Method and device for rapid color detection

Abstract

Methods and apparatus are provided for miniaturized DNA sequencing using four-color detection. The method employs a multichannel chip where the channels are simultaneously irradiated to excite fluorophores in the channels. The emitted light is divided into four different wavelength beams and read by CCDs. The results are multiplexed for rapid sequencing of a large number of samples, with high fidelity of the sequences.

What is claimed is:  
     
         1 . In a method for rapidly detecting light from a channel of capillary dimensions, where a plurality of individual components of a mixture move along said channel at spaced apart intervals for an exposure time of less than about 500 msec, where the light appears as a band, and is scanned by an optical fiber, the improvement which comprises: 
 detecting the light from each of said bands with a CCD camera, where the light illuminates a spot which includes from 2 to 8 pixels in a row and binning the signal received along the rows of pixels to provide a total signal for said band; and    transmitting the signal to a data processor for detecting said band.    
     
     
         2 . A method according to  claim 1 , wherein the rate of scanning is at least about 10 Hz.  
     
     
         3 . A method according to  claim 1 , wherein said CCD camera has a quantum efficiency of at least 85%.  
     
     
         4 . A method according to  claim 1 , wherein said individual components comprise four different fluorophores emitting at four different wavelengths, said method further comprising: 
 dividing the light from said bands into four different wavelength ranges; and    separately detecting each wavelength range with a separate CCD camera.    
     
     
         5 . A method for performing DNA sequencing detecting four different fluorophores emitting at four different wavelengths, said method comprising: 
 moving electrophoretically a mixture of fluorophore-labeled oligonucleotides at a rate to provide an exposure time of less than about 500 msec to detection and at a spacing between oligonucleotides in the range of about 50 to 200 μm;    irradiating said fluorophore-labeled at a detection site with excitation light to produce bands of emitted light;    dividing the light from said bands into four different wavelength ranges; and    detecting the light from each of said bands with a CCD camera, where the light illuminates a spot which includes from 2 to 8 pixels in a row and binning the signal received along the rows of pixels to provide a total signal for said band.    
     
     
         6 . A method according to  claim 5 , wherein said moving electrophoretically is in a channel of from about 50 to 20,000μ 2  cross-section under a voltage in the range of about 500 to 4000V.  
     
     
         7 . A method according to  claim 6 , wherein said channel is in a poly(methyl methacrylate substrate and said channel contains linear polyacrylamide as a sieving agent.  
     
     
         7 . A method according to  claim 6 , wherein said fluorophore labels are dR110, dR6G, dROX and dTAMRA.  
     
     
         8 . A method according to  claim 6 , wherein said DNA is at least 500 nucleotides.  
     
     
         9 . A method according to  claim 6 , wherein said binning is of 8 to 36 pixels.  
     
     
         10 . A method for performing DNA sequencing detecting four different fluorophores emitting at four different wavelengths, said method comprising: 
 moving electrophoretically, in a channel having a cross-section in the range of from about 50 to 20,000μ 2 , a mixture of fluorophore-labeled oligonucleotides at a rate to provide an exposure time of less than about 500 msec to detection and at a spacing between oligonucleotides in the range of about 50 to 200 μm; irradiating said fluorophore-labeled at a detection site with an argon laser to produce bands of emitted light;    dividing the light from said bands into four different wavelength ranges; and    detecting the light from each of said bands with a CCD camera, where the light illuminates a spot which includes from 2 to 8 pixels in a row and binning the signal received along the rows of pixels of from 8 to 36 pixels to provide a total signal for said band.    
     
     
         11 . A method of irradiating a plurality of channels in a solid substrate substantially transparent to a wavelength range of interest, using said solid substrate where a plurality of channels are bordered by reflective channels as a result of the difference in refractive index between the solid substrate and the material in the reflective channel, one reflective channel having a first wall which at the angle of the incident light transmits the light orthogonally through said channels, and the other reflective channel having a second wall which reflects the received light and transmits the light to a light dump, said method comprising: 
 irradiating said first wall with light of a wavelength range of interest at an angle which results in reflection of a beam orthogonal to said channels, whereby said light is transmitted through said channels.    
     
     
         12 . A method according to  claim 11 , wherein the number of channels is in the range of 1-5.  
     
     
         13 . A method according to  claim 11 , wherein said irradiating is with an argon light source.  
     
     
         14 . A method according to  claim 11 , wherein said solid substrate is glass or plastic.  
     
     
         15 . A method according to  claim 14 , wherein said plastic is poly(methyl methacrylate.)