A microfluidic device may include a valve located between a liquid source and a liquid receiver. The valve may include a channel connecting the liquid source to the liquid receiver, a heater within the channel, and a pinch point in the channel between the heater and the liquid receiver. The microfluidic device may include a controller to activate the heater so as to form a bubble sized so as to be captured by the pinch point in the channel to occlude the channel.

A capsule is disclosed which includes a flexible outer shell capable of transforming into an asymmetric shape; an internal medium encapsulated by the outer shell, the medium including a plurality of magnetic particles, wherein the magnetic particles can move in response to an applied magnetic field. A valve system includes an in-line valve sized to fit within a flow channel including a capsule having a flexible outer shell containing an internal medium encapsulated by the outer shell, the medium including a plurality of magnetic particles; and a magnetic field source disposed about the exterior wall of the channel.

The present technology provides for a heater substrate that contains networks of heater elements configured to controllably and selectively deliver heat to one or more PCR reaction chambers in a microfluidic substrate with which the heater substrate makes contact. In exemplary embodiments, the heater substrate can deliver heat to 12, 24, 48, or 96 chambers independently of one another, or simultaneously. The heater substrate is located in a heater unit that may be introduced into a diagnostic apparatus that can receive and position a microfluidic substrate, such as in a cartridge, in contact with the heater unit, receive one or more polynucleotide containing samples into one or more lanes in the microfluidic substrate, and cause amplification of the polynucleotides to occur, and detect presence of absence of specified polynucleotides in the amplified samples.

A microfluidic device includes a microchannel having an interior bounded by a side wall, an inlet, a switching region, and a plurality of outlet channels downstream of the switching region. The microchannel is formed in a microfluidic chip substrate and configured to accommodate a flow of liquid through the microchannel. The microfluidic device includes a valve operatively coupled to the switching region comprising a sealed reservoir. A side passage extends between the reservoir and the interior of the microchannel via an aperture in the side wall and is configured to accommodate a volume of liquid between the interior of the microchannel and the reservoir. The microfluidic device includes an actuator integrated into the microfluidic chip and configured to increase an internal pressure of the reservoir and move at least a portion of the volume of the liquid from the side passage into the microchannel to deflect a portion of the liquid flowing through the microchannel.

Methods and systems for processing polynucleotides (e.g., DNA) are disclosed. A processing region includes one or more surfaces (e.g., particle surfaces) modified with ligands that retain polynucleotides under a first set of conditions (e.g., temperature and pH) and release the polynucleotides under a second set of conditions (e.g., higher temperature and/or more basic pH). The processing region can be used to, for example, concentrate polynucleotides of a sample and/or separate inhibitors of amplification reactions from the polynucleotides. Microfluidic devices with a processing region are disclosed.

A method and apparatus for sorting particles moving through a closed channel system of capillary size comprises actuators and chambers for selectively generating a pressure pulse to separate a particle having a predetermined characteristic from a stream of particles. The particle sorting system may further include a buffer for absorbing the pressure pulse. The particle sorting system may include a plurality of closely coupled sorting modules which are combined to further increase the sorting rate. The particle sorting system may comprise a multi-stage sorting device for serially sorting streams of particles, in order to decrease the error rate.

A microfluidic control apparatus, such as a relief valve, includes a pressure containing housing to contain a fluid within an interior of the pressure containing housing, and a nanotube in fluid communication between the interior of the pressure containing housing and an exterior of the pressure containing housing. The nanotube is used to contain water therein such that, below a predetermined temperature, the water within the nanotube prevents pressure relief through the nanotube from the interior to the exterior of the pressure containing housing, and above the predetermined temperature, the water within the nanotube enables pressure relief through the nanotube from the interior to the exterior of the pressure containing housing.

A method and apparatus for sorting particles moving through a closed channel system of capillary size comprises actuators and chambers for selectively generating a pressure pulse to separate a particle having a predetermined characteristic from a stream of particles. The particle sorting system may further include a buffer for absorbing the pressure pulse. The particle sorting system may include a plurality of closely coupled sorting modules which are combined to further increase the sorting rate. The particle sorting system may comprise a multi-stage sorting device for serially sorting streams of particles, in order to decrease the error rate.

A microfluidic valve may include a firing chamber having an orifice, a first portion of a liquid conduit connected to the firing chamber at a first port, a second portion of the liquid conduit connected to the firing chamber at a second port and a thermal resistor. The thermal resistor is to form a bubble within the firing chamber to expel liquid from the firing chamber through the orifice such that a first meniscus forms across the first port and a second meniscus forms across the second port to interrupt liquid flow between the first portion and the second portion of the liquid conduit.

The present disclosure is drawn to microfluidic chips. The microfluidic chips can include an inflexible material having an elastic modulus of 0.1 gigapascals (GPa) to 450 GPa. A microfluidic channel can be formed within the inflexible material and can connect an inlet and an outlet. A working electrode can be associated with the microfluidic channel and can have a surface area of 1 m.sup.2 to 60,000 m.sup.2 within the microfluidic channel. A bubble support structure can also be formed within the microfluidic channel such that the working electrode is positioned to electrolytically generate a bubble that becomes associated with the bubble support structure.