Materials and methods for the purification of polyelectrolytes, particularly nucleic acids

Abstract

This invention describes materials and methods usable for the purification of polyelectrolytes, such as nucleic acids and proteins. The materials of the invention are separation media that possess pH-dependent groups with pKa value in the range of about 5 to about 7. Separation of the nucleic acids or proteins from a separation medium is effected at a neutral or higher pH.

I claim:  
     
         1 . A polymeric separation medium for recovery of a polyelectrolyte from a liquid, which separation medium contains pendant, pH-dependent groups exhibiting a pKa value in the range of about 5 to about 7.  
     
     
         2 . The separation medium of  claim 1  wherein the pH-dependant groups are basic groups.  
     
     
         3 . The separation medium of  claim 2  wherein the pendant basic groups are derived from a base which is a member of the group consisting of pyridine, quinoline, imidazole, and pyrimidine.  
     
     
         4 . The separation medium of  claim 1  wherein the pendant groups are acid groups.  
     
     
         5 . The separation medium of  claim 4  wherein the pendant acidic groups are a member of the group consisting of a carboxylic group and a phenolic group.  
     
     
         6 . The separation medium of  claim 1  wherein the polymer is a polysaccharide.  
     
     
         7 . The separation medium of  claim 6  wherein the polysaccharide is a member of the group consisting of agarose, dextran, and cyclodextrin.  
     
     
         8 . The separation medium of  claim 1  wherein the separation medium is a water-insoluble substrate.  
     
     
         9 . The separation medium of  claim 8  wherein the substrate includes magnetizable particles.  
     
     
         10 . A composition suitable for recovery of a polyelectrolyte from a liquid by convective flow, which composition includes: 
 (a) a liquid permeable porous support;    (b) a porous separation medium contained within the pores of the porous support, said medium having pendant, pH-dependent groups exhibiting a pKa value in the range of about 5 to about 7.    
     
     
         11 . The composition of  claim 10  wherein an inert casing encloses the composition, which casing includes an inlet and outlet ports.  
     
     
         12 . The composition of  claim 10  wherein the pH-dependent groups are organic bases.  
     
     
         13 . The composition of  claim 12  wherein the bases are selected from the group consisting of pyridine quinoline, imidazole, and pyrimidine.  
     
     
         14 . The separation medium of  claim 10  wherein the pendant groups are organic acid groups.  
     
     
         15 . The separation medium of  claim 14  wherein the acids are members of the group consisting of a carboxylic group and a phenolic group.  
     
     
         16 . The composition of  claim 10  wherein the polymeric separation medium is a polysaccharide.  
     
     
         17 . The composition of  claim 13  wherein the polysaccharide is a member of the group consisting of agarose, dextran, and a cyclodextrin.