Methods and Devices to Control Fluid Volumes, Reagent and Particle Concentration in Arrays of Microfluidic Drops

Abstract

A microfluidic device includes a substrate comprising an inlet in fluid communication with one or more conduits and one or more parking loops in fluid communication with the one or more conduits. Each parking loop includes a bypass channel and a lower branch with a fluidic trap capable of retaining one or more drops of a sample solution, wherein the bypass channel has a smaller hydrodynamic resistance than the lower branch within the fluidic trap and a hydrodynamic resistance ratio (R T /R B ) between the lower branch within the fluidic trap and the bypass channel is from 1.5 to 3.2. One or more outlets are in fluid communication with at least one of the bypass channels. A method for making the microfluidic device is also disclosed.

What is claimed is: 
     
         1 . A microfluidic device comprising:
 a substrate comprising an inlet in fluid communication with one or more conduits;   one or more parking loops in fluid communication with the one or more conduits, each parking loop comprising a bypass channel and a lower branch with a fluidic trap capable of retaining one or more drops of a sample solution, wherein the bypass channel has a smaller hydrodynamic resistance than the lower branch within the fluidic trap and a hydrodynamic resistance ratio (R T /R B ) between the lower branch within the fluidic trap and the bypass channel is from 1.5 to 3.2; and   one or more outlets in fluid communication with at least one of the bypass channels.   
     
     
         2 . The device of  claim 1 , further comprising a cartridge connected to the inlet, wherein the cartridge is configured to introduce the sample into the one or more conduits and the one or more fluidic traps. 
     
     
         3 . The device of  claim 1 , wherein the hydrodynamic resistance ratio (R T /R B ) between the lower branch and the bypass channel is from 1.0 to 2.0. 
     
     
         4 . The device of  claim 1 , wherein a hydrodynamic resistance ratio (R T /R B ) between the lower branch and the bypass channel is from 1.4 to 1.6. 
     
     
         5 . The device of  claim 1 , wherein the one or more parking loops comprise an array of parking loops. 
     
     
         6 . The device of  claim 5 , wherein the array of parking loops is formed into at least one of a square array, a triangular array, a pentagonal array, a hexagonal array, a rectangular array, a polygonal array, a circular array, an oval array, an undular array, or a three-dimensional array. 
     
     
         7 . The device of  claim 5 , wherein the array of parking loops is in series. 
     
     
         8 . The device of  claim 1 , wherein the microfluidic device is adapted to separate blood or other cells. 
     
     
         9 . The device of  claim 1 , further comprising a reagent inlet and a mixing channel in fluid communication with a T-junction in fluid connection with the one or more outlets from the one or more bypass channels. 
     
     
         10 . The device of  claim 1 , wherein the one or more parking loops are in fluid communication with at least one of the following additional reservoirs: mixing tubes, concentrator arrays, conduits, outlets, reagent reservoirs, valves, particle segregators, filters, plugs, or pumps. 
     
     
         11 . The device of  claim 1 , wherein the fluidic trap is wider than the one or more conduits or the bypass channel. 
     
     
         12 . The device of  claim 1 , further comprising a side channel in fluid communication with a T-junction in fluid communication with the one or more outlets from the one or more bypass channels and an outlet channel. 
     
     
         13 . A method of making a microfluidic device comprising:
 forming one or more parking loops in fluid communication with the one or more conduits in a first substrate, wherein each parking loop comprising a bypass channel and a lower branch with a fluidic trap capable of retaining one or more drops of a sample solution, the bypass channel has a smaller hydrodynamic resistance than the lower branch within the fluidic trap, and a hydrodynamic resistance ratio (R T /R B ) between the lower branch within the fluidic trap and the bypass channel is from 1.5 to 3.2;   creating an inlet in fluid communication with the one or more conduits and one or more outlets in fluid communication with at least one of the bypass channels; and   forming the microfluidic device by bonding the first substrate with a second substrate.   
     
     
         14 . The method of  claim 13 , wherein the hydrodynamic resistance ratio (R T /R B ) between the lower branch and the bypass channel is from 1.0 to 2.0. 
     
     
         15 . The method of  claim 13 , wherein a hydrodynamic resistance ratio (R T /R B ) between the lower branch and the bypass channel is from 1.4 to 1.6. 
     
     
         16 . The method of  claim 13 , wherein the one or more parking loops comprise an array of parking loops. 
     
     
         17 . The method of  claim 16 , wherein the array of parking loops formed into at least one of a square array, a triangular array, a pentagonal array, a hexagonal array, a rectangular array, a polygonal array, a circular array, an oval array, an undular array, or a three-dimensional array. 
     
     
         18 . The method of  claim 16 , wherein the array of parking loops is in series. 
     
     
         19 . The method of  claim 13 , wherein the device is adapted to separate blood or other cells. 
     
     
         20 . The method of  claim 13 , further comprising forming a reagent inlet and a mixing channel in fluid communication with a T-junction in fluid connection with the one or more outlets from the one or more bypass channels. 
     
     
         21 . The method of  claim 13 , further comprising forming at least one of the following additional reservoirs in fluid communication with the one or more parking loops: mixing tubes, concentrator arrays, conduits, outlets, reagent reservoirs, valves, particle segregators, filters, plugs, or pumps. 
     
     
         22 . The method of  claim 13 , wherein the fluidic trap is wider than the one or more conduits or the bypass channel. 
     
     
         23 . The method of  claim 13 , further comprising forming a side channel in fluid communication with a T-junction in fluid communication with the one or more outlets from the one or more bypass channels and an outlet channel. 
     
     
         24 . The method of  claim 13 , further comprising using a mold to form the one or more parking loops in fluid communication with the one or more conduits in the first substrate. 
     
     
         25 . The method of  claim 13 , further comprising treating the one or more parking loops and the one or more conduits.