Microfluidic devices

Abstract

The present invention provides novel microfluidic substrates and methods that are useful for performing biological, chemical and diagnostic assays. The substrates can include a plurality of electrically addressable, channel bearing fluidic modules integrally arranged such that a continuous channel is provided for flow of immiscible fluids.

1 - 74 . (canceled) 
     
     
         75 . A method for positioning a droplet within a channel, the method comprising:
 providing a channel that comprises one or more geometric features in the channel, the one or more features arranged to direct a droplet to a position in the channel;   flowing a droplet through the channel; and   causing the droplet to interact with the one or more geometric features in the channel, thereby positioning the droplet as it flows in the channel.   
     
     
         76 . The method according to  claim 75 , wherein the features are a plurality of raised pillars. 
     
     
         77 . The method according to  claim 75 , wherein the feature is a barrier that obstructs a portion of the channel. 
     
     
         78 . The method according to  claim 75 , wherein the one or more features are one or more indentations. 
     
     
         79 . The method according to  claim 75 , wherein the one or more geometric features are arranged to direct the droplet toward a side of the channel. 
     
     
         80 . The method according to  claim 79 , wherein at least one electrode is positioned in proximity to the side of the channel. 
     
     
         81 . The method according to  claim 80 , wherein the electrode emits an electric field through which the droplet passes. 
     
     
         82 . The method according to  claim 75 , wherein the droplet is surrounded by an immiscible fluid. 
     
     
         83 . The method according to  claim 82 , wherein the immiscible fluid is an oil. 
     
     
         84 . The method according to  claim 83 , wherein the oil is a fluorinated oil. 
     
     
         85 . The method according to  claim 83 , wherein the oil comprises a surfactant. 
     
     
         86 . The method according to  claim 85 , wherein the surfactant is a fluorosurfactant. 
     
     
         87 . The method according to  claim 85 , wherein the droplet comprises one or more molecules. 
     
     
         88 . The method according to  claim 87 , wherein the molecules are selected from the group consisting of: one or more cells, one or more virus particles, one or more bacteria, one or more beads, one or more protein molecules, one or more nucleic acid molecules, and any combination thereof. 
     
     
         89 . The method according to  claim 88 , wherein the molecules further comprise reagents for an amplification reaction. 
     
     
         90 . The method according to  claim 89 , wherein the method further comprises conducting an amplification reaction. 
     
     
         91 . The method according to  claim 90 , wherein the amplification reaction is the polymerase chain reaction. 
     
     
         92 . The method according to  claim 87 , further comprising detecting with a detector the one or more molecules in the droplet. 
     
     
         93 . The method according to  claim 92 , wherein after detecting, the method further comprising sorting the droplet. 
     
     
         94 . The method according to  claim 83 , further comprising collecting the sorted droplet. 
     
     
         95 . The method according to  claim 92 , wherein the detector is selected from the group consisting of an electrical capacity detector and an optical detector. 
     
     
         96 . The method according to  claim 95 , wherein the optical detector comprises a laser. 
     
     
         97 . The method of  claim 75 , wherein the at least one droplet is a merged droplet. 
     
     
         98 . The method according to  claim 87 , wherein the molecule is a protein, and the method further comprises conducting an enzymatic reaction. 
     
     
         99 . The method according to  claim 75 , wherein droplets of different sizes are positioned at different places in the channel. 
     
     
         100 . The method according to  claim 75 , wherein flowing is by aspiration.