Coupling Cu-MOF and Flexible Wood as Active Antimicrobial Membrane

Airborne microbes such as bacteria, viruses, or fungi are a major cause of respiratory ailments, including allergies and pathogenic infections. Despite advances in modern healthcare and public health measures, preventing the transmission of airborne microbes is still very challenging. The microbes may stay alive for a while after landing on a face mask, giving them the chance to infect another individual. In face masks, the laminated materials are primarily made of nonrenewable polystyrene, polyethylene, polycarbonate, or polyester fibers and are even coated with polytetrafluoroethylene for high-efficiency ones. A holistic approach is to disinfect the microbes on face mask before inhaling into the upper respiratory tract with functionalized green materials. In this work, fast-growing balsa wood (BW) sheets were first converted into flexible membrane, followed by in situ growth of Cu-based metal-organic framework (Cu-MOF) into pores. The membrane maintains great flexibility, as demonstrated through mechanical folding and twisting. The agar diffusion test was used to qualitatively assess the efficacy of a flexible membrane coupled with MOF particles in antimicrobial application against Gram-positive and Gram-negative bacteria causing respiratory illness. The inhibition zones with a radius of ∼2 mm were observed against Klebsiella pneumoniae and Pseudomonas aeruginosa, while a larger inhibition zone with a radius of ∼4 mm was recorded against Staphylococcus aureus, indicating great potential in inhibiting the production of all strains of microbes. Such green functional materials would find a broad bio application to benefit human health.