Abstract: Apparatus and Method for Handling Fluids at Nano-Scale Rates. A linear displacement pump produces non-pulsatile liquid flow rates as low as the nl/mm range. The pump includes a servo motor, a gear reduction, a lead screw, a linear stage, a barrel, and a plunger extending into the barrel and coupled to the stage. A microfluidic interconnect device can be coupled to the barrel. One or more of these pumps can be disposed in a thermally controlled pump assembly that includes a pump housing, a thermally conductive body disposed in the housing and including first and second opposing sides, and a temperature regulating element such as a thermoelectric device disposed in thermal contact with the thermally conductive body on a side thereof opposite to the barrel or barrels of the pumps.

Abstract: Microfluidic Systems, Devices and Methods for Reducing Noise Generated by Mechanical Instabilities. According to one embodiment, a microfluidic device is provided for reducing noise in a fluid mix. The microfluidic device can include microscale channels for passage of fluids to a mixing junction. The mixing channel can be adapted to combine the fluids into a common fluid flow. The microfluidic device can also include a connector channel including first and second ends. The first end of the connector channel can be connected to the mixing junction. The microfluidic device can also include an expansion channel having connection to the second end of the connector channel. The expansion channel can be adapted for passage of the fluid mix through the expansion channel to reduce concentration gradient noise of the fluid mix by dispersion of the fluid mix as the fluid mix passes through the expansion channel.

Abstract: According to one embodiment, a microfluidic system and method is disclosed for reducing autofluorescence. The microfluidic system can include a light source for generating an excitation light. The microfluidic system can also include a microscope having an objective for focusing the excitation light on a fluid inside a microfluidic channel of a microfluidic chip. Further, the microfluidic system can include a detector for rejecting out-of-focus light emitted from the microfluidic chip.

Abstract: A microfluidic system comprising: at least one microfluidic channel, the inner surface of which is fluorinated or fluorous; and a pump for supplying a flow of an aqueous medium containing chemical reagents or assay components to said microfluidic channel. Preferably, the apparatus further comprises a supply of a non-aqueous medium which is compatible with the surface of the microfluidic channel but immiscible with the aqueous medium, such as a perfluorocarbon solvent, for forming a sheath around the flowing aqueous medium whereby the aqueous medium is suspended away from the surface of the microfluidic channel. Also provided are methods for carrying out a chemical reaction or a biological assay in the microfluidic systems of the subject matter disclosed herein.

Abstract: Methods for measuring biochemical reactions and analysis of reaction products by controlling dispersion of reagents within fluid streams such that the measuring of the biochemical reaction is substantially free of a measurable dispersion artifact. Controlling dispersion of reagents within fluid streams can include flowing multiple fluid streams each including reaction reagents into contact through a mixing region to laterally mix the fluid streams and then passing the merged, laterally mixed fluid stream through a controlled dispersion element to axially disperse the reaction reagents merged fluid stream. Controlling dispersion of reagents within fluid streams can include controlling flow rates of multiple fluid streams each including reaction reagents to create a concentration gradient that is substantially free of a measurable dispersion artifact. The biochemical reaction can occur in a microfluidic chip.

Abstract: A junction is made between a first microfluidic substrate (12) having an elongate component (303) protruding from it and a second microfluidic substrate (22) having a corresponding conduit (261). Each of the substrates has a pair of alignment features, for example planar orthogonal surfaces (13,15; 23,25) or grooves (141,151; 241, 251) in opposite sides of the substrate. The substrates are placed on an alignment jig 6 having location features (63, 65) corresponding to the alignment features. The elongate component can be surrounded by a compressible gasket 40). The substrates are pushed towards each other so that the elongate component enters the conduit and the gasket, if any, is compressed. A fluid-tight junction results so long as the substrates are maintained in the necessary position, either by permanent means, or, if a junction which can be disassembled is needed, by maintaining pressure between the substrates.

Abstract: A fuel cell system having a fuel cell, the fuel cell having a membrane-electrode assembly; a fuel reservoir containing a liquid fuel; a conduit coupling the fuel reservoir to the fuel cell; and an electrokinetic fuel pump coupled to the conduit, the electrokinetic fuel pump having a plurality of electrodes; wherein the electrokinetic fuel pump moves fuel from the fuel reservoir through the conduit to the fuel cell; and wherein the electrokinetic fuel pump electrodes do not deleteriously affect the performance of the membrane-electrode assembly.

Abstract: A method of pumping fluid including the steps of providing an electrokinetic pump comprising a pair of double-layer capacitive electrodes having a capacitance of at least 10?2 Farads/cm2 and being connectable to a power source, a porous dielectric material disposed between the electrodes and a reservoir containing pump fluid; connecting the electrodes to a power source; and moving pump fluid out of the reservoir substantially without the occurrence of Faradaic processes in the pump. The invention also includes an electrokinetic pump system having a pair of double-layer capacitive electrodes having a capacitance of at least 10?2 Farads/cm2; a porous dielectric material disposed between the electrodes; a reservoir containing pump fluid; and a power source connected to the electrodes; the electrodes, dielectric material and power source being adapted to move the pump fluid out of the reservoir substantially without the occurrence of Faradaic processes in the pump.

Abstract: The pumps (Pn) are operated to transport individual reagent streams into the chip in a non-pulsatile, laminar flow regime at low flow rates permitting lows grading from 0 to as little as 5 nl/min with a precision of 0.1 nl/min. In the chip (MFC), the reagent streams are merged and the reagents mixed to form a reaction product. The reaction product can be measured at one or more detection points defined in the chip. Concentration gradients are continuously varied by continuously varying the flow rates respectively produced by the pumps according to predetermined flow velocity profiles.

Abstract: A precision flow controller is capable of providing a flow rate less than 100 microliters/minute and varying the flow rate in a prescribed manner that is both predictable and reproducible where the accuracy and precision of the flowrate is less than 5% of the flow rate. A plurality of variable pressure fluid supplies pump fluid through a single outlet. Flowmeters measure the flow rates and a controller compares the flow rates to desired flowrates and, if necessary, adjusts the plurality of variable pressure fluid supplies so that the variable pressure fluid supplies pump fluid at the desired flow rate. The variable pressure fluid supplies can be pneumatically driven.

Abstract: A non-Newtonian fluid is used in an electrokinetic device to produce electroosmotic flow therethrough. The nonlinear viscosity of the non-Newtonian fluid allows the electrokinetic device to behave differently under different operating conditions, such as externally applied pressures and electric potentials. Electrokinetic devices can be used with a non-Newtonian fluid in a number of applications, including but not limited to electrokinetic pumps, flow controllers, diaphragm valves, and displacement systems.

Abstract: An electrokinetic pump achieves high and low flow rates without producing significant gaseous byproducts and without significant evolution of the pump fluid. A first feature of the pump is that the electrodes in the pump are capacitive with a capacitance of at least 10?4 Farads cm2. A second feature of the pump is that it is configured to maximize the potential across the porous dielectric material. The pump can have either or both features.

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: A laminated flow device comprises a porous material encapsulated within bonding material. The porous material forms a flow path and the bonding material forms an enclosure surrounding the flow path. Micro-components, such as capillaries, electrodes, reservoirs, bridges, electrokinetic elements, and detectors, can be encapsulated within the device.

Abstract: A microfluidic detection device provides reduced dispersion of axial concentration gradients in a flowing sample. The microfluidic detection device includes a cell body and a flow path through the cell body. The flow path has an inlet segment, an outlet segment, and a central segment, which forms a detection cell. The central segment is located between and at an angle with both the inlet segment and the outlet segment. The central segment has a first junction with the inlet segment and a second junction with the outlet segment. The cell body contains two arms that can transmit light to and from the detection cell. At least a portion of a first arm is located in the first junction and at least a portion of a second arm is located in the second junction. The portions of the arms located in the junctions are situated so that fluid entering or exiting the central segment of the flow path flows around the outer surface of one of the portions.

Abstract: Microfluidic systems including a principal microfluidic conduit (24), an adjacent dead volume (1) and a drain conduit (70) which mitigates the adverse effects of the dead volume on the operation of the system.

Abstract: In accordance with the present invention, stable electroosmotic flow systems and methods for designing the same are disclosed. The invention provides electroosmotic flow systems comprising electroosmotic flow elements, including bridge elements, that have matching flux ratios, i.e., when two or more elements of an electroosmotic flow system are in fluidic and electrical communication at a junction, the flux ratio for each of the elements is selected so that the difference in flux ratios system adjacent two elements is less than a target value. The invention also provides methods for designing such systems.

Abstract: A device for microfluidic control comprising a regulator that is moveable in a conduit where the regulator is a composite polymer formed from a composite mixture comprising a polymerizable precursor and a particulate filler.

Abstract: An electrokinetic device is capable of operating for extended periods of time, e.g. days to a week, without producing significant gaseous byproducts and without significant evolution of the pump fluid. Features of the electrokinetic device include: the electrodes in the electrokinetic device are capacitive with a capacitance of at least 10?4 Farads/cm2; at least part of the inner surfaces of the electrodes have an area greater than the effective area of the porous dielectric material; at least part of the inner surfaces of the electrodes have a current flux less than 20 microamperes/cm2; and at least part of the inner surfaces of the electrodes have a current flux that varies by less than a factor of two. The electrokinetic device can have one or several of these features in any combination.

Abstract: In accordance with the present invention, stable electroosmotic flow systems and methods for designing the same are disclosed. The invention provides electroosmotic flow systems comprising electroosmotic flow elements, including bridge elements, that have matching flux ratios, i.e., when two or more elements of an electroosmotic flow system are in fluidic and electrical communication at a junction, the flux ratio for each of the elements is selected so that the difference in flux ratios system adjacent two elements is less than a target value. The invention also provides methods for designing such systems.