Abstract: The present invention generally relates to systems and methods for mixing and dispensing a sample droplet from a microfluidic system, such as a liquid bridge system. In certain embodiments, the invention provides systems for mixing and dispensing sample droplets, including a sample acquisition stage, a device for mixing sample droplets to form sample droplets wrapped in an immiscible carrier fluid, a dispensing port, and at least one channel connecting the stage, the droplet mixing device, and the port, in which the system is configured to establish a siphoning effect for dispensing the droplets.

Abstract: A microfluidic connector (1) comprises an enclosure (6, 7), a fluidic inlet port (2) and a fluidic outlet port (3), in the enclosure, in which the inlet and outlet ports (2, 3) are movable with respect to each other, for example, mutual spacing between the inlet and outlet ports (2, 3) is variable. A port (2) is in a fixed part (6) of the enclosure, and another port (3) is in a part (7) of the enclosure which slides with respect to the fixed part. There may be multiple inlet ports (22, 23) and/or multiple outlet ports (24, 25). Also, there may be an auxiliary port (45) for introduction of fluid into the enclosure (47, 48) or removal of fluid from the enclosure.

Abstract: The invention provides methods of conducting a nucleic acid reaction, including methods for performing digital PCR using a “droplet-in-oil” technology. In the methods, the starting sampled is segmented at least partially into a set of sample droplets each containing on average about one or fewer copies of a target nucleic acid. The droplets are passed in a continuous flow of immiscible carrier fluid through a channel that passes through a thermal cycler, whereby the target is amplified. In one implementation, the droplets are about 350 nl each and the number of positively amplified droplets is counted at the near-saturation point.

Abstract: A microfluidic analysis system (1) performs polymerase chain reaction (PCR) analysis on a bio sample. In a centrifuge (6) the sample is separated into DNA and RNA constituents. The vortex is created by opposing flow of a silicon oil primary carrier fluid effecting circulation by viscous drag. The bio sample exits the centrifuge enveloped in the primary carrier fluid. This is pumped by a flow controller (7) to a thermal stage (9). The thermal stage (9) has a number of microfluidic devices (70) each having thermal zones (71, 72, 73) in which the bio sample is heated or cooled by heat conduction to/from a thermal carrier fluid and the primary carrier fluid. Thus, the carrier fluids envelope the sample, control its flowrate, and control its temperature without need for moving parts at the micro scale.

Abstract: An apparatus (1) is for DNA amplification with quantitative measurements. A biological sample is held in a cell (2) for the amplification, the cell (2) defining a single space within which the sample rotates. On one side a copper heater (3) is located to supply heat to the cell (2), and on the other side there is a cooling copper block (4) withdrawing heat from the cell. The locations of the heater (3) and the cooling block (4) generate a natural convection loop internally within the cell (2) without need for active cooling—the block (4) passively cooling by withdrawing heat from the direction of the heater (3). A detector (9, 27) captures readings in real time and a processor (10) generates an S-curve for change of sample emission with time. The S-curve (FIGS. 4 and 5) also includes a thermal cycle number corresponding to the time parameter, so that the S-curve is given in the traditional qPCR intensity vs. cycle number.

Abstract: Measurement of gene expression relative to an endogenous control gene is prone to excessive variability between samples and even replicates. The disclosure provides methods for normalizing expression levels of a gene by scaling gene expression levels to that of the most highly expressed gene in the set of genes whose expression levels are measured, rather than a house-keeping gene.

Abstract: A multi-port liquid bridge (1) adds aqueous phase droplets (10) in an enveloping oil phase carrier liquid (11) to a draft channel (4, 6). A chamber (3) links four ports, and it is permanently full of oil (11) when in use. Oil phase is fed in a draft flow from an inlet port (4) and exits through a draft exit port (6) and a compensating flow port (7). The oil carrier and the sample droplets (3) (“aqueous phase”) flow through the inlet port (5) with an equivalent fluid flow subtracted through the compensating port (7). The ports of the bridge (1) are formed by the ends of capillaries held in position in plastics housings. The phases are density matched to create an environment where gravitational forces are negligible. This results in droplets (10) adopting spherical forms when suspended from capillary tube tips. Furthermore, the equality of mass flow is equal to the equality of volume flow.

Abstract: A microfluidic analysis system (1) performs polymerase chain reaction (PCR) analysis on a bio sample. In a centrifuge (6) the sample is separated into DNA and RNA constituents. The vortex is created by opposing flow of a silicon oil primary carrier fluid effecting circulation by viscous drag. The bio sample exits the centrifuge enveloped in the primary carrier fluid. This is pumped by a flow controller (7) to a thermal stage (9). The thermal stage (9) has a number of microfluidic devices (70) each having thermal zones (71, 72, 73) in which the bio sample is heated or cooled by heat conduction to/from a thermal carrier fluid and the primary carrier fluid. Thus, the carrier fluids envelope the sample, control its flowrate, and control its temperature without need for moving parts at the micro scale.

Abstract: A thermal cycling device (3) device a number of fixed thermal zones (11, 12, 13) and a fixed conduit (10) passing through the thermal zones. A controller maintains each thermal zone including its section of conduit (10) at a constant temperature. A series of droplets flows through the conduit (10) so that each droplet is thermally cycled, and a detection system detects fluorescence from droplets at all of the thermal cycles. The conduit is in a single plane, and so a number of thermal cycling devices may be arranged together to achieve parallelism. The flow conduit comprises a channel (17) and a capillary tube (10) inserted into the channel. The detection system may perform scans along a direction to detect radiation from a plurality of cycles in a pass.

Abstract: A bridge (30) comprises a first inlet port (31) at the end of a capillary, a narrower second inlet port (32) which is an end of a capillary, an outlet port (33) which is an end of a capillary, and a chamber (34) for silicone oil. The oil is density-matched with the reactor droplets such that a neutrally buoyant environment is created within the chamber (34). The oil within the chamber is continuously replenished by the oil separating the reactor droplets. This causes the droplets to assume a stable capillary-suspended spherical form upon entering the chamber (34). The spherical shape grows until large enough to span the gap between the ports, forming an axisymmetric liquid bridge. The introduction of a second droplet from the second inlet port (32) causes the formation of an unstable funicular bridge that quickly ruptures from the, finer, second inlet port (32), and the droplets combine at the liquid bridge (30).