Described herein are systems relating to a continuous-flow instrument that includes all necessary components for digital droplet quantification without the need to introduce key reagents or collect and transfer droplets between stages of instrument operation. Digital quantification can proceed without any additional fluid or consumable handling and without exposing fluids to risk of external contamination.

Various aspects of the present invention relate to the control and manipulation of fluidic species, for example, in microfluidic systems. In one aspect, the invention relates to systems and methods for making droplets of fluid surrounded by a liquid, using, for example, electric fields, mechanical alterations, the addition of an intervening fluid, etc. In some cases, the droplets may each have a substantially uniform number of entities therein. For example, 95% or more of the droplets may each contain the same number of entities of a particular species. In another aspect, the invention relates to systems and methods for dividing a fluidic droplet into two droplets, for example, through charge and/or dipole interactions with an electric field. The invention also relates to systems and methods for fusing droplets according to another aspect of the invention, for example, through charge and/or dipole interactions. In some cases, the fusion of the droplets may initiate or determine a reaction. In a related aspect of the invention, systems and methods for allowing fluid mixing within droplets to occur are also provided. In still another aspect, the invention relates to systems and methods for sorting droplets, e.g., by causing droplets to move to certain regions within a fluidic system. Examples include using electrical interactions (e.g., charges, dipoles, etc.) or mechanical systems (e.g., fluid displacement) to sort the droplets. In some cases, the fluidic droplets can be sorted at relatively high rates, e.g., at about 10 droplets per second or more. Another aspect of the invention provides the ability to determine droplets, or a component thereof, for example, using fluorescence and/or other optical techniques (e.g., microscopy), or electric sensing techniques such as dielectric sensing.

The present invention provides microfabricated substrates and methods of conducting reactions within these substrates. The reactions occur in plugs transported in the flow of a carrier-fluid.

The present invention provides microfabricated substrates and methods of conducting reactions within these substrates. The reactions occur in plugs transported in the flow of a carrier-fluid.

The present invention generally relates to systems and techniques for manipulating fluids and/or making droplets. In certain aspects, the present invention generally relates to droplet production. The droplets may be formed from fluids from different sources. In one set of embodiments, the present invention is directed to a microfluidic device comprising a plurality of droplet-making units, and/or other fluidic units, which may be substantially identical in some cases. Substantially each of the fluidic units may be in fluidic communication with a different source of a first fluid and a common source of a second fluid, in certain embodiments. In one aspect, substantially the same pressure may be applied to substantially all of the different sources of fluid, which may be used to cause fluid to move from the different sources into the microfluidic device. In some cases, the fluids may interact within the fluidic units, e.g., by reacting, or for the production of droplets within the microfluidic device. In some cases, the droplets may be used, for example, to form a library of droplets.

Described herein are systems relating to a continuous-flow instrument that includes all necessary components for digital droplet quantification without the need to introduce key reagents or collect and transfer droplets between stages of instrument operation. Digital quantification can proceed without any additional fluid or consumable handling and without exposing fluids to risk of external contamination.

A microfluidic synthesis platform includes a microfluidic chip holder that has a computer controlled heating element and cooling element therein. A microfluidic chip is mountable in the microfluidic chip holder. The microfluidic chip is formed by a hydrophobic substrate having patterned thereon a hydrophilic reaction site and a plurality of hydrophilic channels or pathways extending outward from the hydrophilic reaction site and terminating at respective loading sites on the substrate, wherein the hydrophilic channels or pathways are tapered with an increasing width in an inward direction toward the hydrophilic reaction site. A fixture is provided for holding a plurality of non-contact reagent dispensing devices above the microfluidic chip at locations corresponding to the loading sites of the plurality of hydrophilic channels or pathways, the fixture further holding a moveable collection tube disposed above the hydrophilic reaction site of the microfluidic chip for removing droplets containing reaction products.

Methods for selectively combining discrete entities including, e.g. cells, reagents, drugs, hydrogels, extracellular matrices beads, particles, biological materials, media, or a combination thereof, are provided. In certain aspects, the methods include sorting a plurality of discrete entities and trapping two or more discrete entities for a time sufficient for the two or more discrete entities to combine to form a combined discrete entity. In certain aspects, the methods include making the plurality of discrete entities. In certain aspects, the methods include detecting or analyzing the discrete entities, e.g. via optical detection. In certain aspects, the methods include manipulating or analyzing the combined discrete entity or a component therein, e.g. imaging, sequencing, culturing, e.g., three-dimensional culturing, and measuring cell-cell interactions. Systems and devices for practicing the subject methods are also provided.

This invention generally relates to systems and methods for the formation and/or control of fluidic species, and articles produced by such systems and methods. In some cases, the invention involves unique fluid channels, systems, controls, and/or restrictions, and combinations thereof. In certain embodiments, the invention allows fluidic streams (which can be continuous or discontinuous, i.e., droplets) to be formed and/or combined, at a variety of scales, including microfluidic scales. In one set of embodiments, a fluidic stream may be produced from a channel, where a cross-sectional dimension of the fluidic stream is smaller than that of the channel, for example, through the use of structural elements, other fluids, and/or applied external fields, etc. In some cases, a Taylor cone may be produced. In another set of embodiments, a fluidic stream may be manipulated in some fashion, for example, to create tubes (which may be hollow or solid), droplets, nested tubes or droplets, arrays of tubes or droplets, meshes of tubes, etc. In some cases, droplets produced using certain embodiments of the invention may be charged or substantially charged, which may allow their further manipulation, for instance, using applied external fields. Non-limiting examples of such manipulations include producing charged droplets, coalescing droplets (especially at the microscale), synchronizing droplet formation, aligning molecules within the droplet, etc. In some cases, the droplets and/or the fluidic streams may include colloids, cells, therapeutic agents, and the like.

The present invention provides microfabricated substrates and methods of conducting reactions within these substrates. The reactions occur in plugs transported in the flow of a carrier-fluid.