A method of detecting passage of a particle into a target location includes receiving a sample on a die including a microfluidic chamber, the microfluidic chamber including a microfluidic path coupling a reservoir to a foyer, and moving the sample from the reservoir to the foyer by firing a nozzle fluidically coupled to the foyer. The method further includes detecting passage of a particle of the sample from the reservoir to the foyer via a first sensor disposed within the microfluidic path, and detecting passage of the particle into the target location via a second sensor disposed between the first sensor and the nozzle. The method includes recording in a dispense map, an indication of whether the target location includes a single particle or multiple particles based on signals measured by the first sensor and the second sensor.

Systems and methods for positive dispense verification. In one aspect, a system has a plurality of light emitters. The light from the emitters is directed toward a plurality of light detectors across a proximately horizontal plane. The liquid dispense device is positioned above the horizontal plane of light emission from the plurality of light emitters to the plurality of light detectors such that the dispensed liquid will travel through the horizontal plane defined by the emitted light and onto the container being inoculated. Each of the plurality of detectors is coupled to an amplifier. The amplifier generates a signal in response to an interrupt in the transmission of light from the light emitters to the light detectors when the light path is disrupted by the dispense of liquid confirming the liquid was dispensed onto the container.

A method of partitioning droplets from a fluid reservoir containing particles provides a non-Poissonian distribution of dispensed droplets containing a desired number of particles. The method constitutes a method of operating an electrowetting on dielectric (EWOD) device including the steps of: inputting a fluid reservoir containing particles into the EWOD device; performing an electrowetting operation to dispense a plurality of dispensed droplets from the fluid reservoir; interrogating each droplet with a detector and determining whether each dispensed droplet has a desired number of particles; selecting dispensed droplets that contain the desired number of particles and performing an electrowetting operation to move the selected dispensed droplets to a reaction area on the EWOD device; and rejecting dispensed droplets that do not contain the desired number of particles and performing an electrowetting operation to move the rejected dispensed droplets to a holding area on the EWOD device that is different and spaced apart from the reaction area. The selected droplets may be combined, including with or without a portion of the rejected droplets and/or additional reagent, into a larger reaction droplet that may be used in subsequent reaction protocols.

A droplet dispensing apparatus includes a crystal sensor, a resonance frequency measuring unit, and a controller. The controller is configured to obtain the resonance frequency of the crystal sensor before droplets are discharged from a liquid dropping device, control the liquid dropping device to discharge droplets on to the crystal sensor, and obtain the resonance frequency of the crystal sensor after droplets are discharged from the liquid dropping device. The controller estimates a volatilization amount for the droplets on the crystal sensor based on a temporal change trend in the resonance frequency of the crystal sensor and calculates the total weight of the droplets discharged from the liquid dropping device based on the difference in resonance frequency of the crystal sensor before and after the droplets are discharged and the estimated volatilization amount.

Means and methods for dispensing small amounts of liquid from multi-channel microdispensing devices, suitable for use in automatic processing in biological assays and for the cultivation of cells and tissues, by means of optical control of the dosed liquid by specific light barrier units.

A micro-fluidic device 100 for performing digital PCR is presented. The device comprises: a semiconductor substrate; a first micro-fluidic channel 104, comprising an inlet 102 and an outlet 103, embedded in the semiconductor substrate; a heating element 101 thermally coupled to the first micro-fluidic channel 104; a droplet generator 107 connected to the inlet 102 of the first micro-fluidic channel 104 for generating droplets and pumping generated droplets at a flow rate into the first micro-fluidic channel 104; characterized in that: the heating element 101 is a single heating element connected to a temperature control unit 111 configured to cycle the temperature of the complete first micro-fluidic channel 104 through at least two temperature values; and wherein the flow rate of the droplet generator 107 is adaptable. Further, a method to perform digital PCR is presented using the micro-fluidic device 100.

The invention provides methods for assessing one or more predetermined characteristics or properties of a microfluidic droplet within a microfluidic channel, and regulating one or more fluid flow rates within that channel to selectively alter the predetermined microdroplet characteristic or property using a feedback control.

A system and method for dispense characterization is disclosed. According to particular embodiments of the dispense characterization system and method, volumes of dispensed liquids can be determined. In more particular embodiments, additional characteristics and combinations of characteristics of a liquid dispensing event can be determined. Examples of additional characteristics that can be determined include the shape of the dispensing event, the velocity of the dispensing event, and the trajectory of the dispensing event. The dispense characterization system and method can be employed in automated biological sample analysis systems, and are particularly suited for monitoring liquid reagent dispensing events that deliver liquid reagents to a surface of a microscope slide holding a biological sample.

A system and method for dispense characterization is disclosed. According to particular embodiments of the dispense characterization system and method, volumes of dispensed liquids can be determined. In more particular embodiments, additional characteristics and combinations of characteristics of a liquid dispensing event can be determined. Examples of additional characteristics that can be determined include the shape of the dispensing event, the velocity of the dispensing event, and the trajectory of the dispensing event. The dispense characterization system and method can be employed in automated biological sample analysis systems, and are particularly suited for monitoring liquid reagent dispensing events that deliver liquid reagents to a surface of a microscope slide holding a biological sample.

A device for determining a position and/or an extension of a drop in a position determination space, where the device has a camera having an objective and a beam splitter in the recording area of the camera, and the device is designed in such a way that light coming from the position determination space can enter the objective of the camera along a first light path as well as along a second light path, where light along the first light path can be reflected at a first reflector element in the direction of the beam splitter and can be transmitted through the beam splitter towards the objective, and where light along the second light path can be reflected at a second reflector element in the direction of the beam splitter and can be reflected at the beam splitter towards the objective.