A new antimicrobial metal-based surface coating has been tested and proven to be effective at fighting superbugs on the International Space Station.
The coating, which is called AGXX, is made up of thin layers of silver and ruthenium treated with vitamin C. If successful, the coating will be used in future missions to keep astronauts safe and healthy in space.
Fighting Bacteria In Space
When astronauts leave Earth, bacteria hitch a ride and end up on the ISS. Previous research has found that the extreme conditions from spaceflight make the bacteria tougher and with microgravity and cosmic radiation altering the immune response of the crew, astronauts become more susceptible to infection.
"Spaceflight can turn harmless bacteria into potential pathogens," stated Elisabeth Grohmann from Beuth University of Applied Sciences in Berlin. "Just as stress hormones leave astronauts vulnerable to infection, the bacteria they carry become hardier — developing thick protective coatings and resistance to antibiotics — and more vigorous, multiplying and metabolizing faster."
However, researchers have made a massive stride forward in the fight against bacteria in space. In a study published in Frontiers in Microbiology, a team demonstrated how AGXX reduced the number of bacteria in surfaces of the ISS.
"After 6 months exposure on the ISS, no bacteria were recovered from AGXX-coated surfaces," Grohmann and team reported. "With prolonged exposure time a few bacteria escaped the antimicrobial action. The antimicrobial test-materials are static surfaces, where dead cells, dust particles and cell debris can accumulate over time and interfere with the direct contact between the antimicrobial surface and the bacteria."
The coating contains silver, which has been used to prevent microbial growth since prehistory, and ruthenium. Both were conditioned with vitamin C.
The AGXX works by producing free radicals that damage the bacterial cell membrane. According to the researchers, AGXX can kill all kinds of bacteria and certain kinds of fungi, yeasts, and viruses.
Protecting Astronauts During Deep Space Exploration
Moreover, the coating is self-regenerating. It can be used for a long time, which is perfect for deep space exploration.
Grohmann added that the risk of infection increases with the duration of spaceflight, potentially endangering the lives of astronauts. If NASA pushes through with plans to send humans to the surface of Mars, the space agency first has to figure out how to protect astronauts from bacteria during the nine-month travel from Earth to the red planet.
The team said that they will continue studying and improving the performance of AGXX. The coating will also be tested in the isolation mission between NASA and Russia's Institute of Biomedical Problems.