Abstract: Microfluidic structures and methods for manipulating fluids, fluid components, and reactions are provided. In one aspect, such structures and methods can allow production of droplets of a precise volume, which can be stored/maintained at precise regions of the device. In another aspect, microfluidic structures and methods described herein are designed for containing and positioning components in an arrangement such that the components can be manipulated and then tracked even after manipulation. For example, cells may be constrained in an arrangement in microfluidic structures described herein to facilitate tracking during their growth and/or after they multiply.

Abstract: The present invention generally relates to droplets and/or emulsions, such as multiple emulsions. In some cases, the droplets and/or emulsions may be used in assays, and in certain embodiments, the droplet or emulsion may be hardened to form a gel. In some aspects, a heterogeneous assay can be performed using a gel. For example, a droplet may be hardened to form a gel, where the droplet contains a cell, DNA, or other suitable species. The gel may be exposed to a reactant, and the reactant may interact with the gel and/or with the cell, DNA, etc., in some fashion. For example, the reactant may diffuse through the gel, or the hardened particle may liquefy to form a liquid state, allowing the reactant to interact with the cell. As a specific example, DNA contained within a gel particle may be subjected to PCR (polymerase chain reaction) amplification, e.g., by using PCR primers able to bind to the gel as it forms. As the DNA is amplified using PCR, some of the DNA will be bound to the gel via the PCR primer.

Abstract: Parallel uses of microfluidic methods and devices for focusing and/or forming discontinuous sections of similar or dissimilar size in a fluid are described. In some aspects, the present invention relates generally to flow-focusing-type technology, and also to microfluidics, and more particularly parallel use of microfluidic systems arranged to control a dispersed phase within a dispersant, and the size, and size distribution, of a dispersed phase in a multi-phase fluid system, and systems for delivery of fluid components to multiple such devices.

Abstract: The present invention generally relates to droplets and/or emulsions, such as multiple emulsions. In some cases, the droplets and/or emulsions may be used in assays, and in certain embodiments, the droplet or emulsion may be hardened to form a gel. In some aspects, a heterogeneous assay can be performed using a gel. For example, a droplet may be hardened to form a gel, where the droplet contains a cell, DNA, or other suitable species. The gel may be exposed to a reactant, and the reactant may interact with the gel and/or with the cell, DNA, etc., in some fashion. For example, the reactant may diffuse through the gel, or the hardened particle may liquefy to form a liquid state, allowing the reactant to interact with the cell. As a specific example, DNA contained within a gel particle may be subjected to PCR (polymerase chain reaction) amplification, e.g., by using PCR primers able to bind to the gel as it forms. As the DNA is amplified using PCR, some of the DNA will be bound to the gel via the PCR primer.

Abstract: The present invention generally relates to microparticles and, in particular, to systems and methods for encapsulation within microparticles. In one aspect, the present invention is generally directed to microparticles containing entities therein, where the entities contain an agent that can be released from the microparticles, e.g., via diffusion. In some cases, the agent may be released from the microparticles without disruption of the microparticles. The entities may be, for instance, polymeric particles, hydrogel particles, droplets of fluid, etc. The entities may be contained within a fluid that is, in turn, encapsulated within the microparticle. The agent may be released from the entity into the fluid, and then from the fluid through the microparticle. In such fashion, the release of agent from the microparticle may be controlled, e.g., over relatively long time scales.

Abstract: The invention relates to microparticles comprising a crosslinked gel and methods for making and using same.

Abstract: This invention generally relates to particle-assisted nucleic acid sequencing. In some embodiments, sequencing may be performed in a microfluidic device, which can offer desirable properties, for example, minimal use of reagents, facile scale-up, and/or high throughput. In one embodiment, a target nucleic acid may be exposed to particles having nucleic acid probes. By determining the binding of the particles to the target nucleic acid, the sequence of the target nucleic acid (or at least a portion of the target nucleic acid) can be determined. The target nucleic acid may be encapsulated within a fluidic droplet with the particles having nucleic acid probes, in certain instances. In some cases, the sequence of the target nucleic acid may be determined, based on binding of the particles, using sequencing by hybridization (SBH) algorithms or other known techniques.

Abstract: The invention describes a method for the identification of compounds which bind to a target component of a biochemical system or modulate the activity of the target, comprising the steps of: a) compartmentalising the compounds into microcapsules together with the target, such that only a subset of the repertoire is represented in multiple copies in any one microcapsule; and b) identifying the compound which binds to or modulates the activity of the target; wherein at least one step is performed under microfluidic control. The invention enables the screening of large repertoires of molecules which can serve as leads for drug development.

Abstract: The present invention generally relates to microparticles and, in particular, to systems and methods for encapsulation within microparticles. In one aspect, the present invention is generally directed to microparticles containing entities therein, where the entities contain an agent that can be released from the microparticles, e.g., via diffusion. In some cases, the agent may be released from the microparticles without disruption of the microparticles. The entities may be, for instance, polymeric particles, hydrogel particles, droplets of fluid, etc. The entities may be contained within a fluid that is, in turn, encapsulated within the microparticle. The agent may be released from the entity into the fluid, and then from the fluid through the microparticle. In such fashion, the release of agent from the microparticle may be controlled, e.g., over relatively long time scales.

Abstract: A system and method are provided for harvesting target biological substances. The system includes a substrate and a first and second channel formed in the substrate. The channels longitudinally extending substantially parallel to each other. A series of gaps extend from the first channel to the second channel to create a fluid communication path passing between a series of columns with the columns being longitudinally separated by a predetermined separation distance. The system also includes a first source configured to selectively introduce into the first channel a first biological composition at a first channel flow rate and a second source configured to selectively introduce into the second channel a second biological composition at a second channel flow rate. The sources are configured to create a differential between the first and second channel flow rates to generate physiological shear rates along the second channel that are bounded within a predetermined range.

Abstract: Microfluidic structures and methods for manipulating fluids, fluid components, and reactions are provided. In one aspect, such structures and methods can allow production of droplets of a precise volume, which can be stored/maintained at precise regions of the device. In another aspect, microfluidic structures and methods described herein are designed for containing and positioning components in an arrangement such that the components can be manipulated and then tracked even after manipulation. For example, cells may be constrained in an arrangement in microfluidic structures described herein to facilitate tracking during their growth and/or after they multiply.

Abstract: The invention describes a method for the identification of compounds which bind to a target component of a biochemical system or modulate the activity of the target, comprising the steps of: a) compartmentalizing the compounds into microcapsules together with the target, such that only a subset of the repertoire is represented in multiple copies in any one microcapsule; and b) identifying the compound which binds to or modulates the activity of the target; wherein at least one step is performed under microfluidic control. The invention enables the screening of large repertoires of molecules which can serve as leads for drug development.

Abstract: Microfluidic structures and methods for manipulating fluids, fluid components, and reactions are provided. In one aspect, such structures and methods can allow production of droplets of a precise volume, which can be stored/maintained at precise regions of the device. In another aspect, microfluidic structures and methods described herein are designed for containing and positioning components in an arrangement such that the components can be manipulated and then tracked even after manipulation. For example, cells may be constrained in an arrangement in microfluidic structures described herein to facilitate tracking during their growth and/or after they multiply.

Abstract: Various aspects of the present invention relate to the control and manipulation of fluidic species, for example, in microfluidic systems. In one set of embodiments, droplets may be sorted using surface acoustic waves. The droplets may contain cells or other species. In some cases, the surface acoustic waves may be created using a surface acoustic wave generator such as an interdigitated transducer, and/or a material such as a piezoelectric substrate. The piezoelectric substrate may be isolated from the microfluidic substrate except at or proximate the location where the droplets are sorted, e.g., into first or second microfluidic channels. At such locations, the microfluidic substrate may be coupled to the piezoelectric substrate (or other material) by one or more coupling regions. In some cases, relatively high sorting rates may be achieved, e.g., at rates of at least about 1,000 Hz, at least about 10,000 Hz, or at least about 100,000 Hz, and in some embodiments, with high cell viability after sorting.

Abstract: A system and method are provided for harvesting target biological substances. The system includes a substrate and a first and second channel formed in the substrate. The channels longitudinally extending substantially parallel to each other. A series of gaps extend from the first channel to the second channel to create a fluid communication path passing between a series of columns with the columns being longitudinally separated by a predetermined separation distance. The system also includes a first source configured to selectively introduce into the first channel a first biological composition at a first channel flow rate and a second source configured to selectively introduce into the second channel a second biological composition at a second channel flow rate. The sources are configured to create a differential between the first and second channel flow rates to generate physiological shear rates along the second channel that are bounded within a predetermined range.

Abstract: This invention generally relates to systems and methods for the formation and/or control of fluidic species, and articles produced by such systems and methods. In some cases, the invention involves unique fluid channels, systems, controls, and/or restrictions, and combinations thereof. In certain embodiments, the invention allows fluidic streams (which can be continuous or discontinuous, i.e., droplets) to be formed and/or combined, at a variety of scales, including microfluidic scales. In one set of embodiments, a fluidic stream may be produced from a channel, where a cross-sectional dimension of the fluidic stream is smaller than that of the channel, for example, through the use of structural elements, other fluids, and/or applied external fields, etc. In some cases, a Taylor cone may be produced.

Abstract: The present invention generally relates to microfluidics and, in some embodiments, to the determination of cells. In some aspects, primers able to introduce restriction sites into certain amplified nucleic acids are used. For example, the primers may introduce restriction sites into normal (wild-type) nucleic acids, but be unable to introduce restriction sites into mutant nucleic acids, e.g., due to a mismatch in the nucleic acid sequences caused by the mutant. After amplification, the nucleic acids may be exposed to a suitable restriction enzyme, which may cleave normal nucleic acids but not the mutant nucleic acids. In this way, mutant nucleic acids may be relatively quickly identified. In some embodiments, cells may be contained within microfluidic droplets and assayed to determine the mutant cells. In certain cases, for example, the nucleic acids may be amplified within droplets and attached to suitable tags, e.g., prior to breaking or merging the droplets and sequencing of the nucleic acids.

Abstract: The present invention generally relates to multiple emulsions, and to methods and apparatuses for making multiple emulsions. A multiple emulsion generally describes larger droplets that contain one or more smaller droplets therein. The larger droplets may be suspended in a third fluid in some cases. These can be useful for encapsulating species such as pharmaceutical agents, cells, chemicals, or the like. In some cases, one or more of the droplets can change form, for instance, to become solidified to form a microcapsule, a liposome, a polymerosome, or a colloidosome. Multiple emulsions can be formed in one step in certain embodiments, with generally precise repeatability, and can be tailored to include one, two, three, or more inner droplets within a single outer droplet (which droplets may all be nested in some cases).

Abstract: The present invention generally relates to microfluidic droplets and, including forming gels within microfluidic droplets. In some aspects, a fluid containing agarose or other gel precursors is transported into a microfluidic droplet, and caused to harden within the droplet, e.g., to form a gel particle contained within the microfluidic droplet. Surprisingly, a discrete gel particle may be formed even if the fluid containing the agarose or other gel precursor, and the fluid contained within the microfluidic droplet, are substantially immiscible. Other aspects of the present invention are generally directed to techniques for making or using such gels within microfluidic droplets, kits containing such gels within microfluidic droplets, or the like.

Abstract: The present invention generally relates to systems and methods for determining RNA in blood or other fluids. In certain embodiments, blood or other fluids may be treated to isolate or separate RNA, for example, from DNA, cells, and other material. In some cases, the RNA may arise from bacteria or other pathogens or foreign organisms that may be found within the blood or other fluid. In some cases, RNA stabilizing reagents, such as ammonium sulfate, may be added to stabilize RNA, then cells within the blood may be lysed to release the RNA (and other materials) from the cells, thereby producing a lysate. The lysate may be treated, e.g., to separate nucleic acids from other components within the lysate, and in some cases, DNA may be degraded, e.g., using DNAses or other suitable enzymes, leaving behind the RNA. The RNA can then be studied, purified, analyzed, amplified, stored, or the like.