The present invention relates to a device and a method for dynamic fractionation of a dispersed phase in a fluid. The device comprises a fractionation channel and from a first to a third injection ports. A first and a second confining fluids are injectable through the first and second injection ports, respectively. An elution fluid for transporting the dispersed phase is injectable into the channel through a third injection port which is arranged between the first and second injection ports. An end portion of the channel comprises from a first to a third terminal portion respectively arranged in correspondence to the first to the third injection ports and having a geometry such that the first and second confining fluids respectively have a first and second predefined flow rate and the elution fluid have a third predefined flow rate which is larger than the first and second predefined flow rates.

Apparatus for extracting organic analytes from a sample comprising a first compressed gas source connected to valving and a sample extraction cell connected to the valving. A pressure regulator is connected to the extraction cell outlet to the pressure regulator. The pressure regulator blocks fluid flow when the pressure at the pressure regulator inlet is below a predetermined pressure and permits fluid flow when above said predetermined pressure. The apparatus is free of operative association with a mechanical pump or with a compressed gas source other than the compressed gas source. An extraction method for using the above apparatus is described.

A flow control system for a microfluidic device includes: a plurality of fluid flow controllers, each fluid flow controller associated with a respective microfluidic device inlet of the microfluidic device, and wherein each fluid flow controller includes: a controller inlet for receiving a fluid flow, a first fluid channel and a second fluid channel, each of the first and the second fluid channels having a first end connected to the controller inlet and a second end connected to a supply channel, and a valve for selecting the fluid flow to be passed from the controller inlet to the first fluid channel or to the second fluid channel, wherein the first fluid channel has a first flow resistance that smaller than a second flow resistance of the second fluid channel.

A lateral flow diagnostic assay device is defined by a substrate having a top surface that further includes a sample addition zone for receiving a sample, a transport and reaction zone, and a wicking zone. Each of the sample addition zone, reaction and transport zone and wicking zone are disposed on the top surface of the substrate and fluidically interconnected by means that permit lateral capillary flow along at least one fluid flow path from the sample addition zone to the wicking zone. The assay device further includes a capillary vent disposed in relation to the wicking zone, the capillary vent having an overall length and cross sectional area that creates a backpressure so as to control the flow rate of a sample applied to the assay device.

Systems and methods are provided for determining a velocity or an inflation rate of a droplet in a microfluidic channel. The droplet is exposed to two or more temporally separated flashes of light, each flash including light of one wavelength band, and imaged using a detector configured to distinguish light in the wavelength bands. Two or more images of the droplet are acquired, each corresponding to one of the flashes, and all within a single video frame or photographic exposure. The images can be processed separately and the position or size of the droplet in each image is calculated. A velocity or inflation rate is then determined by dividing the change in position or size by the amount of time allowed to pass between the flashes.

A switchable hydrophilic surface is created by attaching electrochemically switchable hydrophilicity polymers to the surface of a microelectrode array. Ferrocene polymers are one example of electrochemically switchable hydrophilicity polymers. Activation of electrodes in the microelectrode array changes the oxidation state of metal ions which switches the polymers between hydrophobic and hydrophilic conformations. Selective activation of electrodes can create patterns of wettability on the microelectrode array that may be varied in real time. The switchable hydrophilic surface may be used to control solid-phase synthesis of polymers. Growing polymers may be selectively extended at locations on the microelectrode array that are hydrophilic. The pattern of hydrophobic and hydrophilic regions can be changed during sequential rounds of synthesis to create a variety of different polymers at different locations on the surface of the microelectrode array.

Disclosed herein are solvent reservoir systems for steady flow delivery and simultaneous monitoring of solvent level and solvent density within the solvent reservoir systems and methods for monitoring the solvent reservoir systems and providing feedback to a user or adjusting the systems in response to the monitored characteristics.

Methods and apparatus for detecting, quantifying, enriching, and/or separating bacterial species in fluid sample are provided. The fluid sample is provided as input to a microfluidic passage of a microfluidic device, wherein the microfluidic device comprises at least one electrode disposed adjacent to the microfluidic passage. The at least one electrode is activated to capture bacteria in the sample using dielectrophoresis, wherein the capture efficiency of bacteria is at least 99%.

The present invention provides a microfluidic circuit for generating uniform droplets despite fluctuations in pressure, and manufacturing methods and uses thereof. Said circuit comprises microfluidic channels for carrying a continuous phase and a dispersed phase. In one embodiment, the ratio of the flow resistance of the dispersed phase to that of the continuous phase is equal to the ratio of the flow rate of the continuous phase to that of the dispersed phase. In one embodiment, the present microfluidic circuit comprises two features to achieve the desired ratio of flow resistance and flow rate of the dispersed phase and continuous phase: (a) using a single pressure source which applies identical pressure to the inlets of the upstream channels carrying the two phases, and (b) the flow resistance of the dispersed phase and continuous phase is much higher than the flow resistance of the downstream channel so that the flow resistance of the downstream channel become negligible.

Devices and methods for controlling collection of liquid sample are described. In an example, a microfluidic device can include an analytical device and an actuator. The actuator can be connected to the analytical device. The actuator can be operable to absorb fluid. The actuator can guide the absorbed fluid to an input layer of the analytical device. The actuator can deform in response to an occurrence of an absorption condition. A degree of deformation of the actuator indicates a volume of fluid collected by the analytical device.