Covalent binding of vitamin K3 photosensitizers to nanofibrous membranes for daylight-driven antimicrobial applications

Pathogenic microorganism infections significantly threaten public health. Conventional personal protective equipment (PPE) reduces infection risk by physically blocking pathogen transmission pathways, devoid of intrinsic antimicrobial properties. Previously, a photoinduced antimicrobial PPE material was developed by physically blending vitamin K₃ with a polymeric matrix. However, VK₃ might leach out from the material matrix during long-term use due to the weak interactions, reducing its photoinduced antimicrobial efficiency. To overcome this challenge, we report a potentially scalable approach to modify the VK₃ covalently onto a nanofibrous membrane. The obtained photoactive bioprotective nanofibrous membrane VK₃-EVOH exhibits efficient productivity of various reactive oxygen species (ROS), such as OH, H₂O₂, and ¹O₂, through Type I and Type II reactions under daylight irradiation. The rapid generation of biocidal ROS ensures high antimicrobial efficiency. Over 6 log CFU mL⁻¹ of pathogens are inactivated within 90 min of photoirradiation, even under rich chemical oxygen demand (COD) conditions. Benefiting from the covalent bonding, the VK₃-EVOH maintains its high antimicrobial efficiency after 5 cycles. Moreover, the VK₃-EVOH could serve as an active defense layer in typical PPE, offering contact-based pathogen killing in aerosol and liquid forms and demonstrating its viability in PPE applications.