Systems and methods for detecting and analyzing polymers

Abstract

A detection system and methods for improving the ability of the detection system to recognize labels that are disposed on a polymer. Embodiments of the invention include schemes for selecting emitters and labels used within the system in a manner that allows an increase in the number of distinct labels that can be used together in a system. In other embodiments, the detection system and methods are directed to identifying portions of a detection signal that may be associated with extra labels residing within a detection zone. In other embodiments, the detection system and methods relate to using wide field imaging detectors while reducing out of focus noise contributions to detection signals of the system. Still, other embodiments relate to the use of linear array detectors to detect labels

1 . A detection system for analyzing a polymer, the detection system comprising:
 a first detection zone disposed in a first area of a microchannel and adapted to detect a polymer having first and second polymer portions to create a first detection signal when the polymer is in the first zone;   a second detection zone disposed in a second area of the microchannel that is different from the first area, the second detection zone adapted to detect the second polymer portion to create a second detection signal when the second portion is in the second area;   a data processor adapted to comparing the first and second detection signals and identify components that are not common to both the first and second detection signals.   
     
     
         2 . The detection system of  claim 1 , wherein the second detection zone is substantially overlapped with the first detection zone. 
     
     
         3 . The detection system of  claim 2 , wherein the first detection zone and the second detection zone are substantially circular, the second detection zone being concentric with the first detection zone and the second detection zone being disposed entirely within the first detection zone. 
     
     
         4 . The detection system of  claim 3 , wherein the first detection zone has a diameter of approximately 1.00 microns and the second detection zone has a diameter of approximately 0.50 microns. 
     
     
         5 . The detection system of  claim 1 , further comprising:
 an emitter for illuminating the first detection zone, the emitter adopted to emit on excitation signal having low intensity components and high intensity components.   
     
     
         6 . The detection system of  claim 5 , wherein the first detection zone covers areas having both low and high intensity components of the excitation signal while the second detection zone covers areas having substantially only high intensity components of the excitation signal. 
     
     
         7 . The detection system of  claim 6 , wherein the data processor is adapted to remove at least some portions of emission signals associated with the first detection zone of the low intensity components of the excitation signal from the first detection signal to improve the identification of the second polymer portion by the first detection signal. 
     
     
         8 . The detection system of any of  claim 1 , wherein the polymer is a nucleic acid. 
     
     
         9 . The detection system of  claim 8 , wherein the polymer is DNA or RNA. 
     
     
         10 . The detection system of  claim 9 , wherein the polymer is genomic DNA. 
     
     
         11 . The detection system of  claim 9 , wherein the RNA comprises miRNA, siRNA, or RNAi. 
     
     
         12 . The detection system of  claim 1 , wherein the first and second detection zones are adapted to detect a polymer or polymer portion having a label that fluoresces. 
     
     
         13 . The detection system of  claim 1 , wherein the polymer comprises a plurality of polymers, each of the first and second polymer portions comprising separate polymers. 
     
     
         14 . A method of analyzing a polymer in a detection system, the method comprising:
 passing a plurality of polymers comprising a first polymer portion and a second polymer portion through a first detection zone to create a first detection signal, the first detection zone disposed in a first area of the microchannel;   passing the second portion of polymers through a second detection zone to create a second detection signal, the second detection zone disposed in a second area of the microchannel;   identifying components of the first detection signal that are associated with the second polymer portion by comparing the first detection signal with the second detection signal; and   detecting components of the first detection signal associated with the second polymer portion to analyze the polymers.   
     
     
         15 . The method of  claim 14 , further comprising:
 modifying the first detection signal by removing components of the first detection signal that are not also associated only with the second detection signal to improve the identification of the second polymer portion by the first detection signal.   
     
     
         16 . The method of  claim 14 , wherein passing the plurality of polymers comprises moving both the first detection zone and the second detection zone relative to the first and second portion of polymers. 
     
     
         17 . The method of  claim 14 , wherein passing the plurality of polymers comprises flowing the plurality of polymers within a fluid through the microchannel. 
     
     
         18 . The method of  claim 14 , wherein the polymer is a nucleic acid. 
     
     
         19 . The method of  claim 18 , wherein the polymer is DNA or RNA. 
     
     
         20 . The method of  claim 19 , wherein the polymer is genomic DNA. 
     
     
         21 . The method of  claim 19 , wherein the RNA is miRNA, siRNA, or RNAi. 
     
     
         22 . The method of  claim 14 , wherein passing the second portion of polymers through the second detection zone comprises passing the second portion of polymers through the second detection zone that is completely overlapped with the first detection zone. 
     
     
         23 . The method of  claim 14 , wherein passing a plurality of polymers through the first detection zone comprises passing a plurality of polymers through the first detection zone defined by a high intensity region and a low intensity region; and
 further wherein passing the second portion of polymers through the second detection zone comprises passing the second portion of the polymer through the second detection zone that does not include the low intensity region.   
     
     
         24 . The method of  claim 14 , wherein identifying the components of the first detection signal that are associated with the second polymer portion comprises comparing a histogram of signal intensities for the first detection signal with a histogram of signal intensities for the second detection signal. 
     
     
         25 . The method of  claim 14 , wherein modifying the first detection signal comprises removing low intensity components from the first detection signal that are not also present in second detection signal. 
     
     
         26 . The method of  claim 14 , wherein passing a plurality of polymers through a first detection zone comprises passing a plurality of polymers through a circular detection zone having a diameter of approximately 1.00 microns; and
 further wherein, passing the second portion of polymers through a second detection zone comprises passing a plurality of polymers through a second circular detection zone having a diameter of approximately 0.50 microns and being substantially centered within the first detection zone.