Hydrogel formation via hybridization of oligonucleotides derivatized in water-soluble vinyl polymers

Succinimido-copolymers, poly(N,N-dimethylacrylamide-co-N-acryloyloxysuccinimide)s, were coupled with 5′-terminal-amino-modified oligodeoxyribonucleotides (ODNs) to produce water-soluble copolymers partially derivatized with ODNs in their side chains. The mixing and thermal melting measurements of dilute mixed aqueous solutions of an ODN-derivatized copolymer and their complementary ODN and mixed solutions of complementary ODN-derivatized copolymers were monitored by ultraviolet spectroscopy. The results showed that hybrids were formed with their complementary ODNs at room temperature, but dissociated at high temperature. Based on the hybridization between complementary base pairs of nucleic acids and its thermal dissociation characteristics, two types of thermoresponsive hydrogels were prepared: (1) a hydrogel formed via hybridization between an oligodeoxythymidylate (oligoT)-derivatized copolymer and an oligodeoxyadenylate (oligoA), and (2) a hydrogel formed by hybridization between complementary oligoT- and oligoA-derivatized copolymers. Thus, selfassociation due to specific intermolecular hydrogen bonding between nucleic acid base pairs enabled the preparation of a novel thermoresponsive hydrogel.