Promising Antimicrobial Properties of Silicon-Based Thin-Film Coatings

Silicon-based thin films, such as silicon and silicon-based alloys, have been intensively studied, especially for their use in microelectronics and large area electronics. However, they also show interesting properties regarding their biological interaction, although these characteristics have been studied to a lower extent. Recently, promising antibacterial properties of some silicon-based materials have been investigated, showing their potential ability to reduce the adhesion of some types of bacteria on the surfaces onto which they are applied. Since these properties rely on the reduction of bacterial adhesion, instead of exploiting the release of antibacterial agents such as Ag ions or nanoparticles, they show the advantage of preventing potentially harmful long-time effects that could be exerted by these agents in the host tissues. Moreover, this approach avoids the risk that the release intensity of these agents is reduced over time due to their depletion inside the material. Due to the wide range of interesting properties of silicon-based materials, including biocompatibility increase, barrier action against the release of chemicals, and tuning of surface energy, the production of multifunctional coatings could also be possible. In this chapter, the most important properties of silicon-based thin films are reviewed, and some results concerning the potential antibacterial properties of silicon–oxygen amorphous thin-film alloys (a-SiOx) are presented in detail.