Microfluidic Flow Monitoring

Abstract

The present invention relates to systems and methods of monitoring velocity or flow in channels, especially in microfluidic channels. In some embodiments, the present invention relates to systems and methods of monitoring velocity or flow rate in systems and methods for performing a real-time polymerase chain reaction (PCR) in a continuous-flow microfluidic system.

1 . A system for monitoring a solution flow in a microfluidic channel comprising:
 (a) a chip comprising at least one microfluidic channel;   (b) a fluid movement system for moving a fluid through the channel to fill the at least one channel with a solution and stop the solution flow;   (c) a flow marker introduction system for introducing a flow marker into the channel;   (d) an illumination system for generating at least two measuring points; and   (e) a detection system for measuring the movement of the flow marker within the channel between the at least two measuring points.   
     
     
         2 . The system of  claim 1 , wherein the illumination system generates the at least two measuring points from one light source by backside reflection. 
     
     
         3 . The system of  claim 2 , wherein light source is laser. 
     
     
         4 . The system of  claim 2 , wherein light source is an LED. 
     
     
         5 . The system of  claim 1 , wherein the microfluidic channel comprises a flow measuring region. 
     
     
         6 . The system of  claim 5 , wherein at least a portion of the flow measuring region of the microfluidic channel is narrower compared to the remainder of the channel. 
     
     
         7 . The system of  claim 1 , wherein said fluid movement system includes a pump or a vacuum. 
     
     
         8 . The system of  claim 1 , wherein said flow marker introduction system includes a piezoelectric nozzle, a bubble jet head, a sipper, a converging inlet channel comprising a value or a directed energy source. 
     
     
         9 . The system of  claim 1 , wherein the flow marker is selected from the group consisting of a bubble, a semiconductor quantum dot, a polymer microbead, a fluorescent particle, a dye slug and a scattering metal particle. 
     
     
         10 . The system of  claim 1 , wherein the microfluidic channel has a width of about 5 microns to about 500 microns and a depth of about 1 micron to about 100 microns. 
     
     
         11 . The system of  claim 10 , wherein the microfluidic channel has a width of about 20 microns to about 400 microns and a depth of about 5 microns to about 50 microns. 
     
     
         12 . The system of  claim 10 , wherein the microfluidic channel has a width of about 30 microns to about 250 microns and a depth of about 10 microns to about 20 microns. 
     
     
         13 . The system of  claim 10 , wherein the microfluidic channel has a width of about 150 microns and a depth of about 10 microns. 
     
     
         14 . The system of  claim 6 , wherein the microfluidic channel in the flow measuring region has a width of about 5 microns to about 400 microns and a depth of about 1 micron to about 100 microns. 
     
     
         15 . The system of  claim 14 , wherein the microfluidic channel in the flow measuring region has a width of about 10 microns to about 200 microns and a depth of about 5 microns to about 50 microns. 
     
     
         16 . The system of  claim 14 , wherein the microfluidic channel in the flow measuring region has a width of about 20 microns to about 100 microns and a depth of about 10 microns to about 20 microns. 
     
     
         17 . The system of  claim 14 , wherein the microfluidic channel in the flow measuring region has a width of about 40 microns and a depth of about 10 microns. 
     
     
         18 . (canceled) 
     
     
         19 . The system of  claim 18 , wherein the computer also controls a data acquisition rate for detecting the movement of the flow marker. 
     
     
         20 - 45 . (canceled) 
     
     
         46 . The system of  claim 1 , further comprising a thermal system to thermally cycle a length of the at least one channel to perform a PCR reaction on the solution flow when the solution flow is stopped. 
     
     
         47 . The system of  claim 1 , further comprising a thermal system to thermally cycle a length of the at least one channel to perform a PCR reaction on the solution flow when the solution flow is stopped, wherein the PCR reaction is followed by a melt analysis performed on the stopped solution flow. 
     
     
         48 . The system of  claim 46 , wherein the fluid movement system is configured to move the solution flow following the PCR reaction.