Feedback control for microfluidic cartridges

Abstract

A device for sensing fluid movement within a microfluidic channel which uses feedback to control its operation. The device measures electric parameters to interpret fluidic parameters such as flow speed, and the presence or absence of fluid within the channel.

What is claimed is:  
     
         1 . A microfluidic device, comprising: 
 a microfluidic channel having an inlet and an outlet;    means associated with said channel and located between said inlet and said outlet, for sensing fluid flow within said channel, and generating electrical signals corresponding to fluidic properties of the fluid flow;    and means, coupled to said sensing means, for controlling fluid flow through said channel as a result of information obtained from said electrical signals from said sensing means.    
     
     
         2 . The device of  claim 1 , wherein said sensing means comprises an electrode assembly.  
     
     
         3 . The device of  claim 2 , wherein said electrode assembly includes a plurality of electrodes.  
     
     
         4 . The device of  claim 1 , wherein said sensing means is positioned within said microfluidic channel.  
     
     
         5 . The device of  claim 1 , wherein said control means further comprises: 
 means for analyzing said electrical signals from said sensing means, and    means for pumping a fluid into the inlet of said microfluidic channel in response to commands from said analyzing means.    
     
     
         6 . The device of  claim 1 , wherein said sensing means comprises an optical detector.  
     
     
         7 . The device of  claim 1 , wherein said optical detector is located in close proximity to said microfluidic channel.  
     
     
         8 . The device of  claim 7 , wherein said optical detector comprises a light source located on one side of said channel and a light detector located on the other side of said channel such that the light from said source may be altered by the presence or absence of a liquid in said channel.  
     
     
         9 . The device of  claim 1 , wherein said sensing means is capable of detecting wetout in said channel.  
     
     
         10 . The device of  claim 1 , wherein said sensing means is capable of detecting the presence of a liquid within said channel.  
     
     
         11 . The device of  claim 1 , wherein said sensing means is capable of detecting the presence of a gas within said channel.  
     
     
         12 . The device of  claim 2 , wherein said electrode assembly is located within said channel and is capable of detecting the flow speed of fluids flowing within said channel.  
     
     
         13 . The device of  claim 5 , wherein said pumping means is capable of changing the flow rate of a fluid within said channel in response to a command from said analyzing means.  
     
     
         14 . The device of  claim 1 , wherein said sensing means is capable of detecting a meniscus of a liquid flowing within said microfluidic channel.  
     
     
         15 . The device of  claim 1 , wherein said sensing means comprises a hot wire anemometer.  
     
     
         16 . The device of  claim 5 , wherein said pumping means is capable of stopping a fluid from flowing within said channel in response to a signal from said analyzing means.  
     
     
         17 . The device of  claim 5 , wherein said analyzing means includes a computer link.  
     
     
         18 . The device of  claim 1 , wherein said fluidic properties include conductivity.  
     
     
         19 . The device of  claim 1 , wherein said fluidic properties include capacity.