Fabrication of eco-friendly and efficient flame retardant modified cellulose with antibacterial property.

Flame retardant and antibacterial investigation of cellulose has attracted more and more attention. In order to improve the modification efficiency, inspired by multiple hydrogen bonding in spider silk, flame retardant and antibacterial dual function modified cellulose was achieved by multi structure hydrogen bonding in this research. A novel nano SiO2 based Schiff base flame retardant (SiAPH) and dodecyl quaternary ammonium salt (HDAC) were synthesized. Tannin (TA) was introduced as medium to provide synergistic flame retardant and antibacterial with SiAPH and HDAC. The flame retardancy assessment demonstrated that the limiting oxygen index (LOI) of modified cotton fabrics increased from 18% to 26.1%, and the peak of heat release rate (pHRR) decreased by 41.0%, UL-94 vertical combustion proved the modified cotton fabrics had capability of self-extinguishing. The antibacterial of modified fabrics were confirmed against Staphylococcus aureus and Escherichia coli, and the inhibition rate reached to 99.1%. In addition, it worth noting that the biocompatibility and antibacterial activity of modified fabrics were evaluated via MTS assay and establishment of animal wound model. Low toxicity of the fabrics was verified by the L929 fibroblast cells. The anti-infection experiment model showed that the modified fabrics had a positive effect on prevention of infection, and the wound healing rate reached to 86.8% after 14 days' treatment. The flame retardancy, antibacterial and biocompatibility of the functional cotton fabrics indicated that they were ideal candidate for applications of vehicle interior, soft decoration in public and medical scene.

Water-stable zirconium-based metal-organic frameworks armed polyvinyl alcohol nanofibrous membrane with enhanced antibacterial therapy for wound healing.

Inadequate water-stability and antibacterial activity limit the biomedical application of polyvinyl alcohol (PVA)-based membranes in moist environments. In this work, we propose a strategy to improve the water-stability of PVA membranes via metal complexation and heat treatment. We report a simple routine where the zirconium-based UiO-66-NH2 metal-organic frameworks (MOFs) are nucleated as a layer on the surface of PVA nanofibrous membranes (UiO-66-NH2@PVA NFMs). We find that the chemical modification of membranes increases their hydrophilicity and adds on mechanical support for the brittle UiO-66-NH2 MOFs. Additionally, we demonstrate the application of UiO-66-NH2 MOFs as drug carriers for antibacterial drug, levofloxacin (LV). The active drug component is preloaded during the one-step nucleation process. The obtained LV loaded UiO-66-NH2@PVA NFMs (LV@UiO-66-NH2@PVA) are shown to be bactericidal with the efficiency > 99.9% at 100 µg/mL against two bacterial species, Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus). Compared with the commercially available gauzes, the UiO-66-NH2@PVA and LV@UiO-66-NH2@PVA treatments will significantly improve the wound healing process. Animal studies show that the LV@UiO-66-NH2@PVA will effectively offer a safe alternative solution for the patients to protect against bacterial infections, demonstrating the potential application of MOF-based NFMs as wound dressing agents.