Rigidity-dependent formation process of DNA supramolecular hydrogels

A DNA building block with tunable rigidity was constructed, and the corresponding hydrogel formation process was investigated accordingly. A high rigidity was demonstrated to facilitate fast gelation. Different gelation pathways of the rigid and flexible building blocks were revealed, and a cyclized dimer intermediate was proposed. The energy barrier of the ring-opening process was also shown to play a fundamental role in determining the gelation kinetics. Furthermore, the hydrogel molecular network rigidity was also tuned in situ through strand displacement, which also supports the kinetic control mechanism of the formation process of DNA hydrogels.