A G-Quadruplex Hydrogel via Multicomponent Self-Assembly: Formation and Zero-Order Controlled Release.

Stimuli-sensitive hydrogels are ideal candidates for biomedical and bioengineering purposes, although applications of hydrogels may be limited, due in part to the limited choice of suitable materials for constructing hydrogels, the complexity in the synthesis of the source materials, and the undesired fast-then-slow drug-release behaviors of usual hydrogels. Herein, we describe the fabrication of a new supramolecular guanosine (G)-quadruplex hydrogel by multicomponent self-assembly of endogenous guanosine (G), 2-formylboronic acid (2-FPBA), and tris(2-aminoethyl)amine (TAEA) in the presence of KCl in an easy and convenient way. The features of the G-quadruplex hydrogel include (1) versatility and commercial availability of building blocks with different functions, (2) dynamic iminoboronate bonds with pH and glucose responsiveness, and (3) zero-order drug-release behavior because of the superficial peel-off of the hydrogel in response to stimuli. The structure, morphology, and properties of the G-quadruplex hydrogel were well-characterized, and satisfactory zero-order drug release was successfully achieved. This kind of supramolecular G-quadruplex hydrogels may find applications in biological fields.