Ascidian-Inspired Supramolecular Cellulose Nanocomposite Hydrogels with Antibacterial Activity

The design of ultratough hydrogels has recently emerged as a topic of great interest in the scientific community due to their ability to mimic the features of biological tissues. An outstanding strategy for preparing these materials relies on reversible and dynamic cross-links within the hydrogel matrix. In this work, inspired by the composition of ascidians' tunic, stretchable supramolecular hydrogels combining poly(vinyl alcohol), green tea-derived gallic acid, and rigid tannic acid-coated cellulose nanocrystals (TA@CNC) were designed. The addition of TA@CNC nanofillers in concentrations up to 1.2 wt % significantly impacted the mechanical and viscoelastic properties of the hydrogels due to the promotion of hydrogen bonding with the polymer matrix and polyphenols π-π stacking interactions. These supramolecular associations endow the hydrogels with excellent stretchability and strength (>340%, 540 kPa), low thermoreversible gel-sol transition (60 °C), and remolding ability, while the natural polyphenols provided potential antibacterial properties. These versatile materials can be anticipated to open up new prospects for the rational design of polyphenol-based cellulosic hydrogels for different biomedical applications.