Photo-Switching from Enzymatic Reaction to DNA Self-Assembly Enabled by a Caged Cationic Copolymer.

Enzymatic reactions that act on DNA and DNA self-assembly reactions have been harnessed to create sophisticated dynamic DNA nanodevices. Methods for temporally and spatially controlling these reactions will enable creation of more advanced DNA nanodevices. We previously reported that cationic graft copolymers activate DNA self-assembly reactions including DNA hybridization and strand displacement reactions while inhibiting reactions catalyzed by enzymes that act on DNA. In this study, we prepared a photoactivatable graft copolymer as a tool to spatiotemporally switch between enzymatic and self-assembly reactions upon photoirradiation. The graft copolymer caged at their amino groups with photocleavable 6-nitroveratryloxycarbonyl moieties did not inhibit polymerase reactions and did not activate toehold-mediated strand displacement reactions. After UV irradiation to uncage the amino groups of the copolymer, polymerase activity was inhibited and toehold-mediated strand displacement was activated. Thus, remote switching from polymerization to toehold-mediated strand displacement was performed by photoirradiation.