Abstract: An example self-priming microfluidic structure can include a microfluidic channel including a floor and a ceiling. A channel height is defined as a distance between the floor and the ceiling. A channel height step can be in the floor, or ceiling, or both. The channel height downstream of the channel height step can be greater than the channel height upstream of the channel height step. An interior pillar can be positioned in the microfluidic channel extending from the floor to the ceiling. The interior pillar can include a widening portion at an upstream end of the interior pillar and a tapering portion at a downstream end of the interior pillar. The interior pillar can overlap the channel height step so that the interior pillar is partially upstream of the channel height step and partially downstream of the channel height step.

Abstract: Microfluidic systems are provided for the detection and analysis of cell systems that can include a set of reservoirs, the set of reservoirs including a reagent reservoir and an immiscible fluid reservoir, an incubation region having an inlet and an outlet, a set of independent fluidic networks, the set of independent fluidic networks including a first fluidic network and a second fluidic network that is not fluidically connected to the first fluidic network, wherein the first fluidic network (1) is fed by the set of reservoirs, (2) includes a droplet generator, and (3) connects to the inlet of the incubation region, and wherein the second fluidic network is connected to the outlet of the incubation region.

Abstract: A disposable microfluidic cassette can include a substrate and an engagement feature associated with the substrate to removably join the cassette with a cassette-receiver of an analytical system. A microfluidic network can be carried by the substrate. The microfluidic network can include a fluid inlet, a fluid outlet, and a sample manipulation portion fluidly coupling the fluid inlet to the fluid outlet. An ejector can be associated with the microfluidic network to move fluid out of the disposable microfluidic cassette via the fluid outlet.

Abstract: In one example in accordance with the present disclosure, a fluorescence detection system is described. The fluorescence detection system includes a microfluidic chamber to receive a sample containing a compound to be detected. An illumination system provides an excitation light to excite fluorophores in the microfluidic chamber. An outcoupler is disposed between the illumination system and the microfluidic chamber to diffuse the excitation light to fill the microfluidic chamber. The fluorescence detection system also includes a detection system to detect fluorescence generated by the excitation of the fluorophores in the microfluidic chamber.

Abstract: In one example in accordance with the present disclosure, a cell sorting device is described. The cell sorting device includes a microfluidic channel to serially transport individual cells from a volume of cells along a flow path. A sensor disposed in the microfluidic channel distinguishes between a cell to be analyzed and waste fluid. The cell sorting device includes at least two fluid transport devices disposed within the microfluidic channel. The at least two fluid transport devices include a cell ejector to, responsive to detection of a cell to be analyzed, eject the cell to be analyzed from the cell sorting device and a waste transport device to direct the waste fluid to a waste reservoir.

Abstract: A microfluidic device includes a chamber having a floor, a ceiling, and an inlet. The microfluidic device includes pillars extending from the floor to the ceiling of the chamber. Each pillar has a leading surface or corner, a trailing surface or corner opposite the leading surface or corner, and trailing side surfaces adjoining the trailing surface or corner. Each pillar is oriented along a corresponding ray intersecting the leading surface or corner and the trailing surface or corner. Adjacent pillars have a turn angle between the corresponding rays of the adjacent pillars, and each pillar has a pillar angle between the trailing side surfaces thereof. The turn and pillar angles are based on a fluidic contact angle to promote fluid flow from the inlet throughout the chamber during priming without fluidic pinning.

Abstract: In one example in accordance with the present disclosure, a fluorescence detection system is described. The fluorescence detection system includes a microfluidic chamber to receive a sample containing a compound to be detected. The system also includes a light guide, a portion of which is adjacent the microfluidic chamber. The light guide refracts excitation light into the microfluidic chamber to excite fluorophores in the microfluidic chamber. The light guide has total internal reflection in those portions that are not adjacent the microfluidic chamber. The fluorescence detection system also includes a heating element to trigger a reaction in the microfluidic chamber, an illumination source to provide the excitation, and a detection system to detect fluorescence generated by the excitation of the fluorophores in the microfluidic chamber.

Abstract: Apparatuses may be used for nucleic acid amplification. An example apparatus may include an amplification chamber to contain a biochemical reaction associated with amplification of a biologic sample. The biologic sample may include a nucleic acid. The apparatus may also include a heater thermally coupled to the amplification chamber. The apparatus may also include a thermally conductive substrate in contact with the heater and including a liquid coolant passage to pass a liquid coolant through the thermally conductive substrate.

Abstract: An example device includes an array of sensor modules. A sensor module includes a body to be positioned in alignment with a planar target, a light source coupled to the body to emit light to the planar target along a source optical path, and a plurality of light sensors coupled to the body. Each light sensor is to sense a different wavelength of light received from the planar target along a sensor optical path. The sensor optical path is different from the source optical path. The bodies of the array of sensor modules are arranged in a planar tiling pattern with respect to a longitudinal axis of the planar target.

Abstract: A system includes a microchannel analysis region, a first fluid actuation device, a second fluid actuation device, a sensor, and a controller. The first fluid actuation device is at a first end of the microchannel analysis region. The second fluid actuation device is at a second end of the microchannel analysis region opposite to the first end. The sensor is within the microchannel analysis region between the first fluid actuation device and the second fluid actuation device. The sensor measures an impedance of a fluid within the microchannel analysis region. The controller activates the first fluid actuation device to generate a first pressure wave in the fluid and activates the second fluid actuation device to generate a second pressure wave in the fluid. The first pressure wave and the second pressure wave converge at the sensor.

Abstract: A droplet PCR system is described herein. The droplet PCR system comprises a chamber having a heating surface, a droplet dispenser to dispense PCR-reagent-containing droplets into the chamber, a heater disposed onto the heating surface of the chamber to heat a layer of fluid adjacent the heating surface, and a controller to control the heater to produce a pulsed heat flux.

Abstract: A microfluidic device includes a first channel, second channels, and a transition channel splitting the first channel into the second channels. The transition has a first end fluidically connected to the first channel and a second end fluidically connected to the second channels. The transition channel expands in width from a width of the first channel at the first end to no less than a sum of widths of the second channels at the second end so as to promote fluid flow from the first channel to the second channels.

Abstract: A microfluidic device includes a first channel having a first width and a second channel having a second width greater than the first width. The microfluidic device includes a transition channel having a first end fluidically connected to the first channel and a second end fluidically connected to the second channel. The transition channel expands in width from the first width to the second width so as to promote fluid flow from the first channel to the second channel.

Abstract: An example system includes an input channel having a first end and a second end to receive particles through the first end, a sensor to categorize particles in the input channel into one of at least two categories, and at least two output channels. Each output channel is coupled to the second end of the input channel to receive particles from the input channel, and each output channel is associated with at least one category of the at least two categories. Each output channel has a corresponding pump operable, based on the categorization of a detected particle in a category associated with a different output channel, to selectively slow, stop, or reverse a flow of particles into the output channel from the input channel.

Abstract: A fluid-ejection element of a fluid-ejection device includes a chamber layer having a pair of chambers fluidically disconnected from one another within the chamber layer. The fluid-ejection element includes a tophat layer over the chamber layer and fluidically connecting the chambers to define a fluid recirculation path between the chambers. The fluid-ejection element includes a nozzle common to both the chambers.

Abstract: A microfluidic system may comprise a dispense head with multiple dispensers, each dispensing a different cell type, such as single pairs of individual target cells and individual sensor cells. Interaction between the cells may be observed based on, for example, fluorescence. Individual target cells may then be selected, based on observations, for use or for further investigation. As an example, target cells may be B-cells, and enhanced selection of B-cells aids more direct antibody discovery.

Abstract: Fluid is continuously recirculated through a thermal fluid-ejection printhead. Prior to firing a thermal resistor of the printhead to thermally eject a drop of the fluid through a nozzle of the printhead, the fluid is recirculated on-demand through a chamber of the printhead between the nozzle and the thermal resistor. The thermal resistor is fired to thermally eject the drop of the fluid through the nozzle. The fluid has a concentration of solids greater than 12% by volume.

Abstract: A microfluidic device includes a chamber having sidewalls, a floor, a ceiling, and an inlet. The microfluidic device includes pillars extending from the floor to the ceiling of the chamber. Each pillar has an orientation relative to the inlet defined by a leading surface and a trailing corner opposite the leading corner. The trailing corner has an angle less than a threshold angle that is based on a fluidic contact angle. The orientations of the pillars relative to the inlet promote fluid flow from the inlet throughout the chamber without trapping gas at the sidewalls of the chamber.

Abstract: The present invention relates to a method for referencing a near-field measurement, e.g. in a scanning probe microscope.

Abstract: A microfluidic processing system can include a reagent delivery network including an inlet microfluidic channel fluidly coupled to an outlet microfluidic channel via a microfluidic cross-channel. The microfluidic cross-channel can include a constriction region and a reagent storage chamber. The microfluidic processing system can also include a resistor positioned along the inlet microfluidic channel at a location to redirect fluid through the constriction region and into a reagent storage chamber, and process microfluidics fluidly coupled downstream from the outlet microfluidic channel.