A Hydrophilic/Hydrophobic Janus Membrane Used as Wound Dressings with Enhanced Antibacterial Properties

In this study, an asymmetric wettable composite wound dressing consists of hydrophobic polyvinylidene fluoride (PVDF) outer layer and a hydrophilic polydopamine (PDA) coated Ag nanoparticles (Ag NPs)/PVDF layer (PVDF-Ag-PDA) was successfully prepared through electrospinning and PDA coating. The results show that the contact angle of the PVDF surface is 132.8°, while the PDA-coated surface is nearly 0°, indicating an asymmetric wettability. The highly hydrophilic PVDF-Ag-PDA layer can significantly reduce bacterial growth, while the PVDF layer with a small pore size and high hydrophobicity can prevent bacterial adherence. In addition, cytotoxic assays showed that PVDF/PVDF-Ag-PDA present a high cell viability percentage (above 80 %), which is attributed to that the thin layer of PDA can alleviate the cytotoxicity of Ag NPs. Therefore, the Janus wound dressing noted as PVDF/PVDF-Ag-PDA has the potential for practical applications with the advantages mentioned above.