A versatile Silk Fibroin based filtration membrane with enhanced mechanical property, disinfection and biodegradability

Traditional fibrous materials are used for air filtration, but show limited filtration efficiency, poor biocompatibility, non-degradability, and non-disinfection features. Meanwhile, filter materials based on non-woven fabrics seriously increase the burden on the environment. Silk Fibroin (SF), a natural polymer with high levels of biocompatibility, degradability, and environmental sustainability, is a highly promising material from air filtration perspectives. However, it is still a challenge to improve the mechanical strength of SF based membranes, high filtration efficiency and remarkable disinfection. Here, we develop an alternative strategy for facile fabrication of a flexible and multifunctional SF based membrane composed of SF nanofibers doped with piezoelectric LiNbO₃ (LN) nanoparticles and graphitic carbon nitride (g-C₃N₄) via the electrospinning method. The LN enhances the mechanical properties of the SF based membrane and endows it with piezoelectric properties for generating electrostatic interaction, which can improve the absorption of particulate matters (PMs) and bacteria. Moreover, g-C₃N₄ was integrated into LN/SF nanofiber which enables g-C₃N₄/LN/SF fibers to present a good disinfection under the visible light irradiation by electrospinning, meanwhile could maintain the good mechanical property of ternary-composite membrane. Additionally, the SF based nanofiber membrane displays excellent degradability. Such SF based composite material with enhanced mechanical property could show the versatilities, i.e. improving the efficiencies of filtering PMs and bacteria, killing bacteria, etc., which sheds light on broader applications of SF based membranes as eco-friendly materials.