Functional unit enabling controlled flow in a microfluidic device

Abstract

A microfluidic device which comprises two or more microchannel structures (set 1 ), each of which comprises a structural unit which comprises (i) one or more inlet microconduits, and (ii) an outlet microconduit downstream said one or more inlet microconduits, and (iii) a flow path for a liquid passing through either of said inlet microconduits and said outlet microconduit. The device is characterized in that each outlet microconduit in said two or more microchannel structures is a restriction microconduit. There may also be a microcavity between the inlet microconduit(s) and the restriction microconduit in each microchannel structure. Typically common flow control is used for driving a liquid flow within the device. The innovative design is useful for creating flow with low inter-channel variation with respect to the microchannel structures of the device.

1 - 22 . (canceled)  
     
     
         23 . A method of measuring an affinity complex, wherein said method comprises the steps of: 
 (i) providing a microfluidic device comprising a plurality of microchannel structures that are under common flow control, each microchannel structure comprising a reaction microcavity;    (ii) performing essentially in parallel an experiment in each of two or more of the plurality of microchannel structures, the experiment in these two or more microchannel structures comprising formation of an immobilized form of the complex and retaining under flow conditions said form within the reaction microcavity; and    (iii) measuring the presentation of the complex in said reaction microcavity in each of said two or more microchannel structures.    
     
     
         24 . The method of  claim 23 , wherein each of the microcavities of said two or more microchannel structures comprises a solid phase to which an affinity reactant which is capable of being incorporated into the affinity complex retained in step (ii) is attached.  
     
     
         25 . The method of  claim 23 , wherein 
 (a) the microfluidic device comprises a substrate having an axis of symmetry,    (b) each microchannel structure is oriented relative the axis of symmetry with an inlet port at shorter radial distance than the reaction microcavity, and    (c) the substrate is spun around its axis of symmetry to drive liquid within the microchannel structures.    
     
     
         26 . The method of  claim 23  wherein 
 a) the microfluidic device comprises a substrate having an axis of symmetry,    (b) each microchannel structure is oriented radially relative the axis of symmetry with the reaction microcavity at a larger radial distance than a substructure delivering liquid to the reaction microcavity, and    (c) the substrate is spun around its axis of symmetry to drive liquid within the microchannel structures.    
     
     
         27 . The method of  claim 23 , wherein each of the microchannel structures comprises a flow restriction downstream the reaction microcavity, which creates a pressure drop that restricts the flow through the reaction microcavity.  
     
     
         28 . The method of  claim 23 , wherein step (iii) is performed by measuring 
 (a) distribution of the complex in the reaction microcavity along the flow direction, or    (b) the total amount of the complex in the reaction microcavity.    
     
     
         29 . The method of  claim 23 , wherein step (iii) comprises measuring the total amount of the complex in the reaction microcavity.  
     
     
         30 . The method of  claim 23 , wherein each of said experiments comprises formation of an immobilized form of the complex within the reaction microcavity.  
     
     
         31 . The method of  claim 23 , wherein said experiment comprises dissociating under flow conditions an immobilized form of the complex which complex is included in the microfluidic device provided in step (i).  
     
     
         32 . The method of  claim 23 , wherein step (iii) comprises determining the distribution of the complex along the flow direction in the reaction microcavity in each of said two or more microchannel structures.  
     
     
         33 . The method of  claim 23  wherein 
 a) each microchannel structure comprises a unit for the separation of particulate matter placed upstream of the reaction microcavity, and    b) step (ii) comprises separation of particulate matter from an aliquot introduced via an inlet port.    
     
     
         34 . The method of  claim 33 , wherein 
 a) said separation unit is combined with a volume-metering unit or is upstream of a volume metering unit, and    b) step (ii) comprises performing a volume-metering step simultaneously with the separation step or upstream of the volume metering step, respectively.