new interface for microchip electrophoresis and MALDI-MS. 相似文献
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Microfluidic systems are capillary networks of varying complexity fabricated originally in silicon, but nowadays in glass and polymeric substrates. Flow of liquid is mainly controlled by use of electroosmotic effects, i.e. application of electric fields, in addition to pressurized flow, i.e. application of pressure or vacuum. Because electroosmotic flow rates depend on the charge densities on the walls of capillaries, they are influenced by substrate material, fabrication processes, surface pretreatment procedures, and buffer additives. Microfluidic systems combine the properties of capillary electrophoretic systems and flow-through analytical systems, and thus biochemical analytical assays have been developed utilizing and integrating both aspects. Proteins, peptides, and nucleic acids can be separated because of their different electrophoretic mobility; detection is achieved with fluorescence detectors. For protein analysis, in particular, interfaces between microfluidic chips and mass spectrometers were developed. Further levels of integration of required sample-treatment steps were achieved by integration of protein digestion by immobilized trypsin and amplification of nucleic acids by the polymerase chain reaction. Kinetic constants of enzyme reactions were determined by adjusting different degrees of dilution of enzyme substrates or inhibitors within a single chip utilizing mainly the properties of controlled dosing and mixing liquids within a chip. For analysis of kinase reactions, however, a combination of a reaction step (enzyme with substrate and inhibitor) and a separation step (enzyme substrate and reaction product) was required. Microfluidic chips also enable separation of analytes from sample matrix constituents, which can interfere with quantitative determination, if they have different electrophoretic mobilities. In addition to analysis of nucleic acids and enzymes, immunoassays are the third group of analytical assays performed in microfluidic chips. They utilize either affinity capillary electrophoresis as a homogeneous assay format, or immobilized antigens or antibodies in heterogeneous assays with serial supply of reagents and washing solutions. 相似文献
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Microfabrication techniques used for the production of MEMS (micro electro-mechanical systems) have been successfully used to produce highly efficient microfluidic capillary electrophoresis chip systems. A limitation of this approach are the difficulties associated with the creation of the micrometer-sized structures in glass or other substrates, which currently involve specialized and expensive lithographic and etching processes. A further limitation is that hitherto most microfluidic chips are not designed for continuous introduction of a series of different samples, which limits the overall throughput of such systems. This article reviews the development of a microfluidic system for rapid CE separations, produced at a low cost of less than a dollar each, using equipment and materials readily available in the ordinary laboratory. Applications of the system, after coupling to flow-injection and/or sequential-injection sample introduction, for the determination of FITC-labeled amino acids by laser-induced fluorescence, trace metals by chemiluminescence, carbohydrates by amperometry, and inorganic and organic anions by indirect UV absorbance are exemplified to illustrate the performance and versatility of the microfluidic system. 相似文献
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Yong-Jiang Li Wen-Jia Zhang Chen-Lin Zhan Ke-Jie Chen Chun-Dong Xue Yu Wang Xiao-Ming Chen Kai-Rong Qin 《Electrophoresis》2021,42(21-22):2264-2272
Biological cells in vivo typically reside in a dynamic flowing microenvironment with extensive biomechanical and biochemical cues varying in time and space. These dynamic biomechanical and biochemical signals together act to regulate cellular behaviors and functions. Microfluidic technology is an important experimental platform for mimicking extracellular flowing microenvironment in vitro. However, most existing microfluidic chips for generating dynamic shear stress and biochemical signals require expensive, large peripheral pumps and external control systems, unsuitable for being placed inside cell incubators to conduct cell biology experiments. This study has developed a microfluidic generator of dynamic shear stress and biochemical signals based on autonomously oscillatory flow. Further, based on the lumped-parameter and distributed-parameter models of multiscale fluid dynamics, the oscillatory flow field and the concentration field of biochemical factors has been simulated at the cell culture region within the designed microfluidic chip. Using the constructed experimental system, the feasibility of the designed microfluidic chip has been validated by simulating biochemical factors with red dye. The simulation results demonstrate that dynamic shear stress and biochemical signals with adjustable period and amplitude can be generated at the cell culture chamber within the microfluidic chip. The amplitudes of dynamic shear stress and biochemical signals is proportional to the pressure difference and inversely proportional to the flow resistance, while their periods are correlated positively with the flow capacity and the flow resistance. The experimental results reveal the feasibility of the designed microfluidic chip. Conclusively, the proposed microfluidic generator based on autonomously oscillatory flow can generate dynamic shear stress and biochemical signals without peripheral pumps and external control systems. In addition to reducing the experimental cost, due to the tiny volume, it is beneficial to be integrated into cell incubators for cell biology experiments. Thus, the proposed microfluidic chip provides a novel experimental platform for cell biology investigations. 相似文献
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Microfabrication techniques used for the production of MEMS (micro electro-mechanical systems) have been successfully used
to produce highly efficient microfluidic capillary electrophoresis chip systems. A limitation of this approach are the difficulties
associated with the creation of the micrometer-sized structures in glass or other substrates, which currently involve specialized
and expensive lithographic and etching processes. A further limitation is that hitherto most microfluidic chips are not designed
for continuous introduction of a series of different samples, which limits the overall throughput of such systems. This article
reviews the development of a microfluidic system for rapid CE separations, produced at a low cost of less than a dollar each,
using equipment and materials readily available in the ordinary laboratory. Applications of the system, after coupling to
flow-injection and/or sequential-injection sample introduction, for the determination of FITC- labeled amino acids by laser-induced
fluorescence, trace metals by chemiluminescence, carbohydrates by amperometry, and inorganic and organic anions by indirect
UV absorbance are exemplified to illustrate the performance and versatility of the microfluidic system.
Received: 30 November 2000 / Revised: 13 February 2001 / Accepted: 23 February 2001 相似文献