Methods and compositions for aptamers against anthrax

Abstract

The present invention concerns methods of preparing nucleic acid ligands against anthrax spores, compositions comprising anthrax specific nucleic acid ligands and methods of use of such ligands for detection and/or neutralization of anthrax spores.

What is claimed is:  
     
         1 . Amethod for preparing one or more nucleic acid ligands against  Bacillus anthracis  (anthrax) spores comprising: 
 a) obtaining anthrax spores;    b) obtaining a pool of nucleic acid ligands;    c) contacting said spores with said pool under conditions allowing binding of one or more nucleic acid ligands to the anthrax spores;    d) separating ligands bound to the spores from ligands that do not bind to the spores; and    e) collecting one or more anthrax binding nucleic acid ligands.    
     
     
         2 . The method of  claim 1 , further comprising repeating (c) through (e) until one or more anthrax binding nucleic acid ligands of a desired degree of specificity or binding affinity against anthrax spores is obtained.  
     
     
         3 . The method of  claim 2 , wherein the nucleic acid ligand binds to anthrax spores with high affinity.  
     
     
         4 . The method of  claim 2 , wherein the nucleic acid ligand is highly specific for anthrax spores.  
     
     
         5 . The method of  claim 4 , wherein the nucleic acid ligand binds only to anthrax spores.  
     
     
         6 . The method of  claim 1 , wherein the pool of nucleic acid ligands are attached to magnetic beads.  
     
     
         7 . The method of  claim 1 , wherein the nucleic acid ligands are operably linked to an organic semiconductor.  
     
     
         8 . The method of  claim 7 , wherein the organic semiconductor is diazoluminomelanin (DALM).  
     
     
         9 . The method of  claim 7 , wherein the organic semiconductor is a polyphenylene.  
     
     
         10 . The method of  claim 1 , wherein said separating comprises nitrocellulose filtration.  
     
     
         11 . The method of  claim 10 , wherein nucleic acid ligands that bind to nitrocellulose filters in the absence of anthrax spores are removed from the pool of nucleic acid ligands before contacting the anthrax spores with the pool.  
     
     
         12 . The method of  claim 1  or  claim 2 , wherein the nucleic acid ligands comprise 40-mers of random sequence, the random 40-mers attached at their 5′ and 3′ ends to primer binding sequences.  
     
     
         13 . The method of  claim 12 , further comprising amplifying the nucleic acid ligands using a 5′ primer and a 3′ primer.  
     
     
         14 . The method of  claim 12 , wherein biotin residues are attached to the 5′ ends of the 5′ primer binding sequences.  
     
     
         15 . The method of  claim 13 , wherein biotin residues are attached to the 5′ ends of the 5′ primers.  
     
     
         16 . The method of  claim 15 , wherein ssDNA to be used for SELEX screening is prepared by binding of biotin-labeled nucleic acid ligands to streptavidin conjugated beads.  
     
     
         17 . The method of  claim 15 , wherein anthrax binding nucleic acid ligands are collected by binding to streptavidin conjugated beads.