A pH-Triggered, Fast-Responding DNA Hydrogel

摘要

Over the past two decades, DNA has been demonstrated as an excellent building material for nanotechnology, especially in the fabrication of novel functional DNA nanostructures and nanomotors. In addition to planar two-dimensional grids and isolated three-dimensional nanostructures, the concept of DNA assembly has recently been expanded to realize unconstrained three-dimensional DNA structures, such as "DNA dendrimers" and "DNA hydrogels". The reported gelling processes, which are based on double-helix formation followed by enzyme-catalyzed ligation, are rather slow and require overnight ligation at room temperature. Furthermore, the release of the entrapped materials and drugs from the gel is very slow; for example, it takes over 10 days to release entrapped insulin. This may limit the potential applications of these gels if fast trapping and releasing processes are required. In this study, we report the preparation of a fast, pH-responsive DNA hydrogel with three-armed DNA nanostructures (Y units) assembled together through the formation of intermolecular i-motif structures. This DNA hydrogel can be switched to the non-gel state in one minute by simply using environmental pH changes.