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 front the microfluidic substrate except at or proximate the location where the droplets arc 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: The present invention generally relates to microfluidics and labeled nucleic acids. For example, certain aspects are generally directed to systems and methods for labeling nucleic acids within microfluidic droplets. In one set of embodiments, the nucleic acids may include “barcodes” or unique sequences that can be used to distinguish nucleic acids in a droplet from those in another droplet, for instance, even after the nucleic acids are pooled together. In some cases, the unique sequences may be incorporated into individual droplets using particles and attached to nucleic acids contained within the droplets (for example, released from lysed cells). In some cases, the barcodes may be used to distinguish tens, hundreds, or even thousands of nucleic acids, e.g., arising from different cells or other sources.

Abstract: The present invention generally relates to microfluidics and labeled nucleic acids. Certain aspects are generally directed to containing cells in gels, such as agarose gels, and determining nucleic acids within the cells, e.g., while contained within the gels. The nucleic acids may be, for example, genomic DNA, mRNA, transcriptomes, or the like. In some embodiments, for instance, both genomic DNA and RNA (e.g., as in a transcriptome) from a cell may be determined. In some cases, the nucleic acids may be attached to beads for sequencing or other purposes. Such systems may be useful, for example, for high-throughput sequencing or other applications.

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 subject 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 microfluidics and labeled nucleic acids. Certain aspects are generally directed to containing cells in gels, such as agarose gels, and determining nucleic acids within the cells, e.g., while contained within the gels. The nucleic acids may be, for example, genomic DNA, mRNA, transcriptomes, or the like. In some embodiments, for instance, both genomic DNA and RNA (e.g., as in a transcriptome) from a cell may be determined. In some cases, the nucleic acids may be attached to beads for sequencing or other purposes. Such systems may be useful, for example, for high-throughput sequencing or other applications.

Abstract: The present invention generally relates to fluidic droplets and systems and methods for determining immune or other cells. Some aspects of the invention are generally directed to assays that combine sensitive detection of secreted products with detection of target cell death in droplets containing an effector cell, systems and methods to isolate droplets in which one or more cell interactions have occurred, or systems and methods to generate nucleic acid information from cell interactions. In addition, some embodiments of the invention are generally directed to containing two (or more) cells in droplets, e.g., an effector cell and one or more target cells, and determining various interactions between the cells within the droplets, such as whether the effector cell kills the target cell, whether the effector cell releases antibodies, cytokines or other substances that are able to interact with the target cell or are released in the presence of the target cell, or the like.

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. 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 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 polymers and, in particular, to copolymers for stabilizing, e.g., emulsions or droplets. In certain aspects, the copolymers may comprise a relatively hydrophobic monomer and a relatively hydrophilic monomer polymerized together (e.g., randomly) to form the copolymer. Examples of hydrophobic monomers include methacrylates and vinylphenyls; examples of hydrophilic monomers include boronic acids or acid derivatives. Surprisingly, such random copolymers may act as surfactants, e.g., stabilizing droplets within the emulsion. In addition, in some cases, an interfacial film may be produced by exposing the copolymer to a complexing molecule, such as a polyol, that can complex with the copolymer to form the film. In some cases, the film may at least partially surround a droplet, and in certain embodiments, the film may be sufficiently sturdy such that the droplet can be removed from the emulsion.

Abstract: Techniques Nuc-seq, Div-Seq, and Dronc-Seq are allow for unbiased analysis of any complex tissue. Nuc-Seq, a scalable single nucleus RNA-Seq method, can sensitively identify closely related cell types, including within the adult hippocampus. Div-seq combines Nuc-Seq with EdU-mediated labeling of proliferating cells, allowing tracking of transcriptional dynamics of newborn neurons in an adult neurogenic region in the hippocampus. Dronc-Seq uses a microfluidic device to co-encapsulate individual nuclei in reverse emulsion aqueous droplets in an oil medium together with one uniquely barcoded mRNA-capture bead.

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 disclosure discloses an engineered liposome with cell membrane proteins to reduce melanosome transport and a preparation method thereof, and belongs to the technical field of cosmetics and biomedicine. The present disclosure provides the engineered liposome with cell membrane proteins to reduce melanosome transport and the preparation method thereof, which is easy to operate, requires no large-scale equipment, has few additives, and a preparation process is simple and environmentally friendly. The biomimetic liposome can significantly inhibit melanin transport. The fluorescence intensity of melanosomes in keratinocytes is found to decrease by 3.5-fold in a co-culture test of melanocytes and the keratinocytes, indicating that this biomimetic liposome is very effective in inhibiting accumulation of melanin in skin keratinocytes.

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 emulsions, and more particularly, to multiple emulsions. In one aspect, multiple emulsions are formed by urging a fluid into a channel, e.g., by causing the fluid to enter the channel as a “jet.” Side channels can be used to encapsulate the fluid with a surrounding fluid. In some cases, multiple fluids may flow through a channel collinearly before multiple emulsion droplets are formed. The fluidic channels may also, in certain embodiments, include varying degrees of hydrophilicity or hydrophobicity. As examples, the fluidic channel may be relatively hydrophilic upstream of an intersection (or other region within the channel) and relatively hydrophobic downstream of the intersection, or vice versa. In some cases, the average cross-sectional dimension may change, e.g., at an intersection. For instance, the average cross-sectional dimension may increase at the intersection.

Abstract: The present invention is generally related to systems and methods for producing droplets. The droplets may contain varying species, e.g., for use as a library. In some cases, at least one droplet is used to create a plurality of droplets, using techniques such as flow-focusing techniques. In one set of embodiments, a plurality of droplets, containing varying species, can be divided to form a collection of droplets containing the various species therein. A collection of droplets, according to certain embodiments, may contain various subpopulations of droplets that all contain the same species therein. Such a collection of droplets may be used as a library in some cases, or may be used for other purposes.

Abstract: The present invention is generally related to systems and methods for producing a plurality of droplets. The droplets may contain varying species, e.g., for use as a library. In some cases, the fluidic droplets may be rigidified to form rigidified droplets (e.g., gel droplets). In certain embodiments, the droplets may undergo a phase change (e.g., from rigidified droplets to fluidized droplets), as discussed more herein. In some cases, a species may be added internally to a droplet by exposing the droplet to a fluid comprising a plurality of species.

Abstract: The present disclosure generally relates to sugar reduction in foods and, in some aspects, to enzyme-polymer conjugated particles for food and other applications. Certain aspects of the disclosure are directed to compositions for reducing sugar content and/or producing dietary fiber within food products during or after consumption (e.g., in a subject's gastrointestinal (GI) tract), while maintaining the sweetness and flavor of the sugar in food products upon consumption (e.g., in a subject's mouth). For example, in one set of embodiments, a composition may comprise a particle comprising an enzyme capable of converting a sugar into a relatively non-digestible form (e.g., a polymer), optionally an inhibitor that reversibly inhibits the enzyme from converting the sugar, and optionally an additive capable of associating with the inhibitor. The composition may be used for in situ conversion of sugars upon exposure to an environment condition (e.g., pH and/or temperature) in the GI tract.

Abstract: The present invention generally relates to microfluidic devices. In some aspects, various entities, such as droplets or particles, may be contained within a microfluidic device, e.g., within collection chambers or other locations within the device. In some cases, the entities may be released from such locations, e.g., in a sequential pattern, or an arbitrary pattern. In some cases, the entities may be imaged, reacted, analyzed, etc. while contained within the collection chambers. Other aspects are generally directed to methods of making or using such devices, kits involving such devices, or the like.

Abstract: The present invention generally relates to a controlled fluidic device to develop spatially complex environments to enhance the rate of evolution in cell populations. The method further provides an enhanced understanding in the emergence, for example, drug resistance during cancer chemotherapy.

Abstract: The present invention generally relates to microfluidics and labeled nucleic acids. For example, certain aspects are generally directed to systems and methods for labeling nucleic acids within microfluidic droplets or other compartments, for instance, arising from a cell. In one set of embodiments, particles may be prepared containing oligonucleotides that can be used to determine target nucleic acids, e.g., attached to the surface of the particles. The oligonucleotides may include “barcodes” or unique sequences that can be used to distinguish nucleic acids in a droplet from those in another droplet, for instance, even after the nucleic acids are pooled together or removed from the droplets. Certain embodiments of the invention are generally directed to systems and methods for attaching additional or arbitrary sequences to the nucleic acids within microfluidic droplets or other compartments, e.g.