title: Bactericidal activity of black silicon.
abstract: Black silicon is a synthetic nanomaterial that contains high aspect ratio nanoprotrusions on its surface, produced through a simple reactive-ion etching technique for use in photovoltaic applications. Surfaces with high aspect-ratio nanofeatures are also common in the natural world, for example, the wings of the dragonfly Diplacodes bipunctata. Here we show that the nanoprotrusions on the surfaces of both black silicon and D. bipunctata wings form hierarchical structures through the formation of clusters of adjacent nanoprotrusions. These structures generate a mechanical bactericidal effect, independent of chemical composition. Both surfaces are highly bactericidal against all tested Gram-negative and Gram-positive bacteria, and endospores, and exhibit estimated average killing rates of up to ~450,000 cells min(-1) cm(-2). This represents the first reported physical bactericidal activity of black silicon or indeed for any hydrophilic surface. This biomimetic analogue represents an excellent prospect for the development of a new generation of mechano-responsive, antibacterial nanomaterials.
authors.affiliation: Faculty of Life and Social Sciences, Swinburne University of Technology, Hawthorn, Victoria 3122, Australia.
authors.forename: Elena P
authors.initials: EP
authors.lastname: Ivanova
authors.forename: Jafar
authors.initials: J
authors.lastname: Hasan
authors.forename: Hayden K
authors.initials: HK
authors.lastname: Webb
authors.forename: Gediminas
authors.initials: G
authors.lastname: Gervinskas
authors.forename: Saulius
authors.initials: S
authors.lastname: Juodkazis
authors.forename: Vi Khanh
authors.initials: VK
authors.lastname: Truong
authors.forename: Alex H F
authors.initials: AH
authors.lastname: Wu
authors.forename: Robert N
authors.initials: RN
authors.lastname: Lamb
authors.forename: Vladimir A
authors.initials: VA
authors.lastname: Baulin
authors.forename: Gregory S
authors.initials: GS
authors.lastname: Watson
authors.forename: Jolanta A
authors.initials: JA
authors.lastname: Watson
authors.forename: David E
authors.initials: DE
authors.lastname: Mainwaring
authors.forename: Russell J
authors.initials: RJ
authors.lastname: Crawford
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000737:chemistry* / Q000494:pharmacology*; D001419:Bacteria / Q000187:drug effects; D001696:Biomechanical Phenomena; D049329:Nanostructures / Q000737:chemistry; D063191:Odonata; D012825:Silicon / Q000737:chemistry* / Q000494:pharmacology*; D013499:Surface Properties; D014921:Wings, Animal / Q000737:chemistry / Q000382:microbiology
chemical_list: D000900:Anti-Bacterial Agents; D012825:Silicon