Abstract: A biological sample solution is ionized by electrospray and the sample solution is irradiated with an infrared laser beam to dissociate biological macromolecules into the constituents thereof. As a result, only non-covalent bonds of the biological macromolecules can be selectively severed and analyzed.

Abstract: A microfluidic device with a vertical injection aperture is provided. The microfluidic device comprises a separation channel, an injection aperture disposed adjacent to and in fluid communication with the separation channel. The microfluidic device further comprises a semi-permeable filter disposed adjacent to the injection aperture, wherein the filter is configured to preconcentrate a sample in the injection aperture to form a preconcentrated sample plug during an injection operation, and wherein the sample plug flows downwardly from the injection aperture to the separation channel during an electrophoresis operation.

Abstract: The present invention relates to microfluidic systems having components with specially designed and fabricated areas of enhanced and/or reduced capillarity (flow guides). The methods and devices of the present invention permit the bubble-less dispensing and mixing of small volumes of different liquids for subsequent incubation and/or detection of products of various biological reactions. Thus present invention is well-suited to applications such as polymerase chain reaction and capillary electrophoresis.

Abstract: A multiplexed, absorbance-based microfabricated chip electrophoresis system, microfabricated chip, and method of use are included for the detection and identification of protein species. The microfabricated chip electrophoresis system capable of analyzing multiple samples simultaneously. The system uses a microfabricated chip having a sample chamber for first dimension separation of a sample, a first planar array of channels for second dimension separation of the sample approximately perpendicular the sample chamber, and a barrier separating the sample chamber from the first planar array of channels during the first dimension separation. In use, the sample is placed into a sample chamber, a barrier is established around the sample chamber, the sample is isoelectric focused within the sample chamber, the barrier is then removed, and the sample separated in the first array of channels by molecular weight.

Abstract: A method of separating components having a given negative or positive charge and contained in a sample is disclosed. The method involves, in one embodiment, loading a microchannel with a sample, placed between a trailing-edge electrolyte having a selected concentration of a titratable species, and a leading-edge electrolyte.

Abstract: A device for transporting and focusing ions in a low vacuum or atmospheric-pressure region of a mass spectrometer is constructed from a plurality of longitudinally spaced apart electrodes to which oscillatory (e.g., radio-frequency) voltages are applied. In order to create a tapered field that focuses ions to a narrow beam near the device exit, the inter-electrode spacing or the oscillatory voltage amplitude is increased in the direction of ion travel.

Abstract: The present invention provides, in one aspect, an apparatus or electrophoretic separation of analytes. In one aspect, the apparatus comprises a disc-shaped substrate defining (1) a central reservoir region, (2) a plurality of electrophoretic channels in fluid communication with, and emanating substantially radically from, the central reservoir region, the channels being coplanar with each other, and each channel having (i) a proximal end which is linked to the reservoir region, and (ii) a distal end, and preferably (3) for each channel, at least one chamber, and preferably three chambers, linked by a passageway in fluid communication with the distal end of that channel.

Abstract: A software-driven device named the Microfluidic Central Processing Unit (?fCPU). The device is a chamber encompassing a contiguous physical volume equipped with actuators (electrodes, pressure membranes or other) capable of inducing physical forces on liquids, gases and particles contained in it, for the purpose of performing at least the 5 basic microfluidics operations: mixing, concentration, separation, transport and reaction within one integrated chamber. The device can have one volume where all of the operations are performed or can be spatially divided into several “processing areas” between which there are transport routes enabled by the software-regulated actuation. A device that contains more than one ?fCPU employed in parallel or in series or both. A device that is composed of one or more than one ?fCPU's and where fluids and particles are transported using a central pump together with integrated micropumps.

Abstract: A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microchannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Abstract: Use of a support material for capillary electrochromatography (CEC), characterized in that the support material has a porous design and a surface which consists of an outer surface and a pore surface, wherein the outer surface has regions of different derivatization and/or functionality from that of the pore surface.

Abstract: A microfluidic device includes a microfluidic circuit, having an axis, and an electric field generator, arranged to establish an electric field (E) within at least a section of the microfluidic circuit, the electric field (E) being oriented transversally to the axis. The electric field is used to locally concentrate charged molecules, thus increasing the reaction rate.

Abstract: Methods for detecting one or more analytes, such as a protein, in a fluid path are provided. The methods include resolving, immobilizing and detecting one or more analytes in a fluid path, such as a capillary. Also included are devices and kits for performing such assays.

Abstract: Plastic electrophoresis separation chips are provided comprising a plurality of microfluidic channels and a detection window, where the detection window comprises a thin plastic; and the detection window comprises a detection region of each microfluidic channel. Such chips can be bonded to a support provided an aperture is provided in the support to allow detection of samples in the electrophoresis chip at the thin plastic detection window. Further, methods for electrophoretically separating and detecting a plurality of samples on the plastic electrophoresis separation chip are described.

Abstract: In a case where the temperature of capillaries cannot be controlled rapidly in accordance with the change of the amount of heat generated from the capillaries, the phoretic speed of the sample is not controlled constant to lower the analyzing performance for the sample. This invention intends to stabilize the electrophoretic speed. The surface of a substrate on which a plurality of capillaries are arranged is in contact with a member capable of temperature control thereby controlling the temperature of the capillaries. Since a member capable of controlling the temperature and the capillaries are in direct contact with each other according to the invention, the temperature of the capillary can be controlled rapidly at a high accuracy, so that electrophoretic speed is stabilized.

Abstract: An electrophoresis analysis method and apparatus capable of maintaining high reliability upon a repeated use of the same gel. A heat transfer medium selected from the group consisting of solids, liquids and gels is filled in substantially all of the gaps between the electrode and each capillary. A hollow electrode into which a capillary is inserted has a plurality of retaining shapes such that the capillary can be fixed at the center of the electrode. The heat from the capillary can be efficiently dissipated via the electrode, and also the temperature increase in the capillary can be prevented. Further, temperature increases due to the heating of the capillaries during operation can be controlled and thereby thermal deterioration of the gel can be prevented.

Abstract: Provided is a capillary electrophoresis device including a holder preventing a septum from coming off when a capillary is pulled out, and also allowing containers to be taken out in any order. In the capillary electrophoresis device for separating and analyzing a sample such as a DNA and a protein by electrophoresis, the holder includes: a septum having a capillary hole through which a capillary penetrates; a container for storing a solution; and a container-accommodation unit for accommodating the container. A hole formed in the septum engages with an engagement portion formed on the container, and thereby the septum is held to cover the container.

Abstract: The invention relates to a device for electrophoretically separating molecules. The inventive device comprises: at least one plate having a top side and an underside; a first separating channel provided for receiving at least one first separating medium; at least one second channel, which is orthogonal to said first separating channel and which is provided for receiving a second separating medium; optionally comprises implements provided for filling the device with reagents, solvents, buffers, separating media and/or for loading the device with a sample to be separated, and; terminals for applying electric separating voltage to the separating channels. In the device, the first separating channel is located on the plate top side and comprises at least one first opening that leads to the plate underside, whereby the second separating channel is located on the plate underside and comprises at least one second opening.

Abstract: A multi-capillary electrophoresis apparatus is provided for reducing errors during analysis caused by fluctuations in electrophoresis time among plural capillaries of the apparatus. The multi-capillary electrophoresis apparatus can contain a multi-capillary array that has a separation medium filled therein for isolating a sample. A detector component can be provided at a position remote from a sample injecting end of the array for acquiring information from the sample. A buffer container can be provided for holding a buffer solution into which the sample injecting end can be immersed. One or more temperature controlling component devices can be arranged for controlling a temperature of the buffer solution, of the detector component, or of both the buffer solution and the detector component.

Abstract: Described is a fluidic microsystem (100) including at least one channel (10) through which a particle suspension can flow; and first and second electrode devices (40, 60) which are arranged on first and second channel walls (21, 31) for generating electrical alternating-voltage fields in the channel (10); wherein the first electrode device (40) for field shaping in the channel includes at least one first structure element (41, 51); and the second electrode device (60) includes an area-like electrode layer (61) with a closed second electrode surface which includes a second passivation layer (70); wherein the effective electrode surface of the first structure element (41, 51), of which element (41, 51) there is at least one, is smaller than the second electrode surface; and the second passivation layer (70) is a closed layer which completely covers the second electrode layer (61).

Abstract: In a system for operation or handling of a laboratory microchip (41) for chemical processing or analysis, the microchip (41) is mounted in a first physical unit (42). The microchip (41) is arranged on a mounting plate, such that it is readily accessible from the top and thus the fitting and removal of the microchip is considerably simplified. Furthermore, the first physical unit (42) comprises an optical device (43) for contactless detection of the results of the chemical processes conducted on the microchip. The supply systems necessary for the operation of the microchip are arranged in a module unit that has a separable connection with a second physical unit. The proposed modular layout enables ease of interchangeability of the required supply systems and thus, overall, ease of adaptability of the proposed system for various types of microchips.

Abstract: A capillary array includes multiple capillaries and two holding substrates for arranging the aforementioned multiple capillaries in a substantially plane surface by sandwiching at least some of these capillaries mutually. One of the holding substrates has a detection window for transmitting the detected light emitted by a test sample by irradiation of light. Especially, this detection window includes multiple light transmission areas provided to correspond to each capillary to transmit the detected light, and light cut-off areas provided between these light transmission areas to cut off the detected light. These light cut-off areas cut off light reflected from the surface of capillaries and hence improve the SN ratio, thereby ensuring high-precision detection.

Abstract: Disclosed herein is an apparatus for the separation of proteins, comprising a capillary isoelectric focusing unit (2) for primarily separating protein samples on the basis of pi; and a hollow fiber flow field flow fractionation unit (4), connected to one side of the capillary isoelectric focusing unit (2), for secondarily separating the protein samples. The apparatus allows proteins to be separated on the basis of pi and molecular weight without denaturation and can further be applied for the identification of proteins in conjunction with nanoflow liquid chromatography-electrospray ionization-tandem mass spectrometry after enzymatic digestion of the protein fractions.

Abstract: An aqueous liquid medium for analyzing, purifying or separating species in an element having walls or for treating the walls of an element. The medium includes at least a polymer consisting of several polymeric segments. The polymer is of the irregular block-copolymer or irregular comb-like polymer type and has on the average at least three junction points between polymeric segments of different chemical or topological nature. The medium may be used in methods for analyzing, purifying or separating species and methods for treating an element to be contacted with a fluid and/or species contained in the fluid during preservation, transport, analysis, purification or separation of the fluid.

Abstract: A multi-capillary array which can be used for a multi-capillary electrophoresis apparatus to effectively disperse the heat generated within a load header. In a load header of the capillary array used for the multi-capillary electrophoresis, an insulated holder, a connection plate and tubular electrodes are closely arranged without substantial formation of gaps. The heat generated within the load header can be dispersed effectively to the external side by eliminating an air-layer within the load header.

Abstract: A method of discharging a fluid flow with suspended microparticles from a fluidic microsystem (10) is described, whereby the fluid flow converges with at least one output flow to form a discharge flow at the end of a discharge channel (14) of the microsystem, and the discharge flow is delivered through a conduction element (19). A microsystem with a flow output device for implementation of this method is also described.

Abstract: Accordance to various embodiments, there are methods of separating molecules, devices, and method of making the devices. The method of separating molecules can include providing a nanofluidic device including a plurality of nanochannels on a top surface of a substrate, wherein each of the plurality of nanochannels has a first end and a second end and extends from the top surface into the substrate. The nanofluidic device can also include a dielectric layer disposed over each of the plurality of nanochannels, an inlet at the first end of the plurality of nanochannnels, an outlet at the second end of the plurality of nanochannels, and an optically transparent cover disposed over the plurality of nanochannels to form a seal. The method of separating molecules can further include providing a solution in the plurality of nanochannels through the inlet and creating a longitudinal pH gradient along each of the plurality of nanochannels.

Abstract: The present invention concerns methods, compositions and apparatus for detection and/or determination of concentration of target molecules. In preferred embodiments the methods comprise allowing target molecules to form a complex with a first binding agent conjugated to a detection molecule and a second binding agent conjugated to a capture molecule, allowing the complex to further bind to an essentially uncharged polymer capable of binding to the capture agent, and performing a vertical gradient electrophoresis to separate the complex from unbound target, first and second binding agents and polymer. The intact complex is concentrated by electrophoresis at a stacking layer and the detection molecule is detected and/or quantified. Because the complex contains a very high mass to charge ratio, it becomes essentially immobile at the stacking layer, while unbound components migrate through the stacking layer and are separated from the complex.

Abstract: An electrochemical detector integrated on a capillary electrophoresis chip according to the present invention includes: a first substrate having a microchannel; a second substrate adapted to mate with the first substrate and having at least one peripheral electrode for conducting electrophoresis of a sample injected along the microchannel of the first substrate, in which a separation channel is formed along the microchannel by bonding the first substrate with the second substrate; a first electrode, made of indium tin oxide (ITO), formed on the first substrate to be positioned over the separation channel; and a second electrode, made of indium tin oxide (ITO), formed on the second substrate to be positioned under the separation channel, and spaced apart from the first electrode at a predetermined interval, wherein the first electrode and the second electrode constitute a detector to measure electrical characteristics of the sample passing along the separation channel.

Abstract: A variety of elastomeric-based microfluidic devices and methods for using and manufacturing such devices are provided. Certain of the devices have arrays of reaction sites to facilitate high throughput analyses. Some devices also include reaction sites located at the end of blind channels at which reagents have been previously deposited during manufacture. The reagents become suspended once sample is introduced into the reaction site. The devices can be utilized with a variety of heating devices and thus can be used in a variety of analyses requiring temperature control, including thermocycling applications such as nucleic acid amplification reactions, genotyping and gene expression analyses.

Abstract: New high density microfluidic devices and methods provide precise metering of fluid volumes and efficient mixing of the metered volumes. A first solution is introduced into a segment of a flow channel in fluidic communication with a reaction chamber. A second solution is flowed through the segment so that the first solution is displaced into the reaction chamber, and a volume of the second solution enters the chamber. The chamber can then be isolated and reactions within the chamber can be initiated and/or detected. High throughput methods of genetic analysis can be carried out with greater accuracy than previously available.

Abstract: A microchannel structure including a dispersed-phase introduction channel which communicates with a dispersed-phase introduction inlet; a continuous-phase introduction channel which communicates with a continuous-phase introduction inlet; a discharge channel which communicates with a discharge outlet; a fine-particle formation channel; and a plurality of branch channels for dispersed-phase introduction which are microchannels; wherein one end of the fine-particle formation channel in a fluid traveling direction communicates with the continuous-phase introduction channel whereas the other end thereof communicates with the discharge channel; and wherein a side part of the dispersed-phase introduction channel and side part of the fine-particle formation channel communicate via the plurality of branch channel for dispersed-phase introduction.

Abstract: A microfluidic device and method for forming and dispensing minute volume segments of a material are described. In accordance with the present invention, a microfluidic device and method are provided for spatially confining the material in a focusing element. The device is also adapted for segmenting the confined material into minute volume segments, and dispensing a volume segment to a waste or collection channel. The device further includes means for driving the respective streams of sample and focusing fluids through respective channels into a chamber, such that the focusing fluid streams spatially confine the sample material. The device may also include additional means for driving a minute volume segment of the spatially confined sample material into a collection channel in fluid communication with the waste reservoir.

Abstract: One of the principal objects of the present invention is to realize, in a small scale and at a low cost, an analyzing apparatus that analyzes and manipulates a minute sample such as DNA. The analyzing apparatus 1 incorporates an optical system for measuring a fluorescence from a sample traveling through a minute channel 24c. Specifically, a light source that generates a light for exciting a fluorescence of the sample and a light guide that guides the light from the light source to the minute channel 24c are provided, whereby the fluorescence of the sample in the minute channel 24c is well excited. In order to observe the fluorescence of the sample, a condensing optical element 26, provided on a wall surface of the minute channel 24c, for capturing the fluorescence from the sample, and a sensor section 11 are provided, whereby the fluorescence of the sample in the minute channel 24c can be well observed.

Abstract: The present invention provides a method for producing a high-quality capillary tube used in an electrophoresis apparatus in a safe and inexpensive manner. A polymer coating on a capillary tube is converted into gas and removed through an oxidative reaction with oxygen radicals resulting from ozone decomposition.

Abstract: An apparatus and methods for concentrating samples for application to microfluidic devices are disclosed. The methods involve electrophoresing charged molecules from a high volume sample into a smaller volume. The analyte of interest can be a charged molecule or can be modified to be charged using, for example, one or more ionic moieties.

Abstract: The present disclosure provides various means for optimizing fluid transport in micro and nanofluidic devices. Such means may be used to construct fluidic devices specifically suited to particular tasks such as molecular and biomolecular sensing and analysis, biosensors for clinical diagnostics; memory devices; screening devices for pharmaceutical applications; the provision of biologically functionalized surfaces; high throughput screening for pharmaceutical applications; controlled drug delivery; medical diagnosis; environmental monitoring; chemical and biological warfare agent sequestration; actuator development; power sources; transistors; diodes; electrochemical pumps; and bio-fuel cell development. The present disclosure further provides methods of controlling the direction of electric current and fluid flow in such devices.

Abstract: To reduce the elongation of the migration time for the first electrophoresis cycle in successive electrophoresis cycles and improve the reliability of electrophoresis analysis. The present invention relates to making the condition of a migration medium at the start of the first electrophoresis analysis in successive electrophoresis analyses after the temperature in a thermostatic oven reaches a desired preset temperature substantially the same as the conditions after the successive electrophoresis analyses. Preferably, a voltage is applied to a separation medium filling a capillary during preheating of the thermostatic oven. Preferably, the temperature in the thermostatic oven during preheating is set higher than the temperature in the thermostatic oven during electrophoresis analysis. Preferably, a buffer solution is heated during preheating of the thermostatic oven. Preferably, the capillary is filled with a preheated separation medium during preheating of the thermostatic oven.

Abstract: Disclosed is an apparatus and method for the mixing of two microfluidic channels wherein several wells are oriented diagonally across the width of a mixing channel. The device effectively mixes the confluent streams with electrokinetic flow, and to a lesser degree, with pressure driven flow. The device and method may be further adapted to split a pair of confluent streams into two or more streams of equal or non-equal concentrations of reactants. Further, under electrokinetic flow, the surfaces of said wells may be specially coated so that the differing electroosmotic mobility between the surfaces of the wells and the surfaces of the channel may increase the mixing efficiency. The device and method are applicable to the steady state mixing as well as the dynamic application of mixing a plug of reagent with a confluent stream.

Abstract: A microfluidic device including a microfluidic chip assembled to an electrospray structure. The microfluidic chip includes at least one microfluidic channel leading through an outlet aperture to a surface area of the microfluidic chip. The electrospray structure includes at least one thin, planar point provided with a capillary slot that terminates at the end of the point so as to form an aperture for ejection of a liquid to be sprayed. The electrospray structure is arranged on the surface area of the microfluidic chip so that the point is cantilivered with respect to the microfluidic chip and so that the outlet aperture of the microfluidic device leads to the capillary slot of the point, which microfluidic device also has a mechanism to apply an electrospray voltage to the liquid to be sprayed.

Abstract: A microfluidic device and method is disclosed having one or more membranes for the control of electrolysis. In one embodiment, a microfluidic device is disclosed that includes body with first channel and second channels separated by a gel layer. A first electrode positioned in the first channel and a second electrode positioned in the second channel wherein a potential applied to the first and second electrodes passes electrons from the first channel to the second channel through the gel layer. In another embodiment, a microfluidic device includes a body having a surface with a channel separating two first reservoirs. One or more membranes are positioned on the surface covering a portion of the channel and a blank is positioned covering the channel and the one or more membranes. A second reservoir through the blank is in contact with the membrane, each second reservoir in communication with the channel via the membrane.

Abstract: The present invention discloses a high-density parallel channel design for a microfabricated capillary array electrophoresis chip, with vertical T or double T design for sample injection. An alternative embodiment of the invention includes a closed buffer reservoirs with integrated electrodes and buffer feeding ports. Also disclosed are novel sample loading and injection methods, including the use of using either a capillary array connected to an electrode, or an array of metal pens as the loader/electrode.

Abstract: Variable potential electrokinetic devices and electrokinetic multipliers used for pumping and flow control are disclosed that offer improvements in safety and design flexibility. The devices of the present invention take advantage of combinations of pumping conduits and conducting conduits to permit the use of lower operating voltages in pumps, pressure multipliers, and flow controllers. Devices having N pumping stages and 2N+1 electrodes permit the use of arbitrary voltages at the fluid connection points between the devices and other system components, further improving device safety and flexibility.

Abstract: In a device to operate and handle a laboratory microchip to chemically process or analyze substances, the microchip is on a chip holder (41) that is part of a first assembly (42). The first assembly (42) also has an optical device (43) for contactless detection of the results of the chemical processes carried out on the microchip. A supply device (56) required to operate the microchip is in a module releasably connected to a second assembly (44, 55). In particular, the second assembly (44, 55) has an intermediate carrier (57) that is releasably connected to the supply device (56). The intermediate carrier has continuous electrical paths (60) or connecting channels that can bridge electrodes (58) or supply channels of the supply device (56) and the assigned counterelectrodes (53) of the microchip. There are correspondingly connecting lines (61) to bridge the supply of materials.

Abstract: A capillary array electrophoretic device capable of securing a sample plate array and a buffer container three dimensionally on a tray of an autosampler. A tray (700) is provided with a guide groove (701) and a stopper (702) corresponding to guides (715, 716) of sample plate assemblies (710, 711) including a microtiter plate.

Abstract: An electrophoretic system having a plurality of separation lanes is provided with an automatic calibration feature in which each lane is separately calibrated. For each lane, the calibration coefficients map a spectrum of received channel intensities onto values reflective of the relative likelihood of each of a plurality of dyes being present. Individual peaks, reflective of the influence of a single dye, are isolated from among the various sets of detected light intensity spectra, and these can be used to both detect the number of dye components present, and also to establish exemplary vectors for the calibration coefficients which may then be clustered and further processed to arrive at a calibration matrix for the system. The system of the present invention thus permits one to use different dye sets to tag DNA nucleotides in samples which migrate in separate lanes, and also allows for in-situ calibration with new, previously unused dye sets.

Abstract: A microfabricated device employing a bridging membrane and methods for electrokinetic transport of a liquid phase biological or chemical material using the same are described. The bridging membrane is deployed in or adjacent to a microchannel and permits either ionic current flow or the transport of gas species, while inhibiting the bulk flow of material. The use of bridging membranes in accordance with this invention is applicable to a variety of processes, including electrokinetically induced pressure flow in a region of a microehannel that is not influenced by an electric field, sample concentration enhancement and injection, as well as improving the analysis of materials where it is desired to eliminate electrophoretic bias. Other applications of the bridging membranes according to this invention include the separation of species from a sample material, valving of fluids in a microchannel network, mixing of different materials in a microchannel, and the pumping of fluids.

Abstract: An electrophoretic apparatus that allows bubbles to be readily removed out of an electrophoretic passage. The passage for electrophoretic medium, at a connecting section where capillaries filled with electrophoretic medium are connected with a pumping mechanism for filling the electrophoretic medium, is arranged such that the side of the pumping mechanism is disposed below the side of the capillaries, so that the electrophoretic medium flows from down to up at the connecting section when filling the electrophoretic medium into the capillaries. Preferably, the passage between the capillary array and the buffer solution is controlled by using a rotary-type valve having high withstand pressure to simplify the passage structure. The dead volume of the passage can be reduced and the valuable electrophoretic medium can be efficiently used. The amount of used electrophoretic medium required for the removal of the bubble can be also reduced.

Abstract: A first electrophoretic medium comprises an electrically charged particle suspended in a suspending fluid, the particle having a polymeric shell having repeating units derived from at least one monomer the homopolymer of which is incompatible with the suspending fluid. A second, similar electrophoretic medium comprises a suspending fluid, and first and second types of electrically charged particle suspended in the suspending fluid, the two types of particle having differing optical characteristics but both having polymeric shells. The polymeric shells are arranged such that homoaggregation of the two types of particles is thermodynamically favored over heteroaggregation.

Abstract: The present invention improves the performance of microchannel systems for chemical and biological synthesis and analysis by providing a method and apparatus for producing a thin band of a species sample. Thin sample bands improve the resolution of microchannel separation processes, as well as many other processes requiring precise control of sample size and volume. The new method comprises a series of steps in which a species sample is manipulated by controlled transport through a junction formed at the intersection of four or more channels. A sample is first inserted into the end of one of these channels in the vicinity of the junction. Next, this sample is thinned by transport across the junction one or more times. During these thinning steps, flow enters the junction through one of the channels and exists through those remaining, providing a divergent flow field that progressively stretches and thins the band with each traverse of the junction.

Abstract: A projection-type imaging array comprising a plurality of microfluidic devices (1, 1?) are provided, each microfluidic device having a reservoir (30) containing first and second fluids (10 and 20) that are immiscible with respect to teach other. A drive unit (40) is provided for each microfluidic device to selectively displace the surface formed at the interface between the first and second fluids. Accordingly, when a particular microfluidic device is turned OFF according to the drive unit, the interface surface is positioned to redirect incoming light (via reflection/refraction) away from a display surface (80). Conversely, when the microfluidic device is turned ON, the interface surface is positioned so that the incoming light is directed toward the display surface.