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. In other embodiments, unlabeled nucleic acids are used. Exonuclease treatment of the nucleic acid results in the release of labeled or unlabeled nucleotides that are detected by Raman spectroscopy. In alternative embodiments of the invention, nucleotides released from a nucleic acid by exonuclease treatment are covalently cross-linked to nanoparticles and detected by surface enhanced Raman spectroscopy (SERS), surface enhanced resonance Raman spectroscopy (SERRS) and/or coherent anti-Stokes Raman spectroscopy (CARS). Other embodiments of the invention concern apparatus for nucleic acid sequencing.

1 - 26 . (canceled)  
   
   
       27 . An apparatus comprising: 
 a) a reaction chamber;    b) a microfluidic channel in fluid communication with the reaction chamber;    c) a flow-through cell in fluid communication with the microfluidic channel; and    d) a Raman detection unit operably coupled to the flow-through cell.    
   
   
       28 . The apparatus of  claim 27 , wherein the Raman detector is capable of detecting single molecules of nucleotides.  
   
   
       29 . The apparatus of  claim 28 , wherein the nucleotides are unlabeled.  
   
   
       30 . The apparatus of  claim 27 , further comprising nanoparticles in the flow-through cell.