Abstract: The invention provides microfluidic devices with embedded fluidic impedances. Such impedances do not allow fluid to pass at a low differential pressure, but allow fluid to flow at a higher differential pressure. Impedances are formed by the three dimensional overlap of two or more channels contained within layers of the device. Such devices can be rapidly protyped and can be assembled to contain multiple fluidic impedances to perform complex fluid handling tasks, including metering defined volumes of samples and dividing samples into aliquots.

Abstract: Microfluidic coupling devices capable of connecting more than one microfluidic module together to form a larger, integrated system are described. These devices are constructed in a number of ways. In a certain embodiments, the coupler is constructed from laminated materials and mates to one or more microfluidic devices using adhesive. The device can be used to place fluid into a microfluidic device, to remove fluid from a microfluidic device, or to transfer fluid between two or more microfluidic devices. Also described are modular microfluidic systems formed from microfluidic modules made using various techniques and/or useful for performing various functions.

Abstract: Systems and methods for metering microfluidic volumes are provided. A discrete plug may be separated from a larger volume of first fluid by injecting a second fluid, such as a gas, into a channel containing the first fluid. The injection of the second fluid to isolate the desired amount of the first fluid may be controlled through timing of flows, visual indicators and/or automated control systems using optical or electrical sensors.

Abstract: Microfluidic devices having porous materials that restrict fluid flow rate for a given pressure are provided. Multiple porous regions can be constructed in a single device so that they have different valving capabilities or impedances, and in unison can control the overall direction of fluid flow. Porous regions can be constructed in various ways, such as, for example: by inserting porous materials into or between channels; by sandwiching one or more sheets or layers of porous materials between other layers of a device; or by inserting a liquid, solution, slurry, or suspension into a microfluidic channel and then permitting the formation of porous deposits by promoting at least partial evaporation. Adhesive tape may be used for one or more layers of such a microfluidic device.

Abstract: In accordance with the present invention there is provided a microfluidic heat exchange system for cooling heat-generating components of electronic equipment, computers, lasers, analytical instruments, medical equipment and the like. Both direct contact and indirect contact microfluidic systems are described. Also described are microfluidic systems that incorporate remote heat rejection systems that may be located outside the body of the equipment that contains the heat generating components that need cooling.

Abstract: Microfluidic devices for splitting an established fluidic flow through a microfluidic channel among multiple downstream microfluidic channels include a plurality of elevated flow resistance regions to promote precise and predictable splitting. Each elevated resistance region imparts a flow resistance that is substantially greater than the characteristic resistance to established flow of its associated downstream channel. Elevated flow resistance regions may include one or more porous materials and/or alterations to the channel geometry of at least a portion of a downstream channel.

Abstract: Microfluidic devices having a plurality of functional features for performing one or more fluidic operations in parallel are provided. Reagents, samples or other fluids common to multiple functional features (“common fluids”) may be input into a microfluidic device or system through one or more distributing inputs that divide and distribute the common fluids as desired. The use of a multi-layer fabrication technique allows multiple distributing inputs to distribute to multiple functional features in a microfluidic device without undesirable fluid channel intersections.

Abstract: Microfluidic devices capable of combining discrete fluid volumes generally include channels for supplying different fluids toward a sample chamber and means for establishing fluid communication between the fluids within the chamber. Discrete fluid plugs are defined from larger fluid volumes before being combined. Certain embodiments utilize adjacent chambers or subchambers divided by a rupture region such as a frangible seal. Further embodiments utilize one or more deformable membranes and/or porous regions to direct fluid flow. Certain devices may be pneumatically or magnetically actuated.

Abstract: Multi-layer microfluidic devices incorporating a filter element are provided. A filter element is compressively restrained between device layers, such that the compression promotes a tight seal between device layers and resists fluid leakage around the filter element.

Abstract: Modular microfluidic systems includes a plurality of microfluidic modules, each capable of performing fluidic operations including, but not limited to, filtering, splitting, regulating pressure, mixing, metering, reacting, diverting, heating, cooling, and condensing are provided. The microfluidic modules are polymeric, stencil-based structures adapted to be coupled in sequence for performing biological or chemical synthesis, including, but not limited to, chemical and biological syntheses of organic, polymer, inorganic, oligonucleotide, peptide, protein, bacteria, and enzymatic products.

Abstract: A microfluidic reactor for performing chemical and biological synthesis reactions, including chemical and biological syntheses of organic, polymer, inorganic, oligonucleotide, peptide, protein, bacteria, and enzymatic products is provided. Two fluids are input into the device, mixed in a mixing region and provided to a long, composite reaction channel. Fluids flowing through the reaction channel may be diverted at a diversion region into a sample channel. Fluids in the sample channel may be mixed at a second region, with additional reagents.

Abstract: Multi-layer microfluidic splitting devices are provided. A common fluid inlet fluidly communicates with a branching channel network that evenly divides a fluid flow to a plurality of outlets. Even splitting is provided by maintaining substantially equal fluidic impedance across all branch channels. Substantially equal fluidic impedance may be provided by maintaining a substantially equal flow path length between the common inlet and each of the outlets. The use of multiple device layers permits fabrication of such a device without geometrically complex channel structures, high feature density, and two-dimensional outlet arrays.

Abstract: Microfluidic fraction collectors fractionating a sample stream into discrete sample volumes are provided. Fluid flow control mechanisms divert selected portions of a sample stream from an inlet channel into one or more branch channels. The fluid flow control mechanisms may be passive, relying on sample volume and fluidic impedance to establish the sample collection sequence. Alternatively, active fluid flow control mechanisms may be controlled, with or without feedback, to establish the sample collection sequence.

Abstract: Microfluidic devices and methods for metering discrete plugs of fluid are provided. The microfluidic devices include a trunk channel and a branch channel having an impedance region. A fluid is supplied to the trunk channel and fills the branch channel to the impedance region. The fluid is then flushed from the trunk channel leaving the branch channel filled. Because the branch channel has a volume, a discrete plug of the fluid having a volume substantially equal to that of the branch channel is formed.

Abstract: Microfluidic flow control devices are provided. In one embodiment, a regulating device includes overlapping channel segments separated by a deformable membrane in fluid communication with one another. Pressure differentials between the channel segments deform the membrane towards the channel with the lower pressure, thereby restricting flow.

Abstract: Microfluidic devices and methods for metering discrete plugs of fluid are provided. The microfluidic devices include a trunk channel and a branch channel having an impedance region. A fluid is supplied to the trunk channel and fills the branch channel to the impedance region. The fluid is then flushed from the trunk channel leaving the branch channel filled. Because the branch channel has a volume, a discrete plug of the fluid having a volume substantially equal to that of the branch channel is formed.

Abstract: Microfluidic devices for splitting an established fluidic flow through a microfluidic channel among multiple downstream microfluidic channels include a plurality of elevated flow resistance regions to promote precise and predictable splitting. Each elevated resistance region imparts a flow resistance that is substantially greater than the characteristic resistance to established flow of its associated downstream channel. Elevated flow resistance regions may include one or more porous materials and/or alterations to the channel geometry of at least a portion of a downstream channel.

Abstract: A modular microfluidic system includes a plurality of discrete microfluidic modules each capable of performing at least one operation and at least one microfluidic coupling device for fluidically coupling the modules to perform a sequence of operations. The microfluidic modules and coupling devices may be constructed according to various techniques. In one embodiment, coupling devices are fabricated from multiple layers and each include a fluidic inlet port, a fluidic outlet port, and at least one sandwiched stencil layer having a microfluidic channel formed therein. Also described are integrated microfluidic systems and methods capable of performing various sequences of operations.

Abstract: Multi-layer microfluidic devices with convoluted channels and densely positioned microfluidic structures are provided. Desirable microfluidic structures which, if cut in a single device layer, would be subject to deformation, may be created from multiple, non-deforming layers. Channel segments of any geometry defined in separate layers communicate to form continuous flow paths that in turn form the desirable microfluidic structures. Any number of device layers may be used to fabricate the microfluidic structures as desired.

Abstract: Microfluidic separators for separating multiphase fluids are described. Two or more microfluidic outlet channels within the device meet at an overlap region. The overlap region may be in fluid communication with an inlet channel. The inlet channel and each outlet channel are disposed within different layers of a three-dimensional device. A multiphase fluid flows through an inlet channel into an overlap region from where the separated phases can be withdrawn through the outlet channels.