Microfluidic apparatus and method for enriching and analyzing biological cells

Abstract

Integrated microfluidic devices comprising at least an enrichment channel ( 10 ) and a main electrophoretic flowpath ( 12 ) are provided. In the subject integrated devices, the enrichment channel and the main electrophoretic flowpath are positioned so that waste fluid flows away from said main electrophoretic flowpath through a discharge outlet ( 6 ). The subject devices find use in a variety of electrophoretic applications, including clinical assays, high throughput screening for genomics and pharmaceutical applications, point-or-care in vitro diagnostics, molecular genetic analysis and nucleic acid diagnostics, cell separations, and bioresearch generally.

What is claimed is:  
     
         1 . An integrated microfluidic device comprising microchannels formed in a generally planar substrate, said device comprising: 
 an enrichment microchannel comprising an enrichment channel portion containing an enrichment medium, said enrichment channel portion having a sample inlet, a discharge outlet, an elution inlet, and an enriched fraction fluid outlet;    a main electrophoretic microchannel enclosing a main electrophoretic flowpath, said main electrophoretic microchannel being connected in fluid-conducting relation to said enriched fraction fluid outlet, and said electrophoretic microchannel comprising a detection region; and    means for moving a sample into said enrichment channel portion by way of said sample inlet and out from said enrichment channel portion by way of said discharge outlet, whereby at least a fraction of a component of interest in the sample is retained by said enrichment medium;    means for moving at least a portion of the fraction out from said enrichment channel portion by way of said enriched fraction outlet and into said main electrophoretic microchannel.    
     
     
         2 . The device according to  claim 1  wherein said means for moving the component of interest out from said enrichment channel portion and into said main electrophoretic microchannel comprises a first electrode located in said enrichment channel at a point upstream from said elution inlet and a second electrode located downstream from said detection region.  
     
     
         3 . The device according to  claim 1 , further comprising a secondary microchannel connected in fluid-conducting relation between said enrichment fraction fluid outlet and said main electrophoretic microchannel.  
     
     
         4 . The device according to  claim 3  wherein said secondary microchannel encloses a secondary electrophoretic flowpath.  
     
     
         5 . The device according to  claim 3  wherein said secondary microchannel and said main electrophoretic microchannel intersect to form an injection cross.  
     
     
         6 . An integrated microfluidic device comprising microchannels formed in a generally planar substrate, said device comprising: 
 an enrichment microchannel comprising an enrichment channel portion containing an enrichment medium, said enrichment channel portion having a first inlet and a first fluid outlet;    a main electrophoretic microchannel enclosing a main electrophoretic flowpath, said main electrophoretic microchannel being connected in fluid-conducting relation to said first fluid outlet, and said main electrophoretic microchannel comprising a detection region;    means for moving a sample into said enrichment channel portion by way of said first inlet and out from said enrichment channel portion by way of said first fluid outlet, whereby at least a fraction of a component of interest in the sample is retained by said enrichment medium,    a discharge channel connected in fluid communication with said first fluid outlet at a point upstream from said main electrophoretic flowpath, for discharging a portion of said sample other than said fraction away from said main electrophoretic flowpath; and    means for moving at least a portion of the fraction out from said enrichment channel portion by way of said first fluid outlet and into said main electrophoretic microchannel.    
     
     
         7 . The device according to  claim 6 , further comprising a secondary microchannel connected in fluid conducting relation between said first fluid outlet and said main electrophoretic microchannel.  
     
     
         8 . The device according to  claim 7  wherein said secondary microchannel and said main electrophoretic microchannel intersect to form an injection cross.  
     
     
         9 . An integrated microfluidic device comprising microchannels formed in a generally planar substrate, said device comprising: 
 an enrichment microchannel comprising an enrichment channel portion containing an enrichment medium, said enrichment channel portion having a first inlet and a first fluid outlet;    a main electrophoretic microchannel enclosing a main electrophoretic flowpath, said main electrophoretic microchannel being connected in fluid-conducting relation to said first fluid outlet, and said main electrophoretic microchannel comprising a detection region;    means for moving a sample into said enrichment channel portion by way of said first inlet and out from said enrichment channel portion by way of said first fluid outlet, whereby at least a fraction of a component of interest in the sample is retained by said enrichment medium;    a discharge channel connected in fluid communication with said first fluid outlet at a point upstream from said main electrophoretic flowpath, for discharging a portion of said sample other than said fraction away from said main electrophoretic flowpath;    means for moving at least a portion of the fraction out from said enrichment channel portion by way of said first fluid outlet and into said main electrophoretic microchannel; and    a plurality of input microchannels connected in fluid relation to said first inlet, said plurality of input microchannels comprising at least a sample input microchannel and an elution input microchannel.