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 liquid sample is prepared at a preparation site and then processed, e.g. in an HPLC column. The sample is prepared and conveyed to the device at a flow rate which is substantially less than the flow rate through the device. The different flow rates are preferably provided by variable rate working fluid supplies which drive the sample from the preparation site and through the device.

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 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 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 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 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: 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 liquid sample is prepared at a preparation site and then processed, e.g. in an HPLC column. The sample is prepared and conveyed to the device at a flow rate which is substantially less than the flow rate through the device. The different flow rates are preferably provided by variable rate working fluid supplies which drive the sample from the preparation site and through the device.

Abstract: A liquid sample is prepared at a preparation site and then processed, e.g. in an HPLC column. The sample is prepared and conveyed to the device at a flow rate which is substantially less than the flow rate through the device. The different flow rates are preferably provided by variable rate working fluid supplies which drive the sample from the preparation site and through the device.

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 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 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 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 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: A method for controlling fluid flow at junctions in microchannel systems. Control of fluid flow is accomplished generally by providing increased resistance to electric-field and pressure-driven flow in the form of regions of reduced effective cross-sectional area within the microchannels and proximate a channel junction. By controlling these flows in the region of a microchannel junction it is possible to eliminate sample dispersion and cross contamination and inject well-defined volumes of fluid from one channel to another.

Abstract: A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by fluid pressure (either liquid or gas) against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.

Abstract: A variable flow rate injector provides accurate, precise, and reproducible injection volumes that have low dispersion. The invention is particularly well-suited for HPLC injection volumes <500 nL but can be used to inject larger volumes and in different applications as well. Injections are performed at a first flow rate and separations are performed at a second flow rate. For improved HPLC system performance, the first flow rate is less than the second flow rate. The injector uses a variable flow rate fluid supply that allows rapid switching between flow rates desired for injection and flow rates desired for separations.

Abstract: A cast-in-place and lithographically shaped mobile, monolithic polymer element for fluid flow control in microfluidic devices and method of manufacture. Microfluid flow control devices, or microvalves that provide for control of fluid or ionic current flow can be made incorporating a cast-in-place, mobile monolithic polymer element, disposed within a microchannel, and driven by fluid pressure (either liquid or gas) against a retaining or sealing surface. The polymer elements are made by the application of lithographic methods to monomer mixtures formulated in such a way that the polymer will not bond to microchannel walls. The polymer elements can seal against pressures greater than 5000 psi, and have a response time on the order of milliseconds. By the use of energetic radiation it is possible to depolymerize selected regions of the polymer element to form shapes that cannot be produced by conventional lithographic patterning and would be impossible to machine.

Abstract: A variable flow rate injector provides accurate, precise, and reproducible injection volumes that have low dispersion. The invention is particularly well-suited for HPLC injection volumes <500 nL but can be used to inject larger volumes and in different applications as well. Injections are performed at a first flow rate and separations are performed at a second flow rate. For improved IIPLC system performance, the first flow rate is less than the second flow rate. The injector uses a variable flow rate fluid supply that allows rapid switching between flow rates desired for injection and flow rates desired for separations.