The methods described herein provide an improved approach for generating monodispersed droplets. Monodispersed droplets may be effectively obtained by using a plurality of particles to trigger the breakup of a jet, which can include, e.g., flowing in a channel of a microfluidic device a first fluid into a second fluid under stable jetting conditions to provide a jet of the first fluid in the second fluid, wherein the first fluid is immiscible with the second fluid; and introducing a plurality of particles into the jet of the first fluid triggering break-up of the jet of the first fluid and encapsulation of the plurality of particles in a plurality of monodispersed droplets of the first fluid in the second fluid.

Some variations provide a device for assembling a plurality of particles into particle assemblies, comprising: (a) a microfluidic droplet-generating region; (b) a first inlet to the droplet-generating region, configured to feed a first fluid containing particles and a solvent for the particles; (c) a second inlet to the droplet-generating region, configured to feed a second fluid that is not fully miscible with the first fluid; (d) a droplet outlet from the droplet-generating region, configured to withdraw droplets of the first fluid dispersed in the second fluid; and (e) a droplet-dissolving region configured to remove solvent from the droplets, thereby forming particle assemblies. Some variations also provide an assembly of nanoparticles, wherein the assembly has a volume from 1 μm.sup.3 to 1 mm.sup.3, a packing fraction from 20% to 100%, and/or an average relative surface roughness less than 1%, wherein the assembly is not disposed on a substrate.

The invention generally relates to methods for quantifying an amount of enzyme molecules. Systems and methods of the invention are provided for measuring an amount of target by forming a plurality of fluid partitions, a subset of which include the target, performing an enzyme-catalyzed reaction in the subset, and detecting the number of partitions in the subset. The amount of target can be determined based on the detected number.

The present invention relates to a microfluidic device, a method for manufacturing a microfluidic device, and a method for provision of double emulsion droplets using a microfluidic device. Furthermore, the present invention relates to an assembly configured to supply pressure to the microfluidic device for provision of double emulsion droplets. Furthermore, the present invention relates to a kit comprising a plurality of microfluidic devices and a plurality of fluids configured for use with the microfluidic device for provision of double emulsion droplets. The microfluidic device comprises a transfer conduit comprising a first transfer conduit part having a first affinity for water; and a collection conduit comprising a first collection conduit part having a second affinity for water being different from the first affinity for water. A well section and a microfluidic section of the microfluidic device are fixedly connected to each other.

The present invention relates to a microfluidic device, a method for manufacturing a microfluidic device, and a method for provision of double emulsion droplets using a microfluidic device. Furthermore, the present invention relates to an assembly configured to supply pressure to the microfluidic device for provision of double emulsion droplets. Furthermore, the present invention relates to a kit comprising a plurality of microfluidic devices and a plurality of fluids configured for use with the microfluidic device for provision of double emulsion droplets. The microfluidic device comprises a transfer conduit comprising a first transfer conduit part having a first affinity for water; and a collection conduit comprising a first collection conduit part having a second affinity for water being different from the first affinity for water. A well section and a microfluidic section of the microfluidic device are fixedly connected to each other.

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.

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.

Disclosed herein are microfluidic devices and systems for amplifying and detecting a target polynucleotide, comprising: one or more wells for receiving one or more substrates; a droplet generation channel in fluid communication with the one or more wells, wherein the microfluidic channel is adapted to generate droplets; and a chamber in fluid communication with the droplet generation channel, and adapted to collect droplets generated by the droplet generation channel, and further adapted to perform nucleic acid amplification in droplets, and further adapted to detect light signal from droplets. Also disclosed are methods of using the same.

A flow focusing type one-step double emulsion droplet parallel generation device and method. The device comprises a fluid injection module, a liquid droplet generation module, a liquid droplet surface solidification module and a liquid droplet collection module, wherein the fluid injection module is used for conveying fluid of each phase to the liquid droplet generation module; and the liquid droplet generation module comprises a fluid distribution functional area, a liquid droplet preparation functional area and an auxiliary functional arca, wherein the liquid droplet distribution functional area is used for conveying the fluid of each phase into a channel of the fluid of each phase corresponding to the liquid droplet preparation functional area, and the fluid of each phase is gathered at the same point in a flow focusing structure and then is broken, and a fluid of an outer phase covers the fluid of the middle phase.

A flow focusing type one-step double emulsion droplet parallel generation device and method. The device comprises a fluid injection module, a liquid droplet generation module, a liquid droplet surface solidification module and a liquid droplet collection module, wherein the fluid injection module is used for conveying fluid of each phase to the liquid droplet generation module; and the liquid droplet generation module comprises a fluid distribution functional area, a liquid droplet preparation functional area and an auxiliary functional arca, wherein the liquid droplet distribution functional area is used for conveying the fluid of each phase into a channel of the fluid of each phase corresponding to the liquid droplet preparation functional area, and the fluid of each phase is gathered at the same point in a flow focusing structure and then is broken, and a fluid of an outer phase covers the fluid of the middle phase.