Preliminary results from the BIOFILMS experiment on the ISS testing laserpatterned antimicrobial surfaces against bacterial biofilm formation

Abstract

Biofilms are agglomerates of microorganisms that envelop themselves with a self-produced matrix of extracellular polymeric substances. As a result, biofilms protect themselves against environmental influences and are highly resistant to antibiotics and disinfectants. Biofilms can damage materials through biocorrosion and biofouling and can harbor pathogenic organisms. Therefore, biofilms are not only undesirable in hospitals and industry, but also in spacecraft for human health and spacecraft integrity. With the help of antimicrobial copper surfaces, the formation of biofilms can be prevented or at least reduced, as these surfaces kill the microorganisms on contact and thus prevent the first step of biofilm formation, adhesion. Since the interaction between cells, surrounding medium and surface is altered under space conditions, the influence of microgravity on the effect of antimicrobial surfaces required to be investigated further. The aim of the ESA spaceflight experiment “BIOFILMS” is to test the antimicrobial effect of copper and brass on bacterial biofilm formation (Staphylococcus capitis, Cupriavidus metallidurans, Acinetobacter radioresistens) under altered gravitational conditions (pg and 0.4 x g). Within the experiment, not only smooth surfaces were used, but also surfaces with a modified topography that can increase their antimicrobial efficacy. The different bacteria were incubated on different surfaces inside a dedicated experiment hardware to allow biofilm formation under controlled conditions in Space. In total, the BIOFILMS experiment consisted of three flights to the International Space Station (August 2021, June 2022 and March 2023) in order to accommodate all sample configurations (metal type, surface topography, type of bacteria, gravity conditions). Here we present preliminary results from the experiment while post-flight analysis of all samples from the three flights is ongoing. The results of the experiment will help make spaceflight safer and more sustainable by providing new insights into appropriate surfaces and functionalization processes that help reduce biofilm formation. Auth