Dynamic, Bioresponsive Hydrogels via Changes in DNA Aptamer Conformation.

DNA aptamers are integrated into synthetic hydrogel networks with the aim of creating hydrogels that undergo volume changes when exposed to target molecules. Specifically, single-stranded DNA aptamers in cDNA-bound, extended state are incorporated into hydrogel networks as cross-links, so that the nanoscale conformational change of DNA aptamers upon binding to target molecules will induce macroscopic volume decreases of hydrogels. Hydrogels incorporating adenosine triphosphate (ATP)-binding aptamers undergo controllable volume decreases of up to 40.3 ± 4.6% when exposed to ATP, depending on the concentration of DNA aptamers incorporated in the hydrogel network, temperature, and target molecule concentration. Importantly, this approach can be generalized to aptamer sequences with distinct binding targets, as demonstrated here that hydrogels incorporating an insulin-binding aptamer undergo volume changes in response to soluble insulin. This work provides an example of bioinspired hydrogels that undergo macroscopic volume changes that stem from conformational shifts in resident DNA-based cross-links.