Bactericidal Action of Smooth and Plasma Micro-Nanotextured Polymeric Surfaces with Varying Wettability, Enhanced by Incorporation of a Biocidal Agent

The use of antibacterial surfaces is an effective way to reduce exposure to pathogens and therefore infections. Several methods to fabricate antibacterial surfaces using surface modification methods as well as a bactericidal agent incorporation inside materials have been reported. However, in most cases the factors affecting the antibacterial behavior of a surface are not discussed in detail. Here, a comparative study on the antibacterial properties of surfaces with different characteristics against Gram-negative bacteria (Escherichia coli) under dynamic conditions is presented, aiming to unravel the interplay among the most important factors when realizing an antibacterial surface, that is, surface morphology, wetting properties, and the use of a bactericidal agent. Significant bactericidal efficacy for the micro-nanotextured, superhydrophilic surfaces is demonstrated, possibly due to a mechanical killing induced by the interaction of bacteria with the micro-nanotopography. On the other hand, superhydrophobic surfaces without any bactericidal agent exhibit low interaction with the bacteria containing medium and therefore lower bactericidal action, whereas superhydrophobic surfaces with a bactericidal agent exhibit extreme non-wetting properties and rapid bactericidal effect through release of Cu particles. Finally, the role of the hydrophobic coating as barrier against uncontrolled release of the bactericidal agent when deposited as top layer is also showcased.

Automated summary

The study compared the antibacterial properties of surfaces with different characteristics against Gram-negative bacteria under dynamic conditions, revealing the interplay among surface morphology, wetting properties, and the use of bactericidal agents. Surfaces with micro-nanostructures and superhydrophilicity showed significant bactericidal efficacy, while superhydrophobic surfaces exhibited lower bactericidal action.