Microfluidic system including a virtual wall fluid interface port for interfacing fluids with the microfluidic system

Abstract

A fluid interface port in a microfluidic system and a method of forming the fluid interface port is provided. The fluid interface port comprises an opening formed in the side wall of a microchannel sized and dimensioned to form a virtual wall when the microchannel is filled with a first liquid. The fluid interface port is utilized to perform a labeling operation on a sample.

1 . A system for performing a labeling operation, comprising: 
 a column for conveying a sample mixture through the system, wherein the column comprises an interior bounded by a side wall;    a separation region for separating the sample mixture into a plurality of bands;    a first fluid interface port downstream of the separation region for injecting labeling molecules into the interior of the column.    
     
     
         2 . The system of  claim 1 , further comprising a detector downstream of the first fluid interface port for identifying bands of the sample mixture in the column.  
     
     
         3 . The system of  claim 1 , further comprising a second fluid interface port downstream of the first fluid interface port for injecting a binding molecule into the column.  
     
     
         4 . The system of  claim 1 , further comprising an ejector for ejecting a band of the sample mixture from the column.  
     
     
         5 . The system of  claim 1 , wherein the ejector comprises a pressure pulse generator, said pressure pulse generator comprising a conical-shaped pressure chamber disposed opposite a second fluid interface port and in communication with the interior of the column and a piezo-actuated membrane connected to the pressure chamber.  
     
     
         6 . The system of  claim 1 , wherein the ejector comprises a pin assembly comprising a first pin and a second pin spaced from the first pin to define a capillary for receiving a liquid volume.  
     
     
         7 . The system of  claim 1 , further comprising a second fluid interface port formed in the side wall of the column upstream of the separation region for injecting the sample mixture into the column.  
     
     
         8 . The system of  claim 1 , wherein the fluid interface port has a diameter between about 25 μm and about 100 μm, such that when a fluid is disposed in the interior of the microchannel, the fluid forms a virtual wall at the fluid interface port.  
     
     
         9 . The system of  claim 1 , further comprising: 
 a second fluid interface port upstream of the separation region for injecting the sample mixture into the column;    a third fluid interface port downstream of the second fluid interface port for injecting a binding molecule into the column, whereby the binding molecule and the labeled molecules interact with a selected band to form a labeled band;    a detector downstream of the third fluid interface port for identifying the labeled band; and    an ejector for ejecting the labeled band from the column.