You are here : Home > International Space Station: the hunt for bacteria

News | Matter & the Universe | Bacteria

International Space Station: the hunt for bacteria

How can we prevent bacteria from settling and proliferating on the inside surfaces of the International Space Station (ISS)? Since 2016, CEA-Leti has been collaborating with Laurence Lemelle and Christophe Place (ENS Lyon) to solve this challenge as part of the Matiss project, which is funded by CNES. In particular, the project aims to develop smart, bio-inspired coatings without toxic metals or nanoparticles.

Published on 14 March 2023

The first series of tests for Matiss were led by Thomas Pesquet and carried out between Nov. 2016 and May 2017. The experiment placed several racks in the ISS in order to hold 22mm-large glass slates that were covered with a hydrophobic coating. 

5th generation coating currently under development

Bacteria require water to attach themselves to a surface and proliferate. This enables them to then create biofilms that can resist cleaning procedures. Hydrophobic coatings eliminate this process and bacteria remain in suspension before being caught by the air filtering system.

CEA-Leti was the starting point for developing this initial anti-bacterial coating. The institution is currently designing a 5th generation of this coating, which will be tested on the ISS in June 2023. The 4th generation coating has been up in space for six months and will soon be brought back to Earth. 

Astronauts spend 10% of their time cleaning!

“This project has an unusual work process,” underlines Guillaume Nonglaton, head of the Matiss project at CEA-Leti. “We have to develop each new generation without having feedback on the previous generation as our colleagues at ENS require months of surface exposure to study the biocontamination of the glass slates.”

Like all humans, the bodies of ISS inhabitants naturally create bacteria and their proliferation is a serious risk. ISS inhabitants are forced to carry out regular cleaning procedures that can take up to 10% of their time!

Combining hydrophobic and hydrophilic surfaces

Anti-bacterial coatings should help alleviate the need for cleaning, in particular in hard to reach areas. Given the microgravity environment of the ISS, these coatings cannot be developed in the same way as they would be for application on Earth. Certain important characteristics change, for example, microgravity impacts bacterial kinetic movement. Thus the need for a completely novel type of coating!

CEA-Leti started by working on hydrophobic coatings before moving onto mixed surfaces that are still majoritarily hydrophobic. By adding lines or circles of hydrophilic surface, bacteria become attached to the surface but are unable to proliferate. 

Depositing an extremely thin layer of coating

The coating is a nanometric, extremely thin layer of chemical agent that is deposited on the glass surface. Once the development process is completed, this coating could be deposited over entire surfaces of steel or aluminum, which are used inside the ISS. Researchers started by testing fluor-based composites. In collaboration with Yoann Roupioz (CNRS), they are now focusing on bio-inspired solutions that do not use toxic materials or nanoparticles. 

“We are particularly focused on highly hydrophilic surfaces based on peptides with an antibacterial function,” explains Guillaume Nonglaton. “These surfaces are never really dry, which is unattractive for bacteria. And if bacteria still end up settling on the surface, they’re eliminated.” The results of this new trial coating should be known in 2025.

Top page