The present invention generally relates to systems and methods for the control of fluids and, in some cases, to systems and methods for flowing a fluid into and/or out of other fluids. As examples, fluid may be injected into a droplet contained within a fluidic channel, or a fluid may be injected into a fluidic channel to create a droplet. In some embodiments, electrodes may be used to apply an electric field to one or more fluidic channels, e.g., proximate an intersection of at least two fluidic channels. For instance, a first fluid may be urged into and/or out of a second fluid, facilitated by the electric field. The electric field, in some cases, may disrupt an interface between a first fluid and at least one other fluid. Properties such as the volume, flow rate, etc. of a first fluid being urged into and/or out of a second fluid can be controlled by controlling various properties of the fluid and/or a fluidic droplet, for example curvature of the fluidic droplet, and/or controlling the applied electric field.

A method of forming a liquid-liquid mixing phase channel group, which has the steps of: ejecting the first liquid as droplets into the phase of the second liquid in a two-liquid phase system in which two immiscible liquids oppose each other at an interface; incorporating the droplets of the first liquid into the phase of the first liquid, accompanied by the second liquid around the first liquid by allowing to collide the jet of the droplets with the interface; and forming a continuously connected microfluidic channel group in which the space between the layered droplets of the first liquid are filled with the second liquid in the liquid-liquid mixing phase that grows from the interface as a starting point.

The invention describes a method for isolating one or more genetic elements encoding a gene product having a desired activity, comprising the steps of: (a) compartmentalising genetic elements into microcapsules; and (b) sorting the genetic elements which express the gene product having the desired activity; wherein at least one step is under microfluidic control. The invention enables the in vitro evolution of nucleic acids and proteins by repeated mutagenesis and iterative applications of the method of the invention.

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.

Provided herein is a first fluid dispersed in a second fluid to form an emulsion of micro-droplets having an average droplet size and having a droplet size distribution around the average droplet size and below a maximum droplet size. The micro-droplets will lose their solvent to transform to micro-spheres exhibiting a particle size distribution around an average particle size and substantially below a maximum allowable particle size. The micro-spheres are subjected to a micro-filter having a relatively narrow pore size distribution around an average pore size, which average pore size is between the average particle size and the maximum particle size. A filtrate of the micro-filter comprises a majority of the micro-spheres that is substantially void of micro-spheres having a particle size exceeding the maximum allowable particle size.

Provided herein is a first fluid dispersed in a second fluid to form an emulsion of micro-droplets having an average droplet size and having a droplet size distribution around the average droplet size and below a maximum droplet size. The micro-droplets will lose their solvent to transform to micro-spheres exhibiting a particle size distribution around an average particle size and substantially below a maximum allowable particle size. The micro-spheres are subjected to a micro-filter having a relatively narrow pore size distribution around an average pore size, which average pore size is between the average particle size and the maximum particle size. A filtrate of the micro-filter comprises a majority of the micro-spheres that is substantially void of micro-spheres having a particle size exceeding the maximum allowable particle size.

A system for processing a biological sample includes a substrate comprising a plurality of wells and a plurality of flow channels. The system further includes a flow control system comprising a manifold having a plurality of ports configured to fluidically couple to the plurality of wells, and one or more containment structures configured to contain carrier fluid and fluidically couple to the ports. The flow control system further includes a cradle configured to removably receive the substrate. The flow control system is configured to transmit pressure differential, via the manifold, to the plurality of wells so as to cause a plurality of sample volumes held by at least some wells of the plurality of wells to flow through respective flow channels and cause the carrier fluid to flow through the flow channels and form a plurality of droplets of the plurality of sample volumes separated by the carrier fluid.

A system for processing a biological sample can include a droplet generation assembly comprising a plurality of first reservoirs configured to contain an aqueous sample and a plurality of second reservoirs configured to contain a carrier fluid immiscible with the aqueous sample. The plurality of first reservoirs and the plurality of second reservoirs can be arranged to be in respective flow communication in pairs of reservoirs comprising a first reservoir of the plurality of first reservoirs and a second reservoir of the plurality of second reservoirs constituting a plurality of pairs of reservoirs. The droplet generation assembly can further include a flow control system configured to control a pressure in the plurality of pairs of reservoirs so as to generate a flow of a series of volumes of the aqueous sample separated by the carrier fluid. The system can further include a thermocycling system.

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.

The invention describes a method for the synthesis of compounds comprising the steps of: (a) compartmentalising two or more sets of primary compounds into microcapsules; such that a proportion of the microcapsules contains two or more compounds; and (b) forming secondary compounds in the microcapsules by chemical reactions between primary compounds from different sets; wherein one or both of steps (a) and (b) is performed under microfluidic control; preferably electronic microfluidic control The invention further allows for the identification of compounds which bind to a target component of a biochemical system or modulate the activity of the target, and which is co-compartmentalised into the microcapsules.