Abstract: A microfluidic bead-packing method includes activating a first micropump to transfer active microbeads through an inlet microchannel from a bead suspension reservoir to an adsorbing channel; packing the microbeads in the adsorbing channel; and activating a second micropump to reverse flow through at least a portion of the inlet microchannel and to transfer a sample fluid through the inlet microchannel from a sample reservoir to the adsorbing channel such that the sample fluid interacts with the packed microbeads.

Abstract: A microfluidic filtering system may include a first microfluidic channel, a first pump to move fluid along the first microfluidic channel in a first direction, a second microfluidic channel, a second pump to move fluid along the second microfluidic channel in a second direction opposite to the first direction and a filter channel extending between and interconnecting the first microfluidic channel and the second microfluidic channel.

Abstract: In one example in accordance with the present disclosure, an analyte capturing device is described. The analyte capturing device includes a first substrate having microfluidic channels disposed therein and a second substrate disposed on top of the first substrate. A chamber is disposed through the second substrate and captures beads therein, which beads adsorb analytes. The analyte capturing device includes at least one fluid ejection device disposed in the first substrate to draw an analyte-containing solution through the beads disposed within the chamber.

Abstract: A dual direction dispenser may include a fluid channel, a first ejection orifice extending in a first direction from the fluid channel, a first fluid actuator to displace fluid through the first ejection orifice, a second ejection orifice extending in a second direction, different than the first direction, from the fluid channel and a second fluid actuator to displace fluid through the second ejection orifice.

Abstract: According to an example, a three-dimensional (3D) printer may include a spreader to spread build material granules into a layer on a build area platform, a pressing die positioned above the layer of spread build material granules, in which the pressing die is to apply pressure onto the layer of build material granules to fragment the build material granules into primary particles to increase the density of the layer of build material granules, and a printhead to selectively deposit a fusing agent between the primary particles of the spread layer of build material granules.

Abstract: A three-dimensional object may be generated. Coalescing agent may be selectively delivered on a portion of a first layer of build material on a support member or previous layer. Energy may be applied to the first layer to cause the portion of the first layer to coalesce and solidify. A second layer of the build material may be provided on the first layer. While the second layer does not have coalescing agent delivered thereon, energy may be applied to the second layer such that energy may propagate through the second layer to the first layer to cause the portion of the first layer to coalesce and further solidify.

Abstract: A material development tool includes a first plate and a second plate. The first plate has an indentation of a predetermined depth. The second plate having an opening for receiving build material when placed on the first plate and is removable from the first plate. A recoater is used to move and spread the build material within the indentation of the first plate.

Abstract: A microfluidic valve may include a first portion of a liquid conduit to contain a fluid, a second portion of the liquid conduit to contain a liquid and a constriction between the first portion and the second portion and across which a capillary meniscus is to form between the fluid and liquid, the constriction comprising an edge along a ceiling of the constriction.

Abstract: A microfluidic immunoassay platform may include a substrate, a microfluidic channel in the substrate, a first set of functionalized structures along the channel, a second set of functionalized structures along the channel and an electrically driven fluid actuator contained on the substrate to move fluid containing at least one analyte along the channel through the first set of functionalized structures and through the second set of functionalized structures.

Abstract: An example method includes providing fluid to a chamber. The chamber feeds a first channel terminating at a first droplet ejector and a second channel terminating at a second droplet ejector. The method further includes sequencing ejection of droplets at the first droplet ejector and the second droplet ejector to induce negative pressure to provide a sequenced output flow of the fluid through the first channel to a first target microfluidic network and through the second channel to a second target microfluidic network, and controlling the first and second target microfluidic networks to perform an analytical process with the fluid.

Abstract: An object focuser may include a substrate, a sample fluid passage supported by the substrate, a first inertial pump supported by the substrate to pump a sample fluid entraining an object through the sample fluid passage, a first sheath fluid passage, a second inertial pump supported by the substrate to pump a first sheath fluid through the first sheath fluid passage, a second sheath fluid passage and a second inertial pump supported by the substrate to pump a second sheath fluid through the second sheath fluid passage. The first sheath fluid passage and the second sheath fluid passage are connected to the sample fluid passage at a convergence on opposite sides of the sample fluid passage.

Abstract: A microfluidic flow sensor may include a substrate having a microfluidic channel, a bubble generator to introduce a bubble into fluid that is directed through the microfluidic channel and a sensor element along the microfluidic channel and spaced from the bubble generator. The sensor element outputs a signal based upon a sensed passage of the bubble with respect to the sensor element. Portions of the microfluidic channel proximate the sensor element have a first size and wherein the bubble generated by the bubble generator is to have a second size greater than one half the first size.

Abstract: A microfluidic flow sensor may include a substrate having a microfluidic channel, an inert particle source to supply a fluid carrying an inert particle to the microfluidic channel and a sensor element along the microfluidic channel and spaced from the inert particle source. The sensor element outputs a signal based upon a sensed passage of the inert particle with respect to the sensor element. Portions of the microfluidic channel proximate the sensor element have a first size and wherein the inert particle provided by the inert particle source is to have a second size greater than one half the first size.

Abstract: One example provides a microfluidic mixing device that includes a main fluidic channel to provide main fluidic channel flow and a number of I-shaped secondary channels extending outwardly from a portion of the main fluidic channel. A number of inertial pumps are located within the I-shaped secondary channels to create serpentine flows in the direction of the main fluidic channel flow or create vorticity-inducing counterflow in the main fluidic channel.

Abstract: An example device includes a chamber to receive a fluid, a first channel in communication with the chamber, a second channel in communication with the chamber, a target microfluidic network at the second channel, a first droplet ejector positioned at the first channel to draw a first portion of fluid through the first channel, and a second droplet ejector positioned at the second channel downstream of the target microfluidic network. The second droplet ejector is to draw a second portion of fluid through the second channel and into the target microfluidic network.

Abstract: A microfluidic device may include a die package. The die package may include at least on fluidic die and an overmold material overmolding the fluidic die. The microfluidic device may also include a mesofluidic plate coupled to the die package. The mesofluidic plate includes at least one mesofluidic channel formed therein to fluidically couple the fluidic die.

Abstract: An example device includes a chamber including a fluid inlet, a fluid outlet, and a negative-pressure port. The negative-pressure port is positioned relative to the fluid inlet to draw a droplet of a fluid from the fluid inlet into the chamber when the fluid is applied to the fluid inlet and negative pressure is applied to the negative-pressure port. The fluid outlet is positioned relative to the fluid inlet to collect the droplet. The example device further includes a downstream microfluidic channel connected to the fluid outlet of the chamber. The downstream microfluidic channel communicates capillary action to the fluid outlet of the chamber. The capillary action resists flow of the fluid from the fluid outlet into the chamber induced by the negative pressure applied to the negative-pressure port.

Abstract: The present disclosure is drawn to inertial pumps. An inertial pump can include a microfluidic channel, a fluid actuator located in the microfluidic channel, and a check valve located in the microfluidic channel. The check valve can include a moveable valve element, a narrowed channel segment located upstream of the moveable valve element, and a blocking element formed in the microfluidic channel downstream of the moveable valve element. The narrowed channel segment can have a width less than a width of the moveable valve element so that the moveable valve element can block fluid flow through the check valve when the moveable valve element is positioned in the narrowed channel segment. The blocking element can be configured such that the blocking element constrains the moveable valve element within the check valve while also allowing fluid flow when the moveable valve element is positioned against the blocking element.

Abstract: An example system includes an input channel having a first end and a second end to receive particles through the first end, a separation chamber, at least two output channels, and an integrated pump to facilitate flow through the separation chamber. The separation chamber is in fluid communication with the second end of the input channel. The separation chamber has a passive separation structure, the passive separation structure including an array of columns spaced apart to facilitate separation of particles in a flow based on a size of the particles. Each output channel is in fluid communication with the separation chamber to receive separated particles. The integrated pump is positioned within at least one of the input channel or one of the at least two output channels.

Abstract: Examples include polymerase chain reaction (PCR) devices. Example PCR devices comprise a fluid input, ejection nozzles, and a set of microfluidic channels that fluidly connect the fluid input and the ejection nozzles. Each microfluidic channel comprises a reaction chamber, and examples further comprise at least one heating element, where the at least one heating element is positioned in the reaction chamber of each microfluidic channel. The at least one heating element is to heat fluid in the reaction chamber of each fluid channel. The device may eject fluid via the ejection nozzles.