Evaluation of bacterial adherence and biofilm development on an anodized stainless-steel surface for the prevention of osteosynthesis-associated infections

Background: Implant-associated infections remain a major challenge in orthopaedic surgery. This study aimed to evaluate the anti-adherent and anti-biofilm properties of a novel anodized 316L stainless-steel (A 316L SS) surface against common pathogens in osteosynthesis-associated infections (OAIs). Methods: Bacterial adherence and biofilm formation of Staphylococcus aureus, Staphylococcus epidermidis, Enterococcus faecalis, Cutibacterium acnes, Escherichia coli, and Pseudomonas aeruginosa were assessed on A 316L SS and non-anodized 316L stainless steel (Ref 316L SS). Adherence was evaluated after 90 min using fluorescence microscopy. Biofilm development was examined after 24–48 h in synthetic synovial fluid (SSF) using colony counts and scanning electron microscopy (SEM). Results: A 316L SS significantly reduced bacterial adherence and surface coverage for all species tested compared to Ref 316L SS. In biofilm assays, A 316L SS exhibited notable anti-biofilm properties, with significantly reduced biofilm formation for all species. E. faecalis and C. acnes also showed lower planktonic bacterial counts. Imaging confirmed decreased bacterial presence and extracellular matrix on A 316L SS. Conclusions: A 316L SS shows strong anti-adherent and anti-biofilm properties against common orthopaedic pathogens, even under in vivo-like conditions. This surface modification strategy holds significant potential for reducing implant-associated infections and warrants further investigation for clinical applications.