Abstract: Methods of improving accuracy of droplet metering using at least one on-actuator reservoir as the fluid input. In some embodiments, the on-actuator reservoir that is used for metering droplets includes a loading port, a liquid storage zone, a droplet metering zone, and a droplet dispensing zone. The on-actuator reservoirs are designed to prevent liquid flow-back into the loading port and to prevent liquid from flooding into the droplet operations gap in the dispensing zone.

Abstract: Provided herein are methods of splitting droplets containing magnetically responsive beads in a droplet actuator. A droplet actuator having a plurality of droplet operations electrodes configured to transport the droplet, and a magnetic field present at the droplet operations electrodes, is provided. The magnetically responsive beads in the droplet are immobilized using the magnetic field and the plurality of droplet operations electrodes are used to split the droplet into first and second droplets while the magnetically responsive beads remain substantially immobilized.

Abstract: Methods are provided for separating magnetically responsive beads from a droplet in a droplet actuator. Droplet operations electrodes and a magnet are arranged in a droplet actuator to manipulate a bead-containing droplet and position it relative to a magnetic field region that attracts the magnetically responsive beads. The droplet operations electrodes are operated to control the droplet shape and transport it away from the magnetic field region to form a concentration of beads in the droplet. The continued transport of the droplet away from the magnetic field causes the concentration of beads to break away from the droplet to yield a small, concentrated bead-containing droplet immobilized by the magnet.

Abstract: The present invention is directed to methods of improving accuracy of droplet metering using at least one on-actuator reservoir as the fluid input. In some embodiments, the on-actuator reservoir that is used for metering droplets includes a loading port, a liquid storage zone, a droplet metering zone, and a droplet dispensing zone. The on-actuator reservoirs are designed to prevent liquid flow-back into the loading port and to prevent liquid from flooding into the droplet operations gap in the dispensing zone.

Abstract: The present invention relates to droplet-based surface modification and washing. According to one embodiment, a method of splitting a droplet is provided, the method including providing a droplet microactuator including a droplet including one or more beads and immobilizing at least one of the one or more beads. The method further includes conducting one or more droplet operations to divide the droplet to yield a set of droplets including a droplet including the one or more immobilized beads and a droplet substantially lacking the one or more immobilized beads.

Abstract: Provided herein are methods of splitting droplets containing magnetically responsive beads in a droplet actuator. A droplet actuator having a plurality of droplet operations electrodes configured to transport the droplet, and a magnetic field present at the droplet operations electrodes, is provided. The magnetically responsive beads in the droplet are immobilized using the magnetic field and the plurality of droplet operations electrodes are used to split the droplet into first and second droplets while the magnetically responsive beads remain substantially immobilized.

Abstract: The present invention is directed to methods of improving accuracy of droplet metering using at least one on-actuator reservoir as the fluid input. In some embodiments, the on-actuator reservoir that is used for metering droplets includes a loading port, a liquid storage zone, a droplet metering zone, and a droplet dispensing zone. The on-actuator reservoirs are designed to prevent liquid flow-back into the loading port and to prevent liquid from flooding into the droplet operations gap in the dispensing zone.

Abstract: Aspects of embodiments may include methods for automated enzymatic detection of glucose-6-phosphate dehydrogenase (G6PD) activity. Aspects of embodiments may include methods for enzymatic detection of G6PD activity in droplets in oil. Aspects of embodiments may include a system including a droplet actuator. Aspects of embodiments may include a treatment method.

Abstract: Methods are provided for separating magnetically responsive beads from a droplet in a droplet actuator. Droplet operations electrodes and a magnet are arranged in a droplet actuator to manipulate a bead-containing droplet and position it relative to a magnetic field region that attracts the magnetically responsive beads. The droplet operations electrodes are operated to control the droplet shape and transport it away from the magnetic field region to form a concentration of beads in the droplet. The continued transport of the droplet away from the magnetic field causes the concentration of beads to break away from the droplet to yield a small, concentrated bead-containing droplet immobilized by the magnet.

Abstract: A method comprising effecting a change in a shape of a droplet, wherein the droplet is disposed over a substrate in sensing proximity to a sensor and the droplet has a starting surface area exposed to the sensor; and producing an expanded surface area of the droplet in the sensing proximity exposed to the sensor, wherein the expanded surface area exposed to the sensor is greater than the starting surface area exposed to the sensor.

Abstract: A method of providing a droplet in contact with a magnetically responsive bead and having a reduced quantity of a substance.

Abstract: A method, circuit and apparatus for detecting capacitance on a droplet actuator, inter alia, for determining the presence, partial presence or absence of a droplet at an electrode on a droplet actuator by: (a) providing a droplet actuator comprising: (i) a substrate comprising electrodes arranged on the substrate for conducting droplet operations on a surface of the substrate; (ii) a capacitance detection circuit for detecting capacitance at the droplet operations surface at one or more of the electrodes; (b) detecting capacitance at the droplet operations surface at one or more of the electrodes; and (c) determining from the capacitance the presence, partial presence or absence of a droplet at the droplet operations surface at the electrode.

Abstract: The invention provides a method of circulating magnetically responsive beads within a droplet in a droplet actuator. The invention also provides methods for splitting droplets. The invention, in one embodiment, makes use of a droplet actuator with top and bottom substrates, a plurality of magnetic fields respectively present proximate the top and bottom substrates, wherein at least one of the magnet fields is selectively alterable, and a plurality of droplet operations electrodes positioned along at least one of the top and bottom surfaces. A droplet is positioned between the top and bottom surfaces and at least one of the magnetic fields is selectively altered.

Abstract: The present invention is directed to methods of improving accuracy of droplet metering using at least one on-actuator reservoir as the fluid input. In some embodiments, the on-actuator reservoir that is used for metering droplets includes a loading port, a liquid storage zone, a droplet metering zone, and a droplet dispensing zone. The on-actuator reservoirs are designed to prevent liquid flow-back into the loading port and to prevent liquid from flooding into the droplet operations gap in the dispensing zone.

Abstract: The invention relates to bead incubating and washing on a droplet actuator. Methods for incubating magnetically responsive beads that are labeled with primary antibody, a sample (i.e., analyte), and secondary reporter antibodies on a magnet, on and off a magnet, and completely off a magnet are provided. Also provided are methods for washing magnetically responsive beads using shape-assisted merging of droplets. Also provided are methods for shape-mediated splitting, transporting, and dispensing of a sample droplet that contains magnetically responsive beads. The apparatuses and methods of the invention provide for rapid time to result and optimum detection of an analyte in an immunoassay.

Abstract: In one embodiment, a multiplex fluid processing cartridge includes a sample well, a deformable fluid chamber, a mixing well with a mixer disposed therein, a lysis chamber including a lysis mixer, an electrowetting grid for microdroplet manipulation, and electrosensor arrays configured to detect analytes of interest. An instrument for processing the cartridge is configured to receive the cartridge and to selectively apply thermal energy, magnetic force, and electrical connections to one or more discrete locations on the cartridge and is further configured to compress the deformable chamber(s) in a specified sequence.

Abstract: The invention is directed to a droplet actuator device and methods for integrating gel electrophoresis analysis with pre or post-analytical sample handling as well as other molecular analysis processes. Using digital microfluidics technology, the droplet actuator device and methods of the invention provide the ability to perform gel electrophoresis and liquid handling operations on a single integrated device. The integrated liquid handling operations may be used to prepare and deliver samples to the electrophoresis gel, capture and subsequently process products of the electrophoresis gel or perform additional assays on the same sample materials which are analyzed by gel electrophoresis. In one embodiment, one or more molecular assays, such as nucleic acid (e.g., DNA) quantification by real-time PCR, and one or more sample processing operations such as sample dilution is performed on a droplet actuator integrated with an electrophoresis gel.

Abstract: The invention relates to a droplet actuator device and methods for integrated sample preparation and analysis of a biological sample. A droplet actuator device is provided for conducting droplet operations. The droplet actuator device may include a bottom substrate and a top substrate separated from each other to form a gap therebetween; an arrangement of droplet operations electrodes arranged on one or both of the bottom and/or top substrates for conducting droplet operations thereon; a reagent storage layer comprising one or more compartments bound to the top substrate; and one or more openings arranged to provide a fluidic path from the one or more compartments into the gap, upon breach of a breachable seal separating the one or more compartments and openings.

Abstract: The invention provides droplet actuators and droplet actuator cassettes including reagent storage capabilities, as well as methods of making and using the droplet actuators and cassettes. The invention also provides continuous flow channel elements and techniques for using electrodes to manipulate droplets in flowing streams. The invention also discloses methods of separating compounds on a droplet actuator. Various other aspects of the invention are also disclosed.

Abstract: A liquid handling system for supplying liquids to a flow cell (FC). The system may include a droplet actuator cartridge, wherein the droplet actuator and a flow cell are fluidly coupled to, or situated within, a droplet operations gap of the droplet actuator.