Abstract: A solar fuels generation system includes a first reactor that contains a first solution in which a charge carrier is reduced to a reduced charge carrier. The system also includes a second reactor that contains a second solution in which the reduced charge carrier reduces protons so as to generate hydrogen gas.

Abstract: Chromatographic separation devices include multiple batch-processed columns joined by a body structure and adapted to perform parallel analyses. Both slurry-packed and monolithic column embodiments are provided. One or more liquid-permeable frits of various types may be used to retain stationary phase material within columns. A fluidic distribution network may be used to distribute stationary phase material and/or mobile phase solvents to multiple columns. Separation devices, including microfluidic embodiments, may be fabricated with various materials including polymers. Multi-column fabrication and separation methods are provided.

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: Systems and methods are provided for preparing samples for chromatographic separations and then chromatographically separating the prepared samples, preferably in a high-throughput fashion utilizing multiple parallel first (fluid) processing regions in fluid communication with multiple parallel second (fluid) processing regions wherein the each second processing region includes a chromatography column. One or more common fluid supplies may be utilized in each of the sample preparation and separation steps to minimize the number of requisite fluid connections and external components such as pumps, reservoirs, pulse dampers, flow controllers, and the like.

Abstract: A threadless interface for a fluidic system includes a microfluidic device having an outer surface and an internal near-surface channel having a first width and disposed at a first depth relative to the outer surface, with the first width being less than about two times the first depth. A fluidic seal engages the outer surface and exerts an elevated contact pressure against at least a portion of the outer surface without substantially occluding the channel. A preferred seal includes a raised boss. A fault tolerant flow path design can accommodate misalignment between adjacent device layers without detrimentally affecting fluid flow capability. The interface may be used in a microfluidic system for performing parallel analyses such as high performance liquid chromatography.

Abstract: Fluidic systems, including microfluidic systems, are used to manipulate light by light-fluid interaction so as to affect reflection, refraction, absorption, optical filtering, or scattering of the beam. One or more fluids may be provided to a channel or chamber and exposed to an incident beam, and the proportion of at least one of a plurality of fluids may be varied. Light may interact with a discrete fluid plug subject to movement within a channel. One or more flexible members may be employed, such as to provide a variable lens. Fluidic optical devices may be used in applications including optical switching, optical filtering, or optical processing. Multiplexed fluidic optical systems are further provided.

Abstract: Microfluidic analytical devices and systems have at least one porous element disposed downstream of one or more optical detection regions in a pressure-based separation system. A porous element elevates the backpressure within an optical detection region, thus suppressing bubble formation and enhancing optical detection. Various types of porous elements include porous membranes, packed particulate material, and polymerized monoliths. Preferred devices may be fabricated with substantially planar device layers, including stencil layers, that are directly bonded without adhesives to form a substantially sealed microstructure suitable for performing pressure-based chromatographic separations at elevated operating pressures and with organic solvents.

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 efficiently mixing two or more fluid are provided. Two or more microfluidic inlet channels defined in different sheets of material meet at an overlap region in fluid communication with an outlet channel. The channels are defined through the entire thickness of stencil sheets. The overlap region may include an aperture-defining spacer layer, and/or an impedance element, such as a porous membrane, adapted to distribute at least one fluid across the entire width of the outlet channel to promote reliable fluid mixing.

Abstract: Pressure-driven microfluidic separation devices, such as may be used for performing high performance liquid chromatography, are provided. Multiple separation columns may be defined in a single device and packed with stationary phase material retained by porous frits. One or more splitters may be provided to distribute slurry and/or mobile phase among multiple separation columns. In one embodiment, separation devices are substantially planar and fabricated with multiple device layers. Systems and methods employing slurry for packing separation devices are also provided.

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: Robust microfluidic mixing devices mix multiple fluid streams passively, without the use of moving parts. In one embodiment, these devices contain microfluidic channels that are formed in various layers of a three-dimensional structure. Mixing may be accomplished with various manipulations of fluid flow paths and/or contacts between fluid streams. In various embodiments, structures such as channel overlaps, slits, converging/diverging regions, turns, and/or apertures may be designed into a mixing device. Mixing devices may be rapidly constructed and prototyped using a stencil construction method in which channels are cut through the entire thickness of a material layer, although other construction methods including surface micromachining techniques may be used.

Abstract: Microfluidic devices with multiple fluid process regions for subjecting similar samples to different process conditions in parallel are provided. One or more common fluid inputs may be provided to minimize the number of external fluid supply components. Solid materials such as chromatographic separation media or catalyst media is preferably provided in each fluid process region. Solid materials may be supplied to the devices in the form of slurry, with particles retained by porous elements or frits. Different fluid process regions may having different effective lengths, different solid material types or amounts, or may receive different ratios of common fluids supplied to the device. The flow resistances of dissimilar fluid process regions may be balanced passively with the addition of impedance elements in series with each fluid process region.

Abstract: Robust microfluidic mixing devices mix multiple fluid streams passively, without the use of moving parts. In one embodiment, these devices contain microfluidic channels that are formed in various layers of a three-dimensional structure. Mixing may be accomplished with various manipulations of fluid flow paths and/or contacts between fluid streams. In various embodiments, structures such as channel overlaps, slits, converging/diverging regions, turns, and/or apertures may be designed into a mixing device. Mixing devices may be rapidly constructed and prototyped using a stencil construction method in which channels are cut through the entire thickness of a material layer, although other construction methods including surface micromachining techniques may be used.

Abstract: A splitter for multi-layer microfluidic devices is provided. The splitter includes multiple forked channels defined in two or more device layers. The forked channels communicate fluidically at overlap regions. The overlap regions, in combination with symmetrical channel geometries balance the fluidic impedance in the system and promote even splitting.

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: Microfluidic devices with multiple fluid process regions for subjecting similar samples to different process conditions in parallel are provided. One or more common fluid inputs may be provided to minimize the number of external fluid supply components. Solid materials such as chromatographic separation media or catalyst media is preferably provided in each fluid process region. Solid materials may be supplied to the devices in the form of slurry, with particles retained by porous elements or frits. Different fluid process regions may having different effective lengths, different solid material types or amounts, or may receive different ratios of common fluids supplied to the device. The flow resistances of dissimilar fluid process regions may be balanced passively with the addition of impedance elements in series with each fluid process region.

Abstract: Systems and methods are provided for preparing samples for chromatographic separations and then chromatographically separating the prepared samples, preferably in a high-throughput fashion utilizing multiple parallel first (fluid) processing regions in fluid communication with multiple parallel second (fluid) processing regions wherein the each second processing region includes a chromatography column. One or more common fluid supplies may be utilized in each of the sample preparation and separation steps to minimize the number of requisite fluid connections and external components such as pumps, reservoirs, pulse dampers, flow controllers, and the like.

Abstract: Non-planar microfluidic devices and methods for transferring fluids between vessels and microfluidic devices are provided. The devices may be contoured to physically contact non-planar vessels, such as pipes, tubes, vials, or syringes to establish fluid communication between a vessel and a microfluidic device. Devices according to the invention may be constructed from flexible, rigid, or combinations of flexible and rigid materials. In certain embodiments, microfluidic devices are composed of sandwiched stencils, and self-adhesive tapes may be used for one or more layers. A microfluidic device may be removably attached to a vessel with a non-permanent adhesive or adhesive layer. Continuously wrapped microfluidic devices fashioned from a single layer, in addition to rewindable microfluidic devices constructed from multiple layers, are provided. A multi-plunger syringe permits a microfluidic device or other reservoir coupled to the vessel to be filled on the draw stroke of the syringe plunger.

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.