Microfluidic device for concentrating particles in a concentrating solution

Abstract

A microfluidic device for concentrating particles in a concentrating solution. A sample and a concentrating fluid flow laminarly with a microfluidic channel wherein the concentrating fluid is formulated such that it extracts fluid from the sample and thus concentrates the particles in the sample.

1 - 7 . (canceled)  
     
     
         8 . A method for increasing the concentration of particles in a sample fluid, the sample fluid comprising the particles and solvent molecules, the method comprising: 
 providing a microfluidic device comprising a first inlet channel, a second inlet channel, and a main diffusion channel connected to the first and second inlet channels;    flowing the sample fluid through the first inlet channel into the main diffusion channel;    flowing a concentrating fluid through the second inlet channel into the main diffusion channel; and    flowing the sample fluid and concentrating fluid in laminar flow through the main diffusion channel, such that a fluid interface is formed between the sample fluid and the concentrating fluid, and solvent molecules diffuse across the fluid interface from the sample fluid into the concentrating fluid thereby increasing the concentration of the particles in the sample fluid.    
     
     
         9 . The method of  claim 8  wherein the concentrating fluid comprises ionic particles.  
     
     
         10 . The method of  claim 9  wherein the ionic particles have a larger size than the solvent molecules.  
     
     
         11 . The method of  claim 8  wherein the concentrating solution comprises an immiscible solution with a chemical affinity for the solvent molecules.  
     
     
         12 . The method of  claim 8  wherein the average flow speeds of the sample fluid and the concentrating fluid are different.  
     
     
         13 . The method of  claim 8  wherein the sample fluid and the concentrating fluid are immiscible.