Abstract: The present disclosure provides methods, devices, systems and compositions for detecting nucleic acids in polymerase chain reaction assays, such as droplet digital polymerase chain reaction (ddPCR) assays. The present disclosure provides methods, devices, systems and compositions for detecting nucleic acids in ddPCR assays using intercalating dyes. A dual surfactant system with at least one fluorosurfactant and at least one non-ionic non-fluorosurfactant may be employed for droplet generation and nucleic acid detection.

Abstract: System, including methods, apparatus, and kits, for forming emulsions. In an exemplary method of generating droplets, a device may be selected that includes a plurality of emulsion-formation units each including a sample well, a continuous-phase well, a droplet well, and a channel network that fluidically interconnects the wells and creates a droplet-generation region. A discrete volume of sample-containing fluid may be placed into the sample well of each emulsion-formation unit, and a discrete volume of continuous-phase fluid into the continuous-phase well of each emulsion-formation unit. Pressure may be applied to the device with a fluidics assembly after the step of placing, such that the plurality of emulsion-formation units generate droplets in parallel with one another. A pressure signal may be detected from the fluidics assembly. Application of the pressure may be stopped when the pressure signal indicates that a sample well is empty.

Abstract: System, including methods and compositions, for making and using emulsions that include a silicone oil and a silicone surfactant. The emulsions may include aqueous droplets disposed in a continuous phase that includes a silicone oil and a silicone surfactant. The aqueous droplets may contain an analyte, optionally at partial occupancy, and/or a luminescent (e.g., photoluminescent) reporter. An assay of the analyte may be performed with the droplets. In some cases, signals may be detected from the droplets, and a characteristic of the analyte, such as an analyte level or activity, may be determined based on the signals.

Abstract: System, including methods, apparatus, compositions, and kits, for making and using a stabilized emulsion. A method of generating a stabilized emulsion is provided. In the method, an aqueous phase may be provided. The aqueous phase may include an effective concentration of one or more skin-forming proteins. An emulsion may be formed. The emulsion may include droplets of a dispersed phase disposed in a continuous phase, with the aqueous phase being the continuous phase or the dispersed phase. The emulsion may be heated to create an interfacial skin between each droplet and the continuous phase, to transform the droplets into capsules.

Abstract: System, including methods, apparatus, and kits, for forming emulsions. In an exemplary method of generating droplets, a device may be selected that includes a plurality of emulsion-formation units each including a sample well, a continuous-phase well, a droplet well, and a channel network that fluidically interconnects the wells and creates a droplet-generation region. A discrete volume of sample-containing fluid may be placed into the sample well of each emulsion-formation unit, and a discrete volume of continuous-phase fluid into the continuous-phase well of each emulsion-formation unit. Pressure may be applied to the device with a fluidics assembly after the step of placing, such that the plurality of emulsion-formation units generate droplets in parallel with one another. A pressure signal may be detected from the fluidics assembly. Application of the pressure may be stopped when the pressure signal indicates that a sample well is empty.

Abstract: Devices and methods for generating droplets. An exemplary device comprises a substantially planar base portion including a bottom surface having a plurality of microfluidic channels formed therein as recessed regions of the bottom surface. The device also comprises a plurality of protrusions projecting from a top surface of the base portion and each formed integrally with the base portion. The device further comprises a sample well, a carrier well, and a droplet well. Each well has an upper portion created by one of the protrusions. A cover layer is attached to the bottom surface of the base portion and seals a bottom side of each microfluidic channel.

Abstract: Methods of generating droplets. In an exemplary method, a device including a sample well, a carrier well, a droplet well, and a plurality of microfluidic channels is selected. The microfluidic channels include a first channel, a second channel, and a third channel. A discrete volume of sample-containing fluid is placed into the sample well, and a discrete volume of carrier fluid is placed into the carrier well. A pressure differential is created after placing the discrete volumes, to cause fluid flow. Sample-containing fluid flows from the sample well to a droplet-generation region of the device via the first channel. Carrier fluid flows from the carrier well to the droplet-generation region via the second channel. Sample-containing droplets and carrier fluid flow from the droplet-generation region to the droplet well via the third channel.

Abstract: Methods of making a droplet-generating device. In an exemplary method, an upper member is injection molded. The upper member includes a bottom surface and also includes a first microfluidic channel, a second microfluidic channel, and a third microfluidic channel each formed in the bottom surface. The upper member has a plurality of openings each extending completely through the upper member from the bottom surface and creating a side wall region of a sample well, a carrier well, and a droplet well. A cover layer is attached to the bottom surface of the upper member, such that the cover layer seals a bottom side of each microfluidic channel. The microfluidic channels meet one another to create a droplet-generation region. The sample well, the carrier well, and the droplet well are connected to the droplet-generation region via the first, second, and third microfluidic channels, respectively.

Abstract: System, including methods, apparatus, and kits, for forming and concentrating emulsions. An exemplary system may comprise a device including a sample well configured to receive sample-containing fluid, a continuous-phase well configured to receive continuous-phase fluid, a droplet well, and a channel network interconnecting the wells. The system also may comprise an instrument configured to operatively receive the device and to create (i) a first pressure differential to produce an emulsion collected in the droplet well and (ii) a second pressure differential to decrease a volume fraction of continuous-phase fluid in the emulsion, after the emulsion has been collected in the droplet well, by selectively driving continuous-phase fluid, relative to sample-containing droplets, from the droplet well.

Abstract: System, including methods, apparatus, and kits, for forming emulsions. An exemplary system may comprise a device including a sample well configured to receive sample-containing fluid, a continuous-phase well configured to receive continuous-phase fluid, and a droplet well. The device also may include a channel network having a first channel, a second channel, and a third channel that meet one another in a droplet-generation region. The system also may comprise a holder for the device. The system further may comprise an instrument configured to operatively receive an assembly including the device and the holder and to drive sample-containing fluid from the sample well to the droplet-generation region via the first channel, continuous-phase fluid from the continuous-phase well to the droplet-generation region via the second channel, and sample-containing droplets from the droplet-generation region to the droplet well via the third channel.

Abstract: System, including methods, apparatus, compositions, and kits, for making and using a stabilized emulsion. A method of generating a stabilized emulsion is provided. In the method, an aqueous phase may be provided. The aqueous phase may include an effective concentration of one or more skin-forming proteins. An emulsion may be formed. The emulsion may include droplets of a dispersed phase disposed in a continuous phase, with the aqueous phase being the continuous phase or the dispersed phase. The emulsion may be heated to create an interfacial skin between each droplet and the continuous phase, to transform the droplets into capsules.

Abstract: System, including methods, apparatus, and kits, for forming and concentrating emulsions. An exemplary system may comprise a device including a sample well configured to receive sample-containing fluid, a continuous-phase well configured to receive continuous-phase fluid, a droplet well, and a channel network interconnecting the wells. The system also may comprise an instrument configured to operatively receive the device and to create (i) a first pressure differential to produce an emulsion collected in the droplet well and (ii) a second pressure differential to decrease a volume fraction of continuous-phase fluid in the emulsion, after the emulsion has been collected in the droplet well, by selectively driving continuous-phase fluid, relative to sample-containing droplets, from the droplet well.

Abstract: System, including methods, apparatus, and kits, for forming emulsions. An exemplary system may comprise a device including a sample well configured to receive sample-containing fluid, a continuous-phase well configured to receive continuous-phase fluid, and a droplet well. The device also may include a channel network having a first channel, a second channel, and a third channel that meet one another in a droplet-generation region. The system also may comprise a holder for the device. The system further may comprise an instrument configured to operatively receive an assembly including the device and the holder and to drive sample-containing fluid from the sample well to the droplet-generation region via the first channel, continuous-phase fluid from the continuous-phase well to the droplet-generation region via the second channel, and sample-containing droplets from the droplet-generation region to the droplet well via the third channel.

Abstract: A method of rapid, genome and proteome based identification of unknown pathogenic or non-pathogenic organisms in a complex sample. The entire sample is analyzed by creating millions of emulsion encapsulated microdroplets, each containing a single pathogenic or non-pathogenic organism sized particle and appropriate reagents for amplification. Following amplification, the amplified product is analyzed.

Abstract: System, including methods and apparatus, for performing droplet-based assays that are controlled and/or calibrated using signals detected from droplets.

Abstract: Method of transporting droplets for detection. An emulsion disposed in a container and including droplets may be provided. Contact may be created between a tip and the emulsion. The tip may be connected to an examination region and may include an outer tube and an inner tube. The outer tube may form a first open end and surround an enclosed portion of the inner tube. The inner tube may extend out of the first open end to create a projecting portion forming a second open end below the first open end. Droplets of the emulsion may be loaded into the inner tube via the second open end. Loaded droplets may be moved from the inner tube to the examination region. Fluid may be dispensed onto the projecting portion of the inner tube from the first open end formed by the outer tube.

Abstract: System, including methods, apparatus, and compositions, for performing a multiplexed digital assay on a greater number of targets through combinatorial use of signals.

Abstract: Provided herein are improved methods, compositions, and kits for analysis of nucleic acids. The improved methods, compositions, and kits can enable copy number estimation of a nucleic acid in a sample. Also provided herein are methods, compositions, and kits for determining the linkage of two or more copies of a target nucleic acid in a sample (e.g. whether the two or more copies are on the same chromosome or different chromosomes) or for phasing alleles.

Abstract: System, including methods, apparatus, compositions, and kits, for the mixing of small volumes of fluid by coalescence of multiple emulsions.

Abstract: System, including methods, apparatus, and compositions, for performing a multiplexed digital assay on a greater number of targets through combinatorial use of signals.