Abstract:
The present invention relates to droplet-based particle sorting. According to one embodiment, a droplet microactuator is provided and includes: (a) a suspension of particles; and (b) electrodes arranged for conducting droplet operations using droplets comprising particles. A method of transporting a particle is also provided, wherein the method includes providing a droplet comprising the particle and transporting the droplet on a droplet microactuator.
Abstract:
During droplet operations in a droplet actuator, bubbles often form in the filler fluid in the droplet operations gap and interrupt droplet operations. The present invention provides methods and systems for performing droplet operations on a droplet in a droplet actuator comprising maintaining substantially consistent contact between the droplet and an electrical ground while conducting multiple droplet operations on the droplet in the droplet operations gap and/or reducing the accumulation of electrical charges in the droplet operations gap during multiple droplet operations. The methods and systems reduce or eliminate bubble formation in the filler fluid of the droplet operations gap, thereby permitting completion of multiple droplet operations without interruption by bubble formation in the filler fluid in the droplet operations gap.
Abstract:
The present invention relates to droplet-based particle sorting. According to one embodiment, a method of providing a droplet comprising a single cell is provided, wherein the method includes providing a droplet comprising a suspension of cells on an electrowetting droplet actuator surrounded by an oil medium, dispensing from the droplet to provide a dispensed droplet, determining whether the dispensed droplet on the electrowetting droplet actuator comprises a single cell, and sorting the dispensed droplet on the electrowetting droplet actuator based on the results of the determining step using electrowetting-mediated droplet operations.
Abstract:
The invention provides droplet actuators and droplet actuator techniques. Among other things, the droplet actuators and methods are useful for manipulating beads on a droplet actuator, such as conducting droplet operations using bead-containing droplets on a droplet actuator. For example, beads may be manipulated on a droplet actuator in the context of executing a sample preparation protocol and/or an assay protocol. An output of the methods of the invention may be beads prepared for execution of an assay protocol. Another output of the methods of the invention may be results of an assay protocol executed using beads. Among the methods described herein are methods of concentrating beads in droplets, methods of washing beads, methods of suspending beads, methods of separating beads, methods of localizing beads within a droplet, methods of forming emulsions in which droplets include beads, methods of loading beads into a droplet operations gap of a droplet actuator, methods of organizing beads in a monolayer, and methods of capturing, trapping or restraining beads.
Abstract:
A method of loading a droplet actuator is provided. In one embodiment, the method may include, providing: a droplet actuator loaded with a filler fluid; a reservoir comprising a droplet fluid; and a fluid path extending from the reservoir into the droplet actuator; and forcing filler fluid from one locus in the droplet actuator to another locus in the droplet actuator; or out of the droplet actuator; thereby causing droplet fluid to flow through the fluid path and into the droplet actuator.
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, 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:
Methods comprising measuring the impedance of the electrode produced by the excitation signal, wherein the impedance indicates presence of liquid at the electrode are disclosed. Computer readable mediums storing processor executable instructions for performing the method, and systems are also disclosed. The systems comprise a processor, memory and code stored in the memory that when executed cause the processor at least to: receive an output voltage signal, superimpose an excitation signal onto the output voltage signal to produce a superimposed signal, connect the superimposed signal to an electrode in a droplet actuator, suppress the output voltage signal, when detecting an impedance of the electrode, and measure the impedance of the electrode produced by the excitation signal, wherein the impedance indicates presence of liquid 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 invention provides a method of dispersing or circulating magnetically responsive beads within a droplet in a droplet actuator. The invention, in one embodiment, makes use of a droplet actuator with a plurality of droplet operations electrodes configured to transport the droplet, and a magnetic field present at a portion of the plurality of droplet operations electrodes. A bead-containing droplet is provided on the droplet actuator in the presence of the uniform magnetic field. Beads are circulated in the droplet during incubation by conducting droplet operations on the droplet within a uniform region of the magnate field. Other embodiments are also provided.