Abstract: A microfluidic system includes an electrowetting on dielectric (EWOD) device comprising an array of elements that are actuatable for manipulation of a liquid droplet within the EWOD device. The system has a pattern generator that generates an actuation pattern for actuating a portion of the elements in the array of elements, and a signal generator that generates voltage signals for actuating elements in the array of elements in accordance with the actuation pattern. The pattern generator generates an actuation pattern in which voltage signals applied to elements in at least part of a region at or adjacent to a contact line of the droplet are different from voltage signals applied to elements that are not in the part of the region at or adjacent to the contact line. The system further may include a sensor for sensing the droplet contact line constituting a boundary of the liquid droplet.

Abstract: A pixel circuit acts as a sensing element in a sensing device. The pixel circuit includes a sensing electrode, a first gate electrically connected to the sensing electrode, a second gate in electrical communication with the first gate, and a readout device that is electrically connected to the second gate. An input voltage applied to the sensing electrode is amplified between the first gate and the second gate, the amplification being measured as an output signal from the readout device to perform a sensing operation. For example, the output signal may be relatable to pH, analyte measurements, or other properties of sample liquids analyzed by the sensing device. A sensing device may include multiple pixels disposed on a substrate, each pixel including said pixel circuit. Driver circuits controlled by control electronics are configured to generate signals that selectively address the pixels and to read out voltages at the sensing electrodes.

Abstract: An active matrix electro-wetting on dielectric (AM-EWOD) device includes a plurality of array elements arranged in an array, each of the array elements including array element circuitry, an element electrode, and a reference electrode. The array element circuitry includes an actuation circuit configured to apply actuation voltages to the electrodes, and an impedance sensor circuit configured to sense impedance at the array element electrode to determine a droplet property at the array element. The impedance sensor circuit is operated by perturbing a potential applied to the reference electrode. The AM-EWOD device includes a common row addressing line. The impedance sensor circuit further is operated by supplying voltage signals over the common addressing line to effect both a reset operation and an operation for selecting a row in the array to be sensed. The circuitry isolates the array element from the actuation voltage during operating the impedance sensor circuit.

Abstract: An EWOD device for processing multiple droplets through multiple temperature zones. The device is configured to achieve a high spatial density of temperature zones with a wide temperature difference between hot and cold zones. A first set of temperature control elements is arranged above (or below) a fluid gap in an EWOD device and a second set of temperature control elements is arranged below (or above) the fluid gap. A temperature control element of one set is offset from temperature control elements of the other set in the plane of the fluid gap. The temperature control element of one set may be located at a different separation from the fluid gap to the temperature control element of the other set. The device has an optional temperature control element and/or arrangement which offsets the low temperature point from the inlet temperature. The two sets of temperature control elements are substantially interacting, in the sense that they cannot be considered to be thermally isolated from one another.

Abstract: A method of driving an active matrix electro-wetting on dielectric (AM-EWOD) device comprises (i) setting a reference electrode to a first reference voltage; (ii) writing a set of data to array element electrodes of array elements of the device; and (iii) either (a) maintaining the voltages written to the array element electrodes until a time t0 or (b) re-writing the set of data N?1 times (where N?2). The reference electrode is then set to a second reference voltage different from the first reference voltage, and features (i) to (iii) are repeated. When the data are first written, there is a delay between the time when the voltage on the reference electrode is transitioned and the time when a given array element is next written with data.

Abstract: An electrowetting on dielectric device includes: (a) a first substrate comprising electrodes at a surface of the first substrate configured to effect electrowetting mediated droplet operations; (b) a second substrate spaced from the surface of the first substrate to define an interior volume between the first substrate and the second substrate; (c) a liquid droplet disposed in the interior volume; and (d) a filler fluid disposed in the interior volume and surrounding the liquid droplet, wherein one or both of the liquid droplet and filler fluid contains a surfactant, the surfactant comprising a siloxane group represented by the structural formula: where n?1.

Abstract: A pixel circuit acts as a sensing element in a sensing device. The pixel circuit includes a sensing electrode, a first gate electrically connected to the sensing electrode, a second gate in electrical communication with the first gate, and a readout device that is electrically connected to the second gate. An input voltage applied to the sensing electrode is amplified between the first gate and the second gate, the amplification being measured as an output signal from the readout device to perform a sensing operation. For example, the output signal may be relatable to pH, analyte measurements, or other properties of sample liquids analyzed by the sensing device. A sensing device may include multiple pixels disposed on a substrate, each pixel including said pixel circuit. Driver circuits controlled by control electronics are configured to generate signals that selectively address the pixels and to read out voltages at the sensing electrodes.

Abstract: An EWOD (or AM-EWOD) device includes a reference electrode and a plurality of array elements, each array element including an array element electrode, and control electronics. In a first mode optimized for EWOD actuation, the control electronics is configured to control a supply of time varying voltages to the array element electrodes and the reference electrode, thereby generating an actuation voltage as a potential difference between voltages at the array element electrodes and the reference electrode. The reference electrode includes a first electrical connection and a second electrical connection. In a second mode, the control electronics further is configured to supply an electrical current flow between the first electrical connection and the second electrical connection to generate resistance heat for controlling temperature of the EWOD device. Control may include sensing a temperature of the EWOD device, and switching between operating in the first or second mode based on the sensed temperature.

Abstract: A method of driving an element of an active matrix electro-wetting on dielectric (AM-EWOD) device comprise applying a first alternating voltage to a reference electrode of the AM-EWOD device; and either (i) applying to the element electrode a second alternating voltage that has the same frequency as the first alternating voltage and that is out of phase with the first alternating voltage or (ii) holding the element electrode in a high impedance state. The effect of applying the second alternating voltage to the element electrode is to put the element in an actuated state in which the element is configured to actuate any liquid droplet present in the element, while the effect of holding the element electrode in the high impedance state is to put the element in a non-actuated state.

Abstract: An AM-EWOD device comprises: first and second substrates (72,36); first and second array element electrodes (38A, 38B) disposed on the first substrate (72) and defining first and second array elements in the AM-EWOD device; a reference electrode (28) disposed on the first substrate (72); a sensor; and a reference electrode drive circuit (50). The reference electrode drive circuit (50) is configured to drive the reference electrode with a first voltage waveform for actuating an array element or with a second voltage waveform different from the first voltage waveform when performing a sensing operation.

Abstract: An active matrix electrowetting on dielectric (AM-EWOD) device includes a plurality of array elements configured to manipulate one or more droplets of fluid on an array, each of the array elements including a corresponding array element circuit. Each array element circuit includes a top substrate electrode and a drive electrode between which the one or more droplets may be positioned, with an insulator layer being interposed between the one or more droplets and the drive electrode; and write circuitry configured to write data to the array element. At least some of the array element circuits include measure circuitry configured to detect a pinhole defect in the insulator layer.

Abstract: An active matrix electro-wetting on dielectric (AM-EWOD) device includes a plurality of array elements arranged in an array, each of the array elements including array element circuitry, an element electrode, and a reference electrode. The array element circuitry includes an actuation circuit configured to apply actuation voltages to the electrodes, and an impedance sensor circuit configured to sense impedance at the array element electrode to determine a droplet property at the array element. The impedance sensor circuit is operated by perturbing a potential applied to the reference electrode. The AM-EWOD device includes a common row addressing line. The impedance sensor circuit further is operated by supplying voltage signals over the common addressing line to effect both a reset operation and an operation for selecting a row in the array to be sensed. The circuitry isolates the array element from the actuation voltage during operating the impedance sensor circuit.

Abstract: An active matrix electro-wetting on dielectric (AM-EWOD) device includes a plurality of array elements arranged in an array, each array element including array element circuitry, an element electrode, and a reference electrode. The array element circuitry includes an actuation circuit configured to apply actuation voltages to the electrodes, and an impedance sensor circuit configured to sense impedance at the array element electrode to determine a droplet property. The actuation circuitry includes a memory capacitor for storing voltage data corresponding to either an actuated state or an unactuated state of the array element, and an input applied to the memory capacitor operates to effect an operation of the impedance sensor circuit. Such input may isolate the array element from the actuation voltage during operation of the impedance sensor circuit, and the memory capacitor may operate as part of the impedance sensor circuit as a reference capacitor for determining the droplet property.

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 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: In a method of performing dilution of a droplet in an EWOD device, a parent droplet is provided on an electrode array of the EWOD device, wherein the parent droplet has a first concentration of a species. A diluent droplet also is provided on the electrode array of the EWOD device. The method includes controlling actuation voltages applied to the electrode array of the EWOD device to join the parent droplet and the diluent droplet into a product droplet having a diluted second concentration of the species different from the first concentration in the parent droplet. The actuation voltages then are controlled to split the product droplet into one or more daughter droplets having the second concentration of the species. A dilution ratio may be calibrated based on the volumes of the droplets. Serial dilution steps may be performed to generate daughter droplets of different species concentrations at each step.

Abstract: In a method of performing dilution of a droplet in an EWOD device, a parent droplet is provided on an electrode array of the EWOD device, wherein the parent droplet has a first concentration of a species. A diluent droplet also is provided on the electrode array of the EWOD device. The method includes controlling actuation voltages applied to the electrode array of the EWOD device to join the parent droplet and the diluent droplet into a product droplet having a diluted second concentration of the species different from the first concentration in the parent droplet. The actuation voltages then are controlled to split the product droplet into one or more daughter droplets having the second concentration of the species. A dilution ratio may be calibrated based on the volumes of the droplets. Serial dilution steps may be performed to generate daughter droplets of different species concentrations at each step.

Abstract: An EWOD (or AM-EWOD) device includes a reference electrode and a plurality of array elements, each array element including an array element electrode, and control electronics. In a first mode optimized for EWOD actuation, the control electronics is configured to control a supply of time varying voltages to the array element electrodes and the reference electrode, thereby generating an actuation voltage as a potential difference between voltages at the array element electrodes and the reference electrode. The reference electrode includes a first electrical connection and a second electrical connection. In a second mode, the control electronics further is configured to supply an electrical current flow between the first electrical connection and the second electrical connection to generate resistance heat for controlling temperature of the EWOD device. Control may include sensing a temperature of the EWOD device, and switching between operating in the first or second mode based on the sensed temperature.

Abstract: An active matrix electrowetting on dielectric (AM-EWOD) device includes a plurality of array elements configured to manipulate one or more droplets of fluid on an array, each of the array elements including a corresponding array element circuit. Each array element circuit includes write circuitry configured to write data to the corresponding array element for controlling the manipulation of the droplets of fluid, and sensor circuitry configured to sense an impedance present at the corresponding array element. The sensor circuitry is configured to operate in one of a normal mode of sensitivity for detection of a droplet, or a high mode of sensitivity to detect an electric property of an array element hydrophobic surface. The sensor circuitry includes an active element, such as an active capacitor or active transistor, and a capacitance across the active element is different in the normal sensitivity mode as compared to the high sensitivity mode.

Abstract: An illumination system comprises at least two light sources (101,102,103) having different emission spectra to one another; a detection circuit (131,132,133) for sensing a light intensity using at least one of the light sources as a photosensor; and driving means (161,162,163) for driving the light source in dependence on the sensed spectral distribution of light. The emission spectrum of a light source with the smallest bandgap overlaps the emission spectrum of a light source with the second-smallest bandgap. The illumination system is possible to measure the intensity of light emitted by the light source with the smallest bandgap by putting the light source with the second-smallest bandgap in detection mode. The illumination system may also sense the spectral distribution of ambient light, to allow the output from the illumination system to be adjusted in dependence on the ambient light.