Pullulan-based nanocomposite films with enhanced hydrophobicity and antibacterial performances

Pullulan is a linear homopolysaccharide of glucose and produced by certain strains of the polymorphic fungus Aureobasidium pullulans. It has long been widely used in various fields from food additives to environmental remediation agents. In this study, a new composite films material pullulan/tributyl citrate (TBC)/copper-containing metal–organic frameworks (Cu-MOFs) were prepared. Through Fourier-transform infrared spectroscopy (FTIR), X-ray diffraction (XRD), scanning electron microscope (SEM), and energy-dispersive X-ray spectroscopy (EDS), the existence of different components in the composite film was verified. Further studies confirmed that the content of the hydrophobic plasticizer TBC component improves the ultraviolet (UV) absorption efficiency of the composite material, but has little effect on the visible light region. At the same time, with the increase of TBC content, the water resistance of the composite material has been significantly promoted from seconds to minutes without being damaged. The antibacterial activity and biocompatibility of the composite material were also evaluated. The results showed that the presence of Cu-MOFs enables composite material to possess good antibacterial properties and the antibacterial rates against Escherichia coli ( E. coli ) and Staphylococcus aureus ( S. aureus ) were high to 99.9%. Besides, the composite material maintained the excellent biocompatibility of pullulan polymer and the cell survival rates of the samples were more than 100%, indicating that the pullulan/TBC/Cu-MOFs composite film can enhance cell proliferation. Therefore, the composite materials can effectively overcome the shortcomings of pure pullulan polymer films, such as poor water resistance and lack of antibacterial properties, and expand the application prospects of pullulan polymers.