Antibiofilm coatings through atmospheric pressure plasma for 3D printed surgical instruments

Recently, medical applications for 3D printing are expanding rapidly and are expected to revolutionize health care, specifically, manufacturing surgical guides and protective face mask against coronavirus (COVID-19). These instruments come in contact with the human tissues, being necessary 3D printed materials free of pathogenic microbes or other contaminants. Therefore, they must be sterilized to avoid that bacteria can attach to the surface and produce biofilm. With the aim of avoiding bacterial biofilm formation and minimize the health risks, acrylic acid (AcAc) coatings applied by plasma-polymerization have been deposited on 3D printed polylactic acid (PLA) Petri dishes. Six antimicrobial-resistant clinical and two susceptible control strains of Pseudomonas aeruginosa and Staphylococcus aureus species were analyzed. AcAc coatings provide the surface with greater hydrophilicity and, consequently, the formation of a hydration layer, whose thickness is related to the surface roughness. This hydration layer could explain the reduction of bacterial attachment and, consequently, the biofilm formation. Antibiofilm coatings are more successful against P. aeruginosa strains than against S. aureus ones; due to some coatings presents a smaller topography scale than the P. aeruginosa length, reducting the contact area between the bacteria and the coating, and causing a potential rupture of the cellular membrane. AcAc coatings with less number of plasma passes were more effective, and showed up to a 50% relative biofilm reduction (in six of the eight strains studied) compared with the untreated plates.