Fig. 1
Design strategy for the plant-inspired catechol-chemistry-based self-adhesive, tough, and antibacterial NPs-P-PAA hydrogel. a Generation of radicals by the redox reaction between Ag-Lignin NPs and ammonium persulfate (APS), triggering the gelation of the hydrogel under an ambient environment. b Quinone-catechol reversible reaction maintains dynamic balance. c Scheme of molecular structure of plant-inspired adhesive and tough hydrogel. d Electron spin-resonance spectroscopy (ESR) spectra for quinone radical detection. e Transmission electron microscope (TEM) micrograph shows the core-shell structure of Ag-Lignin NPs; the inset is Ag element mapping. f High-resolution transmission electron microscopy (HRTEM) micrograph shows the structure of Ag-Lignin NPs; the inset is high-resolution lattice. g Scanning electron microscope (SEM) micrograph shows the microfibril structures in the hydrogel; the inset presents typical microfibrils. NPs, nanoparticles; P, pectin; PAA, polyacrylic acid
