Tannic acid coating modification of polypropylene providing pH-responsive antibacterial and anti-inflammatory properties applicable to ostomy patches.

We report highly efficient, antioxidant, anti-inflammatory, pH-responsive antibacterial coatings developed via direct assembly of a nature compound tannic acid (TA) with the cationic antibiotic quaternized polyethyleneimine (QPEI). The surface of polypropylene was modified with these coatings. Under acidic conditions, the coatings significantly enhanced the antibacterial performance against Staphylococcus aureus and Escherichia coli, and the antibacterial rate reached more than 90 %. The free radical scavenging rate could exceed 91 %. Thus, the excess reactive oxygen species (ROS) could be cleared, and the oxidative stress production could be significantly reduced. In vitro anti-inflammatory experiments revealed that the coatings significantly reduced the expression of TNF-α and IL-6 and promoted the release of IL-10. These results indicated the excellent anti-inflammatory effects of the coatings. In vivo experiments revealed that the coatings could rapidly achieve bactericidal effects and subsequently prevent inflammatory reactions, thereby inhibiting the generation of fibrosis. Through molecular docking simulation experiments, the mechanism of LBL self-assembly between QPEI and TA components has been clarified for the first time. By designing the surface coating of a material and combining it with bioactive components, multiple functions could be achieved to meet the clinical needs of stoma patches and promote the development of medical materials.