Device and method for making discrete volumes of a first fluid in contact with a second fluid, which are immiscible with each other

Abstract

A method for forming discrete volumes of aqueous fluid may comprise flowing aqueous fluid into a first conduit from a supply of aqueous fluid and flowing into the first conduit a spacing liquid supplied from a second conduit, the spacing liquid being immiscible with the aqueous fluid. The flowing of the aqueous fluid and the spacing liquid into the first conduit forms discrete volumes of the aqueous fluid, with consecutive discrete volumes of the aqueous fluid separated by the spacing liquid. The method may further comprise transferring the discrete volumes of the aqueous fluid and spacing liquid from the first conduit to a third conduit for processing.

1 - 15 . (canceled) 
     
     
         16 . A method comprising:
 directing a first flow of a plurality of discrete volumes of a first liquid comprising a biological sample through a first conduit of a fluidic network;   directing a second flow of a second liquid through a second conduit of the fluidic network, wherein the first liquid and second liquid are immiscible with one another;   merging the first and second flows at a junction where the first and second conduits intersect;   adjusting one or both of said first and second flows to control spacing between consecutive discrete volumes of the plurality of discrete volumes; and   detecting an optical signal from said discrete volumes, said optical signal indicative of a presence or absence of a biological analyte in the discrete volumes.   
     
     
         17 . The method of  claim 16 , wherein detecting the optical signal comprises using a fluorescence detector to detect for fluorescence from said discrete volumes. 
     
     
         18 . The method of  claim 17 , further comprising flowing the discrete volumes past the fluorescence detector and detecting for fluorescence individually in each of the discrete volumes as the discrete volumes flow past the fluorescence detector. 
     
     
         19 . The method of  claim 16 , wherein the first liquid comprises nucleic acid and the second liquid comprises oil. 
     
     
         20 . The method of  claim 16 , wherein detecting the optical signal indicative of a presence of a biological analyte comprises detecting an optical signal produced from amplicons of amplified nucleic acid. 
     
     
         21 . The method of  claim 16 , further comprising forming the plurality of discrete volumes of the first liquid. 
     
     
         22 . The method of  claim 21 , wherein forming the plurality of discrete volumes of the first liquid comprises introducing alternating volumes of the first liquid and a spacing fluid immiscible with the first liquid into a third conduit upstream of the first and second conduits. 
     
     
         23 . The method of  claim 16 , further comprising diluting the biological sample such that about one target nucleic acid fragment from the biological sample is in each of the plurality of discrete volumes. 
     
     
         24 . The method of  claim 16 , further comprising thermal cycling the discrete volumes of the first liquid. 
     
     
         25 . The method of  claim 24 , further comprising subjecting the discrete volumes of the first liquid to a nucleic acid amplification reaction. 
     
     
         26 . The method of  claim 16 , further comprising pipetting the plurality of discrete volumes and a spacing liquid immiscible with the first liquid from a well plate prior to delivering the plurality of discrete volumes to the first conduit. 
     
     
         27 . A system comprising:
 a fluidic network comprising a first conduit in fluidic communication with one or more additional conduits respectively coupled with the first conduit through one or more junctions;   a flow control system operably coupled to the fluidic network and configured to adjust a flow of one or both of (i) a plurality of discrete volumes of a first liquid in the first conduit of the fluidic network and (ii) a second liquid immiscible with the first liquid in at least one of the one or more additional conduits in fluidic communication with the first conduit, such that a spacing between individual discrete volumes of the plurality of discrete volumes of the first liquid is adjustable; and   an optical signal detector positioned relative to said fluidic network and configured to detect an optical signal from said individual discrete volumes, said optical signal indicative of a presence or absence of a biological analyte in said individual discrete volumes.   
     
     
         28 . The system of  claim 27 , wherein the optical signal detector comprises a fluorescence detector. 
     
     
         29 . The system of  claim 28 , wherein the fluorescence detector is configured to detect fluorescence from a fluorescent marker of a nucleic acid amplification and detection assay. 
     
     
         30 . The system of  claim 28 , wherein the fluorescence detector is configured to detect fluorescence from said discrete volumes as the discrete volumes flow individually past an optical path of the fluorescence detector. 
     
     
         31 . The system of  claim 27 , further comprising a pressure differential source operably coupled to the fluidic network and the flow control system. 
     
     
         32 . The system of  claim 27 , further comprising a thermal cycling device configured to thermally cycle the plurality of discrete volumes in the fluidic network. 
     
     
         33 . The system of  claim 27 , further comprising a pipette fluidically coupled to the fluidic network upstream of the first conduit and configured to pipette the plurality of discrete volumes of the first liquid and a spacing fluid immiscible with the first liquid into the pipette. 
     
     
         34 . The system of  claim 33 , further comprising:
 a platform configured to support a well plate relative to the pipette; and   a motion system configured to move the platform and well plate relative to each other to enable the pipette to pipette from differing wells of the well plate.   
     
     
         35 . The system of  claim 27 , wherein the optical signal detector is configured to detect an optical signal produced from amplicons of amplified nucleic acid in individual ones of the plurality of discrete volumes.