Effect of Nanoparticles Type and Content on the Antimicrobial Activity of Magnetoelectric Polymer-Based Composites

Antimicrobial materials are essential for the development of coatings for high traffic surfaces to prevent the adhesion and proliferation of microorganisms, playing a crucial role in infection control. In this study, different magnetoelectric nanocomposites exhibiting antimicrobial activity upon magnetic stimulation were developed by solvent casting. The nanocomposites, composed of poly(vinylidene fluoride-co-trifluoroethylene) [P(VDF-TrFE)] with different contents (10 and 20% wt) of CoFe₂O₄ (CFO) or Fe₃O₄ nanoparticles, were developed to respond to a variable magnetic field, mechanically stimulating the piezoelectric component of the material and inducing surface potential variations. The antimicrobial properties of these materials were evaluated by exposing them to different magnetic frequencies (0.3 and 1 Hz) in a custom-made magnetic bioreactor. The growth of Escherichia coli (E. coli) and Staphylococcus aureus (S. aureus) was significantly inhibited, particularly in the P(VDF-TrFE) nanocomposite with 20% CFO NPs, under magnetic stimulation at 1 Hz (bacterial cell viability ≈15%) compared to static conditions (bacterial cell viability ≈35%). This study highlights the potential of magnetic stimulation, in combination with magnetoelectric materials, as an effective strategy for the development of antimicrobial surfaces.