Stretchable, adhesive and antibacterial mussel-inspired cellulose nanocrystal/pectin biomass-based multifunctional tough hydrogels

The multifunctional biocompatible hydrogels have attracted widespread attention in biomedical applications such as the fields of biomimetic tissues, wound dressings and biosensors. But it is a great challenge to facilely develop a hydrogel with favorable mechanical strength, adhesion performance, anti-swelling behavior, antibacterial activity and biocompatibility at the same time. Inspired by the mechanical reinforcement mechanism of double network and nanocomposite hydrogels as well as the adhesion mechanism of mussel, tannic acid-coated cellulose nanocrystals (TA@CNC)/pectin/polyacrylic acid nanocomposite hydrogels (TPP hydrogels) are reported in this work. The obtained TPP hydrogels exhibited high stretchability with the fracture strain of more than 1400%, and excellent elasticity and fatigue resistance. Additionally, the abundant catechol groups on TA@CNC nanoparticles endow TPP hydrogels with good adhesiveness and can adhere to various hydrophilic and hydrophobic substrates such as wood, glass, polytetrafluoroethylene and biological tissues. Moreover, TPP hydrogels also exhibited the significant anti-swelling properties expressed that the equilibrium swelling ratio of the tested TPP hydrogel was only 19.25% as much as that of the polyacrylic acid hydrogel. In addition, TPP hydrogels displayed favorable antibacterial properties against Escherichia coli and Staphylococcus aureus, and can effectively support the adhesion, growth and proliferation of mouse fibroblasts for showing cytocompatibility. All the results imply that TPP hydrogels have promising potential in biomedical application.