title: Hydrophobic pinning with copper nanowhiskers leads to bactericidal properties.
abstract: The considerable morbidity associated with hospitalized patients and clinics in developed countries due to biofilm formation on biomedical implants and surgical instruments is a heavy economic burden. An alternative to chemically treated surfaces for bactericidal activity started emerging from micro/nanoscale topographical cues in the last decade. Here, we demonstrate a putative antibacterial surface using copper nanowhiskers deposited by molecular beam epitaxy. Furthermore, the control of biological response is based on hydrophobic pinning of water droplets in the Wenzel regime, causing mechanical injury and cell death. Scanning electron microscopy images revealed the details of the surface morphology and non-contact mode laser scanning of the surface revealed the microtopography-associated quantitative parameters. Introducing the bacterial culture over nanowhiskers produces mechanical injury to cells, leading to a reduction in cell density over time due to local pinning of culture medium to whisker surfaces. Extended culture to 72 hours to observe biofilm formation revealed biofilm inhibition with scattered microcolonies and significantly reduced biovolume on nanowhiskers. Therefore, surfaces patterned with copper nanowhiskers can serve as potential antibiofilm surfaces. The topography-based antibacterial surfaces introduce a novel prospect in developing mechanoresponsive nanobiomaterials to reduce the risk of medical device biofilm-associated infections, contrary to chemical leaching of copper as a traditional bactericidal agent.
authors.affiliation: Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany.
authors.forename: Ajay Vikram
authors.initials: AV
authors.lastname: Singh
authors.affiliation: CSF Thin Films Group, Max Planck Institute for Intelligent Systems, Stuttgart, Germany.
authors.forename: Semanur
authors.initials: S
authors.lastname: Baylan
authors.affiliation: Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany.
authors.forename: Byung-Wook
authors.initials: BW
authors.lastname: Park
authors.affiliation: CSF Thin Films Group, Max Planck Institute for Intelligent Systems, Stuttgart, Germany.
authors.forename: Gunther
authors.initials: G
authors.lastname: Richter
authors.affiliation: Physical Intelligence Department, Max Planck Institute for Intelligent Systems, Stuttgart, Germany.
authors.forename: Metin
authors.initials: M
authors.lastname: Sitti
mesh_terms: D000900:Anti-Bacterial Agents / Q000494:pharmacology*; D018441:Biofilms / Q000187:drug effects; D003300:Copper / Q000737:chemistry* / Q000494:pharmacology; D057927:Hydrophobic and Hydrophilic Interactions; D008855:Microscopy, Electron, Scanning; D046529:Microscopy, Electron, Transmission; D013499:Surface Properties
chemical_list: D000900:Anti-Bacterial Agents; D003300:Copper