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 on astronauts’ ability to prevent the acquisition of infectious agents or reactivation of latent infection. Microgravity could also affect virulence and biofilm formation of potential microbial pathogens, thus providing ample opportunity for microbial contamination of the environment. This will be amplified by the extension of mission duration and the need to recycle onboard, including human wastes. 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. A substantial 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 reduce microbial growth and ease their cleaning processes. The internal environment of a space station could provide the conditions needed for self-cleaning and antibacterial surfaces to operate. Within this project, we will aim at realizing efficient coatings based on titanium dioxide (TiO2), a well-known and studied photocatalyst having the potential to promote the removal of most organic compounds and toxic ions from water, owing to the high reactivity of photo-formed electrons and holes under UV irradiation [DOI: 10.1016/j.apcatb.2018.03.012]. The purpose of the present project is to improve the photocatalytic efficiency of TiO2 coatings, pursuing either an increased number of active sites for photodegradation by tuning the surface-to-volume ratio and the overall surface symmetry, as well an enhanced absorption of UV and visible light, to increase the reactive species photo-formation yield.
