Microchip integrated multi-channel electroosmotic pumping system

Abstract

A microchip integrated microfabricated, microfluidic, multichannel, preferably electroosmotic pump and pumping system is disclosed. The electroosmotic pump of the invention comprises a plurality of microchannels, which begin and end in common compartments, complexed into an array. The microchannels within the pump have substantially identical, optimal dimensions of cross-section and length such that sufficient pressure for optimal flow of fluid (e.g., liquid or gas) and pressure is generated by the pump and flow rates are stable and reproducible. To effectuate efficient flow of fluid without the hindrance of backpressure, an electroosmotic pump of the invention is coupled to a single channel of a larger cross-section. A similar structure is also used in an electroosmotic valve of the invention, where samples are introduced into an analytical device. The microfluidic electroosmotic pumping system of the invention generates sufficient flow and pressures by optimizing the dimensional parameters of cross-section and length to the microchannels.

What is claimed is:  
     
         1 . A microfluidic pump or valve device comprising: 
 a substrate, said substrate comprising: 
 a plurality of first microchannels, each of said first microchannels having a first and a second end, wherein said first ends of said first microchannels originate at a common inlet compartment and wherein said second ends of said first microchannels terminate at a common outlet compartment.  
   
     
     
         2 . The microfluidic device of  claim 1 , wherein said first microchannels are open-channeled.  
     
     
         3 . The microfluidic device of  claim 1 , wherein said plurality of first microchannels comprises at least 5 microchannels.  
     
     
         4 . The microfluidic device of  claim 1 , wherein said plurality of first microchannels comprises at least 50 microchannels.  
     
     
         5 . The microfluidic device of  claim 1 , wherein said plurality of first microchannels comprises at least 100 microchannels.  
     
     
         6 . The microfluidic device of  claim 1 , wherein said plurality of first microchannels comprises at least 1,000 microchannels.  
     
     
         7 . The microfluidic device of  claim 1 , wherein said plurality of first microchannels comprises at least 10,000 microchannels.  
     
     
         8 . The microfluidic device of  claim 1 , wherein said plurality of first microchannels are in a substantially parallel configuration.  
     
     
         9 . The microfluidic device of  claim 1 , wherein said plurality of first microchannels are in a tortuous configuration.  
     
     
         10 . The microfluidic device of  claim 1 , said device further comprising an electrode embedded in said common outlet compartment.  
     
     
         11 . The microfluidic device of  claim 1 , said device further comprising an electrode embedded in said common inlet compartment.  
     
     
         12 . The microfluidic device of  claim 1 , said device further comprising an oriface connecting said inlet compartment to a surface of said substrate.  
     
     
         13 . The microfluidic device of  claim 1 , said device further comprising an oriface connecting said outlet compartment to a surface of said substrate.  
     
     
         14 . The microfluidic device of  claim 1 , said device further comprising a second microchannel coupled to said outlet compartment, wherein said second microchannel is larger in cross-section than an individual said first microchannel.  
     
     
         15 . A microfluidic system configured in a substrate, said system comprising: 
 (a) an electroosmotic pump comprising: 
 (i) a plurality of first microchannels fabricated in said substrate, each of said first microchannels having a first and a second end, wherein said first ends of said first microchannels originate at a common inlet compartment and wherein said second ends of said first microchannels terminate at a common outlet compartment; and  
 (ii) a voltage source coupled to said inlet and outlet compartments for said first microchannels;  
   (b) a second microchannel, said second microchannel having a larger cross-section than each of said plurality of first microchannels, said second microchannel having first and second ends, wherein said common outlet compartment of said first microchannels is in fluid communication with said first end of said second microchannel; and    (c) an electroosmotic valve comprising: 
 (i) two sets of a plurality of third microchannels fabricated on said substrate, said third microchannels each having a smaller cross-section than said said second channel, each of said third microchannels having a first and a second end, wherein said first ends of said first set of a plurality of third microchannels originate at a common inlet compartment, wherein said second ends of said first set of a plurality of third microchannels is in fluid communication with said second microchannel, wherein said second ends of said second set of a plurality of third microchannels is also in fluid communication with said second microchannel and wherein said first ends of said second set of a plurality of third microchannels terminate at a common outlet compartment; and  
 (vi) a voltage source coupled to said inlet and outlet compartments.  
   
     
     
         16 . The microfluidic system system of  claim 15 , wherein the ratio of the diameter of a said first microchannel to the diameter of said second microchannel is 1:1.25-1:1000.  
     
     
         17 . The microfluidic system system of  claim 15 , wherein said substrate material is selected from the group consisting of glass, quartz, silicon, polysilicon, polymeric materials (organic or inorganic) and ceramic.  
     
     
         18 . The microfluidic system system of  claim 15 , wherein said outlet compartment associated with said plurality of firsts microchannels comprises a semi-permeable gate.  
     
     
         19 . The microfluidic system system of  claim 15 , wherein said semi-permeable gate is selected from the group consisting of a porous glass, graphite, and polymeric organic or inorganic material.  
     
     
         20 . A method of transporting a material for analysis through a microchannel in a microchip, said method comprising the steps of: 
 providing in said microchip a plurality of first microchannels and a second microchannel, wherein said second microchannel has a first and a second end, wherein the cross-section of each of said first microchannels is smaller than the cross-section of said second microchannel, wherein said first end of said second microchannel is in fluid communication with said plurality of first microchannels at one end of each and wherein said second end of said second microchannel is in communication with a detection system for analysis of a sample;    introducing a sample into said second microchannel; and    applying a potential difference across a length of said plurality of microchannels to electroosmotically move said sample in said second microchannel.