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Processing of nanolitre liquid plugs for microfluidic cell-based assays  [cached]
Junji Fukuda, Shintaro Takahashi, Tatsuya Osaki, Naoto Mochizuki and Hiroaki Suzuki
Science and Technology of Advanced Materials , 2012,
Abstract: Plugs, i.e. droplets formed in a microchannel, may revolutionize microfluidic cell-based assays. This study describes a microdevice that handles nanolitre-scale liquid plugs for the preparation of various culture setups and subsequent cellular assays. An important feature of this mode of liquid operation is that the recirculation flow generated inside the plug promotes the rapid mixing of different solutions after plugs are merged, and it keeps cell suspensions homogeneous. Thus, serial dilutions of reagents and cell suspensions with different cell densities and cell types were rapidly performed using nanolitres of solution. Cells seeded through the plug processing grew well in the microdevice, and subsequent plug processing was used to detect the glucose consumption of cells and cellular responses to anticancer agents. The plug-based microdevice may provide a useful platform for cell-based assay systems in various fields, including fundamental cell biology and drug screening applications.
磁力旋流分选机分选大石河选厂细筛筛下物试验  [PDF]
王芝伟, 马金亭, 史佩伟, 王晓明, 魏红港
金属矿山 , 2011,
Abstract: 研制了一种主要用于磁铁矿精选的新设备——磁力旋流分选机,其特点是采用磁极螺旋排布的立式旋转磁系,分选区内筒与之逆向旋转,可形成磁力、离心力、上升水流力、重力等力的复合力场,从而高效脱除精矿中夹杂的脉石矿物和贫连生体。在实验室试验基础上,采用该设备在现场对大石河选厂细筛筛下产物进行精选半工业试验,所获指标与现场所用复合闪烁磁场精选机的生产指标相比,精矿品位提高幅度高1.22个百分点,回收率高2.01个百分点。?
Comparison of Static and Microfluidic Protease Assays Using Modified Bioluminescence Resonance Energy Transfer Chemistry  [PDF]
Nan Wu, Helen Dacres, Alisha Anderson, Stephen C. Trowell, Yonggang Zhu
PLOS ONE , 2014, DOI: 10.1371/journal.pone.0088399
Abstract: Background Fluorescence and bioluminescence resonance energy transfer (F/BRET) are two forms of F?rster resonance energy transfer, which can be used for optical transduction of biosensors. BRET has several advantages over fluorescence-based technologies because it does not require an external light source. There would be benefits in combining BRET transduction with microfluidics but the low luminance of BRET has made this challenging until now. Methodology We used a thrombin bioprobe based on a form of BRET (BRETH), which uses the BRET1 substrate, native coelenterazine, with the typical BRET2 donor and acceptor proteins linked by a thrombin target peptide. The microfluidic assay was carried out in a Y-shaped microfluidic network. The dependence of the BRETH ratio on the measurement location, flow rate and bioprobe concentration was quantified. Results were compared with the same bioprobe in a static microwell plate assay. Principal Findings The BRETH thrombin bioprobe has a lower limit of detection (LOD) than previously reported for the equivalent BRET1–based version but it is substantially brighter than the BRET2 version. The normalised BRETH ratio of the bioprobe changed 32% following complete cleavage by thrombin and 31% in the microfluidic format. The LOD for thrombin in the microfluidic format was 27 pM, compared with an LOD of 310 pM, using the same bioprobe in a static microwell assay, and two orders of magnitude lower than reported for other microfluidic chip-based protease assays. Conclusions These data demonstrate that BRET based microfluidic assays are feasible and that BRETH provides a useful test bed for optimising BRET-based microfluidics. This approach may be convenient for a wide range of applications requiring sensitive detection and/or quantification of chemical or biological analytes.
Sources of Variability in Platelet Accumulation on Type 1 Fibrillar Collagen in Microfluidic Flow Assays  [PDF]
Keith B. Neeves, Abimbola A. Onasoga, Ryan R. Hansen, Jessica J. Lilly, Diana Venckunaite, Meghan B. Sumner, Andrew T. Irish, Gary Brodsky, Marilyn J. Manco-Johnson, Jorge A. Di Paola
PLOS ONE , 2013, DOI: 10.1371/journal.pone.0054680
Abstract: Microfluidic flow assays (MFA) that measure shear dependent platelet function have potential clinical applications in the diagnosis and treatment of bleeding and thrombotic disorders. As a step towards clinical application, the objective of this study was to measure how phenotypic and genetic factors, as well as experimental conditions, affect the variability of platelet accumulation on type 1 collagen within a MFA. Whole blood was perfused over type 1 fibrillar collagen at wall shear rates of 150, 300, 750 and 1500 s?1 through four independent channels with a height of 50 μm and a width of 500 μm. The accumulation of platelets was characterized by the lag time to 1% platelet surface coverage (LagT), the rate of platelet accumulation (VPLT), and platelet surface coverage (SC). A cohort of normal donors was tested and the results were correlated to plasma von Willebrand factor (VWF) levels, platelet count, hematocrit, sex, and collagen receptors genotypes. VWF levels were the strongest determinant of platelet accumulation. VWF levels were positively correlated to VPLT and SC at all wall shear rates. A longer LagT for platelet accumulation at arterial shear rates compared to venous shear rates was attributed to the time required for plasma proteins to adsorb to collagen. There was no association between platelet accumulation and hematocrit or platelet count. Individuals with the AG genotype of the GP6 gene had lower platelet accumulation than individuals with the AA genotype at 150 s?1 and 300 s?1. Recalcified blood collected into sodium citrate and corn trypsin inhibitor (CTI) resulted in diminished platelet accumulation compared to CTI alone, suggesting that citrate irreversibly diminishes platelet function. This study the largest association study of MFA in healthy donors (n = 104) and will likely set up the basis for the determination of the normal range of platelet responses in this type of assay.
信息处理中数据表的选列与构造  [PDF]
科技进步与对策 , 2000,
Abstract: 信息系统与信息管理对信息表示形式(内容与格式)有较高的要求,即要能动态地控制,又要能简便地操作。目前的信息处理工具在这方面功能较弱,或者需管理人员用复杂的算法语言构造,这对信息的管理与使用带来不便。在设计实施信息系统中,需提供数据表选列构造的可视化操作功能。本文讨论了这方面的设计方案,并由实例说明了用PowerBuilder6.0实施的方法。信息系统信息管理实施
Microfluidic Technology in Vascular Research
A. D. van der Meer,A. A. Poot,M. H. G. Duits,J. Feijen,I. Vermes
Journal of Biomedicine and Biotechnology , 2009, DOI: 10.1155/2009/823148
Abstract: Vascular cell biology is an area of research with great biomedical relevance. Vascular dysfunction is involved in major diseases such as atherosclerosis, diabetes, and cancer. However, when studying vascular cell biology in the laboratory, it is difficult to mimic the dynamic, three-dimensional microenvironment that is found in vivo. Microfluidic technology offers unique possibilities to overcome this difficulty. In this review, an overview of the recent applications of microfluidic technology in the field of vascular biological research will be given. Examples of how microfluidics can be used to generate shear stresses, growth factor gradients, cocultures, and migration assays will be provided. The use of microfluidic devices in studying three-dimensional models of vascular tissue will be discussed. It is concluded that microfluidic technology offers great possibilities to systematically study vascular cell biology with setups that more closely mimic the in vivo situation than those that are generated with conventional methods.
Microfluidic Mixing: A Review  [PDF]
Chia-Yen Lee,Chin-Lung Chang,Yao-Nan Wang,Lung-Ming Fu
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12053263
Abstract: The aim of microfluidic mixing is to achieve a thorough and rapid mixing of multiple samples in microscale devices. In such devices, sample mixing is essentially achieved by enhancing the diffusion effect between the different species flows. Broadly speaking, microfluidic mixing schemes can be categorized as either “active”, where an external energy force is applied to perturb the sample species, or “passive”, where the contact area and contact time of the species samples are increased through specially-designed microchannel configurations. Many mixers have been proposed to facilitate this task over the past 10 years. Accordingly, this paper commences by providing a high level overview of the field of microfluidic mixing devices before describing some of the more significant proposals for active and passive mixers.
Microfluidic Technologies for Synthetic Biology  [PDF]
Parisutham Vinuselvi,Seongyong Park,Minseok Kim,Jung Min Park,Taesung Kim,Sung Kuk Lee
International Journal of Molecular Sciences , 2011, DOI: 10.3390/ijms12063576
Abstract: Microfluidic technologies have shown powerful abilities for reducing cost, time, and labor, and at the same time, for increasing accuracy, throughput, and performance in the analysis of biological and biochemical samples compared with the conventional, macroscale instruments. Synthetic biology is an emerging field of biology and has drawn much attraction due to its potential to create novel, functional biological parts and systems for special purposes. Since it is believed that the development of synthetic biology can be accelerated through the use of microfluidic technology, in this review work we focus our discussion on the latest microfluidic technologies that can provide unprecedented means in synthetic biology for dynamic profiling of gene expression/regulation with high resolution, highly sensitive on-chip and off-chip detection of metabolites, and whole-cell analysis.
Research and Development on the Photoelectric Detection Technology of Microfluidic Chip  [cached]
Zhang Rong-biao,Yang Ning,Zhao Yu-qi,Li Shu-han
Research Journal of Applied Sciences, Engineering and Technology , 2013,
Abstract: The microfluidic chip has been widely applied to areas such as medicine, bio-detection. Photoelectric detection technology is one of the most common method used in microfluidic chip detection, this study summarizes the development and application of the microfluidic chip photoelectric detection technology in recent years and analyses of the photoelectric detection of the microfluidic chip in key technologies and summarized the advantages and disadvantages of different microfluidic chip photoelectric detection technology. Photoelectric detection technology developed for high sensitivity and accuracy of professional microfluidic chip to provide a reference.
“年选”考述  [PDF]
清史研究 , 2010,
Abstract: ?本文探源"年选"说并辨析后世学者对"年选"的认识,认为应从年羹尧整个用人来认识、界定"年选";雍正帝在人事上放权给年羹尧是"年选"的必要条件,而年羹尧用人上的自专与任私是"年选"的充分条件;"年选"的终结在于雍正帝重新强调"恩威当自朕出",这是清帝实现"乾纲独揽"的一个步骤。
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