Tannic acid/polyvinyl alcohol/2-hydroxypropyl trimethyl ammonium chloride chitosan double-network hydrogel with adhesive, antibacterial and biocompatible properties

Hydrogels have great potential for biomedical applications. However, there are still significant challenges in preparing biomass-based hydrogels with excellent adhesive, antibacterial and biocompatible properties. In this study, pure physically cross-linked tannic acid (TA)/polyvinyl alcohol (PVA)/2-hydroxypropyltrimethyl ammonium chloride chitosan (HACC) double-network (PVA/HACC-TA) hydrogels are prepared by a combination approach of cyclic freeze-thaw and soaking method. The prepared PVA/HACC-TA hydrogels are formed by hydrogen bond cross-linking and do not use any toxic and harmful cross-linking agents. Meanwhile, the prepared PVA/HACC-TA hydrogels have excellent mechanical properties, the maximum tensile strength can reach 4.13 MPa and the maximum tensile strain can attain 830%. In addition, PVA/HACC-TA hydrogels display good adhesion to different materials. At the same time, the PVA/HACC-TA hydrogels also show favorable antibacterial activities. Therefore, the excellent mechanical, adhesive, antibacterial and cytocompatible biomass hydrogels showed promising potential applications in the biomedicine field, especially as the skin wound dressings. (a-b) Illustration of the fabrication of PVA/HACC-TA hydrogels and their possible formation mechanism. (c-h) The hydrogen bonds between HACC and HACC, TA and TA, PVA and PVA, HACC and PVA, TA and PVA, as well as PVA and HACC, respectively. • The two-step method produces an excellent performance of hydrogels. • The hydrogels were prepared without using any chemical cross-linking agents. • The mechanical properties of hydrogels are significantly improved. • PVA/HACC-TA hydrogels have excellent adhesion. • Hydrogels have good antibacterial properties and bio-compatibility.