Femtosecond laser modified metal surfaces alter biofilm architecture and reduce bacterial biofilm formation

Biofilm formation{,} or microfouling{,} is a basic strategy of bacteria to colonise a surface and may happen on surfaces of any nature whenever bacteria are present. Biofilms are hard to eradicate due to the matrix in which the bacteria reside{,} consisting of strong{,} adhesive and adaptive self-produced polymers such as eDNA and functional amyloids. Targeting a biofilm matrix may be a promising strategy to prevent biofilm formation. Here{,} femtosecond laser irradiation was used to modify the stainless steel surface in order to introduce either conical spike or conical groove textures. The resulting topography consists of hierarchical nano-microstructures which substantially increase roughness. The biofilms of two model bacterial strains{,} P. aeruginosa PA01 and S. aureus ATCC29423{,} formed on such nanotextured metal surfaces{,} were considerably modified due to a substantial reduction in amyloid production and due to changes in eDNA surface adhesion{,} leading to significant reduction in biofilm biomass. Altering the topography of the metal surface{,} therefore{,} radically diminishes biofilm development solely by altering biofilm architecture. At the same time{,} growth and colonisation of the surface by eukaryotic adipose tissue-derived stem cells were apparently enhanced{,} leading to possible further advantages in controlling eukaryotic growth while suppressing prokaryotic contamination. The obtained results are important for developing anti-bacterial surfaces for numerous applications.