Promotion of biofilm production via atmospheric-pressure plasma-polymerization for biomedical applications

The ability of bacteria to form biofilms that enhance their resistance to disinfectants and antibiotics is a matter of concern in the fields of food processing and healthcare. Since culture conditions in laboratories are not exactly the same as in the real environments where bacterial infection takes place, developing models that rapidly produce biofilm on test surfaces has become an interesting topic of research. In this work, Pseudomonas aeruginosa biofilm production on polystyrene Petri dishes was promoted by atmospheric-pressure plasma -polymerization of 3-(Aminopropyl)triethoxysilane (APTES). Different coatings were deposited varying only the number of plasma-polymerization passes. Biofilm productions, ranging from 157% to 457% relative to that on the uncoated dishes, were quantified after 24-h incubation. According to morphological and chemical characterizations, the APTES precursor promoted biofilm production in several ways: providing amines that facilitated the attachment of more bacterial cells than on uncoated dishes, inducing an oxidative stress to the attached bacteria that caused an overproduction of extracellular polymeric substances, and generating siloxane-based particles that formed a granular pattern that facilitated bacterial accumulation in its valleys. Comparing the coatings, a direct relationship was identified between the number of plasma-polymerization passes, the roughness and the biofilm production.