Chitosan coated bacteria responsive metal-polyphenol coating as efficient platform for wound healing

The extensive use of antibiotics causes drug resistance, which slows the healing process in wound infections and this calls for an urgent response to the development of novel therapeutic approaches. However, it is challenging to develop materials with intrinsic and effective antibacterial properties for enhanced wound healing. Here, a highly efficient, bacteria-responsive and controlled-release silver ion coating was constructed by the assembly of quaternized chitosan (QCS), tannic acid (TA), and silver ions using the layer-by-layer method. The coating platform exhibited a distinct "self-defense" behavior triggered by acidification and good antibacterial activity against both gram-negative and gram-positive bacteria, which was further enhanced by the positively charged groups of QCS and the release of silver ions. Moreover, the coatings exhibited excellent biocompatibility, highlighted by promoting both fibroblast and endothelial cell proliferation, supporting fibroblast migration, suppressing macrophage activation, and modulating inflammatory cytokine release. Notably, animal experimental results further revealed that the coatings terminated bleeding, inhibited bacterial growth and accelerated healing at the wound site. Collectively, the coatings showed outstanding hemostatic performance and antimicrobial activity as well as improved wound healing process, which might be as a promising wound treatment platform.