Environmental friendly and scalable fabrication of antibacterial ZnO-nanostructured surfaces

In this work we show that nanostructured ZnO surfaces, fabricated by a fully water-based protocol, exhibit enhanced bactericidal action against \textit{E. coli}, both on the surface itself as well as remotely, and in the absence of sunlight (bacterial killing efficiency of 9250 cells cm$^{\mathrm{-2}}$hr$^{\mathrm{-1}})$. They are also able to disinfect contaminated water (\textgreater 99.98{\%} elimination of bacteria) while satisfying the legal limits on the released Zinc ion concentration (0.73 \textpm 0.15 ppm). Using the same ZnO nanostructures and adding hydrophobization, we obtain self-cleaning surfaces with ultra-low bacterial adhesion. This is achieved either by deposition of a water-soluble fluoroalkylsilane or ethanol-soluble stearic acid. The resulting impressive and tunable antibacterial behavior, combined with the `green' and scalable fabrication, render these materials excellent candidates in sustainable antibacterial and water purification applications.