Showing papers on "Fluidics published in 2010"

Reversibly deformable and mechanically tunable fluidic antennas

Abstract: A method of manufacturing a fluidic structure is disclosed. A cavity that defines a shape of an element of the fluidic structure within a material is formed. The cavity is filled with liquid metal. The cavity is sealed. The fluidic structure behaves as an antenna. A fluidic antenna includes a material that defines a shape of the fluidic antenna by a cavity filled with liquid metal formed within the material, where the material further defines at least one mechanical property of the fluidic antenna.

Fluidics system for sequential delivery of reagents

Abstract: The invention provides a passive fluidics circuit for directing different fluids to a common volume, such as a reaction chamber or flow cell, without intermixing or cross contamination. The direction and rate of flow through junctions, nodes and passages of the fluidics circuit are controlled by the states of upstream valves (e.g. opened or closed), differential fluid pressures at circuit inlets or upstream reservoirs, flow path resistances, and the like. Free diffusion or leakage of fluids from unselected inlets into the common outlet or other inlets at junctions or nodes is prevented by the flow of the selected inlet fluid, a portion of which sweeps by the inlets of unselected fluids and exits the fluidics circuit by waste ports, thereby creating a barrier against undesired intermixing with the outlet flow through leakage or diffusion. The invention is particularly advantageous in apparatus for performing sensitive multistep reactions, such as pH-based DNA sequencing reactions.

Longitudinal vibration mode of piezoelectric thick-film cantilever-based sensors in liquid media

Abstract: We report on the fabrication of a self-actuated resonant-microsensor, based on a thick-film piezoelectric cantilever, dedicated to either (bio)chemical detection in gaseous or liquid media or fluid characterization. The aim of this paper is to demonstrate that longitudinal modes can be used in highly viscous environments. Lower levels of fluid-solid interaction in comparison with classical flexural modes are expected from the results of our analytical model of a cantilever oscillating in a fluid. For example, in various fluid ranging from air to a Newtonian fluid of 300 cP viscosity, measured quality factors for the first longitudinal mode range from 300 to 20.

Tuneable surface acoustic waves for fluid and particle manipulations on disposable chips

Abstract: We establish a powerful new acoustic technique to programme complex fluidic functions such as droplet movement, merging, mixing and concentration, on a disposable superstrate.

Fluidics apparatus and fluidics substrate

Abstract: A fluidics apparatus is disclosed for manipulation of at least one fluid sample, typically in the form of a droplet. The apparatus has a substrate surface with a sample manipulation zone for location of the fluid sample. A transducer arrangement such as an interdigitated electrode structure on a piezoelectric body provides surface acoustic waves at the substrate surface for manipulation of the fluid sample. The substrate surface has an arrangement of surface acoustic wave scattering elements forming a phononic crystal structure for affecting the transmission, distribution and/or behaviour of surface acoustic waves at the substrate surface. Also disclosed is a method for lysing a cell. In this method, the cell is comprised in a fluid sample contacting a substrate surface, the method comprising providing surface acoustic waves at the substrate surface, such that the cell lyses.

Integrated Liquid Cooling Systems for 3-D Stacked TSV Modules

Abstract: In this paper, an integrated liquid cooling system for 3-D stacked modules with high dissipation level is proposed. The fluidic interconnects in this system are elaborated and the sealing technique for different fluid interfaces is discussed. Meanwhile, the pressure drop for each part of the system is analyzed. The optimized fluidic interconnects minimizing the pressure drop have been designed and fabricated, and the compact system is integrated. In line with the fluidic interconnect design and analysis, an experimental process for hydraulic characterization of the integrated cooling system is established. The pressure drops for different fluidic interconnects in this system are measured and compared with the analyzed results.

Fluidic lens and method of manufacturing the same

Abstract: A fluidic lens and method for manufacturing the same are provided. The fluidic lens includes a transparent optical fluid and a double elastomer membrane. An outer membrane of the double elastomer membrane that is externally exposed includes a Poly DiMethyl Siloxane (PDMS) elastomer, and an inner membrane of the double elastmoer membrane that makes contact with the optical fluid is transparent and includes an elastomer which has a low coherence with respect to the optical fluid.

Nanostructure biosensors and systems and methods of use thereof

Abstract: A sensor scheme combining nano-photonics and nano-fluidics on a single platform through the use of free-standing photonic crystals and nanoplasmonic arrays is described. By harnessing nanoscale openings, both fluidics and light can be manipulated at sub-wavelength scales. The convective flow is actively steered through the nanohole openings for effective delivery of the analytes to the sensor surface, and refractive index changes are detected in aqueous solutions. Systems and methods using cross-polarization measurements to further improve the detection limit by increasing the signal-to-noise ratio are also described.

Microfluidic parallel circuit for measurement of hydraulic resistance

Abstract: We present a microfluidic parallel circuit that directly compares the test channel of an unknown hydraulic resistance with the reference channel with a known resistance, thereby measuring the unknown resistance without any measurement setup, such as standard pressure gauges. Many of microfluidic applications require the precise transport of fluid along a channel network with complex patterns. Therefore, it is important to accurately characterize and measure the hydraulic resistance of each channel segment, and determines whether the device principle works well. However, there is no fluidic device that includes features, such as the ability to diagnose microfluidic problems by measuring the hydraulic resistance of a microfluidic component in microscales. To address the above need, we demonstrate a simple strategy to measure an unknown hydraulic resistance, by characterizing the hydraulic resistance of microchannels with different widths and defining an equivalent linear channel of a microchannel with repeated patterns of a sudden contraction and expansion.

Ultimate and practical limits of fluid-based mass detection with suspended microchannel resonators

Abstract: Suspended microchannel resonators (SMRs) are an innovative approach to fluid-based microelectromechanical mass sensing that circumvents complete immersion of the sensor. By embedding the fluidics within the device itself, vacuum-based operation of the resonator becomes possible. This enables frequency shift-based mass detection with high quality factors, and hence sensitivity comparable to vacuum-based micromechanical resonators. Here we present a detailed analysis of the sensitivity of these devices, including consideration of fundamental and practical noise limits, and the important role of binding kinetics in sensing. We demonstrate that these devices show significant promise for protein detection. For larger, biologically-important targets such as rare whole virions, the required analysis time to flow sufficient sample through the sensor can become prohibitively long unless large parallel arrays of sensors or preconcentrators are employed.

Theoretical and experimental investigation of optically driven nanoelectromechanical oscillators

Abstract: The actuation of biologically functional micro- and nanomechanical structures using optical excitation is an emerging arena of research that couples the fields of optics, fluidics, electronics, and mechanics with potential for generating novel chemical and biological sensors In our work, we fabricated nanomechanical structures from 200 and 250 nm thick silicon nitride and single crystal silicon layers with varying lengths and widths ranging from 4 to 12 μm and 200 nm to 1 μm, respectively Using a modulated laser beam focused onto the device layer in close proximity to the clamped end of a cantilever beam, we concentrate and guide the impinging thermal energy along the device layer Cantilever beams coupled to chains of thermally isolated links were used to experimentally investigate energy transport mechanisms in nanostructures The nature of the excitation was studied through steady-periodic axisymmetric thermal analysis by considering a multilayered structure heated using a modulated laser source Res

Fluid interface cartridge for a microfluidic chip

Abstract: An interface cartridge for a microfluidic chip, with microfluidic process channels and fluidic connection holes at opposed ends of the process channels, provides ancillary fluid structure, including fluid flow channels and input and/or waste wells, which mix and/or convey reaction fluids to the fluidic connection holes and into the process channels of the microfluidic chip.

Thick film flow sensor for biological microsystems

Abstract: An anemometer for the in situ control of the flow rates in fluidic systems is designed, manufactured and characterized. For the first time, a flow sensor according to the boundary layer principle is manufactured with exclusive use of thick film technologies. This principle enables the application of the sensor for low fluid temperatures as required in biological fluid systems. The sensor is integrated in a retention module consisting of Low Temperature Cofired Ceramics (LTCC), which allow the cost-effective realisation of complex fluidic microsystems with integrated electronics by only using thick film technologies. Thermistor compositions are printed on a free-standing bridge and encapsulated to ensure biological compatibility. The encapsulation becomes possible by using an adapted technology. At the same time the design facilitates a maximal heat-insulation of the sensor element from the substrate. The control of the stress influences on the free-standing sensor bridge due to shrinking mismatch, TCE mismatch, density gradients and deformation during the lamination is investigated using design of experiments (DoE), resulting in an adapted design and fabrication process. The presented anemometer has a linear sensor characteristic for flow rates up to 80 μl/min. Compatibility investigations of LTCC with biological substances will be presented.

Method and apparatus for aerodynamic flow control using compact high-frequency fluidic actuator arrays

Abstract: The present invention is directed to the manufacture of and the use of an aerodynamic flow control device having a compact array of a plurality of fluidic actuators in planar, curved, circular and annular configurations. The compact array of fluidic actuators of the invention may be designed to produce oscillating or pulsed jets at the exit ports with frequencies in the range of 1-22 kHz. They may be integrally manufactured along with the wing sections, flaps, tail and rudder of airplane, the inlet or exit geometries of a jet engine. When supplied with a source of fluid such as air, these arrays of actuators produce a set of fluid jets of random phase of high velocity and influence the main stream of air over the subject surface. The beneficial effects of modifying flow using the present invention include increased lift, reduced drag, improved performance and noise reduction in jet engines.

Low-power microfluidic electro-hydraulic pump (EHP)

Abstract: Low-power electrolysis-based microfluidic pumps utilizing the principle of hydraulics, integrated with microfluidic channels in polydimethylsiloxane (PDMS) substrates, are presented. The electro-hydraulic pumps (EHPs), consisting of electrolytic, hydraulic and fluidic chambers, were investigated using two types of electrodes: stainless steel for larger volumes and annealed gold electrodes for smaller-scale devices. Using a hydraulic fluid chamber and a thin flexible PDMS membrane, this novel prototype successfully separates the reagent fluid from the electrolytic fluid, which is particularly important for biological and chemical applications. The hydraulic advantage of the EHP device arises from the precise control of flow rate by changing the electrolytic pressure generated, independent of the volume of the reagent chamber, mimicking the function of a hydraulic press. Since the reservoirs are pre-filled with reagents and sealed prior to testing, external fluid coupling is minimized. The stainless steel electrode EHPs were manufactured with varying chamber volume ratios (1 : 1 to 1 : 3) as a proof-of-concept, and exhibited flow rates of 1.25 to 30 µl/min with electrolysis-based actuation at 2.5 to 10 VDC. The miniaturized gold electrode EHPs were manufactured with 3 mm diameters and 1 : 1 chamber volume ratios, and produced flow rates of 1.24 to 7.00 µl/min at 2.5 to 10 VAC, with a higher maximum sustained pressure of 343 KPa, suggesting greater device robustness using methods compatible with microfabrication. The proposed technology is low-cost, low-power and disposable, with a high level of reproducibility, allowing for ease of fabrication and integration into existing microfluidic lab-on-a-chip and analysis systems.

Construction and characterisation of a modular microfluidic system: coupling magnetic capture and electrochemical detection

Abstract: This work presents the fabrication and characterisation of a versatile lab-on-a-chip system that combines magnetic capture and electrochemical detection. The system comprises a silicon chip featuring a series of microband electrodes, a PDMS gasket that incorporates the microfluidic channels, and a polycarbonate base where permanent magnets are hosted; these parts are designed to fit so that wire bonding and encapsulation are avoided. This system can perform bioassays over the surface of magnetic beads and uses only 50 μL of bead suspension per assay. Following detection, captured beads are released simply by sliding a thin iron plate between the magnets and the chip. Particles are captured upstream from the detector and we demonstrate how to take further advantage of the system fluidics to determine enzyme activities or concentrations, as flow velocity can be adjusted to the rate of the reactions under study. We used magnetic particles containing β-galactosidase and monitored the enzyme activity amperometrically by the oxidation of 4-aminophenol, enzymatically produced from 4-aminophenyl-β-d-galactopyranoside. The system is able to detect the presence of enzyme down to approximately 50 ng mL−1.

Three-dimensional microfluidic liquid-core/liquid-cladding waveguide

Abstract: This letter describes a three-dimensional liquid-core/liquid-cladding optical waveguide system. The core fluid was focused in the vertical direction by a transverse secondary flow (produced by a Dean vortex) and focused in the horizontal direction by two parallel sheath flows. The waveguide introduced less optical loss between the core fluid and the channel wall. Diffusion between the core fluid and the cladding fluid was reduced by high fluid velocities. The present system can be considered as a graded-index waveguide due to the diffusion effect. The width of the core fluid was manipulated by adjusting the sheath flow rates. Numerical simulations were conducted to support and interpret the experimental results.

Extended-nano fluidic systems for analytical and chemical technologies.

Abstract: Recently, integrated chemical systems have been further downscaled to the 101–103 nm scale, which we call extended-nano space. The extended-nano space is a transient space from single molecules to bulk condensed phase, and fluidics and chemistry have not been explored. One of the reasons is the lack of research tools for the extended-nano space, because the space locates the gap between the conventional nanotechnology (100–101 nm) and microtechnology (>1μm). For these purposes, basic methodologies were developed such as nanofabrication, fluidic control, detection methods, and surface modification methods. Especially, fluidic control is one of the important methods. By utilizing the methodologies, new specific phenomena in fluidics and chemistry were reported, and the new phenomena are increasingly applied to unique applications. Microfluidic technologies are now entering new research phase combined with the nanofluidic technologies. In this review, we mainly focus on pressure-driven or shear-driven extended-nano fluidic systems and illustrate the basic nanofluidics and the representative applications.

Detection and fluidic system of a flow cytometer

Abstract: The fluidic system including a sheath pump that pumps sheath fluid from a sheath container into an interrogation zone, a waste pump that pumps waste fluid from the interrogation zone to a waste container, in which the flow rate of the sheath fluid is different from the flow rate of the waste fluid thereby drawing a sample fluid from a sample container into the interrogation zone, a detection system that provides a data set of input signals from the sample fluid, an analysis engine that recognizes aggregate particle events in the data set, and a controller that automatically adjusts the flow rate of the sample fluid into the interrogation zone based on the recognition of aggregate particle events, by controlling at least one of the flow rates of the sheath fluid and the waste fluid.

Three-dimensional surface microfluidics enabled by spatiotemporal control of elastic fluidic interface

Abstract: As an emerging alternative to the conventional counterpart, surface microfluidics incorporates both intrinsic resistive solid-liquid and elastic frictionless gas-liquid interfaces, leading to unique flow-pressure characteristics. Furthermore, the open-surface microfluidic platforms can be fabricated on a monolithic substrate with high wettability contrast by the previously reported one-step lithographic process of a photosensitive superhydrophobic nanocomposite material, which permits flexible fluidic operations and direct surface modifications. In the paper, we first present three-dimensional microfluidic manipulations utilizing the unconventional gas-liquid interfaces of surface microfluidics, outlined by the micropatterned wetting boundaries (also known as the triple lines). In contrast to the primary linear (resistive) nature of the conventional closed-channel microfluidics, the distinct elastic interface of surface microfluidics enables remarkable three-dimensional (deformable) and time-dependent (capacitive) operations of the flow. Specifically, spatiotemporal dependence of microflow patterns on the planar fluidic surfaces has been theoretically analyzed and experimentally characterized. Utilizing the unconventional interface-enabled flow-pressure relationship, novel surface fluidic operations, including microflow regulation and flow-controlled switching, have been demonstrated and fully investigated. Furthermore, three-dimensional surface microfluidic networks together with analog-to-digital stereo-flow activations have been established, in which miniature capillary bridges form fluidic connections between two independent surface microfluidic circuits.

Fluidic oscillators for use with a subterranean well

Abstract: A well tool can comprise a fluid input, a fluid output and a fluidic oscillator which produces oscillations in a fluid which flows from the input to the output. The fluidic oscillator can include a vortex chamber with inlets, whereby fluid enters the vortex chamber alternately via the inlets, the inlets being configured so that the fluid enters the vortex chamber in different directions via the respective inlets, and a fluid switch which directs the fluid alternately toward different flow paths in response to pressure differentials between feedback fluid paths. The feedback fluid paths may be connected to the vortex chamber. The flow paths may cross each other between the fluid switch and the outlet.

Microfluidic probe: a new tool for integrating microfluidic environments and electronic wafer-probing

Abstract: We demonstrate a new tool for integrating microfluidic channels with commonly used electronic probing techniques. The “microfluidic probe” allows rapid and repeatable fluidic and electronic addressing of small die sites on a variety of substrate types without the need for permanent modification or dicing of the device wafers. We also use the probe to demonstrate locally patterned chemical modification of a substrate. The probes are easily fabricated using standard soft-lithography and basic machining making this a widely accessible technique for electronics and fluidics researchers.

A technique to design complex 3D lab on a chip involving multilayered fluidics, embedded thick electrodes and hard packaging—application to dielectrophoresis and electroporation of cells

Abstract: Nowadays, lab on chips (LOCs) require the development of new technologies in order to integrate complex fluidics, sensors, actuators, etc. Such integration requires overcoming both technological bottlenecks and an increase in production cost. We propose a technique to manufacture reusable and complex LOCs made up of SU-8 resist for the fluidic structure and of glass for the hard packaging, and are compatible with the integration of thick electrodes. The method is based on the combination of two bonding technologies, both based on a wafer bonder. The first one consists of the bonding of a thin photosensitive SU-8 dry film, which is similar to lamination. The second one is the standard bonding technique which uses a hard substrate covered by an SU-8 layer. The LOCs that can be obtained by combining these two methods are transparent, and include 3D microfluidic structures and thick electrodes. Moreover, these LOCs are reusable, packaged and ready to use. In order to validate the concept, we designed an LOC devoted to cell arraying, using dielectrophoresis, as well as to cell electroporation.

Electromagnetic control of coupled droplets

Abstract: Electromagnetism offers several advantages for moving capillary surfaces, including energy efficiency, fast response, and device integrability. Here, we demonstrate electromagnetic control of a pinned-contact, coupled droplet system using aqueous ferrofluids. A time-varying magnetic field provides the necessary perturbation to toggle millimeter scale capillary switches. Furthermore, periodic magnetic fields can drive coupled droplets at resonant frequencies approaching 100 Hz using only 1 V by balancing capillary forces with liquid inertia. These addressable devices may find applications in adaptive optics, fluidic actuators, and read-write arrays.

Hydraulic circuit for a power transmission device

Abstract: A hydraulic fluid circuit for a power transmission device includes a first hydraulic circuit segment fluidly decoupled from a second hydraulic circuit segment. A hydraulic pump includes a first fluidic pumping element and a second fluidic pumping element. The first fluidic pumping element fluidly communicates with the first hydraulic circuit segment. The second fluidic pumping element fluidly communicates with the second hydraulic circuit segment. The first fluidic pumping element is controllable to a first pump operating point to achieve a preferred high fluidic flow rate in the first hydraulic circuit segment. The second fluidic pumping element is controllable to a second pump operating point to achieve a preferred high fluidic pressure in the second hydraulic circuit segment.

Polymer-based micro flow sensor for dynamical flow measurements in hydraulic systems

Abstract: In this paper we present a micro flow sensor from a polymer for dynamical flow measurements in hydraulic systems. The flow sensor is based on the thermal anemometric principle and consists of two micro-structured housing shells from polysulfone (PSU) which form a small fluidic channel with a cross-section of 580 µm × 400 µm. In between there is a thin polyimide membrane supporting three gold track structures forming an electrical heater and two resistive thermometers which allows the detection of the flow direction, too. The complete sensor is inserted into the hydraulic system, but only a small bypass flow is directed through the fluidic channel by means of a special splitting system. Due to its small heat capacity, the sensor is suitable to detect flow pulsations up to about 1200 Hz which allows the sensor to be used for the condition monitoring or preventive maintenance of hydraulic systems.

Fluidic actuator and display device having fluidic actuators

Abstract: The fluidic actuator (12) according to the invention comprises a chamber (32B) filled with a fluid, an element (36) that is movable relative to the chamber (32B) and in contact with the fluid, as well as a passage (44) for circulating the fluid between the inside and the outside of the chamber (32B) so as to vary the quantity of fluid in the chamber and thus cause movement of the movable element (36). The fluid is magneto-rheological and the fluidic actuator (12) comprises magnetic field generation means (26, 28) arranged so as to generate, within the passage (44), a controlled magnetic field.

Programmable fluidic droplet generation

Abstract: A programmable fluidic device for generating droplets with resolutions of micrometer in size and milliseconds in generation timing is provided The programmable fluidic device has a valve forming a droplet cutter, which contains a fluid deflectable membrane capable of controlling the flow of a dispensing fluid from a fluidic dispensing channel The programmable fluidic device is able to perform temporal control over the droplet generation independent from the size control

Design and characterization of a magnetic digital flow regulator

Abstract: Design, fabrication and testing of a novel micromachined “quasi-digital” microflow regulator for integrated microfluidic systems. Operation relies on the use of a permanent magnet which interacts with an electrodeposited layer of Co–Ni on an array of V-shaped cantilever beams under a constant pressure. Each valve actuates as an on–off fluidic switch, opening or closing its corresponding microchannel. The flow can be adjusted to a set of different values (digital) by changing the position of the magnet. The microflow regulator has been designed, fabricated and experimentally tested showing a flow variation of 211% at a pressure of 160 mbar.