Abstract: An electro-wetting on dielectric (EWOD) device, includes first and second substrates defining a fluid chamber therebetween, a plurality of electro-wetting electrodes on the first substrate, and at least one first electrode and at least two second electrodes on the second substrate. The device further includes a current sensor or sensing a difference between (1) a first current flowing between the first electrode and one of the second electrodes via a first fluid package in the fluid chamber of the EWOD device and (2) a second current flowing between the first electrode and another of the second electrodes via a second fluid package in the fluid chamber of the EWOD device.

Abstract: An electro-wetting on dielectric (EWOD) device, comprises first and second substrates defining a fluid chamber therebetween, a plurality of electro-wetting electrodes on the first substrate, and at least one first electrode and at least two second electrodes on the second substrate. The device further includes a current sensor for sensing a difference between (1) a first current flowing between the first electrode and one of the second electrodes via a first fluid package in the fluid chamber of the EWOD device and (2) a second current flowing between the first electrode and another of the second electrodes via a second fluid package in the fluid chamber of the EWOD device.

Abstract: A microfluidic AM-EWOD device and a method of filling such a device are provided. The device comprises a chamber having one or more inlet ports. The device is configured, when the chamber contains a metered volume of a filler fluid that partially fills the chamber, preferentially maintain the metered volume of the filler fluid in a part of the chamber. The device is configured to allow displacement of some of the filler fluid from the part of the chamber when a volume of an assay fluid introduced into one of the one or more inlet ports enters the part of the chamber, thereby causing a volume of a venting fluid to vent from the chamber.

Abstract: A microfluidic AM-EWOD device and a method of filling such a device are provided. The device comprises a chamber having one or more inlet ports. The device is configured, when the chamber contains a metered volume of a filler fluid that partially fills the chamber, preferentially maintain the metered volume of the filler fluid in a part of the chamber. The device is configured to allow displacement of some of the filler fluid from the part of the chamber when a volume of an assay fluid introduced into one of the one or more inlet ports enters the part of the chamber, thereby causing a volume of a venting fluid to vent from the chamber.

Abstract: A microfluidic device performs a method of partitioning droplets from a fluid reservoir containing particles that provides a non-Poissonian distribution of dispensed droplets containing a desired number of particles. Using an electrowetting on dielectric (EWOD) device, droplets are dispensed having a Poissonian distribution of dispensed droplets containing a desired number of particles, and the droplets are interrogated to determine whether each dispensed droplet has a desired number of particles. Droplets that contain the desired number of particles are moved by EWOD operation to a reaction area on the EWOD device, and droplets that do not contain the desired number of particles are rejected and moved by EWOD operation to a holding area on the EWOD device that is different and spaced apart from the reaction area. The result is that droplets in the reaction area have a non-Poissonian distribution of droplets containing the desired number of particles.

Abstract: A heating system for an EWOD device using a single, spatially-structured temperature control element, used to create a zone with a specific temperature profile. The heating system uses multiple contact regions between the temperature control element and the device. One or more contact regions are separated from the temperature control element by one or more thermally resistive layers that restrict heat flow from the temperature control element to the device, and further restrict lateral flow of heat between adjacent contact regions. The heating system can use materials with different thermal resistance to alter the heat flow to different regions. The spatial location of the contact regions is also used to determine the temperature profile within the device. The device has an optional temperature control element which offsets the low temperature point from the inlet temperature. This invention includes methods to process multiple droplets within the multiple temperature zones.

Abstract: A method of operating an electrowetting on dielectric (EWOD) device performs electrowetting operations on fluids dispensed into the EWOD device, which provides enhanced operation for using multiple non-polar filler fluids.

Abstract: A microfluidic device comprises upper and lower spaced apart substrates defining a fluid chamber therebetween; an aperture for introducing fluid into the fluid chamber; and a fluid input structure disposed over the upper substrate and having a fluid well for receiving fluid from a fluid applicator inserted into the fluid well. The fluid well communicates with a fluid exit provided in a base of the fluid input structure, the fluid exit being adjacent the aperture. The fluid well comprises first, second and third portions, with the first portion of the well forming a reservoir for a filler fluid; and the second portion of the well being configured to sealingly engage against an outer surface of a fluid applicator inserted into the fluid well. The third portion of the well communicates with the fluid exit and has a diameter at the interface between the third portion and the second portion that is greater than the diameter of the second portion at the interface between the third portion and the second portion.

Abstract: A method of determining the result of an assay in a microfluidic device includes the steps of: dispensing a sample droplet onto a first portion of an electrode array of the microfluidic device; dispensing a reagent droplet onto a second portion of the electrode array of the microfluidic device; controlling actuation voltages applied to the electrode array to mix the sample droplet and the reagent droplet into a product droplet; sensing a dynamic property of the product droplet; and determining an assay of the sample droplet based on the sensed dynamic property. The dynamic property is a physical property of the product droplet that influences a transport property of the product droplet on the electrode array. Example dynamic properties of the product droplet include the moveable state, split-able state, and viscosity based on droplet properties. The method may be used to perform an amoebocyte lysate (LAL) assay.

Abstract: A microfluidic system and related methods of operating an electrowetting on dielectric (EWOD) device operate to concentrate particles within a liquid droplet dispensed onto an element array of the EWOD device. The method includes the steps of providing a non-polar liquid onto the element array of the EWOD device; providing a polar liquid droplet onto the element array of the EWOD device within the non-polar liquid, wherein the polar liquid droplet includes particles; and applying an actuation cycle comprising a plurality of actuation patterns, wherein at least one of the actuation patterns includes actuating one or more array element electrodes within a perimeter of the polar liquid droplet, and the particles migrate within the polar liquid droplet to become concentrated within a portion of the liquid droplet at one or more array element electrodes corresponding to one of the plurality of actuation patterns.

Abstract: A microfluidic device comprises upper and lower spaced apart substrates defining a fluid chamber therebetween; an aperture for introducing fluid into the fluid chamber; a plurality of independently addressable array elements, each array element defining a respective region of the fluid chamber; and control means for addressing the array elements. The control means are configured to: determine that a working fluid has been introduced into a first region of the fluid chamber; and provide an output to a user to indicate that the working fluid is present in the first region. Once the working fluid is in the first region, the fluid applicator used to dispense the fluid can be removed without any risk of accidentally withdrawing dispensed working fluid from the microfluidic device.

Abstract: A method of operating an electrowetting on dielectric (EWOD) device performs electrowetting operations on fluids dispensed into the EWOD device, which provides enhanced operation for using multiple non-polar filler fluids.

Abstract: Provided is a microfluidic device that, as compared with a conventional microfluidic device, (i) is smoother in surface of a water-repellent layer provided above a segment electrode and (ii) makes it easier for microfluid provided in the surface of the water-repellent layer to slide. A microfluidic device (1) includes: an array substrate (10) including a plurality of electrodes (14); and a counter substrate (40) including at least one electrode (42), the array substrate (10) and the counter substrate (40) having therebetween an internal space (50) in which to cause an electroconductive droplet (51) to move across the plurality of electrodes (14), and the plurality of electrodes (14) being provided on a first flattening resin layer (13) and each being a light-blocking metal electrode.

Abstract: A microfluidic control system for controlling an EWOD device has an enhanced thermal control system for generating a temperature profile within an EWOD device that is inserted into the microfluidic control system. The microfluidic control system includes a housing that defines an aperture for receiving an EWOD device; an active heating component located within the housing at a base of the aperture; and a lid attached to the housing that is moveable between a closed position and an open position, the lid including a thermal control component. When the lid is in the closed position, the thermal control component is positioned at the aperture and aligned oppositely from the active heating component. The active heating component may include a plurality of independently controllable individual heating elements, and the thermal control component may include a respective plurality of individual thermal control elements.

Abstract: A method of operating an electrowetting on dielectric (EWOD) device performs microfluidic diffusion separation.

Abstract: An EWOD device and a related method of performing a digital biological assay are described that employs two volume measurements for enhanced assay determination. The method includes partitioning a sample reservoir and measuring the volume of each partition; initiating a biological assay wherein the biological assay includes measuring a partition property and a volume of each partition in real time as part of determining a concentration of the product substance in each partition based on the measured partition property and volume; and categorizing the partitions by a number of biological entities contained in each partition from which the number of biological entities may be calculated, which in turn may be used to calculate the total number of biological entities or concentration in the sample reservoir. The method further may include an enhanced partitioning process that minimizes variation in the volume of the partitions.

Abstract: A control method and related apparatus are disclosed for controlling actuation voltages applied to array elements of an element array on an electrowetting on dielectric (EWOD) device, wherein test metrics are determined and employed for optimizing subsequent droplet manipulation operations. The control method includes the steps of: receiving a liquid droplet onto the element array; applying an electrowetting actuation pattern of actuation voltages to actuate the droplet to modify a footprint of the droplet from a first state having an initial footprint to a second state having a modified footprint; sensing the modified footprint with a sensor; determining a test metric from sensing the modified footprint indicative of one or more droplet properties based on a droplet response of the liquid droplet to the electrowetting actuation pattern; and controlling actuation voltages applied to the array elements based on the test metric.

Abstract: A method of digital quantification of a species in an EWOD device includes inputting a sample volume and a diluent volume into the EWOD device; performing an electrowetting operation to generate a first sample droplet from the sample volume; performing an amplification process on the first sample droplet and measuring a turn-on value for the sample droplet; comparing the measured turn-on value to a target turn-on value for digital quantification; calculating a dilution factor based on the comparison of the measured and target turn-on values; performing an electrowetting operation to extract a second sample droplet from the sample volume; performing an electrowetting operation to dilute the second sample droplet with the diluent volume by the dilution factor to form a diluted second sample droplet; and performing a digital quantification on the diluted second sample droplet to quantify an initial concentration of the species in the sample volume.

Abstract: 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.

Abstract: A method of determining the result of an assay in a microfluidic device includes the steps of: dispensing a sample droplet onto a first portion of an electrode array of the microfluidic device; dispensing a reagent droplet onto a second portion of the electrode array of the microfluidic device; controlling actuation voltages applied to the electrode array to mix the sample droplet and the reagent droplet into a product droplet; sensing a dynamic property of the product droplet; and determining an assay of the sample droplet based on the sensed dynamic property. The dynamic property is a physical property of the product droplet that influences a transport property of the product droplet on the electrode array. Example dynamic properties of the product droplet include the moveable state, split-able state, and viscosity based on droplet properties. The method may be used to perform an amoebocyte lysate (LAL) assay.