ABSTRACT
Several strategies have been developed to immobilize oligonucleotides on insoluble supports. In principle, three different approaches have been investigated: covalent linkage of the oligonucleotides via their terminals using one-step or multistep reaction and immobilization through a secondary valence. A more versatile, multistep procedure has been reported which is applicable to polynucleotides of both synthetic and natural origin and has the added practical advantage that polymers may also be incorporated onto cellulose paper strips as well as cellulose powder. In system the terminal phosphate group or polyphosphate group of a polynucleotide is activated in aqueous solution under mild conditions with a water-soluble reagent, and although the mechanism of the reaction differs from that operating in anhydrous synthesis, product obtained is thought to be similar, as it consists of cellulose containing covalently bound polynucleotide chains each of which is connected to the cellulose at its 3' or 5' terminal by a phosphodiester linkage or a linkage involving a diester of polyphosphoric acid.
