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Sample records for assemble microfluidic perfusion

  1. Simplified prototyping of perfusable polystyrene microfluidics

    Science.gov (United States)

    Tran, Reginald; Ahn, Byungwook; R. Myers, David; Qiu, Yongzhi; Sakurai, Yumiko; Moot, Robert; Mihevc, Emma; Trent Spencer, H.; Doering, Christopher; A. Lam, Wilbur

    2014-01-01

    Cell culture in microfluidic systems has primarily been conducted in devices comprised of polydimethylsiloxane (PDMS) or other elastomers. As polystyrene (PS) is the most characterized and commonly used substrate material for cell culture, microfluidic cell culture would ideally be conducted in PS-based microsystems that also enable tight control of perfusion and hydrodynamic conditions, which are especially important for culture of vascular cell types. Here, we report a simple method to prototype perfusable PS microfluidics for endothelial cell culture under flow that can be fabricated using standard lithography and wet laboratory equipment to enable stable perfusion at shear stresses up to 300 dyn/cm2 and pumping pressures up to 26 kPa for at least 100 h. This technique can also be extended to fabricate perfusable hybrid PS-PDMS microfluidics of which one application is for increased efficiency of viral transduction in non-adherent suspension cells by leveraging the high surface area to volume ratio of microfluidics and adhesion molecules that are optimized for PS substrates. These biologically compatible microfluidic devices can be made more accessible to biological-based laboratories through the outsourcing of lithography to various available microfluidic foundries. PMID:25379106

  2. Self-assembly via microfluidics

    OpenAIRE

    Wang, Lei; Sánchez, Samuel

    2015-01-01

    The self-assembly of amphiphilic building blocks has attracted extensive interest in myriad fields in recent years, due to their great potential in the nanoscale design of functional hybrid materials. Microfluidic techniques provide an intriguing method to control kinetic aspects of the self-assembly of molecular amphiphiles by the facile adjustment of the hydrodynamics of the fluids. Up to now, there have been several reports about one-step direct self-assembly of different building blocks w...

  3. Uniform yeast cell assembly via microfluidics

    OpenAIRE

    Chang, Ya-Wen; He, Peng; Marquez, Samantha M.; Cheng, Zhengdong

    2012-01-01

    This paper reports the use of microfluidic approaches for the fabrication of yeastosomes (yeast-celloidosomes) based on self-assembly of yeast cells onto liquid-solid or liquid-gas interfaces. Precise control over fluidic flows in droplet- and bubble-forming microfluidic devices allows production of monodispersed, size-selected templates. The general strategy to organize and assemble living cells is to tune electrostatic attractions between the template (gel or gas core) and the cells via sur...

  4. Uniform yeast cell assembly via microfluidics.

    Science.gov (United States)

    Chang, Ya-Wen; He, Peng; Marquez, Samantha M; Cheng, Zhengdong

    2012-06-01

    This paper reports the use of microfluidic approaches for the fabrication of yeastosomes (yeast-celloidosomes) based on self-assembly of yeast cells onto liquid-solid or liquid-gas interfaces. Precise control over fluidic flows in droplet- and bubble-forming microfluidic devices allows production of monodispersed, size-selected templates. The general strategy to organize and assemble living cells is to tune electrostatic attractions between the template (gel or gas core) and the cells via surface charging. Layer-by-Layer (LbL) polyelectrolyte deposition was employed to invert or enhance charges of solid surfaces. We demonstrated the ability to produce high-quality, monolayer-shelled yeastosome structures under proper conditions when sufficient electrostatic driving forces are present. The combination of microfluidic fabrication with cell self-assembly enables a versatile platform for designing synthetic hierarchy bio-structures. PMID:22655026

  5. Microfluidic perfusion for regulating diffusible signaling in stem cells.

    Directory of Open Access Journals (Sweden)

    Katarina Blagovic

    -dependent and -independent pathways. Overall, by uncovering autocrine\\paracrine processes previously hidden in conventional culture systems, our results establish microfluidic perfusion as a technique to study and manipulate diffusible signaling in cell systems.

  6. Microfluidic perfusion systems for secretion fingerprint analysis of pancreatic islets: applications, challenges and opportunities.

    Science.gov (United States)

    Castiello, F Rafael; Heileman, Khalil; Tabrizian, Maryam

    2016-02-01

    A secretome signature is a heterogeneous profile of secretions present in a single cell type. From the secretome signature a smaller panel of proteins, namely a secretion fingerprint, can be chosen to feasibly monitor specific cellular activity. Based on a thorough appraisal of the literature, this review explores the possibility of defining and using a secretion fingerprint to gauge the functionality of pancreatic islets of Langerhans. It covers the state of the art regarding microfluidic perfusion systems used in pancreatic islet research. Candidate analytical tools to be integrated within microfluidic perfusion systems for dynamic secretory fingerprint monitoring were identified. These analytical tools include patch clamp, amperometry/voltametry, impedance spectroscopy, field effect transistors and surface plasmon resonance. Coupled with these tools, microfluidic devices can ultimately find applications in determining islet quality for transplantation, islet regeneration and drug screening of therapeutic agents for the treatment of diabetes. PMID:26732665

  7. Self-assembled magnetic bead chains for sensitivity enhancement of microfluidic electrochemical biosensor platforms.

    Science.gov (United States)

    Armbrecht, L; Dincer, C; Kling, A; Horak, J; Kieninger, J; Urban, G

    2015-11-21

    In this paper, we present a novel approach to enhance the sensitivity of microfluidic biosensor platforms with self-assembled magnetic bead chains. An adjustable, more than 5-fold sensitivity enhancement is achieved by introducing a magnetic field gradient along a microfluidic channel by means of a soft-magnetic lattice with a 350 μm spacing. The alternating magnetic field induces the self-assembly of the magnetic beads in chains or clusters and thus improves the perfusion and active contact between the analyte and the beads. The soft-magnetic lattices can be applied independent of the channel geometry or chip material to any microfluidic biosensing platform. At the same time, the bead-based approach achieves chip reusability and shortened measurement times. The bead chain properties and the maximum flow velocity for bead retention were validated by optical microscopy in a glass capillary. The magnetic actuation system was successfully validated with a biotin-streptavidin model assay on a low-cost electrochemical microfluidic chip, fabricated by dry-film photoresist technology (DFR). Labelling with glucose oxidase (GOx) permits rapid electrochemical detection of enzymatically produced H2O2. PMID:26394820

  8. Optimal homogenization of perfusion flows in microfluidic bio-reactors; a numerical study

    CERN Document Server

    Okkels, Fridolin; Bruus, Henrik

    2009-01-01

    To ensure homogeneous conditions within the complete area of perfused microfluidic bio-reactors, we develop a general design of a continuously feed bio-reactor with uniform perfusion flow. This is achieved by introducing a specific type of perfusion inlet to the reaction area. The geometry of these inlets are found using the methods of topology optimization and shape optimization. The results are compared with two different analytic models, from which a general parametric description of the design is obtained and tested numerically. Such a parametric description will generally be beneficial for the design of a broad range of microfluidic bioreactors used for e.g. cell culturing and analysis, and in feeding bio-arrays.

  9. Optimal Homogenization of Perfusion Flows in Microfluidic Bio-Reactors: A Numerical Study

    DEFF Research Database (Denmark)

    Okkels, Fridolin; Dufva, Martin; Bruus, Henrik

    2011-01-01

    In recent years, the interest in small-scale bio-reactors has increased dramatically. To ensure homogeneous conditions within the complete area of perfused microfluidic bio-reactors, we develop a general design of a continually feed bio-reactor with uniform perfusion flow. This is achieved...... by introducing a specific type of perfusion inlet to the reaction area. The geometry of these inlets are found using the methods of topology optimization and shape optimization. The results are compared with two different analytic models, from which a general parametric description of the design is obtained...... and tested numerically. Such a parametric description will generally be beneficial for the design of a broad range of microfluidic bioreactors used for, e. g., cell culturing and analysis and in feeding bio-arrays....

  10. Perfused drop microfluidic device for brain slice culture-based drug discovery.

    Science.gov (United States)

    Liu, Jing; Pan, Liping; Cheng, Xuanhong; Berdichevsky, Yevgeny

    2016-06-01

    Living slices of brain tissue are widely used to model brain processes in vitro. In addition to basic neurophysiology studies, brain slices are also extensively used for pharmacology, toxicology, and drug discovery research. In these experiments, high parallelism and throughput are critical. Capability to conduct long-term electrical recording experiments may also be necessary to address disease processes that require protein synthesis and neural circuit rewiring. We developed a novel perfused drop microfluidic device for use with long term cultures of brain slices (organotypic cultures). Slices of hippocampus were placed into wells cut in polydimethylsiloxane (PDMS) film. Fluid level in the wells was hydrostatically controlled such that a drop was formed around each slice. The drops were continuously perfused with culture medium through microchannels. We found that viable organotypic hippocampal slice cultures could be maintained for at least 9 days in vitro. PDMS microfluidic network could be readily integrated with substrate-printed microelectrodes for parallel electrical recordings of multiple perfused organotypic cultures on a single MEA chip. We expect that this highly scalable perfused drop microfluidic device will facilitate high-throughput drug discovery and toxicology. PMID:27194028

  11. Development of an Integrated Microfluidic Perfusion Cell Culture System for Real-Time Microscopic Observation of Biological Cells

    OpenAIRE

    Chih-Chin Oh-Yang; Min-Hsien Wu; Jr-Lung Lin; Shih-Siou Wang

    2011-01-01

    This study reports an integrated microfluidic perfusion cell culture system consisting of a microfluidic cell culture chip, and an indium tin oxide (ITO) glass-based microheater chip for micro-scale perfusion cell culture, and its real-time microscopic observation. The system features in maintaining both uniform, and stable chemical or thermal environments, and providing a backflow-free medium pumping, and a precise thermal control functions. In this work, the performance of the medium pumpin...

  12. Blood Perfusion in Microfluidic Models of Pulmonary Capillary Networks: Role of Geometry and Hematocrit

    Science.gov (United States)

    Stauber, Hagit; Waisman, Dan; Sznitman, Josue; Technion-IIT Team; Department of Neonatology Carmel Medical Center; Faculty of Medicine-Technion IIT Collaboration

    2015-11-01

    Microfluidic platforms are increasingly used to study blood microflows at true physiological scale due to their ability to overcome manufacturing obstacle of complex anatomical morphologies, such as the organ-specific architectures of the microcirculation. In the present work, we utilize microfluidic platforms to devise in vitro models of the underlying pulmonary capillary networks (PCN), where capillary lengths and diameters are similar to the size of RBCs (~ 5-10 μm). To better understand flow characteristics and dispersion of red blood cells (RBCs) in PCNs, we have designed microfluidic models of alveolar capillary beds inspired by the seminal ``sheet flow'' model of Fung and Sobin (1969). Our microfluidic PCNs feature confined arrays of staggered pillars with diameters of ~ 5,7 and 10 μm, mimicking the dense structure of pulmonary capillary meshes. The devices are perfused with suspensions of RBCs at varying hematocrit levels under different flow rates. Whole-field velocity patterns using micro-PIV and single-cell tracking using PTV are obtained with fluorescently-labelled RBCs and discussed. Our experiments deliver a real-scale quantitative description of RBC perfusion characteristics across the pulmonary capillary microcirculation.

  13. Microfluidic Induced Controllable Microdroplets Assembly in Confined Channels

    Directory of Open Access Journals (Sweden)

    Juan Wang

    2015-09-01

    Full Text Available We report on the microfluidic induced monodispersed microdroplet generation and assembly in confined microchannels. Two and three dimensional close-packed droplet lattices were obtained in microfluidic devices by adjusting the channel geometry, the fluidic flow rates and the monodispersed droplet size. The droplet packing was mainly caused by the volumetric effect and capillarity in confined microchannels. Polymerizable fluids were also investigated to demonstrate the effect of fluidic properties on the microdroplet generation and assembly, which could find interesting applications in the future. This approach would be helpful to fundamentally understand the mechanism of self-assembly process of particles in confined microstructures, and practically be applied in sensing and energy storage devices.

  14. A polystyrene-based microfluidic device with three-dimensional interconnected microporous walls for perfusion cell culture

    Science.gov (United States)

    Chan, Chung Yu; Goral, Vasiliy N.; DeRosa, Michael E.; Huang, Tony Jun

    2014-01-01

    In this article, we present a simple, rapid prototyped polystyrene-based microfluidic device with three-dimensional (3D) interconnected microporous walls for long term perfusion cell culture. Patterned 3D interconnected microporous structures were created by a chemical treatment together with a protective mask and the native hydrophobic nature of the microporous structures were selectively made hydrophilic using oxygen plasma treatment together with a protective mask. Using this polystyrene-based cell culture microfluidic device, we successfully demonstrated the support of four days perfusion cell culture of hepatocytes (C3A cells). PMID:25379110

  15. Integrated Electroosmotic Perfusion of Tissue with Online Microfluidic Analysis to Track the Metabolism of Cystamine, Pantethine and Coenzyme A

    OpenAIRE

    Wu, Juanfang; Sandberg, Mats; Weber, Stephen G.

    2013-01-01

    We have developed an approach that integrates electroosmotic perfusion of tissue with a substrate-containing solution and online microfluidic analysis of products, in this case thiols. Using this approach we have tracked the metabolism of cystamine, pantethine and CoA in the extracellular space of organotypic hippocampal slice cultures (OHSCs). Currently, little is known about coenzyme A (CoA) biodegradation and even less is known about the regulation and kinetic characteristics for this sequ...

  16. Vapor deposition of cross-linked fluoropolymer barrier coatings onto pre-assembled microfluidic devices.

    Science.gov (United States)

    Riche, Carson T; Marin, Brandon C; Malmstadt, Noah; Gupta, Malancha

    2011-09-21

    The interior surfaces of pre-assembled poly(dimethylsiloxane) (PDMS) microfluidic devices were modified with a cross-linked fluoropolymer barrier coating that significantly increased the chemical compatibility of the devices. PMID:21850298

  17. Control of perfusable microvascular network morphology using a multiculture microfluidic system.

    Science.gov (United States)

    Whisler, Jordan A; Chen, Michelle B; Kamm, Roger D

    2014-07-01

    The mechanical and biochemical microenvironment influences the morphological characteristics of microvascular networks (MVNs) formed by endothelial cells (ECs) undergoing the process of vasculogenesis. The objective of this study was to quantify the role of individual factors in determining key network parameters in an effort to construct a set of design principles for engineering vascular networks with prescribed morphologies. To achieve this goal, we developed a multiculture microfluidic platform enabling precise control over paracrine signaling, cell-seeding densities, and hydrogel mechanical properties. Human umbilical vein endothelial cells (HUVECs) were seeded in fibrin gels and cultured alongside human lung fibroblasts (HLFs). The engineered vessels formed in our device contained patent, perfusable lumens. Communication between the two cell types was found to be critical in avoiding network regression and maintaining stable morphology beyond 4 days. The number of branches, average branch length, percent vascularized area, and average vessel diameter were found to depend uniquely on several input parameters. Importantly, multiple inputs were found to control any given output network parameter. For example, the vessel diameter can be decreased either by applying angiogenic growth factors--vascular endothelial growth factor (VEGF) and sphingosine-1-phsophate (S1P)--or by increasing the fibrinogen concentration in the hydrogel. These findings introduce control into the design of MVNs with specified morphological properties for tissue-specific engineering applications. PMID:24151838

  18. Development of an Integrated Microfluidic Perfusion Cell Culture System for Real-Time Microscopic Observation of Biological Cells

    Directory of Open Access Journals (Sweden)

    Chih-Chin Oh-Yang

    2011-08-01

    Full Text Available This study reports an integrated microfluidic perfusion cell culture system consisting of a microfluidic cell culture chip, and an indium tin oxide (ITO glass-based microheater chip for micro-scale perfusion cell culture, and its real-time microscopic observation. The system features in maintaining both uniform, and stable chemical or thermal environments, and providing a backflow-free medium pumping, and a precise thermal control functions. In this work, the performance of the medium pumping scheme, and the ITO glass microheater were experimentally evaluated. Results show that the medium delivery mechanism was able to provide pumping rates ranging from 15.4 to 120.0 μL·min−1. In addition, numerical simulation and experimental evaluation were conducted to verify that the ITO glass microheater was capable of providing a spatially uniform thermal environment, and precise temperature control with a mild variation of ±0.3 °C. Furthermore, a perfusion cell culture was successfully demonstrated, showing the cultured cells were kept at high cell viability of 95 ± 2%. In the process, the cultured chondrocytes can be clearly visualized microscopically. As a whole, the proposed cell culture system has paved an alternative route to carry out real-time microscopic observation of biological cells in a simple, user-friendly, and low cost manner.

  19. Microfluidic techniques for the study of self-assembly of soft materials

    Science.gov (United States)

    Aguade Cabanas, Rafael

    This research is an approach to the study of soft condensed matter where the use of new microfluidic technology plays a central role. Often, in the study of soft matter, the sample volumes are very small, of the order of nanoliters. Therefore to quantitatively measure the equilibrium or non-equilibrium phase behavior requires microfluidics. Presented here are (1) a new way of producing aqueous drops of order 1 nl volume, in oil, (2) a new fabrication protocol to make microfluidic devices out of epoxy glue, and (3) a new microfluidic flow cell to study colloidal self-assembly. Also presented here is a new kind of colloidal particle, consisting of single strands of DNA linked to the surface of fd virus. This new particle may serve as a liquid crystalline colloid with a temperature dependent tunable potential. The fabrication process is the first step in the study of the self-assembly of rod-like particles with a temperature dependent potential.

  20. Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays

    OpenAIRE

    Saliba, Antoine-Emmanuel; Saias, Laure; Psychari, Eleni; Minc, Nicolas; Simon, Damien; Bidard, François-Clément; Mathiot, Claire; Pierga, Jean-Yves; Fraisier, Vincent; Salamero, Jean; Saada, Véronique; Farace, Françoise; Vielh, Philippe; Malaquin, Laurent; Viovy, Jean-Louis

    2010-01-01

    We propose a unique method for cell sorting, “Ephesia,” using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the application of a well controlled, flow-activated interaction between cells and beads, and those of immunomagnetic sorting, notably the use of batch-prepared, well characterized antibody-bearing beads. On c...

  1. Three-dimensional paper microfluidic devices assembled using the principles of origami.

    Science.gov (United States)

    Liu, Hong; Crooks, Richard M

    2011-11-01

    We report a method, based on the principles of origami (paper folding), for fabricating three-dimensional (3-D) paper microfluidic devices. The entire 3-D device is fabricated on a single sheet of flat paper in a single photolithographic step. It is assembled by simply folding the paper by hand. Following analysis, the device can be unfolded to reveal each layer. The applicability of the device to chemical analysis is demonstrated by colorimetric and fluorescence assays using multilayer microfluidic networks.

  2. Microfluidic assembly kit based on laser-cut building blocks for education and fast prototyping.

    Science.gov (United States)

    Gerber, Lukas C; Kim, Honesty; Riedel-Kruse, Ingmar H

    2015-11-01

    Here, we present an inexpensive rapid-prototyping method that allows researchers and children to quickly assemble multi-layered microfluidic devices from easily pre-fabricated building blocks. We developed low-cost (building block pieces and double-sided tape that allow users to generate water droplets in oil, capture living cells, and conduct basic phototaxis experiments. We developed and tested a 90-min lesson plan with children aged 12-14 yr and provide here the instructions for teachers to replicate these experiments and lessons. All parts of the kit are easy to make or order. We propose to use such easy to fabricate kits in labs with no access to current microfluidic tools as well as in classroom environments to get exposure to the powerful techniques of microfluidics. PMID:26634013

  3. Stepwise Synthesis of Giant Unilamellar Vesicles on a Microfluidic Assembly Line

    OpenAIRE

    Matosevic, Sandro; Brian M Paegel

    2011-01-01

    Among the molecular milieu of the cell, the membrane bilayer stands out as a complex and elusive synthetic target. We report a microfluidic assembly line that produces uniform cellular compartments from droplet, lipid, and oil/water interface starting materials. Droplets form in a lipid-containing oil flow and travel to a junction where the confluence of oil and extracellular aqueous media establishes a flow-patterned interface that is both stable and reproducible. A triangular post mediates ...

  4. Control of Perfusable Microvascular Network Morphology Using a Multiculture Microfluidic System

    OpenAIRE

    Whisler, Jordan A.; Chen, Michelle B.; Kamm, Roger D.

    2012-01-01

    The mechanical and biochemical microenvironment influences the morphological characteristics of microvascular networks (MVNs) formed by endothelial cells (ECs) undergoing the process of vasculogenesis. The objective of this study was to quantify the role of individual factors in determining key network parameters in an effort to construct a set of design principles for engineering vascular networks with prescribed morphologies. To achieve this goal, we developed a multiculture microfluidic pl...

  5. Microfluidically supported biochip design for culture of endothelial cell layers with improved perfusion conditions.

    Science.gov (United States)

    Raasch, Martin; Rennert, Knut; Jahn, Tobias; Peters, Sven; Henkel, Thomas; Huber, Otmar; Schulz, Ingo; Becker, Holger; Lorkowski, Stefan; Funke, Harald; Mosig, Alexander

    2015-01-01

    Hemodynamic forces generated by the blood flow are of central importance for the function of endothelial cells (ECs), which form a biologically active cellular monolayer in blood vessels and serve as a selective barrier for macromolecular permeability. Mechanical stimulation of the endothelial monolayer induces morphological remodeling in its cytoskeleton. For in vitro studies on EC biology culture devices are desirable that simulate conditions of flow in blood vessels and allow flow-based adhesion/permeability assays under optimal perfusion conditions. With this aim we designed a biochip comprising a perfusable membrane that serves as cell culture platform multi-organ-tissue-flow (MOTiF biochip). This biochip allows an effective supply with nutrition medium, discharge of catabolic cell metabolites and defined application of shear stress to ECs under laminar flow conditions. To characterize EC layers cultured in the MOTiF biochip we investigated cell viability, expression of EC marker proteins and cell adhesion molecules of ECs dynamically cultured under low and high shear stress, and compared them with an endothelial culture in established two-dimensionally perfused flow chambers and under static conditions. We show that ECs cultured in the MOTiF biochip form a tight EC monolayer with increased cellular density, enhanced cell layer thickness, presumably as the result of a rapid and effective adaption to shear stress by remodeling of the cytoskeleton. Moreover, endothelial layers in the MOTiF biochip express higher amounts of EC marker proteins von-Willebrand-factor and PECAM-1. EC layers were highly responsive to stimulation with TNFα as detected at the level of ICAM-1, VCAM-1 and E-selectin expression and modulation of endothelial permeability in response to TNFα/IFNγ treatment under flow conditions. Compared to static and two-dimensionally perfused cell culture condition we consider MOTiF biochips as a valuable tool for studying EC biology in vitro under

  6. Inertially Stabilized Microfluidic Crystals: Self-assembly and Spatial Frequency Tuning

    Science.gov (United States)

    Lee, Wonhee; Amini, Hamed; Stone, Howard; di Carlo, Dino

    2010-11-01

    Dynamic self-assembly can be found over a wide range of scales originating from different fundamental opposing forces. By taking advantage of inertial effects we demonstrate controllable self-assembling particle systems at the microscale. Inertially focused particles in confined high-speed microfluidic channel flows dynamically self-assemble into uniformly spaced lattices through purely hydrodynamic interactions with no external force fields. Focusing on the dynamics of the particle-particle interactions reveals a mechanism for the dynamic self-assembly process; inertial lift forces and a parabolic flow field act together to stabilize interparticle spacings that otherwise would diverge to infinity due to viscous wakes. The interplay of the repulsive viscous interaction and inertial lift also allow us to design and implement microfluidic structures that irreversibly change interparticle spacing, similar to a low-pass filter. Although often not considered at the microscale, nonlinearity due to inertia can provide a platform for high-throughput passive control of particle positions in all directions, which will be useful for applications in flow cytometry, tissue engineering, and synthesis of metamaterials.

  7. Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays

    Science.gov (United States)

    Saliba, Antoine-Emmanuel; Saias, Laure; Psychari, Eleni; Minc, Nicolas; Simon, Damien; Bidard, François-Clément; Mathiot, Claire; Pierga, Jean-Yves; Fraisier, Vincent; Salamero, Jean; Saada, Véronique; Farace, Françoise; Vielh, Philippe; Malaquin, Laurent; Viovy, Jean-Louis

    2010-01-01

    We propose a unique method for cell sorting, “Ephesia,” using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the application of a well controlled, flow-activated interaction between cells and beads, and those of immunomagnetic sorting, notably the use of batch-prepared, well characterized antibody-bearing beads. On cell lines mixtures, we demonstrated a capture yield better than 94%, and the possibility to cultivate in situ the captured cells. A second series of experiments involved clinical samples—blood, pleural effusion, and fine needle aspirates— issued from healthy donors and patients with B-cell hematological malignant tumors (leukemia and lymphoma). The immunophenotype and morphology of B-lymphocytes were analyzed directly in the microfluidic chamber, and compared with conventional flow cytometry and visual cytology data, in a blind test. Immunophenotyping results using Ephesia were fully consistent with those obtained by flow cytometry. We obtained in situ high resolution confocal three-dimensional images of the cell nuclei, showing intranuclear details consistent with conventional cytological staining. Ephesia thus provides a powerful approach to cell capture and typing allowing fully automated high resolution and quantitative immunophenotyping and morphological analysis. It requires at least 10 times smaller sample volume and cell numbers than cytometry, potentially increasing the range of indications and the success rate of microbiopsy-based diagnosis, and reducing analysis time and cost. PMID:20679245

  8. Microfluidic sorting and multimodal typing of cancer cells in self-assembled magnetic arrays.

    Science.gov (United States)

    Saliba, Antoine-Emmanuel; Saias, Laure; Psychari, Eleni; Minc, Nicolas; Simon, Damien; Bidard, François-Clément; Mathiot, Claire; Pierga, Jean-Yves; Fraisier, Vincent; Salamero, Jean; Saada, Véronique; Farace, Françoise; Vielh, Philippe; Malaquin, Laurent; Viovy, Jean-Louis

    2010-08-17

    We propose a unique method for cell sorting, "Ephesia," using columns of biofunctionalized superparamagnetic beads self-assembled in a microfluidic channel onto an array of magnetic traps prepared by microcontact printing. It combines the advantages of microfluidic cell sorting, notably the application of a well controlled, flow-activated interaction between cells and beads, and those of immunomagnetic sorting, notably the use of batch-prepared, well characterized antibody-bearing beads. On cell lines mixtures, we demonstrated a capture yield better than 94%, and the possibility to cultivate in situ the captured cells. A second series of experiments involved clinical samples--blood, pleural effusion, and fine needle aspirates--issued from healthy donors and patients with B-cell hematological malignant tumors (leukemia and lymphoma). The immunophenotype and morphology of B-lymphocytes were analyzed directly in the microfluidic chamber, and compared with conventional flow cytometry and visual cytology data, in a blind test. Immunophenotyping results using Ephesia were fully consistent with those obtained by flow cytometry. We obtained in situ high resolution confocal three-dimensional images of the cell nuclei, showing intranuclear details consistent with conventional cytological staining. Ephesia thus provides a powerful approach to cell capture and typing allowing fully automated high resolution and quantitative immunophenotyping and morphological analysis. It requires at least 10 times smaller sample volume and cell numbers than cytometry, potentially increasing the range of indications and the success rate of microbiopsy-based diagnosis, and reducing analysis time and cost. PMID:20679245

  9. Microfluidic Impedimetric Cell Regeneration Assay to Monitor the Enhanced Cytotoxic Effect of Nanomaterial Perfusion

    Directory of Open Access Journals (Sweden)

    Mario Rothbauer

    2015-11-01

    Full Text Available In the last decade, the application of nanomaterials (NMs in technical products and biomedicine has become a rapidly increasing market trend. As the safety and efficacy of NMs are of utmost importance, new methods are needed to study the dynamic interactions of NMs at the nano-biointerface. However, evaluation of NMs based on standard and static cell culture end-point detection methods does not provide information on the dynamics of living biological systems, which is crucial for the understanding of physiological responses. To bridge this technological gap, we here present a microfluidic cell culture system containing embedded impedance microsensors to continuously and non-invasively monitor the effects of NMs on adherent cells under varying flow conditions. As a model, the impact of silica NMs on the vitality and regenerative capacity of human lung cells after acute and chronic exposure scenarios was studied over an 18-h period following a four-hour NM treatment. Results of the study demonstrated that the developed system is applicable to reliably analyze the consequences of dynamic NM exposure to physiological cell barriers in both nanotoxicology and nanomedicine.

  10. Integrated electroosmotic perfusion of tissue with online microfluidic analysis to track the metabolism of cystamine, pantethine, and coenzyme A.

    Science.gov (United States)

    Wu, Juanfang; Sandberg, Mats; Weber, Stephen G

    2013-12-17

    We have developed an approach that integrates electroosmotic perfusion of tissue with a substrate-containing solution and online microfluidic analysis of products, in this case thiols. Using this approach we have tracked the metabolism of cystamine, pantethine and CoA in the extracellular space of organotypic hippocampal slice cultures (OHSCs). Currently, little is known about coenzyme A (CoA) biodegradation and even less is known about the regulation and kinetic characteristics for this sequential multienzyme reaction. We found that the steady state percentage yields of cysteamine from cystamine and pantethine during the transit through OHSCs were 91% ± 4% (SEM) and 0.01%-0.03%, respectively. The large difference in the yields of cysteamine can be used to explain the drugs' different toxicities and clinical effectiveness against cystinosis. The kinetic parameters of the enzyme reaction catalyzed by the ectoenzyme pantetheinase are KM,C/α = 4.4 ± 1.1 mM and Vmax,C = 29 ± 3 nM/s, where α is the percentage yield of pantethine to pantetheine through disulfide exchange. We estimate that the percentage yield of pantethine to pantetheine through disulfide exchange is approximately 0.5%. Based on the formation rate of cysteamine in the OHSCs, we obtained the overall apparent Michaelis constant and maximum reaction rate for sequential, extracellular CoA degradation in an in situ environment, which are K'M = 16 ± 4 μM, V'max = 7.1 ± 0.5 nM/s. Kinetic parameters obtained in situ, although difficult to measure, are better representations of the biochemical flux in the living organism than those from isolated enzymes in vitro. PMID:24215585

  11. Manipulating fluids: Advances in micro-fluidics, opto-fluidics and fluidic self assembly

    Science.gov (United States)

    Vyawahare, Saurabh

    This dissertation describes work in three inter-related areas---micro-fluidics, opto-fluidics and fluidic self-assembly. Micro-fluidics has gotten a boost in recent years with the development of multilayered elastomeric devices made of poly (dimethylsiloxane) (PDMS), allowing active elements like valves and pumps. However, while PDMS has many advantages, it is not resistant to organic solvents. New materials and/or new designs are needed for solvent resistance. I describe how novel fluorinated elastomers can replace PDMS when combined with the three dimensional (3-D) solid printing. I also show how another 3-D fabrication method, multilayer photo-lithography, allows for fabrication of devices integrating filters. In general, 3-D fabrications allow new kinds of micro-fluidic devices to be made that would be impossible to emulate with two dimensional chips. In opto-fluidics, I describe a number of experiments with quantum dots both inside and outside chips. Inside chips, I manipulate quantum dots using hydrodynamic focusing to pattern fine lines, like a barcode. Outside chips, I describe our attempts to create quantum dot composites with micro-spheres. I also show how evaporated gold films and chemical passivation can then be used to enhance the emission of quantum dots. Finally, within fluids, self assembly is an attractive way to manipulate materials, and I provide two examples: first, a DNA-based energy transfer molecule that relies on quantum mechanics and self-assembles inside fluids. This kind of molecular photonics mimics parts of the photosynthetic apparatus of plants and bacteria. The second example of self-assembly in fluids describes a new phenomena---the surface tension mediated self assembly of particles like quantum dots and micro-spheres into fine lines. This self assembly by capillary flows can be combined with photo-lithography, and is expected to find use in future nano- and micro-fabrication schemes. In conclusion, advances in fludics, integrating

  12. Polymeric nanoparticles assembled with microfluidics for drug delivery across the blood-brain barrier

    Science.gov (United States)

    Tavares, M. R.; de Menezes, L. R.; do Nascimento, D. F.; Souza, D. H. S.; Reynaud, F.; Marques, M. F. V.; Tavares, M. I. B.

    2016-07-01

    The blood-brain barrier (BBB) is a challenge in the treatment of some diseases, since it prevents many drugs from reaching therapeutic concentrations in the brain. In this context, there is a growing interest in nanoparticles for drug delivery, since they are able to cross this barrier and target the brain. The use of polymeric materials in the development of these nanoparticles has been extensively studied. It has already been demonstrated that these nanosystems have the ability to cross the BBB, which allows effective drug release into the brain. Biodegradable polymers provide a great advantage in the development of nanosystems, but modifications of the nanoparticles' surface is essential. The traditional batch methods lack precise control over the processes of nucleation and growth, resulting in poor control over final properties of the nanoparticles. Therefore, microfluidics could be used to achieve a better production environment for the fabrication of nano- structured drug delivery systems. This study provides a brief review of: the BBB, the polymeric nanoparticles with the ability to overcome the barrier, the properties of the most used polymeric matrices, and the nanostructured drug delivery systems assembled with microfluidics.

  13. Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles.

    Science.gov (United States)

    Wei, Xi; Syed, Abeer; Mao, Pan; Han, Jongyoon; Song, Yong-Ak

    2016-03-13

    Polydimethylsiloxane (PDMS) is the prevailing building material to make microfluidic devices due to its ease of molding and bonding as well as its transparency. Due to the softness of the PDMS material, however, it is challenging to use PDMS for building nanochannels. The channels tend to collapse easily during plasma bonding. In this paper, we present an evaporation-driven self-assembly method of silica colloidal nanoparticles to create nanofluidic junctions with sub-50 nm pores between two microchannels. The pore size as well as the surface charge of the nanofluidic junction is tunable simply by changing the colloidal silica bead size and surface functionalization outside of the assembled microfluidic device in a vial before the self-assembly process. Using the self-assembly of nanoparticles with a bead size of 300 nm, 500 nm, and 900 nm, it was possible to fabricate a porous membrane with a pore size of ~45 nm, ~75 nm and ~135 nm, respectively. Under electrical potential, this nanoporous membrane initiated ion concentration polarization (ICP) acting as a cation-selective membrane to concentrate DNA by ~1,700 times within 15 min. This non-lithographic nanofabrication process opens up a new opportunity to build a tunable nanofluidic junction for the study of nanoscale transport processes of ions and molecules inside a PDMS microfluidic chip.

  14. Creating Sub-50 Nm Nanofluidic Junctions in PDMS Microfluidic Chip via Self-Assembly Process of Colloidal Particles.

    Science.gov (United States)

    Wei, Xi; Syed, Abeer; Mao, Pan; Han, Jongyoon; Song, Yong-Ak

    2016-01-01

    Polydimethylsiloxane (PDMS) is the prevailing building material to make microfluidic devices due to its ease of molding and bonding as well as its transparency. Due to the softness of the PDMS material, however, it is challenging to use PDMS for building nanochannels. The channels tend to collapse easily during plasma bonding. In this paper, we present an evaporation-driven self-assembly method of silica colloidal nanoparticles to create nanofluidic junctions with sub-50 nm pores between two microchannels. The pore size as well as the surface charge of the nanofluidic junction is tunable simply by changing the colloidal silica bead size and surface functionalization outside of the assembled microfluidic device in a vial before the self-assembly process. Using the self-assembly of nanoparticles with a bead size of 300 nm, 500 nm, and 900 nm, it was possible to fabricate a porous membrane with a pore size of ~45 nm, ~75 nm and ~135 nm, respectively. Under electrical potential, this nanoporous membrane initiated ion concentration polarization (ICP) acting as a cation-selective membrane to concentrate DNA by ~1,700 times within 15 min. This non-lithographic nanofabrication process opens up a new opportunity to build a tunable nanofluidic junction for the study of nanoscale transport processes of ions and molecules inside a PDMS microfluidic chip. PMID:27023724

  15. Microfluidics-mediated assembly of functional nanoparticles for cancer-related pharmaceutical applications

    Science.gov (United States)

    Feng, Qiang; Sun, Jiashu; Jiang, Xingyu

    2016-06-01

    The controlled synthesis of functional nanoparticles with tunable structures and properties has been extensively investigated for cancer treatment and diagnosis. Among a variety of methods for fabrication of nanoparticles, microfluidics-based synthesis enables enhanced mixing and precise fluidic modulation inside microchannels, thus allowing for the flow-mediated production of nanoparticles in a controllable manner. This review focuses on recent advances of using microfluidic devices for the synthesis of drug-loaded nanoparticles with specific characteristics (such as size, composite, surface modification, structure and rigidity) for enhanced cancer treatment and diagnosis as well as to investigate the bio-nanoparticle interaction. The discussion on microfluidics-based synthesis may shed light on the rational design of functional nanoparticles for cancer-related pharmaceutical applications.

  16. Microfluidics-assisted diffusion self-assembly: toward the control of the shape and size of pectin hydrogel microparticles.

    Science.gov (United States)

    Marquis, Mélanie; Davy, Joelle; Fang, Aiping; Renard, Denis

    2014-05-12

    We demonstrated the generation of pectin hydrogel microparticles having complex shapes either by combining the phenomenon of gelation and water diffusion-induced self-assembly in microfluidic channels (on-chip) or by the deformation of the pregelled droplets outside the channels (off-chip) at a fluid-fluid interface. We proved that by tuning the mode of pectin cross-linking (CaCl2 vs CaCO3) and the degree of shrinking (water content in the dimethyl carbonate (DMC) organic continuous phase) we can control the shape of the final particle. Sphere, doughnut, oblate ellipsoid, or mushroom-type morphologies were thus produced, demonstrating the ability to control the formation of anisotropic biopolymer-based hydrogel microparticles using microfluidics. Shape changes were explained by the redistribution of calcium ions in combination with the local Peclet number experienced by the microdroplets during the on-chip process. Moreover, during the off-chip process, the interplay between elastic and viscous forces for microdroplets entering the CaCl2-DMC interface caused deformation of the pregelled droplets to occur and therefore resulted in the formation of microparticles with a mushroom-like morphology.

  17. Ultra-Portable Smartphone Controlled Integrated Digital Microfluidic System in a 3D-Printed Modular Assembly

    Directory of Open Access Journals (Sweden)

    Mohamed Yafia

    2015-09-01

    Full Text Available Portable sensors and biomedical devices are influenced by the recent advances in microfluidics technologies, compact fabrication techniques, improved detection limits and enhanced analysis capabilities. This paper reports the development of an integrated ultraportable, low-cost, and modular digital microfluidic (DMF system and its successful integration with a smartphone used as a high-level controller and post processing station. Low power and cost effective electronic circuits are designed to generate the high voltages required for DMF operations in both open and closed configurations (from 100 to 800 V. The smartphone in turn commands a microcontroller that manipulate the voltage signals required for droplet actuation in the DMF chip and communicates wirelessly with the microcontroller via Bluetooth module. Moreover, the smartphone acts as a detection and image analysis station with an attached microscopic lens. The holder assembly is fabricated using three-dimensional (3D printing technology to facilitate rapid prototyping. The holder features a modular design that enables convenient attachment/detachment of a variety of DMF chips to/from an electrical busbar. The electrical circuits, controller and communication system are designed to minimize the power consumption in order to run the device on small lithium ion batteries. Successful controlled DMF operations and a basic colorimetric assay using the smartphone are demonstrated.

  18. Microfluidics-assisted diffusion self-assembly: toward the control of the shape and size of pectin hydrogel microparticles.

    Science.gov (United States)

    Marquis, Mélanie; Davy, Joelle; Fang, Aiping; Renard, Denis

    2014-05-12

    We demonstrated the generation of pectin hydrogel microparticles having complex shapes either by combining the phenomenon of gelation and water diffusion-induced self-assembly in microfluidic channels (on-chip) or by the deformation of the pregelled droplets outside the channels (off-chip) at a fluid-fluid interface. We proved that by tuning the mode of pectin cross-linking (CaCl2 vs CaCO3) and the degree of shrinking (water content in the dimethyl carbonate (DMC) organic continuous phase) we can control the shape of the final particle. Sphere, doughnut, oblate ellipsoid, or mushroom-type morphologies were thus produced, demonstrating the ability to control the formation of anisotropic biopolymer-based hydrogel microparticles using microfluidics. Shape changes were explained by the redistribution of calcium ions in combination with the local Peclet number experienced by the microdroplets during the on-chip process. Moreover, during the off-chip process, the interplay between elastic and viscous forces for microdroplets entering the CaCl2-DMC interface caused deformation of the pregelled droplets to occur and therefore resulted in the formation of microparticles with a mushroom-like morphology. PMID:24673589

  19. Vesicles-on-a-chip: A universal microfluidic platform for the assembly of liposomes and polymersomes.

    Science.gov (United States)

    Petit, Julien; Polenz, Ingmar; Baret, Jean-Christophe; Herminghaus, Stephan; Bäumchen, Oliver

    2016-06-01

    In this study, we present a PDMS-based microfluidic platform for the fabrication of both liposomes and polymersomes. Based on a double-emulsion template formed in flow-focusing configuration, monodisperse liposomes and polymersomes are produced in a controlled manner after solvent extraction. Both types of vesicles can be formed from the exact same combination of fluids and are stable for at least three months under ambient storage conditions. By tuning the flow rates of the different fluid phases in the flow-focusing microfluidic design, the size of the liposomes and polymersomes can be varied over at least one order of magnitude. This method offers a versatile tool for future studies, e.g., involving the encapsulation of biological agents and the functionalization of artificial cell membranes, and might also be applicable for the controlled fabrication of hybrid vesicles.

  20. A glycosaminoglycan based, modular tissue scaffold system for rapid assembly of perfusable, high cell density, engineered tissues.

    Directory of Open Access Journals (Sweden)

    Ramkumar Tiruvannamalai-Annamalai

    Full Text Available The limited ability to vascularize and perfuse thick, cell-laden tissue constructs has hindered efforts to engineer complex tissues and organs, including liver, heart and kidney. The emerging field of modular tissue engineering aims to address this limitation by fabricating constructs from the bottom up, with the objective of recreating native tissue architecture and promoting extensive vascularization. In this paper, we report the elements of a simple yet efficient method for fabricating vascularized tissue constructs by fusing biodegradable microcapsules with tunable interior environments. Parenchymal cells of various types, (i.e. trophoblasts, vascular smooth muscle cells, hepatocytes were suspended in glycosaminoglycan (GAG solutions (4%/1.5% chondroitin sulfate/carboxymethyl cellulose, or 1.5 wt% hyaluronan and encapsulated by forming chitosan-GAG polyelectrolyte complex membranes around droplets of the cell suspension. The interior capsule environment could be further tuned by blending collagen with or suspending microcarriers in the GAG solution These capsule modules were seeded externally with vascular endothelial cells (VEC, and subsequently fused into tissue constructs possessing VEC-lined, inter-capsule channels. The microcapsules supported high density growth achieving clinically significant cell densities. Fusion of the endothelialized, capsules generated three dimensional constructs with an embedded network of interconnected channels that enabled long-term perfusion culture of the construct. A prototype, engineered liver tissue, formed by fusion of hepatocyte-containing capsules exhibited urea synthesis rates and albumin synthesis rates comparable to standard collagen sandwich hepatocyte cultures. The capsule based, modular approach described here has the potential to allow rapid assembly of tissue constructs with clinically significant cell densities, uniform cell distribution, and endothelialized, perfusable channels.

  1. Hierarchical self-assembly of actin in micro-confinements using microfluidics

    OpenAIRE

    Deshpande, Siddharth; Pfohl, Thomas

    2012-01-01

    We present a straightforward microfluidics system to achieve step-by-step reaction sequences in a diffusion-controlled manner in quasi two-dimensional micro-confinements. We demonstrate the hierarchical self-organization of actin (actin monomers—entangled networks of filaments—networks of bundles) in a reversible fashion by tuning the Mg2+ ion concentration in the system. We show that actin can form networks of bundles in the presence of Mg2+ without any cross-linking proteins. The properties...

  2. Single-step assembly of homogenous lipid-polymeric and lipid-quantum dot nanoparticles enabled by microfluidic rapid mixing.

    Science.gov (United States)

    Valencia, Pedro M; Basto, Pamela A; Zhang, Liangfang; Rhee, Minsoung; Langer, Robert; Farokhzad, Omid C; Karnik, Rohit

    2010-03-23

    A key challenge in the synthesis of multicomponent nanoparticles (NPs) for therapy or diagnosis is obtaining reproducible monodisperse NPs with a minimum number of preparation steps. Here we report the use of microfluidic rapid mixing using hydrodynamic flow focusing in combination with passive mixing structures to realize the self-assembly of monodisperse lipid-polymer and lipid-quantum dot (QD) NPs in a single mixing step. These NPs are composed of a polymeric core for drug encapsulation or a QD core for imaging purposes, a hydrophilic polymeric shell, and a lipid monolayer at the interface of the core and the shell. In contrast to slow mixing of lipid and polymeric solutions, rapid mixing directly results in formation of homogeneous NPs with relatively narrow size distribution that obviates the need for subsequent thermal or mechanical agitation for homogenization. We identify rapid mixing conditions that result in formation of homogeneous NPs and show that self-assembly of polymeric core occurs independent of the lipid component, which only provides stability against aggregation over time and in the presence of high salt concentrations. Physicochemical properties of the NPs including size (35-180 nm) and zeta potential (-10 to +20 mV in PBS) are controlled by simply varying the composition and concentration of precursors. This method for preparation of hybrid NPs in a single mixing step may be useful for combinatorial synthesis of NPs with different properties for imaging and drug delivery applications. PMID:20166699

  3. Gold Nanoparticle Assembly Microfluidic Reactor for Efficient On-line Proteolysis

    OpenAIRE

    Liu, Y; Xue, Y.; Ji, J; Chen, X; Kong, J.; Yang, P.; Girault, H H

    2007-01-01

    A microchip reactor coated with a gold nanoparticle network entrapping trypsin was designed for the efficient on-line proteolysis of low level proteins and complex extracts originating from mouse macrophages. The nanostructured surface coating was assembled via a layer-bylayer electrostatic binding of poly(diallyldimethylammonium chloride) and gold nanoparticles. The assembly process was monitored by UV-visible spectroscopy, atomic force microscopy, and quartz crystal microbalance. The contro...

  4. Laterally Mobile, Functionalized Self-Assembled Monolayers at the Fluorous-Aqueous Interface in a Plug-Based Microfluidic System: Characterization and Testing with Membrane Protein Crystallization

    OpenAIRE

    Kreutz, Jason E.; Li, Liang; Roach, L. Spencer; Hatakeyama, Takuji; Ismagilov, Rustem F.

    2009-01-01

    This paper describes a method to generate functionalizable, mobile self-assembled monolayers (SAMs) in plug-based microfluidics. Control of interfaces is advancing studies of biological interfaces, heterogeneous reactions, and nanotechnology. SAMs have been useful for such studies, but they are not laterally mobile. Lipid-based methods, though mobile, are not easily amenable to setting up the hundreds of experiments necessary for crystallization screening. Here we demonstrate a method, comple...

  5. Ectopic osteogenesis of macroscopic tissue constructs assembled from human mesenchymal stem cell-laden microcarriers through in vitro perfusion culture.

    Directory of Open Access Journals (Sweden)

    Maiqin Chen

    Full Text Available We had previously demonstrated the feasibility of preparing a centimeter-sized bone tissue construct by following a modular approach. In the present study, the objectives were to evaluate osteogenesis and tissue formation of human amniotic mesenchymal stem cells-laden CultiSpher S microcarriers during in vitro perfusion culture and after subcutaneous implantation. Microtissues were prepared in dynamic culture using spinner flasks in 28 days. In comparison with 1-week perfusion culture, microtissues became more obviously fused, demonstrating significantly higher cellularity, metabolic activity, ALP activity and calcium content while maintaining cell viability after 2-week perfusion. After subcutaneous implantation in nude mice for 6 and 12 weeks, all explants showed tight contexture, suggesting profound tissue remodeling in vivo. In addition, 12-week implantation resulted in slightly better tissue properties. However, in vitro perfusion culture time exerted great influence on the properties of corresponding explants. Degradation of microcarriers was more pronounced in the explants of 2-week perfused macrotissues compared to those of 1-week perfusion and directly implanted microtissues. Moreover, more blood vessel infiltration and bone matrix deposition with homogeneous spatial distribution were found in the explants of 2-week perfused macrotissues. Taken together, in vitro perfusion culture time is critical in engineering bone tissue replacements using such a modular approach, which holds great promise for bone regeneration.

  6. Continuous Microfluidic Self-Assembly of Hybrid Janus-Like Vesicular Motors: Autonomous Propulsion and Controlled Release.

    Science.gov (United States)

    Wang, Lei; Liu, Yijing; He, Jie; Hourwitz, Matthew J; Yang, Yunlong; Fourkas, John T; Han, Xiaojun; Nie, Zhihong

    2015-08-01

    A microfluidic strategy is developed for the continuous fabrication of hybrid Janus vesicular motors that uniquely combine the capability of autonomous propulsion and externally controlled delivery of encapsulated payload. PMID:25925707

  7. Ectopic Osteogenesis of Macroscopic Tissue Constructs Assembled from Human Mesenchymal Stem Cell-Laden Microcarriers through In Vitro Perfusion Culture

    OpenAIRE

    Maiqin Chen; Min Zhou; Zhaoyang Ye; Yan Zhou; Wen-Song Tan

    2014-01-01

    We had previously demonstrated the feasibility of preparing a centimeter-sized bone tissue construct by following a modular approach. In the present study, the objectives were to evaluate osteogenesis and tissue formation of human amniotic mesenchymal stem cells-laden CultiSpher S microcarriers during in vitro perfusion culture and after subcutaneous implantation. Microtissues were prepared in dynamic culture using spinner flasks in 28 days. In comparison with 1-week perfusion culture, microt...

  8. Self-Powered Wireless Affinity-Based Biosensor Based on Integration of Paper-Based Microfluidics and Self-Assembled RFID Antennas.

    Science.gov (United States)

    Yuan, Mingquan; Alocilja, Evangelyn C; Chakrabartty, Shantanu

    2016-08-01

    This paper presents a wireless, self-powered, affinity-based biosensor based on the integration of paper-based microfluidics with our previously reported method for self-assembling radio-frequency (RF) antennas. At the core of the proposed approach is a silver-enhancement technique that grows portions of a RF antenna in regions where target antigens hybridize with target specific affinity probes. The hybridization regions are defined by a network of nitrocellulose based microfluidic channels which implement a self-powered approach to sample the reagent and control its flow and mixing. The integration substrate for the biosensor has been constructed using polyethylene and the patterning of the antenna on the substrate has been achieved using a low-cost ink-jet printing technique. The substrate has been integrated with passive radio-frequency identification (RFID) tags to demonstrate that the resulting sensor-tag can be used for continuous monitoring in a food supply-chain where direct measurement of analytes is typically considered to be impractical. We validate the proof-of-concept operation of the proposed sensor-tag using IgG as a model analyte and using a 915 MHz Ultra-high-frequency (UHF) RFID tagging technology.

  9. Self-Powered Wireless Affinity-Based Biosensor Based on Integration of Paper-Based Microfluidics and Self-Assembled RFID Antennas.

    Science.gov (United States)

    Yuan, Mingquan; Alocilja, Evangelyn C; Chakrabartty, Shantanu

    2016-08-01

    This paper presents a wireless, self-powered, affinity-based biosensor based on the integration of paper-based microfluidics with our previously reported method for self-assembling radio-frequency (RF) antennas. At the core of the proposed approach is a silver-enhancement technique that grows portions of a RF antenna in regions where target antigens hybridize with target specific affinity probes. The hybridization regions are defined by a network of nitrocellulose based microfluidic channels which implement a self-powered approach to sample the reagent and control its flow and mixing. The integration substrate for the biosensor has been constructed using polyethylene and the patterning of the antenna on the substrate has been achieved using a low-cost ink-jet printing technique. The substrate has been integrated with passive radio-frequency identification (RFID) tags to demonstrate that the resulting sensor-tag can be used for continuous monitoring in a food supply-chain where direct measurement of analytes is typically considered to be impractical. We validate the proof-of-concept operation of the proposed sensor-tag using IgG as a model analyte and using a 915 MHz Ultra-high-frequency (UHF) RFID tagging technology. PMID:27214914

  10. Cu2+ Detection with Gold Nanoparticles by Patterning Colorimetric Strips on a Filter Membrane Assembled in a Microfluidic Chip%Cu2+ Detection with Gold Nanoparticles by Patterning Colorimetric Strips on a Filter Membrane Assembled in a Microfluidic Chip

    Institute of Scientific and Technical Information of China (English)

    刘颖昳; 虞洁; 陈雯雯; 刘定斌; 王卓; 蒋兴宇

    2012-01-01

    We have developed a microfluidic chip for colorimetric CH2+ detection. In this chip, it is facile to do colorimet- ric Cu2+ detection based on gold nanoparticles. This method has a dynamic detection range from 0.75 to 50 lamol/L with only 20μL solution including detection reagents and sample. The result can be readout by naked eye and pho-tographed by digital cameras. With the help of image processing software, we could measure the RGB value and calculate the Blue/Red ratio for more accurate quantification. Tap water could be detected in this portable chip.

  11. Assembly of cell-laden hydrogel fiber into non-liquefied and liquefied 3D spiral constructs by perfusion-based layer-by-layer technique.

    Science.gov (United States)

    Sher, Praveen; Oliveira, Sara M; Borges, João; Mano, João F

    2015-01-01

    In this work, three-dimensional (3D) self-sustaining, spiral-shaped constructs were produced through a combination of ionotropic gelation, to form cell-encapsulated alginate fibers, and a perfusion-based layer-by-layer (LbL) technique. Single fibers were assembled over cylindrical molds by reeling to form spiral shapes, both having different geometries and sizes. An uninterrupted nanometric multilayer coating produced by a perfusion-based LbL technique, using alginate and chitosan, generated stable 3D spiral-shaped macrostructures by gripping and affixing the threads together without using any crosslinking/binding agent. The chelation process altered the internal microenvironment of the 3D construct from the solid to the liquefied state while preserving the external geometry. L929 cell viability by MTS and dsDNA quantification favor liquefied 3D constructs more than non-liquefied ones. The proposed technique setup helps us to generate complex polyelectrolyte-based 3D constructs for tissue engineering applications and organ printing. PMID:25562702

  12. Microfluidic electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2012-08-21

    Microfluidics, a field that has been well-established for several decades, has seen extensive applications in the areas of biology, chemistry, and medicine. However, it might be very hard to imagine how such soft microfluidic devices would be used in other areas, such as electronics, in which stiff, solid metals, insulators, and semiconductors have previously dominated. Very recently, things have radically changed. Taking advantage of native properties of microfluidics, advances in microfluidics-based electronics have shown great potential in numerous new appealing applications, e.g. bio-inspired devices, body-worn healthcare and medical sensing systems, and ergonomic units, in which conventional rigid, bulky electronics are facing insurmountable obstacles to fulfil the demand on comfortable user experience. Not only would the birth of microfluidic electronics contribute to both the microfluidics and electronics fields, but it may also shape the future of our daily life. Nevertheless, microfluidic electronics are still at a very early stage, and significant efforts in research and development are needed to advance this emerging field. The intention of this article is to review recent research outcomes in the field of microfluidic electronics, and address current technical challenges and issues. The outlook of future development in microfluidic electronic devices and systems, as well as new fabrication techniques, is also discussed. Moreover, the authors would like to inspire both the microfluidics and electronics communities to further exploit this newly-established field.

  13. Laterally Mobile, Functionalized Self-Assembled Monolayers at the Fluorous−Aqueous Interface in a Plug-Based Microfluidic System: Characterization and Testing with Membrane Protein Crystallization

    Energy Technology Data Exchange (ETDEWEB)

    Kreutz, Jason E.; Li, Liang; Roach, L. Spencer; Hatakeyama, Takuji; Ismagilov, Rustem F.; (UC)

    2009-11-04

    This paper describes a method to generate functionalizable, mobile self-assembled monolayers (SAMs) in plug-based microfluidics. Control of interfaces is advancing studies of biological interfaces, heterogeneous reactions, and nanotechnology. SAMs have been useful for such studies, but they are not laterally mobile. Lipid-based methods, though mobile, are not easily amenable to setting up the hundreds of experiments necessary for crystallization screening. Here we demonstrate a method, complementary to current SAM and lipid methods, for rapidly generating mobile, functionalized SAMs. This method relies on plugs, droplets surrounded by a fluorous carrier fluid, to rapidly explore chemical space. Specifically, we implemented his-tag binding chemistry to design a new fluorinated amphiphile, RfNTA, using an improved one-step synthesis of RfOEG under Mitsunobu conditions. RfNTA introduces specific binding of protein at the fluorous-aqueous interface, which concentrates and orients proteins at the interface, even in the presence of other surfactants. We then applied this approach to the crystallization of a his-tagged membrane protein, Reaction Center from Rhodobacter sphaeroides, performed 2400 crystallization trials, and showed that this approach can increase the range of crystal-producing conditions, the success rate at a given condition, the rate of nucleation, and the quality of the crystal formed.

  14. Tailoring microfluidic systems for organ-like cell culture applications using multiphysics simulations

    Science.gov (United States)

    Hagmeyer, Britta; Schütte, Julia; Böttger, Jan; Gebhardt, Rolf; Stelzle, Martin

    2013-03-01

    Replacing animal testing with in vitro cocultures of human cells is a long-term goal in pre-clinical drug tests used to gain reliable insight into drug-induced cell toxicity. However, current state-of-the-art 2D or 3D cell cultures aiming at mimicking human organs in vitro still lack organ-like morphology and perfusion and thus organ-like functions. To this end, microfluidic systems enable construction of cell culture devices which can be designed to more closely resemble the smallest functional unit of organs. Multiphysics simulations represent a powerful tool to study the various relevant physical phenomena and their impact on functionality inside microfluidic structures. This is particularly useful as it allows for assessment of system functions already during the design stage prior to actual chip fabrication. In the HepaChip®, dielectrophoretic forces are used to assemble human hepatocytes and human endothelial cells in liver sinusoid-like structures. Numerical simulations of flow distribution, shear stress, electrical fields and heat dissipation inside the cell assembly chambers as well as surface wetting and surface tension effects during filling of the microchannel network supported the design of this human-liver-on-chip microfluidic system for cell culture applications. Based on the device design resulting thereof, a prototype chip was injection-moulded in COP (cyclic olefin polymer). Functional hepatocyte and endothelial cell cocultures were established inside the HepaChip® showing excellent metabolic and secretory performance.

  15. : microfluidic micropipette

    OpenAIRE

    Preira, Pascal; Valignat, Marie-Pierre; Bico, José; Théodoly, Olivier

    2013-01-01

    International audience We report how cell rheology measurements can be performed by monitoring the deformation of a cell in a microfluidic constriction, provided that friction and fluid leaks effects between the cell and the walls of the microchannels are correctly taken into account. Indeed, the mismatch between the rounded shapes of cells and the angular cross-section of standard microfluidic channels hampers efficient obstruction of the channel by an incoming cell. Moreover, friction fo...

  16. Renal perfusion scintiscan

    Science.gov (United States)

    Renal perfusion scintigraphy; Radionuclide renal perfusion scan; Perfusion scintiscan - renal; Scintiscan - renal perfusion ... supply the kidneys. This is a condition called renal artery stenosis. Significant renal artery stenosis may be ...

  17. A Reversibly Sealed, Easy Access, Modular (SEAM Microfluidic Architecture to Establish In Vitro Tissue Interfaces.

    Directory of Open Access Journals (Sweden)

    Vinay V Abhyankar

    Full Text Available Microfluidic barrier tissue models have emerged as advanced in vitro tools to explore interactions with external stimuli such as drug candidates, pathogens, or toxins. However, the procedures required to establish and maintain these systems can be challenging to implement for end users, particularly those without significant in-house engineering expertise. Here we present a module-based approach that provides an easy-to-use workflow to establish, maintain, and analyze microscale tissue constructs. Our approach begins with a removable culture insert that is magnetically coupled, decoupled, and transferred between standalone, prefabricated microfluidic modules for simplified cell seeding, culture, and downstream analysis. The modular approach allows several options for perfusion including standard syringe pumps or integration with a self-contained gravity-fed module for simple cell maintenance. As proof of concept, we establish a culture of primary human microvascular endothelial cells (HMVEC and report combined surface protein imaging and gene expression after controlled apical stimulation with the bacterial endotoxin lipopolysaccharide (LPS. We also demonstrate the feasibility of incorporating hydrated biomaterial interfaces into the microfluidic architecture by integrating an ultra-thin (< 1 μm, self-assembled hyaluronic acid/peptide amphiphile culture membrane with brain-specific Young's modulus (~ 1kPa. To highlight the importance of including biomimetic interfaces into microscale models we report multi-tiered readouts from primary rat cortical cells cultured on the self-assembled membrane and compare a panel of mRNA targets with primary brain tissue signatures. We anticipate that the modular approach and simplified operational workflows presented here will enable a wide range of research groups to incorporate microfluidic barrier tissue models into their work.

  18. A hybrid microsystem for parallel perfusion experiments on living cells

    Science.gov (United States)

    Greve, Frauke; Seemann, Livia; Hierlemann, Andreas; Lichtenberg, Jan

    2007-08-01

    A fully integrated microchip device for performing a complete and automated sample-perfusion experiment on living cells is presented. Cells were trapped and immobilized in a defined grid pattern inside a small 0.5 µl volume incubation chamber by pneumatic anchoring on 1000 5-µm orifices. This new cell trapping technique assures a precise and repeatable cell quantity for each experiment and enables the formation of a homogeneous cell population in the incubation chamber. The microsystem includes a perforated silicon chip seamlessly integrated by a new embedding technique in a larger elastomer substrate, which features the microfluidic network. The latter forms the incubation chamber and allows for economic logarithmic dilution of the sample reagent over a range of three orders of magnitude with subsequent perfusion of the cell population. First, the logarithmic dilution stage was validated using quantitative fluorescent imaging of fluorescein solution. Then, the cell adhesion and culturing inside the incubation chamber was studied using primary normal human dermal fibroblasts (NHDFs). The cells adhered well on laminin-coated surfaces and proliferated to form a confluent cell layer after 6 days in vitro. Finally, the complete system was tested by a perfusion experiment with cultured NHDFs, which were exposed to a fluorescent cell tracker at dilutions of 100 µm, 10 µm, 1 µm, 0.1 µm and 0 µm at a flow rate of 1.25 µl min-1 for 20 min. Fluorescence imaging of the cell array after incubation and image analysis showed a logarithmic relationship between sample concentration and the fluorescence signal. This paper describes the fabrication of the components and the assembly of the microsystem, the design approach and the validation of the sample diluter, cell-adhesion and cell-culturing experiments over several days.

  19. Theoretical microfluidics

    DEFF Research Database (Denmark)

    Bruus, Henrik

    introducing microfluidics, the governing equations for mass, momentum and energy, and some basic flow solutions, the following 14 chapters treat hydraulic resistance/compliance, diffusion/dispersion, time-dependent flow, capillarity, electro- and magneto-hydrodynamics, thermal transport, two-phase flow...

  20. Microfluidic Device

    Science.gov (United States)

    Tai, Yu-Chong (Inventor); Zheng, Siyang (Inventor); Lin, Jeffrey Chun-Hui (Inventor); Kasdan, Harvey L. (Inventor)

    2016-01-01

    Described herein are particular embodiments relating to a microfluidic device that may be utilized for cell sensing, counting, and/or sorting. Particular aspects relate to a microfabricated device that is capable of differentiating single cell types from dense cell populations. One particular embodiment relates a device and methods of using the same for sensing, counting, and/or sorting leukocytes from whole, undiluted blood samples.

  1. Microfluidic waves.

    Science.gov (United States)

    Utz, Marcel; Begley, Matthew R; Haj-Hariri, Hossein

    2011-11-21

    The propagation of pressure waves in fluidic channels with elastic covers is discussed in view of applications to flow control in microfluidic devices. A theory is presented which describes pressure waves in the fluid that are coupled to bending waves in the elastic cover. At low frequencies, the lateral bending of the cover dominates over longitudinal bending, leading to propagating, non-dispersive longitudinal pressure waves in the channel. The theory addresses effects due to both the finite viscosity and compressibility of the fluid. The coupled waves propagate without dispersion, as long as the wave length is larger than the channel width. It is shown that in channels of typical microfluidic dimensions, wave velocities in the range of a few 10 m s(-1) result if the channels are covered by films of a compliant material such as PDMS. The application of this principle to design microfluidic band pass filters based on standing waves is discussed. Characteristic frequencies in the range of a few kHz are readily achieved with quality factors above 30. PMID:21966667

  2. Scalable Approach for Extrusion and Perfusion of Tubular, Heterotypic Biomaterials

    Science.gov (United States)

    Jeronimo, Mark David

    Soft material tubes are critical in the vasculature of mammalian tissues, forming networks of blood vessels and airways. Homogeneous and heterogeneous hydrogel tubes were extruded in a one-step process using a three layer microfluidic device. Co-axial cylindrical flow of crosslinking solutions and an alginate matrix is generated by a radial arrangement of microfluidic channels at the device's vertical extrusion outlet. The flow is confined and begins a sol-gel transition immediately as it extrudes at velocities upwards of 4 mm/s. This approach allows for predictive control over the dimensions of the rapidly formed tubular structures for outer diameters from 600 microm to 3 mm. A second microfluidic device hosts tube segments for controlled perfusion and pressurization using a reversible vacuum seal. On-chip tube deflection is observed and modeled as a measure of material compliance and circumferential elasticity. I anticipate applications of these devices for perfusion cell culture of cell-laden hydrogel tubes.

  3. Multidimensional bioseparation with modular microfluidics

    Science.gov (United States)

    Chirica, Gabriela S.; Renzi, Ronald F.

    2013-08-27

    A multidimensional chemical separation and analysis system is described including a prototyping platform and modular microfluidic components capable of rapid and convenient assembly, alteration and disassembly of numerous candidate separation systems. Partial or total computer control of the separation system is possible. Single or multiple alternative processing trains can be tested, optimized and/or run in parallel. Examples related to the separation and analysis of human bodily fluids are given.

  4. Microfluidic bioreactors for culture of non-adherent cells

    DEFF Research Database (Denmark)

    Shah, Pranjul Jaykumar; Vedarethinam, Indumathi; Kwasny, Dorota;

    2011-01-01

    Microfluidic bioreactors (μBR) are becoming increasingly popular for cell culture, sample preparation and analysis in case of routine genetic and clinical diagnostics. We present a novel μBR for non-adherent cells designed to mimic in vivo perfusion of cells based on diffusion of media through...

  5. Synthesis and cell-free cloning of DNA libraries using programmable microfluidics

    OpenAIRE

    Yehezkel, Tuval Ben; Rival, Arnaud; Raz, Ofir; Cohen, Rafael; Marx, Zipora; Camara, Miguel; Dubern, Jean-Frédéric; Koch, Birgit; Heeb, Stephan; Krasnogor, Natalio; Delattre, Cyril; Shapiro, Ehud

    2015-01-01

    Microfluidics may revolutionize our ability to write synthetic DNA by addressing several fundamental limitations associated with generating novel genetic constructs. Here we report the first de novo synthesis and cell-free cloning of custom DNA libraries in sub-microliter reaction droplets using programmable digital microfluidics. Specifically, we developed Programmable Order Polymerization (POP), Microfluidic Combinatorial Assembly of DNA (M-CAD) and Microfluidic In-vitro Cloning (MIC) and a...

  6. Electro-Microfluidic Packaging

    Science.gov (United States)

    Benavides, G. L.; Galambos, P. C.

    2002-06-01

    There are many examples of electro-microfluidic products that require cost effective packaging solutions. Industry has responded to a demand for products such as drop ejectors, chemical sensors, and biological sensors. Drop ejectors have consumer applications such as ink jet printing and scientific applications such as patterning self-assembled monolayers or ejecting picoliters of expensive analytes/reagents for chemical analysis. Drop ejectors can be used to perform chemical analysis, combinatorial chemistry, drug manufacture, drug discovery, drug delivery, and DNA sequencing. Chemical and biological micro-sensors can sniff the ambient environment for traces of dangerous materials such as explosives, toxins, or pathogens. Other biological sensors can be used to improve world health by providing timely diagnostics and applying corrective measures to the human body. Electro-microfluidic packaging can easily represent over fifty percent of the product cost and, as with Integrated Circuits (IC), the industry should evolve to standard packaging solutions. Standard packaging schemes will minimize cost and bring products to market sooner.

  7. Microfluidic electrochemical reactors

    Science.gov (United States)

    Nuzzo, Ralph G.; Mitrovski, Svetlana M.

    2011-03-22

    A microfluidic electrochemical reactor includes an electrode and one or more microfluidic channels on the electrode, where the microfluidic channels are covered with a membrane containing a gas permeable polymer. The distance between the electrode and the membrane is less than 500 micrometers. The microfluidic electrochemical reactor can provide for increased reaction rates in electrochemical reactions using a gaseous reactant, as compared to conventional electrochemical cells. Microfluidic electrochemical reactors can be incorporated into devices for applications such as fuel cells, electrochemical analysis, microfluidic actuation, pH gradient formation.

  8. A Review of Biomedical Centrifugal Microfluidic Platforms

    Directory of Open Access Journals (Sweden)

    Minghui Tang

    2016-02-01

    Full Text Available Centrifugal microfluidic or lab-on-a-disc platforms have many advantages over other microfluidic systems. These advantages include a minimal amount of instrumentation, the efficient removal of any disturbing bubbles or residual volumes, and inherently available density-based sample transportation and separation. Centrifugal microfluidic devices applied to biomedical analysis and point-of-care diagnostics have been extensively promoted recently. This paper presents an up-to-date overview of these devices. The development of biomedical centrifugal microfluidic platforms essentially covers two categories: (i unit operations that perform specific functionalities, and (ii systems that aim to address certain biomedical applications. With the aim to provide a comprehensive representation of current development in this field, this review summarizes progress in both categories. The advanced unit operations implemented for biological processing include mixing, valving, switching, metering and sequential loading. Depending on the type of sample to be used in the system, biomedical applications are classified into four groups: nucleic acid analysis, blood analysis, immunoassays, and other biomedical applications. Our overview of advanced unit operations also includes the basic concepts and mechanisms involved in centrifugal microfluidics, while on the other hand an outline on reported applications clarifies how an assembly of unit operations enables efficient implementation of various types of complex assays. Lastly, challenges and potential for future development of biomedical centrifugal microfluidic devices are discussed.

  9. Microfluidic sieve valves

    Science.gov (United States)

    Quake, Stephen R; Marcus, Joshua S; Hansen, Carl L

    2015-01-13

    Sieve valves for use in microfluidic device are provided. The valves are useful for impeding the flow of particles, such as chromatography beads or cells, in a microfluidic channel while allowing liquid solution to pass through the valve. The valves find particular use in making microfluidic chromatography modules.

  10. Microfluidic Dye Lasers

    DEFF Research Database (Denmark)

    Kristensen, Anders; Balslev, Søren; Gersborg-Hansen, Morten;

    2006-01-01

    A technology for miniaturized, polymer based lasers, suitable for integration with planar waveguides and microfluidic networks is presented. The microfluidic dye laser device consists of a microfluidic channel with an embedded optical resonator. The devices are fabricated in a thin polymer film...

  11. Hyaluronic Acid-Based Nanogels Produced by Microfluidics-Facilitated Self-Assembly Improves the Safety Profile of the Cationic Host Defense Peptide Novicidin

    DEFF Research Database (Denmark)

    Water, Jorrit J; Kim, YongTae; Maltesen, Morten J;

    2015-01-01

    peptide loading of 36 ± 4%. The nanogels exhibited good colloidal stability under different ionic strength conditions and allowed complete release of the peptide over 14 days. Furthermore, self-assembly of novicidin with hyaluronic acid into nanogels significantly improved the safety profile at least five...

  12. Pulmonary ventilation/perfusion scan

    Science.gov (United States)

    V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan ... A pulmonary ventilation/perfusion scan is actually two tests. They may be done separately or together. During the perfusion scan, a health care ...

  13. Pulmonary ventilation/perfusion scan

    Science.gov (United States)

    V/Q scan; Ventilation/perfusion scan; Lung ventilation/perfusion scan ... A pulmonary ventilation/perfusion scan is actually two tests. They may be done separately or together. During the perfusion scan, a health ...

  14. Digital Microfluidics Sample Analyzer

    Science.gov (United States)

    Pollack, Michael G.; Srinivasan, Vijay; Eckhardt, Allen; Paik, Philip Y.; Sudarsan, Arjun; Shenderov, Alex; Hua, Zhishan; Pamula, Vamsee K.

    2010-01-01

    Three innovations address the needs of the medical world with regard to microfluidic manipulation and testing of physiological samples in ways that can benefit point-of-care needs for patients such as premature infants, for which drawing of blood for continuous tests can be life-threatening in their own right, and for expedited results. A chip with sample injection elements, reservoirs (and waste), droplet formation structures, fluidic pathways, mixing areas, and optical detection sites, was fabricated to test the various components of the microfluidic platform, both individually and in integrated fashion. The droplet control system permits a user to control droplet microactuator system functions, such as droplet operations and detector operations. Also, the programming system allows a user to develop software routines for controlling droplet microactuator system functions, such as droplet operations and detector operations. A chip is incorporated into the system with a controller, a detector, input and output devices, and software. A novel filler fluid formulation is used for the transport of droplets with high protein concentrations. Novel assemblies for detection of photons from an on-chip droplet are present, as well as novel systems for conducting various assays, such as immunoassays and PCR (polymerase chain reaction). The lab-on-a-chip (a.k.a., lab-on-a-printed-circuit board) processes physiological samples and comprises a system for automated, multi-analyte measurements using sub-microliter samples of human serum. The invention also relates to a diagnostic chip and system including the chip that performs many of the routine operations of a central labbased chemistry analyzer, integrating, for example, colorimetric assays (e.g., for proteins), chemiluminescence/fluorescence assays (e.g., for enzymes, electrolytes, and gases), and/or conductometric assays (e.g., for hematocrit on plasma and whole blood) on a single chip platform.

  15. Ventilation-perfusion scintigraphy

    International Nuclear Information System (INIS)

    A historical review of different investigation methods measuring lung function (perfusion and gas exchange) is given. The principles and handling of some ventilation methods using radioxenon, radiokrypton or radiolabelled aerosols, and the injection method of xenon are explained. The clinical applicability of these studies is evaluated considering ventilation and perfusion lung defects and congestive heart failure. The combination of the three principal techniques (perfusion scintigraphy using MAA, ventilation scintigraphy using radioxenon or radiokrypton, perfusion and ventilation scientigraphy after injection of radioxenon) lead to typical patterns of differential diagnosis of perfusion defects. (TRV)

  16. Mechanically activated artificial cell by using microfluidics.

    Science.gov (United States)

    Ho, Kenneth K Y; Lee, Lap Man; Liu, Allen P

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology.

  17. Mechanically activated artificial cell by using microfluidics

    Science.gov (United States)

    Ho, Kenneth K. Y.; Lee, Lap Man; Liu, Allen P.

    2016-01-01

    All living organisms sense mechanical forces. Engineering mechanosensitive artificial cell through bottom-up in vitro reconstitution offers a way to understand how mixtures of macromolecules assemble and organize into a complex system that responds to forces. We use stable double emulsion droplets (aqueous/oil/aqueous) to prototype mechanosensitive artificial cells. In order to demonstrate mechanosensation in artificial cells, we develop a novel microfluidic device that is capable of trapping double emulsions into designated chambers, followed by compression and aspiration in a parallel manner. The microfluidic device is fabricated using multilayer soft lithography technology, and consists of a control layer and a deformable flow channel. Deflections of the PDMS membrane above the main microfluidic flow channels and trapping chamber array are independently regulated pneumatically by two sets of integrated microfluidic valves. We successfully compress and aspirate the double emulsions, which result in transient increase and permanent decrease in oil thickness, respectively. Finally, we demonstrate the influx of calcium ions as a response of our mechanically activated artificial cell through thinning of oil. The development of a microfluidic device to mechanically activate artificial cells creates new opportunities in force-activated synthetic biology. PMID:27610921

  18. Miniaturization and microfluidics

    OpenAIRE

    Foret, F; Smejkal, P.; Macka, M.

    2013-01-01

    While miniaturization is a prerequisite of achieving portability in LC systems, microfluidics represents a qualitative step toward chip-based LC systems. This short chapter provides an excursion into the microfluidics for separations with a brief overview of some of the commercial systems. It is worth stressing that, while the development and introduction of new microfluidic instrumentation is just at its beginning, the miniaturized technology is being used quite often in commercial sys...

  19. Microfluidics in biotechnology

    OpenAIRE

    Ivanov Dimitri; Barry Richard

    2004-01-01

    Abstract Microfluidics enables biotechnological processes to proceed on a scale (microns) at which physical processes such as osmotic movement, electrophoretic-motility and surface interactions become enhanced. At the microscale sample volumes and assay times are reduced, and procedural costs are lowered. The versatility of microfluidic devices allows interfacing with current methods and technologies. Microfluidics has been applied to DNA analysis methods and shown to accelerate DNA microarra...

  20. Tunable Microfluidic Dye Laser

    DEFF Research Database (Denmark)

    Olsen, Brian Bilenberg; Helbo, Bjarne; Kutter, Jörg Peter;

    2003-01-01

    We present a tunable microfluidic dye laser fabricated in SU-8. The tunability is enabled by integrating a microfluidic diffusion mixer with an existing microfluidic dye laser design by Helbo et al. By controlling the relative flows in the mixer between a dye solution and a solvent......, the concentration of dye in the laser cavity can be adjusted, allowing the wavelength to be tuned. Wavelength tuning controlled by the dye concentration was demonstrated with macroscopic dye lasers already in 1971, but this principle only becomes practically applicable by the use of microfluidic mixing...

  1. Microfluidic stretchable RF electronics.

    Science.gov (United States)

    Cheng, Shi; Wu, Zhigang

    2010-12-01

    Stretchable electronics is a revolutionary technology that will potentially create a world of radically different electronic devices and systems that open up an entirely new spectrum of possibilities. This article proposes a microfluidic based solution for stretchable radio frequency (RF) electronics, using hybrid integration of active circuits assembled on flex foils and liquid alloy passive structures embedded in elastic substrates, e.g. polydimethylsiloxane (PDMS). This concept was employed to implement a 900 MHz stretchable RF radiation sensor, consisting of a large area elastic antenna and a cluster of conventional rigid components for RF power detection. The integrated radiation sensor except the power supply was fully embedded in a thin elastomeric substrate. Good electrical performance of the standalone stretchable antenna as well as the RF power detection sub-module was verified by experiments. The sensor successfully detected the RF radiation over 5 m distance in the system demonstration. Experiments on two-dimensional (2D) stretching up to 15%, folding and twisting of the demonstrated sensor were also carried out. Despite the integrated device was severely deformed, no failure in RF radiation sensing was observed in the tests. This technique illuminates a promising route of realizing stretchable and foldable large area integrated RF electronics that are of great interest to a variety of applications like wearable computing, health monitoring, medical diagnostics, and curvilinear electronics.

  2. Laser doppler perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Waardell, K.

    1992-01-01

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 {mu}m. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs.

  3. Laser doppler perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Waardell, K.

    1992-11-01

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 {mu}m. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs.

  4. Laser doppler perfusion imaging

    International Nuclear Information System (INIS)

    Recording of tissue perfusion is important in assessing the influence of peripheral vascular diseases on the microcirculation. This thesis reports on a laser doppler perfusion imager based on dynamic light scattering in tissue. When a low power He-Ne laser beam sequentally scans the tissue, moving blood cells generate doppler components in the back-scattered light. A fraction of this light is detected by a photodetector and converted into an electrical signal. In the processor, a signal proportional to the tissue perfusion at each measurement site is calculated and stored. When the scanning procedure is completed, a color-coded perfusion image is presented on a monitor. To convert important aspects of the perfusion image into more quantitative parameters, data analysis functions are implemented in the software. A theory describing the dependence of the distance between individual measurement points and detector on the system amplification factor is proposed and correction algorithms are presented. The performance of the laser doppler perfusion imager was evaluated using a flow simulator. A linear relationship between processor output signal and flow through the simulator was demonstrated for blood cell concentrations below 0.2%. The median sampling depth of the laser beam was simulated by a Monte Carlo technique and estimated to 235 μm. The perfusion imager has been used in the clinic to study perfusion changes in port wine stains treated with argon laser and to investigate the intensity and extension of the cutaneous axon reflex response after electrical nerve stimulation. The fact that perfusion can be visualized without touching the tissue implies elimination of sterilization problems, thus simplifying clinical investigations of perfusion in association with diagnosis and treatment of peripheral vascular diseases. 22 refs

  5. Optimized fabrication protocols of microfluidic devices for X-ray analysis

    KAUST Repository

    Catalano, Rossella

    2014-07-01

    Microfluidics combined with X-ray scattering techniques allows probing conformational changes or assembly processes of biological materials. Our aim was to develop a highly X-ray transparent microfluidic cell for detecting small variations of X-ray scattering involved in such processes. We describe the fabrication of a polyimide microfluidic device based on a simple, reliable and inexpensive lamination process. The implemented microstructured features result in windows with optimized X-ray transmission. The microfluidic device was characterized by X-ray microbeam scattering at the ID13 beamline of the European Synchrotron Radiation Facility. © 2014 Elsevier B.V. All rights reserved.

  6. Microfluidics and microbial engineering.

    Science.gov (United States)

    Kou, Songzi; Cheng, Danhui; Sun, Fei; Hsing, I-Ming

    2016-02-01

    The combination of microbial engineering and microfluidics is synergistic in nature. For example, microfluidics is benefiting from the outcome of microbial engineering and many reported point-of-care microfluidic devices employ engineered microbes as functional parts for the microsystems. In addition, microbial engineering is facilitated by various microfluidic techniques, due to their inherent strength in high-throughput screening and miniaturization. In this review article, we firstly examine the applications of engineered microbes for toxicity detection, biosensing, and motion generation in microfluidic platforms. Secondly, we look into how microfluidic technologies facilitate the upstream and downstream processes of microbial engineering, including DNA recombination, transformation, target microbe selection, mutant characterization, and microbial function analysis. Thirdly, we highlight an emerging concept in microbial engineering, namely, microbial consortium engineering, where the behavior of a multicultural microbial community rather than that of a single cell/species is delineated. Integrating the disciplines of microfluidics and microbial engineering opens up many new opportunities, for example in diagnostics, engineering of microbial motors, development of portable devices for genetics, high throughput characterization of genetic mutants, isolation and identification of rare/unculturable microbial species, single-cell analysis with high spatio-temporal resolution, and exploration of natural microbial communities.

  7. Nanomaterials meet microfluidics.

    Science.gov (United States)

    Pumera, Martin

    2011-05-28

    Nanomaterials and lab-on-a-chip platforms have undergone enormous development during the past decade. Here, we present an overview of how microfluidics benefited from the use of nanomaterials for the enhanced separation and detection of analytes. We also discuss how nanomaterials benefit from microfluidics in terms of synthesis and in terms of the simulation of environments for nanomotors and nanorobots. In our opinion, the "marriage" of nanomaterials and microfluidics is highly beneficial and is expected to solve vital challenges in related fields.

  8. Synthesis and cell-free cloning of DNA libraries using programmable microfluidics.

    Science.gov (United States)

    Ben Yehezkel, Tuval; Rival, Arnaud; Raz, Ofir; Cohen, Rafael; Marx, Zipora; Camara, Miguel; Dubern, Jean-Frédéric; Koch, Birgit; Heeb, Stephan; Krasnogor, Natalio; Delattre, Cyril; Shapiro, Ehud

    2016-02-29

    Microfluidics may revolutionize our ability to write synthetic DNA by addressing several fundamental limitations associated with generating novel genetic constructs. Here we report the first de novo synthesis and cell-free cloning of custom DNA libraries in sub-microliter reaction droplets using programmable digital microfluidics. Specifically, we developed Programmable Order Polymerization (POP), Microfluidic Combinatorial Assembly of DNA (M-CAD) and Microfluidic In-vitro Cloning (MIC) and applied them to de novo synthesis, combinatorial assembly and cell-free cloning of genes, respectively. Proof-of-concept for these methods was demonstrated by programming an autonomous microfluidic system to construct and clone libraries of yeast ribosome binding sites and bacterial Azurine, which were then retrieved in individual droplets and validated. The ability to rapidly and robustly generate designer DNA molecules in an autonomous manner should have wide application in biological research and development. PMID:26481354

  9. Synthesis and cell-free cloning of DNA libraries using programmable microfluidics

    Science.gov (United States)

    Yehezkel, Tuval Ben; Rival, Arnaud; Raz, Ofir; Cohen, Rafael; Marx, Zipora; Camara, Miguel; Dubern, Jean-Frédéric; Koch, Birgit; Heeb, Stephan; Krasnogor, Natalio; Delattre, Cyril; Shapiro, Ehud

    2016-01-01

    Microfluidics may revolutionize our ability to write synthetic DNA by addressing several fundamental limitations associated with generating novel genetic constructs. Here we report the first de novo synthesis and cell-free cloning of custom DNA libraries in sub-microliter reaction droplets using programmable digital microfluidics. Specifically, we developed Programmable Order Polymerization (POP), Microfluidic Combinatorial Assembly of DNA (M-CAD) and Microfluidic In-vitro Cloning (MIC) and applied them to de novo synthesis, combinatorial assembly and cell-free cloning of genes, respectively. Proof-of-concept for these methods was demonstrated by programming an autonomous microfluidic system to construct and clone libraries of yeast ribosome binding sites and bacterial Azurine, which were then retrieved in individual droplets and validated. The ability to rapidly and robustly generate designer DNA molecules in an autonomous manner should have wide application in biological research and development. PMID:26481354

  10. Microfluidic chemical reaction circuits

    Science.gov (United States)

    Lee, Chung-cheng; Sui, Guodong; Elizarov, Arkadij; Kolb, Hartmuth C.; Huang, Jiang; Heath, James R.; Phelps, Michael E.; Quake, Stephen R.; Tseng, Hsian-rong; Wyatt, Paul; Daridon, Antoine

    2012-06-26

    New microfluidic devices, useful for carrying out chemical reactions, are provided. The devices are adapted for on-chip solvent exchange, chemical processes requiring multiple chemical reactions, and rapid concentration of reagents.

  11. Punch Card Programmable Microfluidics

    CERN Document Server

    Korir, George

    2014-01-01

    Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external components has remained elusive. Combining the idea of punch card programming with arbitrary fluid control, here we describe a self-contained, hand-crank powered, multiplex and robust programmable microfluidic platform. A paper tape encodes information as a series of punched holes. A mechanical reader/actuator reads these paper tapes and correspondingly executes a series of operations onto a microfluidic chip coupled to the platform in a plug-and-play fashion. Enabled by the complexity of codes that can be represented by a series ...

  12. Perfusion Linearity and Its Applications

    CERN Document Server

    Pianykh, Oleg

    2010-01-01

    Perfusion analysis computes blood flow parameters (blood volume, blood flow, mean transit time) from the observed flow of contrast agent, passing through the patient's vascular system. Perfusion deconvolution has been widely accepted as the principal numerical tool for perfusion analysis, and is used routinely in clinical applications. This extensive use of perfusion in clinical decision-making makes numerical stability and robustness of perfusion computations vital for accurate diagnostics and patient safety. The main goal of this paper is to propose a novel approach for validating numerical properties of perfusion algorithms. The approach is based on Perfusion Linearity Property (PLP), which we find in perfusion deconvolution, as well as in many other perfusion techniques. PLP allows one to study perfusion values as weighted averages of the original imaging data. This, in turn, uncovers hidden problems with the existing deconvolution techniques, and may be used to suggest more reliable computational approac...

  13. Microfluidic CARS cytometry

    OpenAIRE

    Wang, Han-Wei; Bao, Ning; Le, Thuc T.; Lu, Chang; Cheng, Ji-Xin

    2008-01-01

    Coherent anti-stokes Raman scattering (CARS) flow cytometry was demonstrated by combining a laser-scanning CARS microscope with a polydimethylsiloxane (PDMS) based microfluidic device. Line-scanning across the hydrodynamically focused core stream was performed for detection of flowing objects. Parameters were optimized by utilizing polystyrene beads as flowing particles. Population measurements of adipocytes isolated from mouse fat tissues demonstrated the viability of microfluidic CARS cytom...

  14. Microfluidic isotachophoresis: A review

    OpenAIRE

    Smejkal, P.; Bottenus, D.; Breadmore, M.C.; Van Guijt, R.M.; Ivory, C. F.; Foret, F; Macka, M.

    2013-01-01

    Electromigration methods including CE and ITP are attractive for incorporation in microfluidic devices because they are relatively easily adaptable to miniaturization. After its popularity in the 1970s, ITP has made a comeback in microfluidic format (-ITP, micro-ITP) driven by the advantages of the steady-state boundary, the self-focusing effect, and the ability to aid in preconcentrating analytes in the sample while removing matrix components. In this review, we provide an overview of the de...

  15. Punch Card Programmable Microfluidics

    OpenAIRE

    George Korir; Manu Prakash

    2014-01-01

    Small volume fluid handling in single and multiphase microfluidics provides a promising strategy for efficient bio-chemical assays, low-cost point-of-care diagnostics and new approaches to scientific discoveries. However multiple barriers exist towards low-cost field deployment of programmable microfluidics. Incorporating multiple pumps, mixers and discrete valve based control of nanoliter fluids and droplets in an integrated, programmable manner without additional required external component...

  16. MEMS in microfluidic channels.

    Energy Technology Data Exchange (ETDEWEB)

    Ashby, Carol Iris Hill; Okandan, Murat; Michalske, Terry A.; Sounart, Thomas L.; Matzke, Carolyn M.

    2004-03-01

    Microelectromechanical systems (MEMS) comprise a new class of devices that include various forms of sensors and actuators. Recent studies have shown that microscale cantilever structures are able to detect a wide range of chemicals, biomolecules or even single bacterial cells. In this approach, cantilever deflection replaces optical fluorescence detection thereby eliminating complex chemical tagging steps that are difficult to achieve with chip-based architectures. A key challenge to utilizing this new detection scheme is the incorporation of functionalized MEMS structures within complex microfluidic channel architectures. The ability to accomplish this integration is currently limited by the processing approaches used to seal lids on pre-etched microfluidic channels. This report describes Sandia's first construction of MEMS instrumented microfluidic chips, which were fabricated by combining our leading capabilities in MEMS processing with our low-temperature photolithographic method for fabricating microfluidic channels. We have explored in-situ cantilevers and other similar passive MEMS devices as a new approach to directly sense fluid transport, and have successfully monitored local flow rates and viscosities within microfluidic channels. Actuated MEMS structures have also been incorporated into microfluidic channels, and the electrical requirements for actuation in liquids have been quantified with an elegant theory. Electrostatic actuation in water has been accomplished, and a novel technique for monitoring local electrical conductivities has been invented.

  17. Pulmonary perfusion ''without ventilation''

    International Nuclear Information System (INIS)

    An 88-yr-old man, with prior left upper lobectomy and phrenic nerve injury, had a ventilation/perfusion lung image. Both wash-in and equilibrium ventilation images showed no radioactive gas in the left lung. Nevertheless, the left lung was perfused. A similar result was obtained on a repeat study 8 days later. Delayed images, during washout, showed some radioactive gas in the left lung. Nearly absent ventilation (but continued perfusion) of that lung might have been related to altered gas dynamics brought about by the prior lobectomy, a submucosal bronchial lesion, phrenic nerve damage, and limited motion of the left part of the diaphragm. This case raises the issue of the degree of ventilation (and the phase relationship between the lungs) required for the entry of radioactive gas into a diseased lung, and the production of a ''reversed ventilation/perfusion mismatch.''

  18. Rapid fabrication of supercapacitor electrodes using bionanoscaffolds in capillary microfluidics

    Science.gov (United States)

    Zang, F.; Chu, S.; Gerasopoulos, K.; Culver, J. N.; Ghodssi, R.

    2015-12-01

    This paper reports the utilization of capillary microfluidics to rapidly create nanostructure-patterned electrodes for energy storage applications. Using patterned photoresist as open-channel capillary microfluidics, Tobacco mosaic virus (TMV) bio-nanoscaffolds suspended in solution are autonomously delivered onto planar gold electrodes over a 1 cm2 area. The TMVs assemble on the electrode and form a dense bio-nanoscaffold layer due to enhanced evaporation-assisted assembly in the open-channel capillary microfluidic device within an hour. The TMV structures are coated with Ni/NiO through electroless plating and thermal oxidation to form supercapacitor electrodes. The galvanostatic charge/discharge cycle showed a 3.6-fold increase in areal capacitance for the nanostructured electrode compared to planar structures.

  19. Tissue culture on a chip: Developmental biology applications of self-organized capillary networks in microfluidic devices.

    Science.gov (United States)

    Miura, Takashi; Yokokawa, Ryuji

    2016-08-01

    Organ culture systems are used to elucidate the mechanisms of pattern formation in developmental biology. Various organ culture techniques have been used, but the lack of microcirculation in such cultures impedes the long-term maintenance of larger tissues. Recent advances in microfluidic devices now enable us to utilize self-organized perfusable capillary networks in organ cultures. In this review, we will overview past approaches to organ culture and current technical advances in microfluidic devices, and discuss possible applications of microfluidics towards the study of developmental biology. PMID:27272910

  20. 3D Printed Multimaterial Microfluidic Valve

    Science.gov (United States)

    Patrick, William G.; Sharma, Sunanda; Kong, David S.; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  1. Plasmonic nanoshell synthesis in microfluidic composite foams.

    Science.gov (United States)

    Duraiswamy, Suhanya; Khan, Saif A

    2010-09-01

    The availability of robust, scalable, and automated nanoparticle manufacturing processes is crucial for the viability of emerging nanotechnologies. Metallic nanoparticles of diverse shape and composition are commonly manufactured by solution-phase colloidal chemistry methods, where rapid reaction kinetics and physical processes such as mixing are inextricably coupled, and scale-up often poses insurmountable problems. Here we present the first continuous flow process to synthesize thin gold "nanoshells" and "nanoislands" on colloidal silica surfaces, which are nanoparticle motifs of considerable interest in plasmonics-based applications. We assemble an ordered, flowing composite foam lattice in a simple microfluidic device, where the lattice cells are alternately aqueous drops containing reagents for nanoparticle synthesis or gas bubbles. Microfluidic foam generation enables precisely controlled reagent dispensing and mixing, and the ordered foam structure facilitates compartmentalized nanoparticle growth. This is a general method for aqueous colloidal synthesis, enabling continuous, inherently digital, scalable, and automated production processes for plasmonic nanomaterials.

  2. 3D Printed Multimaterial Microfluidic Valve.

    Science.gov (United States)

    Keating, Steven J; Gariboldi, Maria Isabella; Patrick, William G; Sharma, Sunanda; Kong, David S; Oxman, Neri

    2016-01-01

    We present a novel 3D printed multimaterial microfluidic proportional valve. The microfluidic valve is a fundamental primitive that enables the development of programmable, automated devices for controlling fluids in a precise manner. We discuss valve characterization results, as well as exploratory design variations in channel width, membrane thickness, and membrane stiffness. Compared to previous single material 3D printed valves that are stiff, these printed valves constrain fluidic deformation spatially, through combinations of stiff and flexible materials, to enable intricate geometries in an actuated, functionally graded device. Research presented marks a shift towards 3D printing multi-property programmable fluidic devices in a single step, in which integrated multimaterial valves can be used to control complex fluidic reactions for a variety of applications, including DNA assembly and analysis, continuous sampling and sensing, and soft robotics. PMID:27525809

  3. Nanostructured microfluidic digestion system for rapid high-performance proteolysis

    OpenAIRE

    Cheng, Gong; Hao, Si-Jie; Yu, Xu; Zheng, Si-Yang

    2015-01-01

    A novel microfluidic protein digestion system with nanostructured and bioactive inner surface was constructed by an easy biomimetic self-assembly strategy for rapid and effective proteolysis in 2 minutes, which is faster than the conventional overnight digestion methods. It is expected that this work would contribute to rapid online digestion in future high-throughput proteomics.

  4. Unconventional microfluidics: expanding the discipline

    OpenAIRE

    Nawaz, Ahmad Ahsan; Mao, Xiaole; Stratton, Zackary S.; Huang, Tony Jun

    2013-01-01

    Since its inception, the discipline of microfluidics has been harnessed for innovations in the biomedicine/chemistry fields—and to great effect. This success has had the natural side-effect of stereotyping microfluidics as a platform for medical diagnostics and miniaturized lab processes. But microfluidics has more to offer. And very recently, some researchers have successfully applied microfluidics to fields outside its traditional domains. In this Focus article, we highlight notable example...

  5. A hybrid microfluidic-vacuum device for direct interfacing with conventional cell culture methods

    Directory of Open Access Journals (Sweden)

    Monuki Edwin S

    2007-09-01

    Full Text Available Abstract Background Microfluidics is an enabling technology with a number of advantages over traditional tissue culture methods when precise control of cellular microenvironment is required. However, there are a number of practical and technical limitations that impede wider implementation in routine biomedical research. Specialized equipment and protocols required for fabrication and setting up microfluidic experiments present hurdles for routine use by most biology laboratories. Results We have developed and validated a novel microfluidic device that can directly interface with conventional tissue culture methods to generate and maintain controlled soluble environments in a Petri dish. It incorporates separate sets of fluidic channels and vacuum networks on a single device that allows reversible application of microfluidic gradients onto wet cell culture surfaces. Stable, precise concentration gradients of soluble factors were generated using simple microfluidic channels that were attached to a perfusion system. We successfully demonstrated real-time optical live/dead cell imaging of neural stem cells exposed to a hydrogen peroxide gradient and chemotaxis of metastatic breast cancer cells in a growth factor gradient. Conclusion This paper describes the design and application of a versatile microfluidic device that can directly interface with conventional cell culture methods. This platform provides a simple yet versatile tool for incorporating the advantages of a microfluidic approach to biological assays without changing established tissue culture protocols.

  6. A microfluidic optical platform for real-time monitoring of pH and oxygen in microfluidic bioreactors and organ-on-chip devices.

    Science.gov (United States)

    Mousavi Shaegh, Seyed Ali; De Ferrari, Fabio; Zhang, Yu Shrike; Nabavinia, Mahboubeh; Binth Mohammad, Niema; Ryan, John; Pourmand, Adel; Laukaitis, Eleanor; Banan Sadeghian, Ramin; Nadhman, Akhtar; Shin, Su Ryon; Nezhad, Amir Sanati; Khademhosseini, Ali; Dokmeci, Mehmet Remzi

    2016-07-01

    There is a growing interest to develop microfluidic bioreactors and organ-on-chip platforms with integrated sensors to monitor their physicochemical properties and to maintain a well-controlled microenvironment for cultured organoids. Conventional sensing devices cannot be easily integrated with microfluidic organ-on-chip systems with low-volume bioreactors for continual monitoring. This paper reports on the development of a multi-analyte optical sensing module for dynamic measurements of pH and dissolved oxygen levels in the culture medium. The sensing system was constructed using low-cost electro-optics including light-emitting diodes and silicon photodiodes. The sensing module includes an optically transparent window for measuring light intensity, and the module could be connected directly to a perfusion bioreactor without any specific modifications to the microfluidic device design. A compact, user-friendly, and low-cost electronic interface was developed to control the optical transducer and signal acquisition from photodiodes. The platform enabled convenient integration of the optical sensing module with a microfluidic bioreactor. Human dermal fibroblasts were cultivated in the bioreactor, and the values of pH and dissolved oxygen levels in the flowing culture medium were measured continuously for up to 3 days. Our integrated microfluidic system provides a new analytical platform with ease of fabrication and operation, which can be adapted for applications in various microfluidic cell culture and organ-on-chip devices. PMID:27648113

  7. Isolated lung perfusion.

    Science.gov (United States)

    Cypel, Marcelo; Keshavjee, Shaf

    2012-01-01

    Isolated lung perfusion (ILP) has been historically used as a method to study basic lung physiologic concepts using animal models. More recently, ILP has been applied in lung transplantation and thoracic oncology. In lung transplantation, ILP has been used to assess physiological integrity of donor lungs after the organ is removed from the donor. This procedure is called Ex vivo Lung Perfusion (EVLP), and it has also been proposed as a method for active treatment and repair of injured unsuitable donor organs ex vivo. In oncology, ILP is an attractive method to deliver high dose chemotherapy to treat pulmonary metastatic disease. Since the lung vasculature is isolated in vivo, this technique is called in vivo lung perfusion (IVLP). This review will focus on the rationale, technical aspects, experimental and clinical experience of EVLP and IVLP. A perspective on the future use of these techniques is described. PMID:22202033

  8. Ex vivo lung perfusion.

    Science.gov (United States)

    Reeb, Jeremie; Cypel, Marcelo

    2016-03-01

    Lung transplantation is an established life-saving therapy for patients with end-stage lung disease. Unfortunately, greater success in lung transplantation is hindered by a shortage of lung donors and the relatively poor early-, mid-, and long-term outcomes associated with severe primary graft dysfunction. Ex vivo lung perfusion has emerged as a modern preservation technique that allows for a more accurate lung assessment and improvement in lung quality. This review outlines the: (i) rationale behind the method; (ii) techniques and protocols; (iii) Toronto ex vivo lung perfusion method; (iv) devices available; and (v) clinical experience worldwide. We also highlight the potential of ex vivo lung perfusion in leading a new era of lung preservation. PMID:26700566

  9. Microprocessor-based integration of microfluidic control for the implementation of automated sensor monitoring and multithreaded optimization algorithms.

    Science.gov (United States)

    Ezra, Elishai; Maor, Idan; Bavli, Danny; Shalom, Itai; Levy, Gahl; Prill, Sebastian; Jaeger, Magnus S; Nahmias, Yaakov

    2015-08-01

    Microfluidic applications range from combinatorial synthesis to high throughput screening, with platforms integrating analog perfusion components, digitally controlled micro-valves and a range of sensors that demand a variety of communication protocols. Currently, discrete control units are used to regulate and monitor each component, resulting in scattered control interfaces that limit data integration and synchronization. Here, we present a microprocessor-based control unit, utilizing the MS Gadgeteer open framework that integrates all aspects of microfluidics through a high-current electronic circuit that supports and synchronizes digital and analog signals for perfusion components, pressure elements, and arbitrary sensor communication protocols using a plug-and-play interface. The control unit supports an integrated touch screen and TCP/IP interface that provides local and remote control of flow and data acquisition. To establish the ability of our control unit to integrate and synchronize complex microfluidic circuits we developed an equi-pressure combinatorial mixer. We demonstrate the generation of complex perfusion sequences, allowing the automated sampling, washing, and calibrating of an electrochemical lactate sensor continuously monitoring hepatocyte viability following exposure to the pesticide rotenone. Importantly, integration of an optical sensor allowed us to implement automated optimization protocols that require different computational challenges including: prioritized data structures in a genetic algorithm, distributed computational efforts in multiple-hill climbing searches and real-time realization of probabilistic models in simulated annealing. Our system offers a comprehensive solution for establishing optimization protocols and perfusion sequences in complex microfluidic circuits. PMID:26227212

  10. Microprocessor-based integration of microfluidic control for the implementation of automated sensor monitoring and multithreaded optimization algorithms.

    Science.gov (United States)

    Ezra, Elishai; Maor, Idan; Bavli, Danny; Shalom, Itai; Levy, Gahl; Prill, Sebastian; Jaeger, Magnus S; Nahmias, Yaakov

    2015-08-01

    Microfluidic applications range from combinatorial synthesis to high throughput screening, with platforms integrating analog perfusion components, digitally controlled micro-valves and a range of sensors that demand a variety of communication protocols. Currently, discrete control units are used to regulate and monitor each component, resulting in scattered control interfaces that limit data integration and synchronization. Here, we present a microprocessor-based control unit, utilizing the MS Gadgeteer open framework that integrates all aspects of microfluidics through a high-current electronic circuit that supports and synchronizes digital and analog signals for perfusion components, pressure elements, and arbitrary sensor communication protocols using a plug-and-play interface. The control unit supports an integrated touch screen and TCP/IP interface that provides local and remote control of flow and data acquisition. To establish the ability of our control unit to integrate and synchronize complex microfluidic circuits we developed an equi-pressure combinatorial mixer. We demonstrate the generation of complex perfusion sequences, allowing the automated sampling, washing, and calibrating of an electrochemical lactate sensor continuously monitoring hepatocyte viability following exposure to the pesticide rotenone. Importantly, integration of an optical sensor allowed us to implement automated optimization protocols that require different computational challenges including: prioritized data structures in a genetic algorithm, distributed computational efforts in multiple-hill climbing searches and real-time realization of probabilistic models in simulated annealing. Our system offers a comprehensive solution for establishing optimization protocols and perfusion sequences in complex microfluidic circuits.

  11. Microfluidics for medical applications

    OpenAIRE

    Berg, van den, T.J.T.P.; Segerink, Loes

    2015-01-01

    Lab-on-a-chip devices for point of care diagnostics have been present in clinics for several years now. Alongside their continual development, research is underway to bring the organs and tissue on-a-chip to the patient, amongst other medical applications of microfluidics. This book provides the reader with a comprehensive review of the latest developments in the application of microfluidics to medicine and is divided into three main sections. The first part of the book discusses the state-of...

  12. Microfluidic Flame Barrier

    Science.gov (United States)

    Mungas, Gregory S. (Inventor); Fisher, David J. (Inventor); Mungas, Christopher (Inventor)

    2013-01-01

    Propellants flow through specialized mechanical hardware that is designed for effective and safe ignition and sustained combustion of the propellants. By integrating a micro-fluidic porous media element between a propellant feed source and the combustion chamber, an effective and reliable propellant injector head may be implemented that is capable of withstanding transient combustion and detonation waves that commonly occur during an ignition event. The micro-fluidic porous media element is of specified porosity or porosity gradient selected to be appropriate for a given propellant. Additionally the propellant injector head design integrates a spark ignition mechanism that withstands extremely hot running conditions without noticeable spark mechanism degradation.

  13. Reverse ventilation--perfusion mismatch

    International Nuclear Information System (INIS)

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients

  14. Extremity perfusion for sarcoma

    NARCIS (Netherlands)

    Hoekstra, Harald Joan

    2008-01-01

    For more than 50 years, the technique of extremity perfusion has been explored in the limb salvage treatment of local, recurrent, and multifocal sarcomas. The "discovery" of tumor necrosis factor-or. in combination with melphalan was a real breakthrough in the treatment of primarily irresectable ext

  15. Simple and cheap microfluidic devices for the preparation of monodisperse emulsions.

    Science.gov (United States)

    Deng, Nan-Nan; Meng, Zhi-Jun; Xie, Rui; Ju, Xiao-Jie; Mou, Chuan-Lin; Wang, Wei; Chu, Liang-Ying

    2011-12-01

    Droplet microfluidics, which can generate monodisperse droplets or bubbles in unlimited numbers, at high speed and with complex structures, have been extensively investigated in chemical and biological fields. However, most current methods for fabricating microfluidic devices, such as glass etching, soft lithography in polydimethylsiloxane (PDMS) or assembly of glass capillaries, are usually either expensive or complicated. Here we report the fabrication of simple and cheap microfluidic devices based on patterned coverslips and microscope glass slides. The advantages of our approach for fabricating microfluidic devices lie in a simple process, inexpensive processing equipment and economical laboratory supplies. The fabricated microfluidic devices feature a flexible design of microchannels, easy spatial patterning of surface wettability, and good chemical compatibility and optical properties. We demonstrate their utilities for generation of monodisperse single and double emulsions with highly controllable flexibility. PMID:22025190

  16. Chemistry in Microfluidic Channels

    Science.gov (United States)

    Chia, Matthew C.; Sweeney, Christina M.; Odom, Teri W.

    2011-01-01

    General chemistry introduces principles such as acid-base chemistry, mixing, and precipitation that are usually demonstrated in bulk solutions. In this laboratory experiment, we describe how chemical reactions can be performed in a microfluidic channel to show advanced concepts such as laminar fluid flow and controlled precipitation. Three sets of…

  17. Surfactants in microfluidics

    NARCIS (Netherlands)

    D. Michler

    2015-01-01

    The rapid development of microfluidic techniques in the last two decades has revolutionized chemical and biological research. This technology has enabled scientists in a manifold of research fields to analyze and synthesize specimens with hither to unreached speed and precision. The number of applic

  18. Basic Microfluidics Theory

    DEFF Research Database (Denmark)

    Svendsen, Winnie Edith

    2015-01-01

    ,000 m−1, which is a huge difference and has a large impact on flow behavior. In this chapter the basic microfluidic theory will be presented, enabling the reader to gain a comprehensive understanding of how liquids behave at the microscale, enough to be able to engage in design of micro systems...

  19. Microfluidics for medical applications

    NARCIS (Netherlands)

    Berg, van den Albert; Segerink, Loes

    2015-01-01

    Lab-on-a-chip devices for point of care diagnostics have been present in clinics for several years now. Alongside their continual development, research is underway to bring the organs and tissue on-a-chip to the patient, amongst other medical applications of microfluidics. This book provides the re

  20. Enzyme detection by microfluidics

    DEFF Research Database (Denmark)

    2013-01-01

    Microfluidic-implemented methods of detecting an enzyme, in particular a DNA-modifying enzyme, are provided, as well as methods for detecting a cell, or a microorganism expressing said enzyme. The enzyme is detected by providing a nucleic acid substrate, which is specifically targeted...... by that enzyme...

  1. DNA Assembly in 3D Printed Fluidics

    OpenAIRE

    Patrick, William G.; Nielsen, Alec A. K.; Keating, Steven J.; Levy, Taylor J.; Che-Wei Wang; Jaime J Rivera; Octavio Mondragón-Palomino; Carr, Peter A.; Voigt, Christopher A.; Neri Oxman; Kong, David S.

    2015-01-01

    The process of connecting genetic parts-DNA assembly-is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly p...

  2. PREFACE: Nano- and microfluidics Nano- and microfluidics

    Science.gov (United States)

    Jacobs, Karin

    2011-05-01

    The field of nano- and microfluidics emerged at the end of the 1990s parallel to the demand for smaller and smaller containers and channels for chemical, biochemical and medical applications such as blood and DNS analysis [1], gene sequencing or proteomics [2, 3]. Since then, new journals and conferences have been launched and meanwhile, about two decades later, a variety of microfluidic applications are on the market. Briefly, 'the small flow becomes mainstream' [4]. Nevertheless, research in nano- and microfluidics is more than downsizing the spatial dimensions. For liquids on the nanoscale, surface and interface phenomena grow in importance and may even dominate the behavior in some systems. The studies collected in this special issue all concentrate on these type of systems and were part ot the priority programme SPP1164 'Nano- and Microfluidics' of the German Science Foundation (Deutsche Forschungsgemeinschaft, DFG). The priority programme was initiated in 2002 by Hendrik Kuhlmann and myself and was launched in 2004. Friction between a moving liquid and a solid wall may, for instance, play an important role so that the usual assumption of a no-slip boundary condition is no longer valid. Likewise, the dynamic deformations of soft objects like polymers, vesicles or capsules in flow arise from the subtle interplay between the (visco-)elasticity of the object and the viscous stresses in the surrounding fluid and, potentially, the presence of structures confining the flow like channels. Consequently, new theories were developed ( see articles in this issue by Münch and Wagner, Falk and Mecke, Bonthuis et al, Finken et al, Almenar and Rauscher, Straube) and experiments were set up to unambiguously demonstrate deviations from bulk, or 'macro', behavior (see articles in this issue by Wolff et al, Vinogradova and Belyaev, Hahn et al, Seemann et al, Grüner and Huber, Müller-Buschbaum et al, Gutsche et al, Braunmüller et al, Laube et al, Brücker, Nottebrock et al

  3. RNA-protein binding kinetics in an automated microfluidic reactor.

    Science.gov (United States)

    Ridgeway, William K; Seitaridou, Effrosyni; Phillips, Rob; Williamson, James R

    2009-11-01

    Microfluidic chips can automate biochemical assays on the nanoliter scale, which is of considerable utility for RNA-protein binding reactions that would otherwise require large quantities of proteins. Unfortunately, complex reactions involving multiple reactants cannot be prepared in current microfluidic mixer designs, nor is investigation of long-time scale reactions possible. Here, a microfluidic 'Riboreactor' has been designed and constructed to facilitate the study of kinetics of RNA-protein complex formation over long time scales. With computer automation, the reactor can prepare binding reactions from any combination of eight reagents, and is optimized to monitor long reaction times. By integrating a two-photon microscope into the microfluidic platform, 5-nl reactions can be observed for longer than 1000 s with single-molecule sensitivity and negligible photobleaching. Using the Riboreactor, RNA-protein binding reactions with a fragment of the bacterial 30S ribosome were prepared in a fully automated fashion and binding rates were consistent with rates obtained from conventional assays. The microfluidic chip successfully combines automation, low sample consumption, ultra-sensitive fluorescence detection and a high degree of reproducibility. The chip should be able to probe complex reaction networks describing the assembly of large multicomponent RNPs such as the ribosome.

  4. Whole-Teflon microfluidic chips

    OpenAIRE

    Ren, Kangning; Dai, Wen; Zhou, Jianhua; Su, Jing; Wu, Hongkai

    2011-01-01

    Although microfluidics has shown exciting potential, its broad applications are significantly limited by drawbacks of the materials used to make them. In this work, we present a convenient strategy for fabricating whole-Teflon microfluidic chips with integrated valves that show outstanding inertness to various chemicals and extreme resistance against all solvents. Compared with other microfluidic materials [e.g., poly(dimethylsiloxane) (PDMS)] the whole-Teflon chip has a few more advantages, ...

  5. Magnetic separation in microfluidic systems

    OpenAIRE

    Smistrup, Kristian; Hansen, Mikkel Fougt; Bruus, Henrik; Tang, Peter Torben; Kruhne, Ulrich Willi Walter

    2007-01-01

    This Ph.D. thesis presents theory, modeling, design, fabrication, experiments and results for microfluidic magnetic separators. A model for magnetic bead movement in a microfluidic channel is presented, and the limits of the model are discussed. The effective magnetic field gradient is defined, and it is argued that it is a good measure, when comparing the performance of magnetic bead separators. It is described how numeric modelling is used to aid the design of microfluidic magnetic separati...

  6. Ex vivo lung perfusion

    OpenAIRE

    Machuca, Tiago N; Cypel, Marcelo

    2014-01-01

    Lung transplantation (LTx) is an established treatment option for eligible patients with end-stage lung disease. Nevertheless, the imbalance between suitable donor lungs available and the increasing number of patients considered for LTx reflects in considerable waitlist mortality. Among potential alternatives to address this issue, ex vivo lung perfusion (EVLP) has emerged as a modern preservation technique that allows for more accurate lung assessment and also improvement of lung function. I...

  7. Microfluidic colloid filtration

    Science.gov (United States)

    Linkhorst, John; Beckmann, Torsten; Go, Dennis; Kuehne, Alexander J. C.; Wessling, Matthias

    2016-03-01

    Filtration of natural and colloidal matter is an essential process in today’s water treatment processes. The colloidal matter is retained with the help of micro- and nanoporous synthetic membranes. Colloids are retained in a “cake layer” - often coined fouling layer. Membrane fouling is the most substantial problem in membrane filtration: colloidal and natural matter build-up leads to an increasing resistance and thus decreasing water transport rate through the membrane. Theoretical models exist to describe macroscopically the hydrodynamic resistance of such transport and rejection phenomena; however, visualization of the various phenomena occurring during colloid retention is extremely demanding. Here we present a microfluidics based methodology to follow filter cake build up as well as transport phenomena occuring inside of the fouling layer. The microfluidic colloidal filtration methodology enables the study of complex colloidal jamming, crystallization and melting processes as well as translocation at the single particle level.

  8. The Microfluidic Jukebox

    Science.gov (United States)

    Tan, Say Hwa; Maes, Florine; Semin, Benoît; Vrignon, Jérémy; Baret, Jean-Christophe

    2014-04-01

    Music is a form of art interweaving people of all walks of life. Through subtle changes in frequencies, a succession of musical notes forms a melody which is capable of mesmerizing the minds of people. With the advances in technology, we are now able to generate music electronically without relying solely on physical instruments. Here, we demonstrate a musical interpretation of droplet-based microfluidics as a form of novel electronic musical instruments. Using the interplay of electric field and hydrodynamics in microfluidic devices, well controlled frequency patterns corresponding to musical tracks are generated in real time. This high-speed modulation of droplet frequency (and therefore of droplet sizes) may also provide solutions that reconciles high-throughput droplet production and the control of individual droplet at production which is needed for many biochemical or material synthesis applications.

  9. Microfluidic redox battery.

    Science.gov (United States)

    Lee, Jin Wook; Goulet, Marc-Antoni; Kjeang, Erik

    2013-07-01

    A miniaturized microfluidic battery is proposed, which is the first membraneless redox battery demonstrated to date. This unique concept capitalizes on dual-pass flow-through porous electrodes combined with stratified, co-laminar flow to generate electrical power on-chip. The fluidic design is symmetric to allow for both charging and discharging operations in forward, reverse, and recirculation modes. The proof-of-concept device fabricated using low-cost materials integrated in a microfluidic chip is shown to produce competitive power levels when operated on a vanadium redox electrolyte. A complete charge/discharge cycle is performed to demonstrate its operation as a rechargeable battery, which is an important step towards providing sustainable power to lab-on-a-chip and microelectronic applications. PMID:23712370

  10. Microfluidic redox battery.

    Science.gov (United States)

    Lee, Jin Wook; Goulet, Marc-Antoni; Kjeang, Erik

    2013-07-01

    A miniaturized microfluidic battery is proposed, which is the first membraneless redox battery demonstrated to date. This unique concept capitalizes on dual-pass flow-through porous electrodes combined with stratified, co-laminar flow to generate electrical power on-chip. The fluidic design is symmetric to allow for both charging and discharging operations in forward, reverse, and recirculation modes. The proof-of-concept device fabricated using low-cost materials integrated in a microfluidic chip is shown to produce competitive power levels when operated on a vanadium redox electrolyte. A complete charge/discharge cycle is performed to demonstrate its operation as a rechargeable battery, which is an important step towards providing sustainable power to lab-on-a-chip and microelectronic applications.

  11. Animal microsurgery using microfluidics

    OpenAIRE

    Stirman, Jeffrey N.; Harker, Bethany; Lu, Hang; Crane, Matthew M.

    2013-01-01

    Small multicellular genetic organisms form a central part of modern biological research. Using these small organisms provides significant advantages in genetic tractability, manipulation, lifespan and cost. Although the small size is generally advantageous, it can make procedures such as surgeries both time consuming and labor intensive. Over the past few years there have been dramatic improvements in microfluidic technologies that enable significant improvements in microsurgery and interroga...

  12. Microfluidics in radiopharmaceutical chemistry

    International Nuclear Information System (INIS)

    The increased demand for molecular imaging tracers useful in assessing and monitoring diseases has stimulated research towards more efficient and flexible radiosynthetic routes, including newer technologies. The traditional vessel-based approach suffers from limitations concerning flexibility, reagent mass needed, hardware requirements, large number of connections and valves, repetitive cleaning procedures and overall big footprint to be shielded from radiation. For these reasons, several research groups have started to investigate the application of the fast growing field of microfluidic chemistry to radiosynthetic procedures. After the first report in 2004, many scientific papers have been published and demonstrated the potential for increased process yields, reduced reagent use, improved flexibility and general ease of setup. This review will address definitions occurring in microfluidics as well as analyze the different approaches under two macro-categories: microvessel and microchannel. In this perspective, several works will be collected, involving the use of positron emitting species (11C, 18F, 64Cu) and the fewer examples of gamma emitting radionuclides (99mTc, 125/131I). New directions in microfluidic research applied to PET radiochemistry, future developments and challenges are also discussed. -- Graphical abstract: Display Omitted

  13. Engineering anastomosis between living capillary networks and endothelial cell-lined microfluidic channels.

    Science.gov (United States)

    Wang, Xiaolin; Phan, Duc T T; Sobrino, Agua; George, Steven C; Hughes, Christopher C W; Lee, Abraham P

    2016-01-21

    This paper reports a method for generating an intact and perfusable microvascular network that connects to microfluidic channels without appreciable leakage. This platform incorporates different stages of vascular development including vasculogenesis, endothelial cell (EC) lining, sprouting angiogenesis, and anastomosis in sequential order. After formation of a capillary network inside the tissue chamber via vasculogenesis, the adjacent microfluidic channels are lined with a monolayer of ECs, which then serve as the high-pressure input ("artery") and low pressure output ("vein") conduits. To promote a tight interconnection between the artery/vein and the capillary network, sprouting angiogenesis is induced, which promotes anastomosis of the vasculature inside the tissue chamber with the EC lining along the microfluidic channels. Flow of fluorescent microparticles confirms the perfusability of the lumenized microvascular network, and minimal leakage of 70 kDa FITC-dextran confirms physiologic tightness of the EC junctions and completeness of the interconnections between artery/vein and the capillary network. This versatile device design and its robust construction methodology establish a physiological transport model of interconnected perfused vessels from artery to vascularized tissue to vein. The system has utility in a wide range of organ-on-a-chip applications as it enables the physiological vascular interconnection of multiple on-chip tissue constructs that can serve as disease models for drug screening. PMID:26616908

  14. A microfluidic chip with a U-shaped microstructure array for multicellular spheroid formation, culturing and analysis

    International Nuclear Information System (INIS)

    Multicellular spheroids (MCS), formed by self-assembly of single cells, are commonly used as a three-dimensional cell culture model to bridge the gap between in vitro monolayer culture and in vivo tissues. However, current methods for MCS generation and analysis still suffer drawbacks such as being labor-intensive and of poor controllability, and are not suitable for high-throughput applications. This study demonstrates a novel microfluidic chip to facilitate MCS formation, culturing and analysis. The chip contains an array of U-shaped microstructures fabricated by photopolymerizing the poly(ethylene glycol) diacrylate hydrogel through defining the ultraviolet light exposure pattern with a photomask. The geometry of the U-shaped microstructures allowed trapping cells into the pocket through the actions of fluid flow and the force of gravity. The hydrogel is non-adherent for cells, promoting the formation of MCS. Its permselective property also facilitates exchange of nutrients and waste for MCS, while providing protection of MCS from shearing stress during the medium perfusion. Heterotypic MCS can be formed easily by manipulating the cell trapping steps. Subsequent drug susceptibility analysis and long-term culture could also be achieved within the same chip. This MCS formation and culture platform can be used as a micro-scale bioreactor and applied in many cell biology and drug testing studies. (paper)

  15. Perfusion based cell culture chips

    DEFF Research Database (Denmark)

    Heiskanen, Arto; Emnéus, Jenny; Dufva, Martin

    2010-01-01

    Performing cell culture in miniaturized perfusion chambers gives possibilities to experiment with cells under near in vivo like conditions. In contrast to traditional batch cultures, miniaturized perfusion systems provide precise control of medium composition, long term unattended cultures...... and tissue like structuring of the cultures. However, as this chapter illustrates, many issues remain to be identified regarding perfusion cell culture such as design, material choice and how to use these systems before they will be widespread amongst biomedical researchers....

  16. Reverse ventilation--perfusion mismatch

    Energy Technology Data Exchange (ETDEWEB)

    Palmaz, J.C.; Barnett, C.A.; Reich, S.B.; Krumpe, P.E.; Farrer, P.A.

    1984-01-01

    Patients having lobar airway obstruction or consolidation usually have decreases of both ventilation and perfusion on lung scans. We report three patients in whom hypoxic vasoconstriction was apparently incomplete, resulting in a ''reversed'' ventilation-perfusion mismatch. Perfusion of the hypoxic lobe on the radionuclide scan was associated with metabolic alkalosis, pulmonary venous and pulmonary arterial hypertension in these patients.

  17. System-level simulation of liquid filling in microfluidic chips.

    Science.gov (United States)

    Song, Hongjun; Wang, Yi; Pant, Kapil

    2011-06-01

    Liquid filling in microfluidic channels is a complex process that depends on a variety of geometric, operating, and material parameters such as microchannel geometry, flow velocity∕pressure, liquid surface tension, and contact angle of channel surface. Accurate analysis of the filling process can provide key insights into the filling time, air bubble trapping, and dead zone formation, and help evaluate trade-offs among the various design parameters and lead to optimal chip design. However, efficient modeling of liquid filling in complex microfluidic networks continues to be a significant challenge. High-fidelity computational methods, such as the volume of fluid method, are prohibitively expensive from a computational standpoint. Analytical models, on the other hand, are primarily applicable to idealized geometries and, hence, are unable to accurately capture chip level behavior of complex microfluidic systems. This paper presents a parametrized dynamic model for the system-level analysis of liquid filling in three-dimensional (3D) microfluidic networks. In our approach, a complex microfluidic network is deconstructed into a set of commonly used components, such as reservoirs, microchannels, and junctions. The components are then assembled according to their spatial layout and operating rationale to achieve a rapid system-level model. A dynamic model based on the transient momentum equation is developed to track the liquid front in the microchannels. The principle of mass conservation at the junction is used to link the fluidic parameters in the microchannels emanating from the junction. Assembly of these component models yields a set of differential and algebraic equations, which upon integration provides temporal information of the liquid filling process, particularly liquid front propagation (i.e., the arrival time). The models are used to simulate the transient liquid filling process in a variety of microfluidic constructs and in a multiplexer, representing a

  18. Ventilation-perfusion emission tomography

    International Nuclear Information System (INIS)

    The ventilation-perfusion research with SPECT is discussed. With SPECT three dimensional activity distribution can be made. Perfusion scintigraphy can be done with 99m-Tc labeled particles, ventilation scintigraphy can only be done with 81m-Kr or labeled aerosols. A disadvantage in using 99m-Tc is interference with labeled perfusion tracers. For a reliable quantification the ventilation and perfusion pictures should be registered at the same time, the energies of both tracers must lay far apart and in quantification of regional ventilation from 81m-Kr activity distribution correction must be made for differences in regional specific ventilation. 4 refs.; 3 figs

  19. Centrifugal microfluidics for biomedical applications.

    Science.gov (United States)

    Gorkin, Robert; Park, Jiwoon; Siegrist, Jonathan; Amasia, Mary; Lee, Beom Seok; Park, Jong-Myeon; Kim, Jintae; Kim, Hanshin; Madou, Marc; Cho, Yoon-Kyoung

    2010-07-21

    The centrifugal microfluidic platform has been a focus of academic and industrial research efforts for almost 40 years. Primarily targeting biomedical applications, a range of assays have been adapted on the system; however, the platform has found limited commercial success as a research or clinical tool. Nonetheless, new developments in centrifugal microfluidic technologies have the potential to establish wide-spread utilization of the platform. This paper presents an in-depth review of the centrifugal microfluidic platform, while highlighting recent progress in the field and outlining the potential for future applications. An overview of centrifugal microfluidic technologies is presented, including descriptions of advantages of the platform as a microfluidic handling system and the principles behind centrifugal fluidic manipulation. The paper also discusses a history of significant centrifugal microfluidic platform developments with an explanation of the evolution of the platform as it pertains to academia and industry. Lastly, we review the few centrifugal microfluidic-based sample-to-answer analysis systems shown to date and examine the challenges to be tackled before the centrifugal platform can be more broadly accepted as a new diagnostic platform. In particular, fully integrated, easy to operate, inexpensive and accurate microfluidic tools in the area of in vitro nucleic acid diagnostics are discussed.

  20. Path to Low Cost Microfluidics

    CERN Document Server

    Govyadinov, Alexander N; Kornilovitch, Pavel; Markel, David

    2016-01-01

    The paper describes a novel concept for a low cost microfluidic platform utilizing materials and processes used in low cost thermal inkjet printing. The concept re-purposes the jetting elements to create pumps, mixers, and valves all necessary components for the transport of fluids in a broad range of microfluidic applications.

  1. Microfluidic partitioning of the extracellular space around single cardiac myocytes.

    Science.gov (United States)

    Klauke, Norbert; Smith, Godfrey L; Cooper, Jonathan M

    2007-02-01

    This paper describes the partitioning of the extracellular space around an electrically activated single cardiac myocyte, constrained within a microfluidic device. Central to this new method is the production of a hydrophobic gap-structure, which divides the extracellular space into two distinct microfluidic pools. The content of these pools was controlled using a pair of concentric automated pipets (subsequently called "dual superfusion pipet"), each providing the ability to dispense (i.e., the source, inner pipet) and aspirate (the sink, outer pipet) a buffer solution (perfusate) into each of the two pools. For rapid solution switching around the cell, additional dual superfusion pipets were inserted into the microchannel for defined time periods using a piezostepper, enabling us to add a test solution, such as a drug. Three distinct areas of the cell were manipulated, namely, the microfluidic environment, the cellular membrane, and the intracellular space. Planar integrated microelectrodes enabled the electrical stimulation of the cardiomyocyte and the recording of the evoked action potential. The device was mounted on an inverted microscope to allow simultaneous sarcomere length and epifluorescence measurements during evoked electrical activity, including, for example, the response of the stimulated end of the cardiac myocyte in comparison with the untreated cell end.

  2. Acoustofluidics 1: Governing equations in microfluidics

    DEFF Research Database (Denmark)

    Bruus, Henrik

    2011-01-01

    Governing equations for microfluidics and basic flow solutions are presented. Equivalent circuit modeling for determining flow rates in microfluidic networks is introduced.......Governing equations for microfluidics and basic flow solutions are presented. Equivalent circuit modeling for determining flow rates in microfluidic networks is introduced....

  3. Microfluidic Technology in Vascular Research

    Directory of Open Access Journals (Sweden)

    A. D. van der Meer

    2009-01-01

    Full Text Available 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.

  4. MICROFLUIDIC COMPONENT CAPABLE OF SELF-SEALING

    DEFF Research Database (Denmark)

    2009-01-01

    A microfluidic component (100) for building a microfluidic system is provided. The microfluidic component (100) can be mounted on a microf luidic breadboard (202) in a manner that allows it to be connected to other microfluidic components (204, 206) without the requirement of additional devices....... The microfluidic component (100) comprises at least one flexible tube piece (102) for transporting a fluid. The microfluidic component (100) also comprises means for applying and maintaining pressure (104) between the flexible tube piece (102) and a tube piece (208, 210) housed in another microfluidic...

  5. Measuring myocardial perfusion

    DEFF Research Database (Denmark)

    Qayyum, A A; Kastrup, J

    2015-01-01

    -pass of non-ionic and ionic contrast agents, respectively. Absolute quantification with CMR has yet to be established in routine clinical practice, while CT has yet to prove its diagnostic and prognostic value. The upcoming years may change the way we diagnose and treat patients suspected of having CAD......Recently, focus has changed from anatomical assessment of coronary arteries towards functional testing to evaluate the effect of stenosis on the myocardium before intervention. Besides positron-emission tomography (PET), cardiac MRI (CMR), and cardiac CT are able to measure myocardial perfusion...

  6. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill;

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...

  7. Lung Ventilation/Perfusion Scan

    Science.gov (United States)

    ... two types of scans: ventilation and perfusion. The ventilation scan shows where air flows in your lungs. The perfusion scan shows where blood flows in your lungs. Both scans use radioisotopes (a low-risk radioactive substance). For the ventilation scan, you ...

  8. Microfluidic Scintillation Detectors

    CERN Multimedia

    Microfluidic scintillation detectors are devices of recent introduction for the detection of high energy particles, developed within the EP-DT group at CERN. Most of the interest for such technology comes from the use of liquid scintillators, which entails the possibility of changing the active material in the detector, leading to an increased radiation resistance. This feature, together with the high spatial resolution and low thickness deriving from the microfabrication techniques used to manufacture such devices, is desirable not only in instrumentation for high energy physics experiments but also in medical detectors such as beam monitors for hadron therapy.

  9. Spatial manipulation with microfluidics

    Directory of Open Access Journals (Sweden)

    Benjamin eLin

    2015-04-01

    Full Text Available Biochemical gradients convey information through space, time, and concentration, and are ultimately capable of spatially resolving distinct cellular phenotypes, such as differentiation, proliferation, and migration. How these gradients develop, evolve, and function during development, homeostasis, and various disease states is a subject of intense interest across a variety of disciplines. Microfluidic technologies have become essential tools for investigating gradient sensing in vitro due to their ability to precisely manipulate fluids on demand in well controlled environments at cellular length scales. This minireview will highlight their utility for studying gradient sensing along with relevant applications to biology.

  10. Microfluidic Cell Culture Device

    Science.gov (United States)

    Takayama, Shuichi (Inventor); Cabrera, Lourdes Marcella (Inventor); Heo, Yun Seok (Inventor); Smith, Gary Daniel (Inventor)

    2014-01-01

    Microfluidic devices for cell culturing and methods for using the same are disclosed. One device includes a substrate and membrane. The substrate includes a reservoir in fluid communication with a passage. A bio-compatible fluid may be added to the reservoir and passage. The reservoir is configured to receive and retain at least a portion of a cell mass. The membrane acts as a barrier to evaporation of the bio-compatible fluid from the passage. A cover fluid may be added to cover the bio-compatible fluid to prevent evaporation of the bio-compatible fluid.

  11. CT Perfusion: applications in neuroimaging

    International Nuclear Information System (INIS)

    Full text: CT perfusion is a relatively new imaging technique that tracks the passage of a bolus dose of iodinated contrast medium through the intracranial vasculature and tissues. It allows both qualitative and quantitative analysis of cerebral perfusion parameters. The most common and significant neurological diseases (eg stroke and subarachnoid haemorrhage) can have a potentially significant impact on cerebral perfusion. Accurate analysis of cerebral perfusion affords a greater understanding of these diseases and provides further information regarding the timing and effects of intervention.We present a synopsis of our work to date on the clinical applications of CT perfusion in a variety of neurological disorders. A GE High Speed Cti system (GE Medical Systems, Milwaukee, US) with Perfusion 2 software (GE Medical System, Milwaukee, US) was used to obtain cerebral perfusion parameter maps and quantitative values of perfusion in specific regions of interest using an Advantage Windows 4.0 workstation (GE Medical Systems, Milwaukee, US). Depending on the clinical scenario, between one and three levels of the brain were examined to survey the appropriate level of interest. For example, patients with subarachnoid haemorrhage had imaging through the basal ganglia and the watershed areas. Other areas where we have applied this technique are tumour imaging, brain death and chronic cerebral ischaemia. CT perfusion is a widely applicable technique that is both quantitative and reproducible in a wide variety of clinical settings. It can be performed as part of the routine imaging of patients, and may be used in patients who are moderately un-cooperative, as the study takes little time to perform. CT perfusion shows significant promise in improving our understanding of many neurovascular conditions and in monitoring the effects of clinical interventions. Copyright (2002) Blackwell Science Pty Ltd

  12. Microfluidic fuel cells and batteries

    CERN Document Server

    Kjeang, Erik

    2014-01-01

    Microfluidic fuel cells and batteries represent a special type of electrochemical power generators that can be miniaturized and integrated in a microfluidic chip. Summarizing the initial ten years of research and development in this emerging field, this SpringerBrief is the first book dedicated to microfluidic fuel cell and battery technology for electrochemical energy conversion and storage. Written at a critical juncture, where strategically applied research is urgently required to seize impending technology opportunities for commercial, analytical, and educational utility, the intention is

  13. The upcoming 3D-printing revolution in microfluidics.

    Science.gov (United States)

    Bhattacharjee, Nirveek; Urrios, Arturo; Kang, Shawn; Folch, Albert

    2016-05-21

    In the last two decades, the vast majority of microfluidic systems have been built in poly(dimethylsiloxane) (PDMS) by soft lithography, a technique based on PDMS micromolding. A long list of key PDMS properties have contributed to the success of soft lithography: PDMS is biocompatible, elastomeric, transparent, gas-permeable, water-impermeable, fairly inexpensive, copyright-free, and rapidly prototyped with high precision using simple procedures. However, the fabrication process typically involves substantial human labor, which tends to make PDMS devices difficult to disseminate outside of research labs, and the layered molding limits the 3D complexity of the devices that can be produced. 3D-printing has recently attracted attention as a way to fabricate microfluidic systems due to its automated, assembly-free 3D fabrication, rapidly decreasing costs, and fast-improving resolution and throughput. Resins with properties approaching those of PDMS are being developed. Here we review past and recent efforts in 3D-printing of microfluidic systems. We compare the salient features of PDMS molding with those of 3D-printing and we give an overview of the critical barriers that have prevented the adoption of 3D-printing by microfluidic developers, namely resolution, throughput, and resin biocompatibility. We also evaluate the various forces that are persuading researchers to abandon PDMS molding in favor of 3D-printing in growing numbers. PMID:27101171

  14. A Droplet Microfluidic Platform for Automating Genetic Engineering.

    Science.gov (United States)

    Gach, Philip C; Shih, Steve C C; Sustarich, Jess; Keasling, Jay D; Hillson, Nathan J; Adams, Paul D; Singh, Anup K

    2016-05-20

    We present a water-in-oil droplet microfluidic platform for transformation, culture and expression of recombinant proteins in multiple host organisms including bacteria, yeast and fungi. The platform consists of a hybrid digital microfluidic/channel-based droplet chip with integrated temperature control to allow complete automation and integration of plasmid addition, heat-shock transformation, addition of selection medium, culture, and protein expression. The microfluidic format permitted significant reduction in consumption (100-fold) of expensive reagents such as DNA and enzymes compared to the benchtop method. The chip contains a channel to continuously replenish oil to the culture chamber to provide a fresh supply of oxygen to the cells for long-term (∼5 days) cell culture. The flow channel also replenished oil lost to evaporation and increased the number of droplets that could be processed and cultured. The platform was validated by transforming several plasmids into Escherichia coli including plasmids containing genes for fluorescent proteins GFP, BFP and RFP; plasmids with selectable markers for ampicillin or kanamycin resistance; and a Golden Gate DNA assembly reaction. We also demonstrate the applicability of this platform for transformation in widely used eukaryotic organisms such as Saccharomyces cerevisiae and Aspergillus niger. Duration and temperatures of the microfluidic heat-shock procedures were optimized to yield transformation efficiencies comparable to those obtained by benchtop methods with a throughput up to 6 droplets/min. The proposed platform offers potential for automation of molecular biology experiments significantly reducing cost, time and variability while improving throughput. PMID:26830031

  15. The upcoming 3D-printing revolution in microfluidics.

    Science.gov (United States)

    Bhattacharjee, Nirveek; Urrios, Arturo; Kang, Shawn; Folch, Albert

    2016-05-21

    In the last two decades, the vast majority of microfluidic systems have been built in poly(dimethylsiloxane) (PDMS) by soft lithography, a technique based on PDMS micromolding. A long list of key PDMS properties have contributed to the success of soft lithography: PDMS is biocompatible, elastomeric, transparent, gas-permeable, water-impermeable, fairly inexpensive, copyright-free, and rapidly prototyped with high precision using simple procedures. However, the fabrication process typically involves substantial human labor, which tends to make PDMS devices difficult to disseminate outside of research labs, and the layered molding limits the 3D complexity of the devices that can be produced. 3D-printing has recently attracted attention as a way to fabricate microfluidic systems due to its automated, assembly-free 3D fabrication, rapidly decreasing costs, and fast-improving resolution and throughput. Resins with properties approaching those of PDMS are being developed. Here we review past and recent efforts in 3D-printing of microfluidic systems. We compare the salient features of PDMS molding with those of 3D-printing and we give an overview of the critical barriers that have prevented the adoption of 3D-printing by microfluidic developers, namely resolution, throughput, and resin biocompatibility. We also evaluate the various forces that are persuading researchers to abandon PDMS molding in favor of 3D-printing in growing numbers.

  16. A Droplet Microfluidic Platform for Automating Genetic Engineering.

    Science.gov (United States)

    Gach, Philip C; Shih, Steve C C; Sustarich, Jess; Keasling, Jay D; Hillson, Nathan J; Adams, Paul D; Singh, Anup K

    2016-05-20

    We present a water-in-oil droplet microfluidic platform for transformation, culture and expression of recombinant proteins in multiple host organisms including bacteria, yeast and fungi. The platform consists of a hybrid digital microfluidic/channel-based droplet chip with integrated temperature control to allow complete automation and integration of plasmid addition, heat-shock transformation, addition of selection medium, culture, and protein expression. The microfluidic format permitted significant reduction in consumption (100-fold) of expensive reagents such as DNA and enzymes compared to the benchtop method. The chip contains a channel to continuously replenish oil to the culture chamber to provide a fresh supply of oxygen to the cells for long-term (∼5 days) cell culture. The flow channel also replenished oil lost to evaporation and increased the number of droplets that could be processed and cultured. The platform was validated by transforming several plasmids into Escherichia coli including plasmids containing genes for fluorescent proteins GFP, BFP and RFP; plasmids with selectable markers for ampicillin or kanamycin resistance; and a Golden Gate DNA assembly reaction. We also demonstrate the applicability of this platform for transformation in widely used eukaryotic organisms such as Saccharomyces cerevisiae and Aspergillus niger. Duration and temperatures of the microfluidic heat-shock procedures were optimized to yield transformation efficiencies comparable to those obtained by benchtop methods with a throughput up to 6 droplets/min. The proposed platform offers potential for automation of molecular biology experiments significantly reducing cost, time and variability while improving throughput.

  17. Engineering particle morphology with microfluidic droplets

    Science.gov (United States)

    Kang, Zhanxiao; Kong, Tiantian; Lei, Leyan; Zhu, Pingan; Tian, Xiaowei; Wang, Liqiu

    2016-07-01

    The controlled generation of microparticles with non-spherical features is of increasing importance. Such particles are useful for fundamental studies in areas such as self-assembly, as well as biomedical applications from drug carriers to photonic devices. We propose a simple model that captures the dominating factors controlling the size and morphology of non-spherical particles from phase separated droplets. The validity of our model is verified by comparing the generated non-spherical microparticles by droplet microfluidics. This simple relationship between the dominating factors and the final morphologies enables the production of non-spherical particles with well-defined shapes and tightly-controlled dimensions for a variety of applications from drug delivery vehicles to structural materials.

  18. An easy-to-use microfluidic interconnection system to create quick and reversibly interfaced simple microfluidic devices

    Science.gov (United States)

    Pfreundt, Andrea; Brandt Andersen, Karsten; Dimaki, Maria; Svendsen, Winnie E.

    2015-11-01

    The presented microfluidic interconnection system provides an alternative for the individual interfacing of simple microfluidic devices fabricated in polymers such as polymethylmethacrylate, polycarbonate and cyclic olefin polymer. A modification of the device inlet enables the direct attachment of tubing (such as polytetrafluoroethylene tubing) secured and sealed by using a small plug, without the need for additional assembly, glue or o-rings. This provides a very clean connection that does not require additional, potentially incompatible, materials. The tightly sealed connection can withstand pressures above 250 psi and therefore supports applications with high flow rates or highly viscous fluids. The ease of incorporation, configuration, fabrication and use make this interconnection system ideal for the rapid prototyping of simple microfluidic devices or other integrated systems that require microfluidic interfaces. It provides a valuable addition to the toolbox of individual and small arrays of connectors suitable for micromachined or template-based injection molded devices since it does not require protruding, threaded or glued modifications on the inlet and avoids bulky and expensive fittings.

  19. Solvent resistant microfluidic DNA synthesizer.

    Science.gov (United States)

    Huang, Yanyi; Castrataro, Piero; Lee, Cheng-Chung; Quake, Stephen R

    2007-01-01

    We fabricated a microfluidic DNA synthesizer out of perfluoropolyether (PFPE), an elastomer with excellent chemical compatibility which makes it possible to perform organic chemical reactions, and synthesized 20-mer oligonucleotides on chip. PMID:17180201

  20. Microfluidic Multichannel Flow Cytometer Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a "Microfluidic Multichannel Flow Cytometer." Several novel concepts are integrated to produce the final design, which is compatible with...

  1. Passive microfluidic array card and reader

    Energy Technology Data Exchange (ETDEWEB)

    Dugan, Lawrence Christopher (Modesto, CA); Coleman, Matthew A. (Oakland, CA)

    2011-08-09

    A microfluidic array card and reader system for analyzing a sample. The microfluidic array card includes a sample loading section for loading the sample onto the microfluidic array card, a multiplicity of array windows, and a transport section or sections for transporting the sample from the sample loading section to the array windows. The microfluidic array card reader includes a housing, a receiving section for receiving the microfluidic array card, a viewing section, and a light source that directs light to the array window of the microfluidic array card and to the viewing section.

  2. Reconfigurable microfluidic platform in ice

    OpenAIRE

    Varejka, M.

    2008-01-01

    Microfluidic devices are popular tools in the biotechnology industry where they provide smaller reagent requirements, high speed of analysis and the possibility for automation. The aim of the project is to make a flexible biocompatible microfluidic platform adapted to different specific applications, mainly analytical and separations which parameters and configuration can be changed multiple times by changing corresponding computer programme. The current project has been sup...

  3. Microfluidics - Sorting particles with light

    DEFF Research Database (Denmark)

    Glückstad, J.

    2004-01-01

    Microfluidic systems have great potential to perform complex chemical and biological processing and analysis on a single disposable chip. That goal is now a step closer with the demonstration of an efficient all-optical particle sorter.......Microfluidic systems have great potential to perform complex chemical and biological processing and analysis on a single disposable chip. That goal is now a step closer with the demonstration of an efficient all-optical particle sorter....

  4. Digital Microfluidic Cell Culture.

    Science.gov (United States)

    Ng, Alphonsus H C; Li, Bingyu Betty; Chamberlain, M Dean; Wheeler, Aaron R

    2015-01-01

    Digital microfluidics (DMF) is a droplet-based liquid-handling technology that has recently become popular for cell culture and analysis. In DMF, picoliter- to microliter-sized droplets are manipulated on a planar surface using electric fields, thus enabling software-reconfigurable operations on individual droplets, such as move, merge, split, and dispense from reservoirs. Using this technique, multistep cell-based processes can be carried out using simple and compact instrumentation, making DMF an attractive platform for eventual integration into routine biology workflows. In this review, we summarize the state-of-the-art in DMF cell culture, and describe design considerations, types of DMF cell culture, and cell-based applications of DMF. PMID:26643019

  5. Image-guided precision manipulation of cells and nanoparticles in microfluidics

    Science.gov (United States)

    Cummins, Zachary

    Manipulation of single cells and particles is important to biology and nanotechnology. Our electrokinetic (EK) tweezers manipulate objects in simple microfluidic devices using gentle fluid and electric forces under vision-based feedback control. In this dissertation, I detail a user-friendly implementation of EK tweezers that allows users to select, position, and assemble cells and nanoparticles. This EK system was used to measure attachment forces between living breast cancer cells, trap single quantum dots with 45 nm accuracy, build nanophotonic circuits, and scan optical properties of nanowires. With a novel multi-layer microfluidic device, EK was also used to guide single microspheres along complex 3D trajectories. The schemes, software, and methods developed here can be used in many settings to precisely manipulate most visible objects, assemble objects into useful structures, and improve the function of lab-on-a-chip microfluidic systems.

  6. Development of a pneumatically driven active cover lid for multi-well microplates for use in perfusion three-dimensional cell culture

    Science.gov (United States)

    Huang, Song-Bin; Chou, Dean; Chang, Yu-Han; Li, Ke-Cing; Chiu, Tzu-Keng; Ventikos, Yiannis; Wu, Min-Hsien

    2015-12-01

    Before microfluidic-based cell culture models can be practically utilized for bioassays, there is a need for a transitional cell culture technique that can improve conventional cell culture models. To address this, a hybrid cell culture system integrating an active cover lid and a multi-well microplate was proposed to achieve perfusion 3-D cell culture. In this system, a microfluidic-based pneumatically-driven liquid transport mechanism was integrated into the active cover lid to realize 6-unit culture medium perfusion. Experimental results revealed that the flow of culture medium could be pneumatically driven in a flow-rate uniform manner. We used the system to successfully perform a perfusion 3-D cell culture of mesenchymal stem cells (MSCs) for up to 16 days. Moreover, we investigated the effects of various cell culture models on the physiology of MSCs. The physiological nature of MSCs can vary with respect to the cell culture model used. Using the perfusion 3-D cell culture format might affect the proliferation and osteogenic differentiation of MSCs. Overall, we have developed a cell culture system that can achieve multi-well microplate-based perfusion 3-D cell culture in an efficient, cost-effective, and user-friendly manner. These features could facilitate the widespread application of perfusion cell culture models for cell-based assays.

  7. Multi-detector CT perfusion

    Directory of Open Access Journals (Sweden)

    Ashraf M. Enite

    2016-09-01

    Conclusion: CTP is a promising non-invasive technique assessing the efficacy, predicting early response to local treatment therapies and monitoring tumor recurrence. It assesses the degree of post therapy tumor perfusion especially the degree of arterialization.

  8. An adaptable stage perfusion incubator for the controlled cultivation of C2C12 myoblasts.

    Science.gov (United States)

    Kurth, Felix; Franco-Obregón, Alfredo; Bärtschi, Christoph A; Dittrich, Petra S

    2015-01-01

    Here we present a stage perfusion incubation system that allows for the cultivation of mammalian cells within PDMS microfluidic devices for long-term microscopic examination and analysis. The custom-built stage perfusion incubator is adaptable to any x-y microscope stage and is enabled for temperature, gas and humidity control as well as equipped with chip and tubing holder. The applied double-layered microfluidic chip allows the predetermined positioning and concentration of cells while the gas permeable PDMS material facilitates pH control via CO2 levels throughout the chip. We demonstrate the functionality of this system by culturing C2C12 murine myoblasts in buffer free medium within its confines for up to 26 hours. We moreover demonstrated the system's compatibility with various chip configurations, other cells lines (HEK-293 cells) and for longer-term culturing. The cost-efficient system are applicable for any type of PDMS-based cell culture system. Detailed technical drawings and specification to reproduce this perfusion incubation system is provided in the ESI.

  9. Ex-vivo lung perfusion.

    Science.gov (United States)

    Van Raemdonck, Dirk; Neyrinck, Arne; Cypel, Marcelo; Keshavjee, Shaf

    2015-06-01

    This review outlines the new and promising technique of ex vivo lung perfusion and its clinical potential to increase the number of transplantable lungs and to improve the early and late outcome after transplantation. The rationale, the experimental background, the technique and protocols, and available devices for ex vivo lung perfusion are discussed. The current clinical experience worldwide and ongoing clinical trials are reviewed. PMID:24629039

  10. A Supramolecular Sensing Platform for Phosphate Anions and an Anthrax Biomarker in a Microfluidic Device

    NARCIS (Netherlands)

    Eker, Bilge; Yilmaz, Mahmut Deniz; Schlautmann, Stefan; Gardeniers, Johannes G.E.; Huskens, Jurriaan

    2011-01-01

    A supramolecular platform based on self-assembled monolayers (SAMs) has been implemented in a microfluidic device. The system has been applied for the sensing of two different analyte types: biologically relevant phosphate anions and aromatic carboxylic acids, which are important for anthrax detecti

  11. CAD of myocardial perfusion

    Science.gov (United States)

    Storm, Corstiaan J.; Slump, Cornelis H.

    2007-03-01

    Our purpose is in the automated evaluation of the physiological relevance of lesions in coronary angiograms. We aim to extract as much as possible quantitative information about the physiological condition of the heart from standard angiographic image sequences. Coronary angiography is still the gold standard for evaluating and diagnosing coronary abnormalities as it is able to locate precisely the coronary artery lesions. The dimensions of the stenosis can be assessed nowadays successfully with image processing based Quantitative Coronary Angiography (QCA) techniques. Our purpose is to assess the clinical relevance of the pertinent stenosis. We therefore analyze the myocardial perfusion as revealed in standard angiographic image sequences. In a Region-of-Interest (ROI) on the angiogram (without an overlaying major blood vessel) the contrast is measured as a function of time (the so-called time-density curve). The required hyperemic state of exercise is induced artificially by the injection of a vasodilator drug e.g. papaverine. In order to minimize motion artifacts we select based on the recorded ECG signal end-diastolic images in both a basal and a hyperemic run in the same projection to position the ROI. We present the development of the algorithms together with results of a small study of 20 patients which have been catheterized following the standard protocol.

  12. Applications of Microfluidics for Molecular Diagnostics

    OpenAIRE

    Jayamohan, Harikrishnan; Sant, Himanshu J.; Bruce K. Gale

    2012-01-01

    Diagnostic assays implemented in microfluidic devices have developed rapidly over the past decade and are expected to become commonplace in the next few years. Hundreds of microfluidics-based approaches towards clinical diagnostics and pathogen detection have been reported with a general theme of rapid and customizable assays that are potentially cost-effective. This chapter reviews microfluidics in molecular diagnostics based on application areas with a concise review of microfluidics in gen...

  13. Recent Progress of Microfluidics in Translational Applications

    OpenAIRE

    Liu, Zongbin; Han, Xin; Qin, Lidong

    2016-01-01

    Microfluidics, featuring microfabricated structures, is a technology for manipulating fluids at the micrometer scale. The small dimension and flexibility of microfluidic systems are ideal for mimicking molecular and cellular microenvironment, and show great potential in translational research and development. Here, the recent progress of microfluidics in biological and biomedical applications, including molecular analysis, cellular analysis, and chip-based material delivery and biomimetic des...

  14. Transparent polymeric cell culture chip with integrated temperature control and uniform media perfusion

    DEFF Research Database (Denmark)

    Petronis, Sarunas; Stangegaard, Michael; Christensen, C.;

    2006-01-01

    Modern microfabrication and microfluidic technologies offer new opportunities in the design and fabrication of miniaturized cell culture systems for online monitoring of living cells. We used laser micromachining and thermal bonding to fabricate an optically transparent, low-cost polymeric chip for...... long-term online cell culture observation under controlled conditions. The chip incorporated a microfluidic flow equalization system, assuring uniform perfusion of the cell culture media throughout the cell culture chamber. The integrated indium-tin-oxide heater and miniature temperature probe linked...... to an electronic feedback system created steady and spatially uniform thermal conditions with minimal interference to the optical transparency of the chip. The fluidic and thermal performance of the chip was verified by finite element modeling and by operation tests under fluctuating ambient...

  15. Fabrication of a turbid optofluidic phantom device with tunable μa and μ‧s to simulate cutaneous vascular perfusion

    Science.gov (United States)

    Chen, Chen; Ahmed, Midhat; Häfner, Tom; Klämpfl, Florian; Stelzle, Florian; Schmidt, Michael

    2016-07-01

    Microfluidic devices are oftenly used to calibrate the imaging reconstruction, because they simulate the morphology of microvasculature. However, for lack of optical properties in microfluidics, the functional recovery of oximetry information cannot be verified. In this work, we describe the fabrication of a novel turbid optofluidic tissue phantom. It is designed to mimic the vascular perfusion and the turbid nature of cutaneous tissue. This phantom contains an interior hollow microfluidic structure with a diameter of ϕave = 50 μm. The microfluidic structure includes the geometry of an inlet, a river-like assay and an outlet. This structure can be perfused by hemoglobin solution to mimic the cutaneous micro-circulation. The multiple-layered phantom matrices exhibit the representative optical parameters of human skin cutis, namely the absorption coefficient μa and the reduced scattering coefficient . The geometry of the generated microfluidic structure is investigated by using Spectral-Domain Optical Coherence Tomography. This optofluidic phantom bridges the gap between tissue equivalent phantoms and Lab-On-Chip devices. Perspectively, this device can be used to calibrate a variety of optical angiographic imaging approaches.

  16. Synthesis, assembly and device of 1-dimentional nanostructures

    Institute of Scientific and Technical Information of China (English)

    2002-01-01

    Synthesis and assembly of 1-dimentional (1-D) nanostructures and measurement of their electrical and optical properties are very important in fabrication of nanodevices. Recent developments in this field are summarized in this review. The assembling methods can be divided into two classes: assembly using macroscopic field forces and microfluidic-assisted-template-integration. The former can assemble nanowires by controlling direction and intensity of electric or magnetic field, while the latter represents a general assembly strategy for any kind of 1-D nanostructures. The assembly of 1-D nanostructures will make it possible to fabricate nanosensors, nanolasers and nanoscale logic gate circuits for computation.

  17. Field-effect flow control in a polydimethylsiloxane-based microfluidic system.

    Science.gov (United States)

    Buch, J S; Wang, P C; DeVoe, D L; Lee, C S

    2001-10-01

    The application of the field-effect for direct control of electroosmosis in a polydimethylsiloxane (PDMS)-based microfluidic system, constructed on a silicon wafer with a 2.0 microm electrically insulating layer of silicon dioxide, is demonstrated. This microfluidic system consists of a 2.0 cm open microchannel fabricated on a PDMS slab, which can reversibly adhere to the silicon wafer to form a hybrid microfluidic device. Aside from mechanically serving as a robust bottom substrate to seal the channel and support the microfluidic system, the silicon wafer is exploited to achieve field-effect flow control by grounding the semiconductive silicon medium. When an electric field is applied through the channel, a radial electric potential gradient is created across the silicon dioxide layer that allows for direct control of the zeta potential and the resulting electroosmotic flow (EOF). By configuring this microfluidic system with two power supplies at both ends of the microchannel, the applied electric potentials can be varied for manipulating the polarity and the magnitude of the radial electric potential gradient across the silicon dioxide layer. At the same time, the longitudinal potential gradient through the microchannel, which is used to induce EOF, is held constant. The results of EOF control in this hybrid microfluidic system are presented for phosphate buffer at pH 3 and pH 5. It is also demonstrated that EOF control can be performed at higher solution pH of 6 and 7.4 by modifying the silicon wafer surface with cetyltrimethylammonium bromide (CTAB) prior to assembly of the hybrid microfluidic system. Results of EOF control from this study are compared with those reported in the literature involving the use of other microfluidic devices under comparable solution conditions. PMID:11700719

  18. Microfluidic sorting of microtissues.

    Science.gov (United States)

    Buschke, D G; Resto, P; Schumacher, N; Cox, B; Tallavajhula, A; Vivekanandan, A; Eliceiri, K W; Williams, J C; Ogle, B M

    2012-03-01

    Increasingly, invitro culture of adherent cell types utilizes three-dimensional (3D) scaffolds or aggregate culture strategies to mimic tissue-like, microenvironmental conditions. In parallel, new flow cytometry-based technologies are emerging to accurately analyze the composition and function of these microtissues (i.e., large particles) in a non-invasive and high-throughput way. Lacking, however, is an accessible platform that can be used to effectively sort or purify large particles based on analysis parameters. Here we describe a microfluidic-based, electromechanical approach to sort large particles. Specifically, sheath-less asymmetric curving channels were employed to separate and hydrodynamically focus particles to be analyzed and subsequently sorted. This design was developed and characterized based on wall shear stress, tortuosity of the flow path, vorticity of the fluid in the channel, sorting efficiency and enrichment ratio. The large particle sorting device was capable of purifying fluorescently labelled embryoid bodies (EBs) from unlabelled EBs with an efficiency of 87.3% ± 13.5%, and enrichment ratio of 12.2 ± 8.4 (n = 8), while preserving cell viability, differentiation potential, and long-term function. PMID:22505992

  19. Characterization of printable cellular micro-fluidic channels for tissue engineering.

    Science.gov (United States)

    Zhang, Yahui; Yu, Yin; Chen, Howard; Ozbolat, Ibrahim T

    2013-06-01

    Tissue engineering has been a promising field of research, offering hope of bridging the gap between organ shortage and transplantation needs. However, building three-dimensional (3D) vascularized organs remains the main technological barrier to be overcome. One of the major challenges is the inclusion of a vascular network to support cell viability in terms of nutrients and oxygen perfusion. This paper introduces a new approach to the fabrication of vessel-like microfluidic channels that has the potential to be used in thick tissue or organ fabrication in the future. In this research, we investigate the manufacturability of printable micro-fluidic channels, where micro-fluidic channels support mechanical integrity as well as enable fluid transport in 3D. A pressure-assisted solid freeform fabrication platform is developed with a coaxial needle dispenser unit to print hollow hydrogel filaments. The dispensing rheology is studied, and effects of material properties on structural formation of hollow filaments are analyzed. Sample structures are printed through the developed computer-controlled system. In addition, cell viability and gene expression studies are presented in this paper. Cell viability shows that cartilage progenitor cells (CPCs) maintained their viability right after bioprinting and during prolonged in vitro culture. Real-time PCR analysis yielded a relatively higher expression of cartilage-specific genes in alginate hollow filament encapsulating CPCs, compared with monolayer cultured CPCs, which revealed that printable semi-permeable micro-fluidic channels provided an ideal environment for cell growth and function. PMID:23458889

  20. Microfluidic Technologies for Synthetic Biology

    Directory of Open Access Journals (Sweden)

    Sung Kuk Lee

    2011-06-01

    Full Text Available 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.

  1. Magnetic separation in microfluidic systems

    DEFF Research Database (Denmark)

    Smistrup, Kristian

    2007-01-01

    This Ph.D. thesis presents theory, modeling, design, fabrication, experiments and results for microfluidic magnetic separators. A model for magnetic bead movement in a microfluidic channel is presented, and the limits of the model are discussed. The effective magnetic field gradient is defined......, and it is argued that it is a good measure, when comparing the performance of magnetic bead separators. It is described how numeric modelling is used to aid the design of microfluidic magnetic separation systems. An example of a design optimization study is given. A robust fabrication scheme has been developed...... for fabrication of silicon based systems. This fabrication scheme is explained, and it is shown how, it is applied with variations for several designs of magnetic separators. An experimental setup for magnetic separation experiments has been developed. It has been coupled with an image analysis program...

  2. Microfluidic 3D Helix Mixers

    Directory of Open Access Journals (Sweden)

    Georgette B. Salieb-Beugelaar

    2016-10-01

    Full Text Available Polymeric microfluidic systems are well suited for miniaturized devices with complex functionality, and rapid prototyping methods for 3D microfluidic structures are increasingly used. Mixing at the microscale and performing chemical reactions at the microscale are important applications of such systems and we therefore explored feasibility, mixing characteristics and the ability to control a chemical reaction in helical 3D channels produced by the emerging thread template method. Mixing at the microscale is challenging because channel size reduction for improving solute diffusion comes at the price of a reduced Reynolds number that induces a strictly laminar flow regime and abolishes turbulence that would be desired for improved mixing. Microfluidic 3D helix mixers were rapidly prototyped in polydimethylsiloxane (PDMS using low-surface energy polymeric threads, twisted to form 2-channel and 3-channel helices. Structure and flow characteristics were assessed experimentally by microscopy, hydraulic measurements and chromogenic reaction, and were modeled by computational fluid dynamics. We found that helical 3D microfluidic systems produced by thread templating allow rapid prototyping, can be used for mixing and for controlled chemical reaction with two or three reaction partners at the microscale. Compared to the conventional T-shaped microfluidic system used as a control device, enhanced mixing and faster chemical reaction was found to occur due to the combination of diffusive mixing in small channels and flow folding due to the 3D helix shape. Thus, microfluidic 3D helix mixers can be rapidly prototyped using the thread template method and are an attractive and competitive method for fluid mixing and chemical reactions at the microscale.

  3. Hard top soft bottom microfluidic devices for cell culture and chemical analysis.

    Science.gov (United States)

    Mehta, Geeta; Lee, Jay; Cha, Wansik; Tung, Yi-Chung; Linderman, Jennifer J; Takayama, Shuichi

    2009-05-15

    We report fabrication and characterization of microfluidic devices made of thermoplastic and elastomeric polymers. These hard-soft hybrid material devices are motivated by the combined need for large scale manufacturability, enhanced barrier properties to gas permeation and evaporation of aqueous solutions compared to poly(dimethyl siloxane) (PDMS) devices, and compatibility with deformation-based actuation. Channel features are created on rigid polymers such as polyethylene terephthalate glycol (PETG), cyclic olefin copolymer (COC), and polystyrene (PS) by hot embossing. These "hard tops" are bonded to elastomeric "soft bottoms" (polyurethane (PU) or PDMS-parylene C-PDMS) to create devices that can be used for microfluidic cell culture where deformation-based fluid actuation schemes are used to perfuse and recirculate media. The higher barrier properties of this device compared to PDMS devices enable cell culture with less evaporation and creation of hypoxic conditions. PMID:19382754

  4. Microfluidic System for Solution Array Based Bioassays

    Energy Technology Data Exchange (ETDEWEB)

    Dougherty, G M; Tok, J B; Pannu, S S; Rose, K A

    2006-02-10

    The objective of this project is to demonstrate new enabling technology for multiplex biodetection systems that are flexible, miniaturizable, highly automated, low cost, and high performance. It builds on prior successes at LLNL with particle-based solution arrays, such as those used in the Autonomous Pathogen Detection System (APDS) successfully field deployed to multiple locations nationwide. We report the development of a multiplex solution array immunoassay based upon engineered metallic nanorod particles. Nanobarcodes{reg_sign} particles are fabricated by sequential electrodeposition of dissimilar metals within porous alumina templates, yielding optically encoded striping patterns that can be read using standard laboratory microscope optics and PC-based image processing software. The addition of self-assembled monolayer (SAM) coatings and target-specific antibodies allows each encoded class of nanorod particles to be directed against a different antigen target. A prototype assay panel directed against bacterial, viral, and soluble protein targets demonstrates simultaneous detection at sensitivities comparable to state of the art immunoassays, with minimal cross-reactivity. Studies have been performed to characterize the colloidal properties (zeta potential) of the suspended nanorod particles as a function of pH, the ionic strength of the suspending solution, and surface functionalization state. Additional studies have produced means for the non-contact manipulation of the particles, including the insertion of magnetic nickel stripes within the encoding pattern, and control via externally applied electromagnetic fields. Using the results of these studies, the novel Nanobarcodes{reg_sign} based assay was implemented in a prototype automated system with the sample processing functions and optical readout performed on a microfluidic card. The unique physical properties of the nanorod particles enable the development of integrated microfluidic systems for

  5. Microfluidic devices for droplet injection

    Science.gov (United States)

    Aubrecht, Donald; Akartuna, Ilke; Weitz, David

    2012-02-01

    As picoliter-scale reaction vessels, microfluidic water-in-oil emulsions have found application for high-throughput, large-sample number analyses. Often, the biological or chemical system under investigation needs to be encapsulated into droplets to prevent cross contamination prior to the introduction of reaction reagents. Previous techniques of picoinjection or droplet synchronization and merging enable the addition of reagents to individual droplets, but present limitations on what can be added to each droplet. We present microfluidic devices that couple the strengths of picoinjection and droplet merging, allowing us to selectively add precise volume to our droplet reactions.

  6. Osteocyte culture in microfluidic devices

    OpenAIRE

    Wei, Chao; Fan, Beiyuan; Chen, Deyong; Liu, Chao; Wei, Yuanchen; Huo, Bo; You, Lidan; Wang, Junbo; Chen, Jian

    2015-01-01

    This paper presents a microfluidic device (poly-dimethylsiloxane micro channels bonded with glass slides) enabling culture of MLO-Y4 osteocyte like cells. In this study, on-chip collagen coating, cell seeding and culture, as well as staining were demonstrated in a tubing-free manner where gravity was used as the driving force for liquid transportation. MLO-Y4 cells were cultured in microfluidic channels with and without collagen coating where cellular images in a time sequence were taken and ...

  7. Microfluidic Device to Quantify the Behavior of Therapeutic Bacteria in Three-Dimensional Tumor Tissue

    Science.gov (United States)

    Brackett, Emily L.; Swofford, Charles A.; Forbes, Neil S.

    2016-01-01

    Summary Microfluidic devices enable precise quantification of the interactions between anticancer bacteria and tumor tissue. Direct observation of bacterial movement and gene expression in tissue is not possible with either monolayers of cells or tumor-bearing mice. Quantification of these interactions is necessary to understand the inherent mechanisms of bacterial targeting and to develop modified organisms with enhanced therapeutic properties. Here we describe the procedures for designing, printing and assembling microfluidic tumor-on-a-chip devices. We also describe the procedures for inserting three- dimensional tumor-cell masses, exposing to bacteria, and analyzing the resultant images. PMID:26846800

  8. Thiolene-based microfluidic flow cells for surface plasmon resonance imaging.

    Science.gov (United States)

    Sheppard, Gareth; Oseki, Takao; Baba, Akira; Patton, Derek; Kaneko, Futao; Mao, Leidong; Locklin, Jason

    2011-06-01

    Thiolene-based microfluidic devices have been coupled with surface plasmon resonance imaging (SPRI) to provide an integrated platform to study interfacial interactions in both aqueous and organic solutions. In this work, we develop a photolithographic method that interfaces commercially available thiolene resin to gold and glass substrates to generate microfluidic channels with excellent adhesion that leave the underlying sensor surface free from contamination and readily available for surface modification through self-assembly. These devices can sustain high flow rates and have excellent solvent compatibility even with several organic solvents. To demonstrate the versatility of these devices, we have conducted nanomolar detection of streptavidin-biotin interactions using in situ SPRI.

  9. Microfluidic strategy to investigate dynamics of small blood vessel function

    Science.gov (United States)

    Yasotharan, Sanjesh; Bolz, Steffen-Sebastian; Guenther, Axel

    2010-11-01

    Resistance arteries (RAs, 30-300 microns in diameter) that are located within the terminal part of the vascular tree regulate the laminar perfusion of tissue with blood, via the peripheral vascular resistance, and hence controls the systemic blood pressure. The structure of RAs is adapted to actively controlling flow resistance by dynamically changing their diameter, which is non-linearly dependent on the temporal variation of the transmural pressure, perfusion flow rate and spatiotemporal changes in the chemical environment. Increases in systemic blood pressure (hypertension) resulting from pathologic changes in the RA response represent the primary risk factor for cardiovascular diseases. We use a microfluidic strategy to investigate small blood vessels by quantifying structural variations within the arterial wall, RA outer contour and diameter over time. First, we document the artery response to vasomotor drugs that were homogeneously applied at step-wise increasing concentration. Second, we investigate the response in the presence of well-defined axial and circumferential heterogeneities. Artery per- and superfusion is discussed based on microscale PIV measurements of the fluid velocity on both sides of the arterial wall. Structural changes in the arterial wall are quantified using cross-correlation and proper orthogonal decomposition analyses of bright-field micrographs.

  10. Engineering a perfusable 3D human liver platform from iPS cells.

    Science.gov (United States)

    Schepers, Arnout; Li, Cheri; Chhabra, Arnav; Seney, Benjamin Tschudy; Bhatia, Sangeeta

    2016-07-01

    In vitro models of human tissue are crucial to our ability to study human disease as well as develop safe and effective drug therapies. Models of single organs in static and microfluidic culture have been established and shown utility for modeling some aspects of health and disease; however, these systems lack multi-organ interactions that are critical to some aspects of drug metabolism and toxicity. Thus, as part of a consortium of researchers, we have developed a liver chip that meets the following criteria: (1) employs human iPS cells from a patient of interest, (2) cultures cells in perfusable 3D organoids, and (3) is robust to variations in perfusion rate so as to be compatible in series with other specialized tissue chips (e.g. heart, lung). In order to achieve this, we describe methods to form hepatocyte aggregates from primary and iPS-derived cells, alone and in co-culture with support cells. This necessitated a novel culture protocol for the interrupted differentiation of iPS cells that permits their removal from a plated surface and aggregation while maintaining phenotypic hepatic functions. In order to incorporate these 3D aggregates in a perfusable platform, we next encapsulated the cells in a PEG hydrogel to prevent aggregation and overgrowth once on chip. We adapted a C-trap chip architecture from the literature that enabled robust loading with encapsulated organoids and culture over a range of flow rates. Finally, we characterize the liver functions of this iHep organoid chip under perfusion and demonstrate a lifetime of at least 28 days. We envision that such this strategy can be generalized to other microfluidic tissue models and provides an opportunity to query patient-specific liver responses in vitro. PMID:27296616

  11. CT perfusion in acute stroke

    International Nuclear Information System (INIS)

    Stroke is a heterogeneous syndrome caused by multiple mechanisms, all of which result in disruption of normal cerebral blood flow and thereby cause cerebral dysfunction. Its early diagnosis is important as its treatment is dependent on the time elapsed since ictus. Delay in diagnosis and treatment translates into increase neuronal loss and thereby increased morbidity. CT scan, and in particular perfusion CT, has helped greatly in the early diagnosis of stroke. This article is an endeavor to explain the pathophysiology of cerebral ischemia and the role of CT perfusion in detecting it

  12. Dynamic CT myocardial perfusion imaging.

    Science.gov (United States)

    Caruso, Damiano; Eid, Marwen; Schoepf, U Joseph; Jin, Kwang Nam; Varga-Szemes, Akos; Tesche, Christian; Mangold, Stefanie; Spandorfer, Adam; Laghi, Andrea; De Cecco, Carlo N

    2016-10-01

    Non-invasive cardiac imaging has rapidly evolved during the last decade due to advancements in CT based technologies. Coronary CT angiography has been shown to reliably assess coronary anatomy and detect high risk coronary artery disease. However, this technique is limited to anatomical assessment, thus non-invasive techniques for functional assessment of the heart are necessary. CT myocardial perfusion is a new CT based technique that provides functional assessment of the myocardium and allows for a comprehensive assessment of coronary artery disease with a single modality when combined with CTA. This review aims to discuss dynamic CT myocardial perfusion as a new technique in the assessment of CAD.

  13. Noninvasive methods of measuring bone blood perfusion

    OpenAIRE

    Dyke, J. P.; Aaron, R.K.

    2010-01-01

    Measurement of bone blood flow and perfusion characteristics in a noninvasive and serial manner would be advantageous in assessing revascularization after trauma and the possible risk of avascular necrosis. Many disease states, including osteoporosis, osteoarthritis, and bone neoplasms, result in disturbed bone perfusion. A causal link between bone perfusion and remodeling has shown its importance in sustained healing and regrowth following injury. Measurement of perfusion and permeability wi...

  14. A microfluidic mixing system for single-molecule measurements.

    Science.gov (United States)

    Pfeil, Shawn H; Wickersham, Charles E; Hoffmann, Armin; Lipman, Everett A

    2009-05-01

    This article describes the design and fabrication of a microfluidic mixing system optimized for ultrasensitive optical measurements. Channels are replica-molded in polydimethylsiloxane elastomer and sealed with fused-silica coverglass. The resulting devices have broad chemical compatibility and extremely low fluorescence background, enabling measurements of individual molecules under well-characterized nonequilibrium conditions. Fluid delivery and pressure connections are made using an interface that allows for rapid assembly, rapid sample exchange, and modular device replacement while providing access for high numerical aperture optics. PMID:19485532

  15. Quasistatic packings of droplets in flat microfluidic channels

    Science.gov (United States)

    Kadivar, Erfan

    2016-02-01

    As observed in recent experiments, monodisperse droplets self-assemble spontaneously in different ordered packings. In this work, we present a numerical study of the droplet packings in the flat rectangular microfluidic channels. Employing the boundary element method, we numerically solve the Stokes equation in two-dimension and investigate the appearance of droplet packing and transition between one and two-row packings of monodisperse emulsion droplets. By calculating packing force applied on the droplet interface, we investigate the effect of flow rate, droplet size, and surface tension on the packing configurations of droplets and transition between different topological packings.

  16. The culture of human embryonic stem cells in microchannel perfusion bioreactors

    Science.gov (United States)

    Korin, Natanel; Bransky, Avishay; Dinnar, Uri; Levenberg, Shulamit

    2007-12-01

    The culture of human Embryonic Stem (ES) cells in microchannel bioreactors can be highly beneficial for ES cell biology studies and ES tissue engineering applications. In the present study we examine the use of Human Foreskin Fibroblasts (HFF) cells as feeder cells for human ES culture in a microchannel perfusion bioreactor. PDMS microchannels (depth:130 micron) were fabricated using conventional soft-lithography techniques. The channels were sterilized, coated with a human fibronectin solution and seeded with cells. Following a period of static incubation, culture medium was perfused through the channels at various flow rates and cell growth was monitored throughout the culture process. Mass transport and fluid mechanics models were used to evaluate the culture conditions (shear stress, oxygen levels within the micro-bioreactor as a function of the medium flow rate. The conditions for successful long-term culture (>7 days) of HFF under flow were established. Experiments with human embryonic stem cells cultured in microchannels show that the conditions essential to co-culture human ES cell on HFF cells under perfusion differ from the conditions necessary for HFF cell culture. Human ES cells were found to be highly sensitive to flow and culture conditions and did not grow under flow rates which were suitable for HFF long-term culture. Successful culture of undifferentiated human ES cell colonies in a perfusion micro-bioreactor is a basic step towards utilizing microfluidic techniques to explore stem cell biology.

  17. Contact activation of blood coagulation on a defined kaolin/collagen surface in a microfluidic assay

    OpenAIRE

    Zhu, Shu; Diamond, Scott L.

    2014-01-01

    Generation of active Factor XII (FXIIa) triggers blood clotting on artificial surfaces and may also enhance intravascular thrombosis. We developed a patterned kaolin (0 to 0.3 pg/μm2)/type 1 collagen fibril surface for controlled microfluidic clotting assays. Perfusion of whole blood (treated only with a low level of 4 μg/mL of the XIIa inhibitor, corn trypsin inhibitor) drove platelet deposition followed by fibrin formation. At venous wall shear rate (100 s−1), kaolin accelerated onset of fi...

  18. Automatic assessment of cardiac perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur; Stegmann, Mikkel Bille; Larsson, Henrik B.W.

    2004-01-01

    In this paper, a method based on Active Appearance Models (AAM) is applied for automatic registration of myocardial perfusion MRI. A semi-quantitative perfusion assessment of the registered image sequences is presented. This includes the formation of perfusion maps for three parameters; maximum up...

  19. Microfluidic Pneumatic Cages: A Novel Approach for In-chip Crystal Trapping, Manipulation and Controlled Chemical Treatment

    Science.gov (United States)

    Abrishamkar, Afshin; Paradinas, Markos; Bailo, Elena; Rodriguez-Trujillo, Romen; Pfattner, Raphael; Rossi, René M.; Ocal, Carmen; deMello, Andrew J.; Amabilino, David B.; Puigmartí-Luis, Josep

    2016-01-01

    The precise localization and controlled chemical treatment of structures on a surface are significant challenges for common laboratory technologies. Herein, we introduce a microfluidic-based technology, employing a double-layer microfluidic device, which can trap and localize in situ and ex situ synthesized structures on microfluidic channel surfaces. Crucially, we show how such a device can be used to conduct controlled chemical reactions onto on-chip trapped structures and we demonstrate how the synthetic pathway of a crystalline molecular material and its positioning inside a microfluidic channel can be precisely modified with this technology. This approach provides new opportunities for the controlled assembly of structures on surface and for their subsequent treatment. PMID:27500740

  20. Fabrication of plastic microfluidic components

    Science.gov (United States)

    Martin, Peter M.; Matson, Dean W.; Bennett, Wendy D.; Hammerstrom, D. J.

    1998-09-01

    Plastic components have many advantages, including ease of fabrication, low cost, chemical inertness, lightweight, and disposability. We report on the fabrication of three plastics-based microfluidic components: a motherboard, a dialysis unit, and a metal sensor. Microchannels, headers, and interconnects were produced in thin sheets (>=50 microns) of polyimide, PMMA, polyethylene, and polycarbonate using a direct-write excimer laser micromachining system. Machined sheets were laminated by thermal and adhesive bonding to form leak-tight microfluidic components. The microfluidic motherboard borrowed the `functionality on a chip' concept from the electronics industry and was the heart of a complex microfluidic analytical device. The motherboard platform was designed to be tightly integrated and self-contained (i.e., liquid flows are all confined within machined microchannels), reducing the need for tubing with fluid distribution and connectivity. This concept greatly facilitated system integration and miniaturization. As fabricated, the motherboard consisted of three fluid reservoirs connected to micropumps by microchannels. The fluids could either be pumped independently or mixed in microchannels prior to being directed to exterior analytical components via outlet ports. The microdialysis device was intended to separate electrolytic solutes from low volume samples prior to mass spectrometric analysis. The device consisted of a dialysis membrane laminated between opposed serpentine microchannels containing the sample fluid and a buffer solution. The laminated metal sensor consisted of fluid reservoirs, micro-flow channels, micropumps, mixing channels, reaction channels, and detector circuitry.

  1. A microfluidic device with pillars

    DEFF Research Database (Denmark)

    2014-01-01

    The invention provides a microfluidic device for mixing liquid reagents, the device comprises, a chip forming at least one reaction chamber between a bottom and a top and extending between an inlet and an outlet. To enable manufacturing from less rigid materials, the device comprises pillars...

  2. Optical detection in microfluidic systems

    DEFF Research Database (Denmark)

    Mogensen, Klaus Bo; Kutter, Jörg Peter

    2009-01-01

    Optical detection schemes continue to be favoured for measurements in microfluidic systems. A selection of the latest progress mainly within the last two years is critically reviewed. Emphasis is on integrated solutions, such as planar waveguides, coupling schemes to the outside world, evanescent...

  3. Mixing in a Microfluid Device

    DEFF Research Database (Denmark)

    Hjorth, Poul G.; Deryabin, Mikhail

    Mixing of fluids in microchannels cannot rely on turbulence since the flow takes place at extremly low Reynolds numbers. Various active and passive devices have been developed to induce mixing in microfluid flow devices. We describe here a model of an active mixer where a transverse periodic flow...

  4. Topology optimization of microfluidic mixers

    DEFF Research Database (Denmark)

    Andreasen, Casper Schousboe; Gersborg, Allan Roulund; Sigmund, Ole

    2009-01-01

    This paper demonstrates the application of the topology optimization method as a general and systematic approach for microfluidic mixer design. The mixing process is modeled as convection dominated transport in low Reynolds number incompressible flow. The mixer performance is maximized by altering...

  5. Osteocyte culture in microfluidic devices.

    Science.gov (United States)

    Wei, Chao; Fan, Beiyuan; Chen, Deyong; Liu, Chao; Wei, Yuanchen; Huo, Bo; You, Lidan; Wang, Junbo; Chen, Jian

    2015-01-01

    This paper presents a microfluidic device (poly-dimethylsiloxane micro channels bonded with glass slides) enabling culture of MLO-Y4 osteocyte like cells. In this study, on-chip collagen coating, cell seeding and culture, as well as staining were demonstrated in a tubing-free manner where gravity was used as the driving force for liquid transportation. MLO-Y4 cells were cultured in microfluidic channels with and without collagen coating where cellular images in a time sequence were taken and analyzed, confirming the positive effect of collagen coating on phenotype maintaining of MLO-Y4 cells. The proliferating cell nuclear antigen based proliferation assay was used to study cellular proliferation, revealing a higher proliferation rate of MLO-Y4 cells seeded in microfluidic channels without collagen coating compared to the substrates coated with collagen. Furthermore, the effects of channel dimensions (variations in width and height) on the viability of MLO-Y4 cells were explored based on the Calcein-AM and propidium iodide based live/dead assay and the Hoechst 33258 based apoptosis assay, locating the correlation between the decrease in channel width or height and the decrease in cell viability. As a platform technology, this microfluidic device may function as a new cell culture model enabling studies of osteocytes. PMID:25713691

  6. Microfluidic-integrated DNA nanobiosensors.

    Science.gov (United States)

    Ansari, M I Haque; Hassan, Shabir; Qurashi, Ahsanulhaq; Khanday, Firdous Ahmad

    2016-11-15

    Over the last few decades, an increased demand has emerged for integrating biosensors with microfluidic- and nanofluidic-based lab-on-chip (LOC) devices for point-of-care (POC) diagnostics, in the medical industry and environmental monitoring of pathogenic threat agents. Such a merger of microfluidics with biosensing technologies allows for the precise control of volumes, as low as one nanolitre and the integration of various types of bioassays on a single miniaturized platform. This integration offers several favorable advantages, such as low reagent consumption, automation of sample preparation, reduction in processing time, low cost analysis, minimal handling of hazardous materials, high detection accuracy, portability and disposability. This review provides a synopsis of the most recent developments in the microfluidic-integrated biosensing field by delineating the fundamental theory of microfluidics, fabrication techniques and a detailed account of the various transduction methods that are employed. Lastly, the review discusses state-of-the-art DNA biosensors with a focus on optical DNA biosensors.

  7. Microfluidic-integrated DNA nanobiosensors.

    Science.gov (United States)

    Ansari, M I Haque; Hassan, Shabir; Qurashi, Ahsanulhaq; Khanday, Firdous Ahmad

    2016-11-15

    Over the last few decades, an increased demand has emerged for integrating biosensors with microfluidic- and nanofluidic-based lab-on-chip (LOC) devices for point-of-care (POC) diagnostics, in the medical industry and environmental monitoring of pathogenic threat agents. Such a merger of microfluidics with biosensing technologies allows for the precise control of volumes, as low as one nanolitre and the integration of various types of bioassays on a single miniaturized platform. This integration offers several favorable advantages, such as low reagent consumption, automation of sample preparation, reduction in processing time, low cost analysis, minimal handling of hazardous materials, high detection accuracy, portability and disposability. This review provides a synopsis of the most recent developments in the microfluidic-integrated biosensing field by delineating the fundamental theory of microfluidics, fabrication techniques and a detailed account of the various transduction methods that are employed. Lastly, the review discusses state-of-the-art DNA biosensors with a focus on optical DNA biosensors. PMID:27179566

  8. Hyperventilation, cerebral perfusion, and syncope

    DEFF Research Database (Denmark)

    Immink, R V; Pott, F C; Secher, N H;

    2014-01-01

    This review summarizes evidence in humans for an association between hyperventilation (HV)-induced hypocapnia and a reduction in cerebral perfusion leading to syncope defined as transient loss of consciousness (TLOC). The cerebral vasculature is sensitive to changes in both the arterial carbon di...

  9. Artificial tissues in perfusion culture.

    Science.gov (United States)

    Sittinger, M; Schultz, O; Keyszer, G; Minuth, W W; Burmester, G R

    1997-01-01

    In the stagnant environment of traditional culture dishes it is difficult to generate long term experiments or artificial tissues from human cells. For this reason a perfusion culture system with a stable supply of nutrients was developed. Human chondrocytes were seeded three-dimensionally in resorbable polymer fleeces. The cell-polymer tissues were then mounted in newly developed containers (W.W. Minuth et al, Biotechniques, 1996) and continuously perfused by fresh medium for 40 days. Samples from the effluate were analyzed daily, and the pH of the medium and glucose concentration remained stable during this period. The lactid acid concentration increased from 0.17 mg/ml to 0.35 mg/ml, which was influenced by the degradation of the resorbable polymer fibers used as three dimensional support material for the cells. This perfusion system proved to be reliable especially in long term cultures. Any components in the culture medium of the cells could be monitored without disturbances as caused by manual medium replacement. These results suggest the described perfusion culture system to be a valuable and convenient tool for many applications in tissue engineering, especially in the generation of artificial connective tissue.

  10. Xenon ventilation and perfusion studies

    International Nuclear Information System (INIS)

    Xenon ventilation and perfusion techniques were developed to view pulmonary function dynamically. Background from previous studies and from the xenon given the patient can interfere with the visual and computer analysis of the data. A computer program was developed to subtract the various background contributions. The protocol for the studies, the computer program and the results are described. (author)

  11. Placental perfusion - a human alternative

    DEFF Research Database (Denmark)

    Mose, Tina; Knudsen, Lisbeth E

    2006-01-01

    Foetal exposures to environmental and medicinal products have impact on the growth of the foetus (e.g. cigarette smoke) and development of organs (e.g. methylmercury and Thalidomide). Perfusion studies of the human term placenta enable investigation of placental transport of chemical substances...

  12. Methods of reducing non-specific adsorption in microfluidic biosensors

    International Nuclear Information System (INIS)

    Non-specific adsorption (NSA) of biomolecules is a persistent challenge in microfluidic biosensors. Microfluidic biosensors often have immobilized bioreceptors such as antibodies, enzymes, DNAs, etc, via linker molecules such as SAMs (self-assembled monolayers) to enhance immobilization. However, the linker molecules are very susceptible to NSA, causing false responses and decreasing sensitivity. In this paper, we present design methods to reduce the NSA of alkanethiol SAMs, which are popular linker molecules on microfluidic biosensors. Three design parameters were studied for two different chain-length SAMs (n = 2 and 10): (i) SAM incubation time, (ii) surface roughness [0.8 nm and 4.4 nm RMS (root mean square)] and (iii) gold crystal re-growth along (1 1 1) the target orientation. NSA was monitored by surface plasmon resonance (SPR). The results suggest that increased SAM incubation time reduces NSA, and that short-chain SAMs respond more favorably than the long-chain SAMs. Both SAMs were shown to be sensitive to surface roughness, and long-chain SAMs reduced NSA by 75%. Gold crystal re-growth along (1 1 1) the target orientation profoundly reduced NSA on the short-chain SAM. On a gold surface where surface roughness was 0.8 nm and there was strong directional alignment along the (1 1 1) gold crystal, final concentrations of nonspecifically bound proteins were 0.05 ng mm−2 (fibrinogen) and 0.075 ng mm−2 (lysozyme)—significantly lower than other known methods. The results show that optimizing three parameters (SAM incubation time, gold surface roughness and gold crystal orientation) improved SAM sensitivity for fibrinogen–anti-fibrinogen conjugates by a factor of 5 in 2.94 pM, suggesting that the methods are effective for reducing NSA in microfluidic biosensors.

  13. Magnetic resonance perfusion imaging without contrast media

    Energy Technology Data Exchange (ETDEWEB)

    Martirosian, Petros; Graf, Hansjoerg; Schick, Fritz [University Hospital of Tuebingen, Section on Experimental Radiology, Tuebingen (Germany); Boss, Andreas; Schraml, Christina; Schwenzer, Nina F.; Claussen, Claus D. [University Hospital of Tuebingen, Department of Diagnostic and Interventional Radiology, Tuebingen (Germany)

    2010-08-15

    Principles of magnetic resonance imaging techniques providing perfusion-related contrast weighting without administration of contrast media are reported and analysed systematically. Especially common approaches to arterial spin labelling (ASL) perfusion imaging allowing quantitative assessment of specific perfusion rates are described in detail. The potential of ASL for perfusion imaging was tested in several types of tissue. After a systematic comparison of technical aspects of continuous and pulsed ASL techniques the standard kinetic model and tissue properties of influence to quantitative measurements of perfusion are reported. For the applications demonstrated in this paper a flow-sensitive alternating inversion recovery (FAIR) ASL perfusion preparation approach followed by true fast imaging with steady precession (true FISP) data recording was developed and implemented on whole-body scanners operating at 0.2, 1.5 and 3 T for quantitative perfusion measurement in various types of tissue. ASL imaging provides a non-invasive tool for assessment of tissue perfusion rates in vivo. Images recorded from kidney, lung, brain, salivary gland and thyroid gland provide a spatial resolution of a few millimetres and sufficient signal to noise ratio in perfusion maps after 2-5 min of examination time. Newly developed ASL techniques provide especially high image quality and quantitative perfusion maps in tissues with relatively high perfusion rates (as also present in many tumours). Averaging of acquisitions and image subtraction procedures are mandatory, leading to the necessity of synchronization of data recording to breathing in abdominal and thoracic organs. (orig.)

  14. Microfluidic biofunctionalisation protocols to form multi-valent interactions for cell rolling and phenotype modification investigations

    KAUST Repository

    Perozziello, Gerardo

    2013-07-01

    In this study, we propose a fast, simple method to biofunctionalise microfluidic systems for cellomic investigations based on micro-fluidic protocols. Many available processes either require expensive and time-consuming protocols or are incompatible with the fabrication of microfluidic systems. Our method differs from the existing since it is applicable to an assembled system, uses few microlitres of reagents and it is based on the use of microbeads. The microbeads have specific surface moieties to link the biomolecules and couple cell receptors. Furthermore, the microbeads serve as arm spacer and offer the benefit of the multi-valent interaction. Microfluidics was adapted together with topology and biochemistry surface modifications to offer the microenvironment for cellomic studies. Based on this principle, we exploit the streptavidin-biotin interaction to couple antibodies to the biofunctionalised microfluidic environment within 5 h using 200 μL of reagents and biomolecules. We selected the antibodies able to form complexes with the MHC class I (MHC-I) molecules present on the cell membrane and involved in the immune surveillance. To test the microfluidic system, tumour cell lines (RMA) were rolled across the coupled antibodies to recognise and strip MHC-I molecules. As result, we show that cell rolling performed inside a microfluidic chamber functionalised with beads and the opportune antibody facilitate the removal of MHC class I molecules. We showed that the level of median fluorescent intensity of the MHC-I molecules is 300 for cells treated in a not biofunctionalised surface. It decreased to 275 for cells treated in a flat biofunctionalised surface and to 250 for cells treated on a surface where biofunctionalised microbeads were immobilised. The cells with reduced expression of MHC-I molecules showed, after cytotoxicity tests, susceptibility 3.5 times higher than normal cells. © 2013 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  15. Multilayer-based lab-on-a-chip systems for perfused cell-based assays

    Science.gov (United States)

    Klotzbach, Udo; Sonntag, Frank; Grünzner, Stefan; Busek, Mathias; Schmieder, Florian; Franke, Volker

    2014-12-01

    A novel integrated technology chain of laser-microstructured multilayer foils for fast, flexible, and low-cost manufacturing of lab-on-a-chip devices especially for complex cell and tissue culture applications, which provides pulsatile fluid flow within physiological ranges at low media-to-cells ratio, was developed and established. Initially the microfluidic system is constructively divided into individual layers, which are formed by separate foils or plates. Based on the functional boundary conditions and the necessary properties of each layer, their corresponding foils and plates are chosen. In the third step, the foils and plates are laser microstructured and functionalized from both sides. In the fourth and last manufacturing step, the multiple plates and foils are joined using different bonding techniques like adhesive bonding, welding, etc. This multilayer technology together with pneumatically driven micropumps and valves permits the manufacturing of fluidic structures and perfusion systems, which spread out above multiple planes. Based on the established lab-on-a-chip platform for perfused cell-based assays, a multilayer microfluidic system with two parallel connected cell culture chambers was successfully implemented.

  16. Applications of Microfluidics in Stem Cell Biology

    OpenAIRE

    Zhang, Qiucen; Austin, Robert H.

    2012-01-01

    Stem cell research can significantly benefit from recent advances of microfluidics technology. In a rationally designed microfluidics device, analyses of stem cells can be done in a much deeper and wider way than in a conventional tissue culture dish. Miniaturization makes analyses operated in a high-throughput fashion, while controls of fluids help to reconstruct the physiological environments. Through integration with present characterization tools like fluorescent microscope, microfluidics...

  17. Microfluidics for optics and quantitative cell biology

    OpenAIRE

    Campbell, James Kyle

    2008-01-01

    Microfluidics is a quickly expanding field with numerous applications. The advent of rapid-prototyping and soft- lithography allow for easy and inexpensive fabrication of microfluidic devices. Fluid manipulation on the microscale allows for new functionalities of devices and components not available on the macroscale. Fluid flows on the microscale are laminar with chemical mixing defined strictly by diffusion allowing us to design microfluidic devices with precise control of fluid flow and ch...

  18. Corrosion and microfluidics in hot water microsystems

    OpenAIRE

    Eriksson, Mimmi

    2013-01-01

    This thesis addresses some important issues when designing microfluidic systems for hot pressurized water. The properties and behavior of water at elevated temperatures and in micro scale is briefly reviewed, and opportunities and possible problems of using hot pressurized water in microfluidic devices are brought up. Experimental work was focused on corrosion resistance for commonly used microsystem materials in hot pressurized water, and the microfluidic behavior for hot pressurized water. ...

  19. Electrokinetic Properties of Lubricin Antiadhesive Coatings in Microfluidic Systems.

    Science.gov (United States)

    Greene, George W; Duffy, Emer; Shallan, Aliaa; Wuethrich, Alain; Paull, Brett

    2016-02-23

    Lubricin is a glycoprotein found in articular joints which has long been recognized as being an important biological boundary lubricant molecule and, more recently, an impressive antiadhesive that readily self-assembles into a well ordered, polymer brush layer on virtually any substrate. The lubricin molecule possesses an overabundance of anionic charge, a property that is atypical among antiadhesive molecules, that enables its use as a coating for applications involving electrokinetic processes such as electrophoresis and electroosmosis. Coating the surfaces of silica and polymeric microfluidic devices with self-assembled lubricin coatings affords a unique combination of excellent fouling resistance and high charge density that enables notoriously "sticky" biomolecules such as proteins to be used and controlled electrokinetically in the device without complications arising from nonspecific adsorption. Using capillary electrophoresis, we characterized the stability, uniformity, and electrokinetic properties of lubricin coatings applied to silica and PTFE capillaries over a range of run buffer pHs and when exposed to concentrated solutions of protein. In addition, we demonstrate the effectiveness of lubricin as a coating to minimize nonspecific protein adsorption in an electrokinetically controlled polydimethylsiloxane/silica microfluidic device.

  20. Controllable preparation of particles with microfluidics

    Institute of Scientific and Technical Information of China (English)

    Guangsheng Luo; Le Du; Yujun Wang; Yangcheng Lu; Jianhong Xu

    2011-01-01

    This paper reviews recent development and achievements in controllable preparation of nanoparticles,micron spherical and non-spherical particles,using microfluidics.A variety of synthesis strategies are presented and compared,including single-phase and multiphase microflows.The main structures of microfluidic devices and the fundamental principles of microflows for particle preparation are summarized and identified.The controllability of particle size,size distribution,crystal structure,morphology,physical and chemical properties,is examined in terms of the special features of microfluidic reactors.An outlook on opinions and predictions concerning the future development of powder technology with microfluidics is specially provided.

  1. Integrated lenses in polystyrene microfluidic devices

    KAUST Repository

    Fan, Yiqiang

    2013-04-01

    This paper reports a new method for integrating microlenses into microfluidic devices for improved observation. Two demonstration microfluidic devices were provided which were fabricated using this new technique. The integrated microlenses were fabricated using a free-surface thermo-compression molding method on a polystyrene (PS) sheet which was then bonded on top of microfluidic channels as a cover plate, with the convex microlenses providing a magnified image of the channel for the easier observation of the flow in the microchannels. This approach for fabricating the integrated microlens in microfluidic devices is rapid, low cost and without the requirement of cleanroom facilities. © 2013 IEEE.

  2. Myocardial perfusion modeling using MRI

    DEFF Research Database (Denmark)

    Larsson, H B; Fritz-Hansen, T; Rostrup, Egill;

    1996-01-01

    In the present study, it is shown that it is possible to quantify myocardial perfusion using magnetic resonance imaging in combination with gadolinium diethylenetriaminopentaacetic acid (Gd-DTPA). Previously, a simple model and method for measuring myocardial perfusion using an inversion recovery...... of Gd-DTPA (lambda), the vascular blood volume (Vb), and the time delay through the coronary arteries (delta T). The model was evaluated by computer simulation and used on experimental results from seven healthy subjects. The results in the healthy volunteers for a region of interest placed...... in the anterior myocardial wall were (mean +/- SD) Ki = 54 +/- 10 ml/100 g/min, lambda = 30 +/- 3 ml/100 g, Vb = 9 +/- 2 ml/100 g, delta T = 3.2 +/- 1.1 s. These results are in good agreement with similar results obtained by other methods....

  3. Lipid bilayer vesicle generation using microfluidic jetting.

    Science.gov (United States)

    Coyne, Christopher W; Patel, Karan; Heureaux, Johanna; Stachowiak, Jeanne; Fletcher, Daniel A; Liu, Allen P

    2014-01-01

    Bottom-up synthetic biology presents a novel approach for investigating and reconstituting biochemical systems and, potentially, minimal organisms. This emerging field engages engineers, chemists, biologists, and physicists to design and assemble basic biological components into complex, functioning systems from the bottom up. Such bottom-up systems could lead to the development of artificial cells for fundamental biological inquiries and innovative therapies(1,2). Giant unilamellar vesicles (GUVs) can serve as a model platform for synthetic biology due to their cell-like membrane structure and size. Microfluidic jetting, or microjetting, is a technique that allows for the generation of GUVs with controlled size, membrane composition, transmembrane protein incorporation, and encapsulation(3). The basic principle of this method is the use of multiple, high-frequency fluid pulses generated by a piezo-actuated inkjet device to deform a suspended lipid bilayer into a GUV. The process is akin to blowing soap bubbles from a soap film. By varying the composition of the jetted solution, the composition of the encompassing solution, and/or the components included in the bilayer, researchers can apply this technique to create customized vesicles. This paper describes the procedure to generate simple vesicles from a droplet interface bilayer by microjetting. PMID:24637415

  4. Microfluidic approach of Sickled Cell Anemia

    Science.gov (United States)

    Abkarian, Manouk; Loiseau, Etienne; Massiera, Gladys

    2012-11-01

    Sickle Cell Anemia is a disorder of the microcirculation caused by a genetic point mutation that produces an altered hemoglobin protein called HbS. HbS self-assembles reversibly into long rope like fibers inside the red blood cells. The resulting distorded sickled red blood cells are believed to block the smallest capillaries of the tissues producing anemia. Despite the large amount of work that provided a thorough understanding of HbS polymerization in bulk as well as in intact red blood cells at rest, no consequent cellular scale approaches of the study of polymerization and its link to the capillary obstruction have been proposed in microflow, although the problem of obstruction is in essence a circulatory problem. Here, we use microfluidic channels, designed to mimic physiological conditions (flow velocity, oxygen concentration, hematocrit...) of the microcirculation to carry out a biomimetic study at the cellular scale of sickled cell vaso-occlusion. We show that flow geometry, oxygen concentration, white blood cells and free hemoglobin S are essential in the formation of original cell aggregates which could play a role in the vaso-occlusion events.

  5. Microfluidics in amino acid analysis.

    Science.gov (United States)

    Pumera, Martin

    2007-07-01

    Microfluidic devices have been widely used to derivatize, separate, and detect amino acids employing many different strategies. Virtually zero-dead volume interconnections and fast mass transfer in small volume microchannels enable dramatic increases in on-chip derivatization reaction speed, while only minute amounts of sample and reagent are needed. Due to short channel path, fast subsecond separations can be carried out. With sophisticated miniaturized detectors, the whole analytical process can be integrated on one platform. This article reviews developments of lab-on-chip technology in amino acid analysis, it shows important design features such as sample preconcentration, precolumn and postcolumn amino acid derivatization, and unlabeled and labeled amino acid detection with focus on advanced designs. The review also describes important biomedical and space exploration applications of amino acid analysis on microfluidic devices. PMID:17542043

  6. The microfluidic Kelvin water dropper

    CERN Document Server

    Marin, Alvaro G; García-Sánchez, Pablo; Shui, Lingling; Xie, Yanbo; Fontelos, Marco A; Eijkel, Jan C T; Berg, Albert van den; Lohse, Detlef

    2013-01-01

    The so-called "Kelvin water dropper" is a simple experiment demonstrating the spontaneous appearance of induced free charge in droplets emitted through a tube. As Lord Kelvin explained, water droplets spontaneously acquire a net charge during detachment from a faucet due to the presence of electrical fields in their surrounding created by any metallic object. In his experiment, two streams of droplets are allowed to drip from separated nozzles into separated buckets, which are at the same time interconnected through the dripping needles. In this paper we build a microfluidic water dropper and demonstrate that the droplets get charged and break-up due to electrohydrodynamic instabilities. A comparison with recent simulations shows the dependence of the acquired charge in the droplets on different parameters of the system. The phenomenon opens a door to cheap and accessible transformation of pneumatic pressure into electrical energy and to an enhanced control in microfluidic and biophysical manipulation of caps...

  7. Optofluidic encapsulation and manipulation of silicon microchips using image processing based optofluidic maskless lithography and railed microfluidics.

    Science.gov (United States)

    Chung, Su Eun; Lee, Seung Ah; Kim, Jiyun; Kwon, Sunghoon

    2009-10-01

    We demonstrate optofluidic encapsulation of silicon microchips using image processing based optofluidic maskless lithography and manipulation using railed microfluidics. Optofluidic maskless lithography is a dynamic photopolymerization technique of free-floating microstructures within a fluidic channel using spatial light modulator. Using optofluidic maskless lithography via computer-vision aided image processing, polymer encapsulants are fabricated for chip protection and guiding-fins for efficient chip conveying within a fluidic channel. Encapsulated silicon chips with guiding-fins are assembled using railed microfluidics, which is an efficient guiding and heterogeneous self-assembly system of microcomponents. With our technology, externally fabricated silicon microchips are encapsulated, fluidically guided and self-assembled potentially enabling low cost fluidic manipulation and assembly of integrated circuits.

  8. Next generation PCR microfluidic system

    OpenAIRE

    Morris, Angela; Curtin, Damian; McGuire, David; Witherbee, Bryan; Barrett, Brian; Kinahan, David; Sayers, Michael; Sirr, Noel; Hou, Xiaona; Aguanno, Mauro; King, Damien; McCarthy, Conor; Chawke, Brian; Doolan, David; O'Doherty, Sinead

    2010-01-01

    Stokes Bio, founded in 2005, develops innovative microfluidic technologies. In 2008 in collaboration with Monsanto, an application driven development for a high-throughput instrument in the detection and characterisation of Single Nucleotide Polymorphisms (SNPs) in agricultural crops was initiated. Stokes technology is designed to generate aqueous nanolitre scale droplets of reagents and samples, wrapped in a carrier fluid from standard microtitre plates and to mix them using Stokes ...

  9. Integrating plasmonic diagnostics and microfluidics.

    Science.gov (United States)

    Niu, Lifang; Zhang, Nan; Liu, Hong; Zhou, Xiaodong; Knoll, Wolfgang

    2015-09-01

    Plasmonics is generally divided into two categories: surface plasmon resonance (SPR) of electromagnetic modes propagating along a (noble) metal/dielectric interface and localized SPRs (LSPRs) on nanoscopic metallic structures (particles, rods, shells, holes, etc.). Both optical transducer concepts can be combined with and integrated in microfluidic devices for biomolecular analyte detections, with the benefits of small foot-print for point-of-care detection, low-cost for one-time disposal, and ease of being integrated into an array format. The key technologies in such integration include the plasmonic chip, microfluidic channel fabrication, surface bio-functionalization, and selection of the detection scheme, which are selected according to the specifics of the targeting analytes. This paper demonstrates a few examples of the many versions of how to combine plasmonics and integrated microfluidics, using different plasmonic generation mechanisms for different analyte detections. One example is a DNA sensor array using a gold film as substrate and surface plasmon fluorescence spectroscopy and microscopy as the transduction method. This is then compared to grating-coupled SPR for poly(ethylene glycol) thiol interaction detected by angle interrogation, gold nanohole based LSPR chip for biotin-strepavidin detection by wavelength shift, and gold nanoholes/nanopillars for the detection of prostate specific antigen by quantum dot labels excited by the LSPR. Our experimental results exemplified that the plasmonic integrated microfluidics is a promising tool for understanding the biomolecular interactions and molecular recognition process as well as biosensing, especially for on-site or point-of-care diagnostics. PMID:26392832

  10. Perfusion abnormalities in congenital and neoplastic pulmonary disease: comparison of MR perfusion and multislice CT imaging

    International Nuclear Information System (INIS)

    The aim of this work was to assess magnetic resonance (MR) perfusion patterns of chronic, nonembolic pulmonary diseases of congenital and neoplastic origin and to compare the findings with results obtained with pulmonary, contrast-enhanced multislice computed tomography (CT) imaging to prove that congenital and neoplastic pulmonary conditions require MR imaging over the pulmonary perfusion cycle to successfully and directly detect changes in lung perfusion patterns. Twenty-five patients underwent concurrent CT and MR evaluation of chronic pulmonary diseases of congenital (n=15) or neoplastic (n=10) origin. Analysis of MR perfusion and contrast-enhanced CT datasets was realized by defining pulmonary and vascular regions of interest in corresponding positions. MR perfusion calculated time-to-peak enhancement, maximal enhancement and the area under the perfusion curve. CT datasets provided pulmonary signal-to-noise ratio measurements. Vessel centerlines of bronchial arteries were determined. Underlying perfusion type, such as pulmonary arterial or systemic arterial supply, as well as regions with significant variations in perfusion were determined statistically. Analysis of the pulmonary perfusion pattern detected pulmonary arterial supply in 19 patients; six patients showed systemic arterial supply. In pulmonary arterial perfusion, MR and multislice CT imaging consistently detected the perfusion type and regions with altered perfusion patterns. In bronchial arterial supply, MR perfusion and CT imaging showed significant perfusion differences. Patients with bronchial arterial supply had bronchial arteries ranging from 2.0 to 3.6 mm compared with submillimeter diameters in pulmonary arterial perfusion. Dynamic MR imaging of congenital and neoplastic pulmonary conditions allowed characterization of the pulmonary perfusion type. CT imaging suggested the presence of systemic arterial perfusion by visualizing hypertrophied bronchial arteries. (orig.)

  11. Ex vivo lung graft perfusion.

    Science.gov (United States)

    Briot, Raphaël; Gennai, Stéphane; Maignan, Maxime; Souilamas, Redha; Pison, Christophe

    2016-04-01

    This review proposes an update of the state of the art and the ongoing clinical trials of ex vivo lung perfusion for lung transplantation in patients. Ex vivo lung perfusion techniques (EVLP) can be used to evaluate a lung graft outside of the body. The goal of EVLP is to study the functional status of lung grafts that were first rejected for transplantation because they did not match all criteria for a conventional transplantation. After an EVLP evaluation, some of these lungs may be requalified for a possible transplantation in patients. This article proposes an overview of the developments of EVLP techniques. During EVLP, the perfusion and ventilation of the isolated lung preparation are very progressive in order to avoid oedema due to ischaemia-reperfusion injuries. Lung evaluation is mainly based on gasometric (PaO2/FiO2) and rheological criteria (low pulmonary arterial resistance). Several series of patients transplanted with EVLP evaluated lungs have been recently published with promising results. EVLP preparations also allow a better understanding of the physiopathology and treatments of ischaemia-reperfusion injuries. Organ procurements from "non-heart-beating" donors will probably require a wider application of these ex vivo techniques. The development of semi-automated systems might facilitate the clinical use of EVLP techniques. PMID:26746565

  12. Dosimetry in myocardial perfusion imaging

    International Nuclear Information System (INIS)

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  13. Dosimetry in myocardial perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Toledo, Janine M.; Trindade, Bruno; Ribeiro, Tarcisio P.C. [Universidade Federal de Minas Gerais (DEN/UFMG), Belo Horizonte (Brazil). Dept. de Engenharia Nuclear. Programa de Pos-Graduacao em Ciencias e Tecnicas Nucleares

    2011-07-01

    This paper conducts a dosimetric investigation on the myocardial perfusion image protocol, together with a literature reviewing, motivated by the significant statistic increasing on mortality, morbidity and disability associated with cardiovascular disease, surpassing infectious diseases. Nuclear Cardiology plays a role n the diagnostic functional evaluation of the heart and in the prognostic of patients with suspected or known cardiac ischemia. In the context of unstable myocardial ischemic syndrome, myocardial perfusion scintigraphy is a non-invasive procedure performed by administering a radiopharmaceutical targeted to the heart. As tool for this study are that the images obtained by thoracic angiotomography and abdominal aorta as a anatomic and functional information for model reproduction in SISCODES - System of Codes for Absorbed Dose Calculations based on Stochastic Methods. Data were manipulated in order to create a voxel computational model of the heart to be running in MCNP - Monte Carlo Neutron Particle Code. . It was assumed a homogeneous distribution of Tl-201 in cardiac muscle. Simulations of the transport of particles through the voxel and the interaction with the heart tissue were performed. As a result, the isodose curves in the heart model are displayed as well as the dose versus volume histogram of the heart muscle. We conclude that the present computational tools can generate doses distributed in myocardial perfusion. (author)

  14. Monitoring of TGF-β 1-Induced Human Lung Adenocarcinoma A549 Cells Epithelial-Mesenchymal Transformation Process by Measuring Cell Adhesion Force with a Microfluidic Device.

    Science.gov (United States)

    Li, Yuan; Gao, AnXiu; Yu, Ling

    2016-01-01

    The epithelial-mesenchymal transition (EMT) is a process in which epithelial cells lose their cell polarity and cell-cell adhesion, and gain migratory and invasive properties. It is believed that EMT is associated with initiation and completion of the invasion-metastasis cascade. In this study, an economic approach was developed to fabricate a microfluidic device with less instrumentation requirement for the investigation of EMT by quantifying cell adhesion force. Fluid shear force was precisely controlled by a homemade microfluidic perfusion apparatus and interface. The adhesion capability of the human lung adenocarcinoma cell line A549 on different types of extracellular matrix protein was studied. In addition, effects of transforming growth factor-β (TGF-β) on EMT in A549 cells were investigated by characterizing the adhesion force changes and on-chip fluorescent staining. The results demonstrate that the microfluidic device is a potential tool to characterize the epithelial-mesenchymal transition process by measuring cell adhesion force.

  15. Microfluidic Devices for Blood Fractionation

    Directory of Open Access Journals (Sweden)

    Chwee Teck Lim

    2011-07-01

    Full Text Available Blood, a complex biological fluid, comprises 45% cellular components suspended in protein rich plasma. These different hematologic components perform distinct functions in vivo and thus the ability to efficiently fractionate blood into its individual components has innumerable applications in both clinical diagnosis and biological research. Yet, processing blood is not trivial. In the past decade, a flurry of new microfluidic based technologies has emerged to address this compelling problem. Microfluidics is an attractive solution for this application leveraging its numerous advantages to process clinical blood samples. This paper reviews the various microfluidic approaches realized to successfully fractionate one or more blood components. Techniques to separate plasma from hematologic cellular components as well as isolating blood cells of interest including certain rare cells are discussed. Comparisons based on common separation metrics including efficiency (sensitivity, purity (selectivity, and throughput will be presented. Finally, we will provide insights into the challenges associated with blood-based separation systems towards realizing true point-of-care (POC devices and provide future perspectives.

  16. Mail-order microfluidics: evaluation of stereolithography for the production of microfluidic devices.

    Science.gov (United States)

    Au, Anthony K; Lee, Wonjae; Folch, Albert

    2014-04-01

    The vast majority of microfluidic devices are developed in PDMS by molding ("soft lithography") because PDMS is an inexpensive material, has physicochemical properties that are well suited for biomedical and physical sciences applications, and design cycle lengths are generally adequate for prototype development. However, PDMS molding is tediously slow and thus cannot provide the high- or medium-volume production required for the commercialization of devices. While high-throughput plastic molding techniques (e.g. injection molding) exist, the exorbitant cost of the molds and/or the equipment can be a serious obstacle for device commercialization, especially for small startups. High-volume production is not required to reach niche markets such as clinical trials, biomedical research supplies, customized research equipment, and classroom projects. Crucially, both PDMS and plastic molding are layer-by-layer techniques where each layer is produced as a result of physicochemical processes not specified in the initial photomask(s) and where the final device requires assembly by bonding, all resulting in a cost that is very hard to predict at the start of the project. By contrast, stereolithography (SL) is an automated fabrication technique that allows for the production of quasi-arbitrary 3D shapes in a single polymeric material at medium-volume throughputs (ranging from a single part to hundreds of parts). Importantly, SL devices can be designed between several groups using CAD tools, conveniently ordered by mail, and their cost precisely predicted via a web interface. Here we evaluate the resolution of an SL mail-order service and the main causes of resolution loss; the optical clarity of the devices and how to address the lack of clarity for imaging in the channels; and the future role that SL could play in the commercialization of microfluidic devices.

  17. Ultrasound perfusion signal processing for tumor detection

    Science.gov (United States)

    Kim, MinWoo; Abbey, Craig K.; Insana, Michael F.

    2016-04-01

    Enhanced blood perfusion in a tissue mass is an indication of neo-vascularity and a sign of a potential malignancy. Ultrasonic pulsed-Doppler imaging is a preferred modality for noninvasive monitoring of blood flow. However, the weak blood echoes and disorganized slow flow make it difficult to detect perfusion using standard methods without the expense and risk of contrast enhancement. Our research measures the efficiency of conventional power-Doppler (PD) methods at discriminating flow states by comparing measurement performance to that of an ideal discriminator. ROC analysis applied to the experimental results shows that power Doppler methods are just 30-50 % efficient at perfusion flows less than 1ml/min, suggesting an opportunity to improve perfusion assessment through signal processing. A new perfusion estimator is proposed by extending the statistical discriminator approach. We show that 2-D perfusion color imaging may be enhanced using this approach.

  18. Ventilation-perfusion scintigram in diabetics

    International Nuclear Information System (INIS)

    We carried out ventilation and perfusion scintigraphies and pulmonary function tests in 20 diabetics under 50 years of age. 99mTc-MAA perfusion scintigrams showed evidence of minimal nonuniformity (MNU) in four cases (20%) and nonsegmental defect (NSD) in eight cases (40%). There was a ventilation defect in the single-breath image in one case (5%) and a delayed washout in three cases (15%) upon 133Xe ventilation scintigram. In the NSD group, the mean diffusing capacity value was abnormally low and the mean duration of the diabetes was long compared with other groups. The frequency of perfusion defects was higher than that of ventilation abnormalities; moreover, abnormal findings on ventilation scintigrams were very mild compared with those of perfusion defects. Perfusion defects correlated significantly with a decrease in diffusing capacity. These findings suggest that the disturbance in pulmonary arterial perfusion caused a decrease in diffusing capacity in diabetics. (author)

  19. Open-Source Wax RepRap 3-D Printer for Rapid Prototyping Paper-Based Microfluidics.

    Science.gov (United States)

    Pearce, J M; Anzalone, N C; Heldt, C L

    2016-08-01

    The open-source release of self-replicating rapid prototypers (RepRaps) has created a rich opportunity for low-cost distributed digital fabrication of complex 3-D objects such as scientific equipment. For example, 3-D printable reactionware devices offer the opportunity to combine open hardware microfluidic handling with lab-on-a-chip reactionware to radically reduce costs and increase the number and complexity of microfluidic applications. To further drive down the cost while improving the performance of lab-on-a-chip paper-based microfluidic prototyping, this study reports on the development of a RepRap upgrade capable of converting a Prusa Mendel RepRap into a wax 3-D printer for paper-based microfluidic applications. An open-source hardware approach is used to demonstrate a 3-D printable upgrade for the 3-D printer, which combines a heated syringe pump with the RepRap/Arduino 3-D control. The bill of materials, designs, basic assembly, and use instructions are provided, along with a completely free and open-source software tool chain. The open-source hardware device described here accelerates the potential of the nascent field of electrochemical detection combined with paper-based microfluidics by dropping the marginal cost of prototyping to nearly zero while accelerating the turnover between paper-based microfluidic designs. PMID:26763294

  20. Materials for microfluidic chip fabrication.

    Science.gov (United States)

    Ren, Kangning; Zhou, Jianhua; Wu, Hongkai

    2013-11-19

    Through manipulating fluids using microfabricated channel and chamber structures, microfluidics is a powerful tool to realize high sensitive, high speed, high throughput, and low cost analysis. In addition, the method can establish a well-controlled microenivroment for manipulating fluids and particles. It also has rapid growing implementations in both sophisticated chemical/biological analysis and low-cost point-of-care assays. Some unique phenomena emerge at the micrometer scale. For example, reactions are completed in a shorter amount of time as the travel distances of mass and heat are relatively small; the flows are usually laminar; and the capillary effect becomes dominant owing to large surface-to-volume ratios. In the meantime, the surface properties of the device material are greatly amplified, which can lead to either unique functions or problems that we would not encounter at the macroscale. Also, each material inherently corresponds with specific microfabrication strategies and certain native properties of the device. Therefore, the material for making the device plays a dominating role in microfluidic technologies. In this Account, we address the evolution of materials used for fabricating microfluidic chips, and discuss the application-oriented pros and cons of different materials. This Account generally follows the order of the materials introduced to microfluidics. Glass and silicon, the first generation microfluidic device materials, are perfect for capillary electrophoresis and solvent-involved applications but expensive for microfabriaction. Elastomers enable low-cost rapid prototyping and high density integration of valves on chip, allowing complicated and parallel fluid manipulation and in-channel cell culture. Plastics, as competitive alternatives to elastomers, are also rapid and inexpensive to microfabricate. Their broad variety provides flexible choices for different needs. For example, some thermosets support in-situ fabrication of

  1. Integrating Electronics and Microfluidics on Paper.

    Science.gov (United States)

    Hamedi, Mahiar M; Ainla, Alar; Güder, Firat; Christodouleas, Dionysios C; Fernández-Abedul, M Teresa; Whitesides, George M

    2016-07-01

    Paper microfluidics and printed electronics have developed independently, and are incompatible in many aspects. Monolithic integration of microfluidics and electronics on paper is demonstrated. This integration makes it possible to print 2D and 3D fluidic, electrofluidic, and electrical components on paper, and to fabricate devices using them.

  2. Opportunities for microfluidic technologies in synthetic biology

    OpenAIRE

    Gulati, Shelly; Rouilly, Vincent; Niu, Xize; Chappell, James; Kitney, Richard I.; Edel, Joshua B.; Paul S Freemont; deMello, Andrew J.

    2009-01-01

    We introduce microfluidics technologies as a key foundational technology for synthetic biology experimentation. Recent advances in the field of microfluidics are reviewed and the potential of such a technological platform to support the rapid development of synthetic biology solutions is discussed.

  3. Detection methods for centrifugal microfluidic platforms

    DEFF Research Database (Denmark)

    Burger, Robert; Amato, Letizia; Boisen, Anja

    2016-01-01

    Centrifugal microfluidics has attracted much interest from academia as well as industry, since it potentially offers solutions for affordable, user-friendly and portable biosensing. A wide range of so-called fluidic unit operations, e.g. mixing, metering, liquid routing, and particle separation...... for the centrifugal microfluidics platform and cover optical as well as mechanical and electrical detection principles....

  4. Principles, Techniques, and Applications of Tissue Microfluidics

    Science.gov (United States)

    Wade, Lawrence A.; Kartalov, Emil P.; Shibata, Darryl; Taylor, Clive

    2011-01-01

    The principle of tissue microfluidics and its resultant techniques has been applied to cell analysis. Building microfluidics to suit a particular tissue sample would allow the rapid, reliable, inexpensive, highly parallelized, selective extraction of chosen regions of tissue for purposes of further biochemical analysis. Furthermore, the applicability of the techniques ranges beyond the described pathology application. For example, they would also allow the posing and successful answering of new sets of questions in many areas of fundamental research. The proposed integration of microfluidic techniques and tissue slice samples is called "tissue microfluidics" because it molds the microfluidic architectures in accordance with each particular structure of each specific tissue sample. Thus, microfluidics can be built around the tissues, following the tissue structure, or alternatively, the microfluidics can be adapted to the specific geometry of particular tissues. By contrast, the traditional approach is that microfluidic devices are structured in accordance with engineering considerations, while the biological components in applied devices are forced to comply with these engineering presets.

  5. Modular microfluidic system for biological sample preparation

    Energy Technology Data Exchange (ETDEWEB)

    Rose, Klint A.; Mariella, Jr., Raymond P.; Bailey, Christopher G.; Ness, Kevin Dean

    2015-09-29

    A reconfigurable modular microfluidic system for preparation of a biological sample including a series of reconfigurable modules for automated sample preparation adapted to selectively include a) a microfluidic acoustic focusing filter module, b) a dielectrophoresis bacteria filter module, c) a dielectrophoresis virus filter module, d) an isotachophoresis nucleic acid filter module, e) a lyses module, and f) an isotachophoresis-based nucleic acid filter.

  6. A microfluidic platform for controlled biochemical stimulation of twin neuronal networks.

    Science.gov (United States)

    Biffi, Emilia; Piraino, Francesco; Pedrocchi, Alessandra; Fiore, Gianfranco B; Ferrigno, Giancarlo; Redaelli, Alberto; Menegon, Andrea; Rasponi, Marco

    2012-06-01

    Spatially and temporally resolved delivery of soluble factors is a key feature for pharmacological applications. In this framework, microfluidics coupled to multisite electrophysiology offers great advantages in neuropharmacology and toxicology. In this work, a microfluidic device for biochemical stimulation of neuronal networks was developed. A micro-chamber for cell culturing, previously developed and tested for long term neuronal growth by our group, was provided with a thin wall, which partially divided the cell culture region in two sub-compartments. The device was reversibly coupled to a flat micro electrode array and used to culture primary neurons in the same microenvironment. We demonstrated that the two fluidically connected compartments were able to originate two parallel neuronal networks with similar electrophysiological activity but functionally independent. Furthermore, the device allowed to connect the outlet port to a syringe pump and to transform the static culture chamber in a perfused one. At 14 days invitro, sub-networks were independently stimulated with a test molecule, tetrodotoxin, a neurotoxin known to block action potentials, by means of continuous delivery. Electrical activity recordings proved the ability of the device configuration to selectively stimulate each neuronal network individually. The proposed microfluidic approach represents an innovative methodology to perform biological, pharmacological, and electrophysiological experiments on neuronal networks. Indeed, it allows for controlled delivery of substances to cells, and it overcomes the limitations due to standard drug stimulation techniques. Finally, the twin network configuration reduces biological variability, which has important outcomes on pharmacological and drug screening. PMID:22655017

  7. Microalgal motility measurement microfluidic chip for toxicity assessment of heavy metals

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Guoxia [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Department of Biotechnology, Dalian, Liaoning (China); Dalian University, Dalian, Liaoning (China); Wang, Yunhua [Dalian University, Dalian, Liaoning (China); Qin, Jianhua [Dalian Institute of Chemical Physics, Chinese Academy of Sciences, Department of Biotechnology, Dalian, Liaoning (China)

    2012-12-15

    A polydimethylsiloxane microfluidic chip has been developed for the estimation of toxic heavy metals based on measurement of mobility of marine microalgae. The chip is mainly composed of an upstream concentration gradient generator and a downstream perfusion-based chemotatic module. The processes of toxic liquid dilution and diffusion, microalgal culturing, cell stimulation, and online screening can be integrated in this chip, which makes it an attractive approach to simplify toxicity testing procedures. The microalgal motility was adopted as a microfluidic bioassay signal and was evaluated as the percentage of motile cells, curvilinear velocity, average path velocity, and straight line velocity. Two mobile marine microalgae, Platymonas subcordiformis and Platymonas helgolandica var. tsingtaoensis, were confined in the chemotatic module and stimulated by the eight concentration gradients of Cu and Cd generated by the concentration gradient generator. In all cases, a toxic response was detected (i.e., a dose-related inhibition of motility was observed). Only 1.5 h was needed to predict EC{sub 50} values. Thus, the microfluidic chip developed was proved to be useful as a simple and rapid approach in heavy metal detection and might be expanded as a conventional test method in environmental toxicity assessment. (orig.)

  8. A microfluidic platform for controlled biochemical stimulation of twin neuronal networks.

    Science.gov (United States)

    Biffi, Emilia; Piraino, Francesco; Pedrocchi, Alessandra; Fiore, Gianfranco B; Ferrigno, Giancarlo; Redaelli, Alberto; Menegon, Andrea; Rasponi, Marco

    2012-06-01

    Spatially and temporally resolved delivery of soluble factors is a key feature for pharmacological applications. In this framework, microfluidics coupled to multisite electrophysiology offers great advantages in neuropharmacology and toxicology. In this work, a microfluidic device for biochemical stimulation of neuronal networks was developed. A micro-chamber for cell culturing, previously developed and tested for long term neuronal growth by our group, was provided with a thin wall, which partially divided the cell culture region in two sub-compartments. The device was reversibly coupled to a flat micro electrode array and used to culture primary neurons in the same microenvironment. We demonstrated that the two fluidically connected compartments were able to originate two parallel neuronal networks with similar electrophysiological activity but functionally independent. Furthermore, the device allowed to connect the outlet port to a syringe pump and to transform the static culture chamber in a perfused one. At 14 days invitro, sub-networks were independently stimulated with a test molecule, tetrodotoxin, a neurotoxin known to block action potentials, by means of continuous delivery. Electrical activity recordings proved the ability of the device configuration to selectively stimulate each neuronal network individually. The proposed microfluidic approach represents an innovative methodology to perform biological, pharmacological, and electrophysiological experiments on neuronal networks. Indeed, it allows for controlled delivery of substances to cells, and it overcomes the limitations due to standard drug stimulation techniques. Finally, the twin network configuration reduces biological variability, which has important outcomes on pharmacological and drug screening.

  9. Manipulation of microfluidic droplets by electrorheological fluid

    KAUST Repository

    Zhang, Menying

    2009-09-01

    Microfluidics, especially droplet microfluidics, attracts more and more researchers from diverse fields, because it requires fewer materials and less time, produces less waste and has the potential of highly integrated and computer-controlled reaction processes for chemistry and biology. Electrorheological fluid, especially giant electrorheological fluid (GERF), which is considered as a kind of smart material, has been applied to the microfluidic systems to achieve active and precise control of fluid by electrical signal. In this review article, we will introduce recent results of microfluidic droplet manipulation, GERF and some pertinent achievements by introducing GERF into microfluidic system: digital generation, manipulation of "smart droplets" and droplet manipulation by GERF. Once it is combined with real-time detection, integrated chip with multiple functions can be realized. © 2009 Wiley-VCH Verlag GmbH & Co. KGaA.

  10. Hepatic Differentiation of Human Induced Pluripotent Stem Cells in a Perfused 3D Porous Polymer Scaffold for Liver Tissue Engineering

    DEFF Research Database (Denmark)

    Hemmingsen, Mette; Muhammad, Haseena Bashir; Mohanty, Soumyaranjan;

    differentiation of hIPS-derived definitive endoderm (DE) cells in a 3D porous polymer scaffold built-in a perfusable bioreactor. The use of a microfluidic bioreactor array enables the culture of 16 independent tissues in one experimental run and thereby an optimization study to be performed....... to limitations of primary hepatocytes regarding availability and maintenance of functionality, stem cells and especially human induced pluripotent stem cells (hIPS cells) are an attractive cell source for liver tissue engineering. The aim of this part of NanoBio4Trans is to optimize culture and hepatic...

  11. Kinetic ELISA in Microfluidic Channels

    Directory of Open Access Journals (Sweden)

    Debashis Dutta

    2011-06-01

    Full Text Available In this article, we describe the kinetic ELISA of Blue Tongue and Epizootic Hemorrhagic Disease viral antibodies in microfluidic channels by monitoring the rate of generation of the enzyme reaction product under static conditions. It has been shown that this format of the immunoassay allows very reliable quantitation of the target species using inexpensive glass microchips and a standard epifluorescence microscope system coupled to a CCD camera. For the viral antibodies assayed here, the limit of detection (LOD for the analyte concentration in our microchips was established to be 3–5 times lower than that obtained on commercial microwell plates using a fiftieth of the sample volume and less than a third of the incubation time. Our analyses further show that when compared to the end-point ELISA format, the kinetic mode of this assay yields an improvement in the LOD by over an order of magnitude in microfluidic devices. This benefit is primarily realized as the observed variation in the background fluorescence (signal at the start of the enzyme reaction period was significantly larger than that in the rate of signal generation upon repeating these assays in different microchannels/microchips. Because the kinetic ELISA results depend only on the latter quantity, the noise level in them was substantially lower compared to that in its end-point counterpart in which the absolute fluorescence measurements are of greater significance. While a similar benefit was also recorded through implementation of kinetic ELISAs on the microwell platform, the improvement in LOD registered in that system was not as significant as was observed in the case of microfluidic assays.

  12. Long term perfusion system supporting adipogenesis.

    Science.gov (United States)

    Abbott, Rosalyn D; Raja, Waseem K; Wang, Rebecca Y; Stinson, Jordan A; Glettig, Dean L; Burke, Kelly A; Kaplan, David L

    2015-08-01

    Adipose tissue engineered models are needed to enhance our understanding of disease mechanisms and for soft tissue regenerative strategies. Perfusion systems generate more physiologically relevant and sustainable adipose tissue models, however adipocytes have unique properties that make culturing them in a perfusion environment challenging. In this paper we describe the methods involved in the development of two perfusion culture systems (2D and 3D) to test their applicability for long term in vitro adipogenic cultures. It was hypothesized that a silk protein biomaterial scaffold would provide a 3D framework, in combination with perfusion flow, to generate a more physiologically relevant sustainable adipose tissue engineered model than 2D cell culture. Consistent with other studies evaluating 2D and 3D culture systems for adipogenesis we found that both systems successfully model adipogenesis, however 3D culture systems were more robust, providing the mechanical structure required to contain the large, fragile adipocytes that were lost in 2D perfused culture systems. 3D perfusion also stimulated greater lipogenesis and lipolysis and resulted in decreased secretion of LDH compared to 2D perfusion. Regardless of culture configuration (2D or 3D) greater glycerol was secreted with the increased nutritional supply provided by perfusion of fresh media. These results are promising for adipose tissue engineering applications including long term cultures for studying disease mechanisms and regenerative approaches, where both acute (days to weeks) and chronic (weeks to months) cultivation are critical for useful insight.

  13. Personality factors correlate with regional cerebral perfusion.

    Science.gov (United States)

    O'Gorman, R L; Kumari, V; Williams, S C R; Zelaya, F O; Connor, S E J; Alsop, D C; Gray, J A

    2006-06-01

    There is an increasing body of evidence pointing to a neurobiological basis of personality. The purpose of this study was to investigate the biological bases of the major dimensions of Eysenck's and Cloninger's models of personality using a noninvasive magnetic resonance perfusion imaging technique in 30 young, healthy subjects. An unbiased voxel-based analysis was used to identify regions where the regional perfusion demonstrated significant correlation with any of the personality dimensions. Highly significant positive correlations emerged between extraversion and perfusion in the basal ganglia, thalamus, inferior frontal gyrus and cerebellum and between novelty seeking and perfusion in the cerebellum, cuneus and thalamus. Strong negative correlations emerged between psychoticism and perfusion in the basal ganglia and thalamus and between harm avoidance and perfusion in the cerebellar vermis, cuneus and inferior frontal gyrus. These observations suggest that personality traits are strongly associated with resting cerebral perfusion in a variety of cortical and subcortical regions and provide further evidence for the hypothesized neurobiological basis of personality. These results may also have important implications for functional neuroimaging studies, which typically rely on the modulation of cerebral hemodynamics for detection of task-induced activation since personality effects may influence the intersubject variability for both task-related activity and resting cerebral perfusion. This technique also offers a novel approach for the exploration of the neurobiological correlates of human personality.

  14. Computed Tomography (CT) Perfusion in Abdominal Cancer

    DEFF Research Database (Denmark)

    Hansen, Martin Lundsgaard; Norling, Rikke; Lauridsen, Carsten;

    2013-01-01

    Computed Tomography (CT) Perfusion is an evolving method to visualize perfusion in organs and tissue. With the introduction of multidetector CT scanners, it is now possible to cover up to 16 cm in one rotation, and thereby making it possible to scan entire organs such as the liver with a fixed...

  15. Sumatriptan and cerebral perfusion in healthy volunteers.

    Science.gov (United States)

    Scott, A K; Grimes, S; Ng, K; Critchley, M; Breckenridge, A M; Thomson, C; Pilgrim, A J

    1992-04-01

    1. The effect of sumatriptan on regional cerebral perfusion was studied in healthy volunteers. 2. Intravenous sumatriptan (2 mg) had no detectable effect on regional cerebral perfusion as measured using a SPECT system with 99technetiumm labelled hexemethylpropyleneamineoxime. 3. Sumatriptan had no effect on pulse, blood pressure or ECG indices. 4. All six volunteers experienced minor adverse effects during the intravenous infusion.

  16. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Won Yong; Lee, Ki Hyeong; Yoon, Byung Woo; Lee, Sang Bok; Jeon, Beom S. [Samsung Medical Center, Seoul (Korea, Republic of); Lee, Kyung Han; Lee, Myung Chul [Seoul National University College of Medicine, Seoul (Korea, Republic of)

    1996-03-15

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p<0.05). There was no correlation between the severity of the motor abnormality and any of the regional cerebral perfusion indices (p>0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  17. [Assessing myocardial perfusion with positron emission tomography].

    Science.gov (United States)

    vom Dahl, J

    2001-11-01

    Positron emission tomography (PET) of the heart has gained widespread scientific and clinical acceptance with regard to two indications: 1) The detection of perfusion abnormalities by qualitative and semiquantitative analyses of perfusion images at rest and during physical or pharmacological stress using well-validated perfusion tracers, such as N-13 ammonia, Rb-82 rubidium chloride, or O-15 labeled water. 2) Viability imaging of myocardial regions with reduced contractility by combining perfusion measurements with substrate metabolism as assessed from F-18 deoxyglucose utilization. This overview summarizes the use of PET as a perfusion imaging method. With a sensitivity > 90% in combination with high specificity, PET is today the best-validated available nuclear imaging technique for the diagnosis of coronary artery disease (CAD). The short half-life of the perfusion tracers in combination with highly sophisticated hard- and software enables rapid PET studies with high patient throughput. The high diagnostic accuracy and the methological advantages as compared to conventional scintigraphy allows one to use PET perfusion imaging to detect subtle changes in the perfusion reserve for the detection of CAD in high risk but asymptomatic patients as well as in patients with proven CAD undergoing various treatment forms such as risk factor reduction or coronary revascularization. In patients following orthotopic heart transplantation, evolving transplant vasculopathy can be detected at an early stage. Quantitative PET imaging at rest allows for detection of myocardial viability since cellular survival is based on maintenance of a minimal perfusion and structural changes correlate to the degree of perfusion reduction. Furthermore, quantitative assessment of the myocardial perfusion reserve detects the magnitude and competence of collaterals in regions with occluded epicardial collaterals and, thus, imaging of several coronary distribution territories in one noninvasive

  18. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo;

    2010-01-01

    radiolabeled liquid aerosols are not restricted to the presence of obstructive lung disease. Radiolabeled macroaggregated human albumin is the imaging agent of choice for perfusion scintigraphy. An optimal combination of nuclide activities and acquisition times for ventilation and perfusion, collimators......Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas over......, and imaging matrix yields an adequate V/Q SPECT study in approximately 20 minutes of imaging time. The recommended protocol based on the patient remaining in an unchanged position during the initial ventilation study and the perfusion study allows presentation of matching ventilation and perfusion slices...

  19. A One-Square-Millimeter Compact Hollow Structure for Microfluidic Pumping on an All-Glass Chip

    OpenAIRE

    Xing Yue (Larry) Peng

    2016-01-01

    A micro surface tension pump is a new type of low-cost, built-in, all-glass, microfluidic pump on a glass microchip fabricated by one-step glass etching. However, geometric minimization and optimization for practical use are challenging. Here, we report a one-square-millimeter, built-in, all-glass pump controlled by two-way digital gas pressure. The pump consists simply of two joint chambers and a piston between two gas control channels. It does not require pre-perfusion for initialization, a...

  20. Laser Ablation of Polymer Microfluidic Devices

    Science.gov (United States)

    Killeen, Kevin

    2004-03-01

    Microfluidic technology is ideal for processing precious samples of limited volumes. Some of the most important classes of biological samples are both high in sample complexity and low in concentration. Combining the elements of sample pre-concentration, chemical separation and high sensitivity detection with chemical identification is essential for realizing a functional microfluidic based analysis system. Direct write UV laser ablation has been used to rapidly fabricate microfluidic devices capable of high performance liquid chromatography (HPLC)-MS. These chip-LC/MS devices use bio-compatible, solvent resistant and flexible polymer materials such as polyimide. A novel microfluidic to rotary valve interface enables, leak free, high pressure fluid switching between multiple ports of the microfluidic chip-LC/MS device. Electrospray tips with outer dimension of 50 um and inner of 15 um are formed by ablating the polymer material concentrically around a multilayer laminated channel structure. Biological samples of digested proteins were used to evaluate the performance of these microfluidic devices. Liquid chromatography separation and similar sample pretreatments have been performed using polymeric microfluidic devices with on-chip separation channels. Mass spectrometry was performed using an Agilent Technologies 1100 series ion trap mass spectrometer. Low fmol amounts of protein samples were positively and routinely identified by searching the MS/MS spectral data against protein databases. The sensitivity and separation performance of the chip-LC devices has been found to be comparable to state of the art nano-electrospray systems.

  1. Self-contained microfluidic systems: a review.

    Science.gov (United States)

    Boyd-Moss, Mitchell; Baratchi, Sara; Di Venere, Martina; Khoshmanesh, Khashayar

    2016-08-16

    Microfluidic systems enable rapid diagnosis, screening and monitoring of diseases and health conditions using small amounts of biological samples and reagents. Despite these remarkable features, conventional microfluidic systems rely on bulky expensive external equipment, which hinders their utility as powerful analysis tools outside of research laboratories. 'Self-contained' microfluidic systems, which contain all necessary components to facilitate a complete assay, have been developed to address this limitation. In this review, we provide an in-depth overview of self-contained microfluidic systems. We categorise these systems based on their operating mechanisms into three major groups: passive, hand-powered and active. Several examples are provided to discuss the structure, capabilities and shortcomings of each group. In particular, we discuss the self-contained microfluidic systems enabled by active mechanisms, due to their unique capability for running multi-step and highly controllable diagnostic assays. Integration of self-contained microfluidic systems with the image acquisition and processing capabilities of smartphones, especially those equipped with accessory optical components, enables highly sensitive and quantitative assays, which are discussed. Finally, the future trends and possible solutions to expand the versatility of self-contained, stand-alone microfluidic platforms are outlined. PMID:27425637

  2. Cerebral perfusion SPECT in transient ischemic attack

    Energy Technology Data Exchange (ETDEWEB)

    You, D.-L. E-mail: dlyou@mail.kfcc.org.tw; Shieh, F.-Y.; Tzen, K.-Y.; Tsai, M.-F.; Kao, P.-F

    2000-04-01

    Purpose: The purpose of our study is to evaluate the efficacy of cerebral perfusion single photon emission computerized tomography (SPECT) in patients with transient ischemic attack (TIA). Methods: Thirty-seven patients with TIA were collected for study. All patients had transient focal neurological symptoms or signs with complete recovery within 24 h after onset. The patients underwent cerebral perfusion SPECT between 6 h and 11 days after onset, with 10 cases performed within 24 h (group A), nine cases performed between 1 and 3 days (group B), 11 cases performed between 3 and 5 days (group C), and seven cases performed after more than 5 days (group D). A semi-quantitative method was used for analyzing the SPECT data, and the difference ratios between lesion side and contralateral normal side were calculated on each pair of regions of interest. Results: In total, 78.4% (29/37) of patients had reduced perfusion in the cerebral cortical regions or deep nuclei, and the regions with reduced perfusion corresponded with clinical presentations of the patients. The abnormal rate with reduced perfusion was 90.0% in group A, 77.8% in group B, 72.7% in group C and 71.4% in group D. Cross cerebellar diaschisis (CCD) was present in seven patients, and all of the primary cerebral perfusion defects of these patients were located at the territory of left or right middle cerebral artery. Conclusion: Cerebral perfusion SPECT is a potential tool to detect cerebral perfusion defects and CCD in patients with TIA. Although the perfusion defect may persist more than 5 days after onset, we suggest cerebral perfusion SPECT should be performed as soon as possible.

  3. Reconfigurable Prototyping Microfluidic Platform for DEP Manipulation and Capacitive Sensing.

    Science.gov (United States)

    Miled, Amine; Auclair, Benoit; Srasra, Anis; Sawan, Mohamad

    2015-04-01

    In this paper, we present a new rapid prototyping platform dedicated to dielectrophoretic microfluidic manipulation and capacitive cell sensing. The proposed platform offers a reconfigurable design including 4 independently programmable output channels to be distributed across 64 electrodes. Although its range of frequency covers up to 3.4 MHz, signal amplitude accuracy ( +/-10%) was demonstrated for frequencies up to 1 MHz and channel-to-channel phase shift setting was stable up to 1.5 MHz. A test of maximum resistive load showed a 10% attenuation of a 12 V peak-to-peak signal with a 22 Ω load. The platform has an advanced capacitive sensor to measure capacitance variation between in-channel electrodes with a sampling frequency up to 5 kH z. Experimental data of capacitive sensor showed a sensitivity of 100 fF. The sensor can be extended to 4 parallel measurements with lower frequency. We also present a new assembly technique for reusable microfluidic chip based on anisotropic adhesive conductive film, epoxy and PDMS. The proposed platform provides a wide range of control signals depending on the type of manipulation as sine, rectangular or square wave. The frequency range is extendible up to 3.4 MHz, in addition to a programmable phase shift circuit with a minimum phase step of 3.6(°) for each signal. PMID:25879968

  4. Manipulation and stretching of bacteria and liposomes by Microfluidics

    Science.gov (United States)

    Zussman, Eyal; Salalha, Wael

    2006-03-01

    Microfluidic technology can be useful in lab-on-a-chip applications of biological assays, environmental monitoring, detection of toxic materials, as well as for assembly of nano- and micro-scale objects into more complex systems. In this work we focused on the orientation of rod-shaped bacteria (Bacillus) by employing shear flow and a high rate elongation flow, and stretching of giant liposomes with diameter size of tens of microns, which can be used as a simplified model for cell behavior. This was achieved by flows of dilute rod-like bacteria and liposome suspensions within a micro-channel by means of a capillary-driven motion. Fluidic alignment situations were tested, firstly by Venturi-like flow which produces a sufficiently converging and diverging flow, and secondly by sink-like flow in a converging microchannel. In the first method we found that the converging part of the flow aligns rod-like bacteria, whereas the diverging part disaligns them, while in the second method the rod-like bacteria can perfectly align along the streamlines. In addition we used the same technology to test liposome deformation while they are flowing through a Venturi-like microchannel. The microfluidics devices were fabricated from poly(dimethylsiloxane) (PDMS) by soft lithographic techniques.

  5. Microfluidic Systems for Pathogen Sensing: A Review

    Directory of Open Access Journals (Sweden)

    Peter Ertl

    2009-06-01

    Full Text Available Rapid pathogen sensing remains a pressing issue today since conventional identification methodsare tedious, cost intensive and time consuming, typically requiring from 48 to 72 h. In turn, chip based technologies, such as microarrays and microfluidic biochips, offer real alternatives capable of filling this technological gap. In particular microfluidic biochips make the development of fast, sensitive and portable diagnostic tools possible, thus promising rapid and accurate detection of a variety of pathogens. This paper will provide a broad overview of the novel achievements in the field of pathogen sensing by focusing on methods and devices that compliment microfluidics.

  6. Design, modeling and characterization of microfluidic architectures for high flow rate, small footprint microfluidic systems.

    Science.gov (United States)

    Saias, Laure; Autebert, Julien; Malaquin, Laurent; Viovy, Jean-Louis

    2011-03-01

    We propose a strategy for optimizing distribution of flow in a microfluidic chamber for microreactor, lateral flow assay and immunocapture applications. It is aimed at maximizing flow throughput, while keeping footprint, cell thickness, and shear stress in the distribution channels at a minimum, and offering a uniform flow field along the whole analysis chamber. In order to minimize footprint, the traditional tree-like or "rhombus" design, in which distribution microchannels undergo a series of splittings into two subchannels with equal lengths and widths, was replaced by a design in which subchannel lengths are unequal, and widths are analytically adapted within the Hele-Shaw approximation, in order to keep the flow resistance uniform along all flow paths. The design was validated by hydrodynamic flow simulation using COMSOL finite element software. Simulations show that, if the channel is too narrow, the Hele-Shaw approximation loses accuracy, and the flow velocity in the chamber can fluctuate by up to 20%. We thus used COMSOL simulation to fine-tune the channel parameters, and obtained a fluctuation of flow velocity across the whole chamber below 10%. The design was then implemented into a PDMS device, and flow profiles were measured experimentally using particle tracking. Finally, we show that this system can be applied to cell sorting in self-assembling magnetic arrays, increasing flow throughput by a factor 100 as compared to earlier reported designs. PMID:21240403

  7. Detection of myocardial perfusion defect with 320-row volume CT myocardial perfusion imaging

    International Nuclear Information System (INIS)

    Objective: To evaluate the feasibility of 320-row volume CT myocardial perfusion imaging (CT-MPI) in detecting myocardial perfusion defect. Methods: Fourteen patients with positive single-positron emission computed tomography myocardial perfusion imaging (SPECT-MPI) findings underwent both rest and adenosine stress 320-row volume CT-MPI. Rest and stress CT perfusion images were analyzed by employing dedicated software in 320-row CT workstation. Both SPECT-MPI and CT-MPI were evaluated for fixed and reversible perfusion defects using a 16-segment model (apex was excluded). The sensitivity, specificity of 320-row volume CT-MPI in detecting myocardial perfusion defect were evaluated by taking SPECT-MPI as a reference standard. Results: Both rest and stress 320-row volume CT-MPI were successfully performed in all patients. Thirty nine segments with fixed or reversible perfusion defects in all patients were depicted by SPECT-MPI, while 34 perfusion defects in 12 patients were identified by CT-MPI. The sensitivity, specificity of 320-row volume CT-MPI for detection of perfusion defects were 87.2%(34/39), 91.4% (169/185), respectively. Conclusion: 320-row volume CT-MPI has high sensitivity and specificity for detection of myocardial perfusion defects. (authors)

  8. Microfluidic biolector-microfluidic bioprocess control in microtiter plates.

    Science.gov (United States)

    Funke, Matthias; Buchenauer, Andreas; Schnakenberg, Uwe; Mokwa, Wilfried; Diederichs, Sylvia; Mertens, Alan; Müller, Carsten; Kensy, Frank; Büchs, Jochen

    2010-10-15

    In industrial-scale biotechnological processes, the active control of the pH-value combined with the controlled feeding of substrate solutions (fed-batch) is the standard strategy to cultivate both prokaryotic and eukaryotic cells. On the contrary, for small-scale cultivations, much simpler batch experiments with no process control are performed. This lack of process control often hinders researchers to scale-up and scale-down fermentation experiments, because the microbial metabolism and thereby the growth and production kinetics drastically changes depending on the cultivation strategy applied. While small-scale batches are typically performed highly parallel and in high throughput, large-scale cultivations demand sophisticated equipment for process control which is in most cases costly and difficult to handle. Currently, there is no technical system on the market that realizes simple process control in high throughput. The novel concept of a microfermentation system described in this work combines a fiber-optic online-monitoring device for microtiter plates (MTPs)--the BioLector technology--together with microfluidic control of cultivation processes in volumes below 1 mL. In the microfluidic chip, a micropump is integrated to realize distinct substrate flow rates during fed-batch cultivation in microscale. Hence, a cultivation system with several distinct advantages could be established: (1) high information output on a microscale; (2) many experiments can be performed in parallel and be automated using MTPs; (3) this system is user-friendly and can easily be transferred to a disposable single-use system. This article elucidates this new concept and illustrates applications in fermentations of Escherichia coli under pH-controlled and fed-batch conditions in shaken MTPs. PMID:20517981

  9. Regional Cerebral Perfusion in Progressive Supranuclear Palsy

    International Nuclear Information System (INIS)

    Progressive supranuclear palsy (PSP) is a Parkinson-plus syndrome characterized clinically by supranuclear ophthalmoplegia, pseudobulbar palsy, axial rigidity, bradykinesia, postural instability and dementia. Presence of dementia and lack of cortical histopathology suggest the derangement of cortical function by pathological changes in subcortical structures in PSP, which is supported by the pattern of behavioral changes and measurement of brain metabolism using positron emission tomography. This study was done to examine whether there are specific changes of regional cerebral perfusion in PSP and whether there is a correlation between severity of motor abnormaility and degree of changes in cerebral perfusion. We measured regional cerebral perfusion indices in 5 cortical and 2 subcortical areas in 6 patients with a clinical diagnosis of PSP and 6 healthy age and sex matched controls using Tc-99m-HMPAO SPECT. Compared with age and sex matched controls, only superior frontal regional perfusion index was significantly decreased in PSP (p0.05). We affirm the previous reports that perfusion in superior frontal cortex is decreased in PSP. Based on our results that there was no correlation between severity of motor abnormality and cerebral perfusion in the superior frontal cortex, nonmotoric symptoms including dementia needs to be looked at whether there is a correlation with the perfusion abnormality in superior frontal cortex

  10. Microfluidic Analytical Separator for Proteomics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — SHOT proposes an innovative microfluidic device designed to effect a 2-dimensional resolution of a mixture of proteins based on isoelectric point (pI) and molecular...

  11. Multiplex single particle analysis in microfluidics.

    Science.gov (United States)

    Dannhauser, D; Romeo, G; Causa, F; De Santo, I; Netti, P A

    2014-10-21

    A straightforward way to measure separated micrometric sized particles in microfluidic flow is reported. The light scattering profile (LSP) of each single particle is fully characterized by using a CMOS-camera based small angle light scattering (SALS) apparatus, ranging from 2° up to 30°. To ensure controlled particle passage through the incident laser, a viscoelastic 3D alignment effect by viscoelastic induced particle migration has been implemented in a simple and cost-effective microfluidic device. Different polystyrene particle sizes are measured in microfluidic flows and the obtained scattering signatures are matched with the Lorenz-Mie based scattering theory. The results confirm the possibility of using this apparatus for real multiplex particle analyses in microfluidic particle flows.

  12. Microfluidic Analytical Separator for Proteomics Project

    Data.gov (United States)

    National Aeronautics and Space Administration — The proposed innovation is a microfluidic device designed to effect a 2-dimensional resolution of a mixture of proteins based on isoelectric point (pI) and...

  13. 3D-printed microfluidic devices.

    Science.gov (United States)

    Amin, Reza; Knowlton, Stephanie; Hart, Alexander; Yenilmez, Bekir; Ghaderinezhad, Fariba; Katebifar, Sara; Messina, Michael; Khademhosseini, Ali; Tasoglu, Savas

    2016-06-20

    Microfluidics is a flourishing field, enabling a wide range of biochemical and clinical applications such as cancer screening, micro-physiological system engineering, high-throughput drug testing, and point-of-care diagnostics. However, fabrication of microfluidic devices is often complicated, time consuming, and requires expensive equipment and sophisticated cleanroom facilities. Three-dimensional (3D) printing presents a promising alternative to traditional techniques such as lithography and PDMS-glass bonding, not only by enabling rapid design iterations in the development stage, but also by reducing the costs associated with institutional infrastructure, equipment installation, maintenance, and physical space. With the recent advancements in 3D printing technologies, highly complex microfluidic devices can be fabricated via single-step, rapid, and cost-effective protocols, making microfluidics more accessible to users. In this review, we discuss a broad range of approaches for the application of 3D printing technology to fabrication of micro-scale lab-on-a-chip devices.

  14. Microfluidics for High School Chemistry Students

    OpenAIRE

    Hemling, Melissa; Crooks, John A.; Oliver, Piercen M.; Brenner, Katie; Gilbertson, Jennifer; Lisensky, George C.; Weibel, Douglas B.

    2014-01-01

    We present a laboratory experiment that introduces high school chemistry students to microfluidics while teaching fundamental properties of acid–base chemistry. The procedure enables students to create microfluidic systems using nonspecialized equipment that is available in high school classrooms and reagents that are safe, inexpensive, and commercially available. The experiment is designed to ignite creativity and confidence about experimental design in a high school chemistry class. This ex...

  15. Integrated microfluidic device for droplet manipulation

    OpenAIRE

    Basova, E.

    2013-01-01

    Droplets based microfluidic systems have a big potential for the miniaturization of processes for bioanalysis. In the form of droplets, reagents are used in discrete volume, enabling high-throughput chemical reactions as well as single-cell encapsulation. Microreactors of this type can be manipulated and applied in bio-testing. In this work we present a platform for droplet generation and manipulation by using dielectrophoresis force. This platform is an integrated microfluidic device wit...

  16. INTEGRATED MICROFLUIDIC DEVICE FOR DROPLET MANIPULATION

    OpenAIRE

    Basova Evgenia; Drs Jakub; Zemanek Jiri; Hurak Zdenek; Foret František

    2013-01-01

    Droplets based microfluidic systems have a big potential for the miniaturization of processes for bioanalysis. In the form of droplets, reagents are used in discrete volume, enabling high-throughput chemical reactions as well as single-cell encapsulation. Microreactors of this type can be manipulated and applied in bio-testing. In this work we present a platform for droplet generation and manipulation by using dielectrophoresis force. This platform is an integrated microfluidic device wit...

  17. Cochlear perfusion with a viscous fluid.

    Science.gov (United States)

    Wang, Yi; Olson, Elizabeth S

    2016-07-01

    The flow of viscous fluid in the cochlea induces shear forces, which could provide benefit in clinical practice, for example to guide cochlear implant insertion or produce static pressure to the cochlear partition or wall. From a research standpoint, studying the effects of a viscous fluid in the cochlea provides data for better understanding cochlear fluid mechanics. However, cochlear perfusion with a viscous fluid may damage the cochlea. In this work we studied the physiological and anatomical effects of perfusing the cochlea with a viscous fluid. Gerbil cochleae were perfused at a rate of 2.4 μL/min with artificial perilymph (AP) and sodium hyaluronate (Healon, HA) in four different concentrations (0.0625%, 0.125%, 0.25%, 0.5%). The different HA concentrations were applied either sequentially in the same cochlea or individually in different cochleae. The perfusion fluid entered from the round window and was withdrawn from basal scala vestibuli, in order to perfuse the entire perilymphatic space. Compound action potentials (CAP) were measured after each perfusion. After perfusion with increasing concentrations of HA in the order of increasing viscosity, the CAP thresholds generally increased. The threshold elevation after AP and 0.0625% HA perfusion was small or almost zero, and the 0.125% HA was a borderline case, while the higher concentrations significantly elevated CAP thresholds. Histology of the cochleae perfused with the 0.0625% HA showed an intact Reissner's membrane (RM), while in cochleae perfused with 0.125% and 0.25% HA RM was torn. Thus, the CAP threshold elevation was likely due to the broken RM, likely caused by the shear stress produced by the flow of the viscous fluid. Our results and analysis indicate that the cochlea can sustain, without a significant CAP threshold shift, up to a 1.5 Pa shear stress. Beside these finding, in the 0.125% and 0.25% HA perfusion cases, a temporary CAP threshold shift was observed, perhaps due to the presence and

  18. Ventilation-perfusion imaging in pulmonary papillomatosis

    International Nuclear Information System (INIS)

    Three children with laryngeal papillomas involving the lungs had serial ventilation-perfusion scintigrams to assess results of therapy designed to reduce the bronchial involvement. Different imaging patterns were observed depending on size, number, and location of lesions. In early parenchymal involvement a ventilation-perfusion mismatch was seen. The initial and follow-up studies correlated well with clinical and radiographic findings. This noninvasive procedure is helpful in evaluating ventilatory and perfusion impairment in these patients as well as their response to treatment

  19. Microfluidic Devices in Advanced Caenorhabditis elegans Research

    Directory of Open Access Journals (Sweden)

    Muniesh Muthaiyan Shanmugam

    2016-08-01

    Full Text Available The study of model organisms is very important in view of their potential for application to human therapeutic uses. One such model organism is the nematode worm, Caenorhabditis elegans. As a nematode, C. elegans have ~65% similarity with human disease genes and, therefore, studies on C. elegans can be translated to human, as well as, C. elegans can be used in the study of different types of parasitic worms that infect other living organisms. In the past decade, many efforts have been undertaken to establish interdisciplinary research collaborations between biologists, physicists and engineers in order to develop microfluidic devices to study the biology of C. elegans. Microfluidic devices with the power to manipulate and detect bio-samples, regents or biomolecules in micro-scale environments can well fulfill the requirement to handle worms under proper laboratory conditions, thereby significantly increasing research productivity and knowledge. The recent development of different kinds of microfluidic devices with ultra-high throughput platforms has enabled researchers to carry out worm population studies. Microfluidic devices primarily comprises of chambers, channels and valves, wherein worms can be cultured, immobilized, imaged, etc. Microfluidic devices have been adapted to study various worm behaviors, including that deepen our understanding of neuromuscular connectivity and functions. This review will provide a clear account of the vital involvement of microfluidic devices in worm biology.

  20. Microfluidic Devices in Advanced Caenorhabditis elegans Research.

    Science.gov (United States)

    Muthaiyan Shanmugam, Muniesh; Subhra Santra, Tuhin

    2016-01-01

    The study of model organisms is very important in view of their potential for application to human therapeutic uses. One such model organism is the nematode worm, Caenorhabditis elegans. As a nematode, C. elegans have ~65% similarity with human disease genes and, therefore, studies on C. elegans can be translated to human, as well as, C. elegans can be used in the study of different types of parasitic worms that infect other living organisms. In the past decade, many efforts have been undertaken to establish interdisciplinary research collaborations between biologists, physicists and engineers in order to develop microfluidic devices to study the biology of C. elegans. Microfluidic devices with the power to manipulate and detect bio-samples, regents or biomolecules in micro-scale environments can well fulfill the requirement to handle worms under proper laboratory conditions, thereby significantly increasing research productivity and knowledge. The recent development of different kinds of microfluidic devices with ultra-high throughput platforms has enabled researchers to carry out worm population studies. Microfluidic devices primarily comprises of chambers, channels and valves, wherein worms can be cultured, immobilized, imaged, etc. Microfluidic devices have been adapted to study various worm behaviors, including that deepen our understanding of neuromuscular connectivity and functions. This review will provide a clear account of the vital involvement of microfluidic devices in worm biology. PMID:27490525

  1. Dynamics of Microvalve Operations in Integrated Microfluidics

    Directory of Open Access Journals (Sweden)

    Alan T. H. Lau

    2014-02-01

    Full Text Available Pneumatic microvalves are widely used key components for automating liquid manipulation and flow control in microfluidics for more than one decade. Due to their robust operations and the ease of fabrication, tremendous microfluidic systems have been developed with the multiple microvalves for higher throughput and extended functionalities. Therefore, operation performance of the microvalves in the integrated microfluidic devices is crucial to the related applications, in fields such as micro-flows, cell analyses, drug discovery, and physical/chemical detections. It has been reported that operation performance of the microvalves are highly sensitive to the device configuration and pressurization scheme. This implies the further development of integrated microfluidics with a larger number of the valves may suffer the problems of undetermined microvalve behaviors during operations, which can become an unavoidable hurdle in the device design and optimization processes. Herein, we characterize responses of the individual microvalves for different operation configurations, e.g., membrane thicknesses and driving pressures. We investigate also the effects in microfluidics integrated with the more valves, through experiments, modeling and simulations. We show that dynamics of the microvalves is indeed influenced by the configurations, levels of design complexity and positions in the devices. Overall, taken dynamics of the microvalve responses into considerations, this work provides insights and guidelines for better designs of integrated microfluidics for the future applications requiring higher throughput and improved operation performance.

  2. Surface Sensitive Microfluidic Optomechanical Sensors

    CERN Document Server

    Kim, Kyu Hyun

    2014-01-01

    The microfluidic optomechanical resonator (uFOMR) based on a thin-walled glass capillary supports high Q-factor (>1000) mechanical modes in the presence of liquids. In this Letter, the sensitivity of the uFOMR to the surface change is studied by layer-by-layer removal of SiO2 molecules from the uFOMR inner surface using various concentrations of hydrofluoric acid solutions. A frequency downshift is observed with a sensitivity of 1.2 Hz/(pg/mm2), which translates to a surface density detection limit of 83 pg/mm2. This work opens a door to using the optomechanical mode for detection and characterization of molecules present near the resonator surface.

  3. Bistable diverter valve in microfluidics

    Science.gov (United States)

    Tesař, V.; Bandalusena, H. C. H.

    2011-05-01

    Bistable diverter valves are useful for a large number of no-moving-part flow control applications, and there is a considerable interest in using them also in microfluidics, especially for handling small pressure-driven flows. However, with decreasing Reynolds number, the Coanda effect—on which the flow diverting effect depends—becomes less effective. Authors performed a study, involving flow visualisation, PIV experiments, measurements of the flow rates, and numerical flowfield computations, aimed at clarifying behaviour of a typical fluidic valve at low Reynolds numbers. A typical fluidic valve originally developed for high Re operation was demonstrated to be useful, though with progressively limited efficiency, down to surprisingly low Re values as small as Re = 800. Also observed was a previously not reported discontinuation in the otherwise monotonic decrease in performance at Re between 1,500 and 2,000.

  4. Sampling by Fluidics and Microfluidics

    Directory of Open Access Journals (Sweden)

    V. Tesař

    2002-01-01

    Full Text Available Selecting one from several available fluid samples is a procedure often performed especially in chemical engineering. It is usually done by an array of valves sequentially opened and closed. Not generally known is an advantageous alternative: fluidic sampling units without moving parts. In the absence of complete pipe closure, cross-contamination between samples cannot be ruled out. This is eliminated by arranging for small protective flows that clear the cavities and remove any contaminated fluid. Although this complicates the overall circuit layout, fluidic sampling units with these "guard" flows were successfully built and tested. Recent interest in microchemistry leads to additional problems due very low operating Reynolds numbers. This necessitated the design of microfluidic sampling units based on new operating principles.

  5. Microfluidic Sample Preparation for Immunoassays

    Energy Technology Data Exchange (ETDEWEB)

    Visuri, S; Benett, W; Bettencourt, K; Chang, J; Fisher, K; Hamilton, J; Krulevitch, P; Park, C; Stockton, C; Tarte, L; Wang, A; Wilson, T

    2001-08-09

    Researchers at Lawrence Livermore National Laboratory are developing means to collect and identify fluid-based biological pathogens in the forms of proteins, viruses, and bacteria. to support detection instruments, they are developing a flexible fluidic sample preparation unit. The overall goal of this Microfluidic Module is to input a fluid sample, containing background particulates and potentially target compounds, and deliver a processed sample for detection. They are developing techniques for sample purification, mixing, and filtration that would be useful to many applications including immunologic and nucleic acid assays. Many of these fluidic functions are accomplished with acoustic radiation pressure or dielectrophoresis. They are integrating these technologies into packaged systems with pumps and valves to control fluid flow through the fluidic circuit.

  6. 3D-printing of transparent bio-microfluidic devices in PEG-DA.

    Science.gov (United States)

    Urrios, Arturo; Parra-Cabrera, Cesar; Bhattacharjee, Nirveek; Gonzalez-Suarez, Alan M; Rigat-Brugarolas, Luis G; Nallapatti, Umashree; Samitier, Josep; DeForest, Cole A; Posas, Francesc; Garcia-Cordero, José L; Folch, Albert

    2016-06-21

    The vast majority of microfluidic systems are molded in poly(dimethylsiloxane) (PDMS) by soft lithography due to the favorable properties of PDMS: biocompatible, elastomeric, transparent, gas-permeable, inexpensive, and copyright-free. However, PDMS molding involves tedious manual labor, which makes PDMS devices prone to assembly failures and difficult to disseminate to research and clinical settings. Furthermore, the fabrication procedures limit the 3D complexity of the devices to layered designs. Stereolithography (SL), a form of 3D-printing, has recently attracted attention as a way to customize the fabrication of biomedical devices due to its automated, assembly-free 3D fabrication, rapidly decreasing costs, and fast-improving resolution and throughput. However, existing SL resins are not biocompatible and patterning transparent resins at high resolution remains difficult. Here we report procedures for the preparation and patterning of a transparent resin based on low-MW poly(ethylene glycol) diacrylate (MW 250) (PEG-DA-250). The 3D-printed devices are highly transparent and cells can be cultured on PEG-DA-250 prints for several days. This biocompatible SL resin and printing process solves some of the main drawbacks of 3D-printed microfluidic devices: biocompatibility and transparency. In addition, it should also enable the production of non-microfluidic biomedical devices. PMID:27217203

  7. Ex vivo lung perfusion and reconditioning.

    Science.gov (United States)

    Yeung, Jonathan C; Cypel, Marcelo; Massad, Ehab; Keshavjee, Shaf

    2011-01-01

    Normothermic ex vivo lung perfusion can act as a platform for the evaluation and repair of donor lungs. An acellular hyperosmolar solution is perfused anterograde through the donor lungs at 40% of the estimated cardiac output. Following oxygenation of the perfusate by the lung, it passes through a hollow fiber oxygenator supplied with a hypoxic gas mixture to remove oxygen and to maintain physiological carbon dioxide levels. Flow through a heat exchanger to maintain normothermia and a leukocyte filter to remove demarginated leukocytes completes the circuit. Lung function can be measured by the difference in PO2 between the perfusate postlung and postmembrane and by physiological parameters. Utilization of this method of ex vivo donor lung evaluation should reduce concerns of primary graft dysfunction and increase utilization rates of donor lungs. PMID:24412979

  8. Dynamic contrast enhanced MRI for perfusion quantification

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke

    2002-01-01

    Magnetic resonance imaging, during bolus passage of a paramagnetic contrast agent, is used world-wide to obtain parameters that reflect the pathological state of tissue. Abnormal perfusion occurs in diseases such as stoke and tumour. Consequently, perfusion quantication could have signi cant...... clinical value both in diagnosis and treatment of such pathologies. One approach for perfusion quanti cation involves using the contrast mechanism that a ects the transverse relaxation rates of the magnetization, R2 or R 2 , since this provides the most pronounced effect. However, the linearity between...... the contrastagent concentration, [Ca], and the changes in R2 or R 2 has been questioned. In this thesis, an MRI scanner sequence for detection of the longitudinal relaxation rate, R1 during bolus passage was modied for brain perfusion measurements, since the linearity between the changes in R1 and [Ca] is expected...

  9. Bubble dynamics in perfused tissue undergoing decompression.

    Science.gov (United States)

    Meisel, S; Nir, A; Kerem, D

    1981-02-01

    A mathematical model describing bubble dynamics in a perfused tissue undergoing decompression is presented, taking into account physical expansion and inward diffusion from surrounding supersaturated tissue as growth promoting factors and tissue gas elimination by perfusion, tissue elasticity, surface tension and inherent unsaturation as resolving driving forces. The expected behavior after a step reduction of pressure of a bubble initially existing in the tissue, displaying both growth and resolution has been demonstrated. A strong perfusion-dependence of bubble resolution time at low perfusion rates is apparent. The model can account for various exposure pressures and saturation fractions of any inert gas-tissue combination for which a set of physical and physiological parameters is available.

  10. Rapid fabrication of microfluidic polymer electrolyte membrane fuel cell in PDMS by surface patterning of perfluorinated ion-exchange resin

    Energy Technology Data Exchange (ETDEWEB)

    Song, Yong-Ak; Han, Jongyoon [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Department of Biological Engineering, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States); Batista, Candy [Roxbury Community College, 1234 Columbus Ave., Roxbury Crossing, MA 02120 (United States); Sarpeshkar, Rahul [Department of Electrical Engineering and Computer Science, Massachusetts Institute of Technology, 77 Massachusetts Ave., Cambridge, MA 02139 (United States)

    2008-09-01

    In this paper we demonstrate a simple and rapid fabrication method for a microfluidic polymer electrolyte membrane (PEM) fuel cell using polydimethylsiloxane (PDMS), which has become the de facto standard material in BioMEMS. Instead of integrating a Nafion sheet film between two layers of a PDMS device in a traditional ''sandwich format,'' we pattern a perfluorinated ion-exchange resin such as a Nafion resin on a glass substrate using a reversibly bonded PDMS microchannel to generate an ion-selective membrane between the fuel-cell electrodes. After this patterning step, the assembly of the microfluidic fuel cell is accomplished by simple oxygen plasma bonding between the PDMS chip and the glass substrate. In an example implementation, the planar PEM microfluidic fuel cell generates an open circuit voltage of 600-800 mV and delivers a maximum current output of nearly 4 {mu}A. To enhance the power output of the fuel cell we utilize self-assembled colloidal arrays as a support matrix for the Nafion resin. Such arrays allow us to increase the thickness of the ion-selective membrane to 20 {mu}m and increase the current output by 166%. Our novel fabrication method enables rapid prototyping of microfluidic fuel cells to study various ion-exchange resins for the polymer electrolyte membrane. Our work will facilitate the development of miniature, implantable, on-chip power sources for biomedical applications. (author)

  11. Nonrigid registration of myocardial perfusion MRI

    DEFF Research Database (Denmark)

    Ólafsdóttir, Hildur

    2005-01-01

    This paper describes a fully automatic registration of 10 multi-slice myocardial perfusion magnetic resonance image sequences. The registration of these sequences is crucial for the clinical interpretation, which currently is subjected to manual labour. The approach used in this study is a nonrigid...... registration algorithm based on free-form deformations due to Rueckert et al. Inspection of difference images from the wash-out part of the perfusion sequences indicates that a good registration accuracy is obtained....

  12. Perfusion magnetic resonance imaging of the liver

    Institute of Scientific and Technical Information of China (English)

    Choon; Hua; Thng; Tong; San; Koh; David; J; Collins; Dow; Mu; Koh

    2010-01-01

    Perfusion magnetic resonance imaging (MRI) studies quantify the microcirculatory status of liver parenchyma and liver lesions, and can be used for the detection of liver metastases, assessing the effectiveness of antiangiogenic therapy, evaluating tumor viability after anticancer therapy or ablation, and diagnosis of liver cirrhosis and its severity. In this review, we discuss the basic concepts of perfusion MRI using tracer kinetic modeling, the common kinetic models applied for analyses, the MR scanning t...

  13. Ventilation-perfusion scintigraphy in pneumology

    International Nuclear Information System (INIS)

    Perfusion scintigraphy belongs to the most efficient and important techniques available for routine diagnostics in pneumology. Its main field of indication however is restricted to relatively small sectors of the non-invasive exploration of structural and functional lung conditions and interactions, as for instance the diagnosis of pulmonary artery embolism, assessment of the ventilation/perfusion ratio in case of central location of a tumour, and pre-operative pulmonary functional diagnostics. (orig.)

  14. Ventilation-perfused studies using SPECT

    International Nuclear Information System (INIS)

    A method for the quantitative analysis of ventilation-perfusion SPECT studies is decribed and an effort is made to evaluate its usefullness. The technical details of the emthod are described. In the the transaxial reconstructions of the tomographic studies the contour of the lungs is detected and regional values of lung volume, ventilation, perfusion and ventilation-perfusion ratios are calculated. The method is operator independent. The lung volume calculations from the SPECT studies are validated by comparing them with lung volume measurements using the helium dilution technique. A good correlation (r=0.91) was found between the two volumes. SPECT volume was greater than the volume measured with helium dilution, which was attributed to non-gas-containing structures in the. lungs. The use of ventilation-perfusion ratio SPECT is described to evaluate the effect of ionizing radiation on the lungs in patients treated with mantle field irradiation for Hodgkin's disease. Perfusion changes appear as early as 2 months after the start of irradiation. Ventilation changes appear later and relatively minor. No changes are seen outside the radiation portals. The ventilation-perfusion inequality in pulmonary sarcoidosis is treated. It is suggested that the decrease D LCO in these patients may be partly due to an even distribution of ventilation perfusion ratios. An effort is made to establish the properties of a new tracer used for the assessment of the metabolic function of the pulmonary endothelium. The lung uptake of I-123 IMP mimics the distribution of a perfusion tracer and it is suggested that this tracer may be useful for the early detection of pulmonary vascular damage, even when blood flow is still intact. Some aspects of the use of Kr-81m as a ventilation tracer are discussed as well as the effect of noise on Kr-81m SPECT reconstructions. (author). 146 refs.; 39 figs.; 8 tabs

  15. Improved exercise myocardial perfusion during lidoflazine therapy

    International Nuclear Information System (INIS)

    Lidoflazine is a synthetic drug with calcium-channel blocking effects. In a study of 6 patients with severe classic angina pectoris, single-blind administration of lidoflazine was associated with improved myocardial perfusion during exercise as determined by thallium-201 stress scintigraphy. These studies demonstrate that lidoflazine therapy is associated with relief of angina, an increased physical work capacity, and improved regional myocardial perfusion during exercise

  16. A micro-perfusion bioreactor for on line investigation of ECM remodeling under hydrodynamic and biochemical stimulation.

    Science.gov (United States)

    Garziano, A; Urciuolo, F; Imparato, G; Martorina, F; Corrado, B; Netti, P

    2016-03-01

    Tissue-on-chip (TOC) systems aim at replicating complex biological dynamics in vitro with the potential either to improve the understanding of human biology or to develop more accurate therapeutic strategies. To replicate faithfully the intricate interrelationships between cells and their surrounding microenvironment, the three-dimensional (3D) tissue model must possess a responsive extracellular matrix (ECM). ECM remodeling plays a pivotal role in guiding cells and tissues functions and such aspect is somewhat denied during in vitro studies. For this purpose, we fabricated a micro-perfusion bioreactor capable to sustain the viability of 3D engineered tissue models recapitulating the process of the native ECM deposition and assembly. Engineered human dermis micro-tissue precursors (HD-μTP) were used as building blocks to generate a final tissue. HD-μTP were loaded in the perfusion space of the micro-perfusion bioreactor and, under the superimposition of different fluid dynamic regimes and biochemical stimulation, they synthesized new collagen proteins that were, then, assembled in the perfusion space forming a continuum of cells embedded in their own ECM. The micro-perfusion bioreactor was fabricated to allow the on-line monitoring of the oxygen consumption and the assembly of the newly formed collagen network via real time acquisition of the second harmonic generation (SHG) signal. The possibility to detect the collagen reorganization due to both fluid dynamic and biochemical stimulation, let us to define the optimal perfusion configuration in order to obtain a TOC system based on an endogenous and responsive ECM. PMID:26860053

  17. Miscible Organic Solvents Soak Bonding Method Use in a PMMA Multilayer Microfluidic Device

    Directory of Open Access Journals (Sweden)

    He Zhang

    2014-12-01

    Full Text Available In this paper, we proposed a novel bonding technology to fabricate a microfluidic device based on Poly(methyl methacrylate (PMMA. The method, which used chloroform and ethanol as miscible bonding solvent, can complete complex structures rapid assembly (10 min at 40°C. A bonding strength of 267.5 N/cm2 can be achieved, while the micro channel deformation was less than 7.26%. Then we utilized this method to produce a three layers micro mixer, which included a T-shaped inlet channel and six H-shaped mixing units. Numerical simulation indicated that, the well mixing length of the mixer was only about 6 mm when Re = 10. Finally, fluorescence microscopy was used to verify mixer performance. The method provided the potential for mass production of multilayer rigid polymer microfluidic devices.

  18. Perfusion visualization and analysis for pulmonary embolism

    Science.gov (United States)

    Vaz, Michael S.; Kiraly, Atilla P.; Naidich, David P.; Novak, Carol L.

    2005-04-01

    Given the nature of pulmonary embolism (PE), timely and accurate diagnosis is critical. Contrast enhanced high-resolution CT images allow physicians to accurately identify segmental and sub-segmental emboli. However, it is also important to assess the effect of such emboli on the blood flow in the lungs. Expanding upon previous research, we propose a method for 3D visualization of lung perfusion. The proposed method allows users to examine perfusion throughout the entire lung volume at a single glance, with areas of diminished perfusion highlighted so that they are visible independent of the viewing location. This may be particularly valuable for better accuracy in assessing the extent of hemodynamic alterations resulting from pulmonary emboli. The method also facilitates user interaction and may help identify small peripheral sub-segmental emboli otherwise overlooked. 19 patients referred for possible PE were evaluated by CT following the administration of IV contrast media. An experienced thoracic radiologist assessed the 19 datasets with 17 diagnosed as being positive for PE with multiple emboli. Since anomalies in lung perfusion due to PE can alter the distribution of parenchymal densities, we analyzed features collected from histograms of the computed perfusion maps and demonstrate their potential usefulness as a preliminary test to suggest the presence of PE. These histogram features also offer the possibility of distinguishing distinct patterns associated with chronic PE and may even be useful for further characterization of changes in perfusion or overall density resulting from associated conditions such as pneumonia or diffuse lung disease.

  19. Quality assessment of a placental perfusion protocol

    DEFF Research Database (Denmark)

    Mathiesen, Line; Mose, Tina; Mørck, Thit Juul;

    2010-01-01

    Validation of in vitro test systems using the modular approach with steps addressing reliability and relevance is an important aim when developing in vitro tests in e.g. reproductive toxicology. The ex vivo human placental perfusion system may be used for such validation, here presenting the plac......Validation of in vitro test systems using the modular approach with steps addressing reliability and relevance is an important aim when developing in vitro tests in e.g. reproductive toxicology. The ex vivo human placental perfusion system may be used for such validation, here presenting...... the placental perfusion model in Copenhagen including control substances. The positive control substance antipyrine shows no difference in transport regardless of perfusion media used or of terms of delivery (n=59, p... ml h(-1) from the fetal reservoir) when adding 2 (n=7) and 20mg (n=9) FITC-dextran/100 ml fetal perfusion media. Success rate of the Copenhagen placental perfusions is provided in this study, including considerations and quality control parameters. Three checkpoints suggested to determine success...

  20. Quantitative perfusion imaging in magnetic resonance imaging

    International Nuclear Information System (INIS)

    Magnetic resonance imaging (MRI) is recognized for its superior tissue contrast while being non-invasive and free of ionizing radiation. Due to the development of new scanner hardware and fast imaging techniques during the last decades, access to tissue and organ functions became possible. One of these functional imaging techniques is perfusion imaging with which tissue perfusion and capillary permeability can be determined from dynamic imaging data. Perfusion imaging by MRI can be performed by two approaches, arterial spin labeling (ASL) and dynamic contrast-enhanced (DCE) MRI. While the first method uses magnetically labelled water protons in arterial blood as an endogenous tracer, the latter involves the injection of a contrast agent, usually gadolinium (Gd), as a tracer for calculating hemodynamic parameters. Studies have demonstrated the potential of perfusion MRI for diagnostics and also for therapy monitoring. The utilization and application of perfusion MRI are still restricted to specialized centers, such as university hospitals. A broad application of the technique has not yet been implemented. The MRI perfusion technique is a valuable tool that might come broadly available after implementation of standards on European and international levels. Such efforts are being promoted by the respective professional bodies. (orig.)

  1. Rapid microfluidic thermal cycler for nucleic acid amplification

    Energy Technology Data Exchange (ETDEWEB)

    Beer, Neil Reginald; Vafai, Kambiz

    2015-10-27

    A system for thermal cycling a material to be thermal cycled including a microfluidic heat exchanger; a porous medium in the microfluidic heat exchanger; a microfluidic thermal cycling chamber containing the material to be thermal cycled, the microfluidic thermal cycling chamber operatively connected to the microfluidic heat exchanger; a working fluid at first temperature; a first system for transmitting the working fluid at first temperature to the microfluidic heat exchanger; a working fluid at a second temperature, a second system for transmitting the working fluid at second temperature to the microfluidic heat exchanger; a pump for flowing the working fluid at the first temperature from the first system to the microfluidic heat exchanger and through the porous medium; and flowing the working fluid at the second temperature from the second system to the heat exchanger and through the porous medium.

  2. Sequence assembly

    DEFF Research Database (Denmark)

    Scheibye-Alsing, Karsten; Hoffmann, S.; Frankel, Annett Maria;

    2009-01-01

    and plays an important role in processing the information generated by these methods. Here, we provide a comprehensive overview of the current publicly available sequence assembly programs. We describe the basic principles of computational assembly along with the main concerns, such as repetitive sequences...

  3. Microfluidics: an enabling technology for the life sciences

    OpenAIRE

    Zengerle, R.; Koltay, P.; Ducrée, Jens

    2004-01-01

    During the last year we have investigated existing and future markets, products and technologies for microfluidics in the life sciences. Within this paper we present some of the findings and discuss a major trend identified within this project: the development of microfluidic platforms for flexible design of application specific integrated microfluidic systems. We discuss two platforms in detail which are currently under development in our lab: microfluidics on a rotating CD ("Lab-CD") as wel...

  4. [Pulmonary ventilation/perfusion ratio].

    Science.gov (United States)

    Guenard, H

    1987-01-01

    The ratios of ventilatory (V) and perfusion (Q) flow rates in the lung are to a large extent responsible for the efficiency of gas exchange. In a simplified monocompartmental model of the lung, the arterial partial pressure of a given gas (Pa) is a function of several factors: the solubility of this gas in blood, its venous and inspired partial pressures and the V/Q ratio. In a multicompartemental model, the mean arterial partial pressure of the gas is a function of the individual values of Pa in each compartment as well as the distribution of V/Q ratios in the lung and the relationship between the concentration and the partial pressure of the gas. The heterogeneity of the distribution of V/Q results from those of both V and Q. Two factors are mainly responsible for this heterogeneity: the gravity and the morphometric characteristics of bronchi and vessels. V/Q ratios are partially controlled at least in low V/Q compartments since hypoxia in these compartments leads to pulmonary arteriolar vasoconstriction. However lungs V/Q ratios range from 0.1 to 10 with a mode around 1. Age, muscular exercise, posture, accelerations, anesthesia, O2 breathing, pulmonary pathology are factors which may alter the distribution of V/Q ratios. PMID:3332289

  5. Controlling two-phase flow in microfluidic systems using electrowetting

    NARCIS (Netherlands)

    Gu, Hao

    2011-01-01

    Electrowetting (EW)-based digital microfluidic systems (DMF) and droplet-based two-phase flow microfluidic systems (TPF) with closed channels are the most widely used microfluidic platforms. In general, these two approaches have been considered independently. However, integrating the two technologie

  6. Isolation of cancer cells by "in situ" microfluidic biofunctionalization protocols

    DEFF Research Database (Denmark)

    De Vitis, Stefania; Matarise, Giuseppina; Pardeo, Francesca;

    2014-01-01

    The aim of this work is the development of a microfluidic immunosensor for the immobilization of cancer cells and their separation from healthy cells by using "in situ" microfluidic biofunctionalization protocols. These protocols allow to link antibodies on microfluidic device surfaces and can be...

  7. Twente Optical Perfusion Camera: system overview and performance for video rate laser Doppler perfusion imaging

    NARCIS (Netherlands)

    M. Draijer; E. Hondebrink; T. van Leeuwen; W. Steenbergen

    2009-01-01

    We present the Twente Optical Perfusion Camera (TOPCam), a novel laser Doppler Perfusion Imager based on CMOS technology. The tissue under investigation is illuminated and the resulting dynamic speckle pattern is recorded with a high speed CMOS camera. Based on an overall analysis of the signal-to-n

  8. Regional cortical hyper perfusion on perfusion CT during postical motor deficit: A case report

    Energy Technology Data Exchange (ETDEWEB)

    Baik, Hye Jin [Dept. of Radiology, Haeundae Paik Hospital, Inje University College of Medicine, Busan (Korea, Republic of)

    2013-08-15

    Postictal neurologic deficit is a well-known complication mimicking the manifestation of a stroke. We present a case of a patient with clinical evidence of Todd's paralysis correlating with reversible postictal parenchymal changes on perfusion CT and magnetic resonance (MR) imaging. In this case, perfusion CT and MR imaging were helpful in the differential diagnosis of stroke-mimicking conditions.

  9. Valve Concepts for Microfluidic Cell Handling

    Directory of Open Access Journals (Sweden)

    M. Grabowski

    2010-01-01

    Full Text Available 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. By casting these masters with PDMS (polydimethylsiloxane we get polymeric replicas containing the channel network. After a plasma-enhanced bonding process, the two layers are irreversibly bonded to each other. The bonding is tight for pressures up to 2 bar. The valves are integrated into a microfluidic cell handling system that is designed to manipulate cells in the presence of a liquid reagent (e.g. PEG – polyethylene glycol, for cell fusion. For this purpose a user-defined fluid management system is developed. The first test series with human cell lines show that the microfluidic chip is suitable for accumulating cells within a reaction chamber, where they can be flushed by a liquid medium.

  10. Material Biocompatibility for PCR Microfluidic Chips

    KAUST Repository

    Kodzius, Rimantas

    2010-04-23

    As part of the current miniaturization trend, biological reactions and processes are being adapted to microfluidics devices. PCR is the primary method employed in DNA amplification, its miniaturization is central to efforts to develop portable devices for diagnostics and testing purposes. A problem is the PCR-inhibitory effect due to interaction between PCR reagents and the surrounding environment, which effect is increased in high-surface-are-to-volume ration microfluidics. In this study, we evaluated the biocompatibility of various common materials employed in the fabrication of microfluidic chips, including silicon, several kinds of silicon oxide, glasses, plastics, wax, and adhesives. Two-temperature PCR was performed with these materials to determine their PCR-inhibitory effect. In most of the cases, addition of bovine serum albumin effectively improved the reaction yield. We also studied the individual PCR components from the standpoint of adsorption. Most of the materials did not inhibit the DNA, whereas they did show noticeable interaction with the DNA polymerase. Our test, instead of using microfluidic devices, can be easily conducted in common PCR tubes using a standard bench thermocycler. Our data supports an overview of the means by which the materials most bio-friendly to microfluidics can be selected.

  11. Microfluidic CODES: a scalable multiplexed electronic sensor for orthogonal detection of particles in microfluidic channels.

    Science.gov (United States)

    Liu, Ruxiu; Wang, Ningquan; Kamili, Farhan; Sarioglu, A Fatih

    2016-04-21

    Numerous biophysical and biochemical assays rely on spatial manipulation of particles/cells as they are processed on lab-on-a-chip devices. Analysis of spatially distributed particles on these devices typically requires microscopy negating the cost and size advantages of microfluidic assays. In this paper, we introduce a scalable electronic sensor technology, called microfluidic CODES, that utilizes resistive pulse sensing to orthogonally detect particles in multiple microfluidic channels from a single electrical output. Combining the techniques from telecommunications and microfluidics, we route three coplanar electrodes on a glass substrate to create multiple Coulter counters producing distinct orthogonal digital codes when they detect particles. We specifically design a digital code set using the mathematical principles of Code Division Multiple Access (CDMA) telecommunication networks and can decode signals from different microfluidic channels with >90% accuracy through computation even if these signals overlap. As a proof of principle, we use this technology to detect human ovarian cancer cells in four different microfluidic channels fabricated using soft lithography. Microfluidic CODES offers a simple, all-electronic interface that is well suited to create integrated, low-cost lab-on-a-chip devices for cell- or particle-based assays in resource-limited settings.

  12. Transitioning from multi-phase to single-phase microfluidics for long-term culture and treatment of multicellular spheroids.

    Science.gov (United States)

    McMillan, Kay S; Boyd, Marie; Zagnoni, Michele

    2016-09-21

    When compared to methodologies based on low adhesion or hanging drop plates, droplet microfluidics offers several advantages for the formation and culture of multicellular spheroids, such as the potential for higher throughput screening and the use of reduced cell numbers, whilst providing increased stability for plate handling. However, a drawback of the technology is its characteristic compartmentalisation which limits the nutrients available to cells within an emulsion and poses challenges to the exchange of the encapsulated solution, often resulting in short-term cell culture and/or viability issues. The aim of this study was to develop a multi-purpose microfluidic platform that combines the high-throughput characteristics of multi-phase flows with that of ease of perfusion typical of single-phase microfluidics. We developed a versatile system to upscale the formation and long-term culture of multicellular spheroids for testing anticancer treatments, creating an array of fluidically addressable, compact spheroids that could be cultured in either medium or within a gel scaffold. The work provides proof-of-concept results for using this system to test both chemo- and radio-therapeutic protocols using in vitro 3D cancer models. PMID:27477673

  13. Microfluidics of soft granular gels

    Science.gov (United States)

    Nixon, Ryan; Bhattacharjee, Tapomoy; Sawyer, W. Gregory; Angelini, Thomas E.

    Microfluidic methods for encapsulating cells and particles typically involve drop making with two immiscible fluids. The main materials constraint in this approach is surface tension, creating inherent instability between the two fluids. We can eliminate this instability by using miscible inner and outer phases. This is achieved by using granular micro gels which are chemically miscible but physically do not mix. These microgels are yield stress materials, so they flow as solid plugs far from shear gradients, and fluidize where gradients are generated - near an injection nozzle for example. We have found that tuning the yield stress of the material by varying polymer concentration, device performance can be controlled. The solid like behavior of the gel allows us to produces infinitely stable jets that maintain their integrity and configuration over long distances and times. These properties can be combined and manipulated to produce discrete particulate bunches of an inner phase, flowing inside of an outer phase, well enough even to print a Morse code message suspended within flow chambers about a millimeter in diameter moving at millimeters a second.

  14. Droplet Microfluidics for Virus Discovery

    Science.gov (United States)

    Rotem, Assaf; Cockrell, Shelley; Guo, Mira; Pipas, James; Weitz, David

    2012-02-01

    The ability to detect, isolate, and characterize an infectious agent is important for diagnosing and curing infectious diseases. Detecting new viral diseases is a challenge because the number of virus particles is often low and/or localized to a small subset of cells. Even if a new virus is detected, it is difficult to isolate it from clinical or environmental samples where multiple viruses are present each with very different properties. Isolation is crucial for whole genome sequencing because reconstructing a genome from fragments of many different genomes is practically impossible. We present a Droplet Microfluidics platform that can detect, isolate and sequence single viral genomes from complex samples containing mixtures of many viruses. We use metagenomic information about the sample of mixed viruses to select a short genomic sequence whose genome we are interested in characterizing. We then encapsulate single virions from the same sample in picoliter volume droplets and screen for successful PCR amplification of the sequence of interest. The selected drops are pooled and their contents sequenced to reconstruct the genome of interest. This method provides a general tool for detecting, isolating and sequencing genetic elements in clinical and environmental samples.

  15. The Relation Between Perfusion Pattern of Hepatic Artery Perfusion Scintigraphy and Response to Y-90 Microsphere Therapy

    Directory of Open Access Journals (Sweden)

    Bilge Volkan-Salancı

    2013-12-01

    Full Text Available Objective: Hepatic artery perfusion scintigraphy is a routine procedure for patient evaluation before Y-90 radiomicrosphere therapy and mostly used for prediction of extrahepatic leakage. Moreover, it also displays perfusion pattern of tumours, which is an important parameter on success of the therapy. The aim of this study is to assess the relation between the perfusion pattern on hepatic artery perfusion scintigraphy and radiomicrosphere therapy response. Methods: A total of 99 radiomicrosphere therapy applications were carried out in 80 patients (M/F: 55/25. Results: Heterogeneous and diffuse perfusion patterns were observed in 47 patients and 52 patients, respectively. The patients with diffuse perfusion pattern had better therapy response both on FDG PET/CT (p= 0.04 and CT (p=0.008 when compared to those with heterogenous perfusion pattern. Conclusion: Perfusion pattern observed on hepatic artery perfusion scintigraphy may be a successful predictor of early response to radiomicrosphere therapy

  16. Generation and functional assessment of 3D multicellular spheroids in droplet based microfluidics platform.

    Science.gov (United States)

    Sabhachandani, P; Motwani, V; Cohen, N; Sarkar, S; Torchilin, V; Konry, T

    2016-02-01

    Here we describe a robust, microfluidic technique to generate and analyze 3D tumor spheroids, which resembles tumor microenvironment and can be used as a more effective preclinical drug testing and screening model. Monodisperse cell-laden alginate droplets were generated in polydimethylsiloxane (PDMS) microfluidic devices that combine T-junction droplet generation and external gelation for spheroid formation. The proposed approach has the capability to incorporate multiple cell types. For the purposes of our study, we generated spheroids with breast cancer cell lines (MCF-7 drug sensitive and resistant) and co-culture spheroids of MCF-7 together with a fibroblast cell line (HS-5). The device has the capability to house 1000 spheroids on chip for drug screening and other functional analysis. Cellular viability of spheroids in the array part of the device was maintained for two weeks by continuous perfusion of complete media into the device. The functional performance of our 3D tumor models and a dose dependent response of standard chemotherapeutic drug, doxorubicin (Dox) and standard drug combination Dox and paclitaxel (PCT) was analyzed on our chip-based platform. Altogether, our work provides a simple and novel, in vitro platform to generate, image and analyze uniform, 3D monodisperse alginate hydrogel tumors for various omic studies and therapeutic efficiency screening, an important translational step before in vivo studies. PMID:26686985

  17. Investigating Nonalcoholic Fatty Liver Disease in a Liver-on-a-Chip Microfluidic Device

    Science.gov (United States)

    Simonelli, Maria Chiara; Giannitelli, Sara Maria; Businaro, Luca; Trombetta, Marcella; Rainer, Alberto

    2016-01-01

    Background and Aim Nonalcoholic fatty liver disease (NAFLD) is a chronic liver disease worldwide, ranging from simple steatosis to nonalcoholic steatohepatitis, which may progress to cirrhosis, eventually leading to hepatocellular carcinoma (HCC). HCC ranks as the third highest cause of cancer-related death globally, requiring an early diagnosis of NAFLD as a potential risk factor. However, the molecular mechanisms underlying NAFLD are still under investigation. So far, many in vitro studies on NAFLD have been hampered by the limitations of 2D culture systems, in which cells rapidly lose tissue-specific functions. The present liver-on-a-chip approach aims at filling the gap between conventional in vitro models, often scarcely predictive of in vivo conditions, and animal models, potentially biased by their xenogeneic nature. Methods HepG2 cells were cultured into a microfluidically perfused device under free fatty acid (FFA) supplementation, namely palmitic and oleic acid, for 24h and 48h. The device mimicked the endothelial-parenchymal interface of a liver sinusoid, allowing the diffusion of nutrients and removal of waste products similar to the hepatic microvasculature. Assessment of intracellular lipid accumulation, cell viability/cytotoxicity and oxidative stress due to the FFA overload, was performed by high-content analysis methodologies using fluorescence-based functional probes. Results The chip enables gradual and lower intracellular lipid accumulation, higher hepatic cell viability and minimal oxidative stress in microfluidic dynamic vs. 2D static cultures, thus mimicking the chronic condition of steatosis observed in vivo more closely. Conclusions Overall, the liver-on-a-chip system provides a suitable culture microenvironment, representing a more reliable model compared to 2D cultures for investigating NAFLD pathogenesis. Hence, our system is amongst the first in vitro models of human NAFLD developed within a microfluidic device in a sinusoid

  18. Microfluidic serpentine antennas with designed mechanical tunability.

    Science.gov (United States)

    Huang, YongAn; Wang, Yezhou; Xiao, Lin; Liu, Huimin; Dong, Wentao; Yin, Zhouping

    2014-11-01

    This paper describes the design and characterization of microfluidic serpentine antennas with reversible stretchability and designed mechanical frequency modulation (FM). The microfluidic antennas are designed based on the Poisson's ratio of the elastomer in which the liquid alloy antenna is embedded, to controllably decrease, stabilize or increase its resonance frequency when being stretched. Finite element modelling was used in combination with experimental verification to investigate the effects of substrate dimensions and antenna aspect ratios on the FM sensitivity to uniaxial stretching. It could be designed within the range of -1.2 to 0.6 GHz per 100% stretch. When the aspect ratio of the serpentine antenna is between 1.0 and 1.5, the resonance frequency is stable under stretching, bending, and twisting. The presented microfluidic serpentine antenna design could be utilized in the field of wireless mobile communication for the design of wearable electronics, with a stable resonance frequency under dynamic applied strain up to 50%.

  19. Microfluidic Pumps Containing Teflon [Trademark] AF Diaphragms

    Science.gov (United States)

    Willis, Peter; White, Victor; Grunthaner, Frank; Ikeda, Mike; Mathies, Richard A.

    2009-01-01

    Microfluidic pumps and valves based on pneumatically actuated diaphragms made of Teflon AF polymers are being developed for incorporation into laboratory-on-a-chip devices that must perform well over temperature ranges wider than those of prior diaphragm-based microfluidic pumps and valves. Other potential applications include implanted biomedical microfluidic devices, wherein the biocompatability of Teflon AF polymers would be highly advantageous. These pumps and valves have been demonstrated to function stably after cycling through temperatures from -125 to 120 C. These pumps and valves are intended to be successors to similar prior pumps and valves containing diaphragms made of polydimethylsiloxane (PDMS) [commonly known as silicone rubber]. The PDMS-containing valves ae designed to function stably only within the temperature range from 5 to 80 C. Undesirably, PDMS membranes are somwehat porous and retain water. PDMS is especially unsuitable for use at temperatures below 0 C because the formation of ice crystals increases porosity and introduces microshear.

  20. Droplets and Bubbles in Microfluidic Devices

    Science.gov (United States)

    Anna, Shelley Lynn

    2016-01-01

    Precise, tunable emulsions and foams produced in microfluidic geometries have found wide application in biochemical analysis and materials synthesis and characterization. Superb control of the volume, uniformity, and generation rate of droplets and bubbles arises from unique features of the microscale behavior of fluid interfaces. Fluid interfaces confined within microfluidic channels behave quite differently than their counterparts in unbounded flows. Confinement inhibits capillary instabilities so that breakup occurs by largely quasi-static mechanisms. The three-dimensional flow near confined interfaces in rectangular geometries and feedback effects from resistance changes in the entire microfluidic network play important roles in regulating the interfacial deformation. Timescales for transport of surfactants and particles to interfaces compete with flow timescales at the microscale, providing further opportunity for tuning the interfacial coverage and properties of individual droplets and bubbles.

  1. Design and Testing of Digital Microfluidic Biochips

    CERN Document Server

    Zhao, Yang

    2013-01-01

    This book provides a comprehensive methodology for automated design, test and diagnosis, and use of robust, low-cost, and manufacturable digital microfluidic systems. It focuses on the development of a comprehensive CAD optimization framework for digital microfluidic biochips that unifies different design problems. With the increase in system complexity and integration levels, biochip designers can utilize the design methods described in this book to evaluate different design alternatives, and carry out design-space exploration to obtain the best design point. Describes practical design automation tools that address different design problems (e.g., synthesis, droplet routing, control-pin mapping, testing and diagnosis, and error recovery) in a unified manner; Applies test pattern generation and error-recovery techniques for digital microfluidics-based biochips; Uses real bioassays as evaluation examples, e.g., multiplexed in vitro human physiological fluids diagnostics, PCR, protein crystallization.  

  2. Bridging Flows: Microfluidic End‐User Solutions

    DEFF Research Database (Denmark)

    Sabourin, David

    . A second practical challenge users face stems from the peripheral equipment, e.g. pumps, required to drive microfluidic devices. This equipment is often costly and bulky and results in limitations and restrictions on microfluidic device operation, such as the number of channels or devices which can...... be actuated or microscopic observation. To address the above issues interconnection and pumping solutions were developed. Methods for creating multiple, aligned, parallel and planar interconnections well suited to microscopy are described. Both reusable, non‐integrated, and permanent, integrated...... interconnection solutions are presented. The construction of twelve and eight channel miniaturized, mechanically actuated peristaltic pumps is also described. The small footprint of the pumps allows their placement adjacent to microfluidic devices and on microscope stages. The reusable, non...

  3. Planar microfluidics - liquid handling without walls

    CERN Document Server

    Rathgeber, A; Kutschera, H J; Wixforth, A

    2001-01-01

    The miniaturization and integration of electronic circuitry has not only made the enormous increase in performance of semiconductor devices possible but also spawned a myriad of new products and applications ranging from a cellular phone to a personal computer. Similarly, the miniaturization and integration of chemical and biological processes will revolutionize life sciences. Drug design and diagnostics in the genomic era require reliable and cost effective high throughput technologies which can be integrated and allow for a massive parallelization. Microfluidics is the core technology to realize such miniaturized laboratories with feature sizes on a submillimeter scale. Here, we report on a novel microfluidic technology meeting the basic requirements for a microfluidic processor analogous to those of its electronic counterpart: Cost effective production, modular design, high speed, scalability and programmability.

  4. A perspective on microfluidic biofuel cells.

    Science.gov (United States)

    Lee, Jin Wook; Kjeang, Erik

    2010-01-01

    This review article presents how microfluidic technologies and biological materials are paired to assist in the development of low cost, green energy fuel cell systems. Miniaturized biological fuel cells, employing enzymes or microorganisms as biocatalysts in an environmentally benign configuration, can become an attractive candidate for small-scale power source applications such as biological sensors, implantable medical devices, and portable electronics. State-of-the-art biofuel cell technologies are reviewed with emphasis on microfabrication compatibility and microfluidic fuel cell designs. Integrated microfluidic biofuel cell prototypes are examined with comparisons of their performance achievements and fabrication methods. The technical challenges for further developments and the potential research opportunities for practical cell designs are discussed.

  5. Temperature Sensing in Modular Microfluidic Architectures

    Directory of Open Access Journals (Sweden)

    Krisna C. Bhargava

    2016-01-01

    Full Text Available A discrete microfluidic element with integrated thermal sensor was fabricated and demonstrated as an effective probe for process monitoring and prototyping. Elements were constructed using stereolithography and market-available glass-bodied thermistors within the modular, standardized framework of previous discrete microfluidic elements demonstrated in the literature. Flow rate-dependent response due to sensor self-heating and microchannel heating and cooling was characterized and shown to be linear in typical laboratory conditions. An acid-base neutralization reaction was performed in a continuous flow setting to demonstrate applicability in process management: the ratio of solution flow rates was varied to locate the equivalence point in a titration, closely matching expected results. This element potentially enables complex, three-dimensional microfluidic architectures with real-time temperature feedback and flow rate sensing, without application specificity or restriction to planar channel routing formats.

  6. Perfusion harmonic imaging of the human brain

    Science.gov (United States)

    Metzler, Volker H.; Seidel, Guenter; Wiesmann, Martin; Meyer, Karsten; Aach, Til

    2003-05-01

    The fast visualisation of cerebral microcirculation supports diagnosis of acute cerebrovascular diseases. However, the commonly used CT/MRI-based methods are time consuming and, moreover, costly. Therefore we propose an alternative approach to brain perfusion imaging by means of ultrasonography. In spite of the low signal/noise-ratio of transcranial ultrasound and the high impedance of the skull, flow images of cerebral blood flow can be derived by capturing the kinetics of appropriate contrast agents by harmonic ultrasound image sequences. In this paper we propose three different methods for human brain perfusion imaging, each of which yielding flow images indicating the status of the patient's cerebral microcirculation by visualising local flow parameters. Bolus harmonic imaging (BHI) displays the flow kinetics of bolus injections, while replenishment (RHI) and diminution harmonic imaging (DHI) compute flow characteristics from contrast agent continuous infusions. RHI measures the contrast agents kinetics in the influx phase and DHI displays the diminution kinetics of the contrast agent acquired from the decay phase. In clinical studies, BHI- and RHI-parameter images were found to represent comprehensive and reproducible distributions of physiological cerebral blood flow. For DHI it is shown, that bubble destruction and hence perfusion phenomena principally can be displayed. Generally, perfusion harmonic imaging enables reliable and fast bedside imaging of human brain perfusion. Due to its cost efficiency it complements cerebrovascular diagnostics by established CT/MRI-based methods.

  7. Single-perfusion defect and pulmonary embolism

    International Nuclear Information System (INIS)

    One hundred thirty-three ventilation-perfusion scans with angiographic correlation were retrospectively reviewed in a double-blind study to evaluate the frequency of pulmonary embolism (PE) in single perfusion defects (SPDs) regardless of ventilation or chest radiographic abnormalities. Of 28 SPDs, PE was present in 46% (13 cases). Ten of 13 SPDs were located in the basal segments of the right lower lobe, one in the right middle lobe, and two in the left lower lobe, seven of 13 patients had undergone recent surgery. in contrast, in the non-PE group, seven of 15 SPDs were in the right lung and eight in the left lower lobe, only one of 15 patients had undergone recent surgery. In ten of 13 PE and ten of 15 non-PE cases, the ventilation-perfusion and chest radiographic findings showed matching abnormalities. Two of six cases with ventilation-perfusion mismatch had PE and abnormal radiographs. One of two cases with ventilation-perfusion match and normal radiographs had PE

  8. Standardized perfusion value of the esophageal carcinoma and its correlation with quantitative CT perfusion parameter values

    Energy Technology Data Exchange (ETDEWEB)

    Djuric-Stefanovic, A., E-mail: avstefan@eunet.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Saranovic, Dj., E-mail: crvzve4@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Sobic-Saranovic, D., E-mail: dsobic2@gmail.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia); Masulovic, D., E-mail: draganmasulovic@yahoo.com [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Unit of Digestive Radiology (First University Surgical Clinic), Center of Radiology and MR, Clinical Center of Serbia, Belgrade (Serbia); Artiko, V., E-mail: veraart@beotel.rs [Faculty of Medicine, University of Belgrade, Belgrade (Serbia); Center of Nuclear Medicine, Clinical Center of Serbia, Belgrade (Serbia)

    2015-03-15

    Purpose: Standardized perfusion value (SPV) is a universal indicator of tissue perfusion, normalized to the whole-body perfusion, which was proposed to simplify, unify and allow the interchangeability among the perfusion measurements and comparison between the tumor perfusion and metabolism. The aims of our study were to assess the standardized perfusion value (SPV) of the esophageal carcinoma, and its correlation with quantitative CT perfusion measurements: blood flow (BF), blood volume (BV), mean transit time (MTT) and permeability surface area product (PS) of the same tumor volume samples, which were obtained by deconvolution-based CT perfusion analysis. Methods: Forty CT perfusion studies of the esophageal cancer were analyzed, using the commercial deconvolution-based CT perfusion software (Perfusion 3.0, GE Healthcare). The SPV of the esophageal tumor and neighboring skeletal muscle were correlated with the corresponding mean tumor and muscle quantitative CT perfusion parameter values, using Spearman's rank correlation coefficient (r{sub S}). Results: Median SPV of the esophageal carcinoma (7.1; range: 2.8–13.4) significantly differed from the SPV of the skeletal muscle (median: 1.0; range: 0.4–2.4), (Z = −5.511, p < 0.001). The cut-off value of the SPV of 2.5 enabled discrimination of esophageal cancer from the skeletal muscle with sensitivity and specificity of 100%. SPV of the esophageal carcinoma significantly correlated with corresponding tumor BF (r{sub S} = 0.484, p = 0.002), BV (r{sub S} = 0.637, p < 0.001) and PS (r{sub S} = 0.432, p = 0.005), and SPV of the skeletal muscle significantly correlated with corresponding muscle BF (r{sub S} = 0.573, p < 0.001), BV (r{sub S} = 0.849, p < 0.001) and PS (r{sub S} = 0.761, p < 0.001). Conclusions: We presented a database of the SPV for the esophageal cancer and proved that SPV of the esophageal neoplasm significantly differs from the SPV of the skeletal muscle, which represented a sample of healthy

  9. Magnetic resonance perfusion imaging evaluation in perfusion abnormalities of the cerebellum after supratentorial unilateral hyperacute cerebral infarction

    Institute of Scientific and Technical Information of China (English)

    Pan Liang; Yunjun Yang; Weijian Chen; Yuxia Duan; Hongqing Wang; Xiaotong Wang

    2012-01-01

    Magnetic resonance imaging (MRI) data of 10 patients with hyperacute cerebral infarction (≤ 6 hours) were retrospectively analyzed. Six patients exhibited perfusion defects on negative enhancement integral maps, four patients exhibited perfusion differences in pseudo-color on mean time to enhance maps, and three patients exhibited perfusion differences in pseudo-color on time to minimum maps. Dynamic susceptibility contrast-enhanced perfusion weighted imaging revealed a significant increase in region negative enhancement integral in the affected hemisphere of patients with cerebral infarction. The results suggest that dynamic susceptibility contrast-enhanced perfusion weighted imaging can clearly detect perfusion abnormalities in the cerebellum after unilateral hyperacute cerebral infarction.

  10. Recent Advances in Applications of Droplet Microfluidics

    Directory of Open Access Journals (Sweden)

    Wei-Lung Chou

    2015-09-01

    Full Text Available Droplet-based microfluidics is a colloidal and interfacial system that has rapidly progressed in the past decade because of the advantages of low fabrication costs, small sample volumes, reduced analysis durations, high-throughput analysis with exceptional sensitivity, enhanced operational flexibility, and facile automation. This technology has emerged as a new tool for many recently used applications in molecular detection, imaging, drug delivery, diagnostics, cell biology and other fields. Herein, we review recent applications of droplet microfluidics proposed since 2013.

  11. Microfluidic chip-capillary electrophoresis devices

    CERN Document Server

    Fung, Ying Sing; Du, Fuying; Guo, Wenpeng; Ma, Tongmei; Nie, Zhou; Sun, Hui; Wu, Ruige; Zhao, Wenfeng

    2015-01-01

    Capillary electrophoresis (CE) and microfluidic chip (MC) devices are relatively mature technologies, but this book demonstrates how they can be integrated into a single, revolutionary device that can provide on-site analysis of samples when laboratory services are unavailable. By introducing the combination of CE and MC technology, Microfluidic Chip-Capillary Electrophoresis Devices broadens the scope of chemical analysis, particularly in the biomedical, food, and environmental sciences.The book gives an overview of the development of MC and CE technology as well as technology that now allows

  12. Integrated Microfluidic Sensor System with Magnetostrictive Resonators

    KAUST Repository

    Liang, Cai

    2011-12-08

    The present embodiments describe a method that integrates a magnetostrictive sensor with driving and detecting elements into a microfluidic chip to detect a chemical, biochemical or biomedical species. These embodiments may also measure the properties of a fluid such as viscosity, pH values. The whole system can be referred to lab-on-a-chip (LOC) or micro-total-analysis-systems (.mu.TAS). In particular, this present embodiments include three units, including a microfluidics unit, a magnetostrictive sensor, and driving/detecting elements. An analyzer may also be provided to analyze an electrical signal associated with a feature of a target specimen.

  13. Microfluidic Assessment of Frying Oil Degradation

    Science.gov (United States)

    Liu, Mei; Xie, Shaorong; Ge, Ji; Xu, Zhensong; Wu, Zhizheng; Ru, Changhai; Luo, Jun; Sun, Yu

    2016-01-01

    Monitoring the quality of frying oil is important for the health of consumers. This paper reports a microfluidic technique for rapidly quantifying the degradation of frying oil. The microfluidic device generates monodispersed water-in-oil droplets and exploits viscosity and interfacial tension changes of frying oil samples over their frying/degradation process. The measured parameters were correlated to the total polar material percentage that is widely used in the food industry. The results reveal that the steady-state length of droplets can be used for unambiguously assessing frying oil quality degradation. PMID:27312884

  14. Microfluidic fuel cells for energy generation.

    Science.gov (United States)

    Safdar, M; Jänis, J; Sánchez, S

    2016-08-01

    Sustainable energy generation is of recent interest due to a growing energy demand across the globe and increasing environmental issues caused by conventional non-renewable means of power generation. In the context of microsystems, portable electronics and lab-on-a-chip based (bio)chemical sensors would essentially require fully integrated, reliable means of power generation. Microfluidic-based fuel cells can offer unique advantages compared to conventional fuel cells such as high surface area-to-volume ratio, ease of integration, cost effectiveness and portability. Here, we summarize recent developments which utilize the potential of microfluidic devices for energy generation. PMID:27367869

  15. Droplet actuation in an electrified microfluidic network.

    Science.gov (United States)

    Wehking, Jonathan D; Kumar, Ranganathan

    2015-02-01

    This work demonstrates that liquid droplet emulsions in a microchannel can be deformed, decelerated and/or pinned by applying a suitable electrical potential. By concentrating a potential gradient at the corners, we show that different droplets can be passively binned by size and on demand in a branched microfluidic device. The deformation, deceleration, squeezing and release of droplets in a three-dimensional numerical simulation are qualitatively verified by experiments in a PDMS microfluidic device. The forces required for pinning or binning a droplet provide a delicate balance between hydrodynamics and the electric field, and are obtained using appropriate non-dimensional parameters. PMID:25435073

  16. Physics and applications of microfluidics in biology.

    Science.gov (United States)

    Beebe, David J; Mensing, Glennys A; Walker, Glenn M

    2002-01-01

    Fluid flow at the microscale exhibits unique phenomena that can be leveraged to fabricate devices and components capable of performing functions useful for biological studies. The physics of importance to microfluidics are reviewed. Common methods of fabricating microfluidic devices and systems are described. Components, including valves, mixers, and pumps, capable of controlling fluid flow by utilizing the physics of the microscale are presented. Techniques for sensing flow characteristics are described and examples of devices and systems that perform bioanalysis are presented. The focus of this review is microscale phenomena and the use of the physics of the scale to create devices and systems that provide functionality useful to the life sciences.

  17. Diffusion dynamics in microfluidic dye lasers

    DEFF Research Database (Denmark)

    Gersborg-Hansen, Morten; Balslev, Søren; Mortensen, Niels Asger;

    2007-01-01

    We have investigated the bleaching dynamics that occur in opto-fluidic dye lasers, where the liquid laser dye in a channel is locally bleached due to optical pumping. Our studies suggest that for micro-fluidic devices, the dye bleaching may be compensated through diffusion of dye molecules alone....... By relying on diffusion rather than convection to generate the necessary dye replenishment, our observation potentially allows for a significant simplification of opto-fluidic dye laser device layouts, omitting the need for cumbersome and costly external fluidic handling or on-chip micro-fluidic pumping...

  18. Microfluidic Assessment of Frying Oil Degradation

    Science.gov (United States)

    Liu, Mei; Xie, Shaorong; Ge, Ji; Xu, Zhensong; Wu, Zhizheng; Ru, Changhai; Luo, Jun; Sun, Yu

    2016-06-01

    Monitoring the quality of frying oil is important for the health of consumers. This paper reports a microfluidic technique for rapidly quantifying the degradation of frying oil. The microfluidic device generates monodispersed water-in-oil droplets and exploits viscosity and interfacial tension changes of frying oil samples over their frying/degradation process. The measured parameters were correlated to the total polar material percentage that is widely used in the food industry. The results reveal that the steady-state length of droplets can be used for unambiguously assessing frying oil quality degradation.

  19. Detection methods for centrifugal microfluidic platforms.

    Science.gov (United States)

    Burger, Robert; Amato, Letizia; Boisen, Anja

    2016-02-15

    Centrifugal microfluidics has attracted much interest from academia as well as industry, since it potentially offers solutions for affordable, user-friendly and portable biosensing. A wide range of so-called fluidic unit operations, e.g. mixing, metering, liquid routing, and particle separation, have been developed and allow automation and integration of complex assay protocols in lab-on-a-disc systems. Besides liquid handling, the detection strategy for reading out the assay is crucial for developing a fully integrated system. In this review, we focus on biosensors and readout methods for the centrifugal microfluidics platform and cover optical as well as mechanical and electrical detection principles.

  20. Perfusion computed tomography for diffuse liver diseases; Perfusions-CT bei diffusen Lebererkrankungen

    Energy Technology Data Exchange (ETDEWEB)

    Schmidt, S.A.; Juchems, M.S. [Universitaetsklinikum Ulm, Klinik fuer Diagnostische und Interventionelle Radiologie, Ulm (Germany)

    2012-08-15

    Perfusion computed tomography (CT) has its main application in the clinical routine diagnosis of neuroradiological problems. Polyphase multi-detector spiral computed tomography is primarily used in liver diagnostics. The use of perfusion CT is also possible for the diagnostics and differentiation of diffuse hepatic diseases. The differentiation between cirrhosis and cirrhosis-like parenchymal changes is possible. It also helps to detect early stages of malignant tumors. However, there are some negative aspects, particularly that of radiation exposure. This paper summarizes the technical basics and possible applications of perfusion CT in cases of diffuse liver disease and weighs up the advantages and disadvantages of the examinations. (orig.) [German] Die Perfusions-CT hat ihren hauptsaechlichen Stellenwert bislang in der klinischen Routinediagnostik bei neuroradiologische Fragestellungen. In der Leberdiagnostik kommt v. a. die mehrphasige Multidetektor-Spiral-CT-Untersuchung zum Einsatz. Die Anwendung der Perfusions-CT ist auch bei der Diagnostik und Differenzierung diffuser Lebererkrankungen moeglich. Die Unterscheidung zwischen einer Leberzirrhose und zirrhoseaehnlichen Parenchymveraenderungen ist mit der Perfusions-CT moeglich. Ebenso liefert sie einen wertvollen Beitrag zur Diagnostik bei der Frueherkennung entstehender maligner Herdbefunde. Diesen Vorteilen stehen jedoch auch einige negative Aspekte gegenueber, insbesondere die relativ hohe Strahlenexposition. Die vorliegende Arbeit soll einen Ueberblick ueber die technischen Grundlagen und die Anwendungsmoeglichkeiten der Perfusions-CT bei diffusen Lebererkrankungen geben sowie die Vor- und Nachteile der Untersuchung gegeneinander abwaegen. (orig.)

  1. Measurement of myocardial perfusion using magnetic resonance

    DEFF Research Database (Denmark)

    Fritz-Hansen, T.; Jensen, L.T.; Larsson, H.B.;

    2008-01-01

    Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper review...... myocardial perfusion imaging with MR contrast agents: methods, validation and experiences from clinical studies. Unresolved issues still restrict the use of these techniques to research although clinical applications are within reach Udgivelsesdato: 2008/12/8......Cardiac magnetic resonance imaging (MRI) has evolved rapidly. Recent developments have made non-invasive quantitative myocardial perfusion measurements possible. MRI is particularly attractive due to its high spatial resolution and because it does not involve ionising radiation. This paper reviews...

  2. Dynamic perfusion patterns in temporal lobe epilepsy

    Energy Technology Data Exchange (ETDEWEB)

    Dupont, Patrick; Paesschen, Wim van [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); Zaknun, John J. [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); University Hospital of Innsbruck, Department of Nuclear Medicine, Innsbruck (Austria); Maes, Alex [KU Leuven/UZ Gasthuisberg, Nuclear Medicine, Medical Imaging Center and Neurology, Leuven (Belgium); AZ Groeninge, Nuclear Medicine, Kortrijk (Belgium); Tepmongkol, Supatporn; Locharernkul, Chaichon [Chulalongkorn University, Nuclear Medicine and Neurology, Bangkok (Thailand); Vasquez, Silvia; Carpintiero, Silvina [Fleni Instituto de Investigaciones Neurologicas, Nuclear Medicine, Buenos Aires (Argentina); Bal, C.S. [All India Institute of Medical Sciences, Nuclear Medicine, New Delhi (India); Dondi, Maurizio [International Atomic Energy Agency (IAEA), Nuclear Medicine Section, Division of Human Health, Wagramer Strasse 5, PO BOX 200, Vienna (Austria); Ospedale Maggiore, Nuclear Medicine, Bologna (Italy)

    2009-05-15

    To investigate dynamic ictal perfusion changes during temporal lobe epilepsy (TLE). We investigated 37 patients with TLE by ictal and interictal SPECT. All ictal injections were performed within 60 s of seizure onset. Statistical parametric mapping was used to analyse brain perfusion changes and temporal relationships with injection time and seizure duration as covariates. The analysis revealed significant ictal hyperperfusion in the ipsilateral temporal lobe extending to subcortical regions. Hypoperfusion was observed in large extratemporal areas. There were also significant dynamic changes in several extratemporal regions: ipsilateral orbitofrontal and bilateral superior frontal gyri and the contralateral cerebellum and ipsilateral striatum. The study demonstrated early dynamic perfusion changes in extratemporal regions probably involved in both propagation of epileptic activity and initiation of inhibitory mechanisms. (orig.)

  3. Microfluidics' great promise for Biology - Microfluidics as a new engine for the molecular sciences

    KAUST Repository

    Kodzius, Rimantas

    2010-06-04

    History of the Life Sciences Origins of life Discoveries and instrumentation The power of genetic variation Diagnostics based on DNA/ protein variation Genomic scanning providers DNA sequencing companies Microfluidics story Commercial products available P

  4. Electrostatically Directed Self-Assembly of Ultrathin Supramolecular Polymer Microcapsules

    OpenAIRE

    Parker, Richard M.; Zhang, Jing; Zheng, Yu; Coulston, Roger J.; Smith, Clive A; Salmon, Andrew R; Yu, Ziyi; Oren A. Scherman; Abell, Chris

    2015-01-01

    Supramolecular self-assembly offers routes to challenging architectures on the molecular and macroscopic scale. Coupled with microfluidics it has been used to make microcapsules—where a 2D sheet is shaped in 3D, encapsulating the volume within. In this paper, a versatile methodology to direct the accumulation of capsule-forming components to the droplet interface using electrostatic interactions is described. In this approach, charged copolymers are selectively partitioned to the microdroplet...

  5. Perfusion CT in acute stroke; Stellenwert der CT-Perfusion fuer die Therapie des Schlaganfalls

    Energy Technology Data Exchange (ETDEWEB)

    Eckert, Bernd [Asklepios Klinik Altona (Germany). Radiologie und Neuroradiologie; Roether, Joachim [Asklepios Klinik Altona (Germany). Neurologische Abt.; Fiehler, Jens [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Neuroradiologische Diagnostik und Intervention; Thomalla, Goetz [Universitaetsklinikum Hamburg-Eppendorf, Hamburg (Germany). Klinik und Poliklinik fuer Neurologie, Kopf- und Neurozentrum

    2015-06-15

    Modern multislice CT scanners enable multimodal protocols including non-enhanced CT, CT angiography, and CT perfusion. A 64-slice CT scanner provides 4-cm coverage. To cover the whole brain, a 128 - 256-slice scanner is needed. The use of perfusion CT requires an optimized scan protocol in order to reduce exposure to radiation. As compared to non-enhanced CT and CT angiography, the use of CT perfusion increases detection rates of cerebral ischemia, especially small cortical ischemic lesions, while the detection of lacunar and infratentorial stroke lesions remains limited. Perfusion CT enables estimation of collateral flow in acute occlusion of large intra- or extracranial arteries. Currently, no established reliable thresholds are available for determining infarct core and penumbral tissue by CT perfusion. Moreover, perfusion parameters depend on the processing algorithms and the software used for calculation. However, a number of studies point towards a reduction of cerebral blood volume (CBV) below 2 ml/100 g as a critical threshold that identifies infarct core. Large CBV lesions are associated with poor outcome even in the context of recanalization. The extent of early ischemic signs on non-enhanced CT remains the main parameter from CT imaging to guide acute reperfusion treatment. Nevertheless, perfusion CT increases diagnostic and therapeutic certainty in the acute setting. Similar to stroke MRI, perfusion CT enables the identification of tissue at risk of infarction by the mismatch between infarct core and the larger area of critical hypoperfusion. Further insights into the validity of perfusion parameters are expected from ongoing trials of mechanical thrombectomy in stroke.

  6. Abnormal perfusion on myocardial perfusion SPECT in patients with Wolff-Parkinson-White syndrome

    Energy Technology Data Exchange (ETDEWEB)

    Kang, Do Young; Cha, Kwang Soo; Han, Seung Ho; Park, Tae Ho; Kim, Moo Hyun; Kim, Young Dae [Donga University College of Medicine, Busan (Korea, Republic of)

    2005-02-15

    Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkison-White) syndrome. Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECT with Fitzpatrick's algorithm of electrophysiologic study and radiofrequency catheter ablation. Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients(mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent (11.0 {+-} 8.5%, range:3 {approx} 35%) and mild to moderate severity (-71 {+-} 42.7%, range:-217 {approx} -39%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patients with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but if did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome.

  7. Abnormal perfusion on myocardial perfusion SPECT in patients with Wolff-Parkinson-White syndrome

    International Nuclear Information System (INIS)

    Abnormal myocardial perfusion may be caused by ventricular preexcitation, but its location, extent, severity and correlation with accessory pathway (AP) are not established. We evaluated perfusion patterns on myocardial perfusion SPECT and location of AP in patients with WPW (Wolff-Parkison-White) syndrome. Adenosine Tc-99m MIBI or Tl-201 myocardial perfusion SPECT was performed in 11 patients with WPW syndrome. Perfusion defects (PD) were compared to AP location based on ECT with Fitzpatrick's algorithm of electrophysiologic study and radiofrequency catheter ablation. Patients had atypical chest discomfort or no symptom. Risk of coronary artery disease (CAD) was below 0.1 in 11 patients using the nomogram to estimate the probability of CAD. Coronary angiography was performed in 4 patients(mid-LAD 50% in one, normal in others). In 4 patients, AP localization was done by electrophysiologic study and radiofrequency catheter ablation (RFCA). Small to large extent (11.0 ± 8.5%, range:3 ∼ 35%) and mild to moderate severity (-71 ± 42.7%, range:-217 ∼ -39%) of reversible (n=9) or fixed (n=1) perfusion defects were noted. One patients with right free wall (right lateral) AP showed normal. PD locations were variable following the location of AP. One patient with left lateral wall AP was followed 6 weeks after RFCA and showed significantly decreased PD on SPECT with successful ablation. Myocardial perfusion defect showed variable extent, severity and location in patients with WPW syndrome. Abnormal perfusion defect showed in most of all patients, but if did not seem to be correlated specifically with location of accessory pathway and coronary artery disease. Therefore myocardial perfusion SPECT should be interpreted carefully in patients with WPW syndrome

  8. Expanding Imaging Capabilities for Microfluidics: Applicability of Darkfield Internal Reflection Illumination (DIRI) to Observations in Microfluidics

    OpenAIRE

    Yoshihiro Kawano; Chino Otsuka; James Sanzo; Christopher Higgins; Tatsuo Nirei; Tobias Schilling; Takuji Ishikawa

    2015-01-01

    Microfluidics is used increasingly for engineering and biomedical applications due to recent advances in microfabrication technologies. Visualization of bubbles, tracer particles, and cells in a microfluidic device is important for designing a device and analyzing results. However, with conventional methods, it is difficult to observe the channel geometry and such particles simultaneously. To overcome this limitation, we developed a Darkfield Internal Reflection Illumination (DIRI) system tha...

  9. Optical fiber LPG biosensor integrated microfluidic chip for ultrasensitive glucose detection

    OpenAIRE

    Yin, Ming-Jie; Huang, Bobo; Gao, Shaorui; Zhang, A. Ping; Ye, Xuesong

    2016-01-01

    An optical fiber sensor integrated microfluidic chip is presented for ultrasensitive detection of glucose. A long-period grating (LPG) inscribed in a small-diameter single-mode fiber (SDSMF) is employed as an optical refractive-index (RI) sensor. With the layer-by-layer (LbL) self-assembly technique, poly (ethylenimine) (PEI) and poly (acrylic acid) (PAA) multilayer film is deposited on the SDSMF-LPG sensor for both supporting and signal enhancement, and then a glucose oxidase (GOD) layer is ...

  10. Microfluidic actuation of insulating liquid droplets in a parallel-plate device

    International Nuclear Information System (INIS)

    In droplet-based microfluidics, the simultaneous movement and manipulation of dielectric and aqueous droplets on a single platform is important. The actuation forces on both dielectric and aqueous droplets can be calculated with an electromechanical model using an equivalent RC circuit. This model predicts that dielectric droplet actuation can be made compatible with electrowetting-based water droplet manipulation if the oil droplet is immersed in water. Operations such as transporting, splitting, merging, and dispensing of dielectric droplets at voltages less than 100 V are demonstrated in a parallel-plate structure. Such capability opens the way to fully automated assembly line formation of single-emulsion droplets.

  11. A simple microfluidic Coriolis effect flowmeter for operation at high pressure and high temperature

    Science.gov (United States)

    Harrison, Christopher; Jundt, Jacques

    2016-08-01

    We describe a microfluidic Coriolis effect flowmeter that is simple to assemble, operates at elevated temperature and pressure, and can be operated with a lock-in amplifier. The sensor has a flow rate sensitivity greater than 2° of phase shift per 1 g/min of mass flow and is benchmarked with flow rates ranging from 0.05 to 2.0 g/min. The internal volume is 15 μl and uses off-the-shelf optical components to measure the tube motion. We demonstrate that fluid density can be calculated from the frequency of the resonating element with proper calibration.

  12. A simple microfluidic Coriolis effect flowmeter for operation at high pressure and high temperature.

    Science.gov (United States)

    Harrison, Christopher; Jundt, Jacques

    2016-08-01

    We describe a microfluidic Coriolis effect flowmeter that is simple to assemble, operates at elevated temperature and pressure, and can be operated with a lock-in amplifier. The sensor has a flow rate sensitivity greater than 2° of phase shift per 1 g/min of mass flow and is benchmarked with flow rates ranging from 0.05 to 2.0 g/min. The internal volume is 15 μl and uses off-the-shelf optical components to measure the tube motion. We demonstrate that fluid density can be calculated from the frequency of the resonating element with proper calibration.

  13. A radio frequency device for measurement of minute dielectric property changes in microfluidic channels

    Science.gov (United States)

    Song, Chunrong; Wang, Pingshan

    2009-01-01

    We demonstrate a sensitive radio frequency (rf) device to detect small dielectric property changes in microfluidic channel. The device consists of an on-chip Wilkinson power divider and a rat-race hybrid, which are built with planar microstrip lines and thin film chip resistors. Interference is used to cancel parasitic background signals. As a result, the measurement sensitivity is improved by more than 20 dB compared with conventional transmission lines. Compared with an ultrasensitive slot antenna/cuvette assembly [K. M. Taylor and D. W. van der Weide, IEEE Trans. Microwave Theory Tech. 53, 1576 (2005)], the proposed rf device is two times more sensitive.

  14. Ventilation-perfusion scintigraphy in pulmonary disease

    International Nuclear Information System (INIS)

    A program for ventilation-perfusion imaging is described. It is suitable for routine use and comprises defined image masking and normalized matrix division. Three cases are reported from more than eighty in which VP imaging was performed. The findings show that the mask technique enables perfusion defects to be topographically outlined from the ventilatory distribution. Furthermore it is demonstrated that the mask technique can even be applied to sequential studies characterized by marked air trapping. The functional images are generated quickly enough even for emergency use. (Auth.)

  15. Ventilation-perfusion distribution in normal subjects

    OpenAIRE

    Beck, Kenneth C.; Johnson, Bruce D.; Olson, Thomas P.; Wilson, Theodore A.

    2012-01-01

    Functional values of LogSD of the ventilation distribution (σV̇) have been reported previously, but functional values of LogSD of the perfusion distribution (σq̇) and the coefficient of correlation between ventilation and perfusion (ρ) have not been measured in humans. Here, we report values for σV̇, σq̇, and ρ obtained from wash-in data for three gases, helium and two soluble gases, acetylene and dimethyl ether. Normal subjects inspired gas containing the test gases, and the concentrations o...

  16. Improved visualization of delayed perfusion in lung MRI

    Energy Technology Data Exchange (ETDEWEB)

    Risse, Frank [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Eichinger, Monika [Department of Radiology, German Cancer Research Center, Heidelberg (Germany); Kauczor, Hans-Ulrich [Department of Diagnostic and Interventional Radiology, University Hospital Heidelberg, Heidelberg (Germany); Semmler, Wolfhard [Department of Medical Physics in Radiology, German Cancer Research Center, Heidelberg (Germany); Puderbach, Michael, E-mail: m.puderbach@dkfz.de [Department of Radiology, German Cancer Research Center, Heidelberg (Germany)

    2011-01-15

    Introduction: The investigation of pulmonary perfusion by three-dimensional (3D) dynamic contrast-enhanced magnetic resonance imaging (DCE-MRI) was proposed recently. Subtraction images are generated for clinical evaluation, but temporal information is lost and perfusion defects might therefore be masked in this process. The aim of this study is to demonstrate a simple analysis strategy and classification for 3D-DCE-MRI perfusion datasets in the lung without omitting the temporal information. Materials and methods: Pulmonary perfusion measurements were performed in patients with different lung diseases using a 1.5 T MR-scanner with a time-resolved 3D-GRE pulse sequence. 25 3D-volumes were acquired after iv-injection of 0.1 mmol/kg KG Gadolinium-DTPA. Three parameters were determined for each pixel: (1) peak enhancement S{sub n,max} normalized to the arterial input function to detect regions of reduced perfusion; (2) time between arterial peak enhancement in the large pulmonary artery and tissue peak enhancement {tau} to visualize regions with delayed bolus onset; and (3) ratio R = S{sub n,max}/{tau} was calculated to visualize impaired perfusion, irrespectively of whether related to reduced or delayed perfusion. Results: A manual selection of peak perfusion images is not required. Five different types of perfusion can be found: (1) normal perfusion; (2) delayed non-reduced perfusion; (3) reduced non-delayed perfusion; (4) reduced and delayed perfusion; and (5) no perfusion. Types II and IV could not be seen in subtraction images since the temporal information is necessary for this purpose. Conclusions: The analysis strategy in this study allows for a simple and observer-independent visualization and classification of impaired perfusion in dynamic contrast-enhanced pulmonary perfusion MRI by using the temporal information of the datasets.

  17. [Design of the Rolling Type Nasal Feeding Perfusion Apparatus].

    Science.gov (United States)

    Yu, Dong; Yang, Yonghuan; Hu, Huiqin; Luo, Hongjun; Feng, Yunhao; Hao, Xiali

    2015-09-01

    At present, the existing problem in nasal feeding perfusion apparatus is laborious and instability. Designing the rolling type perfusion apparatus by using a roller pump, the problem is solved. Compared with the traditional perfusion apparatus, the advantage lies in liquid carrying only need once and simulating human swallowing process. Through testing and verification, the apparatus can be used in nasal feeding perfusion for elderly or patients.

  18. Computer-assisted ex vivo, normothermic small bowel perfusion

    OpenAIRE

    Stangl, M.J.; Krapp, J.; Theodorou, D; Eder, M.; Hammer, C; Land, W.; Schildberg, Friedrich Wilhelm

    2000-01-01

    Background: In the present study, a technique for computer-assisted, normothermic, oxygenated, ex vivo, recirculating small bowel perfusion was established as a tool to investigate organ pretreatment protocols and ischemia/reperfusion phenomena. A prerequisite for the desired setup was an organ chamber for ex vivo perfusion and the use of syngeneic whole blood as perfusate. Methods: The entire small bowel was harvested from Lewis rats and perfused in an organ chamber ex vivo for at least 2 h....

  19. Differential protein expression in perfusates from metastasized rat livers

    OpenAIRE

    Zhang, Yang; Li, Menglin; Wei, Lilong; Zhu, Lisi; Hu, Siqi; Wu, Shuzhen; Ma, Sucan; Gao, Youhe

    2013-01-01

    Background Liver perfusates exhibit theoretical advantages regarding the discovery of disease biomarkers because they contain proteins that readily enter the blood-stream, and perfusion preserves the disease state in its natural context. The purpose of the study is to explore the value of liver perfusate proteome in the biomarker discovery of liver diseases. Results In this study, 86 differentially expressed proteins were identified in perfusates from isolated rat livers metastasized by Walke...

  20. Optical fiber LPG biosensor integrated microfluidic chip for ultrasensitive glucose detection.

    Science.gov (United States)

    Yin, Ming-Jie; Huang, Bobo; Gao, Shaorui; Zhang, A Ping; Ye, Xuesong

    2016-05-01

    An optical fiber sensor integrated microfluidic chip is presented for ultrasensitive detection of glucose. A long-period grating (LPG) inscribed in a small-diameter single-mode fiber (SDSMF) is employed as an optical refractive-index (RI) sensor. With the layer-by-layer (LbL) self-assembly technique, poly (ethylenimine) (PEI) and poly (acrylic acid) (PAA) multilayer film is deposited on the SDSMF-LPG sensor for both supporting and signal enhancement, and then a glucose oxidase (GOD) layer is immobilized on the outer layer for glucose sensing. A microfluidic chip for glucose detection is fabricated after embedding the SDSMF-LPG biosensor into the microchannel of the chip. Experimental results reveal that the SDSMF-LPG biosensor based on such a hybrid sensing film can ultrasensitively detect glucose concentration as low as 1 nM. After integration into the microfluidic chip, the detection range of the sensor is extended from 2 µM to 10 µM, and the response time is remarkablely shortened from 6 minutes to 70 seconds.

  1. Optical fiber LPG biosensor integrated microfluidic chip for ultrasensitive glucose detection.

    Science.gov (United States)

    Yin, Ming-Jie; Huang, Bobo; Gao, Shaorui; Zhang, A Ping; Ye, Xuesong

    2016-05-01

    An optical fiber sensor integrated microfluidic chip is presented for ultrasensitive detection of glucose. A long-period grating (LPG) inscribed in a small-diameter single-mode fiber (SDSMF) is employed as an optical refractive-index (RI) sensor. With the layer-by-layer (LbL) self-assembly technique, poly (ethylenimine) (PEI) and poly (acrylic acid) (PAA) multilayer film is deposited on the SDSMF-LPG sensor for both supporting and signal enhancement, and then a glucose oxidase (GOD) layer is immobilized on the outer layer for glucose sensing. A microfluidic chip for glucose detection is fabricated after embedding the SDSMF-LPG biosensor into the microchannel of the chip. Experimental results reveal that the SDSMF-LPG biosensor based on such a hybrid sensing film can ultrasensitively detect glucose concentration as low as 1 nM. After integration into the microfluidic chip, the detection range of the sensor is extended from 2 µM to 10 µM, and the response time is remarkablely shortened from 6 minutes to 70 seconds. PMID:27231643

  2. A microfluidic device integrating plasmonic nanodevices for Raman spectroscopy analysis on trapped single living cells

    KAUST Repository

    Perozziello, Gerardo

    2013-11-01

    In this work we developed a microfluidic device integrating nanoplasmonic devices combined with fluidic trapping regions. The microfuidic traps allow to capture single cells in areas where plasmonic sensors are placed. In this way it is possible to perform Enhanced Raman analysis on the cell membranes. Moreover, by changing direction of the flux it is possible to change the orientation of the cell in the trap, so that it is possible to analyze different points of the membrane of the same cell. We shows an innovative procedure to fabricate and assembly the microfluidic device which combine photolithography, focused ion beam machining, and hybrid bonding between a polymer substrate and lid of Calcium fluoride. This procedure is compatible with the fabrication of the plasmonic sensors in close proximity of the microfluidic traps. Moreover, the use of Calcium fluoride as lid allows full compatibility with Raman measurements producing negligible Raman background signal and avoids Raman artifacts. Finally, we performed Raman analysis on cells to monitor their oxidative stress under particular non physiological conditions. © 2013 Elsevier B.V. All rights reserved.

  3. Perfusion MRI in neuro-psychiatric systemic lupus erthemathosus.

    NARCIS (Netherlands)

    Emmer, B.J.; Osch, M.J. van; Wu, O.; Steup-Beekman, G.M.; Steens, S.; Huizinga, T.W.J.; Buchem, M.A. van; Grond, J. van der

    2010-01-01

    PURPOSE: To use perfusion weighted MR to quantify any perfusion abnormalities and to determine their contribution to neuropsychiatric (NP) involvement in systemic lupus erythematosus (SLE). MATERIALS AND METHODS: We applied dynamic susceptibility contrast (DSC) perfusion MRI in 15 active NPSLE, 26 i

  4. Computed tomography perfusion evaluation after extracranial-intracranial bypass surgery

    NARCIS (Netherlands)

    Vos, Pieter C.; Riordan, Alan J.; Smit, Ewoud J.; de Jong, Hugo W. A. M.; van der Zwan, Albert; Velthuis, BK; Viergever, Max A.; Dankbaar, Jan Willem

    2015-01-01

    Objective: Perfusion imaging is increasingly used for postoperative evaluation of extracranial to intracranial (EC-IC) bypass surgery. Altered hemodynamics and delayed arrival of the contrast agent in the area fed by the bypass can influence perfusion measurement. We compared perfusion asymmetry obt

  5. Computed tomography perfusion evaluation after extracranial-intracranial bypass surgery

    NARCIS (Netherlands)

    Vos, P.C.; Riordan, A.J.; Smit, E.J.; Jong, H.W. de; Zwan, A. van der; Velthuis, B.K.; Viergever, M.A.; Dankbaar, J.W.

    2015-01-01

    OBJECTIVE: Perfusion imaging is increasingly used for postoperative evaluation of extracranial to intracranial (EC-IC) bypass surgery. Altered hemodynamics and delayed arrival of the contrast agent in the area fed by the bypass can influence perfusion measurement. We compared perfusion asymmetry obt

  6. CT angiography and CT perfusion in acute ischemic stroke

    NARCIS (Netherlands)

    Seeters, T. van

    2016-01-01

    CT angiography and CT perfusion are used in patients with acute ischemic stroke for diagnostic purposes and to select patients for treatment. In this thesis, the reproducibility of CT angiography and CT perfusion is examined, the additional value of CT angiography and CT perfusion for stroke outcome

  7. Differential white cell count by centrifugal microfluidics.

    Energy Technology Data Exchange (ETDEWEB)

    Sommer, Gregory Jon; Tentori, Augusto M.; Schaff, Ulrich Y.

    2010-07-01

    We present a method for counting white blood cells that is uniquely compatible with centrifugation based microfluidics. Blood is deposited on top of one or more layers of density media within a microfluidic disk. Spinning the disk causes the cell populations within whole blood to settle through the media, reaching an equilibrium based on the density of each cell type. Separation and fluorescence measurement of cell types stained with a DNA dye is demonstrated using this technique. The integrated signal from bands of fluorescent microspheres is shown to be proportional to their initial concentration in suspension. Among the current generation of medical diagnostics are devices based on the principle of centrifuging a CD sized disk functionalized with microfluidics. These portable 'lab on a disk' devices are capable of conducting multiple assays directly from a blood sample, embodied by platforms developed by Gyros, Samsung, and Abaxis. [1,2] However, no centrifugal platform to date includes a differential white blood cell count, which is an important metric complimentary to diagnostic assays. Measuring the differential white blood cell count (the relative fraction of granulocytes, lymphocytes, and monocytes) is a standard medical diagnostic technique useful for identifying sepsis, leukemia, AIDS, radiation exposure, and a host of other conditions that affect the immune system. Several methods exist for measuring the relative white blood cell count including flow cytometry, electrical impedance, and visual identification from a stained drop of blood under a microscope. However, none of these methods is easily incorporated into a centrifugal microfluidic diagnostic platform.

  8. Application of membrane technology in microfluidic devices

    NARCIS (Netherlands)

    Jong, de Jorrit

    2008-01-01

    This thesis describes the application of membrane technology in microfluidic systems. The word ‘microfluidic’ refers to the research field that develops methods and devices to control, manipulate, and analyze flows in sub‐millimeter dimensions. General advantages of this miniaturization strategy inc

  9. High content screening in microfluidic devices

    Science.gov (United States)

    Cheong, Raymond; Paliwal, Saurabh; Levchenko, Andre

    2011-01-01

    Importance of the field Miniaturization is key to advancing the state-of-the-art in high content screening (HCS), in order to enable dramatic cost savings through reduced usage of expensive biochemical reagents and to enable large-scale screening on primary cells. Microfluidic technology offers the potential to enable HCS to be performed with an unprecedented degree of miniaturization. Areas covered in this review This perspective highlights a real-world example from the authors’ work of HCS assays implemented in a highly miniaturized microfluidic format. Advantages of this technology are discussed, including cost savings, high throughput screening on primary cells, improved accuracy, the ability to study complex time-varying stimuli, and ease of automation, integration, and scaling. What the reader will gain The reader will understand the capabilities of a new microfluidics-based platform for HCS, and the advantages it provides over conventional plate-based HCS. Take home message Microfluidics technology will drive significant advancements and broader usage and applicability of HCS in drug discovery. PMID:21852997

  10. Nanostructures for all-polymer microfluidic systems

    DEFF Research Database (Denmark)

    Matschuk, Maria; Bruus, Henrik; Larsen, Niels Bent

    2010-01-01

    antistiction coating was found to improve the replication fidelity (shape and depth) of nanoscale features substantially. Arrays of holes of 50 nm diameter/35 nm depth and 100 nm/100 nm diameter, respectively, were mass-produced in cyclic olefin copolymer (Topas 5013) by injection molding. Polymer microfluidic...

  11. Inventions Utilizing Microfluidics and Colloidal Particles

    Science.gov (United States)

    Marr, David W.; Gong, Tieying; Oakey, John; Terray, Alexander V.; Wu, David T.

    2009-01-01

    Several related inventions pertain to families of devices that utilize microfluidics and/or colloidal particles to obtain useful physical effects. The families of devices can be summarized as follows: (1) Microfluidic pumps and/or valves wherein colloidal-size particles driven by electrical, magnetic, or optical fields serve as the principal moving parts that propel and/or direct the affected flows. (2) Devices that are similar to the aforementioned pumps and/or valves except that they are used to manipulate light instead of fluids. The colloidal particles in these devices are substantially constrained to move in a plane and are driven to spatially order them into arrays that function, variously, as waveguides, filters, or switches for optical signals. (3) Devices wherein the ultra-laminar nature of microfluidic flows is exploited to effect separation, sorting, or filtering of colloidal particles or biological cells in suspension. (4) Devices wherein a combination of confinement and applied electrical and/or optical fields forces the colloidal particles to become arranged into three-dimensional crystal lattices. Control of the colloidal crystalline structures could be exploited to control diffraction of light. (5) Microfluidic devices, incorporating fluid waveguides, wherein switching of flows among different paths would be accompanied by switching of optical signals.

  12. Micromechanical photothermal analyser of microfluidic samples

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to a micromechanical photothermal analyser of microfluidic samples comprising an oblong micro-channel extending longitudinally from a support element, the micro-channel is made from at least two materials with different thermal expansion coefficients, wherein the...

  13. Wax-bonding 3D microfluidic chips

    KAUST Repository

    Gong, Xiuqing

    2013-10-10

    We report a simple, low-cost and detachable microfluidic chip incorporating easily accessible paper, glass slides or other polymer films as the chip materials along with adhesive wax as the recycling bonding material. We use a laser to cut through the paper or film to form patterns and then sandwich the paper and film between glass sheets or polymer membranes . The hot-melt adhesive wax can realize bridge bonding between various materials, for example, paper, polymethylmethacrylate (PMMA) film, glass sheets, or metal plate. The bonding process is reversible and the wax is reusable through a melting and cooling process. With this process, a three-dimensional (3D) microfluidic chip is achievable by vacuating and venting the chip in a hot-water bath. To study the biocompatibility and applicability of the wax-based microfluidic chip, we tested the PCR compatibility with the chip materials first. Then we applied the wax-paper based microfluidic chip to HeLa cell electroporation (EP ). Subsequently, a prototype of a 5-layer 3D chip was fabricated by multilayer wax bonding. To check the sealing ability and the durability of the chip, green fluorescence protein (GFP) recombinant Escherichia coli (E. coli) bacteria were cultured, with which the chemotaxis of E. coli was studied in order to determine the influence of antibiotic ciprofloxacin concentration on the E. coli migration.

  14. Biocatalytic process development using microfluidic miniaturized systems

    DEFF Research Database (Denmark)

    Krühne, Ulrich; Heintz, Søren; Ringborg, Rolf Hoffmeyer;

    2014-01-01

    The increasing interest in biocatalytic processes means there is a clear need for a new systematic development paradigm which encompasses both protein engineering and process engineering. This paper argues that through the use of a new microfluidic platform, data can be collected more rapidly and...

  15. Designing Polymeric Microfluidic Platforms for Biomedical Applications

    DEFF Research Database (Denmark)

    Vedarethinam, Indumathi

    Micro- and Nanotechnology have the potential to offer a smart solution for diagnostics and academia research with rapid, low cost, robust analysis systems to facilitate biological analyses. New, high throughput microfluidic platforms have the potential to surpass in performance the conventional a...

  16. Design of microfluidic bioreactors using topology optimization

    DEFF Research Database (Denmark)

    Okkels, Fridolin; Bruus, Henrik

    2007-01-01

    We address the design of optimal reactors for supporting biological cultures using the method of topology optimization. For some years this method have been used to design various optimal microfluidic devices.1-4 We apply this method to distribute optimally biologic cultures within a flow of nutr...

  17. Microfluidic desalination techniques and their potential applications

    NARCIS (Netherlands)

    Roelofs, S.H.; Berg, van den A.; Odijk, M.

    2015-01-01

    In this review we discuss recent developments in the emerging research field of miniaturized desalination. Traditionally desalination is performed to convert salt water into potable water and research is focused on improving performance of large-scale desalination plants. Microfluidic desalination o

  18. Understanding cell passage through constricted microfluidic channels

    Science.gov (United States)

    Cartas-Ayala, Marco A.; Karnik, Rohit

    2012-11-01

    Recently, several microfluidic platforms have been proposed to characterize cells based on their behaviour during cell passage through constricted channels. Variables like transit time have been analyzed in disease states like sickle cell anemia, malaria and sepsis. Nevertheless, it is hard to make direct comparisons between different platforms and cell types. We present experimental results of the relationship between solid deformable particle properties, i.e. stiffness and relative particle size, and flow properties, i.e. particle's velocity. We measured the hydrodynamic variables during the flow of HL-60 cells, a white myeloid cell type, in narrow microfluidic square channels using a microfluidic differential manometer. We measured the flow force required to move cells of different sizes through microchannels and quantified friction forces opposing cell passage. We determined the non-dimensional parameters that influence the flow of cells and we used them to obtain a non dimensional expression that can be used to predict the forces needed to drive cells through microchannels. We found that the friction force needed to flow HL-60 through a microfluidic channel is the sum of two parts. The first part is a static friction force that is proportional to the force needed to keep the force compressed. The second part is a factor that is proportional to the cell velocity, hence a dynamic term, and slightly sensitive to the compressive force. We thank CONACYT (Mexican Science and Technology Council) for supporting this project, grant 205899.

  19. Generation of emulsion droplets and micro-bubbles in microfluidic devices

    KAUST Repository

    Zhang, Jiaming

    2016-04-01

    Droplet-based microfluidic devices have become a preferred versatile platform for various fields in physics, chemistry and biology to manipulate small amounts of liquid samples. In addition to microdroplets, microbubbles are also needed for various pro- cesses in the food, healthcare and cosmetic industries. Polydimethylsiloxane (PDMS) soft lithography, the mainstay for fabricating microfluidic devices, usually requires the usage of expensive apparatus and a complex manufacturing procedure. In ad- dition, current methods have the limited capabilities for fabrication of microfluidic devices within three dimensional (3D) structures. Novel methods for fabrication of droplet-based microfluidic devices for the generation microdroplets and microbubbles are therefore of great interest in current research. In this thesis, we have developed several simple, rapid and low-cost methods for fabrication of microfluidic devices, especially for generation of microdroplets and mi- crobubbles. We first report an inexpensive full-glass microfluidic devices with as- sembly of glass capillaries, for generating monodisperse multiple emulsions. Different types of devices have been designed and tested and the experimental results demon- strated the robust capability of preparing monodisperse single, double, triple and multi-component emulsions. Second, we propose a similar full-glass device for generation of microbubbles, but with assembly of a much smaller nozzle of a glass capillary. Highly monodisperse microbubbles with diameter range from 3.5 to 60 microns have been successfully produced, at rates up to 40 kHz. A simple scaling law based on the capillary number and liquid-to-gas flow rate ratio, successfully predicts the bubble size. Recently, the emergent 3D printing technology provides an attractive fabrication technique, due to its simplicity and low cost. A handful of studies have already demonstrated droplet production through 3D-printed microfluidic devices. However, two

  20. Development of a Phantom Tissue for Blood Perfusion Measurements and Noninvasive Blood Perfusion Estimation in Living Tissue

    OpenAIRE

    Mudaliar, Ashvinikumar

    2007-01-01

    A convenient method for testing and calibrating surface perfusion sensors has been developed. A phantom tissue model is used to mimic the non-directional blood flow of tissue perfusion. A computational fluid dynamics (CFD) model was constructed in Fluent to design the phantom tissue and validate the experimental results. The phantom perfusion system was used with a perfusion sensor based on the clearance of thermal energy. A heat flux gage measures the heat flux response of tissue whe...

  1. From microfluidic modules to an integrated Lab-on-a-chip system for the detection of Francisella tularensis

    Science.gov (United States)

    Hlawatsch, Nadine; Krumbholz, Marco; Prüfer, Anna; Moche, Christian; Becker, Holger; Gärtner, Claudia

    2013-05-01

    Lab-on-a-chip (LoC) systems translating the whole process of pathogen analysis to an integrated, miniaturized, and automatically functioning microfluidic platform are generally expected to be very promising future diagnostic approaches. The development of such a LoC system for the detection of bacterial pathogens applied to the example pathogen Francisella tularensis is described in this report. To allow functional testing of the whole process cascade before final device integration, various bio-analytical steps such as cell lysis, DNA extraction and purification, continuous-flow PCR and analyte detection have been adapted to unique functional microfluidic modules. As a successive step, positively tested modules for pathogen detection have been successfully assembled to an integrated chip. Moreover, technical solutions for a smooth interaction between sample input from the outer world as well as microfluidic chip and chip driving instrument have been developed. In conclusion, a full repertoire of analytical tools have been developed and successfully tested in the concerted manner of a functionally integrated microfluidic device representing a tool for future diagnostic approaches.

  2. A rapid, straightforward, and print house compatible mass fabrication method for integrating 3D paper-based microfluidics.

    Science.gov (United States)

    Xiao, Liangpin; Liu, Xianming; Zhong, Runtao; Zhang, Kaiqing; Zhang, Xiaodi; Zhou, Xiaomian; Lin, Bingcheng; Du, Yuguang

    2013-11-01

    Three-dimensional (3D) paper-based microfluidics, which is featured with high performance and speedy determination, promise to carry out multistep sample pretreatment and orderly chemical reaction, which have been used for medical diagnosis, cell culture, environment determination, and so on with broad market prospect. However, there are some drawbacks in the existing fabrication methods for 3D paper-based microfluidics, such as, cumbersome and time-consuming device assembly; expensive and difficult process for manufacture; contamination caused by organic reagents from their fabrication process. Here, we present a simple printing-bookbinding method for mass fabricating 3D paper-based microfluidics. This approach involves two main steps: (i) wax-printing, (ii) bookbinding. We tested the delivery capability, diffusion rate, homogeneity and demonstrated the applicability of the device to chemical analysis by nitrite colorimetric assays. The described method is rapid (print house, making itself an ideal scheme for large-scale production of 3D paper-based microfluidics.

  3. Pulmonary artery perfusion versus no pulmonary perfusion during cardiopulmonary bypass in patients with COPD

    DEFF Research Database (Denmark)

    Buggeskov, Katrine B; Sundskard, Martin M; Jonassen, Thomas;

    2016-01-01

    INTRODUCTION: Absence of pulmonary perfusion during cardiopulmonary bypass (CPB) may be associated with reduced postoperative oxygenation. Effects of active pulmonary artery perfusion were explored in patients with chronic obstructive pulmonary disease (COPD) undergoing cardiac surgery. METHODS: 90...... starting CPB and longitudinally in a mixed-effects model (MEM). Secondary outcomes were tracheal intubation time, serious adverse events, mortality, days alive outside the intensive care unit (ICU) and outside the hospital. RESULTS: 21 hours after starting CPB patients receiving pulmonary artery perfusion...... with normothermic oxygenated blood had a higher oxygenation index compared with no pulmonary perfusion (mean difference (MD) 0.94; 95% CI 0.05 to 1.83; p=0.04). The blood group had also a higher oxygenation index both longitudinally (MEM, p=0.009) and at 21 hours (MD 0.99; CI 0.29 to 1.69; p=0.007) compared...

  4. Digital microfluidic operations on micro-electrode dot array architecture.

    Science.gov (United States)

    Wang, G; Teng, D; Fan, S-K

    2011-12-01

    As digital microfluidics-based biochips find more applications, their complexity is expected to increase significantly owing to the trend of multiple and concurrent assays on the chip. There is a pressing need to deliver a top-down design methodology that the biochip designer can leverage the same level of computer-aided design support as the semi-conductor industry now does. Moreover, as microelectronics fabrication technology is scaling up and integrated device performance is improving, it is expected that these microfluidic biochips will be integrated with microelectronic components in next-generation system-on-chip designs. This study presents the analysis and experiments of digital microfluidic operations on a novel electrowetting-on-dielectric-based 'micro-electrode dot array architecture' that fosters a development path for hierarchical top-down design approach for digital microfluidics. The proposed architecture allows dynamic configurations and activations of identical basic microfluidic unit called 'micro-electrode cells' to design microfluidic components, layouts, routing, microfluidic operations and applications of the biochip hierarchically. Fundamental microfluidic operations have been successfully performed by the architecture. In addition, this novel architecture demonstrates a number of advantages and flexibilities over the conventional digital microfluidics in performing advanced microfluidic operations. PMID:22149873

  5. Perfusion CT in Colorectal Cancer: Comparison of Perfusion Parameters with Tumor Grade and Microvessel Density

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jin Woong; Jeong, Yong Yeon; Chang, Nam Kyu; Heo, Suk Hee; Hur, Young Hoe; Kang, Heoung Keun [Chonnam National University Hwasun Hospital, Hwasun(Korea, Republic of); Shin, Sang Soo; Lee, Jae Hyuk [Chonnam National University Hospital, Gwangju (Korea, Republic of)

    2012-02-15

    The purpose of this study was to prospectively compare pre-operative computed tomography (CT) perfusion parameters with tumor grade from colorectal adenocarcinoma (CRC) and to correlate pre-operative CT perfusion parameters with microvessel density (MVD) to evaluate angiogenesis in CRC. Pre-operative perfusion CTs were performed with a 64-channel multidetector row CT in 27 patients (17 women and 10 men; age range 32-82 years) who were diagnosed with CRC involving the sigmoid and rectum between August 2006 and November 2007. All patients underwent surgery without pre-operative chemotherapy or radiation therapy. Dynamic perfusion CTs were performed for 65 seconds after intravenous injection of contrast medium (100 mL, 300 mg of iodine per mL, 5 mL/sec). Before surgery, blood flow (BF), blood volume, mean transit time (MTT), and permeability-surface area product were measured in the tumor. After surgery, one gastrointestinal pathologist evaluated tumor grade and performed immunohistochemical staining using CD 34 to determine MVD in each tumor. The Kruskal-Wallis test was used to compare CT perfusion parameters with tumor grade, and Pearson's correlation analysis was used to correlate CT perfusion parameters with MVD. In 27 patients with CRC, tumor grading was as follows: well differentiated (n = 8); moderately differentiated (n = 15); and poorly differentiated (n = 4). BF was higher in moderately differentiated CRC than well differentiated and poorly differentiated CRCs (p = 0.14). MTT was shorter in moderately differentiated than well differentiated and poorly differentiated CRCs (p = 0.039). The MVD was greater in poorly differentiated than well differentiated and moderately differentiated CRCs (p = 0.034). There was no significant correlation between other perfusion parameters and tumor grade. There was no significant correlation between CT perfusion parameters and MVD. BF and MTT measurement by perfusion CT is effective in predicting moderately differentiated CRCs

  6. Fast Registration of Cardiac Perfusion MRI

    DEFF Research Database (Denmark)

    Stegmann, Mikkel Bille; Larsson, Henrik B. W.

    2003-01-01

    This abstract presents a novel method for registration of cardiac perfusion MRI sequences. By performing complex analyses of variance and clustering in an annotated training set off-line, our method provides real-time segmentation in an on-line setting. This renders the method feasible for live...

  7. Asynchronicity of facial blood perfusion in migraine.

    Directory of Open Access Journals (Sweden)

    Nina Zaproudina

    Full Text Available Asymmetrical changes in blood perfusion and asynchronous blood supply to head tissues likely contribute to migraine pathophysiology. Imaging was widely used in order to understand hemodynamic variations in migraine. However, mapping of blood pulsations in the face of migraineurs has not been performed so far. We used the Blood Pulsation Imaging (BPI technique, which was recently developed in our group, to establish whether 2D-imaging of blood pulsations parameters can reveal new biomarkers of migraine. BPI characteristics were measured in migraineurs during the attack-free interval and compared to healthy subjects with and without a family history of migraine. We found a novel phenomenon of transverse waves of facial blood perfusion in migraineurs in contrast to healthy subjects who showed synchronous blood delivery to both sides of the face. Moreover, the amplitude of blood pulsations was symmetrically distributed over the face of healthy subjects, but asymmetrically in migraineurs and subjects with a family history of migraine. In the migraine patients we found a remarkable correlation between the side of unilateral headache and the direction of the blood perfusion wave. Our data suggest that migraine is associated with lateralization of blood perfusion and asynchronous blood pulsations in the facial area, which could be due to essential dysfunction of the autonomic vascular control in the face. These findings may further enhance our understanding of migraine pathophysiology and suggest new easily available biomarkers of this pathology.

  8. Study of lung perfusion in colagenosis

    International Nuclear Information System (INIS)

    The lung involvement in the various types of colagenosis has been widely described in the literature. However, the study of lung perfusion utilizing radionuclides has been only mentioned in a few papers. With the intention of ascertaining the importance of the lung perfusion scanning in colagenosis, ten cases were studied, seven of which were females and three males, with the following pathologies: 4 rheumatoid arthritis, 4 systemic lupus eritematosous, 1 scleroderma and 1 scleroderma plus dermatomyositis. The ages of the patients varied from 20 to 73 years, and the duration of the disease from 1 month to 39 years. The lung scanning showed perfusion defects in 100% of the cases, not related with the type of colagenosis, duration of the disease, sex or age. On the other hand, the X rays study showed alterations in only 2 patients (20% of the cases). The ventilatory and respiratory functions were tested on 7 patients showing alteration (mixed pattern with predominance of the restrictive factor) in only one (14.3%), while the other patients were normal (85.7%). The importance of the lung perfusion scanning study in all patients with collagen vascular diseases is emphasized. (author)

  9. Methodology for ventilation/perfusion SPECT

    DEFF Research Database (Denmark)

    Bajc, Marika; Neilly, Brian; Miniati, Massimo;

    2010-01-01

    Ventilation/perfusion single-photon emission computed tomography (V/Q SPECT) is the scintigraphic technique of choice for the diagnosis of pulmonary embolism and many other disorders that affect lung function. Data from recent ventilation studies show that the theoretic advantages of Technegas ov...

  10. Perfusion Quantification Using Gaussian Process Deconvolution

    DEFF Research Database (Denmark)

    Andersen, Irene Klærke; Have, Anna Szynkowiak; Rasmussen, Carl Edward;

    2002-01-01

    The quantification of perfusion using dynamic susceptibility contrast MRI (DSC-MRI) requires deconvolution to obtain the residual impulse response function (IRF). In this work, a method using the Gaussian process for deconvolution (GPD) is proposed. The fact that the IRF is smooth is incorporated...

  11. Clinical application of hepatic CT perfusion

    Institute of Scientific and Technical Information of China (English)

    Liang Zhong; Wen-Jing Wang; Jian-Rong Xu

    2009-01-01

    Complicated changes occur in hemodynamics of hepatic artery and vein, and portal vein under various kinds of pathologic status because of distinct double hepatic blood supply. This article reviews the clinical application of hepatic computed tomography perfusion in some liver diseases.

  12. Gradient-enhanced FAWSETS perfusion measurements

    Science.gov (United States)

    Marro, Kenneth I.; Lee, Donghoon; Hyyti, Outi M.

    2005-08-01

    This work describes the use of custom-built gradients to enhance skeletal muscle perfusion measurements acquired with a previously described arterial spin labeling technique known as FAWSETS (flow-driven arterial water stimulation with elimination of tissue signal). Custom-built gradients provide active control of the static magnetic field gradient on which FAWSETS relies for labeling. This allows selective, 180° modulations of the phase of the perfusion component of the signal. Phase cycling can then be implemented to eliminate all extraneous components leaving a signal that exclusively reflects capillary-level perfusion. Gradient-enhancement substantially reduces acquisition time and eliminates the need to acquire an ischemic signal to quantify perfusion. This removes critical obstacles to application of FAWSETS in organs other than skeletal muscle and makes the measurements more desirable for clinical environments. The basic physical principles of gradient-enhancement are demonstrated in flow phantom experiments and in vivo utility is demonstrated in rat hind limb during stimulated exercise.

  13. Interconnection blocks: a method for providing reusable, rapid, multiple, aligned and planar microfluidic interconnections

    DEFF Research Database (Denmark)

    Sabourin, David; Snakenborg, Detlef; Dufva, Hans Martin

    2009-01-01

    In this paper a method is presented for creating 'interconnection blocks' that are re-usable and provide multiple, aligned and planar microfluidic interconnections. Interconnection blocks made from polydimethylsiloxane allow rapid testing of microfluidic chips and unobstructed microfluidic...

  14. Furnace assembly

    Science.gov (United States)

    Panayotou, Nicholas F.; Green, Donald R.; Price, Larry S.

    1985-01-01

    A method of and apparatus for heating test specimens to desired elevated temperatures for irradiation by a high energy neutron source. A furnace assembly is provided for heating two separate groups of specimens to substantially different, elevated, isothermal temperatures in a high vacuum environment while positioning the two specimen groups symmetrically at equivalent neutron irradiating positions.

  15. Ventilation and perfusion display in a single image

    International Nuclear Information System (INIS)

    A new method of ventilation and perfusion display onto a single image is presented. From the data on regions of interest of the lungs, three-dimensional histograms are created, containing as parameters X and Y for the position of the pixels, Z for the perfusion and colour for local ventilation. The perfusion value is supplied by sets of curves having Z proportional to the local perfusion count rate. Ventilation modulates colour. Four perspective views of the histogram are simultaneously displayed to allow visualization of the entire organ. Information about the normal ranges for both ventilation and perfusion is also provided in the histograms. (orig.)

  16. DNA Assembly in 3D Printed Fluidics.

    Directory of Open Access Journals (Sweden)

    William G Patrick

    Full Text Available The process of connecting genetic parts-DNA assembly-is a foundational technology for synthetic biology. Microfluidics present an attractive solution for minimizing use of costly reagents, enabling multiplexed reactions, and automating protocols by integrating multiple protocol steps. However, microfluidics fabrication and operation can be expensive and requires expertise, limiting access to the technology. With advances in commodity digital fabrication tools, it is now possible to directly print fluidic devices and supporting hardware. 3D printed micro- and millifluidic devices are inexpensive, easy to make and quick to produce. We demonstrate Golden Gate DNA assembly in 3D-printed fluidics with reaction volumes as small as 490 nL, channel widths as fine as 220 microns, and per unit part costs ranging from $0.61 to $5.71. A 3D-printed syringe pump with an accompanying programmable software interface was designed and fabricated to operate the devices. Quick turnaround and inexpensive materials allowed for rapid exploration of device parameters, demonstrating a manufacturing paradigm for designing and fabricating hardware for synthetic biology.

  17. Operation placement for application-specific digital microfluidic biochips

    DEFF Research Database (Denmark)

    Alistar, Mirela; Pop, Paul; Madsen, Jan

    2013-01-01

    Microfluidic-based biochips are replacing the conventional biochemical analyzers, and are able to integrate onchip all the necessary functions for biochemical analysis using microfluidics. The digital microfluidic biochips are based on the manipulation of liquids not as a continuous flow, but as ......Microfluidic-based biochips are replacing the conventional biochemical analyzers, and are able to integrate onchip all the necessary functions for biochemical analysis using microfluidics. The digital microfluidic biochips are based on the manipulation of liquids not as a continuous flow...... work assumes that the biochip architecture is given, and consider a rectangular shape for the electrode array. However, non-regular application-specific architectures are common in practice. In this paper, we are interested in determining a placement of operations for application-specific biochips...

  18. Pulmonary ventilation and perfusion abnormalities and ventilation perfusion imbalance in children with pulmonary atresia or extreme tetralogy of Fallot

    International Nuclear Information System (INIS)

    Xenon-133 lung ventilation and perfusion scans were done preoperatively after cardiac catheterization and cineangiocardiography in 19 children; 6 had pulmonary atresia with an intact ventricular septum and hypoplastic right ventricle, 4 pulmonary atresia with associated complex univentricular heart, and 9 extreme Tetralogy of Fallot. The four patients with discrepancies in the sizes of the left and right pulmonary arteries on angiography had marked asymmetry of pulmonary perfusion and ventilation-perfusion imbalance on scintigraphy. Similar degrees of asymmetry and imbalance were present in 6 of the 15 children with equal-size pulmonary vessels. Asymmetry of pulmonary perfusion and ventilation-perfusion imbalance were associated with a poor prognosis

  19. A simple add-on microfluidic appliance for accurately sorting small populations of cells with high fidelity

    International Nuclear Information System (INIS)

    Current advances in single cell sequencing, gene expression and proteomics require the isolation of single cells, frequently from a very small source population. In this work we describe the design and characterization of a manually operated microfluidic cell sorter that (1) can accurately sort single or small groups of cells from very small cell populations with minimal losses, (2) that is easy to operate and that can be used in any laboratory that has a basic fluorescent microscope and syringe pump, (3) that can be assembled within minutes, (4) that can sort cells in very short time (minutes) with minimum cell stress, (5) that is cheap and reusable. This microfluidic sorter is made from hard plastic material (PMMA) into which microchannels are directly milled with hydraulic diameter of 70 µm. Inlet and outlet reservoirs are drilled through the chip. Sorting occurs through hydrodynamic switching ensuring low hydrodynamic shear stresses, which were modeled and experimentally confirmed to be below the cell damage threshold. Manually operated, the maximum sorting frequencies were approximately 10 cells min−1. Experiments verified that cell sorting operations could be achieved in as little as 15 min, including the assembly and testing of the sorter. In only one out of ten sorting experiments the sorted cells were contaminated with another cell type. This microfluidic cell sorter represents an important capability for protocols requiring fast isolation of single cells from small number of rare cell populations. (technical note)

  20. Integrated microfluidic platforms for investigating neuronal networks

    Science.gov (United States)

    Kim, Hyung Joon

    This dissertation describes the development and application of integrated microfluidics-based assay platforms to study neuronal activities in the nervous system in-vitro. The assay platforms were fabricated using soft lithography and micro/nano fabrication including microfluidics, surface patterning, and nanomaterial synthesis. The use of integrated microfluidics-based assay platform allows culturing and manipulating many types of neuronal tissues in precisely controlled microenvironment. Furthermore, they provide organized multi-cellular in-vitro model, long-term monitoring with live cell imaging, and compatibility with molecular biology techniques and electrophysiology experiment. In this dissertation, the integrated microfluidics-based assay platforms are developed for investigation of neuronal activities such as local protein synthesis, impairment of axonal transport by chemical/physical variants, growth cone path finding under chemical/physical cues, and synaptic transmission in neuronal circuit. Chapter 1 describes the motivation, objectives, and scope for developing in-vitro platform to study various neuronal activities. Chapter 2 introduces microfluidic culture platform for biochemical assay with large-scale neuronal tissues that are utilized as model system in neuroscience research. Chapter 3 focuses on the investigation of impaired axonal transport by beta-Amyloid and oxidative stress. The platform allows to control neuronal processes and to quantify mitochondrial movement in various regions of axons away from applied drugs. Chapter 4 demonstrates the development of microfluidics-based growth cone turning assay to elucidate the mechanism underlying axon guidance under soluble factors and shear flow. Using this platform, the behaviors of growth cone of mammalian neurons are verified under the gradient of inhibitory molecules and also shear flow in well-controlled manner. In Chapter 5, I combine in-vitro multicellular model with microfabricated MEA

  1. Controlling two-phase flow in microfluidic systems using electrowetting

    OpenAIRE

    Gu, Hao

    2011-01-01

    Electrowetting (EW)-based digital microfluidic systems (DMF) and droplet-based two-phase flow microfluidic systems (TPF) with closed channels are the most widely used microfluidic platforms. In general, these two approaches have been considered independently. However, integrating the two technologies into one allows to combine the advantages of both worlds: (i) high throughput (from TPF) and (ii) precise control over each individual drop (from EW). Thus the aim of this thesis was to investiga...

  2. Compilation and Synthesis for Fault-Tolerant Digital Microfluidic Biochips

    DEFF Research Database (Denmark)

    Alistar, Mirela

    Microfluidic-based biochips are replacing the conventional biochemical analyzers, by integrating all the necessary functions for biochemical analysis using microfluidics. The digital microfluidic biochips (DMBs) manipulate discrete amounts of fluids of nanoliter volume, named droplets, on an array...... of electrodes to perform operations such as dispensing, transport, mixing, split, dilution and detection. Researchers have proposed compilation approaches, which, starting from a biochemical application and a biochip architecture, determine the allocation, resource binding, scheduling, placement and routing...

  3. Redundancy Optimization for Error Recovery in Digital Microfluidic Biochips

    DEFF Research Database (Denmark)

    Alistar, Mirela; Pop, Paul; Madsen, Jan

    2015-01-01

    . Researchers have proposed approaches for the synthesis of digital microfluidic biochips, which, starting from a biochemical application and a given biochip architecture, determine the allocation, resource binding, scheduling, placement and routing of the operations in the application. During the execution......Microfluidic-based biochips are replacing the conventional biochemical analyzers, and are able to integrate all the necessary functions for biochemical analysis. The digital microfluidic biochips are based on the manipulation of liquids not as a continuous flow, but as discrete droplets...

  4. Teflon films for chemically-inert microfluidic valves and pumps

    OpenAIRE

    Grover, William H.; von Muhlen, Marcio G.; Scott R. Manalis

    2008-01-01

    We present a simple method for fabricating chemically-inert Teflon microfluidic valves and pumps in glass microfluidic devices. These structures are modeled after monolithic membrane valves and pumps that utilize a featureless polydimethylsiloxane (PDMS) membrane sandwiched between two etched glass wafers. The limited chemical compatibility of PDMS has necessitated research into alternative materials for microfluidic devices. Previous work has shown that spin-coated amorphous fluoropolymers a...

  5. Microfluidic electrocapture technology in protein and peptide analysis

    OpenAIRE

    Astorga-Wells, Juan

    2004-01-01

    After sequencing the genomes of several organisms, science in the postgenomic era now aims at a thorough study of the proteins present in a given tissue or organism. Since this task requires an enormous analytical effort, integrated microfluidic systems are envisioned as the solution to automated high throughput analysis of biomolecules. This thesis is focused on a microfluidic methodology and device that present several advantages over present technologies. The microfluidic...

  6. Ultrasonic Handling of Living Cells in Microfluidic Systems

    OpenAIRE

    Svennebring, Jessica

    2009-01-01

    Microfluidic chips have become a powerful tool in research where biological cells are processed and/or analyzed. One method for contactless cell manipulation in microfluidic chips that has gained an increasing amount of attention the last decade is ultrasonic standing wave (USW) technology. This Thesis explores the biocompatibility of USW technology applied to microfluidic chips, and presents a novel USW-based method for serial processing and accurate characterization of living cells. The bio...

  7. Design of Topologies for Interpreting Assays on Digital Microfluidic Biochips

    OpenAIRE

    Grissom, Daniel

    2014-01-01

    In the last decade, digital microfluidic biochips have emerged as a viable candidate for the automation and miniaturization of biochemistry; however, digital microfluidic designs in previous works typically suffer from two short-comings: 1.) they are unable to respond to live feedback and errors; 2.) they are application-specific, rather than programmable. In the early years of digital microfluidic research, the synthesis problems of scheduling, placement and routing were performed offline (b...

  8. Review: Microfluidic Applications in Metabolomics and Metabolic Profiling

    OpenAIRE

    Kraly, James R.; Holcomb, Ryan E.; Guan, Qian; Charles S. Henry

    2009-01-01

    Metabolomics is an emerging area of research focused on measuring small molecules in biological samples. There are a number of different types of metabolomics, ranging from global profiling of all metabolites in a single sample to measurement of a selected group of analytes. Microfluidics and related technologies have been used in this research area with good success. The aim of this review article is to summarize the use of microfluidics in metabolomics. Direct application of microfluidics t...

  9. Liposome production by microfluidics: potential and limiting factors

    OpenAIRE

    Dario Carugo; Elisabetta Bottaro; Joshua Owen; Eleanor Stride; Claudio Nastruzzi

    2016-01-01

    This paper provides an analysis of microfluidic techniques for the production of nanoscale lipid-based vesicular systems. In particular we focus on the key issues associated with the microfluidic production of liposomes. These include, but are not limited to, the role of lipid formulation, lipid concentration, residual amount of solvent, production method (including microchannel architecture), and drug loading in determining liposome characteristics. Furthermore, we propose microfluidic archi...

  10. The Potential Impact of Droplet Microfluidics in Biology

    OpenAIRE

    Schneider, Thomas; Kreutz, Jason; Chiu, Daniel T.

    2013-01-01

    Droplet microfluidics, which involves micrometer-sized emulsion droplets on a microfabricated platform, is an active research endeavor that evolved out of the larger field of microfluidics. Recently, this subfield of microfluidics has started to attract greater interest because researchers have been able to demonstrate applications of droplets as miniaturized laboratories for biological measurements. This perspective explores the recent developments and the potential future biological applica...

  11. Chemotaxis-driven assembly of endothelial barrier in a tumor-on-a-chip platform.

    Science.gov (United States)

    Aung, Aereas; Theprungsirikul, Jomkuan; Lim, Han Liang; Varghese, Shyni

    2016-05-21

    The integration of three-dimensional micropatterning with microfluidics provides a unique opportunity to create perfusable tissue constructs in vitro. Herein, we have used this approach to create a tumor-on-a-chip with an endothelial barrier. Specifically, we photopatterned a mixture of endothelial cells and cancer spheroids within a gelatin methacrylate (GelMA) hydrogel inside a microfluidic device. The differential motility of endothelial and cancer cells in response to a controlled morphogen gradient across the cell-laden network drove the migration of endothelial cells to the periphery while maintaining the cancer cells within the interior of the hydrogel. The resultant endothelial cell layer forming cell-cell contact via VE-cadherin junctions was found to encompass the entire GelMA hydrogel structure. Furthermore, we have also examined the potential of such a tumor-on-a-chip system as a drug screening platform using doxorubicin, a model cancer drug. PMID:27097908

  12. Hepatic perfusion changes in an experimental model of acute pancreatitis: Evaluation by perfusion CT

    Energy Technology Data Exchange (ETDEWEB)

    Tutcu, Semra [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Serter, Selim, E-mail: serterselim@gmail.co [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Kaya, Yavuz; Kara, Eray [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey); Nese, Nalan [Department of Pathology, Celal Bayar University, School of Medicine, Manisa (Turkey); Pekindil, Goekhan [Department of Radiology, Celal Bayar University, School of Medicine, Manisa (Turkey); Coskun, Teoman [Department of Surgery, Celal Bayar University, School of Medicine, Manisa (Turkey)

    2010-08-15

    Purpose: It is known that acute pancreatitis may cause secondary changes in several organs. Liver is one of these involved organs. In different experimental studies hepatic damages were shown histopathologically in acute pancreatitis but there are a few studies about perfusion disorders that accompany these histopathologic changes. Perfusion CT (pCT) provides the ability to detect regional and global alterations in organ blood flow. The purpose of the study was to describe hepatic perfusion changes in experimental acute pancreatitis model with pCT. Materials and methods: Forty Sprague-Dawley rats of both genders with average weights of 250 g were used. Rats were randomized into two groups. Twenty rats were in control group and 20 in acute pancreatitis group. pCT was performed. Perfusion maps were formed by processing the obtained images with perfusion CT software. Blood flow (BF) and blood volume (BV) values were obtained from these maps. All pancreatic and liver tissues were taken off with laparotomy and histopathologic investigation was performed. Student's t test was used for statistical analyses. Results: In pCT we found statistically significant increase in blood volume in both lobes of liver and in blood flow in right lobe of the liver (p < 0.01). Although blood flow in left lobe of the liver increased, it did not reach statistical significance. Conclusion: The quantitative analysis of liver parenchyma with pCT showed that acute pancreatitis causes a significant perfusion changes in the hepatic tissue. Systemic mediators seem to be effective as well as local inflammatory changes in perfusion changes.

  13. Integration of functional materials and surface modification for polymeric microfluidic systems

    International Nuclear Information System (INIS)

    The opportunity for the commercialization of microfluidic systems has surged over the recent decade, primarily for medical and the life science applications. This positive development has been spurred by an increasing number of integrated, highly functional lab-on-a-chip technologies from the research community. Toward commercialization, there is a dire need for economic manufacture which involves optimized cost for materials and structuring on the front-end as well as for a range of back-end processing steps such as surface modification, integration of functional elements, assembly and packaging. Front-end processing can readily resort to very well established polymer mass fabrication schemes, e.g. injection molding. Also assembly and packaging can often be adopted from commercially available processes. In this review, we survey the back-end processes of hybrid material integration and surface modification which often need to be tailored to the specifics of miniaturized polymeric microfluidic systems. On the one hand, the accurate control of these back-end processes proves to be the key to the technical function of the system and thus the value creation. On the other hand, the integration of functional materials constitutes a major cost factor. (topical review)

  14. Structure and fabrication details of an integrated modularized microfluidic system

    Directory of Open Access Journals (Sweden)

    Qingchang Tian

    2015-12-01

    Full Text Available This article contains schemes, original experimental data and figures for an integrated modularized microfluidic system described in “An integrated microfluidic system for bovine DNA purification and digital PCR detection [1]”. In this data article, we described the structure and fabrication of the integrated modularized microfluidic system. This microfluidic system was applied to isolate DNA from ovine tissue lysate and detect the bovine DNA with digital PCR (dPCR. The DNA extraction efficiency of the microdevice was compared with the efficiency of benchtop protocol.

  15. Microfabrication and Applications of Opto-Microfluidic Sensors

    Directory of Open Access Journals (Sweden)

    Daiying Zhang

    2011-05-01

    Full Text Available A review of research activities on opto-microfluidic sensors carried out by the research groups in Canada is presented. After a brief introduction of this exciting research field, detailed discussion is focused on different techniques for the fabrication of opto-microfluidic sensors, and various applications of these devices for bioanalysis, chemical detection, and optical measurement. Our current research on femtosecond laser microfabrication of optofluidic devices is introduced and some experimental results are elaborated. The research on opto-microfluidics provides highly sensitive opto-microfluidic sensors for practical applications with significant advantages of portability, efficiency, sensitivity, versatility, and low cost.

  16. Microfluidic-Based Robotic Sampling System for Radioactive Solutions

    Energy Technology Data Exchange (ETDEWEB)

    Jack D. Law; Julia L. Tripp; Tara E. Smith; Veronica J. Rutledge; Troy G. Garn; John Svoboda; Larry Macaluso

    2014-02-01

    A novel microfluidic based robotic sampling system has been developed for sampling and analysis of liquid solutions in nuclear processes. This system couples the use of a microfluidic sample chip with a robotic system designed to allow remote, automated sampling of process solutions in-cell and facilitates direct coupling of the microfluidic sample chip with analytical instrumentation. This system provides the capability for near real time analysis, reduces analytical waste, and minimizes the potential for personnel exposure associated with traditional sampling methods. A prototype sampling system was designed, built and tested. System testing demonstrated operability of the microfluidic based sample system and identified system modifications to optimize performance.

  17. Novel Polymer Microfluidics Technology for In Situ Planetary Exploration Project

    Data.gov (United States)

    National Aeronautics and Space Administration — Los Gatos Research proposes to develop a novel microfluidic device that combines rigid monolithic porous polymer based micro-capillary electrochromatography...

  18. General Assembly

    CERN Multimedia

    Staff Association

    2016-01-01

    5th April, 2016 – Ordinary General Assembly of the Staff Association! In the first semester of each year, the Staff Association (SA) invites its members to attend and participate in the Ordinary General Assembly (OGA). This year the OGA will be held on Tuesday, April 5th 2016 from 11:00 to 12:00 in BE Auditorium, Meyrin (6-2-024). During the Ordinary General Assembly, the activity and financial reports of the SA are presented and submitted for approval to the members. This is the occasion to get a global view on the activities of the SA, its financial management, and an opportunity to express one’s opinion, including taking part in the votes. Other points are listed on the agenda, as proposed by the Staff Council. Who can vote? Only “ordinary” members (MPE) of the SA can vote. Associated members (MPA) of the SA and/or affiliated pensioners have a right to vote on those topics that are of direct interest to them. Who can give his/her opinion? The Ordinary General Asse...

  19. Patient satisfaction with coronary CT angiography, myocardial CT perfusion, myocardial perfusion MRI, SPECT myocardial perfusion imaging and conventional coronary angiography

    Energy Technology Data Exchange (ETDEWEB)

    Feger, S.; Rief, M.; Zimmermann, E.; Richter, F.; Roehle, R. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Dewey, M. [Freie Universitaet Berlin, Department of Radiology, Charite - Universitaetsmedizin Berlin Campus Mitte, Humboldt-Universitaet zu Berlin, Berlin (Germany); Institut fuer Radiologie, Berlin (Germany); Schoenenberger, E. [Medizinische Hochschule Hannover, Department of Medicine, Hannover (Germany)

    2015-07-15

    To evaluate patient acceptance of noninvasive imaging tests for detection of coronary artery disease (CAD), including single-photon emission computed tomography myocardial perfusion imaging (SPECT-MPI), stress perfusion magnetic resonance imaging (MRI), coronary CT angiography (CTA) in combination with CT myocardial stress perfusion (CTP), and conventional coronary angiography (CCA). Intraindividual comparison of perception of 48 patients from the CORE320 multicentre multinational study who underwent rest and stress SPECT-MPI with a technetium-based tracer, combined CTA and CTP (both with contrast agent, CTP with adenosine), MRI, and CCA. The analysis was performed by using a validated questionnaire. Patients had significantly more concern prior to CCA than before CTA/CTP (p < 0.001). CTA/CTP was also rated as more comfortable than SPECT-MPI (p = 0.001). Overall satisfaction with CT was superior to that of MRI (p = 0.007). More patients preferred CT (46 %; p < 0.001) as a future diagnostic test. Regarding combined CTA/CTP, CTP was characterised by higher pain levels and an increased frequency of angina pectoris during the examination (p < 0.001). Subgroup analysis showed a higher degree of pain during SPECT-MPI with adenosine stress compared to physical exercise (p = 0.016). All noninvasive cardiac imaging tests are well accepted by patients, with CT being the preferred examination. (orig.)

  20. An easy-to-use microfluidic interconnection system to create quick and reversibly interfaced simple microfluidic devices

    DEFF Research Database (Denmark)

    Pfreundt, Andrea; Andersen, Karsten Brandt; Dimaki, Maria;

    2015-01-01

    The presented microfluidic interconnection system provides an alternative for the individual interfacing of simple microfluidic devices fabricated in polymers such as polymethylmethacrylate, polycarbonate and cyclic olefin polymer. A modification of the device inlet enables the direct attachment...... pressures above 250 psi and therefore supports applications with high flow rates or highly viscous fluids. The ease of incorporation, configuration, fabrication and use make this interconnection system ideal for the rapid prototyping of simple microfluidic devices or other integrated systems that require...

  1. Bead-Based Microfluidic Sediment Analogues: Fabrication and Colloid Transport.

    Science.gov (United States)

    Guo, Yang; Huang, Jingwei; Xiao, Feng; Yin, Xiaolong; Chun, Jaehun; Um, Wooyong; Neeves, Keith B; Wu, Ning

    2016-09-13

    Mobile colloids can act as carriers for low-solubility contaminants in the environment. However, the dominant mechanism for this colloid-facilitated transport of chemicals is unclear. Therefore, we developed a bead-based microfluidic platform of sediment analogues and measured both single and population transport of model colloids. The porous medium is assembled through a bead-by-bead injection method. This approach has the versatility to build both electrostatically homogeneous and heterogeneous media at the pore scale. A T-junction at the exit also allowed for encapsulation and enumeration of colloids effluent at single particle resolution to give population dynamics. Tortuosity calculated from pore-scale trajectory analysis and its comparison with lattice Boltzmann simulations revealed that transport of colloids was influenced by the size exclusion effect. The porous media packed by positively and negatively charged beads into two layers showed distinctive colloidal particle retention and significant remobilization and re-adsorption of particles during water flushing. We demonstrated the potential of our method to fabricate porous media with surface heterogeneities at the pore scale. With both single and population dynamics measurement, our platform has the potential to connect pore-scale and macroscale colloid transport on a lab scale and to quantify the impact of grain surface heterogeneities that are natural in the subsurface environment. PMID:27548505

  2. Microfluidic Fabrication of Pluronic Vesicles with Controlled Permeability.

    Science.gov (United States)

    do Nascimento, Débora F; Arriaga, Laura R; Eggersdorfer, Max; Ziblat, Roy; Marques, Maria de Fátima V; Reynaud, Franceline; Koehler, Stephan A; Weitz, David A

    2016-05-31

    Block copolymers with a low hydrophilic-to-lipophilic balance form membranes that are highly permeable to hydrophilic molecules. Polymersomes with this type of membrane enable the controllable release of molecules without membrane rupture. However, these polymersomes are difficult to assemble because of their low hydrophobicity. Here, we report a microfluidic approach to the production of these polymersomes using double-emulsion drops with ultrathin shells as templates. The small thickness of the middle oil phase enables the attraction of the hydrophobic blocks of the polymers adsorbed at each of the oil/water interfaces of the double emulsions; this results in the dewetting of the oil from the surface of the innermost water drops of the double emulsions and the ultimate formation of the polymersome. This approach to polymersome fabrication enables control of the vesicle size and results in the efficient encapsulation of hydrophilic ingredients that can be released through the polymer membrane without membrane rupture. We apply our approach to the fabrication of Pluronic L121 vesicles and characterize the permeability of their membranes. Furthermore, we show that membrane permeability can be tuned by blending different Pluronic polymers. Our work thus describes a route to producing Pluronic vesicles that are useful for the controlled release of hydrophilic ingredients. PMID:27192611

  3. Advances in microfluidics in combating infectious diseases.

    Science.gov (United States)

    Tay, Andy; Pavesi, Andrea; Yazdi, Saeed Rismani; Lim, Chwee Teck; Warkiani, Majid Ebrahimi

    2016-01-01

    One of the important pursuits in science and engineering research today is to develop low-cost and user-friendly technologies to improve the health of people. Over the past decade, research efforts in microfluidics have been made to develop methods that can facilitate low-cost diagnosis of infectious diseases, especially in resource-poor settings. Here, we provide an overview of the recent advances in microfluidic devices for point-of-care (POC) diagnostics for infectious diseases and emphasis is placed on malaria, sepsis and AIDS/HIV. Other infectious diseases such as SARS, tuberculosis, and dengue are also briefly discussed. These infectious diseases are chosen as they contribute the most to disability-adjusted life-years (DALYs) lost according to the World Health Organization (WHO). The current state of research in this area is evaluated and projection toward future applications and accompanying challenges are also discussed. PMID:26854743

  4. Dry-Mass Sensing for Microfluidics

    CERN Document Server

    Müller, T; Knowles, T P J

    2014-01-01

    We present an approach for interfacing an electromechanical sensor with a microfluidic device for the accurate quantification of the dry mass of analytes within microchannels. We show that depositing solutes onto the active surface of a quartz crystal microbalance by means of an on-chip microfluidic spray nozzle and subsequent solvent removal provides the basis for the real-time determination of dry solute mass. Moreover, this detection scheme does not suffer from the decrease in the sensor quality factor and the viscous drag present if the measurement is performed in a liquid environment, yet allows solutions to be analysed. We demonstrate the sensitivity and reliability of our approach by controlled deposition of nanogram levels of salt and protein from a micrometer-sized channel.

  5. Microfluidic route to generation of celloidosomes

    Science.gov (United States)

    Gundabala, Venkata; Martinez-Escobar, Sergio; Marquez, Samantha; Marquez, Manuel; Fernandez-Nieves, Alberto; Microfluidics Team

    2013-03-01

    Here we present a microfluidic method to generate alginate particles with a liquid core and a shell with yeast cells encapsulated in it. This particular class of celloidosomes with cells embedded into the thin shell region at the surface, allows for easy access of oxygen to the cells improving their viability. The liquid core opens the possibility of encapsulating multiple types of cells into the core and the shell. The microfluidic method involving double emulsion technology employed here ensures robust control over the size of the particles and density of the encapsulated cells. The study has shown that the stability of the inner core is very much dependent on the viscosity of the oil used for collecting the emulsion.

  6. Microfluidic Scintillation Detectors for High Energy Physics

    CERN Document Server

    Maoddi, Pietro; Mapelli, Alessandro

    This thesis deals with the development and study of microfluidic scintillation detectors, a technology of recent introduction for the detection of high energy particles. Most of the interest for such devices comes from the use of a liquid scintillator, which entails the possibility of changing the active material in the detector, leading to increased radiation resistance. A first part of the thesis focuses on the work performed in terms of design and modelling studies of novel prototype devices, hinting to new possibilities and applications. In this framework, the simulations performed to validate selected designs and the main technological choices made in view of their fabrication are addressed. The second part of this thesis deals with the microfabrication of several prototype devices. Two different materials were studied for the manufacturing of microfluidic scintillation detectors, namely the SU-8 photosensitive epoxy and monocrystalline silicon. For what concerns the former, an original fabrication appro...

  7. Cavity optomechanics on a microfluidic resonator

    CERN Document Server

    Kim, Kyu Hyun; Lee, Wonsuk; Liu, Jing; Tomes, Matthew; Fan, Xudong; Carmon, Tal

    2012-01-01

    Light pressure is known to excite or cool vibrations in microresonators for sensing quantum-optomechanical effects and we now show that it can be explored for investigations with liquids. Currently, optical resonances are utilized to detect analytes in liquids. However, optomechanical oscillations have never been excited when devices were immersed in liquid. This is because replacing the surrounding air with water inherently increases the acoustical impedance and the associated acoustical-radiation losses. Here we fabricate a hollow optomechanical bubble resonator with water inside, and use light pressure to excite 8 MHz - 140 MHz vibrations with 1 mW optical-threshold power and >2000 mechanical Q, constituting the first time that any microfluidic system is optomechanically actuated. Bridging between optomechanics and microfluidics will enable recently developed capillaries and on-chip bubbles to vibrate via optical excitation; and allow optomechanics with non-solid material phases including bio-analytes, sup...

  8. Electrodes for Microfluidic Integrated Optoelectronic Tweezers

    Directory of Open Access Journals (Sweden)

    Kuo-Wei Huang

    2011-01-01

    Full Text Available We report on two types of electrodes that enable the integration of optoelectronic tweezers (OETs with multilayer poly(dimethylsilane- (PDMS- based microfluidic devices. Both types of electrodes, Au-mesh and single-walled carbon nanotube- (SWNT- embedded PDMS thin film, are optically transparent, electrically conductive, and can be mechanically deformed and provide interfaces to form strong covalent bonding between an OET device and PDMS through standard oxygen plasma treatment. Au-mesh electrodes provide high electrical conductivity and high transparency but are lack of flexibility and allow only small deformation. On the other hand, SWNT-embedded PDMS thin film electrodes provide not only electrical conductivity but also optical transparency and can undergo large mechanical deformation repeatedly without failure. This enables, for the first time, microfluidic integrated OET with on-chip valve and pump functions, which is a critical step for OET-based platforms to conduct more complex and multistep biological and biochemical analyses.

  9. Microfluidic Pumping by Micromolar Salt Concentrations

    CERN Document Server

    Niu, Ran; Brown, Aidan T; Rempfer, Georg; Botin, Denis; Holm, Christian; Palberg, Thomas; de Graaf, Joost

    2016-01-01

    A colloidal ion-exchange-resin-based microfluidic pump is introduced and experimentally characterized. It operates in almost deionized water for periods exceeding 24h and effects fluid flows of um/s over hundreds of um. This fluid flow displays a far-field, power-law decay which is characteristic of two-dimensional (2D) flow when the system is strongly confined in the vertical direction, and of three-dimensional (3D) flow when the system is less confined. Using theory and numerical calculations we show that our observations are consistent with electroosmotic pumping driven by umol/L ionic impurities in the sample cell, revealing the surprising impact of trace amounts of charge carriers. In addition, we explain how the power-law decay of the fluid flow can be understood on the basis of the confinement imposed by the sample cell. These two insights should benefit the design of a new class of microfluidic pumps.

  10. Tuning fluidic resistance via liquid crystal microfluidics.

    Science.gov (United States)

    Sengupta, Anupam

    2013-01-01

    Flow of molecularly ordered fluids, like liquid crystals, is inherently coupled with the average local orientation of the molecules, or the director. The anisotropic coupling-typically absent in isotropic fluids-bestows unique functionalities to the flowing matrix. In this work, we harness this anisotropy to pattern different pathways to tunable fluidic resistance within microfluidic devices. We use a nematic liquid crystalline material flowing in microchannels to demonstrate passive and active modulation of the flow resistance. While appropriate surface anchoring conditions-which imprint distinct fluidic resistances within microchannels under similar hydrodynamic parameters-act as passive cues, an external field, e.g., temperature, is used to actively modulate the flow resistance in the microfluidic device. We apply this simple concept to fabricate basic fluidic circuits, which can be hierarchically extended to create complex resistance networks, without any additional design or morphological patterning of the microchannels. PMID:24256819

  11. Cell Culture Microfluidic Biochips: Experimental Throughput Maximization

    DEFF Research Database (Denmark)

    Minhass, Wajid Hassan; Pop, Paul; Madsen, Jan;

    2011-01-01

    Microfluidic biochips offer a promising alternative to a conventional biochemical laboratory, integrating all necessary functionalities on-chip in order to perform biochemical applications. Researchers have started to propose computer-aided design tools for the synthesis of such biochips. Our foc...... metaheuristic for experimental design generation for the cell culture microfluidic biochips, and we have evaluated our approach using multiple experimental setups....... in this paper is on the optimization of how a biochemical application is performed on a biochip. In this paper, we consider cell culture biochips, where several cell colonies are exposed to soluble compounds and monitored in real-time to determine the right combination of factors that leads to the desired...

  12. Bonding PMMA microfluidics using commercial microwave ovens

    International Nuclear Information System (INIS)

    In this paper, a novel low-cost, rapid substrate-bonding technique is successfully applied to polymethyl methacrylate (PMMA) microfluidics bonding for the first time. This technique uses a thin intermediate metallic microwave susceptor layer at the interface of the bonding site (microchannels) which produces localized heating required for bonding during microwave irradiation. The metallic susceptor pattern is designed using a multiphysics simulation model developed in ANSYS Multiphysics software (high-frequency structural simulation (HFSS) coupled with ANSYS-Thermal). In our experiments, the required microwave energy for bonding is delivered using a relatively inexpensive, widely accessible commercial microwave oven. Using this technique, simple PMMA microfluidics prototypes are successfully bonded and sealed in less than 35 seconds with a minimum measured bond strength of 1.375 MPa. (paper)

  13. Microfluidic device for unidirectional axon growth

    Science.gov (United States)

    Malishev, E.; Pimashkin, A.; Gladkov, A.; Pigareva, Y.; Bukatin, A.; Kazantsev, V.; Mukhina, I.; Dubina, M.

    2015-11-01

    In order to better understand the communication and connectivity development of neuron networks, we designed microfluidic devices with several chambers for growing dissociated neuronal cultures from mice fetal hippocampus (E18). The chambers were connected with microchannels providing unidirectional axonal growth between “Source” and “Target” neural sub-networks. Experiments were performed in a hippocampal cultures plated in a poly-dimethylsiloxane (PDMS) microfluidic chip, aligned with a 60 microelectrode array (MEA). Axonal growth through microchannels was observed with brightfield, phase-contrast and fluorescence microscopy, and after 7 days in vitro electrical activity was recorded. Visual inspection and spike propagation analysis showed the predominant axonal growth in microchannels in a direction from “Source” to “Target”.

  14. Microfluidic electroporation for cellular analysis and delivery.

    Science.gov (United States)

    Geng, Tao; Lu, Chang

    2013-10-01

    Electroporation is a simple yet powerful technique for breaching the cell membrane barrier. The applications of electroporation can be generally divided into two categories: the release of intracellular proteins, nucleic acids and other metabolites for analysis and the delivery of exogenous reagents such as genes, drugs and nanoparticles with therapeutic purposes or for cellular manipulation. In this review, we go over the basic physics associated with cell electroporation and highlight recent technological advances on microfluidic platforms for conducting electroporation. Within the context of its working mechanism, we summarize the accumulated knowledge on how the parameters of electroporation affect its performance for various tasks. We discuss various strategies and designs for conducting electroporation at the microscale and then focus on analysis of intracellular contents and delivery of exogenous agents as two major applications of the technique. Finally, an outlook for future applications of microfluidic electroporation in increasingly diverse utilities is presented.

  15. Cell-based bioassays in microfluidic systems

    Science.gov (United States)

    Itle, Laura J.; Zguris, Jeanna C.; Pishko, Michael V.

    2004-12-01

    The development of cell-based bioassays for high throughput drug screening or the sensing of biotoxins is contingent on the development of whole cell sensors for specific changes in intracellular conditions and the integration of those systems into sample delivery devices. Here we show the feasibility of using a 5-(and-6)-carboxy SNARF-1, acetoxymethyl ester, acetate, a fluorescent dye capable of responding to changes in intracellular pH, as a detection method for the bacterial endotoxin, lipopolysaccharide. We used photolithography to entrap cells with this dye within poly(ethylene) glyocol diacrylate hydrogels in microfluidic channels. After 18 hours of exposure to lipopolysaccharide, we were able to see visible changes in the fluorescent pattern. This work shows the feasibility of using whole cell based biosensors within microfluidic networks to detect cellular changes in response to exogenous agents.

  16. Microfluidic device capable of sensing ultrafast chemiluminescence.

    Science.gov (United States)

    Kim, Young-Teck; Ko, Seok Oh; Lee, Ji Hoon

    2009-05-15

    Based on the principle of liquid core waveguide, a novel microfluidic device with micro-scale detection window capable of sensing flashlight emitted from rapid 1,1'-oxalyldi-4-methylimidazole (OD4MI) chemiluminescence (CL) reaction was fabricated. Light emitted from OD4MI CL reaction occurring in the micro-dimensional pentagonal detection window (length of each line segment: 900.0 microm, depth: 50.0 microm) of the microfluidic device with two inlets and one outlet was so bright that it was possible to take an image every 1/30 s at the optimal focusing distance (60 cm) using a commercial digital camera. Peaks obtained using a flow injection analysis (FIA) system with the micro-scale detection window and OD4MI CL detection show excellent resolution and reproducibility without any band-broadening observed in analytical devices having additional reaction channel(s) to measure light generated from slow CL reaction. Maximum height (H(max)) and area (A) of peak, reproducibility and sensitivity observed in the FIA system with the microfluidic device and OD4MI CL detection depends on (1) the mole ratio between bis(2,4,6-trichlorophenyl) oxalate and 4-methyl imidazole yielding OD4MI, (2) the flow rate to mix OD4MI, H(2)O(2) and 1-AP in the detection window of the microfluidic device, and (3) H(2)O(2) concentration. We obtained linear calibration curves with wide dynamic ranges using H(max) and A. The detection limit of 1-AP determined with H(max) and A was as low as 0.05 fmole/injection (signal/background=3.0). PMID:19269463

  17. Active liquid degassing in microfluidic systems

    OpenAIRE

    Karlsson, J. Mikael; Gazin, Muriel; Laakso, Sanna; Haraldsson, Tommy; Malhotra-Kumar, Surbhi; Mäki, Minna; Goossens, Herman; van der Wijngaart, Wouter

    2013-01-01

    We present a method for efficient air bubble removal in microfluidic applications. Air bubbles are extracted from a liquid chamber into a vacuum chamber through a semipermeable membrane, consisting of PDMS coated with amorphous Teflon (R) AF 1600. Whereas air is efficiently extracted through the membrane, water loss is greatly reduced by the Teflon even at elevated temperatures. We present the water loss and permeability change with the amount of added Teflon AF to the membrane. Also, we demo...

  18. Microfluidics apparatus and methods for use thereof

    Science.gov (United States)

    Peeters, John P.; Wiggins, Thomas; Ghosh, Madhushree; Bottomley, Lawrence A.; Seminara, Salvatore; Hu, Zhiyu; Seeley, Timothy; Kossek, Sebastian

    2005-08-09

    A microfluidics device includes a plurality of interaction cells and fluid control means including i) means for providing to the interaction cells a preparation fluid, and ii) means for providing to the interaction cells a sample fluid, wherein each interaction cell receives a different sample fluid. A plurality of microcantilevers may be disposed in each of the interaction cells, wherein each of the plurality of microcantilevers configured to deflect in response to an interaction involving a component of the sample fluid.

  19. Microfluidic immunomagnetic separation for enhanced bacterial detection

    DEFF Research Database (Denmark)

    Hoyland, James; Kunstmann-Olsen, Casper; Ahmed, Shakil;

    A combined lab-on-a-chip approach combining immunomagnetic separation (IMS) and flow cytometry was developed for the enrichment and detection of salmonella contamination in food samples. Immunomagnetic beads were immobilized in chips consisting of long fractal meanders while contaminated samples ...... to obtain maximum capturing efficiency. The effects of channel volume, path length and number of bends of microfluidic chip on IMS efficiency were also determined....

  20. Fluid control structures in microfluidic devices

    Science.gov (United States)

    Mathies, Richard A.; Grover, William H.; Skelley, Alison; Lagally, Eric; Liu, Chung N.

    2008-11-04

    Methods and apparatus for implementing microfluidic analysis devices are provided. A monolithic elastomer membrane associated with an integrated pneumatic manifold allows the placement and actuation of a variety of fluid control structures, such as structures for pumping, isolating, mixing, routing, merging, splitting, preparing, and storing volumes of fluid. The fluid control structures can be used to implement a variety of sample introduction, preparation, processing, and storage techniques.

  1. Electrodes for Microfluidic Integrated Optoelectronic Tweezers

    OpenAIRE

    Kuo-Wei Huang; Sabbir Sattar; Zhong, Jiang F.; Cheng-Hsu Chou; Hsiung-Kuang Tsai; Pei-Yu Chiou

    2011-01-01

    We report on two types of electrodes that enable the integration of optoelectronic tweezers (OETs) with multilayer poly(dimethylsilane)- (PDMS-) based microfluidic devices. Both types of electrodes, Au-mesh and single-walled carbon nanotube- (SWNT-) embedded PDMS thin film, are optically transparent, electrically conductive, and can be mechanically deformed and provide interfaces to form strong covalent bonding between an OET device and PDMS through standard oxygen plasma treatment. Au-mesh ...

  2. Biofunctionalization of PDMS-based microfluidic systems

    OpenAIRE

    sprotocols

    2015-01-01

    Authors: Bergoi Ibarlucea, Cesar Fernández-Sánchez, Stefanie Demming, Stephanus Büttgenbach & Andreu Llobera ### Abstract Three simple approaches for the selective immobilization of biomolecules on the surface of poly(dimethylsiloxane) (PDMS) microfluidic systems that do not require any specific instrumentation, are described and compared. They are based in the introduction of hydroxyl groups on the PDMS surface by direct adsorption of either polyethylene glycol (PEG) or polyvinyl...

  3. Retinal synaptic regeneration via microfluidic guiding channels

    OpenAIRE

    Ping-Jung Su; Zongbin Liu; Kai Zhang; Xin Han; Yuki Saito; Xiaojun Xia; Kenji Yokoi; Haifa Shen; Lidong Qin

    2015-01-01

    In vitro culture of dissociated retinal neurons is an important model for investigating retinal synaptic regeneration (RSR) and exploring potentials in artificial retina. Here, retinal precursor cells were cultured in a microfluidic chip with multiple arrays of microchannels in order to reconstruct the retinal neuronal synapse. The cultured retinal cells were physically connected through microchannels. Activation of electric signal transduction by the cells through the microchannels was demon...

  4. Fluid control structures in microfluidic devices

    Science.gov (United States)

    Mathies, Richard A. (Inventor); Grover, William H. (Inventor); Skelley, Alison (Inventor); Lagally, Eric (Inventor); Liu, Chung N. (Inventor)

    2008-01-01

    Methods and apparatus for implementing microfluidic analysis devices are provided. A monolithic elastomer membrane associated with an integrated pneumatic manifold allows the placement and actuation of a variety of fluid control structures, such as structures for pumping, isolating, mixing, routing, merging, splitting, preparing, and storing volumes of fluid. The fluid control structures can be used to implement a variety of sample introduction, preparation, processing, and storage techniques.

  5. Optimization of microfluidic microsphere-trap arrays

    OpenAIRE

    Xu, Xiaoxiao; Sarder, Pinaki; Li, Zhenyu; Nehorai, Arye

    2013-01-01

    Microarray devices are powerful for detecting and analyzing biological targets. However, the potential of these devices may not be fully realized due to the lack of optimization of their design and implementation. In this work, we consider a microsphere-trap array device by employing microfluidic techniques and a hydrodynamic trapping mechanism. We design a novel geometric structure of the trap array in the device, and develop a comprehensive and robust framework to optimize the values of the...

  6. Multiplexed microfluidic approach for nucleic acid enrichment

    Energy Technology Data Exchange (ETDEWEB)

    VanderNoot, Victoria A.; Langevin, Stanley Alan; Bent, Zachary; Renzi, Ronald F.; Ferko, Scott M.; Van De Vreugde, James L.; Lane, Todd; Patel, Kamlesh; Branda, Steven

    2016-04-26

    A system for enhancing a nucleic acid sample may include a one pump, a denaturing chamber; a microfluidic hydroxyapatite chromatography device configured for performing hydroxyapatite chromatography on the nucleic acid sample, a sample collector, and tubing connecting the pump with the denaturing chamber, the hydroxyapatite chromatography device and the sample collector such that the pump may be used to move the nucleic acid sample from the denaturing chamber to the hydroxyapatite chromatography device and then to the sample collector.

  7. Design and Functional Testing of a Multichamber Perfusion Platform for Three-Dimensional Scaffolds

    Directory of Open Access Journals (Sweden)

    Marco Piola

    2013-01-01

    Full Text Available Perfusion culture systems are widely used in tissue engineering applications for enhancing cell culture viability in the core of three-dimensional scaffolds. In this work, we present a multichamber confined-flow perfusion system, designed to provide a straightforward platform for three-dimensional dynamic cell cultures. The device comprises 6 culture chambers allowing independent and simultaneous experiments in controlled conditions. Each chamber consists of three parts: a housing, a deformable scaffold-holder cartridge, and a 7 mL reservoir, which couples water-tightly with the housing compressing the cartridge. Short-term dynamic cell seeding experiments were carried out with MC3T3-E1 cells seeded into polycaprolactone porous scaffolds. Preliminary results revealed that the application of flow perfusion through the scaffold favored the penetration of the cells to its interior, producing a more homogeneous distribution of cells with respect to dropwise or injection seeding methods. The culture chamber layout was conceived with the aim of simplifying the user operations under laminar flow hood and minimizing the risks for contamination during handling and operation. Furthermore, a compact size, a small number of components, and the use of bayonet couplings ensured a simple, fast, and sterility-promoting assembling. Finally, preliminary in vitro tests proved the efficacy of the system in enhancing cell seeding efficiency, opening the way for further studies addressing long-term scaffold colonization.

  8. Perfusion computed tomography imaging of autoimmune pancreatitis

    International Nuclear Information System (INIS)

    Perfusion computed tomography (P-CT) is now available for the analysis of pancreatic blood flow. The aim of this study was to clarify pancreatic blood perfusion in AIP patients and the changes after steroid treatment. Color map imaging of P-CT and pancreatic time CT density curve (TDC) demonstrated that the pancreatic blood flow was attenuated in AIP patients. Pancreatic volumetric blood flow FV values of 11 AIP patients (82.7/min) were significantly lower than those of 12 normal controls (163.5/min, p=0.0006). AIP patients received steroid treatment and were re-examined, of these, 9 patients showed significantly elevated FV values after treatment (76.2/min and 109.8/min, p=0.0391, respectively). However, the changes of the values after the treatment differed in varying degrees among the individuals. P-CT is a useful method for the analysis of the blood flow in pancreatic diseases. (author)

  9. Nursing implications for Hepatic arterial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Nurses working in Nuclear Medicine assist in Hepatic Artery Catheter (HAC) perfusion studies. This scan is not widely performed in Australia, the St George hospital for example performs approximately five per year. The purpose of this article is firstly to review the indications and rationale of HAC patency studies. Secondly, this article will stress the clinical implications for the Nuclear Medicine Nurse during this study. Emphasis will be placed on the importance of patient education during the procedure. A brief overview of hepatic anatomy and the radiopharmaceuticals administered during the scan is discussed. Finally, a step by step protocol is presented to show how the perfusion/ shunt study is performed. Copyright (1999) The Australian and New Zealand Society of Nuclear Medicine Inc

  10. Non-contrast MRI perfusion angiosome in diabetic feet

    International Nuclear Information System (INIS)

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

  11. Non-contrast MRI perfusion angiosome in diabetic feet

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Jie [Cardiovascular Imaging Lab, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Hastings, Mary K.; Mueller, Michael J. [Washington University School of Medicine, The Program in Physical Therapy, St. Louis, MO (United States); Muccigross, David; Hildebolt, Charles F. [Washington University School of Medicine, Mallinckrodt Institute of Radiology, St. Louis, MO (United States); Fan, Zhaoyang [Cedars-Sinai Medical Center, Biomedical Imaging Research Institute, Los Angeles, CA (United States); Gao, Fabao [West China Hospital, Sichuan University, Department of Radiology, Chengdu (China); Curci, John [Washington University School of Medicine, The Department of Surgery, St. Louis, MO (United States)

    2015-01-15

    The purpose of this study is to develop a non-contrast magnetic resonance imaging (MRI) approach to evaluate skeletal muscle perfusion in the diabetic foot based on the concept of angiosomes of the foot. Five healthy volunteers and five participants with diabetes (HbA1c = 7.2 ± 1.8 %) without a history of peripheral artery disease were examined. The non-contrast perfusion measurements were performed during a toe flexion challenge. Absolute perfusion maps were created and two regions (medial and lateral) on the maps were segmented based on angiosomes. Regional difference in the perfusion of foot muscle was readily visualized in the MRI perfusion angiosomes during the challenge. In the participants with diabetes, the perfusion during toe flexion challenge was significantly lower than in healthy volunteers (P < 0.01). The average perfusion for the medial plantar region of the right foot was lower in subjects with diabetes (38 ± 9 ml/min/100 g) than in healthy subjects (93 ± 33 ml/min/100 g). Non-contrast MRI perfusion angiosome maps demonstrate the feasibility of determining regional perfusion in foot muscles during toe challenge and may facilitate evaluation of muscle perfusion in diabetic feet. (orig.)

  12. Dynamic CT perfusion measurement in a cardiac phantom.

    Science.gov (United States)

    Ziemer, Benjamin P; Hubbard, Logan; Lipinski, Jerry; Molloi, Sabee

    2015-10-01

    Widespread clinical implementation of dynamic CT myocardial perfusion has been hampered by its limited accuracy and high radiation dose. The purpose of this study was to evaluate the accuracy and radiation dose reduction of a dynamic CT myocardial perfusion technique based on first pass analysis (FPA). To test the FPA technique, a pulsatile pump was used to generate known perfusion rates in a range of 0.96-2.49 mL/min/g. All the known perfusion rates were determined using an ultrasonic flow probe and the known mass of the perfusion volume. FPA and maximum slope model (MSM) perfusion rates were measured using volume scans acquired from a 320-slice CT scanner, and then compared to the known perfusion rates. The measured perfusion using FPA (P(FPA)), with two volume scans, and the maximum slope model (P(MSM)) were related to known perfusion (P(K)) by P(FPA) = 0.91P(K) + 0.06 (r = 0.98) and P(MSM) = 0.25P(K) - 0.02 (r = 0.96), respectively. The standard error of estimate for the FPA technique, using two volume scans, and the MSM was 0.14 and 0.30 mL/min/g, respectively. The estimated radiation dose required for the FPA technique with two volume scans and the MSM was 2.6 and 11.7-17.5 mSv, respectively. Therefore, the FPA technique can yield accurate perfusion measurements using as few as two volume scans, corresponding to approximately a factor of four reductions in radiation dose as compared with the currently available MSM. In conclusion, the results of the study indicate that the FPA technique can make accurate dynamic CT perfusion measurements over a range of clinically relevant perfusion rates, while substantially reducing radiation dose, as compared to currently available dynamic CT perfusion techniques.

  13. Microfluidic Approaches to Bacterial Biofilm Formation

    Directory of Open Access Journals (Sweden)

    Hee-Deung Park

    2012-08-01

    Full Text Available Bacterial biofilms—aggregations of bacterial cells and extracellular polymeric substrates (EPS—are an important subject of research in the fields of biology and medical science. Under aquatic conditions, bacterial cells form biofilms as a mechanism for improving survival and dispersion. In this review, we discuss bacterial biofilm development as a structurally and dynamically complex biological system and propose microfluidic approaches for the study of bacterial biofilms. Biofilms develop through a series of steps as bacteria interact with their environment. Gene expression and environmental conditions, including surface properties, hydrodynamic conditions, quorum sensing signals, and the characteristics of the medium, can have positive or negative influences on bacterial biofilm formation. The influences of each factor and the combined effects of multiple factors may be addressed using microfluidic approaches, which provide a promising means for controlling the hydrodynamic conditions, establishing stable chemical gradients, performing measurement in a high-throughput manner, providing real-time monitoring, and providing in vivo-like in vitro culture devices. An increased understanding of biofilms derived from microfluidic approaches may be relevant to improving our understanding of the contributions of determinants to bacterial biofilm development.

  14. Wearable tactile sensor based on flexible microfluidics.

    Science.gov (United States)

    Yeo, Joo Chuan; Yu, Jiahao; Koh, Zhao Ming; Wang, Zhiping; Lim, Chwee Teck

    2016-08-16

    In this work, we develop a liquid-based thin film microfluidic tactile sensor of high flexibility, robustness and sensitivity. The microfluidic elastomeric structure comprises a pressure sensitive region and parallel arcs that interface with screen-printed electrodes. The microfluidic sensor is functionalized with a highly conductive metallic liquid, eutectic gallium indium (eGaIn). Microdeformation on the pressure sensor results in fluid displacement which corresponds to a change in electrical resistance. By emulating parallel electrical circuitry in our microchannel design, we reduced the overall electrical resistance of the sensor, therefore enhancing its device sensitivity. Correspondingly, we report a device workable within a range of 4 to 100 kPa and sensitivity of up to 0.05 kPa(-1). We further demonstrate its robustness in withstanding >2500 repeated loading and unloading cycles. Finally, as a proof of concept, we demonstrate that the sensors may be multiplexed to detect forces at multiple regions of the hand. In particular, our sensors registered unique electronic signatures in object grasping, which could provide better assessment of finger dexterity. PMID:27438370

  15. Graphene-based microfluidics for serial crystallography.

    Science.gov (United States)

    Sui, Shuo; Wang, Yuxi; Kolewe, Kristopher W; Srajer, Vukica; Henning, Robert; Schiffman, Jessica D; Dimitrakopoulos, Christos; Perry, Sarah L

    2016-08-01

    Microfluidic strategies to enable the growth and subsequent serial crystallographic analysis of micro-crystals have the potential to facilitate both structural characterization and dynamic structural studies of protein targets that have been resistant to single-crystal strategies. However, adapting microfluidic crystallization platforms for micro-crystallography requires a dramatic decrease in the overall device thickness. We report a robust strategy for the straightforward incorporation of single-layer graphene into ultra-thin microfluidic devices. This architecture allows for a total material thickness of only ∼1 μm, facilitating on-chip X-ray diffraction analysis while creating a sample environment that is stable against significant water loss over several weeks. We demonstrate excellent signal-to-noise in our X-ray diffraction measurements using a 1.5 μs polychromatic X-ray exposure, and validate our approach via on-chip structure determination using hen egg white lysozyme (HEWL) as a model system. Although this work is focused on the use of graphene for protein crystallography, we anticipate that this technology should find utility in a wide range of both X-ray and other lab on a chip applications. PMID:27241728

  16. Ultrafast velocity-mapping in microfluidic setups

    International Nuclear Information System (INIS)

    NMR in combination with designated rf coils has proven to be a powerful tool for the investigation of microfluidic setups, e.g. microreactors, micromixers and fluid drops, since it has the potential to reveal both spectroscopic, spatial and velocity information non-invasively. Despite the high spatial resolution NMR offers, the temporal resolution of NMR imaging and velocity mapping experiments in microfluidics has been low so far, because the application of ultrafast NMR velocity mapping methods to microfluidics has failed. These methods are based on multi-echo generation give rise to problems concerning magnetic field inhomogeneities (EPI), rf field inhomogeneities (PGSE-RARE) and velocity/acceleration limitations (EPI and PGSE-RARE). In this work, we exploit the advantages of the FLIESSEN (Flow Imaging Employing a Single Shot ENcoding) pulse sequence, a new ultrafast RARE-based imaging and velocity mapping method. An adjusted phase encoding strategy and a frequent update of velocity encoding during the multi-echo train makes FLIESSEN highly resilient to field inhomogeneities and velocity/acceleration effects. The performance of this technique is demonstrated on acetone flow in a microstructured phantom. Using FLIESSEN and a surface rf coil, high-fidelity 2D velocity maps were acquired within seconds.

  17. Wearable tactile sensor based on flexible microfluidics.

    Science.gov (United States)

    Yeo, Joo Chuan; Yu, Jiahao; Koh, Zhao Ming; Wang, Zhiping; Lim, Chwee Teck

    2016-08-16

    In this work, we develop a liquid-based thin film microfluidic tactile sensor of high flexibility, robustness and sensitivity. The microfluidic elastomeric structure comprises a pressure sensitive region and parallel arcs that interface with screen-printed electrodes. The microfluidic sensor is functionalized with a highly conductive metallic liquid, eutectic gallium indium (eGaIn). Microdeformation on the pressure sensor results in fluid displacement which corresponds to a change in electrical resistance. By emulating parallel electrical circuitry in our microchannel design, we reduced the overall electrical resistance of the sensor, therefore enhancing its device sensitivity. Correspondingly, we report a device workable within a range of 4 to 100 kPa and sensitivity of up to 0.05 kPa(-1). We further demonstrate its robustness in withstanding >2500 repeated loading and unloading cycles. Finally, as a proof of concept, we demonstrate that the sensors may be multiplexed to detect forces at multiple regions of the hand. In particular, our sensors registered unique electronic signatures in object grasping, which could provide better assessment of finger dexterity.

  18. Logic control of microfluidics with smart colloid

    KAUST Repository

    Wang, Limu

    2010-01-01

    We report the successful realization of a microfluidic chip with switching and corresponding inverting functionalities. The chips are identical logic control components incorporating a type of smart colloid, giant electrorheological fluid (GERF), which possesses reversible characteristics via a liquid-solid phase transition under external electric field. Two pairs of electrodes embedded on the sides of two microfluidic channels serve as signal input and output, respectively. One, located in the GERF micro-channel is used to control the flow status of GERF, while another one in the ither micro-fluidic channel is used to detect the signal generated with a passing-by droplet (defined as a signal droplet). Switching of the GERF from the suspended state (off-state) to the flowing state (on-state) or vice versa in the micro-channel is controlled by the appearance of signal droplets whenever they pass through the detection electrode. The output on-off signals can be easily demonstrated, clearly matching with GERF flow status. Our results show that such a logic switch is also a logic IF gate, while its inverter functions as a NOT gate. © The Royal Society of Chemistry 2010.

  19. A Review on Mixing in Microfluidics

    Directory of Open Access Journals (Sweden)

    Sangmo Kang

    2010-09-01

    Full Text Available Small-scale mixing is of uttermost importance in bio- and chemical analyses using micro TAS (total analysis systems or lab-on-chips. Many microfluidic applications involve chemical reactions where, most often, the fluid diffusivity is very low so that without the help of chaotic advection the reaction time can be extremely long. In this article, we will review various kinds of mixers developed for use in microfluidic devices. Our review starts by defining the terminology necessary to understand the fundamental concept of mixing and by introducing quantities for evaluating the mixing performance, such as mixing index and residence time. In particular, we will review the concept of chaotic advection and the mathematical terms, Poincare section and Lyapunov exponent. Since these concepts are developed from nonlinear dynamical systems, they should play important roles in devising microfluidic devices with enhanced mixing performance. Following, we review the various designs of mixers that are employed in applications. We will classify the designs in terms of the driving forces, including mechanical, electrical and magnetic forces, used to control fluid flow upon mixing. The advantages and disadvantages of each design will also be addressed. Finally, we will briefly touch on the expected future development regarding mixer design and related issues for the further enhancement of mixing performance.

  20. Myocardial perfusion studies in coronary diseases

    International Nuclear Information System (INIS)

    For detecting in precocious form a coronary disease is necessary to apply a diagnostic techniques. The main considerations to be indicated in the present work are: physiological considerations, myocardial perfusion studies with radiotracers such as Talio 201, 99mTc, MIBI, 99mTc-Teboroxima, 99mTc-Fosfinas, instrumentation for obtain good images,proceedings protocols, studies interpretation, standards, SPECT, anomalies standards, coronary diseases

  1. Gluconeogenesis in the perfused rat liver.

    Science.gov (United States)

    Hems, R; Ross, B D; Berry, M N; Krebs, H A

    1966-11-01

    1. A modification of the methods of Miller and of Schimassek for the perfusion of the isolated rat liver, suitable for the study of gluconeogenesis, is described. 2. The main modifications concern the operative technique (reducing the period of anoxia during the operation to 3min.) and the use of aged (non-glycolysing) red cells in the semi-synthetic perfusion medium. 3. The performance of the perfused liver was tested by measuring the rate of gluconeogenesis, of urea synthesis and the stability of adenine nucleotides. Higher rates of gluconeogenesis (1mumole/min./g.) from excess of lactate and of urea synthesis from excess of ammonia (4mumoles/min./g. in the presence of ornithine) were observed than are likely to occur in vivo where rates are limited by the rate of supply of precursor. The concentrations of the three adenine nucleotides in the liver tissue were maintained within 15% over a perfusion period of 135min. 4. Ca(2+), Na(+), K(+), Mg(2+) and phosphate were found to be required at physiological concentrations for optimum gluconeogenesis but bicarbonate and carbon dioxide could be largely replaced by phosphate buffer without affecting the rate of gluconeogenesis. 5. Maximal gluconeogenesis did not decrease maximal urea synthesis in the presence of ornithine and ammonia and vice versa. This indicates that the energy requirements were not limiting the rates of gluconeogenesis or of urea synthesis. 6. Addition of lactate, and especially ammonium salts, increased the uptake of oxygen more than expected on the basis of the ATP requirements of the gluconeogenesis and urea synthesis. PMID:5966267

  2. The evolution of perfusion education in America.

    Science.gov (United States)

    Toomasian, John M; Searles, Bruce; Kurusz, Mark

    2003-07-01

    Clinical cardiopulmonary perfusion has evolved significantly during its 50 years. The science, technology and educational processes related to cardiopulmonary bypass have undergone continual change and metamorphosis. Perfusionists were initially trained on the job or in the laboratory, but with the advent of myocardial revascularization and the explosion in cardiac surgery, the need for formal educational training programs became apparent. The American Society of Extracorporeal Technology began the arduous processes of credentialing and developing certification guidelines that have continued under the American Board of Cardiovascular Perfusion. Licensure has also been adopted in many states during the past 10 years where nearly 50% of all perfusionists are covered by some legislative act. One additonal challenge has been developing minimal standards in which perfusionists practice. The initial standards included the use of a checklist and have evolved to monitoring and recording the significant events and parameters of each clinical procedure. The education of perfusionists will continue to be a challenge related primarily to reduced fiscal resources, the applicant pool and the ever-changing demands for extracorporeal circulation services. According to demographic and census information, it is expected the overall number of cardiovascular interventions will increase dramatically towards the latter end of the current decade in the US. The question arises as to what role perfusionists will play, as treatment strategies continue to change. If the number of education programs and new graduates continue to decline, the total number of perfusionists will decline, especially as many senior perfusionists leave the field or retire. It may be difficult to predict the total number of cardiovascular interventions that will be required in the next several years. However, if the total number of cardiovascular interventions that require perfusion services increase as a function

  3. Staging of moyamoya disease by perfusion SPECT

    Energy Technology Data Exchange (ETDEWEB)

    Kuwabara, Yasuo [Kyushu Univ., Fukuoka (Japan). Hospital; Matsushima, Toshio; Fukui, Masashi

    2001-04-01

    Staging of moyamoya disease, based on angiography and PET have already been established. The authors have established staging of moyamoya disease based on perfusion SPECT, that can be summarized as follows: Stage I, no abnormality is seen at rest or after acetazolamide loading; Stage II, no abnormality is seen at rest, however, a decreased response (blood flow increase rate: <15%) is seen to acetazolamide loading (a, a decreased response is seen only in the frontal lobe; b, a decreased response is seen in regions other than the frontal lobe; and c, a decreased response is seen throughout the cerebrum); Stage III, localized decrease in blood flow (blood flow decrease compared with peripheral tissue: {>=}15%) and marked decrease in response to acetazolamide (blood flow increase rate: <5%) are seen at rest. In Stage III, CT and MRI show no abnormal findings or only mild lesions of the white matter; and Stage IV, multiple decreases in blood flow are seen at rest, and CT and MRI reveal infarctions and severe atrophy at the same sites. The above staging does not require determination of cerebral blood flow, and thus it can be used in children, in whom cerebral blood flow determination is difficult. The authors performed 99m-Tc ECD perfusion SPECT in 25 patients with moyamoya disease for the staging, and compared staging based on angiography with staging based on perfusion SPECT. The results did not show a correlation between the 2 staging methods. A problem inherent in the staging of moyamoya disease based on perfusion SPECT is that the relationship between cerebral blood flow and cerebral radioactivity concentrations may differ depending on the drug used to determine cerebral blood flow. Thus, although the present staging system does not depend on any specific radioactive drug to determine cerebral blood flow, further investigation is necessary to identify a more appropriate drug than those in current use. (K.H.)

  4. CT perfusion: principles, applications, and problems

    Science.gov (United States)

    Lee, Ting-Yim

    2004-10-01

    The fast scanning speed of current slip-ring CT scanners has enabled the development of perfusion imaging techniques with intravenous injection of contrast medium. In a typical CT perfusion study, contrast medium is injected and rapid scanning at a frequency of 1-2 Hz is used to monitor the first circulation of the injected contrast medium through a 1-2 cm thick slab of tissue. From the acquired time-series of CT images, arteries can be identified within the tissue slab to derive the arterial contrast concentration curve, Ca(t) while each individual voxel produces a tissue residue curve, Q(t) for the corresponding tissue region. Deconvolution between the measured Ca(t) and Q(t) leads to the determination of cerebral blood flow (CBF), cerebral blood volume (CBV) and mean transit time (MTT) in brain studies. In this presentation, an important application of CT perfusion in acute stroke studies - the identification of the ischemic penumbra via the CBF/CBV mismatch and factors affecting the quantitative accuracy of deconvolution, including partial volume averaging, arterial delay and dispersion are discussed.

  5. Tomographic display of ventilation-perfusion ratio

    International Nuclear Information System (INIS)

    Tomographic displays of the distribution of ventilation-perfusion ratio in six subjects with a single photon radionuclide computed tomography (RCT) were obtained. The distribution of ventilation (V) and perfusion (Q) were measured separately with continuous breathing of Kr-81m and with intravenous administration of Tc-99m labelled macroaggregates of human serum albumin (MAA). V/Q was calculated pixel-by-pixel and the distributions of V/Q were displayed in a logarithmic scale with the surrounding thoracic cage obtained from transmission CT. The number of voxel, ventilation and perfusion were plotted against log(V/Q). They had almost log normal distributions with smaller variances in healthy subjects than those with emphysema or bronchitis. In the former, much coincidence between V and Q was observed, whereas in the latter, dissociation was seen between them. This noninvasive technique provided not only the visualization of the distribution of V/Q in a transaxial images, but also the quantifications of the V-Q mismatch

  6. Ventilation-perfusion study using radioactive xenon

    International Nuclear Information System (INIS)

    In the framework of research concerning the physiopathology of the lung of aged subjects, studies were performed utilizing radioactive xenon. Subjects generally undergo three tests, two serving to evaluate ventilation. The patient is placed in a spirometric circuit containing a mixture of radioactive xenon. An initial measurement is performed after a forced inspiration preceded by a forced expiration. The second measurement is effected after the patient has respired for several minutes in the spirometer, this ensuring the equilibrium between radioactivity in the lungs and the spirometric circuit. The curves thus obtained express the distribution of gas in respiratory capacity and in total pulmonary capacity, respectively. The differences between the two curves thus represents the distribution of residual capacity. The third test, that of perfusion, is done by an intravenous injection of 133Xe in physiological solution. In normal young subjects, perfusion and ventilation are more pronounced in basal than in apical areas, but the apical-basal gradient is lower for ventilation as compared to perfusion. The spirometric examination has confirmed ventilatory alterations of old age: a slight reduction of vital capacity concerning the reduction of reserve expiratory volume; a progressive increase in residual volume and, consequently, an intrapulmonary stagnation of air; a slight increase of the time of intrapulmonary gas mixture; a slight reduction of the maximum expiratory volume per second

  7. Noncontact blood perfusion mapping in clinical applications

    Science.gov (United States)

    Iakovlev, Dmitry; Dwyer, Vincent; Hu, Sijung; Silberschmidt, Vadim

    2016-04-01

    Non-contact imaging photoplethysmography (iPPG) to detect pulsatile blood microcirculation in tissue has been selected as a successor to low spatial resolution and slow scanning blood perfusion techniques currently employed by clinicians. The proposed iPPG system employs a novel illumination source constructed of multiple high power LEDs with narrow spectral emission, which are temporally modulated and synchronised with a high performance sCMOS sensor. To ensure spectrum stability and prevent thermal wavelength drift due to junction temperature variations, each LED features a custom-designed thermal management system to effectively dissipate generated heat and auto-adjust current flow. The use of a multi-wavelength approach has resulted in simultaneous microvascular perfusion monitoring at various tissue depths, which is an added benefit for specific clinical applications. A synchronous detection algorithm to extract weak photoplethysmographic pulse-waveforms demonstrated robustness and high efficiency when applied to even small regions of 5 mm2. The experimental results showed evidences that the proposed system could achieve noticeable accuracy in blood perfusion monitoring by creating complex amplitude and phase maps for the tissue under examination.

  8. Myocardial perfusion imaging with dual energy CT.

    Science.gov (United States)

    Jin, Kwang Nam; De Cecco, Carlo N; Caruso, Damiano; Tesche, Christian; Spandorfer, Adam; Varga-Szemes, Akos; Schoepf, U Joseph

    2016-10-01

    Dual-energy CT (DECT) enables simultaneous use of two different tube voltages, thus different x-ray absorption characteristics are acquired in the same anatomic location with two different X-ray spectra. The various DECT techniques allow material decomposition and mapping of the iodine distribution within the myocardium. Static dual-energy myocardial perfusion imaging (sCTMPI) using pharmacological stress agents demonstrate myocardial ischemia by single snapshot images of myocardial iodine distribution. sCTMPI gives incremental values to coronary artery stenosis detected on coronary CT angiography (CCTA) by showing consequent reversible or fixed myocardial perfusion defects. The comprehensive acquisition of CCTA and sCTMPI offers extensive morphological and functional evaluation of coronary artery disease. Recent studies have revealed that dual-energy sCTMPI shows promising diagnostic accuracy for the detection of hemodynamically significant coronary artery disease compared to single-photon emission computed tomography, invasive coronary angiography, and cardiac MRI. The aim of this review is to present currently available DECT techniques for static myocardial perfusion imaging and recent clinical applications and ongoing investigations.

  9. Perfusion computed tomography in renal cell carcinoma

    Institute of Scientific and Technical Information of China (English)

    Chandan; J; Das; Usha; Thingujam; Ananya; Panda; Sanjay; Sharma; Arun; Kumar; Gupta

    2015-01-01

    Various imaging modalities are available for the diagnosis, staging and response evaluation of patients with renal cell carcinoma(RCC). While contrast enhanced computed tomography(CT) is used as the standard of imaging for size, morphological evaluation and response assessment in RCC, a new functional imaging technique like perfusion CT(p CT), goes down to the molecular level and provides new perspectives in imaging of RCC. p CT depicts regional tumor perfusion and vascular permeability which are indirect parameters of tumor angiogenesis and thereby provides vital information regarding tumor microenvironment. Also response evaluation using p CT may predate the size criteria used in Response Evaluation Criteria in Solid Tumors, as changes in the perfusion occurs earlier following tissue kinase inhibitors before any actual change in size. This may potentially help in predicting prognosis, better selection of therapy and more accurate and better response evaluation in patients with RCC. This article describes the techniques and role of p CT in staging and response assessment in patients with RCCs.

  10. Inhomogeneity of pulmonary perfusion during sustained microgravity

    Science.gov (United States)

    Prisk, G. Kim; Guy, Harold J. B.; Elliott, Ann R.; West, John B.

    1994-01-01

    The effects of gravity on the inhomogeneity of pulmonary perfusion in man were studied by performing hyperventilation-breathhold single-breath measurements before, during and after 9 days of continuous exposure to microgravity. In microgravity the indicators of inhomogeneity of perfusion, especially the size of cardiogenic oscillations in expired CO2 and the height of phase 4, were both markedly reduced. Cardiogenic oscillations were reduced to approximately 60 of their preflight standing size, while the height of phase 4 was between 0 and -8% (a terminal fall became a small terminal rise) of preflights standing. The terminal change in CO2 was nearly abolished in microgravity indicating more uniformity of blood flow between lung units that close at the end of expiration and units that remain open. This may result from the disappearance of gravity-dependent topographical inequality of blood flow. The residual cardiographic oscillations in expired CO2 imply a persisting inhomogeneity of perfusion in the absence of gravity at a level larger than acinar.

  11. Pulsatile microfluidics as an analytical tool for determining the dynamic characteristics of microfluidic systems

    DEFF Research Database (Denmark)

    Vedel, Søren; Olesen, Laurits Højgaard; Bruus, Henrik

    2010-01-01

    An understanding of all fluid dynamic time scales is needed to fully understand and hence exploit the capabilities of fluid flow in microfluidic systems. We propose the use of harmonically oscillating microfluidics as an analytical tool for the deduction of these time scales. Furthermore, we...... suggest the use of system-level equivalent circuit theory as an adequate theory of the behavior of the system. A novel pressure source capable of operation in the desired frequency range is presented for this generic analysis. As a proof of concept, we study the fairly complex system of water...

  12. Assembling consumption

    DEFF Research Database (Denmark)

    Assembling Consumption marks a definitive step in the institutionalisation of qualitative business research. By gathering leading scholars and educators who study markets, marketing and consumption through the lenses of philosophy, sociology and anthropology, this book clarifies and applies...... the investigative tools offered by assemblage theory, actor-network theory and non-representational theory. Clear theoretical explanation and methodological innovation, alongside empirical applications of these emerging frameworks will offer readers new and refreshing perspectives on consumer culture and market...... societies. This is an essential reading for both seasoned scholars and advanced students of markets, economies and social forms of consumption....

  13. Heater assembly

    International Nuclear Information System (INIS)

    An electrical resistance heater, installed in the H1 borehole, is used to thermally perturb the rock mass through a controlled heating and cooling cycle. Heater power levels are controlled by a Variac power transformer and are measured by wattmeters. Temperatures are measured by thermocouples on the borehole wall and on the heater assembly. Power and temperature values are recorded by the DAS described in Chapter 12. The heater assembly consists of a 3.55-m (11.6-ft) long by 20.3-cm (8-in.) O.D., Type 304 stainless steel pipe, containing a tubular hairpin heating element. The element has a heated length of 3 m (9.84 ft). The power rating of the element is 10 kW; however, we plan to operate the unit at a maximum power of only 3 kW. The heater is positioned with its midpoint directly below the axis of the P2 borehole, as shown in the borehole configuration diagram. This heater midpoint position corresponds to a distance of approximately 8.5 m (27.9 ft) from the H1 borehole collar. A schematic of the heater assembly in the borehole is shown. The distance from the borehole collar to the closest point on the assembly (the front end) is 6.5 m (21.3 ft). A high-temperature inflatable packer, used to seal the borehole for moisture collection, is positioned 50 cm (19.7 in.) ahead of the heater front end. The heater is supported and centralized within the borehole by two skids, fabricated from 25-mm (1-in.) O.D. stainless steel pipe. Thermocouples are installed at a number of locations in the H1 borehole. Four thermocouples that are attached to the heater skin monitor temperatures on the outer surface of the can, while three thermocouples that are held in place by rock sections monitor borehole wall temperatures beneath the heater. Temperatures are also monitored at the heater terminal and on the packer hardware

  14. Hepatic arterial perfusion increases in the early stage of severe acute pancreatitis patients: Evaluation by perfusion computed tomography

    International Nuclear Information System (INIS)

    Purpose: Although hepatic perfusion abnormalities have been reported in patients with acute pancreatitis, hepatic perfusion with severe acute pancreatitis (SAP) has not been quantitatively evaluated in humans. Therefore, we investigated hepatic perfusion in patients with SAP using perfusion CT. Materials and methods: Hepatic perfusion CT was performed in 67 patients with SAP within 3 days after symptom onset. The patients were diagnosed as having SAP according to the Atlanta criteria. Fifteen cases were established as a control group. Perfusion CT was obtained for 54 s beginning with a bolus injection of 40 ml of contrast agent (600–630 mgI/kg) at a flow rate of 4 ml/s. Perfusion data were analyzed by the dual-input maximum slope method to obtain hepatic arterial perfusion (HAP) and hepatic portal perfusion (HPP). Finally, we compared HAP and HPP in SAP patients with those in the control group, respectively. Results: Average HAP was significantly higher in SAP patients than in the control group (75.1 ± 38.0 vs. 38.2 ± 9.0 ml/min/100 ml; p < 0.001). There was no significant difference in average HPP between SAP patients and the control group (206.7 ± 54.9 vs. 204.4 ± 38.5 ml/min/100 ml; p = 0.92). Conclusion: Using quantitative analysis on perfusion CT, we first demonstrated an increase of HAP in the right hepatic lobe in SAP patients.

  15. A direct comparison of the sensitivity of CT and MR cardiac perfusion using a myocardial perfusion phantom

    Science.gov (United States)

    Otton, James; Morton, Geraint; Schuster, Andreas; Bigalke, Boris; Marano, Riccardo; Olivotti, Luca; Nagel, Eike; Chiribiri, Amedeo

    2013-01-01

    Background Direct comparison of CT and magnetic resonance (MR) perfusion techniques has been limited and in vivo assessment is affected by physiological variability, timing of image acquisition, and parameter selection. Objective We precisely compared high-resolution k-t SENSE MR cardiac perfusion at 3 T with single-phase CT perfusion (CTP) under identical imaging conditions. Methods We used a customized MR imaging and CT compatible dynamic myocardial perfusion phantom to represent the human circulation. CT perfusion studies were performed with a Philips iCT (256 slice) CT, with isotropic resolution of 0.6 mm3. MR perfusion was performed with k-t SENSE acceleration at 3 T and spatial resolution of 1.2 × 1.2 × 10 mm. The image contrast between normal and underperfused myocardial compartments was quantified at various perfusion and photon energy settings. Noise estimates were based on published clinical data. Results Contrast by CTP highly depends on photon energy and also timing of imaging within the myocardial perfusion upslope. For an identical myocardial perfusion deficit, the native image contrast-to-noise ratio (CNR) generated by CT and MR are similar. If slice averaging is used, the CNR of a perfusion deficit is expected to be greater for CTP than MR perfusion (MRP). Perfect timing during single time point CTP imaging is difficult to achieve, and CNR by CT decreases by 24%–31% two seconds from the optimal imaging time point. Although single-phase CT perfusion offers higher spatial resolution, MRP allows multiple time point sampling and quantitative analysis. Conclusion The ability of CTP and current optimal MRP techniques to detect simulated myocardial perfusion deficits is similar. PMID:23622506

  16. Digital perfusion images for estimating redistribution of pulmonary perfusion in patients with congestive heart failure

    International Nuclear Information System (INIS)

    For estimating redistribution of pulmonary perfusion in congestive heart failure (CHF), Tc-99m MAA pulmonary perfusion images were computerized to digital perfusion images (DPLs), and 100%-70% discount area was defined as hyperperfusion area (H). Various types of DPI were obtained from patients with various degree of CHF; however, they were simply classified into six types according to patterns of H, that is, from basal triangle to apical circle. DPIs changed according to aggravation and improvement of CHF. Patients without H in the lower zone suffered from refractory CHF, and their 2-year mortality was high (59%; 13 of 22). DPIs were useful for determining therapeutic policy and estimating prognosis of patients with CHF

  17. Transport of benzo[alpha]pyrene in the dually perfused human placenta perfusion model: effect of albumin in the perfusion medium

    DEFF Research Database (Denmark)

    Mathiesen, Line; Rytting, Erik; Mose, Tina;

    2009-01-01

    Transport of benzo[alpha]pyrene (BaP) across the placenta was examined because it is a ubiquitous and highly carcinogenic substance found in tobacco smoke, polluted air and certain foods. Foetal exposure to this substance is highly relevant but is difficult to estimate. The human placenta is unique...... compared to other species; since it is available without major ethical obstacles, we have used the human placenta perfusion model to study transport from mother to foetus. Placentas were donated after births at Rigshospitalet in Copenhagen from pregnant mothers who signed an informed consent. Ba......P is lipophilic and studies using cell culture medium in 6-hr placenta perfusions showed minimal transport through the placenta. To increase the solubility of BaP in perfusion medium and to increase physiological relevance, perfusions were also performed with albumin added to the perfusion medium [2 and 30 mg...

  18. Fabrication and characterization of gels with integrated channels using 3D printing with microfluidic nozzle for tissue engineering applications.

    Science.gov (United States)

    Attalla, R; Ling, C; Selvaganapathy, P

    2016-02-01

    The lack of a simple and effective method to integrate vascular network with engineered scaffolds and tissue constructs remains one of the biggest challenges in true 3D tissue engineering. Here, we detail the use of a commercially available, low-cost, open-source 3D printer modified with a microfluidic print-head in order to develop a method for the generation of instantly perfusable vascular network integrated with gel scaffolds seeded with cells. The print-head features an integrated coaxial nozzle that allows the fabrication of hollow, calcium-polymerized alginate tubes that can be easily patterned using 3D printing techniques. The diameter of the hollow channel can be precisely controlled and varied between 500 μm - 2 mm by changing applied flow rates or print-head speed. These channels are integrated into gel layers with a thickness of 800 μm - 2.5 mm. The structural rigidity of these constructs allows the fabrication of multi-layered structures without causing the collapse of hollow channels in lower layers. The 3D printing method was fully characterized at a range of operating speeds (0-40 m/min) and corresponding flow rates (1-30 mL/min) were identified to produce precise definition. This microfluidic design also allows the incorporation of a wide range of scaffold materials as well as biological constituents such as cells, growth factors, and ECM material. Media perfusion of the channels causes a significant viability increase in the bulk of cell-laden structures over the long-term. With this setup, gel constructs with embedded arrays of hollow channels can be created and used as a potential substitute for blood vessel networks. PMID:26842949

  19. Fabrication and characterization of gels with integrated channels using 3D printing with microfluidic nozzle for tissue engineering applications.

    Science.gov (United States)

    Attalla, R; Ling, C; Selvaganapathy, P

    2016-02-01

    The lack of a simple and effective method to integrate vascular network with engineered scaffolds and tissue constructs remains one of the biggest challenges in true 3D tissue engineering. Here, we detail the use of a commercially available, low-cost, open-source 3D printer modified with a microfluidic print-head in order to develop a method for the generation of instantly perfusable vascular network integrated with gel scaffolds seeded with cells. The print-head features an integrated coaxial nozzle that allows the fabrication of hollow, calcium-polymerized alginate tubes that can be easily patterned using 3D printing techniques. The diameter of the hollow channel can be precisely controlled and varied between 500 μm - 2 mm by changing applied flow rates or print-head speed. These channels are integrated into gel layers with a thickness of 800 μm - 2.5 mm. The structural rigidity of these constructs allows the fabrication of multi-layered structures without causing the collapse of hollow channels in lower layers. The 3D printing method was fully characterized at a range of operating speeds (0-40 m/min) and corresponding flow rates (1-30 mL/min) were identified to produce precise definition. This microfluidic design also allows the incorporation of a wide range of scaffold materials as well as biological constituents such as cells, growth factors, and ECM material. Media perfusion of the channels causes a significant viability increase in the bulk of cell-laden structures over the long-term. With this setup, gel constructs with embedded arrays of hollow channels can be created and used as a potential substitute for blood vessel networks.

  20. Universal lab-on-a-chip platform for complex, perfused 3D cell cultures

    Science.gov (United States)

    Sonntag, F.; Schmieder, F.; Ströbel, J.; Grünzner, S.; Busek, M.; Günther, K.; Steege, T.; Polk, C.; Klotzbach, U.

    2016-03-01

    The miniaturization, rapid prototyping and automation of lab-on-a-chip technology play nowadays a very important role. Lab-on-a-chip technology is successfully implemented not only for environmental analysis and medical diagnostics, but also as replacement of animals used for the testing of substances in the pharmaceutical and cosmetics industries. For that purpose the Fraunhofer IWS and partners developed a lab-on-a-chip platform for perfused cell-based assays in the last years, which includes different micropumps, valves, channels, reservoirs and customized cell culture modules. This technology is already implemented for the characterization of different human cell cultures and organoids, like skin, liver, endothelium, hair follicle and nephron. The advanced universal lab-on-a-chip platform for complex, perfused 3D cell cultures is divided into a multilayer basic chip with integrated micropump and application-specific 3D printed cell culture modules. Moreover a technology for surface modification of the printed cell culture modules by laser micro structuring and a complex and flexibly programmable controlling device based on an embedded Linux system was developed. A universal lab-on-a-chip platform with an optional oxygenator and a cell culture module for cubic scaffolds as well as first cell culture experiments within the cell culture device will be presented. The module is designed for direct interaction with robotic dispenser systems. This offers the opportunity to combine direct organ printing of cells and scaffolds with the microfluidic cell culture module. The characterization of the developed system was done by means of Micro-Particle Image Velocimetry (μPIV) and an optical oxygen measuring system.

  1. Reversible ventilation and perfusion abnormalities in unilateral obstructed lung

    International Nuclear Information System (INIS)

    An intraluminal carcinoid tumor obstructing the left mainstem bronchus produced hypoxemia through alteration in ventilation/perfusion matching. Studies of regional lung function using 133-xenon (/sup 133/Xe) and a multiprobe computerized instrumentation system documented a reduction of perfusion to 22 percent and ventilation to 6 percent of the total. There was negligible washout of intravenously injected /sup 133/Xe from the left lung consistent with air trapping. Four days after left mainstem bronchial sleeve resection, perfusion, ventilation and washout of injected xenon had significantly improved and by four months postresection, all measurements were virtually normal, although complete restoration of perfusion in relation to ventilation was delayed. Regional lung function studied with a multiprobe system in this patient provided a clinical model for the study of ventilation and perfusion inter-relationships in large airway obstruction and demonstrated that a prolonged time may be required for return of perfusion to normal

  2. Quantitative analysis of SPECT imaging parameters in patients with resting perfusion defects on myocardial perfusion scintigraphy

    International Nuclear Information System (INIS)

    Functional status/contractile behaviour of hibernating myocardium was analyzed objectively by analyzing the available quantitative parameters obtained on gated SPECT myocardial perfusion imaging (MPI) using Emory cardiac toolbox (ECTB) software. Materials and Methods: In this retrospective study, 70 patients with perfusion defects on 99Tc-Sestamibi MPI (12 females, 58 males) who also underwent 18F-FDG Cardiac PET study for assessment of hibernating myocardium were included for analysis. Patients were divided in three categories based on summed rest score (SRS) obtained from ECTB software, depicting the extent of perfusion defects. In a study population matched for extent of perfusion defects, quantitative parameters obtained from ECTB software such as left ventricular ejection fraction (LVEF), left ventricular end diastolic volume (EDV), left ventricular end systolic volume (ESV) and left ventricular stroke volume (SV) were compared between patients showing evidence of hibernating myocardium and patients showing no evidence of hibernating myocardium. Student 't' test was applied on the given observations and a P-value <0.05 was considered as a significant difference between the means in two categories. Results: There was no significant difference in LVEF, EDV, ESV and SV measurements between those who demonstrate hibernating myocardium and those who show no evidence of hibernating myocardium across all the categories of patients. Few trends were evident in the present study in LVEF, EDV and ESV measurements i.e., fall in mean LVEF with increasing SRS and rise in mean EDV and ESV with increasing SRS. Conclusions: The findings were consistent with the nature of hibernating myocardium i.e., non-contractile and dysfunctional. The fall in the LVEF was suggestive of deteriorating myocardial function with increasing extent of perfusion defects. The increasing left ventricular EDV and ESV with increasing extent of perfusion defects was suggestive of rising incidence of

  3. Embossed Teflon AF Laminate Membrane Microfluidic Diaphragm Valves

    Science.gov (United States)

    Willis, Peter; Hunt, Brian; White,Victor; Grunthaner, Frank

    2008-01-01

    A microfluidic system has been designed to survive spaceflight and to function autonomously on the Martian surface. It manipulates microscopic quantities of liquid water and performs chemical analyses on these samples to assay for the presence of molecules associated with past or present living processes. This technology lies at the core of the Urey Instrument, which is scheduled for inclusion on the Pasteur Payload of the ESA ExoMars rover mission in 2013. Fabrication processes have been developed to make the microfabricated Teflon-AF microfluidic diaphragm pumps capable of surviving extreme temperature excursions before and after exposure to liquid water. Two glass wafers are etched with features and a continuous Teflon membrane is sandwiched between them (see figure). Single valves are constructed using this geometry. The microfabricated devices are then post processed by heating the assembled device while applying pneumatic pressure to force the Teflon diaphragm against the valve seat while it is softened. After cooling the device, the embossed membrane retains this new shape. This solves previous problems with bubble introduction into the fluid flow where deformations of the membrane at the valve seat occurred during device bonding at elevated temperatures (100-150 C). The use of laminated membranes containing commercial Teflon AF 2400 sheet sandwiched between spun Teflon AF 1600 layers performed best, and were less gas permeable than Teflon AF 1600 membranes on their own. Spinning Teflon AF 1600 solution (6 percent in FLOURINERT(Registered TradeMark) FC40 solvent, 3M Company) at 500 rpm for 1.5 seconds, followed by 1,000 rpm for 3 seconds onto Borofloat glass wafers, results in a 10-micron-thick film of extremely smooth Teflon AF. This spinning process is repeated several times on flat, blank, glass wafers in order to gradually build a thick, smooth membrane. After running this process at least five times, the wafer and Teflon coating are heated under vacuum

  4. General Assembly

    CERN Multimedia

    Staff Association

    2015-01-01

    Mardi 5 mai à 11 h 00 Salle 13-2-005 Conformément aux statuts de l’Association du personnel, une Assemblée générale ordinaire est organisée une fois par année (article IV.2.1). Projet d’ordre du jour : 1- Adoption de l’ordre du jour. 2- Approbation du procès-verbal de l’Assemblée générale ordinaire du 22 mai 2014. 3- Présentation et approbation du rapport d’activités 2014. 4- Présentation et approbation du rapport financier 2014. 5- Présentation et approbation du rapport des vérificateurs aux comptes pour 2014. 6- Programme 2015. 7- Présentation et approbation du projet de budget 2015 et taux de cotisation pour 2015. 8- Pas de modifications aux Statuts de l'Association du personnel proposée. 9- Élections des membres de la Commission é...

  5. General assembly

    CERN Multimedia

    Staff Association

    2015-01-01

    Mardi 5 mai à 11 h 00 Salle 13-2-005 Conformément aux statuts de l’Association du personnel, une Assemblée générale ordinaire est organisée une fois par année (article IV.2.1). Projet d’ordre du jour : Adoption de l’ordre du jour. Approbation du procès-verbal de l’Assemblée générale ordinaire du 22 mai 2014. Présentation et approbation du rapport d’activités 2014. Présentation et approbation du rapport financier 2014. Présentation et approbation du rapport des vérificateurs aux comptes pour 2014. Programme 2015. Présentation et approbation du projet de budget 2015 et taux de cotisation pour 2015. Pas de modifications aux Statuts de l'Association du personnel proposée. Élections des membres de la Commission électorale. &am...

  6. General Assembly

    CERN Multimedia

    Staff Association

    2016-01-01

    Mardi 5 avril à 11 h 00 BE Auditorium Meyrin (6-2-024) Conformément aux statuts de l’Association du personnel, une Assemblée générale ordinaire est organisée une fois par année (article IV.2.1). Projet d’ordre du jour : Adoption de l’ordre du jour. Approbation du procès-verbal de l’Assemblée générale ordinaire du 5 mai 2015. Présentation et approbation du rapport d’activités 2015. Présentation et approbation du rapport financier 2015. Présentation et approbation du rapport des vérificateurs aux comptes pour 2015. Programme de travail 2016. Présentation et approbation du projet de budget 2016 Approbation du taux de cotisation pour 2017. Modifications aux Statuts de l'Association du personnel proposée. Élections des membres de la Commissio...

  7. Immuno-capture and in situ detection of Salmonella typhimurium on a novel microfluidic chip

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Renjie, E-mail: 1058464972@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Ni, Yanan, E-mail: 468885029@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Xu, Yi, E-mail: xuyibbd@sina.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); National Center for International Research of Micro/Nano-System and New Material Technology, No. 174, St. Shazhengjie, Shapingba District, Chongqing (China); Key Laboratory of Fundamental Science of Micro/Nano-Device and System Technology for National Defense, Chongqing (China); Jiang, Yan, E-mail: 919865356@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Dong, Chunyan, E-mail: 774176325@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China); Chuan, Na, E-mail: 814859441@qq.com [College of Chemistry and Chemical Engineering, Chongqing University, No. 174, St. Shazheng, Shapingba District, Chongqing (China)

    2015-01-01

    Highlights: • A novel microfluidic chip and a LIF microsystem were designed and fabricated. • Salmonella typhimurium was captured and labeled by specific immuno-capture on chip. • CdSe/ZnS quantum dots-labeled bacteria were detected by in situ analysis using LIF microsystem. • The proposed method has potential application in practice. - Abstract: The new method presented in this article achieved the goal of capturing Salmonella typhimurium via immunoreaction and rapid in situ detection of the CdSe/ZnS quantum dots (QDs) labeled S. typhimurium by self-assembly light-emitting diode-induced fluorescence detection (LIF) microsystem on a specially designed multichannel microfluidic chip. CdSe/ZnS QDs were used as fluorescent markers improving detection sensitivity. The microfluidic chip developed in this study was composed of 12 sample channels, 3 mixing zones, and 6 immune reaction zones, which also acted as fluorescence detection zones. QDs–IgG–primary antibody complexes were generated by mixing CdSe/ZnS QDs conjugated secondary antibody (QDs–IgG) and S. typhimurium antibody (primary antibody) in mixing zones. Then, the complexes went into immune reaction zones to label previously captured S. typhimurium in the sandwich mode. The capture rate of S. typhimurium in each detection zone was up to 70%. The enriched QDs-labeled S. typhimurium was detected using a self-assembly LIF microsystem. A good linear relationship was obtained in the range from 3.7 × 10 to 3.7 × 10{sup 5} cfu mL{sup −1} using the equation I = 0.1739 log (C) − 0.1889 with R{sup 2} = 0.9907, and the detection limit was down to 37 cfu mL{sup −1}. The proposed method of online immunolabeling with QDs for in situ fluorescence detection on the designed multichannel microfluidic chip had been successfully used to detect S. typhimurium in pork sample, and it has shown potential advantages in practice.

  8. A microfluidic AFM cantilever based dispensing and aspiration platform

    NARCIS (Netherlands)

    Van Oorschot, R.; Perez Garza, H.H.; Derks, R.J.S.; Staufer, U.; Ghatkesar, M.K.

    2015-01-01

    We present the development of a microfluidic AFM (atomic force microscope) cantilever-based platform to enable the local dispensing and aspiration of liquid with volumes in the pico-to-femtoliter range. The platform consists of a basic AFM measurement system, microfluidic AFM chip, fluidic interface

  9. Optical manipulation with two beam traps in microfluidic polymer systems

    DEFF Research Database (Denmark)

    Khoury Arvelo, Maria; Matteucci, Marco; Sørensen, Kristian Tølbøl;

    2015-01-01

    An optical trapping system with two opposing laser beams, also known as the optical stretcher, are naturally constructed inside a microfluidic lab-on-chip system. We present and compare two approaches to combine a simple microfluidic system with either waveguides directly written in the microflui...

  10. Microfluidics and Microfabrication in a Chemical Engineering Lab

    Science.gov (United States)

    Archer, Shivaun D.

    2011-01-01

    Microfluidics, the manipulation of fluids in channels with micron dimensions, has emerged as an exciting new field that impacts the broad area of nano/microtechnology. This is an important area to train the next generation of chemical engineers. This paper describes an experiment where students are given a problem to design a microfluidic mixer…

  11. A microfluidic device based on an evaporation-driven micropump

    NARCIS (Netherlands)

    Nie, C.; Frijns, A.J.H.; Mandamparambil, R.; Toonder, J.M.J. den

    2015-01-01

    In this paper we introduce a microfluidic device ultimately to be applied as a wearable sweat sensor. We show proof-of-principle of the microfluidic functions of the device, namely fluid collection and continuous fluid flow pumping. A filter-paper based layer, that eventually will form the interface

  12. Flow control in microfluidic chips : Material choice and smart design

    NARCIS (Netherlands)

    Debrauwer, P.; Emmelkamp, J.; Bolt, P.J.

    2009-01-01

    This paper describes a model and experiments to validate it for the design of bubble free chambers and channels in microfluidic chips. When handling liquids in a microfluidic chip problems may arise with entrapping air or liquid. These air and liquid bubbles deteriorate the efficiency of the process

  13. High-throughput injection with microfluidics using picoinjectors

    OpenAIRE

    Abate, Adam R.; Hung, Tony; Mary, Pascaline; Agresti, Jeremy J.; Weitz, David A.

    2010-01-01

    Adding reagents to drops is one of the most important functions in droplet-based microfluidic systems; however, a robust technique to accomplish this does not exist. Here, we introduce the picoinjector, a robust device to add controlled volumes of reagent using electro-microfluidics at kilohertz rates. It can also perform multiple injections for serial and combinatorial additions.

  14. Formation and Transport of Bubbles in Microfluidic Systems

    NARCIS (Netherlands)

    Van Steijn, V.

    2010-01-01

    Precise manipulation of minute volumes of fluids is at the heart of microfluidics and opens up an exciting route to miniaturize processes in the areas of chemistry, biology and medicine. An attractive way to transport small fluid samples through the channels of microfluidic devices is by enclosing t

  15. The low specificity of postoperative perfusion lung scan defects.

    OpenAIRE

    I Walker; Aukland, P; Hirsh, J.; Coates, G.; Cockshott, P; Taylor, R; Hull, R.

    1981-01-01

    Ventilation and perfusion lung scans were performed preoperatively and postoperatively in 169 patients and classified blindly according to preset criteria. Perfusion lung scan abnormalities were present in 25 (15%) of the preoperative scans and 42 (25%) of the postoperative scans; 16 (38%) of the 42 abnormal postoperative scans were identical to the preoperative scans. Perfusion defects indicating a "high probability" of pulmonary embolism (lobar or segmental defects) were present in 5 preope...

  16. Whole-brain dynamic CT angiography and perfusion imaging

    Energy Technology Data Exchange (ETDEWEB)

    Orrison, W.W. [CHW Nevada Imaging Company, Nevada Imaging Centers, Spring Valley, Las Vegas, NV (United States); College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Department of Medical Education, University of Nevada School of Medicine, Reno, NV (United States); Snyder, K.V.; Hopkins, L.N. [Department of Neurosurgery, Millard Fillmore Gates Circle Hospital, Buffalo, NY (United States); Roach, C.J. [School of Life Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States); Ringdahl, E.N. [Department of Psychology, University of Nevada Las Vegas, Las Vegas, NV (United States); Nazir, R. [Shifa International Hospital, Islamabad (Pakistan); Hanson, E.H., E-mail: eric.hanson@amigenics.co [College of Osteopathic Medicine, Touro University Nevada, Henderson, NV (United States); Department of Health Physics and Diagnostic Sciences, University of Nevada Las Vegas, Las Vegas, NV (United States); Advanced Medical Imaging and Genetics (Amigenics), Las Vegas, NV (United States)

    2011-06-15

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

  17. Whole-brain dynamic CT angiography and perfusion imaging

    International Nuclear Information System (INIS)

    The availability of whole brain computed tomography (CT) perfusion has expanded the opportunities for analysing the haemodynamic parameters associated with varied neurological conditions. Examples demonstrating the clinical utility of whole-brain CT perfusion imaging in selected acute and chronic ischaemic arterial neurovascular conditions are presented. Whole-brain CT perfusion enables the detection and focused haemodynamic analyses of acute and chronic arterial conditions in the central nervous system without the limitation of partial anatomical coverage of the brain.

  18. Feasibility of perfusion cardiovascular magnetic resonance in paediatric patients

    OpenAIRE

    Kellenberger Christian; Schwitter Juerg; Buechel Emanuela; Balmer Christian; Bauersfeld Urs

    2009-01-01

    Abstract Aims As coronary artery disease may also occur during childhood in some specific conditions, we sought to assess the feasibility and accuracy of perfusion cardiovascular magnetic resonance (CMR) in paediatric patients. Methods and results First-pass perfusion CMR studies were performed under pharmacological stress with adenosine and by using a hybrid echo-planar pulse sequence with slice-selective saturation recovery preparation. Fifty-six perfusion CMR examinations were performed in...

  19. Combined ventilation-perfusion scintigraphy for demonstration of pulmonary embolism

    International Nuclear Information System (INIS)

    In 34 patients with suggested pulmonary emboli, ventilation scintigraphy with 133Xe and perfusion scintigraphy with 99Tcsup(m)-labelled albumin spheres were carried out. The combined ventilation-perfusion scintigraphy had a significantly higher diagnostic specificity (1.0, confidence limit 0.69-1.0) than perfusion scintigraphy alone (0.48, 0.26-0.70). Both methods had a diagnostic sensitivity of 1.0. (Auth.)

  20. Scintigraphic control of blood vessels in regional perfusion with cytostatics

    Energy Technology Data Exchange (ETDEWEB)

    Blazek, J.; Broz, J. (Krajska Nemocnice s Poliklinikou, Ceske Budejovice (Czechoslovakia))

    1982-12-01

    After administration of sup(99m)Tc-MAA or sup(113m)In-MAA into the perfusion system during regional perfusion therapy with cytostatics of malignomas in the maxillo-facial area it is possible to obtain by subsequent scintigraphic visualization of the distribution of radioactivity an accurate topographic picture of the perfusion in the appropriate area. The method is free from complications and there are no contraindications. The paper is supplemented by scintigrams.