A method of collecting resin beads includes first to fourth steps. The first step is a step of preparing a sample on a thin film provided on an upper surface of a substrate. The second step is a step of irradiating the thin film with a laser beam and a laser beam with the laser beam and the laser beam being distant from each other. The third step is a step of producing a microbubble at a position irradiated with the laser beam and producing a microbubble at a position irradiated with the laser beam, by heating the sample by irradiation with the laser beams. The fourth step is a step of collecting a plurality of resin beads in a region between the microbubble and the microbubble by producing convection of the sample in a direction perpendicular to a direction of alignment of the microbubble and the microbubble.

The disclosure provides a micro-fluidic chip, and belongs to the field of chip technology. The microfluidic chip provided in the present disclosure includes a plurality of microfluidic units, each microfluidic unit includes an operation region and a transition region located on at least one side of the operation region, the transition regions at adjacent side of two adjacent microfluidic units are disposed opposite to each other. Each microfluidic unit includes: a first substrate; a first electrode layer disposed on the first substrate, the first electrode layer including a plurality of first sub-electrodes located in the operation region and at least one second sub-electrode located in the transition region, and the at least one second sub-electrode configured to drive a droplet to move from one of the plurality of microfluidic units to an adjacent microfluidic unit.

Provided are microfluidic systems and methods for detecting, sorting, and dispensing of low abundance events such as single cells and particles, including a variety of eukaryotic and bacterial cells, for a variety of bioassay applications. The systems and methods described herein, when implemented in whole or in part, will make relevant microfluidic based tools available for a variety of applications in biotechnology including antibody discovery, immuno-therapeutic discovery, high-throughput single cell analysis, target-specific compound screening, and synthetic biology screening.

A switchable hydrophilic surface is created by attaching electrochemically switchable hydrophilicity polymers to the surface of a microelectrode array. Ferrocene polymers are one example of electrochemically switchable hydrophilicity polymers. Activation of electrodes in the microelectrode array changes the oxidation state of metal ions which switches the polymers between hydrophobic and hydrophilic conformations. Selective activation of electrodes can create patterns of wettability on the microelectrode array that may be varied in real time. The switchable hydrophilic surface may be used to control solid-phase synthesis of polymers. Growing polymers may be selectively extended at locations on the microelectrode array that are hydrophilic. The pattern of hydrophobic and hydrophilic regions can be changed during sequential rounds of synthesis to create a variety of different polymers at different locations on the surface of the microelectrode array.

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. The test metrics may include a transition rate and/or conformance to an actuation pattern.

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.

A method for holding an aqueous droplet in a selected location within a microfluidic device. The microfluidic device comprises: a top plate comprising a top substrate, a first layer of hydrophobic material applied to a surface of the top substrate, and a common top electrode between the first layer of hydrophobic material and the top substrate; a bottom plate comprising a pixel array, the pixel array comprising a plurality of pixel electrodes and a second layer of hydrophobic material applied over the plurality of pixel electrodes, and a microfluidic gap between the first and second layers of hydrophobic material. The method comprises: applying an intermittent driving pattern to pixels under the area of the droplet. The intermittent driving pattern comprises, in order: actuating a first subset of the pixels under the area of the droplet, and actuating a second subset of the pixels under the area of the droplet.

A method of generating droplets from a liquid sample is described and is characterised by the steps of a) locating the sample at a first electrowetting location and applying an electrowetting force to cause a region of the sample to become elongated in a direction in which the electrowetting force is applied; b) temporarily altering the electrowetting force on the sample and accumulating electrostatic surface charge on the sample to counter surface tension forces between the bulk of the sample and the elongated sample region; c) restoring the electrowetting force; d) further elongating the charged elongated sample region using the electrowetting force and e) severing a droplet from the charged elongated sample region. A corresponding droplet generator is also described.

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 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.