Formation of a microfluidic array

Abstract

The invention relates to a method of forming a microfluidic array comprising at least one channel of semi-circular section, comprising the following steps: bringing into contact a first liquid ( 7 ) with an array of electrodes ( 3 ) of a microfluidic chip ( 1 ) comprising at least one pair of substantially parallel and coplanar electrodes ( 3 a, 3 b ) arranged on a substrate ( 4 ), activating said array of electrodes so as to actuate by liquid dielectrophoresis LDEP said first liquid to form a fluidic structure ( 9 ) comprising at least one fluidic finger ( 9 a ), and using said fluidic structure as a mould to form said microfluidic array by solidification or hardening of a second liquid ( 11 ) deposited on the microfluidic chip and hugging the shape of said fluidic structure.

1 . Method of forming a microfluidic array comprising at least one channel of semi-circular section, characterised in that it comprises the following steps:
 bringing into contact a first liquid ( 7 ) with an array of electrodes ( 3 ) of a microfluidic chip ( 1 ) comprising at least one pair of substantially parallel and coplanar electrodes ( 3   a,    3   b ) arranged on a substrate ( 4 ),   activating said array of electrodes so as to actuate by liquid dielectrophoresis LDEP said first liquid to form a fluidic structure ( 9 ) comprising at least one fluidic finger ( 9   a ), and   using said fluidic structure as a mould to form said microfluidic array by solidification or hardening of a second liquid ( 11 ) deposited on the microfluidic chip and hugging the shape of said fluidic structure.   
     
     
         2 . Method according to  claim 1 , characterised in that said first liquid ( 7 ) has a property of hardening and in that said method comprises the following steps:
 hardening said first liquid materialising said fluidic structure ( 9 ) while maintaining the array of electrodes ( 3 ) in activation during the step of hardening in order to congeal said fluidic structure, and   flowing the second liquid ( 11 ) onto said congealed fluidic structure.   
     
     
         3 . Method according to  claim 2 , characterised in that the first liquid ( 7 ) is a liquid-solid phase change material selected from the following materials: epoxy, silicone or resin based adhesive, UV adhesive, gel, cross-linking polymer, paraffin, agarose, gelatine, beeswax, and wax. 
     
     
         4 . Method according to  claim 3 , characterised in that the first liquid ( 7 ) is a UV adhesive and in that the hardening of said first liquid is carried out by exposure to UV radiation at a wavelength adapted to the cross-linking wavelength of said UV adhesive. 
     
     
         5 . Method according to  claim 4 , characterised in that it comprises a step of melting the hardened or solidified material of said first liquid in order to reconfigure the fluidic structure. 
     
     
         6 . Method according to  claim 1 , characterised in that the second liquid ( 11 ) is not miscible with the first liquid ( 7 ) such that the interface between the two liquids takes the shape of said fluidic structure ( 9 ) under the effect of the activation of said array of electrodes, the first liquid being covered with the second liquid. 
     
     
         7 . Method according to  claim 6 , characterised in that the first liquid ( 7 ) is deionised water DIW, water, an organic liquid, a solvent, or an aqueous solution. 
     
     
         8 . Method according to  claim 1 , characterised in that the second liquid ( 11 ) is a liquid-solid phase change material selected from the following materials: cross-linking polymers, paraffin, agarose, gelatine, beeswax, wax, epoxy, silicone or resin based adhesive, UV adhesive, and gel. 
     
     
         9 . Method according to  claim 1 , characterised in that the geometry of the microfluidic array is programmable by the activation of the electrodes in an independent manner. 
     
     
         10 . Method according to  claim 1 , characterised in that the shape and/or the dimensions of said at least one fluidic finger ( 9   a ) of the microfluidic array is configurable depending on the shape and/or the width and/or the number of electrodes. 
     
     
         11 . Method according to  claim 1 , characterised in that in the course of a same actuation by liquid dielectrophoresis, said at least one fluidic finger is able to be formed with variable dimensions. 
     
     
         12 . Method according to  claim 1 , characterised in that said microfluidic array is used as a model plate to form other microfluidic arrays. 
     
     
         13 . Method of forming a microfluidic array comprising at least one channel of semi-circular section, characterised in that it comprises the following steps:
 placing a mother drop of a first liquid ( 7 ) having a property of hardening on an initial position of an array of electrodes ( 3 ) comprising at least one pair of substantially parallel and coplanar electrodes arranged on a substrate of a microfluidic chip,   activating said array of electrodes so as to actuate by liquid dielectrophoresis LDEP said first liquid to form a fluidic structure ( 9 ) comprising at least one fluidic finger,   hardening said first liquid materialising said fluidic structure while maintaining the array of electrodes in activation in order to congeal said fluidic structure,   flowing a second liquid ( 11 ) onto the microfluidic chip covering said congealed fluidic structure,   hardening the second liquid to form the microfluidic array, and   removing the microfluidic array from the mould.   
     
     
         14 . Method of forming a microfluidic array comprising at least one channel of semi-circular section, characterised in that it comprises the following steps:
 placing non-miscible first and second liquids ( 7 ,  11 ) on a free surface of a microfluidic chip comprising an array of electrodes ( 3 ) having at least one pair of substantially parallel and coplanar electrodes, the second liquid ( 11 ) having a property of hardening,   activating said array of electrodes so as to actuate by liquid dielectrophoresis LDEP said first liquid to form a fluidic structure comprising at least one fluidic finger ( 9   a ), the interface between the first and second liquids taking the shape of said fluidic structure,   hardening said second liquid covering said fluidic structure while maintaining the array of electrodes in activation such that the impression of the fluidic structure is replicated in the second hardened liquid thereby forming the fluidic array, and   disbonding the microfluidic array from the microfluidic chip.   
     
     
         15 . Method of forming a microfluidic component using the microfluidic array formed according to  claim 1 , characterised in that it comprises the following steps:
 assembling the microfluidic array ( 13 ) to a support ( 23 ) to form a microfluidic component ( 25 ), and   forming at least one hole ( 26   a ) in said assembly to create a fluidic input.