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.

Abstract: A reagent delivery network can include an inlet microfluidic channel, a microfluidic cross-channel branching off from the inlet microfluidic channel, a resistor positioned along the inlet microfluidic channel at a location to redirect fluid from the inlet microfluidic channel into the microfluidic cross-channel, and an outlet microfluidic channel having a side-wall opening connected to the microfluidic cross-channel. The outlet microfluidic channel can receive fluid from the microfluidic cross-channel. The microfluidic cross-channel can include a constriction region and a reagent storage chamber having reagent therein.

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: 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: A method comprising receiving, at a microfluidic channel, a biologic sample including a cell and providing a magnetic field within the microfluidic channel using a first magnet, wherein the magnetic field attracts a first plurality of magnetic particles disposed within the microfluidic channel. The method further includes activating a first resistor disposed within the microfluidic channel to agitate a volume of fluid within the microfluidic channel, and in response, moving the first plurality of magnetic particles through the microfluidic channel to lyse the cell and to release cellular material from the cell.

Abstract: An example microfluidic mixer can include an inlet microfluidic channel portion and a fluid splitting channel portion including an overpass microfluidic channel to receive fluid from a first side of the inlet microfluidic channel portion and an underpass microfluidic channel to receive fluid from a second side of the inlet microfluidic channel portion, where the underpass microfluidic channel extends under the overpass microfluidic channel such that the channels overlap at their respective downstream ends. A fluid recombining channel portion is downstream of the fluid splitting portion and includes an angled recombining surface having an acute angle with respect to a direction of fluid flow, where the angled recombining surface is between the downstream ends of the overpass and underpass microfluidic channels. An outlet microfluidic channel portion is fluidly connected downstream from the fluid recombining channel portion.

Abstract: In one example in accordance with the present disclosure, a fluid analysis system is described. The fluid analysis system includes an inlet channel to an analysis chamber. The analysis chamber is to receive a fluid sample to be analyzed. The fluid analysis system also includes a fluid branch having a fluidic junction along the inlet channel and a gas chamber to house a volume of trapped gas, the gas chamber being in fluid communication with the fluid branch. The fluid analysis system also includes a sealing fluid delivery system to fill the fluid branch with a sealing fluid and a heater adjacent the gas chamber to heat the gas chamber such that the trapped gas expands to push the sealing fluid into the inlet channel to seal the analysis chamber.

Abstract: A nucleic acid detection device includes a microfluidic opening and a sensor stack. The sensor stack includes an electrochemical electrode and a photodetector. The electrochemical electrode is formed of a conductive material that is transparent to a fluorescent emission, the electrochemical electrode including a first side and an opposite second side, wherein the first side is exposed to the microfluidic opening. The photodetector is positioned relative to the second side of the electrochemical electrode to optically receive the fluorescent emission when passed through the electrochemical electrode.

Abstract: A printing fluid pen includes a plurality of fluid ports, a pressure regulator in fluid communication with a first fluid port, and a valve in fluid communication with a second fluid port. The first fluid port is to deliver printing fluid to a fluid ejection device, and the second fluid port is to direct printing fluid out of the pen. In response to negative pressure, the valve is to open to enable fluids within the pen to exit via the second port.

Abstract: In one example in accordance with the present disclosure, a cellular analytic system is described. The cellular analytic system includes a series of analytic devices. Each analytic device includes 1) a separator to separate a cellular particle from a surrounding fluid, 2) an analyzer coupled to a first outlet of the separator to analyze the surrounding fluid, and 3) at least one lysing device coupled to at least a second outlet of the separator to rupture a membrane of the cellular particle. An outlet of the lysing device is fluidly coupled to a separator of a downstream analytic device.

Abstract: An example microfluidic device comprises a plurality of fluidic channels and a fluidic multiplexor. The fluidic multiplexor includes a plurality of fluidic micro-valves fluidically coupled to the plurality of fluidic channels, and a plurality of control lines that cross the plurality of fluidic channels proximal to the plurality of fluidic micro-valves.

Abstract: An example microfluidic structure can include a first microfluidic channel segment in a first elevation plane, a second microfluidic channel segment in a second elevation plane, and a transverse microfluidic channel segment connecting the first microfluidic channel segment to the second microfluidic channel segment. An interior pillar can be positioned at the transverse microfluidic channel segment. The interior pillar can have a tapered downstream edge. The tapered downstream edge can be angled in the first or second elevation plane at an acute angle. A fluid cross-sectional area can increase in the fluid flow direction along the tapered downstream edge.

Abstract: An example microfluidic structure can include a first microfluidic channel segment in a first elevation plane, a second microfluidic channel segment in a second elevation plane, and a transverse microfluidic channel segment connecting the first microfluidic channel segment to the second microfluidic channel segment. An angled exterior wall segment can be at the transverse microfluidic channel segment. The angled exterior wall segment can be angled in the first or second elevation plane at an acute angle with respect to a direction of fluid flow through the first or second microfluidic channel segment. A fluid cross-sectional area can increase in the fluid flow direction along the angled exterior wall segment.

Abstract: In one example in accordance with the present disclosure, a fluid manipulation system is described. The fluid manipulation system includes a microfluidic channel through which fluid is to flow. The fluid includes biomolecules to be separated. The fluid manipulation system also includes at least one array of biomolecule-capturing pillars disposed within the microfluidic channel to capture biomolecules from the fluid. Barriers rise from a surface of the microfluidic channel. The barriers span a width of the microfluidic channel orthogonal to a flow of the fluid to induce vortices in the fluid flow.

Abstract: An example method, consistent with the present disclosure, includes receiving in a microfluidic channel, a fluid sample and a reagent, where the reagent includes a reporter nucleic acid labeled with a detectable ligand. The method further includes identifying a target nucleic acid in the fluid sample using a guide ribonucleic acid (gRNA) and a programmable nuclease immobilized in a side channel fluidically coupled to the microfluidic channel. Responsive to identifying the target nucleic acid in the fluid sample, the method includes causing cleavage of the detectable ligand, and detecting the detectable ligand from the cleaved reporter nucleic acid in the side channel.