Systems and methods for monitoring the amplification and dissociation behavior of dna molecules

Abstract

The present invention relates to systems and methods for monitoring the amplification of DNA molecules and the dissociation behavior of the DNA molecules. A method according to one embodiment of the invention may include the steps of: forcing a sample of a solution containing real-time PCR reagents to move though a channel; and while the sample is moving through an analysis region of the channel, performing the steps of: (a) cycling the temperature of the sample until the occurrence of a predetermined event; (b) after performing step (a), causing the sample's temperature to gradually increase from a first temperature to a second temperature; and (c) while the step of gradually increasing the sample's temperature is performed, using an image sensor to monitor emissions from the sample.

What is claimed is: 
     
         1 . An optical analysis system, comprising:
 a substrate comprising a microfluidic channel;   a thermal generating unit operable to provide heat to and absorb heat from at least a portion of the microfluidic channel;   an image sensor disposed in relation to the substrate such that said portion of the channel is within the field of view of the image sensor; and   an image processing system coupled to the image sensor and configured to: (i) receive image data from the image sensor and (ii) use image data from the image sensor to determine whether (a) the intensity of emissions from a nucleic acid sample traveling through said portion of the channel equals or exceeds a predetermined emission intensity threshold or (b) the rate of change in the intensity of emissions from the nucleic acid sample traveling through said portion of the channel equals or is less than a predetermined threshold; and   a temperature controller configured to control the thermal generating unit and configured to cause the thermal generating unit to gradually ramp the temperature of the portion of the channel from a first temperature to a second temperature in response to the image processing system determining that (a) the intensity of emissions from a nucleic acid sample traveling through said portion of the channel equals or exceeds a predetermined emission intensity threshold or (b) the rate of change in the intensity of emissions from the nucleic acid sample equals or is less than the predetermined threshold.   
     
     
         2 . The system of  claim 1 , wherein the temperature controller is further configured to cause the thermal generating unit to cycle the temperature of the portion of the channel in response to a predetermined input. 
     
     
         3 . The system of  claim 2 , further comprising an image sensor controller, wherein the image sensor controller is operable to cause the image sensor to capture images of at least a segment of said portion of the channel that is within the field of view of the image sensor while the thermal generating unit cycles the temperature of the portion of the channel. 
     
     
         4 . The system of  claim 3 , wherein the image sensor controller is operable to cause the image sensor to capture images of at least a segment of said portion of the channel that is within the field of view of the image sensor while the thermal generating unit ramps the temperature of the portion of the channel. 
     
     
         5 . The system of  claim 4 , wherein the image sensor controller is operable to cause the image sensor to capture at least 1 image every 90 seconds of at least a segment of said portion of the channel that is within the field of view of the image sensor while the thermal generating unit cycles the temperature of the portion of the channel. 
     
     
         6 . The system of  claim 5  wherein the image sensor controller is operable to cause the image sensor to capture at least 5 images per second of at least a segment of said portion of the channel that is within the field of view of the image sensor while the thermal generating unit ramps the temperature of the portion of the channel. 
     
     
         7 . The system of  claim 6 , wherein the thermal generating unit is configured to ramp the temperature of the portion of the channel by steadily increasing the amount of heat provided to the portion of the channel at a thermal ramp rate of between about 0.1 to 2 degree Celsius (C) per second. 
     
     
         8 . The system of  claim 1 , further comprising an excitation source for producing electromagnetic radiation directed at the portion of the channel. 
     
     
         9 . The system of  claim 8 , further comprising a second excitation source for illuminating at least a segment of the portion of the channel in response to the image processing system determining that (a) the intensity of emissions from a nucleic acid sample traveling through said portion of the channel equals or exceeds a predetermined emission intensity threshold or (b) the rate of change in the intensity of emissions from the nucleic acid sample equals or is less than the predetermined threshold. 
     
     
         10 . The system of  claim 9 , wherein the image sensor is a CMOS image sensor and the second excitation source is a laser.