Leveraging Dynamic Electrostatic and Hydrophobic Interactions for Biomedical Hydrogels.

The reversibility of dynamic cross-links affords hydrogel-enhanced responsiveness to external stimuli, making them useful in a variety of biomedical applications. While numerous types of dynamic interactions exist, electrostatic and hydrophobic interactions are notably potent. Herein, recent reports are highlighted that demonstrate the utility of these interactions to form hydrogels with notable properties such as stimuli-responsiveness, adhesivity, injectability, self-healing, and toughness. While most often utilized independently, emerging reports show that hydrogels can be formed with a synergistic combination of electrostatic and hydrophobic interactions. The applications of such dynamic hydrogels are broad but include drug delivery, wound healing, cartilage regeneration, and sensing. The highlighted reports underscore the diversity of approaches that can be employed to impart and tailor electrostatic and hydrophobic interactions to hydrogels, including polymer chemistry and architecture, as well as network design that may also include covalent cross-linking.