The identity of implant materials governs the antimicrobial efficacy of SET-M33

The physical and chemical properties of implanted materials play a key role in their interaction with synthetic peptides that exert antimicrobial activity. In this study, we explored the diffusion properties and efficacy of the SET-M33 antimicrobial peptide in combination with artificial substrates, comprising cardiac implantable electronic devices (CIEDs) or porous protective envelopes. We found that porous materials, such as biosynthesized cellulose, polymeric meshes, and electrospun membranes, were conducive to SET-M33 diffusion. The diffusion dynamics was controlled by the intrinsic fibrous architecture of the materials. Biosynthesized cellulose supported the peptide's antimicrobial activity against E. coli and S. aureus. The efficacy of SET-M33 was instead reduced when combined with the other tested porous membranes and non-porous CIED interfaces, such as titanium and silicone. On the other hand, the low porosity of biosynthesized cellulose membranes, while effective in retaining the drug, diminished diffusion and thus peptide availability. In light of these findings, the implications for the use of antimicrobial peptides in the prevention of CIED surgical pocket infections are discussed.