The nanopattern on the surface of cicada wings represents an example of a material that can kill bacteria on contact based solely on its physical surface structure. Ivanova et al.  have shown that cicada wings possess a strong bactericidal activity against Pseudomonas aeruginosa (human pathogen) and showed that the surface of the wings was covered by an array of regularly spaced nanopillar structures. Based upon this understanding, we have reproduced  a similar texturing on different materials. This study presents the characterization and antibacterial activity of nanostructured Si by plasma treatment method using a tetrafluoromethane (CF4) and hydrogen (H2) mixture. Nanostructured-Si is a synthetic nanomaterial that contains high aspect ratio nanoprotrusions on its surface, produced through a reactive-ion etching process. We have shown that the nanoprotrusions on the surfaces produce a mechanical bactericidal effect. Nanostructured-Si exhibited notable activity against three different microorganisms: Gram-negative (Escherichia coli), Gram-positive (Staphylococcus aureus) and spore-forming bacteria (Bacillus cereus) producing a > 5 log10 reduction after 24 h of incubation. Scanning electron microscopy was used to analyze the structure and morphology character of different surfaces evidencing the physical bactericidal activity of the Nanostructured-Si. Finally, we also present some preliminary results of the implementation of the texturing process on materials for biomedical applications. These results provide excellent prospects for the development of a new generation of antibacterial surfaces.
 E.P. Ivanova, et al., Bactericidal activity of black silicon, Nat. Commun. 4 (2013) (article number: 2838) 10.1038/ncomms3838.
 E. Vassallo, et al., Bactericidal performance of nanostructured surfaces by fluorocarbon plasma, Materials Science & Engineering C 80 (2017) 117-121Bottom of Form