Tackling Biofilm Formation in Spaceflight: Exploring Antimicrobial Copper Surfaces in Microgravity

Kurzfassung

Biofilms present a significant challenge in environments such as hospitals and industrial facilities, as well as in space environments. Microbial-induced corrosion due to biofilm formation, biofouling and clogging of pipes represents a significant threat to the integrity of spacecraft. In addition, biofilms can serve as reservoirs for opportunistic pathogenic microorganisms, which could pose a threat to astronaut health, particularly given that astronauts exhibit a compromised immune system during spaceflight. One of the strategies employed to mitigate microbial biofilm formation is the use of antimicrobial surfaces. Copper has been known for its antimicrobial properties since ancient times, and additional surface modification using Direct Laser Interference Patterning (DLIP) has been shown to increase antibacterial efficacy. However, further investigation is required to elucidate the interplay between cells, their environment and surfaces under space conditions. This is because fluid dynamics, mass transport and sedimentation are different in microgravity. The BIOFILMS experiment was selected by the European Space Agency (ESA) to test antimicrobial coppercontaining surfaces against bacterial adhesion and biofilm formation under reduced gravity conditions on the International Space Station (ISS). The BIOFILMS experiment included three separate flights to the ISS from August 2021 to March 2023. During these flights, the bacterial model organisms Staphylococcus capitis, Cupriavidus metallidurans, and Acinetobacter radioresistens were incubated on various surfaces inside specially designed hardware to ensure a controlled environment. The initial findings indicate that reduced gravity does not negatively impact the antimicrobial efficacy of copper, and that gravity conditions do not significantly influence adhesion and biofilm formation on reference stainless steel surfaces. Ultimately, final results of the project will provide valuable insights into selecting suitable surfaces and functionalization techniques to reduce biofilm formation, enhance safety, and improve the sustainability of space travel.