Intelligent, Biodegradable, and Self‐Healing Hydrogels Utilizing DNA Quadruplexes

A new class of hydrogels utilizing DNA (DNA quadruplex gel) has been constructed by directly and symmetrically coupling deoxynucleotide phosphoramidite monomers to the ends of polyethylene glycols (PEGs) in liquid phase, and using the resulting DNA‐PEG‐DNA triblock copolymers as macromonomers. Elongation of merely four deoxyguanosine residues on PEG, which produces typically ≈10 grams of desired DNA‐PEG conjugates in one synthesis, resulted in intelligent and biodegradable hydrogels utilizing DNA quadruplex formation, which are responsive to various input signals such as Na(+), K(+), and complementary DNA strand. Gelation of DNA quadruplex gels takes place within a few seconds upon the addition of a trigger, enabling free formation just like Ca(+)‐alginate hydrogels or possible application as an injectable polymer (IP) gel. The obtained hydrogels show good thermal stability and rheological properties, and even display self‐healing ability.