Originally, we could make DNA hydrogel composed of X motif[1]. X motif means the mesh structure consisted of 4 kinds of strand that hybridize each other.
Previous research revealed loop structure can be opened by its complementary strand and this could make DNA -organic polymer hybrids swell[2].
Our goal of this experiment was to make f pure DNA hydrogels swell and shrink, so the linker loops were added in X motif.
Then, in our hypothesis, those linker loops would open when the complementary strands were added to the hydrogels, and the size of the mesh would expand, and consequently the size of the gels would grow. Moreover, if strands complementary to the added strands were added after the gel swelled, both added strands would form double-stranded DNA together, which would be more stable. Then, the loop structure of the gels would be recovered, and consequently the size of the gels would be smaller.
Reference
[1] Kandatsu, D., Cervantes-Salguero, K., Kawamata, I., Hamada, S., Nomura, S. ichiro M., Fujimoto, K., & Murata, S. (2016). Reversible Gel–Sol Transition of a Photo-Responsive DNA Gel. ChemBioChem, 1292, 1118–1121. https://doi.org/10.1002/cbic.201600088
[2] Murakami, Y., & Maeda, M. (2005). DNA-responsive hydrogels that can shrink or swell. Biomacromolecules, 6(6), 2927–2929. https://doi.org/10.1021/bm0504330