Current status of the BIOFILMS ISS experiment: testing functionalized antimicrobial surfaces in space

Kurzfassung

Microbial biofilms are universally present in our environment. However, biofilms can be problematic since they can damage materials and pose a health risk. Especially during space travel, where crew health is top priority and failure of equipment is detrimental, methods for preventing biofilm formation are vital. Antimicrobial active metals, such as copper, have already shown their potential on Earth [1]. Furthermore, additional surface functionalization of copper surfaces through direct laser interference patterning using ultra short pulses (USP-DLIP) can increase the antimicrobial efficiency and biofilm inhibition for certain types of bacteria [2]. The spaceflight project “BIOFILMS” investigates the antimicrobial effect of these functionalized copper surfaces in microgravity by using a unique experimental setup on board the ISS. For this, three bacterial species Staphylococcus capitis subsp. capitis, Cupriavidus metallidurans and Acinetobacter radioresistens were selected. Copper and brass were selected as antimicrobial metals and steel is used as an inert reference. All three metals are tested with and without surface functionalization. For the experiment, specific hardware was developed that allows bacterial biofilm formation in liquid medium in immediate contact to the different surfaces. The first results from the Science Verification Test and Experiment Sequence test showed that the hardware is biocompatible with the selected bacterial species and is suitable for the scientific requirements and proposed experimental sequence. The first launch for BIOFILMS was in August 2021 with SpX 23 with the first set of samples. Aboard the ISS, the hardware was integrated into the KUBIK incubator inside the Columbus laboratory. In this incubator, the experiment was incubating at 20 °C for 14 days in microgravity (Space), 0.4 x g (Mars) and 1 x g (Earth) as control. The second and third set of samples will be launched in 2022. Preliminary experiments on Earth indicated that the functionalized copper surfaces have altered antimicrobial effects on the selected bacteria.