Instant hydrogel formation of terpyridine-based complexes triggered by DNA via non-covalent interaction

Abstract

Biomolecule-based hydrogels have potential use in a wide range of applications such as controlled drug release, tissue engineering, and biofabrication. Herein, driven by specific interactions between ds-DNA (double-stranded DNA) and Zn²⁺ based metal-complexes, we report that the use of DNA as cross-linkers can enhance interactions between self-assembling Zn²⁺ complexes containing terpyridine and sugar groups in the generation of bioinspired hydrogels from solutions or suspensions. The gelation process is fast and straightforward without tedious steps and happens at room temperature. Such a hydrogelation process of different Zn²⁺ complexes endows the visualized and selective DNA analogue discrimination. Several experiments suggest that the strong intercalation binding of Zn²⁺ complexes with ds-DNA results in the unzipping of ds-DNA into ss-DNA (single-stranded DNA), which further behave as linkers to enhance the intermolecular interactions of self-assembling Zn²⁺ complex molecules via coordination interactions. This work demonstrates an efficient and universal strategy to prepare hydrogels based on biomolecular recognition. Moreover, the DNA responsive behaviors of Zn²⁺ complexes are further compared with that of solutions and cells.