Methods to increase nucleotide signals by Raman scattering

Abstract

The methods and apparatus disclosed herein concern nucleic acid sequencing by enhanced Raman spectroscopy. In certain embodiments of the invention, nucleotides are covalently attached to Raman labels before incorporation into a nucleic acid 13 . Exonuclease 15 treatment of the labeled nucleic acid 13 results in the release of labeled nucleotides 16, 130, which are detected by Raman spectroscopy. In alternative embodiments of the invention, nucleotides 16, 130 released from a nucleic acid 13 by exonuclease 15 treatment are covalently cross-linked to silver or gold nanoparticles 140 and detected by surface enhanced Raman spectroscopy (SERS), surface enhanced resonance Raman spectroscopy (SERFS) and/or coherent anti-Stokes Raman spectroscopy (CARS). Other embodiments of the invention concern apparatus 10, 100, 210 for nucleic acid sequencing.

1 - 23 . (canceled)  
   
   
       24 . An apparatus comprising: 
 a) a reaction chamber;    b) a first channel in fluid communication with said reaction chamber;    c) a second channel in fluid communication with said first channel;    d) a flow-through cell in fluid communication with said first and second channels; and    e) a detection unit operably coupled to said flow-through cell.    
   
   
       25 . The apparatus of  claim 24 , wherein said detection unit comprises a Raman detector.  
   
   
       26 . The apparatus of  claim 25 , wherein said detection unit comprises a laser and a CCD camera.  
   
   
       27 . The apparatus of  claim 24 , said first channel to contain nucleotides and said second channel to contain nanoparticles.  
   
   
       28 . The apparatus of  claim 27 , wherein said nucleotides are covalently attached to said nanoparticles.  
   
   
       29 . The apparatus of  claim 28 , wherein said nucleotides become covalently attached to said nanoparticles within said channels.  
   
   
       30 . The apparatus of  claim 28 , wherein covalent attachment of said nucleotides to said nanoparticles provides an enhanced Raman signal.