In this master’s thesis, we evaluated the efficacy of mechanical removal of bacterial biofilms using anisotropic superparamagnetic nanoparticles under rotating magnetic fields. We tested three types of nanoparticles (Si, ToSi, Hex) with varying porosity of the outer silica shell. The removal efficacy of biofilms formed by three bacterial species (Escherichia coli, Lactococcus lactis and Pseudomonas fragi) was assessed using colony-forming unit (CFU) counting and fluorescence measurements. The experiments were performed under two types of magnetic stirring (classic and 96-well stirrer) at two speeds (300 and 600 rotations/min) and two treatment durations (30 and 60 min). The highest removal (~90 %) was achieved with E. coli using the classic stirrer. Biofilms of P. fragi were the most resistant and responded better to shorter treatments. Differences in nanoparticle porosity did not significantly affect biofilm removal. In addition, we evaluated the cytotoxicity of nanoparticles on the intestinal epithelial cell line Caco-2 using resazurin assay and light microscopy. No adverse effects on cell viability or monolayer structure were observed under any tested conditions. Our results confirm that magnetic nanoparticles represent an effective and safe approach for mechanical disruption of bacterial biofilms, with potential applications in biomedical and biotechnological contexts.
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