Methods for detecting target analytes utilizing an array of wells are advantageous for detection of low concentrations of target analytes. Use of an array of wells requires sealing of the wells. The methods provided herein utilize digital microfluidics to seal wells of an array with a fluid that is immiscible with the aqueous liquid present in the wells to prevent evaporation and contamination of the aqueous fluid during analysis of signals from the wells. The disclosed method include generating a biphasic droplet composed of the immiscible fluid and an aqueous fluid. The immiscible fluid present in the biphasic droplet is moved over the array of wells to seal the wells by electrically actuating the aqueous fluid present in the biphasic droplet which in turn pulls the immiscible fluid.

A digital microfluidic (DMF) system, DMF cartridge, and method including integrated refractive index (RI) sensing is disclosed. The digital microfluidic DMF system and DMF cartridge may include, for example, a RI sensor (or sensor surface) directly in the droplet operations gap of a DMF cartridge. The digital microfluidic DMF system may include, for example, the DMF cartridge, one or more illumination sources, one or more optical measurement devices, and a controller. Additionally, a method of using the DMF system and DMF cartridge that includes integrated RI sensing is provided.

A method for producing a liquid reaction mixture containing a radioisotope, in particular, a radioactive composition, minimizes device contamination with radioactive substances and increase speed and accuracy with which droplets are mixed. The method for producing a radioactive composition includes placing at least one first droplet L1 containing a radionuclide and at least one second droplet L2 containing a labeling substance on at least two respective dimples 5 among dimples 5 on a front surface 4b of an insulating layer 4 of a liquid manipulation device 1, and obtaining a liquid mixture M by using a change in electrostatic force caused by changing voltage applied to the electrodes 3 to thereby cause a relative movement between the at least one first droplet L1 and the at least one second droplet L2 so that the at least one first droplet L1 and the at least one second droplet L2 are mixed together at any one dimple among the dimples 5.

A digital microfluidic chip and a digital microfluidic system. The digital microfluidic chip comprises: an upper substrate and a lower substrate arranged opposite to each other; multiple driving circuits and multiple addressing circuits disposed between the lower substrate and the upper substrate; and a control circuit, electrically connected to the driving circuits and the addressing circuits. The control circuit is configured to apply, in a driving stage, a driving voltage to each driving circuit, such that a droplet is controlled to move inside a droplet accommodation space according to a set path, measure, in a detection stage, after a bias voltage is applied to each addressing circuit, a charge loss amount of each addressing circuit, and to determine the position of the droplet according to the charge loss amount. The charge loss amount of each addressing circuit is related to the intensity of received external light.

A liquid droplet manipulation system has a substrate with at least one electrode array and a central control unit for controlling selection of individual electrodes of the electrode array and for providing the electrodes with individual voltage pulses for manipulating liquid droplets by electrowetting. A working film is placed on top of the electrodes for manipulating samples in liquid droplets with the electrode array. At least one selected individual electrode of the electrode array is configured to be penetrated by light of an optical detection system for the optical inspection or analysis of samples in liquid droplets that are located on the working film. Also disclosed is working film that is to be placed on the electrode array and a cartridge that includes such a working film for manipulating samples in liquid droplets.

In one example an apparatus can include a controller communicatively coupled to a droplet dispenser to deposit fluid on a digital microfluidic (DMF) array including a plurality of droplet manipulation electrodes, the controller to: select a first droplet manipulation electrode from the plurality of droplet manipulation electrodes to on which to dispense a first volume of fluid via the droplet dispenser; position the droplet dispenser over the selected first droplet manipulation electrode; and deposit the first volume of fluid onto the selected first droplet manipulation electrode.

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.

A micro-total analysis system and a method thereof are provided. The micro-total analysis system includes: a microfluidic device, configured to accommodate a liquid to be detected; an optical unit, configured to form a first light irradiated to the microfluidic device; and a detection unit, configured to detect the liquid to be detected and output a detection signal to obtain detection information.

Droplet interfaces are formed between droplets in an electro-wetting device comprising an array of actuation electrodes. Actuation signals are applied to selected actuation electrodes to place the droplets into an energised state in which the shape of the droplets is modified compared to a shape of the droplets in a lower energy state and to bring the two droplets into proximity. The actuation signals are then changed to lower the energy of the droplets into the lower energy state so that the droplets relax into the gap and the two droplets contact each other thereby forming a droplet interface. The use of sensing electrodes in the device permit electrical current measurements across the droplet interface. The sensing electrodes can be used for either (i) applying a reference signal during droplet actuation or (ii) recording electrical current measurements.

Microfluidic devices and systems are provided. Methods for conducting immune assays with the devices and systems are also provided.