Efficacy of biomimetic surfaces in mitigating Escherichia coli biofilms in the presence of an amphiphilic casein conditioning film

Biofilms represent a persistent challenge on food contact surfaces, compromising hygiene, safety, and product quality. This study aimed to fabricate and characterize biomimetic wax surfaces inspired by the micro- and nanostructured topographies of Cauliflower, White Cabbage, and Leek leaves, to assess their efficacy in mitigating Escherichia coli biofilm formation, and to determine the effect of conditioning films composed of amphiphilic casein on the surfaces' antibiofilm properties. Surface characterization by Scanning Electron Microscopy (SEM), Optical Profilometry (OP), and water contact angle measurements confirmed the successful replication of plant topographies and revealed that casein conditioning (5% w/v) altered surface morphology and increased wettability. Despite partial coverage by casein, biomimetic surfaces retained distinct topographical features and higher roughness compared to Flat controls. Microbiological assays demonstrated the antibiofilm effects of the biomimetic surfaces, with topography emerging as the primary factor. Cauliflower and Leek surfaces reduced the number of E. coli cells, measured as colony-forming units (CFU), by up to 89% relative to Flat controls. Casein conditioning alone contributed to a smaller, yet notable, decrease in all biofilm parameters, with cell counts, thickness measured by Optical Coherence Tomography (OCT), and biovolume determined by confocal microscopy, showing reductions of 67%, 29%, and 25%, respectively. When topography and conditioning were considered together, a combined effect was observed, with White Cabbage and Leek surfaces achieving the greatest overall reductions. These findings showed that surface topography can effectively enhance biofilm inhibition, even in protein-conditioned environments. • Biomimetic wax surfaces mimicked Cauliflower, White Cabbage, and Leek topographies • Casein conditioning altered surface morphology and increased wettability • Topography was the main factor reducing E. coli cell numbers, up to 89% • Casein further enhanced inhibition, with combined effects on WC and L surfaces • Biomimetic surfaces retained antibiofilm efficacy when protein-conditioned