Fig. 13.

(A) Injectability and printability properties of the G–NapBA/K⁺ hydrogel (vitamin B₁₂-loaded gel was extruded through a 24 ​G syringe). (B) Demonstration of the self-healing ability of the G-quadruplex hydrogel. (C) Optical images of the self-healing process. Sequence of self-healing observed by the methyl red dye-doped hydrogel, and a hang test confirms the healed gel. (D) Schematic representation of the self-healing process in the presence of dynamic reversible boronate esters. (E) Self-healing mechanism. (F) Graphical representation of the formation of G-quadruplex, leading to the formation of a self-supporting hydrogel (G/1-NapBA/KOH ​= ​50:25:25 ​mM). Reproduced with permission [80]. Copyright 2020, American Chemical Society. (For interpretation of the references to color in this figure legend, the reader is referred to the Web version of this article.)