Method for immobilizing nucleic ligands

A process for immobilizing nucleic ligands on a solid support for chromatography, comprising the following steps:

• a) providing a solid support comprising a surface, wherein the solid support is selected from the group consisting of silica gels, polysaccharide gels, acrylamide gels, methacrylate gels, and polystyrene surfaces, and
• wherein the surface of the solid support comprises activated carboxylic acid groups in the form of N-hydroxysuccinimidyl ester groups of the following formula:
• wherein R is the solid support,
• b) providing a nucleic ligand of formula (I):
• NH2-[SPAC]n-[NUCL] (I)
• wherein:
• n is 1 or 0,
• [SPAC] is a spacer chain, and
• [NUCL] is a nucleic acid aptamer moiety which binds specifically to a target protein,
• said nucleic acid aptamer moiety having a length of 5 to 120 nucleotides,
• c) covalently coupling said nucleic ligand on the solid support by reacting the NH2 of formula (I) with the activated carboxylic acid groups of the solid support at a pH ranging from 3.5 to 4.5, to immobilize the nucleic ligand on the solid support by an amide bond,
• wherein steps a) and b) may be in any order preceding step c), and
• wherein the resulting solid support is provided in a chromatography column suitable for protein purification.