A natural polymer based bioadhesive with self-healing behavior and improved antibacterial properties

Bioadhesives are of great interest for tissue/wound closure to reduce surgical time, minimize treatment invasiveness, and prevent body fluid leakage. However, bacterial infections remain a major concern during wound healing and tissue bonding. Hence, the development of bioadhesives with antibacterial properties is necessary. In this study, a hydrogel bioadhesive based on silk fibroin (SF) and tannic acid (TA) was combined with silver nanoparticles (AgNPs) generated in situ during hydrogel formation to improve its antibacterial abilities. In this system, TA can be regarded as a phenolic glue molecule to spontaneously co-assemble with SF to fabricate the adhesive matrix network and also as a reductant to induce silver nitrate to form AgNPs evenly within the adhesive network. Furthermore, the influence of the amount of silver nitrate was considered. The produced hybrid hydrogel bioadhesives with different amounts of AgNPs exhibited self-healing capabilities, considerable wet tissue adhesion strengths (14.32 ± 1.85 kPa-28.80 ± 2.29 kPa) and good cytocompatibility. When the initial concentration of silver nitrate was more than 0.05 wt%, the produced STA bioadhesive showed effective antibacterial properties in vitro. These results demonstrate that these STA bioadhesives have the potential to be used in tissue/wound closure, especially when bacterial infections are a main problem.