Engineering nanocomposite hydrogels using dynamic bonds

Nanocomposite (NC) hydrogels are promising biomaterials that possess versatile properties and functions for biomedical applications such as drug delivery, biosensor development, imaging and tissue engineering. Different strategies and chemistries have been utilized to define the structure and properties of NC hydro gels. In this review, we discuss NC hydrogels synthesized using dynamic bonds, including dynamic covalent bonds (e.g., Schiff base and boronate ester bond) and non-covalent bonds (e.g., hydrogen bonds and metal-ligand coordination). Dynamic bonds can reversibly break and reform to provide self-healing properties to NC hydrogels as well as be influenced by external factors to allow NC hydrogels with stimulus responsiveness. The presence of dynamic bonds in NC hydrogels can occur at the polymer-polymer or polymer-particle interfaces, which also determines whether the particles act as fillers or crosslinkers in hydrogels. Several representative examples of NC hydrogels fabricated using dynamic bonds are discussed here, focusing on their design, preparation, properties, applications and future prospects.

Automated summary

Nanocomposite hydrogels synthesized using dynamic bonds, including both dynamic covalent and non-covalent bonds, offer versatile properties for biomedical applications. Dynamic bonds provide self-healing and stimulus responsiveness to the hydrogels, and their presence at polymer interfaces determines the role of particles as fillers or crosslinkers in the hydrogels. Multiple examples of NC hydrogels fabricated using dynamic bonds are discussed in this review, highlighting their design, preparation, properties, applications, and future prospects.