Methods for selectively adding one or more reagents are provided. In certain aspects, the methods include selectively merging one or more droplets of a plurality of droplets with one or more droplets of a plurality of reagent droplets based on detection of a property. Systems, devices and kits for practicing the subject methods are also provided. The subject disclosure may find use in a wide variety of applications, such as increasing the accuracy and/or efficiency of single-cell sequencing, detection of cancer or other diseases, monitoring disease progression, analyzing the DNA or RNA content of cells, and other applications in which it is desired to detect and/or quantify specific target cells.

An integrated semiconductor device for manipulating and processing bio-entity samples and methods are described. The device includes a lower substrate, at least one optical signal conduit disposed on the lower substrate, at least one cap bonding pad disposed on the lower substrate, a cap configured to form a capped area, and disposed on the at least one cap bonding pad, a fluidic channel, wherein a first side of the fluidic channel is formed on the lower substrate and a second side of the fluidic channel is formed on the cap, a photosensor array coupled to sensor control circuitry, and logic circuitry coupled to the fluidic control circuitry, and the sensor control circuitry.

An integrated semiconductor device for manipulating and processing bio-entity samples and methods are described. The device includes a lower substrate, at least one optical signal conduit disposed on the lower substrate, at least one cap bonding pad disposed on the lower substrate, a cap configured to form a capped area, and disposed on the at least one cap bonding pad, a fluidic channel, wherein a first side of the fluidic channel is formed on the lower substrate and a second side of the fluidic channel is formed on the cap, a photosensor array coupled to sensor control circuitry, and logic circuitry coupled to the fluidic control circuitry, and the sensor control circuitry.

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.

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.

Methods and systems for creating emulsions are described. Also described are the emulsions created by the methods or with the systems.

Microfluidic pumps are provided that use electrowetting to manipulate the location of one or more droplets of a working fluid (e.g., water) in order to pump tears, blood, laboratory samples, carrier fluid, or some other payload fluid. The working fluid is separated from the payload fluid by one or more droplets of an isolating fluid that is immiscible with the working fluid. The working fluid is manipulated via electrowetting, by applying voltages to two or more electrodes, to repeatedly move back and forth. Forces, pressures, and/or fluid flows exerted by the working fluid are coupled to the payload fluid via the droplet(s) of isolation fluid and reed valves, diffuser nozzles, or other varieties of valve can act as flow-rectifying elements to convert the coupled forces into a net flow of the payload fluid through the pump.

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.

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.

Disclosed are devices and methods useful for confined-channel digital microfluidics that combine high-throughput droplet generators with digital microfluidic for droplet manipulation. The present disclosure also provides an off-chip sensing system for droplet tracking.