PATINA: Optimisation of PhotocATalytIc aNtibActerial coatings

Prolonged human spaceflights will introduce unique challenges in mitigating the risk of infection. Exposure to microgravity, radiations, and stress alter human immunoregulatory responses, thus impacting astronauts’ ability to prevent the acquisition of infectious agents or reactivation of latent infection. Microgravity also affects virulence, growth kinetics, and biofilm formation of potential microbial pathogens. These conditions provide ample opportunity for heavy microbial contamination of the environment. The overall strategy to mitigate such adverse medical events is prevention. Appropriate steps should begin early in the design phase of new spacecraft and habitats. While minimization of infectious diseases could be achieved by a systematic campaign of medical treatments of the crewmembers before spaceflight, a strong contribution could be obtained by a proper choice of the materials used to realize the habitable volumes and the air and water purification systems by providing the internal surfaces with specific functionalities to suppress microbial growth and ease their cleaning processes. The internal environment of a space station could provide the conditions needed for “Earth-optimized” self-cleaning and antibacterial surfaces to operate. This project aims to realize efficient coatings based on titanium dioxide (TiO2), a well-known and studied photocatalyst that can promote the removal of most organic compounds and toxic ions from water, owing to the high reactivity photo-formed electrons and holes under UV irradiation. The purpose of the present project is to improve the photocatalytic efficiency of TiO2 coatings, pursuing the optimization of the photo-degradation process by tuning the surface-to-volume ratio and the overall surface symmetry and by enhancing the absorption of UV and visible light to increase the reactive species photo-formation yield.

Project funding: European Space agency (ESA)