Isolating Microfluidic Structures and Trapping Bubbles

Abstract

Some configurations of a microfluidic apparatus can comprise a fluidic circuit of interconnected fluidic structures into which a plurality of different media can be introduced or extracted. A variety of operations can be performed with the different media including isolating with a second medium one or more of the fluidic structures that is filled partially or fully with a first medium. Discrete volumes of a medium can be moved through the isolating second medium to deliver materials or micro-objects to or remove micro-objects or materials from a fluidic structure that is otherwise isolated by the second medium. Some configurations of a microfluidic apparatuses can isolate microfluidic structures in a microfluidic apparatus using flow rates or blocking structures, and some configurations can manage bubbles in fluidic structures.

1 . A microfluidic apparatus comprising:
 a flow region comprising a fluidic channel configured to direct fluid flow;   at least two pens, each pen having a fluidic interface with said channel; and wherein said fluidic channel is configured to fluidically isolate a first pen from a second pen by reducing diffusion of soluble components from said first pen into said second pen.   
     
     
         2 . The microfluidic apparatus of  claim 2 , wherein said fluidic interface of said first pen is upstream from said fluidic interface of said second pen along said fluidic channel. 
     
     
         3 . The microfluidic apparatus of  claim 1 , wherein a length of said fluidic channel between said first pen and said second pen is at least 50% longer than a linear distance between said fluidic interface of said first pen and said fluidic interface of said second pen. 
     
     
         4 . The microfluidic apparatus of  claim 1 , wherein a length of said fluidic channel between said first pen and said second pen is at least twice as long as a linear distance between said fluidic interface of said first pen and said fluidic interface of said second pen. 
     
     
         5 . The microfluidic apparatus of  claim 1 , wherein a length of said fluidic channel between said first pen and said second pen is in a range of at least twice to about ten times as long as a linear distance between said fluidic interface of said first pen and said fluidic interface of said second pen. 
     
     
         6 . The microfluidic apparatus of  claim 1 , wherein said fluidic channel is serpentine. 
     
     
         7 . The microfluidic apparatus of  claim 1 , wherein said fluidic channel is interrupted by at least one interface with a minor fluidic channel having a non-parallel direction to said fluidic channel. 
     
     
         8 . The microfluidic apparatus of  claim 7 , wherein a width of said minor fluidic channel is about 10% of a width of the fluidic channel. 
     
     
         9 . The microfluidic apparatus of  claim 7 , wherein a width of said minor fluidic channel is about 10% to about 50% of a width of the fluidic channel. 
     
     
         10 . The microfluidic apparatus of  claim 8 , wherein said fluidic channel is serpentine and has a length between said first pen and said second pen in a range of at least twice to about five times as long as the linear distance between said fluidic interface of said first pen and said fluidic interface of said second pen. 
     
     
         11 . A process of operating a microfluidic apparatus, wherein the microfluidic apparatus comprises a flow region comprising a fluidic channel, and at least two pens, wherein each of said pens has a fluidic interface with said fluidic channel, the process comprising:
 flowing a first fluidic medium along said fluidic channel; and,   fluidically isolating a first pen of said at least two pens from a second pen of said at least two pens by reducing diffusion of soluble components from said first pen into said second pen.   
     
     
         12 . The process of  claim 11 , wherein the microfluidic apparatus is the apparatus of  claim 1 . 
     
     
         13 . The process of  claim 11 , wherein flowing said first fluidic medium along said fluidic channel comprises flowing said first fluidic medium past said fluidic interface of said first pen and,
 subsequently, past said fluidic interface of said second pen.   
     
     
         14 . The process of  claim 11 , wherein said diffusion of soluble components is substantially reduced. 
     
     
         15 . The process of  claim 11 , wherein fluidically isolating said first pen from said second pen further comprises flowing a second fluidic medium along said fluidic channel; and,
 displacing said first fluidic medium.   
     
     
         16 . The process of  claim 15 , wherein said second fluidic medium is substantially immiscible with said first fluidic medium. 
     
     
         17 .- 42 . (canceled) 
     
     
         43 . A process of operating a microfluidic apparatus, said process comprising:
 introducing a first volume of a first medium into a first fluidic structure and a second fluidic structure, wherein said second fluidic structure is fluidically connected to said first fluidic structure; and,   isolating said second fluidic structure from said first fluidic structure.   
     
     
         44 . The process of  claim 43 , wherein:
 said first fluidic structure is a fluidic channel; and,   said second fluidic structure is a pen comprising an opening connected to said channel.   
     
     
         45 . The process of  claim 43 , wherein said isolating comprises disposing a volume of a second medium at a first fluidic interface between said first fluidic structure and said second fluidic structure, said first medium remaining in said second fluidic structure. 
     
     
         46 . The process of  claim 45 , further comprising: loading a biological micro-object into said second fluidic structure. 
     
     
         47 . The process of  claim 46 , further comprising: culturing said biological micro-object in said second fluidic structure. 
     
     
         48 .- 81 . (canceled)