Anisotropic Magnetic Particles with Different Dimensions, Morphologies and Surface Grafting for Magnetic Field-Assisted Biofilm Removal

Microorganisms in biofilms are protected from environmental stressors and therefore exhibit strong tolerance to conventional removal strategies, including chemical disinfectants and antibiotics. In this study, we systematically evaluated emerging biofilm removal approaches on Listeria innocua biofilms using nanomaterial-based methods. Anisotropic magnetic particles (AMPs), composed of iron oxide, and silver nanoparticles, known for their intrinsic antibacterial properties, were used to assess the potential of nanostructure-triggered biofilm disruption. We investigated how AMP properties, specifically surface roughness and particle size, influence biofilm removal under magnetic actuation, using both classical colony-forming unit quantification (viability assessment) and fluorescence-based detection of bacteria via reporter protein. Although individual AMP characteristics contributed only modestly to biofilm disruption, a synergistic effect was observed when AMPs were grafted with silver nanoparticles. Pronounced species-dependent variability of silver-based treatments was also observed for Enterococcus faecalis and Candida albicans. Our results indicate that hybrid magneto–chemical strategies represent a promising and likely necessary approach for achieving reliable and robust biofilm removal from surfaces.